Date: 2026-07-30T21:14:05+00:00

Actual source code: dm.c

      1: #include <petscvec.h>
      2: #include <petsc/private/dmimpl.h>
      3: #include <petsc/private/dmlabelimpl.h>
      4: #include <petsc/private/petscdsimpl.h>
      5: #include <petscdmplex.h>
      6: #include <petscdmceed.h>
      7: #include <petscdmfield.h>
      8: #include <petscsf.h>
      9: #include <petscds.h>

     11: #ifdef PETSC_HAVE_LIBCEED
     12: #include <petscfeceed.h>
     13: #endif

     15: PetscClassId DM_CLASSID;
     16: PetscClassId DMLABEL_CLASSID;
     17: PetscLogEvent DM_Convert, DM_GlobalToLocal, DM_LocalToGlobal, DM_LocalToLocal, DM_LocatePoints, DM_Coarsen, DM_Refine, DM_CreateInterpolation, DM_CreateRestriction, DM_CreateInjection, DM_CreateMatrix, DM_CreateMassMatrix, DM_Load, DM_View, DM_AdaptInterpolator, DM_ProjectFunction;

     19: const char *const DMBoundaryTypes[]          = {"NONE", "GHOSTED", "MIRROR", "PERIODIC", "TWIST", "DMBoundaryType", "DM_BOUNDARY_", NULL};
     20: const char *const DMBoundaryConditionTypes[] = {"INVALID", "ESSENTIAL", "NATURAL", "INVALID", "LOWER_BOUND", "ESSENTIAL_FIELD", "NATURAL_FIELD", "INVALID", "UPPER_BOUND", "ESSENTIAL_BD_FIELD", "NATURAL_RIEMANN", "DMBoundaryConditionType",
     21:                                                 "DM_BC_",  NULL};
     22: const char *const DMBlockingTypes[]          = {"TOPOLOGICAL_POINT", "FIELD_NODE", "DMBlockingType", "DM_BLOCKING_", NULL};
     23: const char *const DMPolytopeTypes[] =
     24:   {"vertex",  "segment",      "tensor_segment", "triangle", "quadrilateral",  "tensor_quad",  "tetrahedron", "hexahedron", "triangular_prism", "tensor_triangular_prism", "tensor_quadrilateral_prism", "pyramid", "FV_ghost_cell", "interior_ghost_cell",
     25:    "unknown", "unknown_cell", "unknown_face",   "invalid",  "DMPolytopeType", "DM_POLYTOPE_", NULL};
     26: const char *const DMCopyLabelsModes[] = {"replace", "keep", "fail", "DMCopyLabelsMode", "DM_COPY_LABELS_", NULL};

     28: /*@
     29:   DMCreate - Creates an empty `DM` object. `DM`s are the abstract objects in PETSc that mediate between meshes and discretizations and the
     30:   algebraic solvers, time integrators, and optimization algorithms in PETSc.

     32:   Collective

     34:   Input Parameter:
     35: . comm - The communicator for the `DM` object

     37:   Output Parameter:
     38: . dm - The `DM` object

     40:   Level: beginner

     42:   Notes:
     43:   See `DMType` for a brief summary of available `DM`.

     45:   The type must then be set with `DMSetType()`. If you never call `DMSetType()` it will generate an
     46:   error when you try to use the `dm`.

     48:   `DM` is an orphan initialism or orphan acronym, the letters have no meaning and never did.

     50: .seealso: [](ch_dmbase), `DM`, `DMSetType()`, `DMType`, `DMDACreate()`, `DMDA`, `DMSLICED`, `DMCOMPOSITE`, `DMPLEX`, `DMMOAB`, `DMNETWORK`
     51: @*/
     52: PetscErrorCode DMCreate(MPI_Comm comm, DM *dm)
     53: {
     54:   DM      v;
     55:   PetscDS ds;

     57:   PetscFunctionBegin;
     58:   PetscAssertPointer(dm, 2);

     60:   PetscCall(DMInitializePackage());
     61:   PetscCall(PetscHeaderCreate(v, DM_CLASSID, "DM", "Distribution Manager", "DM", comm, DMDestroy, DMView));
     62:   ((PetscObject)v)->non_cyclic_references = &DMCountNonCyclicReferences;
     63:   v->setupcalled                          = PETSC_FALSE;
     64:   v->setfromoptionscalled                 = PETSC_FALSE;
     65:   v->ltogmap                              = NULL;
     66:   v->bind_below                           = 0;
     67:   v->bs                                   = 1;
     68:   v->coloringtype                         = IS_COLORING_GLOBAL;
     69:   PetscCall(PetscSFCreate(comm, &v->sf));
     70:   PetscCall(PetscSFCreate(comm, &v->sectionSF));
     71:   v->labels                    = NULL;
     72:   v->adjacency[0]              = PETSC_FALSE;
     73:   v->adjacency[1]              = PETSC_TRUE;
     74:   v->depthLabel                = NULL;
     75:   v->celltypeLabel             = NULL;
     76:   v->localSection              = NULL;
     77:   v->globalSection             = NULL;
     78:   v->defaultConstraint.section = NULL;
     79:   v->defaultConstraint.mat     = NULL;
     80:   v->defaultConstraint.bias    = NULL;
     81:   v->coordinates[0].dim        = PETSC_DEFAULT;
     82:   v->coordinates[1].dim        = PETSC_DEFAULT;
     83:   v->sparseLocalize            = PETSC_TRUE;
     84:   v->dim                       = PETSC_DETERMINE;
     85:   PetscCall(PetscDSCreate(PETSC_COMM_SELF, &ds));
     86:   PetscCall(DMSetRegionDS(v, NULL, NULL, ds, NULL));
     87:   PetscCall(PetscDSDestroy(&ds));
     88:   PetscCall(PetscHMapAuxCreate(&v->auxData));
     89:   v->dmBC              = NULL;
     90:   v->coarseMesh        = NULL;
     91:   v->outputSequenceNum = -1;
     92:   v->outputSequenceVal = 0.0;
     93:   PetscCall(DMSetVecType(v, VECSTANDARD));
     94:   PetscCall(DMSetMatType(v, MATAIJ));

     96:   *dm = v;
     97:   PetscFunctionReturn(PETSC_SUCCESS);
     98: }

    100: /*@
    101:   DMClone - Creates a `DM` object with the same topology as the original.

    103:   Collective

    105:   Input Parameter:
    106: . dm - The original `DM` object

    108:   Output Parameter:
    109: . newdm - The new `DM` object

    111:   Level: beginner

    113:   Notes:
    114:   For some `DM` implementations this is a shallow clone, the result of which may share (reference counted) information with its parent. For example,
    115:   `DMClone()` applied to a `DMPLEX` object will result in a new `DMPLEX` that shares the topology with the original `DMPLEX`. It does not
    116:   share the `PetscSection` of the original `DM`.

    118:   The clone is considered set up if the original has been set up.

    120:   Use `DMConvert()` for a general way to create new `DM` from a given `DM`

    122: .seealso: [](ch_dmbase), `DM`, `DMDestroy()`, `DMCreate()`, `DMSetType()`, `DMSetLocalSection()`, `DMSetGlobalSection()`, `DMPLEX`, `DMConvert()`
    123: @*/
    124: PetscErrorCode DMClone(DM dm, DM *newdm)
    125: {
    126:   PetscSF              sf;
    127:   Vec                  coords;
    128:   void                *ctx;
    129:   MatOrderingType      otype;
    130:   DMReorderDefaultFlag flg;
    131:   PetscInt             dim, cdim, i;
    132:   PetscBool            sparse;

    134:   PetscFunctionBegin;
    136:   PetscAssertPointer(newdm, 2);
    137:   PetscCall(DMCreate(PetscObjectComm((PetscObject)dm), newdm));
    138:   PetscCall(DMCopyLabels(dm, *newdm, PETSC_COPY_VALUES, PETSC_TRUE, DM_COPY_LABELS_FAIL));
    139:   (*newdm)->leveldown     = dm->leveldown;
    140:   (*newdm)->levelup       = dm->levelup;
    141:   (*newdm)->prealloc_only = dm->prealloc_only;
    142:   (*newdm)->prealloc_skip = dm->prealloc_skip;
    143:   PetscCall(PetscFree((*newdm)->vectype));
    144:   PetscCall(PetscStrallocpy(dm->vectype, (char **)&(*newdm)->vectype));
    145:   PetscCall(PetscFree((*newdm)->mattype));
    146:   PetscCall(PetscStrallocpy(dm->mattype, (char **)&(*newdm)->mattype));
    147:   PetscCall(DMGetDimension(dm, &dim));
    148:   PetscCall(DMSetDimension(*newdm, dim));
    149:   PetscTryTypeMethod(dm, clone, newdm);
    150:   (*newdm)->setupcalled = dm->setupcalled;
    151:   PetscCall(DMGetPointSF(dm, &sf));
    152:   PetscCall(DMSetPointSF(*newdm, sf));
    153:   PetscCall(DMGetApplicationContext(dm, &ctx));
    154:   PetscCall(DMSetApplicationContext(*newdm, ctx));
    155:   PetscCall(DMReorderSectionGetDefault(dm, &flg));
    156:   PetscCall(DMReorderSectionSetDefault(*newdm, flg));
    157:   PetscCall(DMReorderSectionGetType(dm, &otype));
    158:   PetscCall(DMReorderSectionSetType(*newdm, otype));
    159:   for (i = 0; i < 2; ++i) {
    160:     if (dm->coordinates[i].dm) {
    161:       DM           ncdm;
    162:       PetscSection cs;
    163:       PetscInt     pEnd = -1, pEndMax = -1;

    165:       PetscCall(DMGetLocalSection(dm->coordinates[i].dm, &cs));
    166:       if (cs) PetscCall(PetscSectionGetChart(cs, NULL, &pEnd));
    167:       PetscCallMPI(MPIU_Allreduce(&pEnd, &pEndMax, 1, MPIU_INT, MPI_MAX, PetscObjectComm((PetscObject)dm)));
    168:       if (pEndMax >= 0) {
    169:         PetscCall(DMClone(dm->coordinates[i].dm, &ncdm));
    170:         PetscCall(DMCopyDisc(dm->coordinates[i].dm, ncdm));
    171:         PetscCall(DMSetLocalSection(ncdm, cs));
    172:         if (dm->coordinates[i].dm->periodic.setup) {
    173:           ncdm->periodic.setup = dm->coordinates[i].dm->periodic.setup;
    174:           PetscCall(ncdm->periodic.setup(ncdm));
    175:         }
    176:         if (i) PetscCall(DMSetCellCoordinateDM(*newdm, ncdm));
    177:         else PetscCall(DMSetCoordinateDM(*newdm, ncdm));
    178:         PetscCall(DMDestroy(&ncdm));
    179:       }
    180:     }
    181:   }
    182:   PetscCall(DMGetCoordinateDim(dm, &cdim));
    183:   PetscCall(DMSetCoordinateDim(*newdm, cdim));
    184:   PetscCall(DMGetCoordinatesLocal(dm, &coords));
    185:   if (coords) {
    186:     PetscCall(DMSetCoordinatesLocal(*newdm, coords));
    187:   } else {
    188:     PetscCall(DMGetCoordinates(dm, &coords));
    189:     if (coords) PetscCall(DMSetCoordinates(*newdm, coords));
    190:   }
    191:   PetscCall(DMGetSparseLocalize(dm, &sparse));
    192:   PetscCall(DMSetSparseLocalize(*newdm, sparse));
    193:   PetscCall(DMGetCellCoordinatesLocal(dm, &coords));
    194:   if (coords) {
    195:     PetscCall(DMSetCellCoordinatesLocal(*newdm, coords));
    196:   } else {
    197:     PetscCall(DMGetCellCoordinates(dm, &coords));
    198:     if (coords) PetscCall(DMSetCellCoordinates(*newdm, coords));
    199:   }
    200:   {
    201:     const PetscReal *maxCell, *Lstart, *L;

    203:     PetscCall(DMGetPeriodicity(dm, &maxCell, &Lstart, &L));
    204:     PetscCall(DMSetPeriodicity(*newdm, maxCell, Lstart, L));
    205:   }
    206:   {
    207:     PetscBool useCone, useClosure;

    209:     PetscCall(DMGetAdjacency(dm, PETSC_DEFAULT, &useCone, &useClosure));
    210:     PetscCall(DMSetAdjacency(*newdm, PETSC_DEFAULT, useCone, useClosure));
    211:   }
    212:   PetscFunctionReturn(PETSC_SUCCESS);
    213: }

    215: /*@
    216:   DMSetVecType - Sets the type of vector to be created with `DMCreateLocalVector()` and `DMCreateGlobalVector()`

    218:   Logically Collective

    220:   Input Parameters:
    221: + dm    - initial distributed array
    222: - ctype - the vector type, for example `VECSTANDARD`, `VECCUDA`, or `VECVIENNACL`

    224:   Options Database Key:
    225: . -dm_vec_type ctype - the type of vector to create

    227:   Level: intermediate

    229: .seealso: [](ch_dmbase), `DM`, `DMCreate()`, `DMDestroy()`, `DMDAInterpolationType`, `VecType`, `DMGetVecType()`, `DMSetMatType()`, `DMGetMatType()`,
    230:           `VECSTANDARD`, `VECCUDA`, `VECVIENNACL`, `DMCreateLocalVector()`, `DMCreateGlobalVector()`
    231: @*/
    232: PetscErrorCode DMSetVecType(DM dm, VecType ctype)
    233: {
    234:   char *tmp;

    236:   PetscFunctionBegin;
    238:   PetscAssertPointer(ctype, 2);
    239:   tmp = (char *)dm->vectype;
    240:   PetscCall(PetscStrallocpy(ctype, (char **)&dm->vectype));
    241:   PetscCall(PetscFree(tmp));
    242:   PetscFunctionReturn(PETSC_SUCCESS);
    243: }

    245: /*@
    246:   DMGetVecType - Gets the type of vector created with `DMCreateLocalVector()` and `DMCreateGlobalVector()`

    248:   Logically Collective

    250:   Input Parameter:
    251: . da - initial distributed array

    253:   Output Parameter:
    254: . ctype - the vector type

    256:   Level: intermediate

    258: .seealso: [](ch_dmbase), `DM`, `DMCreate()`, `DMDestroy()`, `DMDAInterpolationType`, `VecType`, `DMSetMatType()`, `DMGetMatType()`, `DMSetVecType()`
    259: @*/
    260: PetscErrorCode DMGetVecType(DM da, VecType *ctype)
    261: {
    262:   PetscFunctionBegin;
    264:   *ctype = da->vectype;
    265:   PetscFunctionReturn(PETSC_SUCCESS);
    266: }

    268: /*@
    269:   VecGetDM - Gets the `DM` defining the data layout of the vector

    271:   Not Collective

    273:   Input Parameter:
    274: . v - The `Vec`

    276:   Output Parameter:
    277: . dm - The `DM`

    279:   Level: intermediate

    281:   Note:
    282:   A `Vec` may not have a `DM` associated with it.

    284: .seealso: [](ch_dmbase), `DM`, `VecSetDM()`, `DMGetLocalVector()`, `DMGetGlobalVector()`, `DMSetVecType()`
    285: @*/
    286: PetscErrorCode VecGetDM(Vec v, DM *dm)
    287: {
    288:   PetscFunctionBegin;
    290:   PetscAssertPointer(dm, 2);
    291:   PetscCall(PetscObjectQuery((PetscObject)v, "__PETSc_dm", (PetscObject *)dm));
    292:   PetscFunctionReturn(PETSC_SUCCESS);
    293: }

    295: /*@
    296:   VecSetDM - Sets the `DM` defining the data layout of the vector.

    298:   Not Collective

    300:   Input Parameters:
    301: + v  - The `Vec`
    302: - dm - The `DM`

    304:   Level: developer

    306:   Notes:
    307:   This is rarely used, generally one uses `DMGetLocalVector()` or  `DMGetGlobalVector()` to create a vector associated with a given `DM`

    309:   This is NOT the same as `DMCreateGlobalVector()` since it does not change the view methods or perform other customization, but merely sets the `DM` member.

    311: .seealso: [](ch_dmbase), `DM`, `VecGetDM()`, `DMGetLocalVector()`, `DMGetGlobalVector()`, `DMSetVecType()`
    312: @*/
    313: PetscErrorCode VecSetDM(Vec v, DM dm)
    314: {
    315:   PetscFunctionBegin;
    318:   PetscCall(PetscObjectCompose((PetscObject)v, "__PETSc_dm", (PetscObject)dm));
    319:   PetscFunctionReturn(PETSC_SUCCESS);
    320: }

    322: /*@
    323:   DMSetISColoringType - Sets the type of coloring, `IS_COLORING_GLOBAL` or `IS_COLORING_LOCAL` that is created by the `DM`

    325:   Logically Collective

    327:   Input Parameters:
    328: + dm    - the `DM` context
    329: - ctype - the matrix type

    331:   Options Database Key:
    332: . -dm_is_coloring_type (global|local) - see `ISColoringType`

    334:   Level: intermediate

    336: .seealso: [](ch_dmbase), `DM`, `DMDACreate1d()`, `DMDACreate2d()`, `DMDACreate3d()`, `DMCreateMatrix()`, `DMCreateMassMatrix()`, `DMSetMatrixPreallocateOnly()`, `MatType`, `DMGetMatType()`,
    337:           `DMGetISColoringType()`, `ISColoringType`, `IS_COLORING_GLOBAL`, `IS_COLORING_LOCAL`
    338: @*/
    339: PetscErrorCode DMSetISColoringType(DM dm, ISColoringType ctype)
    340: {
    341:   PetscFunctionBegin;
    343:   dm->coloringtype = ctype;
    344:   PetscFunctionReturn(PETSC_SUCCESS);
    345: }

    347: /*@
    348:   DMGetISColoringType - Gets the type of coloring, `IS_COLORING_GLOBAL` or `IS_COLORING_LOCAL` that is created by the `DM`

    350:   Logically Collective

    352:   Input Parameter:
    353: . dm - the `DM` context

    355:   Output Parameter:
    356: . ctype - the matrix type

    358:   Level: intermediate

    360: .seealso: [](ch_dmbase), `DM`, `DMDACreate1d()`, `DMDACreate2d()`, `DMDACreate3d()`, `DMCreateMatrix()`, `DMCreateMassMatrix()`, `DMSetMatrixPreallocateOnly()`, `MatType`, `DMGetMatType()`,
    361:           `ISColoringType`, `IS_COLORING_GLOBAL`, `IS_COLORING_LOCAL`
    362: @*/
    363: PetscErrorCode DMGetISColoringType(DM dm, ISColoringType *ctype)
    364: {
    365:   PetscFunctionBegin;
    367:   *ctype = dm->coloringtype;
    368:   PetscFunctionReturn(PETSC_SUCCESS);
    369: }

    371: /*@
    372:   DMSetMatType - Sets the type of matrix created with `DMCreateMatrix()`

    374:   Logically Collective

    376:   Input Parameters:
    377: + dm    - the `DM` context
    378: - ctype - the matrix type, for example `MATMPIAIJ`

    380:   Options Database Key:
    381: . -dm_mat_type ctype - the type of the matrix to create, see `MatType`

    383:   Level: intermediate

    385: .seealso: [](ch_dmbase), `DM`, `MatType`, `DMDACreate1d()`, `DMDACreate2d()`, `DMDACreate3d()`, `DMCreateMatrix()`, `DMCreateMassMatrix()`, `DMSetMatrixPreallocateOnly()`, `DMGetMatType()`, `DMCreateGlobalVector()`, `DMCreateLocalVector()`
    386: @*/
    387: PetscErrorCode DMSetMatType(DM dm, MatType ctype)
    388: {
    389:   char *tmp;

    391:   PetscFunctionBegin;
    393:   PetscAssertPointer(ctype, 2);
    394:   tmp = (char *)dm->mattype;
    395:   PetscCall(PetscStrallocpy(ctype, (char **)&dm->mattype));
    396:   PetscCall(PetscFree(tmp));
    397:   PetscFunctionReturn(PETSC_SUCCESS);
    398: }

    400: /*@
    401:   DMGetMatType - Gets the type of matrix that would be created with `DMCreateMatrix()`

    403:   Logically Collective

    405:   Input Parameter:
    406: . dm - the `DM` context

    408:   Output Parameter:
    409: . ctype - the matrix type

    411:   Level: intermediate

    413: .seealso: [](ch_dmbase), `DM`, `DMDACreate1d()`, `DMDACreate2d()`, `DMDACreate3d()`, `DMCreateMatrix()`, `DMCreateMassMatrix()`, `DMSetMatrixPreallocateOnly()`, `MatType`, `DMSetMatType()`
    414: @*/
    415: PetscErrorCode DMGetMatType(DM dm, MatType *ctype)
    416: {
    417:   PetscFunctionBegin;
    419:   *ctype = dm->mattype;
    420:   PetscFunctionReturn(PETSC_SUCCESS);
    421: }

    423: /*@
    424:   MatGetDM - Gets the `DM` defining the data layout of the matrix

    426:   Not Collective

    428:   Input Parameter:
    429: . A - The `Mat`

    431:   Output Parameter:
    432: . dm - The `DM`

    434:   Level: intermediate

    436:   Note:
    437:   A matrix may not have a `DM` associated with it

    439:   Developer Note:
    440:   Since the `Mat` class doesn't know about the `DM` class the `DM` object is associated with the `Mat` through a `PetscObjectCompose()` operation

    442: .seealso: [](ch_dmbase), `DM`, `MatSetDM()`, `DMCreateMatrix()`, `DMSetMatType()`
    443: @*/
    444: PetscErrorCode MatGetDM(Mat A, DM *dm)
    445: {
    446:   PetscFunctionBegin;
    448:   PetscAssertPointer(dm, 2);
    449:   PetscCall(PetscObjectQuery((PetscObject)A, "__PETSc_dm", (PetscObject *)dm));
    450:   PetscFunctionReturn(PETSC_SUCCESS);
    451: }

    453: /*@
    454:   MatSetDM - Sets the `DM` defining the data layout of the matrix

    456:   Not Collective

    458:   Input Parameters:
    459: + A  - The `Mat`
    460: - dm - The `DM`

    462:   Level: developer

    464:   Note:
    465:   This is rarely used in practice, rather `DMCreateMatrix()` is used to create a matrix associated with a particular `DM`

    467:   Developer Note:
    468:   Since the `Mat` class doesn't know about the `DM` class the `DM` object is associated with
    469:   the `Mat` through a `PetscObjectCompose()` operation

    471: .seealso: [](ch_dmbase), `DM`, `MatGetDM()`, `DMCreateMatrix()`, `DMSetMatType()`
    472: @*/
    473: PetscErrorCode MatSetDM(Mat A, DM dm)
    474: {
    475:   PetscFunctionBegin;
    478:   PetscCall(PetscObjectCompose((PetscObject)A, "__PETSc_dm", (PetscObject)dm));
    479:   PetscFunctionReturn(PETSC_SUCCESS);
    480: }

    482: /*@
    483:   DMSetOptionsPrefix - Sets the prefix prepended to all option names when searching through the options database

    485:   Logically Collective

    487:   Input Parameters:
    488: + dm     - the `DM` context
    489: - prefix - the prefix to prepend

    491:   Level: advanced

    493:   Note:
    494:   A hyphen (-) must NOT be given at the beginning of the prefix name.
    495:   The first character of all runtime options is AUTOMATICALLY the hyphen.

    497: .seealso: [](ch_dmbase), `DM`, `PetscObjectSetOptionsPrefix()`, `DMSetFromOptions()`
    498: @*/
    499: PetscErrorCode DMSetOptionsPrefix(DM dm, const char prefix[])
    500: {
    501:   PetscFunctionBegin;
    503:   PetscCall(PetscObjectSetOptionsPrefix((PetscObject)dm, prefix));
    504:   if (dm->sf) PetscCall(PetscObjectSetOptionsPrefix((PetscObject)dm->sf, prefix));
    505:   if (dm->sectionSF) PetscCall(PetscObjectSetOptionsPrefix((PetscObject)dm->sectionSF, prefix));
    506:   PetscFunctionReturn(PETSC_SUCCESS);
    507: }

    509: /*@
    510:   DMAppendOptionsPrefix - Appends an additional string to an already existing prefix used for searching for
    511:   `DM` options in the options database.

    513:   Logically Collective

    515:   Input Parameters:
    516: + dm     - the `DM` context
    517: - prefix - the string to append to the current prefix

    519:   Level: advanced

    521:   Note:
    522:   If the `DM` does not currently have an options prefix then this value is used alone as the prefix as if `DMSetOptionsPrefix()` had been called.
    523:   A hyphen (-) must NOT be given at the beginning of the prefix name.
    524:   The first character of all runtime options is AUTOMATICALLY the hyphen.

    526: .seealso: [](ch_dmbase), `DM`, `DMSetOptionsPrefix()`, `DMGetOptionsPrefix()`, `PetscObjectAppendOptionsPrefix()`, `DMSetFromOptions()`
    527: @*/
    528: PetscErrorCode DMAppendOptionsPrefix(DM dm, const char prefix[])
    529: {
    530:   PetscFunctionBegin;
    532:   PetscCall(PetscObjectAppendOptionsPrefix((PetscObject)dm, prefix));
    533:   PetscFunctionReturn(PETSC_SUCCESS);
    534: }

    536: /*@
    537:   DMGetOptionsPrefix - Gets the prefix used for searching for all
    538:   DM options in the options database.

    540:   Not Collective

    542:   Input Parameter:
    543: . dm - the `DM` context

    545:   Output Parameter:
    546: . prefix - pointer to the prefix string used is returned

    548:   Level: advanced

    550: .seealso: [](ch_dmbase), `DM`, `DMSetOptionsPrefix()`, `DMAppendOptionsPrefix()`, `DMSetFromOptions()`
    551: @*/
    552: PetscErrorCode DMGetOptionsPrefix(DM dm, const char *prefix[])
    553: {
    554:   PetscFunctionBegin;
    556:   PetscCall(PetscObjectGetOptionsPrefix((PetscObject)dm, prefix));
    557:   PetscFunctionReturn(PETSC_SUCCESS);
    558: }

    560: static PetscErrorCode DMCountNonCyclicReferences_Internal(DM dm, PetscBool recurseCoarse, PetscBool recurseFine, PetscInt *ncrefct)
    561: {
    562:   PetscInt refct = ((PetscObject)dm)->refct;

    564:   PetscFunctionBegin;
    565:   *ncrefct = 0;
    566:   if (dm->coarseMesh && dm->coarseMesh->fineMesh == dm) {
    567:     refct--;
    568:     if (recurseCoarse) {
    569:       PetscInt coarseCount;

    571:       PetscCall(DMCountNonCyclicReferences_Internal(dm->coarseMesh, PETSC_TRUE, PETSC_FALSE, &coarseCount));
    572:       refct += coarseCount;
    573:     }
    574:   }
    575:   if (dm->fineMesh && dm->fineMesh->coarseMesh == dm) {
    576:     refct--;
    577:     if (recurseFine) {
    578:       PetscInt fineCount;

    580:       PetscCall(DMCountNonCyclicReferences_Internal(dm->fineMesh, PETSC_FALSE, PETSC_TRUE, &fineCount));
    581:       refct += fineCount;
    582:     }
    583:   }
    584:   *ncrefct = refct;
    585:   PetscFunctionReturn(PETSC_SUCCESS);
    586: }

    588: /* Generic wrapper for DMCountNonCyclicReferences_Internal() */
    589: PetscErrorCode DMCountNonCyclicReferences(PetscObject dm, PetscInt *ncrefct)
    590: {
    591:   PetscFunctionBegin;
    592:   PetscCall(DMCountNonCyclicReferences_Internal((DM)dm, PETSC_TRUE, PETSC_TRUE, ncrefct));
    593:   PetscFunctionReturn(PETSC_SUCCESS);
    594: }

    596: PetscErrorCode DMDestroyLabelLinkList_Internal(DM dm)
    597: {
    598:   DMLabelLink next = dm->labels;

    600:   PetscFunctionBegin;
    601:   /* destroy the labels */
    602:   while (next) {
    603:     DMLabelLink tmp = next->next;

    605:     if (next->label == dm->depthLabel) dm->depthLabel = NULL;
    606:     if (next->label == dm->celltypeLabel) dm->celltypeLabel = NULL;
    607:     PetscCall(DMLabelDestroy(&next->label));
    608:     PetscCall(PetscFree(next));
    609:     next = tmp;
    610:   }
    611:   dm->labels = NULL;
    612:   PetscFunctionReturn(PETSC_SUCCESS);
    613: }

    615: PetscErrorCode DMDestroyCoordinates_Internal(DMCoordinates *c)
    616: {
    617:   PetscFunctionBegin;
    618:   c->dim = PETSC_DEFAULT;
    619:   PetscCall(DMDestroy(&c->dm));
    620:   PetscCall(VecDestroy(&c->x));
    621:   PetscCall(VecDestroy(&c->xl));
    622:   PetscCall(DMFieldDestroy(&c->field));
    623:   PetscFunctionReturn(PETSC_SUCCESS);
    624: }

    626: /*@
    627:   DMDestroy - Destroys a `DM`.

    629:   Collective

    631:   Input Parameter:
    632: . dm - the `DM` object to destroy

    634:   Level: developer

    636: .seealso: [](ch_dmbase), `DM`, `DMCreate()`, `DMType`, `DMSetType()`, `DMView()`, `DMCreateGlobalVector()`, `DMCreateInterpolation()`, `DMCreateColoring()`, `DMCreateMatrix()`
    637: @*/
    638: PetscErrorCode DMDestroy(DM *dm)
    639: {
    640:   PetscInt cnt;

    642:   PetscFunctionBegin;
    643:   if (!*dm) PetscFunctionReturn(PETSC_SUCCESS);

    646:   /* count all non-cyclic references in the doubly-linked list of coarse<->fine meshes */
    647:   PetscCall(DMCountNonCyclicReferences_Internal(*dm, PETSC_TRUE, PETSC_TRUE, &cnt));
    648:   --((PetscObject)*dm)->refct;
    649:   if (--cnt > 0) {
    650:     *dm = NULL;
    651:     PetscFunctionReturn(PETSC_SUCCESS);
    652:   }
    653:   if (((PetscObject)*dm)->refct < 0) PetscFunctionReturn(PETSC_SUCCESS);
    654:   ((PetscObject)*dm)->refct = 0;

    656:   PetscCall(DMClearGlobalVectors(*dm));
    657:   PetscCall(DMClearLocalVectors(*dm));
    658:   PetscCall(DMClearNamedGlobalVectors(*dm));
    659:   PetscCall(DMClearNamedLocalVectors(*dm));

    661:   /* Destroy the list of hooks */
    662:   {
    663:     DMCoarsenHookLink link, next;
    664:     for (link = (*dm)->coarsenhook; link; link = next) {
    665:       next = link->next;
    666:       PetscCall(PetscFree(link));
    667:     }
    668:     (*dm)->coarsenhook = NULL;
    669:   }
    670:   {
    671:     DMRefineHookLink link, next;
    672:     for (link = (*dm)->refinehook; link; link = next) {
    673:       next = link->next;
    674:       PetscCall(PetscFree(link));
    675:     }
    676:     (*dm)->refinehook = NULL;
    677:   }
    678:   {
    679:     DMSubDomainHookLink link, next;
    680:     for (link = (*dm)->subdomainhook; link; link = next) {
    681:       next = link->next;
    682:       PetscCall(PetscFree(link));
    683:     }
    684:     (*dm)->subdomainhook = NULL;
    685:   }
    686:   {
    687:     DMGlobalToLocalHookLink link, next;
    688:     for (link = (*dm)->gtolhook; link; link = next) {
    689:       next = link->next;
    690:       PetscCall(PetscFree(link));
    691:     }
    692:     (*dm)->gtolhook = NULL;
    693:   }
    694:   {
    695:     DMLocalToGlobalHookLink link, next;
    696:     for (link = (*dm)->ltoghook; link; link = next) {
    697:       next = link->next;
    698:       PetscCall(PetscFree(link));
    699:     }
    700:     (*dm)->ltoghook = NULL;
    701:   }
    702:   /* Destroy the work arrays */
    703:   {
    704:     DMWorkLink link, next;
    705:     PetscCheck(!(*dm)->workout, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Work array still checked out %p %p", (void *)(*dm)->workout, (*dm)->workout->mem);
    706:     for (link = (*dm)->workin; link; link = next) {
    707:       next = link->next;
    708:       PetscCall(PetscFree(link->mem));
    709:       PetscCall(PetscFree(link));
    710:     }
    711:     (*dm)->workin = NULL;
    712:   }
    713:   /* destroy the labels */
    714:   PetscCall(DMDestroyLabelLinkList_Internal(*dm));
    715:   /* destroy the fields */
    716:   PetscCall(DMClearFields(*dm));
    717:   /* destroy the boundaries */
    718:   {
    719:     DMBoundary next = (*dm)->boundary;
    720:     while (next) {
    721:       DMBoundary b = next;

    723:       next = b->next;
    724:       PetscCall(PetscFree(b));
    725:     }
    726:   }

    728:   PetscCall(PetscObjectDestroy(&(*dm)->dmksp));
    729:   PetscCall(PetscObjectDestroy(&(*dm)->dmsnes));
    730:   PetscCall(PetscObjectDestroy(&(*dm)->dmts));

    732:   if ((*dm)->ctx && (*dm)->ctxdestroy) PetscCall((*(*dm)->ctxdestroy)(&(*dm)->ctx));
    733:   PetscCall(MatFDColoringDestroy(&(*dm)->fd));
    734:   PetscCall(ISLocalToGlobalMappingDestroy(&(*dm)->ltogmap));
    735:   PetscCall(PetscFree((*dm)->vectype));
    736:   PetscCall(PetscFree((*dm)->mattype));

    738:   PetscCall(PetscSectionDestroy(&(*dm)->localSection));
    739:   PetscCall(PetscSectionDestroy(&(*dm)->globalSection));
    740:   PetscCall(PetscFree((*dm)->reorderSectionType));
    741:   PetscCall(PetscLayoutDestroy(&(*dm)->map));
    742:   PetscCall(PetscSectionDestroy(&(*dm)->defaultConstraint.section));
    743:   PetscCall(MatDestroy(&(*dm)->defaultConstraint.mat));
    744:   PetscCall(PetscSFDestroy(&(*dm)->sf));
    745:   PetscCall(PetscSFDestroy(&(*dm)->sectionSF));
    746:   PetscCall(PetscSFDestroy(&(*dm)->sfNatural));
    747:   PetscCall(PetscObjectDereference((PetscObject)(*dm)->sfMigration));
    748:   PetscCall(DMClearAuxiliaryVec(*dm));
    749:   PetscCall(PetscHMapAuxDestroy(&(*dm)->auxData));
    750:   if ((*dm)->coarseMesh && (*dm)->coarseMesh->fineMesh == *dm) PetscCall(DMSetFineDM((*dm)->coarseMesh, NULL));

    752:   PetscCall(DMDestroy(&(*dm)->coarseMesh));
    753:   if ((*dm)->fineMesh && (*dm)->fineMesh->coarseMesh == *dm) PetscCall(DMSetCoarseDM((*dm)->fineMesh, NULL));
    754:   PetscCall(DMDestroy(&(*dm)->fineMesh));
    755:   PetscCall(PetscFree((*dm)->Lstart));
    756:   PetscCall(PetscFree((*dm)->L));
    757:   PetscCall(PetscFree((*dm)->maxCell));
    758:   PetscCall(PetscFree2((*dm)->nullspaceConstructors, (*dm)->nearnullspaceConstructors));
    759:   PetscCall(DMDestroyCoordinates_Internal(&(*dm)->coordinates[0]));
    760:   PetscCall(DMDestroyCoordinates_Internal(&(*dm)->coordinates[1]));
    761:   if ((*dm)->transformDestroy) PetscCall((*(*dm)->transformDestroy)(*dm, (*dm)->transformCtx));
    762:   PetscCall(DMDestroy(&(*dm)->transformDM));
    763:   PetscCall(VecDestroy(&(*dm)->transform));
    764:   for (PetscInt i = 0; i < (*dm)->periodic.num_affines; i++) {
    765:     PetscCall(VecScatterDestroy(&(*dm)->periodic.affine_to_local[i]));
    766:     PetscCall(VecDestroy(&(*dm)->periodic.affine[i]));
    767:   }
    768:   if ((*dm)->periodic.num_affines > 0) PetscCall(PetscFree2((*dm)->periodic.affine_to_local, (*dm)->periodic.affine));

    770:   PetscCall(DMClearDS(*dm));
    771:   PetscCall(DMDestroy(&(*dm)->dmBC));
    772:   /* if memory was published with SAWs then destroy it */
    773:   PetscCall(PetscObjectSAWsViewOff((PetscObject)*dm));

    775:   PetscTryTypeMethod(*dm, destroy);
    776:   PetscCall(DMMonitorCancel(*dm));
    777:   PetscCall(DMCeedDestroy(&(*dm)->dmceed));
    778: #ifdef PETSC_HAVE_LIBCEED
    779:   PetscCallCEED(CeedElemRestrictionDestroy(&(*dm)->ceedERestrict));
    780:   PetscCallCEED(CeedDestroy(&(*dm)->ceed));
    781: #endif
    782:   /* We do not destroy (*dm)->data here so that we can reference count backend objects */
    783:   PetscCall(PetscHeaderDestroy(dm));
    784:   PetscFunctionReturn(PETSC_SUCCESS);
    785: }

    787: /*@
    788:   DMSetUp - sets up the data structures inside a `DM` object

    790:   Collective

    792:   Input Parameter:
    793: . dm - the `DM` object to setup

    795:   Level: intermediate

    797:   Note:
    798:   This is usually called after various parameter setting operations and `DMSetFromOptions()` are called on the `DM`

    800: .seealso: [](ch_dmbase), `DM`, `DMCreate()`, `DMSetType()`, `DMView()`, `DMCreateGlobalVector()`, `DMCreateInterpolation()`, `DMCreateColoring()`, `DMCreateMatrix()`
    801: @*/
    802: PetscErrorCode DMSetUp(DM dm)
    803: {
    804:   PetscFunctionBegin;
    806:   if (dm->setupcalled) PetscFunctionReturn(PETSC_SUCCESS);
    807:   PetscTryTypeMethod(dm, setup);
    808:   dm->setupcalled = PETSC_TRUE;
    809:   PetscFunctionReturn(PETSC_SUCCESS);
    810: }

    812: /*@
    813:   DMSetFromOptions - sets parameters in a `DM` from the options database

    815:   Collective

    817:   Input Parameter:
    818: . dm - the `DM` object to set options for

    820:   Options Database Keys:
    821: + -dm_preallocate_only (true|false)                  - Only preallocate the matrix for `DMCreateMatrix()` and `DMCreateMassMatrix()`, but do not fill it with zeros
    822: . -dm_vec_type type                                  - type of vector to create inside `DM`
    823: . -dm_mat_type type                                  - type of matrix to create inside `DM`
    824: . -dm_is_coloring_type (global|local)                - see `ISColoringType`
    825: . -dm_bind_below n                                   - bind (force execution on CPU) for `Vec` and `Mat` objects with local size (number of vector entries or matrix rows) below n; currently only supported for `DMDA`
    826: . -dm_plex_option_phases ph0_, ph1_, ...             - List of prefixes for option processing phases
    827: . -dm_plex_filename str                              - File containing a mesh
    828: . -dm_plex_boundary_filename str                     - File containing a mesh boundary
    829: . -dm_plex_name str                                  - Name of the mesh in the file
    830: . -dm_plex_shape shape                               - The domain shape, such as `BOX`, `SPHERE`, etc.
    831: . -dm_plex_cell ct                                   - Cell shape
    832: . -dm_plex_reference_cell_domain (true|false)        - Use a reference cell domain
    833: . -dm_plex_dim dim                                   - Set the topological dimension
    834: . -dm_plex_simplex (true|false)                      - `PETSC_TRUE` for simplex elements, `PETSC_FALSE` for tensor elements
    835: . -dm_plex_interpolate (true|false)                  - `PETSC_TRUE` turns on topological interpolation (creating edges and faces)
    836: . -dm_plex_orient (true|false)                       - `PETSC_TRUE` turns on topological orientation (flipping edges and faces)
    837: . -dm_plex_scale sc                                  - Scale factor for mesh coordinates
    838: . -dm_coord_remap (true|false)                       - Map coordinates using a function
    839: . -dm_plex_coordinate_dim dim                        - Change the coordinate dimension of a mesh (usually given with cdm_ prefix)
    840: . -dm_coord_map mapname                              - Select a builtin coordinate map
    841: . -dm_coord_map_params p0,p1,p2,...                  - Set coordinate mapping parameters
    842: . -dm_plex_box_faces m,n,p                           - Number of faces along each dimension
    843: . -dm_plex_box_lower x,y,z                           - Specify lower-left-bottom coordinates for the box
    844: . -dm_plex_box_upper x,y,z                           - Specify upper-right-top coordinates for the box
    845: . -dm_plex_box_bd bx,by,bz                           - Specify the `DMBoundaryType` for each direction
    846: . -dm_plex_sphere_radius r                           - The sphere radius
    847: . -dm_plex_ball_radius r                             - Radius of the ball
    848: . -dm_plex_cylinder_bd bz                            - Boundary type in the z direction
    849: . -dm_plex_cylinder_num_wedges n                     - Number of wedges around the cylinder
    850: . -dm_plex_reorder order                             - Reorder the mesh using the specified algorithm
    851: . -dm_refine_pre n                                   - The number of refinements before distribution
    852: . -dm_refine_uniform_pre (true|false)                - Flag for uniform refinement before distribution
    853: . -dm_refine_volume_limit_pre v                      - The maximum cell volume after refinement before distribution
    854: . -dm_refine n                                       - The number of refinements after distribution
    855: . -dm_extrude l                                      - Activate extrusion and specify the number of layers to extrude
    856: . -dm_plex_save_transform (true|false)               - Save the `DMPlexTransform` that produced this mesh
    857: . -dm_plex_transform_extrude_thickness t             - The total thickness of extruded layers
    858: . -dm_plex_transform_extrude_use_tensor (true|false) - Use tensor cells when extruding
    859: . -dm_plex_transform_extrude_symmetric (true|false)  - Extrude layers symmetrically about the surface
    860: . -dm_plex_transform_extrude_normal n0,...,nd        - Specify the extrusion direction
    861: . -dm_plex_transform_extrude_thicknesses t0,...,tl   - Specify thickness of each layer
    862: . -dm_plex_create_fv_ghost_cells                     - Flag to create finite volume ghost cells on the boundary
    863: . -dm_plex_fv_ghost_cells_label name                 - Label name for ghost cells boundary
    864: . -dm_distribute (true|false)                        - Flag to redistribute a mesh among processes
    865: . -dm_distribute_overlap n                           - The size of the overlap halo
    866: . -dm_plex_adj_cone (true|false)                     - Set adjacency direction
    867: . -dm_plex_adj_closure (true|false)                  - Set adjacency size
    868: . -dm_plex_use_ceed (true|false)                     - Use LibCEED as the FEM backend
    869: . -dm_plex_check_symmetry (true|false)               - Check that the adjacency information in the mesh is symmetric - `DMPlexCheckSymmetry()`
    870: . -dm_plex_check_skeleton (true|false)               - Check that each cell has the correct number of vertices (only for homogeneous simplex or tensor meshes) - `DMPlexCheckSkeleton()`
    871: . -dm_plex_check_faces (true|false)                  - Check that the faces of each cell give a vertex order this is consistent with what we expect from the cell type - `DMPlexCheckFaces()`
    872: . -dm_plex_check_geometry (true|false)               - Check that cells have positive volume - `DMPlexCheckGeometry()`
    873: . -dm_plex_check_pointsf (true|false)                - Check some necessary conditions for `PointSF` - `DMPlexCheckPointSF()`
    874: . -dm_plex_check_interface_cones (true|false)        - Check points on inter-partition interfaces have conforming order of cone points - `DMPlexCheckInterfaceCones()`
    875: - -dm_plex_check_all (true|false)                    - Perform all the checks above

    877:   Level: intermediate

    879:   Note:
    880:   For some `DMType` such as `DMDA` this cannot be called after `DMSetUp()` has been called.

    882: .seealso: [](ch_dmbase), `DM`, `DMView()`, `DMCreateGlobalVector()`, `DMCreateInterpolation()`, `DMCreateColoring()`, `DMCreateMatrix()`,
    883:          `DMPlexCheckSymmetry()`, `DMPlexCheckSkeleton()`, `DMPlexCheckFaces()`, `DMPlexCheckGeometry()`, `DMPlexCheckPointSF()`, `DMPlexCheckInterfaceCones()`,
    884:          `DMSetOptionsPrefix()`, `DMType`, `DMPLEX`, `DMDA`, `DMSetUp()`
    885: @*/
    886: PetscErrorCode DMSetFromOptions(DM dm)
    887: {
    888:   char      typeName[256];
    889:   PetscBool flg;

    891:   PetscFunctionBegin;
    893:   dm->setfromoptionscalled = PETSC_TRUE;
    894:   if (dm->sf) PetscCall(PetscSFSetFromOptions(dm->sf));
    895:   if (dm->sectionSF) PetscCall(PetscSFSetFromOptions(dm->sectionSF));
    896:   if (dm->coordinates[0].dm) PetscCall(DMSetFromOptions(dm->coordinates[0].dm));
    897:   PetscObjectOptionsBegin((PetscObject)dm);
    898:   PetscCall(PetscOptionsBool("-dm_preallocate_only", "only preallocate matrix, but do not set column indices", "DMSetMatrixPreallocateOnly", dm->prealloc_only, &dm->prealloc_only, NULL));
    899:   PetscCall(PetscOptionsFList("-dm_vec_type", "Vector type used for created vectors", "DMSetVecType", VecList, dm->vectype, typeName, 256, &flg));
    900:   if (flg) PetscCall(DMSetVecType(dm, typeName));
    901:   PetscCall(PetscOptionsFList("-dm_mat_type", "Matrix type used for created matrices", "DMSetMatType", MatList, dm->mattype ? dm->mattype : typeName, typeName, sizeof(typeName), &flg));
    902:   if (flg) PetscCall(DMSetMatType(dm, typeName));
    903:   PetscCall(PetscOptionsEnum("-dm_blocking_type", "Topological point or field node blocking", "DMSetBlockingType", DMBlockingTypes, (PetscEnum)dm->blocking_type, (PetscEnum *)&dm->blocking_type, NULL));
    904:   PetscCall(PetscOptionsEnum("-dm_is_coloring_type", "Global or local coloring of Jacobian", "DMSetISColoringType", ISColoringTypes, (PetscEnum)dm->coloringtype, (PetscEnum *)&dm->coloringtype, NULL));
    905:   PetscCall(PetscOptionsInt("-dm_bind_below", "Set the size threshold (in entries) below which the Vec is bound to the CPU", "VecBindToCPU", dm->bind_below, &dm->bind_below, &flg));
    906:   PetscCall(PetscOptionsBool("-dm_ignore_perm_output", "Ignore the local section permutation on output", "DMGetOutputDM", dm->ignorePermOutput, &dm->ignorePermOutput, NULL));
    907:   PetscTryTypeMethod(dm, setfromoptions, PetscOptionsObject);
    908:   /* process any options handlers added with PetscObjectAddOptionsHandler() */
    909:   PetscCall(PetscObjectProcessOptionsHandlers((PetscObject)dm, PetscOptionsObject));
    910:   PetscOptionsEnd();
    911:   PetscFunctionReturn(PETSC_SUCCESS);
    912: }

    914: /*@
    915:   DMViewFromOptions - View a `DM` in a particular way based on a request in the options database

    917:   Collective

    919:   Input Parameters:
    920: + dm   - the `DM` object
    921: . obj  - optional object that provides the prefix for the options database (if `NULL` then the prefix in `obj` is used)
    922: - name - option string that is used to activate viewing

    924:   Options Database Key:
    925: . -name [viewertype][:...] - option name and values. See `PetscObjectViewFromOptions()` for the possible arguments

    927:   Level: intermediate

    929: .seealso: [](ch_dmbase), `DM`, `DMView()`, `PetscObjectViewFromOptions()`, `DMCreate()`
    930: @*/
    931: PetscErrorCode DMViewFromOptions(DM dm, PeOp PetscObject obj, const char name[])
    932: {
    933:   PetscFunctionBegin;
    935:   PetscCall(PetscObjectViewFromOptions((PetscObject)dm, obj, name));
    936:   PetscFunctionReturn(PETSC_SUCCESS);
    937: }

    939: /*@
    940:   DMView - Views a `DM`. Depending on the `PetscViewer` and its `PetscViewerFormat` it may print some ASCII information about the `DM` to the screen or a file or
    941:   save the `DM` in a binary file to be loaded later or create a visualization of the `DM`

    943:   Collective

    945:   Input Parameters:
    946: + dm - the `DM` object to view
    947: - v  - the viewer

    949:   Options Database Keys:
    950: + -view_pyvista_warp f                 - Warps the mesh by the active scalar with factor f
    951: . -view_pyvista_clip xl,xu,yl,yu,zl,zu - Defines the clipping box
    952: . -dm_view_draw_line_color color       - Specify the X-window color for cell borders
    953: . -dm_view_draw_cell_color color       - Specify the X-window color for cells
    954: - -dm_view_draw_affine (true|false)    - Flag to ignore high-order edges

    956:   Level: beginner

    958:   Notes:

    960:   `PetscViewer` = `PETSCVIEWERHDF5` i.e. HDF5 format can be used with `PETSC_VIEWER_HDF5_PETSC` as the `PetscViewerFormat` to save multiple `DMPLEX`
    961:   meshes in a single HDF5 file. This in turn requires one to name the `DMPLEX` object with `PetscObjectSetName()`
    962:   before saving it with `DMView()` and before loading it with `DMLoad()` for identification of the mesh object.

    964:   `PetscViewer` = `PETSCVIEWEREXODUSII` i.e. ExodusII format assumes that element blocks (mapped to "Cell sets" labels)
    965:   consists of sequentially numbered cells.

    967:   If `dm` has been distributed, only the part of the `DM` on MPI rank 0 (including "ghost" cells and vertices) will be written.

    969:   Only TRI, TET, QUAD, and HEX cells are supported in ExodusII.

    971:   `DMPLEX` only represents geometry while most post-processing software expect that a mesh also provides information on the discretization space. This function assumes that the file represents Lagrange finite elements of order 1 or 2.
    972:   The order of the mesh shall be set using `PetscViewerExodusIISetOrder()`

    974:   Variable names can be set and queried using `PetscViewerExodusII[Set/Get][Nodal/Zonal]VariableNames[s]`.

    976: .seealso: [](ch_dmbase), `DM`, `PetscViewer`, `PetscViewerFormat`, `PetscViewerSetFormat()`, `DMDestroy()`, `DMCreateGlobalVector()`, `DMCreateInterpolation()`, `DMCreateColoring()`, `DMCreateMatrix()`, `DMCreateMassMatrix()`, `DMLoad()`, `PetscObjectSetName()`
    977: @*/
    978: PetscErrorCode DMView(DM dm, PetscViewer v)
    979: {
    980:   PetscBool         isbinary;
    981:   PetscMPIInt       size;
    982:   PetscViewerFormat format;

    984:   PetscFunctionBegin;
    986:   if (!v) PetscCall(PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)dm), &v));
    988:   /* Ideally, we would like to have this test on.
    989:      However, it currently breaks socket viz via GLVis.
    990:      During DMView(parallel_mesh,glvis_viewer), each
    991:      process opens a sequential ASCII socket to visualize
    992:      the local mesh, and PetscObjectView(dm,local_socket)
    993:      is internally called inside VecView_GLVis, incurring
    994:      in an error here */
    995:   /* PetscCheckSameComm(dm,1,v,2); */
    996:   PetscCall(PetscViewerCheckWritable(v));

    998:   PetscCall(PetscLogEventBegin(DM_View, v, 0, 0, 0));
    999:   PetscCall(PetscViewerGetFormat(v, &format));
    1000:   PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)dm), &size));
    1001:   if (size == 1 && format == PETSC_VIEWER_LOAD_BALANCE) PetscFunctionReturn(PETSC_SUCCESS);
    1002:   PetscCall(PetscObjectPrintClassNamePrefixType((PetscObject)dm, v));
    1003:   PetscCall(PetscObjectTypeCompare((PetscObject)v, PETSCVIEWERBINARY, &isbinary));
    1004:   if (isbinary) {
    1005:     PetscInt classid = DM_FILE_CLASSID;
    1006:     char     type[256];

    1008:     PetscCall(PetscViewerBinaryWrite(v, &classid, 1, PETSC_INT));
    1009:     PetscCall(PetscStrncpy(type, ((PetscObject)dm)->type_name, sizeof(type)));
    1010:     PetscCall(PetscViewerBinaryWrite(v, type, 256, PETSC_CHAR));
    1011:   }
    1012:   PetscTryTypeMethod(dm, view, v);
    1013:   PetscCall(PetscLogEventEnd(DM_View, v, 0, 0, 0));
    1014:   PetscFunctionReturn(PETSC_SUCCESS);
    1015: }

    1017: /*@
    1018:   DMCreateGlobalVector - Creates a global vector from a `DM` object. A global vector is a parallel vector that has no duplicate values shared between MPI ranks,
    1019:   that is it has no ghost locations.

    1021:   Collective

    1023:   Input Parameter:
    1024: . dm - the `DM` object

    1026:   Output Parameter:
    1027: . vec - the global vector

    1029:   Level: beginner

    1031:   Note:
    1032:   PETSc `Vec` always have all zero entries when created with `DMCreateGlobalVector()` until routines such as `VecSet()` or `VecSetValues()`
    1033:   are used to change the values. There is no reason to call `VecZeroEntries()` after creation.

    1035: .seealso: [](ch_dmbase), `DM`, `Vec`, `DMCreateLocalVector()`, `DMGetGlobalVector()`, `DMDestroy()`, `DMView()`, `DMCreateInterpolation()`, `DMCreateColoring()`, `DMCreateMatrix()`,
    1036:          `DMGlobalToLocalBegin()`, `DMGlobalToLocalEnd()`
    1037: @*/
    1038: PetscErrorCode DMCreateGlobalVector(DM dm, Vec *vec)
    1039: {
    1040:   PetscFunctionBegin;
    1042:   PetscAssertPointer(vec, 2);
    1043:   PetscUseTypeMethod(dm, createglobalvector, vec);
    1044:   if (PetscDefined(USE_DEBUG)) {
    1045:     DM vdm;

    1047:     PetscCall(VecGetDM(*vec, &vdm));
    1048:     PetscCheck(vdm, PETSC_COMM_SELF, PETSC_ERR_PLIB, "DM type '%s' did not attach the DM to the vector", ((PetscObject)dm)->type_name);
    1049:   }
    1050:   PetscFunctionReturn(PETSC_SUCCESS);
    1051: }

    1053: /*@
    1054:   DMCreateLocalVector - Creates a local vector from a `DM` object.

    1056:   Not Collective

    1058:   Input Parameter:
    1059: . dm - the `DM` object

    1061:   Output Parameter:
    1062: . vec - the local vector

    1064:   Level: beginner

    1066:   Notes:
    1067:   A local vector usually has ghost locations that contain values that are owned by different MPI ranks. A global vector has no ghost locations.

    1069:   PETSc `Vec` always have all zero entries when created with `DMCreateLocalVector()` until routines such as `VecSet()` or `VecSetValues()`
    1070:   are used to change the values. There is no reason to call `VecZeroEntries()` after creation.

    1072: .seealso: [](ch_dmbase), `DM`, `Vec`, `DMCreateGlobalVector()`, `DMGetLocalVector()`, `DMDestroy()`, `DMView()`, `DMCreateInterpolation()`, `DMCreateColoring()`, `DMCreateMatrix()`,
    1073:          `DMGlobalToLocalBegin()`, `DMGlobalToLocalEnd()`
    1074: @*/
    1075: PetscErrorCode DMCreateLocalVector(DM dm, Vec *vec)
    1076: {
    1077:   PetscFunctionBegin;
    1079:   PetscAssertPointer(vec, 2);
    1080:   PetscUseTypeMethod(dm, createlocalvector, vec);
    1081:   if (PetscDefined(USE_DEBUG)) {
    1082:     DM vdm;

    1084:     PetscCall(VecGetDM(*vec, &vdm));
    1085:     PetscCheck(vdm, PETSC_COMM_SELF, PETSC_ERR_LIB, "DM type '%s' did not attach the DM to the vector", ((PetscObject)dm)->type_name);
    1086:   }
    1087:   PetscFunctionReturn(PETSC_SUCCESS);
    1088: }

    1090: /*@
    1091:   DMGetLocalToGlobalMapping - Accesses the local-to-global mapping in a `DM`.

    1093:   Collective

    1095:   Input Parameter:
    1096: . dm - the `DM` that provides the mapping

    1098:   Output Parameter:
    1099: . ltog - the mapping

    1101:   Level: advanced

    1103:   Notes:
    1104:   The global to local mapping allows one to set values into the global vector or matrix using `VecSetValuesLocal()` and `MatSetValuesLocal()`

    1106:   Vectors obtained with  `DMCreateGlobalVector()` and matrices obtained with `DMCreateMatrix()` already contain the global mapping so you do
    1107:   need to use this function with those objects.

    1109:   This mapping can then be used by `VecSetLocalToGlobalMapping()` or `MatSetLocalToGlobalMapping()`.

    1111: .seealso: [](ch_dmbase), `DM`, `DMCreateLocalVector()`, `DMCreateGlobalVector()`, `VecSetLocalToGlobalMapping()`, `MatSetLocalToGlobalMapping()`,
    1112:           `DMCreateMatrix()`
    1113: @*/
    1114: PetscErrorCode DMGetLocalToGlobalMapping(DM dm, ISLocalToGlobalMapping *ltog)
    1115: {
    1116:   PetscInt bs = -1, bsLocal[2], bsMinMax[2];

    1118:   PetscFunctionBegin;
    1120:   PetscAssertPointer(ltog, 2);
    1121:   if (!dm->ltogmap) {
    1122:     PetscSection section, sectionGlobal;

    1124:     PetscCall(DMGetLocalSection(dm, &section));
    1125:     if (section) {
    1126:       const PetscInt *cdofs;
    1127:       PetscInt       *ltog;
    1128:       PetscInt        pStart, pEnd, n, p, k, l;

    1130:       PetscCall(DMGetGlobalSection(dm, &sectionGlobal));
    1131:       PetscCall(PetscSectionGetChart(section, &pStart, &pEnd));
    1132:       PetscCall(PetscSectionGetStorageSize(section, &n));
    1133:       PetscCall(PetscMalloc1(n, &ltog)); /* We want the local+overlap size */
    1134:       for (p = pStart, l = 0; p < pEnd; ++p) {
    1135:         PetscInt bdof, cdof, dof, off, c, cind;

    1137:         /* Should probably use constrained dofs */
    1138:         PetscCall(PetscSectionGetDof(section, p, &dof));
    1139:         PetscCall(PetscSectionGetConstraintDof(section, p, &cdof));
    1140:         PetscCall(PetscSectionGetConstraintIndices(section, p, &cdofs));
    1141:         PetscCall(PetscSectionGetOffset(sectionGlobal, p, &off));
    1142:         /* If you have dofs, and constraints, and they are unequal, we set the blocksize to 1 */
    1143:         bdof = cdof && (dof - cdof) ? 1 : dof;
    1144:         if (dof) bs = bs < 0 ? bdof : PetscGCD(bs, bdof);

    1146:         for (c = 0, cind = 0; c < dof; ++c, ++l) {
    1147:           if (cind < cdof && c == cdofs[cind]) {
    1148:             ltog[l] = off < 0 ? off - c : -(off + c + 1);
    1149:             cind++;
    1150:           } else {
    1151:             ltog[l] = (off < 0 ? -(off + 1) : off) + c - cind;
    1152:           }
    1153:         }
    1154:       }
    1155:       /* Must have same blocksize on all procs (some might have no points) */
    1156:       bsLocal[0] = bs < 0 ? PETSC_INT_MAX : bs;
    1157:       bsLocal[1] = bs;
    1158:       PetscCall(PetscGlobalMinMaxInt(PetscObjectComm((PetscObject)dm), bsLocal, bsMinMax));
    1159:       if (bsMinMax[0] != bsMinMax[1]) {
    1160:         bs = 1;
    1161:       } else {
    1162:         bs = bsMinMax[0];
    1163:       }
    1164:       bs = bs < 0 ? 1 : bs;
    1165:       /* Must reduce indices by blocksize */
    1166:       if (bs > 1) {
    1167:         for (l = 0, k = 0; l < n; l += bs, ++k) {
    1168:           // Integer division of negative values truncates toward zero(!), not toward negative infinity
    1169:           ltog[k] = ltog[l] >= 0 ? ltog[l] / bs : -(-(ltog[l] + 1) / bs + 1);
    1170:         }
    1171:         n /= bs;
    1172:       }
    1173:       PetscCall(ISLocalToGlobalMappingCreate(PetscObjectComm((PetscObject)dm), bs, n, ltog, PETSC_OWN_POINTER, &dm->ltogmap));
    1174:     } else PetscUseTypeMethod(dm, getlocaltoglobalmapping);
    1175:   }
    1176:   *ltog = dm->ltogmap;
    1177:   PetscFunctionReturn(PETSC_SUCCESS);
    1178: }

    1180: /*@
    1181:   DMGetBlockSize - Gets the inherent block size associated with a `DM`

    1183:   Not Collective

    1185:   Input Parameter:
    1186: . dm - the `DM` with block structure

    1188:   Output Parameter:
    1189: . bs - the block size, 1 implies no exploitable block structure

    1191:   Level: intermediate

    1193:   Notes:
    1194:   This might be the number of degrees of freedom at each grid point for a structured grid.

    1196:   Complex `DM` that represent multiphysics or staggered grids or mixed-methods do not generally have a single inherent block size, but
    1197:   rather different locations in the vectors may have a different block size.

    1199: .seealso: [](ch_dmbase), `DM`, `ISCreateBlock()`, `VecSetBlockSize()`, `MatSetBlockSize()`, `DMGetLocalToGlobalMapping()`
    1200: @*/
    1201: PetscErrorCode DMGetBlockSize(DM dm, PetscInt *bs)
    1202: {
    1203:   PetscFunctionBegin;
    1205:   PetscAssertPointer(bs, 2);
    1206:   PetscCheck(dm->bs >= 1, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "DM does not have enough information to provide a block size yet");
    1207:   *bs = dm->bs;
    1208:   PetscFunctionReturn(PETSC_SUCCESS);
    1209: }

    1211: /*@
    1212:   DMCreateInterpolation - Gets the interpolation matrix between two `DM` objects. The resulting matrix map degrees of freedom in the vector obtained by
    1213:   `DMCreateGlobalVector()` on the coarse `DM` to similar vectors on the fine grid `DM`.

    1215:   Collective

    1217:   Input Parameters:
    1218: + dmc - the `DM` object
    1219: - dmf - the second, finer `DM` object

    1221:   Output Parameters:
    1222: + mat - the interpolation
    1223: - vec - the scaling (optional, pass `NULL` if not needed), see `DMCreateInterpolationScale()`

    1225:   Level: developer

    1227:   Notes:
    1228:   For `DMDA` objects this only works for "uniform refinement", that is the refined mesh was obtained `DMRefine()` or the coarse mesh was obtained by
    1229:   DMCoarsen(). The coordinates set into the `DMDA` are completely ignored in computing the interpolation.

    1231:   For `DMDA` objects you can use this interpolation (more precisely the interpolation from the `DMGetCoordinateDM()`) to interpolate the mesh coordinate
    1232:   vectors EXCEPT in the periodic case where it does not make sense since the coordinate vectors are not periodic.

    1234: .seealso: [](ch_dmbase), `DM`, `DMDestroy()`, `DMView()`, `DMCreateGlobalVector()`, `DMCreateColoring()`, `DMCreateMatrix()`, `DMCreateMassMatrix()`, `DMRefine()`, `DMCoarsen()`, `DMCreateRestriction()`, `DMCreateInterpolationScale()`
    1235: @*/
    1236: PetscErrorCode DMCreateInterpolation(DM dmc, DM dmf, Mat *mat, Vec *vec)
    1237: {
    1238:   PetscFunctionBegin;
    1241:   PetscAssertPointer(mat, 3);
    1242:   PetscCall(PetscLogEventBegin(DM_CreateInterpolation, dmc, dmf, 0, 0));
    1243:   PetscUseTypeMethod(dmc, createinterpolation, dmf, mat, vec);
    1244:   PetscCall(PetscLogEventEnd(DM_CreateInterpolation, dmc, dmf, 0, 0));
    1245:   PetscFunctionReturn(PETSC_SUCCESS);
    1246: }

    1248: /*@
    1249:   DMCreateInterpolationScale - Forms L = 1/(R*1) where 1 is the vector of all ones, and R is
    1250:   the transpose of the interpolation between the `DM`.

    1252:   Input Parameters:
    1253: + dac - `DM` that defines a coarse mesh
    1254: . daf - `DM` that defines a fine mesh
    1255: - mat - the restriction (or interpolation operator) from fine to coarse

    1257:   Output Parameter:
    1258: . scale - the scaled vector

    1260:   Level: advanced

    1262:   Note:
    1263:   xcoarse = diag(L)*R*xfine preserves scale and is thus suitable for state (versus residual)
    1264:   restriction. In other words xcoarse is the coarse representation of xfine.

    1266:   Developer Note:
    1267:   If the fine-scale `DMDA` has the -dm_bind_below option set to true, then `DMCreateInterpolationScale()` calls `MatSetBindingPropagates()`
    1268:   on the restriction/interpolation operator to set the bindingpropagates flag to true.

    1270: .seealso: [](ch_dmbase), `DM`, `MatRestrict()`, `MatInterpolate()`, `DMCreateInterpolation()`, `DMCreateRestriction()`, `DMCreateGlobalVector()`
    1271: @*/
    1272: PetscErrorCode DMCreateInterpolationScale(DM dac, DM daf, Mat mat, Vec *scale)
    1273: {
    1274:   Vec         fine;
    1275:   PetscScalar one = 1.0;
    1276: #if defined(PETSC_HAVE_CUDA)
    1277:   PetscBool bindingpropagates, isbound;
    1278: #endif

    1280:   PetscFunctionBegin;
    1281:   PetscCall(DMCreateGlobalVector(daf, &fine));
    1282:   PetscCall(DMCreateGlobalVector(dac, scale));
    1283:   PetscCall(VecSet(fine, one));
    1284: #if defined(PETSC_HAVE_CUDA)
    1285:   /* If the 'fine' Vec is bound to the CPU, it makes sense to bind 'mat' as well.
    1286:    * Note that we only do this for the CUDA case, right now, but if we add support for MatMultTranspose() via ViennaCL,
    1287:    * we'll need to do it for that case, too.*/
    1288:   PetscCall(VecGetBindingPropagates(fine, &bindingpropagates));
    1289:   if (bindingpropagates) {
    1290:     PetscCall(MatSetBindingPropagates(mat, PETSC_TRUE));
    1291:     PetscCall(VecBoundToCPU(fine, &isbound));
    1292:     PetscCall(MatBindToCPU(mat, isbound));
    1293:   }
    1294: #endif
    1295:   PetscCall(MatRestrict(mat, fine, *scale));
    1296:   PetscCall(VecDestroy(&fine));
    1297:   PetscCall(VecReciprocal(*scale));
    1298:   PetscFunctionReturn(PETSC_SUCCESS);
    1299: }

    1301: /*@
    1302:   DMCreateRestriction - Gets restriction matrix between two `DM` objects. The resulting matrix map degrees of freedom in the vector obtained by
    1303:   `DMCreateGlobalVector()` on the fine `DM` to similar vectors on the coarse grid `DM`.

    1305:   Collective

    1307:   Input Parameters:
    1308: + dmc - the `DM` object
    1309: - dmf - the second, finer `DM` object

    1311:   Output Parameter:
    1312: . mat - the restriction

    1314:   Level: developer

    1316:   Note:
    1317:   This only works for `DMSTAG`. For many situations either the transpose of the operator obtained with `DMCreateInterpolation()` or that
    1318:   matrix multiplied by the vector obtained with `DMCreateInterpolationScale()` provides the desired object.

    1320: .seealso: [](ch_dmbase), `DM`, `DMRestrict()`, `DMInterpolate()`, `DMDestroy()`, `DMView()`, `DMCreateGlobalVector()`, `DMCreateColoring()`, `DMCreateMatrix()`, `DMCreateMassMatrix()`, `DMRefine()`, `DMCoarsen()`, `DMCreateInterpolation()`
    1321: @*/
    1322: PetscErrorCode DMCreateRestriction(DM dmc, DM dmf, Mat *mat)
    1323: {
    1324:   PetscFunctionBegin;
    1327:   PetscAssertPointer(mat, 3);
    1328:   PetscCall(PetscLogEventBegin(DM_CreateRestriction, dmc, dmf, 0, 0));
    1329:   PetscUseTypeMethod(dmc, createrestriction, dmf, mat);
    1330:   PetscCall(PetscLogEventEnd(DM_CreateRestriction, dmc, dmf, 0, 0));
    1331:   PetscFunctionReturn(PETSC_SUCCESS);
    1332: }

    1334: /*@
    1335:   DMCreateInjection - Gets injection matrix between two `DM` objects.

    1337:   Collective

    1339:   Input Parameters:
    1340: + dac - the `DM` object
    1341: - daf - the second, finer `DM` object

    1343:   Output Parameter:
    1344: . mat - the injection

    1346:   Level: developer

    1348:   Notes:
    1349:   This is an operator that applied to a vector obtained with `DMCreateGlobalVector()` on the
    1350:   fine grid maps the values to a vector on the vector on the coarse `DM` by simply selecting
    1351:   the values on the coarse grid points. This compares to the operator obtained by
    1352:   `DMCreateRestriction()` or the transpose of the operator obtained by
    1353:   `DMCreateInterpolation()` that uses a "local weighted average" of the values around the
    1354:   coarse grid point as the coarse grid value.

    1356:   For `DMDA` objects this only works for "uniform refinement", that is the refined mesh was obtained `DMRefine()` or the coarse mesh was obtained by
    1357:   `DMCoarsen()`. The coordinates set into the `DMDA` are completely ignored in computing the injection.

    1359: .seealso: [](ch_dmbase), `DM`, `DMDestroy()`, `DMView()`, `DMCreateGlobalVector()`, `DMCreateColoring()`, `DMCreateMatrix()`, `DMCreateMassMatrix()`, `DMCreateInterpolation()`,
    1360:           `DMCreateRestriction()`, `MatRestrict()`, `MatInterpolate()`
    1361: @*/
    1362: PetscErrorCode DMCreateInjection(DM dac, DM daf, Mat *mat)
    1363: {
    1364:   PetscFunctionBegin;
    1367:   PetscAssertPointer(mat, 3);
    1368:   PetscCall(PetscLogEventBegin(DM_CreateInjection, dac, daf, 0, 0));
    1369:   PetscUseTypeMethod(dac, createinjection, daf, mat);
    1370:   PetscCall(PetscLogEventEnd(DM_CreateInjection, dac, daf, 0, 0));
    1371:   PetscFunctionReturn(PETSC_SUCCESS);
    1372: }

    1374: /*@
    1375:   DMCreateMassMatrix - Gets the mass matrix between two `DM` objects, M_ij = \int \phi_i \psi_j where the \phi are Galerkin basis functions for a
    1376:   a Galerkin finite element model on the `DM`

    1378:   Collective

    1380:   Input Parameters:
    1381: + dmc - the target `DM` object
    1382: - dmf - the source `DM` object, can be `NULL`

    1384:   Output Parameter:
    1385: . mat - the mass matrix

    1387:   Level: developer

    1389:   Notes:
    1390:   For `DMPLEX` the finite element model for the `DM` must have been already provided.

    1392:   if `dmc` is `dmf` or `NULL`, then x^t M x is an approximation to the L2 norm of the vector x which is obtained by `DMCreateGlobalVector()`

    1394: .seealso: [](ch_dmbase), `DM`, `DMCreateMassMatrixLumped()`, `DMCreateMatrix()`, `DMRefine()`, `DMCoarsen()`, `DMCreateRestriction()`, `DMCreateInterpolation()`, `DMCreateInjection()`
    1395: @*/
    1396: PetscErrorCode DMCreateMassMatrix(DM dmc, DM dmf, Mat *mat)
    1397: {
    1398:   PetscFunctionBegin;
    1400:   if (!dmf) dmf = dmc;
    1402:   PetscAssertPointer(mat, 3);
    1403:   PetscCall(PetscLogEventBegin(DM_CreateMassMatrix, dmc, dmf, 0, 0));
    1404:   PetscUseTypeMethod(dmc, createmassmatrix, dmf, mat);
    1405:   PetscCall(PetscLogEventEnd(DM_CreateMassMatrix, dmc, dmf, 0, 0));
    1406:   PetscFunctionReturn(PETSC_SUCCESS);
    1407: }

    1409: /*@
    1410:   DMCreateMassMatrixLumped - Gets the lumped mass matrix for a given `DM`

    1412:   Collective

    1414:   Input Parameter:
    1415: . dm - the `DM` object

    1417:   Output Parameters:
    1418: + llm - the local lumped mass matrix, which is a diagonal matrix, represented as a vector
    1419: - lm  - the global lumped mass matrix, which is a diagonal matrix, represented as a vector

    1421:   Level: developer

    1423:   Note:
    1424:   See `DMCreateMassMatrix()` for how to create the non-lumped version of the mass matrix.

    1426: .seealso: [](ch_dmbase), `DM`, `DMCreateMassMatrix()`, `DMCreateMatrix()`, `DMRefine()`, `DMCoarsen()`, `DMCreateRestriction()`, `DMCreateInterpolation()`, `DMCreateInjection()`
    1427: @*/
    1428: PetscErrorCode DMCreateMassMatrixLumped(DM dm, Vec *llm, Vec *lm)
    1429: {
    1430:   PetscFunctionBegin;
    1432:   if (llm) PetscAssertPointer(llm, 2);
    1433:   if (lm) PetscAssertPointer(lm, 3);
    1434:   if (llm || lm) PetscUseTypeMethod(dm, createmassmatrixlumped, llm, lm);
    1435:   PetscFunctionReturn(PETSC_SUCCESS);
    1436: }

    1438: /*@
    1439:   DMCreateGradientMatrix - Gets the gradient matrix between two `DM` objects, M_(ic)j = \int \partial_c \phi_i \psi_j where the \phi are Galerkin basis functions for a Galerkin finite element model on the `DM`

    1441:   Collective

    1443:   Input Parameters:
    1444: + dmc - the target `DM` object
    1445: - dmf - the source `DM` object, can be `NULL`

    1447:   Output Parameter:
    1448: . mat - the gradient matrix

    1450:   Level: developer

    1452:   Notes:
    1453:   For `DMPLEX` the finite element model for the `DM` must have been already provided.

    1455: .seealso: [](ch_dmbase), `DM`, `DMCreateMassMatrix()`, `DMCreateMassMatrixLumped()`, `DMCreateMatrix()`, `DMRefine()`, `DMCoarsen()`, `DMCreateRestriction()`, `DMCreateInterpolation()`, `DMCreateInjection()`
    1456: @*/
    1457: PetscErrorCode DMCreateGradientMatrix(DM dmc, DM dmf, Mat *mat)
    1458: {
    1459:   PetscFunctionBegin;
    1461:   if (!dmf) dmf = dmc;
    1463:   PetscAssertPointer(mat, 3);
    1464:   PetscUseTypeMethod(dmc, creategradientmatrix, dmf, mat);
    1465:   PetscFunctionReturn(PETSC_SUCCESS);
    1466: }

    1468: /*@
    1469:   DMCreateColoring - Gets coloring of a graph associated with the `DM`. Often the graph represents the operator matrix associated with the discretization
    1470:   of a PDE on the `DM`.

    1472:   Collective

    1474:   Input Parameters:
    1475: + dm    - the `DM` object
    1476: - ctype - `IS_COLORING_LOCAL` or `IS_COLORING_GLOBAL`

    1478:   Output Parameter:
    1479: . coloring - the coloring

    1481:   Level: developer

    1483:   Notes:
    1484:   Coloring of matrices can also be computed directly from the sparse matrix nonzero structure via the `MatColoring` object or from the mesh from which the
    1485:   matrix comes from (what this function provides). In general using the mesh produces a more optimal coloring (fewer colors).

    1487:   This produces a coloring with the distance of 2, see `MatSetColoringDistance()` which can be used for efficiently computing Jacobians with `MatFDColoringCreate()`
    1488:   For `DMDA` in three dimensions with periodic boundary conditions the number of grid points in each dimension must be divisible by 2*stencil_width + 1,
    1489:   otherwise an error will be generated.

    1491: .seealso: [](ch_dmbase), `DM`, `ISColoring`, `DMDestroy()`, `DMView()`, `DMCreateGlobalVector()`, `DMCreateInterpolation()`, `DMCreateMatrix()`, `DMCreateMassMatrix()`, `DMSetMatType()`, `MatColoring`, `MatFDColoringCreate()`
    1492: @*/
    1493: PetscErrorCode DMCreateColoring(DM dm, ISColoringType ctype, ISColoring *coloring)
    1494: {
    1495:   PetscFunctionBegin;
    1497:   PetscAssertPointer(coloring, 3);
    1498:   PetscUseTypeMethod(dm, getcoloring, ctype, coloring);
    1499:   PetscFunctionReturn(PETSC_SUCCESS);
    1500: }

    1502: /*@
    1503:   DMCreateMatrix - Creates a matrix of appropriate size and nonzero structure for a `DM`. The matrix is most commonly used to store the Jacobian
    1504:   of a discrete PDE operator.

    1506:   Collective

    1508:   Input Parameter:
    1509: . dm - the `DM` object

    1511:   Output Parameter:
    1512: . mat - the matrix

    1514:   Options Database Key:
    1515: . -dm_preallocate_only (true|false) - Only preallocate the matrix for `DMCreateMatrix()` and `DMCreateMassMatrix()`, but do not fill its nonzero structure

    1517:   Level: beginner

    1519:   Notes:
    1520:   This properly preallocates the number of nonzeros in the sparse matrix so you
    1521:   do not need to do it yourself.

    1523:   By default it also sets the nonzero structure and puts in the zero entries. To prevent setting
    1524:   the nonzero pattern call `DMSetMatrixPreallocateOnly()`

    1526:   For `DMDA`, when you call `MatView()` on this matrix it is displayed using the global natural ordering, NOT in the ordering used
    1527:   internally by PETSc.

    1529:   For `DMDA`, in general it is easiest to use `MatSetValuesStencil()` or `MatSetValuesLocal()` to put values into the matrix because
    1530:   `MatSetValues()` requires the indices for the global numbering for the `DMDA` which is complic`ated to compute

    1532: .seealso: [](ch_dmbase), `DM`, `DMDestroy()`, `DMView()`, `DMCreateGlobalVector()`, `DMCreateInterpolation()`, `DMSetMatType()`, `DMCreateMassMatrix()`
    1533: @*/
    1534: PetscErrorCode DMCreateMatrix(DM dm, Mat *mat)
    1535: {
    1536:   PetscFunctionBegin;
    1538:   PetscAssertPointer(mat, 2);
    1539:   PetscCall(MatInitializePackage());
    1540:   PetscCall(PetscLogEventBegin(DM_CreateMatrix, 0, 0, 0, 0));
    1541:   PetscUseTypeMethod(dm, creatematrix, mat);
    1542:   if (PetscDefined(USE_DEBUG)) {
    1543:     DM mdm;

    1545:     PetscCall(MatGetDM(*mat, &mdm));
    1546:     PetscCheck(mdm, PETSC_COMM_SELF, PETSC_ERR_PLIB, "DM type '%s' did not attach the DM to the matrix", ((PetscObject)dm)->type_name);
    1547:   }
    1548:   /* Handle nullspace and near nullspace */
    1549:   if (dm->Nf) {
    1550:     MatNullSpace nullSpace;
    1551:     PetscInt     Nf, f;

    1553:     PetscCall(DMGetNumFields(dm, &Nf));
    1554:     for (f = 0; f < Nf; ++f) {
    1555:       if (dm->nullspaceConstructors && dm->nullspaceConstructors[f]) {
    1556:         PetscCall((*dm->nullspaceConstructors[f])(dm, f, f, &nullSpace));
    1557:         PetscCall(MatSetNullSpace(*mat, nullSpace));
    1558:         PetscCall(MatNullSpaceDestroy(&nullSpace));
    1559:         break;
    1560:       }
    1561:     }
    1562:     for (f = 0; f < Nf; ++f) {
    1563:       if (dm->nearnullspaceConstructors && dm->nearnullspaceConstructors[f]) {
    1564:         PetscCall((*dm->nearnullspaceConstructors[f])(dm, f, f, &nullSpace));
    1565:         PetscCall(MatSetNearNullSpace(*mat, nullSpace));
    1566:         PetscCall(MatNullSpaceDestroy(&nullSpace));
    1567:       }
    1568:     }
    1569:   }
    1570:   PetscCall(PetscLogEventEnd(DM_CreateMatrix, 0, 0, 0, 0));
    1571:   PetscFunctionReturn(PETSC_SUCCESS);
    1572: }

    1574: /*@
    1575:   DMSetMatrixPreallocateSkip - When `DMCreateMatrix()` is called the matrix sizes and
    1576:   `ISLocalToGlobalMapping` will be properly set, but the data structures to store values in the
    1577:   matrices will not be preallocated.

    1579:   Logically Collective

    1581:   Input Parameters:
    1582: + dm   - the `DM`
    1583: - skip - `PETSC_TRUE` to skip preallocation

    1585:   Level: developer

    1587:   Note:
    1588:   This is most useful to reduce initialization costs when `MatSetPreallocationCOO()` and
    1589:   `MatSetValuesCOO()` will be used.

    1591: .seealso: [](ch_dmbase), `DM`, `DMCreateMatrix()`, `DMSetMatrixStructureOnly()`, `DMSetMatrixPreallocateOnly()`
    1592: @*/
    1593: PetscErrorCode DMSetMatrixPreallocateSkip(DM dm, PetscBool skip)
    1594: {
    1595:   PetscFunctionBegin;
    1597:   dm->prealloc_skip = skip;
    1598:   PetscFunctionReturn(PETSC_SUCCESS);
    1599: }

    1601: /*@
    1602:   DMSetMatrixPreallocateOnly - When `DMCreateMatrix()` is called the matrix will be properly
    1603:   preallocated but the nonzero structure and zero values will not be set.

    1605:   Logically Collective

    1607:   Input Parameters:
    1608: + dm   - the `DM`
    1609: - only - `PETSC_TRUE` if only want preallocation

    1611:   Options Database Key:
    1612: . -dm_preallocate_only - Only preallocate the matrix for `DMCreateMatrix()`, `DMCreateMassMatrix()`, but do not fill it with zeros

    1614:   Level: developer

    1616: .seealso: [](ch_dmbase), `DM`, `DMCreateMatrix()`, `DMCreateMassMatrix()`, `DMSetMatrixStructureOnly()`, `DMSetMatrixPreallocateSkip()`
    1617: @*/
    1618: PetscErrorCode DMSetMatrixPreallocateOnly(DM dm, PetscBool only)
    1619: {
    1620:   PetscFunctionBegin;
    1622:   dm->prealloc_only = only;
    1623:   PetscFunctionReturn(PETSC_SUCCESS);
    1624: }

    1626: /*@
    1627:   DMSetMatrixStructureOnly - When `DMCreateMatrix()` is called, the matrix nonzero structure will be created
    1628:   but the array for numerical values will not be allocated.

    1630:   Logically Collective

    1632:   Input Parameters:
    1633: + dm   - the `DM`
    1634: - only - `PETSC_TRUE` if you only want matrix nonzero structure

    1636:   Level: developer

    1638: .seealso: [](ch_dmbase), `DM`, `DMCreateMatrix()`, `DMSetMatrixPreallocateOnly()`, `DMSetMatrixPreallocateSkip()`
    1639: @*/
    1640: PetscErrorCode DMSetMatrixStructureOnly(DM dm, PetscBool only)
    1641: {
    1642:   PetscFunctionBegin;
    1644:   dm->structure_only = only;
    1645:   PetscFunctionReturn(PETSC_SUCCESS);
    1646: }

    1648: /*@
    1649:   DMSetBlockingType - set the blocking granularity to be used for variable block size `DMCreateMatrix()` is called

    1651:   Logically Collective

    1653:   Input Parameters:
    1654: + dm    - the `DM`
    1655: - btype - block by topological point or field node

    1657:   Options Database Key:
    1658: . -dm_blocking_type (topological_point|field_node) - use topological point blocking or field node blocking

    1660:   Level: advanced

    1662: .seealso: [](ch_dmbase), `DM`, `DMCreateMatrix()`, `MatSetVariableBlockSizes()`
    1663: @*/
    1664: PetscErrorCode DMSetBlockingType(DM dm, DMBlockingType btype)
    1665: {
    1666:   PetscFunctionBegin;
    1668:   dm->blocking_type = btype;
    1669:   PetscFunctionReturn(PETSC_SUCCESS);
    1670: }

    1672: /*@
    1673:   DMGetBlockingType - get the blocking granularity to be used for variable block size `DMCreateMatrix()` is called

    1675:   Not Collective

    1677:   Input Parameter:
    1678: . dm - the `DM`

    1680:   Output Parameter:
    1681: . btype - block by topological point or field node

    1683:   Level: advanced

    1685: .seealso: [](ch_dmbase), `DM`, `DMCreateMatrix()`, `MatSetVariableBlockSizes()`
    1686: @*/
    1687: PetscErrorCode DMGetBlockingType(DM dm, DMBlockingType *btype)
    1688: {
    1689:   PetscFunctionBegin;
    1691:   PetscAssertPointer(btype, 2);
    1692:   *btype = dm->blocking_type;
    1693:   PetscFunctionReturn(PETSC_SUCCESS);
    1694: }

    1696: /*@C
    1697:   DMGetWorkArray - Gets a work array guaranteed to be at least the input size, restore with `DMRestoreWorkArray()`

    1699:   Not Collective

    1701:   Input Parameters:
    1702: + dm    - the `DM` object
    1703: . count - The minimum size
    1704: - dtype - MPI data type, often `MPIU_REAL`, `MPIU_SCALAR`, or `MPIU_INT`)

    1706:   Output Parameter:
    1707: . mem - the work array

    1709:   Level: developer

    1711:   Notes:
    1712:   A `DM` may stash the array between instantiations so using this routine may be more efficient than calling `PetscMalloc()`

    1714:   The array may contain nonzero values

    1716: .seealso: [](ch_dmbase), `DM`, `DMDestroy()`, `DMCreate()`, `DMRestoreWorkArray()`, `PetscMalloc()`
    1717: @*/
    1718: PetscErrorCode DMGetWorkArray(DM dm, PetscInt count, MPI_Datatype dtype, void *mem)
    1719: {
    1720:   DMWorkLink  link;
    1721:   PetscMPIInt dsize;

    1723:   PetscFunctionBegin;
    1725:   PetscAssertPointer(mem, 4);
    1726:   if (!count) {
    1727:     *(void **)mem = NULL;
    1728:     PetscFunctionReturn(PETSC_SUCCESS);
    1729:   }
    1730:   if (dm->workin) {
    1731:     link       = dm->workin;
    1732:     dm->workin = dm->workin->next;
    1733:   } else {
    1734:     PetscCall(PetscNew(&link));
    1735:   }
    1736:   /* Avoid MPI_Type_size for most used datatypes
    1737:      Get size directly */
    1738:   if (dtype == MPIU_INT) dsize = sizeof(PetscInt);
    1739:   else if (dtype == MPIU_REAL) dsize = sizeof(PetscReal);
    1740: #if defined(PETSC_USE_64BIT_INDICES)
    1741:   else if (dtype == MPI_INT) dsize = sizeof(int);
    1742: #endif
    1743: #if defined(PETSC_USE_COMPLEX)
    1744:   else if (dtype == MPIU_SCALAR) dsize = sizeof(PetscScalar);
    1745: #endif
    1746:   else PetscCallMPI(MPI_Type_size(dtype, &dsize));

    1748:   if (((size_t)dsize * count) > link->bytes) {
    1749:     PetscCall(PetscFree(link->mem));
    1750:     PetscCall(PetscMalloc(dsize * count, &link->mem));
    1751:     link->bytes = dsize * count;
    1752:   }
    1753:   link->next    = dm->workout;
    1754:   dm->workout   = link;
    1755:   *(void **)mem = link->mem;
    1756:   PetscFunctionReturn(PETSC_SUCCESS);
    1757: }

    1759: /*@C
    1760:   DMRestoreWorkArray - Restores a work array obtained with `DMCreateWorkArray()`

    1762:   Not Collective

    1764:   Input Parameters:
    1765: + dm    - the `DM` object
    1766: . count - The minimum size
    1767: - dtype - MPI data type, often `MPIU_REAL`, `MPIU_SCALAR`, `MPIU_INT`

    1769:   Output Parameter:
    1770: . mem - the work array

    1772:   Level: developer

    1774:   Developer Note:
    1775:   count and dtype are ignored, they are only needed for `DMGetWorkArray()`

    1777: .seealso: [](ch_dmbase), `DM`, `DMDestroy()`, `DMCreate()`, `DMGetWorkArray()`
    1778: @*/
    1779: PetscErrorCode DMRestoreWorkArray(DM dm, PetscInt count, MPI_Datatype dtype, void *mem)
    1780: {
    1781:   DMWorkLink *p, link;

    1783:   PetscFunctionBegin;
    1784:   PetscAssertPointer(mem, 4);
    1785:   (void)count;
    1786:   (void)dtype;
    1787:   if (!*(void **)mem) PetscFunctionReturn(PETSC_SUCCESS);
    1788:   for (p = &dm->workout; (link = *p); p = &link->next) {
    1789:     if (link->mem == *(void **)mem) {
    1790:       *p            = link->next;
    1791:       link->next    = dm->workin;
    1792:       dm->workin    = link;
    1793:       *(void **)mem = NULL;
    1794:       PetscFunctionReturn(PETSC_SUCCESS);
    1795:     }
    1796:   }
    1797:   SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Array was not checked out");
    1798: }

    1800: /*@C
    1801:   DMSetNullSpaceConstructor - Provide a callback function which constructs the nullspace for a given field, defined with `DMAddField()`, when function spaces
    1802:   are joined or split, such as in `DMCreateSubDM()`

    1804:   Logically Collective; No Fortran Support

    1806:   Input Parameters:
    1807: + dm     - The `DM`
    1808: . field  - The field number for the nullspace
    1809: - nullsp - A callback to create the nullspace

    1811:   Calling sequence of `nullsp`:
    1812: + dm        - The present `DM`
    1813: . origField - The field number given above, in the original `DM`
    1814: . field     - The field number in dm
    1815: - nullSpace - The nullspace for the given field

    1817:   Level: intermediate

    1819: .seealso: [](ch_dmbase), `DM`, `DMAddField()`, `DMGetNullSpaceConstructor()`, `DMSetNearNullSpaceConstructor()`, `DMGetNearNullSpaceConstructor()`, `DMCreateSubDM()`, `DMCreateSuperDM()`
    1820: @*/
    1821: PetscErrorCode DMSetNullSpaceConstructor(DM dm, PetscInt field, PetscErrorCode (*nullsp)(DM dm, PetscInt origField, PetscInt field, MatNullSpace *nullSpace))
    1822: {
    1823:   PetscFunctionBegin;
    1825:   PetscCheck(field < dm->Nf, PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_OUTOFRANGE, "Cannot handle %" PetscInt_FMT " >= %" PetscInt_FMT " fields", field, dm->Nf);
    1826:   PetscCheck(dm->nullspaceConstructors, PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_WRONG, "Must call DMCreateDS() to setup nullspaces");
    1827:   dm->nullspaceConstructors[field] = nullsp;
    1828:   PetscFunctionReturn(PETSC_SUCCESS);
    1829: }

    1831: /*@C
    1832:   DMGetNullSpaceConstructor - Return the callback function which constructs the nullspace for a given field, defined with `DMAddField()`

    1834:   Not Collective; No Fortran Support

    1836:   Input Parameters:
    1837: + dm    - The `DM`
    1838: - field - The field number for the nullspace

    1840:   Output Parameter:
    1841: . nullsp - A callback to create the nullspace

    1843:   Calling sequence of `nullsp`:
    1844: + dm        - The present DM
    1845: . origField - The field number given above, in the original DM
    1846: . field     - The field number in dm
    1847: - nullSpace - The nullspace for the given field

    1849:   Level: intermediate

    1851: .seealso: [](ch_dmbase), `DM`, `DMAddField()`, `DMGetField()`, `DMSetNullSpaceConstructor()`, `DMSetNearNullSpaceConstructor()`, `DMGetNearNullSpaceConstructor()`, `DMCreateSubDM()`, `DMCreateSuperDM()`
    1852: @*/
    1853: PetscErrorCode DMGetNullSpaceConstructor(DM dm, PetscInt field, PetscErrorCode (**nullsp)(DM dm, PetscInt origField, PetscInt field, MatNullSpace *nullSpace))
    1854: {
    1855:   PetscFunctionBegin;
    1857:   PetscAssertPointer(nullsp, 3);
    1858:   PetscCheck(field < dm->Nf, PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_OUTOFRANGE, "Cannot handle %" PetscInt_FMT " >= %" PetscInt_FMT " fields", field, dm->Nf);
    1859:   PetscCheck(dm->nullspaceConstructors, PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_WRONG, "Must call DMCreateDS() to setup nullspaces");
    1860:   *nullsp = dm->nullspaceConstructors[field];
    1861:   PetscFunctionReturn(PETSC_SUCCESS);
    1862: }

    1864: /*@C
    1865:   DMSetNearNullSpaceConstructor - Provide a callback function which constructs the near-nullspace for a given field, defined with `DMAddField()`

    1867:   Logically Collective; No Fortran Support

    1869:   Input Parameters:
    1870: + dm     - The `DM`
    1871: . field  - The field number for the nullspace
    1872: - nullsp - A callback to create the near-nullspace

    1874:   Calling sequence of `nullsp`:
    1875: + dm        - The present `DM`
    1876: . origField - The field number given above, in the original `DM`
    1877: . field     - The field number in dm
    1878: - nullSpace - The nullspace for the given field

    1880:   Level: intermediate

    1882: .seealso: [](ch_dmbase), `DM`, `DMAddField()`, `DMGetNearNullSpaceConstructor()`, `DMSetNullSpaceConstructor()`, `DMGetNullSpaceConstructor()`, `DMCreateSubDM()`, `DMCreateSuperDM()`,
    1883:           `MatNullSpace`
    1884: @*/
    1885: PetscErrorCode DMSetNearNullSpaceConstructor(DM dm, PetscInt field, PetscErrorCode (*nullsp)(DM dm, PetscInt origField, PetscInt field, MatNullSpace *nullSpace))
    1886: {
    1887:   PetscFunctionBegin;
    1889:   PetscCheck(field < dm->Nf, PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_OUTOFRANGE, "Cannot handle %" PetscInt_FMT " >= %" PetscInt_FMT " fields", field, dm->Nf);
    1890:   PetscCheck(dm->nearnullspaceConstructors, PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_WRONG, "Must call DMCreateDS() to setup nullspaces");
    1891:   dm->nearnullspaceConstructors[field] = nullsp;
    1892:   PetscFunctionReturn(PETSC_SUCCESS);
    1893: }

    1895: /*@C
    1896:   DMGetNearNullSpaceConstructor - Return the callback function which constructs the near-nullspace for a given field, defined with `DMAddField()`

    1898:   Not Collective; No Fortran Support

    1900:   Input Parameters:
    1901: + dm    - The `DM`
    1902: - field - The field number for the nullspace

    1904:   Output Parameter:
    1905: . nullsp - A callback to create the near-nullspace

    1907:   Calling sequence of `nullsp`:
    1908: + dm        - The present `DM`
    1909: . origField - The field number given above, in the original `DM`
    1910: . field     - The field number in dm
    1911: - nullSpace - The nullspace for the given field

    1913:   Level: intermediate

    1915: .seealso: [](ch_dmbase), `DM`, `DMAddField()`, `DMGetField()`, `DMSetNearNullSpaceConstructor()`, `DMSetNullSpaceConstructor()`, `DMGetNullSpaceConstructor()`, `DMCreateSubDM()`,
    1916:           `MatNullSpace`, `DMCreateSuperDM()`
    1917: @*/
    1918: PetscErrorCode DMGetNearNullSpaceConstructor(DM dm, PetscInt field, PetscErrorCode (**nullsp)(DM dm, PetscInt origField, PetscInt field, MatNullSpace *nullSpace))
    1919: {
    1920:   PetscFunctionBegin;
    1922:   PetscAssertPointer(nullsp, 3);
    1923:   PetscCheck(field < dm->Nf, PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_OUTOFRANGE, "Cannot handle %" PetscInt_FMT " >= %" PetscInt_FMT " fields", field, dm->Nf);
    1924:   PetscCheck(dm->nearnullspaceConstructors, PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_WRONG, "Must call DMCreateDS() to setup nullspaces");
    1925:   *nullsp = dm->nearnullspaceConstructors[field];
    1926:   PetscFunctionReturn(PETSC_SUCCESS);
    1927: }

    1929: /*@C
    1930:   DMCreateFieldIS - Creates a set of `IS` objects with the global indices of dofs for each field defined with `DMAddField()`

    1932:   Not Collective; No Fortran Support

    1934:   Input Parameter:
    1935: . dm - the `DM` object

    1937:   Output Parameters:
    1938: + numFields  - The number of fields (or `NULL` if not requested)
    1939: . fieldNames - The name of each field (or `NULL` if not requested)
    1940: - fields     - The global indices for each field (or `NULL` if not requested)

    1942:   Level: intermediate

    1944:   Note:
    1945:   The user is responsible for freeing all requested arrays. In particular, every entry of `fieldNames` should be freed with
    1946:   `PetscFree()`, every entry of `fields` should be destroyed with `ISDestroy()`, and both arrays should be freed with
    1947:   `PetscFree()`.

    1949:   Developer Note:
    1950:   It is not clear why both this function and `DMCreateFieldDecomposition()` exist. Having two seems redundant and confusing. This function should
    1951:   likely be removed.

    1953: .seealso: [](ch_dmbase), `DM`, `DMAddField()`, `DMGetField()`, `DMDestroy()`, `DMView()`, `DMCreateInterpolation()`, `DMCreateColoring()`, `DMCreateMatrix()`,
    1954:           `DMCreateFieldDecomposition()`
    1955: @*/
    1956: PetscErrorCode DMCreateFieldIS(DM dm, PetscInt *numFields, char ***fieldNames, IS *fields[])
    1957: {
    1958:   PetscSection section, sectionGlobal;

    1960:   PetscFunctionBegin;
    1962:   if (numFields) {
    1963:     PetscAssertPointer(numFields, 2);
    1964:     *numFields = 0;
    1965:   }
    1966:   if (fieldNames) {
    1967:     PetscAssertPointer(fieldNames, 3);
    1968:     *fieldNames = NULL;
    1969:   }
    1970:   if (fields) {
    1971:     PetscAssertPointer(fields, 4);
    1972:     *fields = NULL;
    1973:   }
    1974:   PetscCall(DMGetLocalSection(dm, &section));
    1975:   if (section) {
    1976:     PetscInt *fieldSizes, *fieldNc, **fieldIndices;
    1977:     PetscInt  nF, f, pStart, pEnd, p;

    1979:     PetscCall(DMGetGlobalSection(dm, &sectionGlobal));
    1980:     PetscCall(PetscSectionGetNumFields(section, &nF));
    1981:     PetscCall(PetscMalloc3(nF, &fieldSizes, nF, &fieldNc, nF, &fieldIndices));
    1982:     PetscCall(PetscSectionGetChart(sectionGlobal, &pStart, &pEnd));
    1983:     for (f = 0; f < nF; ++f) {
    1984:       fieldSizes[f] = 0;
    1985:       PetscCall(PetscSectionGetFieldComponents(section, f, &fieldNc[f]));
    1986:     }
    1987:     for (p = pStart; p < pEnd; ++p) {
    1988:       PetscInt gdof;

    1990:       PetscCall(PetscSectionGetDof(sectionGlobal, p, &gdof));
    1991:       if (gdof > 0) {
    1992:         for (f = 0; f < nF; ++f) {
    1993:           PetscInt fdof, fcdof, fpdof;

    1995:           PetscCall(PetscSectionGetFieldDof(section, p, f, &fdof));
    1996:           PetscCall(PetscSectionGetFieldConstraintDof(section, p, f, &fcdof));
    1997:           fpdof = fdof - fcdof;
    1998:           if (fpdof && fpdof != fieldNc[f]) {
    1999:             /* Layout does not admit a pointwise block size */
    2000:             fieldNc[f] = 1;
    2001:           }
    2002:           fieldSizes[f] += fpdof;
    2003:         }
    2004:       }
    2005:     }
    2006:     for (f = 0; f < nF; ++f) {
    2007:       PetscCall(PetscMalloc1(fieldSizes[f], &fieldIndices[f]));
    2008:       fieldSizes[f] = 0;
    2009:     }
    2010:     for (p = pStart; p < pEnd; ++p) {
    2011:       PetscInt gdof, goff;

    2013:       PetscCall(PetscSectionGetDof(sectionGlobal, p, &gdof));
    2014:       if (gdof > 0) {
    2015:         PetscCall(PetscSectionGetOffset(sectionGlobal, p, &goff));
    2016:         for (f = 0; f < nF; ++f) {
    2017:           PetscInt fdof, fcdof, fc;

    2019:           PetscCall(PetscSectionGetFieldDof(section, p, f, &fdof));
    2020:           PetscCall(PetscSectionGetFieldConstraintDof(section, p, f, &fcdof));
    2021:           for (fc = 0; fc < fdof - fcdof; ++fc, ++fieldSizes[f]) fieldIndices[f][fieldSizes[f]] = goff++;
    2022:         }
    2023:       }
    2024:     }
    2025:     if (numFields) *numFields = nF;
    2026:     if (fieldNames) {
    2027:       PetscCall(PetscMalloc1(nF, fieldNames));
    2028:       for (f = 0; f < nF; ++f) {
    2029:         const char *fieldName;

    2031:         PetscCall(PetscSectionGetFieldName(section, f, &fieldName));
    2032:         PetscCall(PetscStrallocpy(fieldName, &(*fieldNames)[f]));
    2033:       }
    2034:     }
    2035:     if (fields) {
    2036:       PetscCall(PetscMalloc1(nF, fields));
    2037:       for (f = 0; f < nF; ++f) {
    2038:         PetscInt bs, in[2], out[2];

    2040:         PetscCall(ISCreateGeneral(PetscObjectComm((PetscObject)dm), fieldSizes[f], fieldIndices[f], PETSC_OWN_POINTER, &(*fields)[f]));
    2041:         in[0] = -fieldNc[f];
    2042:         in[1] = fieldNc[f];
    2043:         PetscCallMPI(MPIU_Allreduce(in, out, 2, MPIU_INT, MPI_MAX, PetscObjectComm((PetscObject)dm)));
    2044:         bs = (-out[0] == out[1]) ? out[1] : 1;
    2045:         PetscCall(ISSetBlockSize((*fields)[f], bs));
    2046:       }
    2047:     }
    2048:     PetscCall(PetscFree3(fieldSizes, fieldNc, fieldIndices));
    2049:   } else PetscTryTypeMethod(dm, createfieldis, numFields, fieldNames, fields);
    2050:   PetscFunctionReturn(PETSC_SUCCESS);
    2051: }

    2053: /*@C
    2054:   DMCreateFieldDecomposition - Returns a list of `IS` objects defining a decomposition of a problem into subproblems
    2055:   corresponding to different fields.

    2057:   Not Collective; No Fortran Support

    2059:   Input Parameter:
    2060: . dm - the `DM` object

    2062:   Output Parameters:
    2063: + len      - The number of fields (or `NULL` if not requested)
    2064: . namelist - The name for each field (or `NULL` if not requested)
    2065: . islist   - The global indices for each field (or `NULL` if not requested)
    2066: - dmlist   - The `DM`s for each field subproblem (or `NULL`, if not requested; if `NULL` is returned, no `DM`s are defined)

    2068:   Level: intermediate

    2070:   Notes:
    2071:   Each `IS` contains the global indices of the dofs of the corresponding field, defined by
    2072:   `DMAddField()`. The optional list of `DM`s define the `DM` for each subproblem.

    2074:   The same as `DMCreateFieldIS()` but also returns a `DM` for each field.

    2076:   The user is responsible for freeing all requested arrays. In particular, every entry of `namelist` should be freed with
    2077:   `PetscFree()`, every entry of `islist` should be destroyed with `ISDestroy()`, every entry of `dmlist` should be destroyed with `DMDestroy()`,
    2078:   and all of the arrays should be freed with `PetscFree()`.

    2080:   Fortran Notes:
    2081:   Use the declarations
    2082: .vb
    2083:   character(80), pointer :: namelist(:)
    2084:   IS, pointer :: islist(:)
    2085:   DM, pointer :: dmlist(:)
    2086: .ve

    2088:   `namelist` must be provided, `islist` may be `PETSC_NULL_IS_POINTER` and `dmlist` may be `PETSC_NULL_DM_POINTER`

    2090:   Use `DMDestroyFieldDecomposition()` to free the returned objects

    2092:   Developer Notes:
    2093:   It is not clear why this function and `DMCreateFieldIS()` exist. Having two seems redundant and confusing.

    2095:   Unlike  `DMRefine()`, `DMCoarsen()`, and `DMCreateDomainDecomposition()` this provides no mechanism to provide hooks that are called after the
    2096:   decomposition is computed.

    2098: .seealso: [](ch_dmbase), `DM`, `DMAddField()`, `DMCreateFieldIS()`, `DMCreateSubDM()`, `DMCreateDomainDecomposition()`, `DMDestroy()`, `DMView()`, `DMCreateInterpolation()`, `DMCreateColoring()`, `DMCreateMatrix()`, `DMCreateMassMatrix()`, `DMRefine()`, `DMCoarsen()`
    2099: @*/
    2100: PetscErrorCode DMCreateFieldDecomposition(DM dm, PetscInt *len, char ***namelist, IS *islist[], DM *dmlist[])
    2101: {
    2102:   PetscFunctionBegin;
    2104:   if (len) {
    2105:     PetscAssertPointer(len, 2);
    2106:     *len = 0;
    2107:   }
    2108:   if (namelist) {
    2109:     PetscAssertPointer(namelist, 3);
    2110:     *namelist = NULL;
    2111:   }
    2112:   if (islist) {
    2113:     PetscAssertPointer(islist, 4);
    2114:     *islist = NULL;
    2115:   }
    2116:   if (dmlist) {
    2117:     PetscAssertPointer(dmlist, 5);
    2118:     *dmlist = NULL;
    2119:   }
    2120:   /*
    2121:    Is it a good idea to apply the following check across all impls?
    2122:    Perhaps some impls can have a well-defined decomposition before DMSetUp?
    2123:    This, however, follows the general principle that accessors are not well-behaved until the object is set up.
    2124:    */
    2125:   PetscCheck(dm->setupcalled, PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_WRONGSTATE, "Decomposition defined only after DMSetUp");
    2126:   if (!dm->ops->createfielddecomposition) {
    2127:     PetscSection section;
    2128:     PetscInt     numFields, f;

    2130:     PetscCall(DMGetLocalSection(dm, &section));
    2131:     if (section) PetscCall(PetscSectionGetNumFields(section, &numFields));
    2132:     if (section && numFields && dm->ops->createsubdm) {
    2133:       if (len) *len = numFields;
    2134:       if (namelist) PetscCall(PetscMalloc1(numFields, namelist));
    2135:       if (islist) PetscCall(PetscMalloc1(numFields, islist));
    2136:       if (dmlist) PetscCall(PetscMalloc1(numFields, dmlist));
    2137:       for (f = 0; f < numFields; ++f) {
    2138:         const char *fieldName;

    2140:         PetscCall(DMCreateSubDM(dm, 1, &f, islist ? &(*islist)[f] : NULL, dmlist ? &(*dmlist)[f] : NULL));
    2141:         if (namelist) {
    2142:           PetscCall(PetscSectionGetFieldName(section, f, &fieldName));
    2143:           PetscCall(PetscStrallocpy(fieldName, &(*namelist)[f]));
    2144:         }
    2145:       }
    2146:     } else {
    2147:       PetscCall(DMCreateFieldIS(dm, len, namelist, islist));
    2148:       /* By default there are no DMs associated with subproblems. */
    2149:       if (dmlist) *dmlist = NULL;
    2150:     }
    2151:   } else PetscUseTypeMethod(dm, createfielddecomposition, len, namelist, islist, dmlist);
    2152:   PetscFunctionReturn(PETSC_SUCCESS);
    2153: }

    2155: /*@
    2156:   DMCreateSubDM - Returns an `IS` and `DM` encapsulating a subproblem defined by the fields passed in.
    2157:   The fields are defined by `DMCreateFieldIS()`.

    2159:   Not collective

    2161:   Input Parameters:
    2162: + dm        - The `DM` object
    2163: . numFields - The number of fields to select
    2164: - fields    - The field numbers of the selected fields

    2166:   Output Parameters:
    2167: + is    - The global indices for all the degrees of freedom in the new sub `DM`, use `NULL` if not needed
    2168: - subdm - The `DM` for the subproblem, use `NULL` if not needed

    2170:   Level: intermediate

    2172:   Note:
    2173:   You need to call `DMPlexSetMigrationSF()` on the original `DM` if you want the Global-To-Natural map to be automatically constructed

    2175: .seealso: [](ch_dmbase), `DM`, `DMCreateFieldIS()`, `DMCreateFieldDecomposition()`, `DMAddField()`, `DMCreateSuperDM()`, `IS`, `VecISCopy()`, `DMPlexSetMigrationSF()`, `DMDestroy()`, `DMView()`, `DMCreateInterpolation()`, `DMCreateColoring()`, `DMCreateMatrix()`, `DMCreateMassMatrix()`
    2176: @*/
    2177: PetscErrorCode DMCreateSubDM(DM dm, PetscInt numFields, const PetscInt fields[], IS *is, DM *subdm)
    2178: {
    2179:   PetscFunctionBegin;
    2181:   PetscAssertPointer(fields, 3);
    2182:   if (is) PetscAssertPointer(is, 4);
    2183:   if (subdm) PetscAssertPointer(subdm, 5);
    2184:   PetscUseTypeMethod(dm, createsubdm, numFields, fields, is, subdm);
    2185:   PetscFunctionReturn(PETSC_SUCCESS);
    2186: }

    2188: /*@C
    2189:   DMCreateSuperDM - Returns an arrays of `IS` and a single `DM` encapsulating a superproblem defined by multiple `DM`s passed in.

    2191:   Not collective

    2193:   Input Parameters:
    2194: + dms - The `DM` objects
    2195: - n   - The number of `DM`s

    2197:   Output Parameters:
    2198: + is      - The global indices for each of subproblem within the super `DM`, or `NULL`, its length is `n`
    2199: - superdm - The `DM` for the superproblem

    2201:   Level: intermediate

    2203:   Note:
    2204:   You need to call `DMPlexSetMigrationSF()` on the original `DM` if you want the Global-To-Natural map to be automatically constructed

    2206: .seealso: [](ch_dmbase), `DM`, `DMCreateSubDM()`, `DMPlexSetMigrationSF()`, `DMDestroy()`, `DMView()`, `DMCreateInterpolation()`, `DMCreateColoring()`, `DMCreateMatrix()`, `DMCreateMassMatrix()`, `DMCreateFieldIS()`, `DMCreateDomainDecomposition()`
    2207: @*/
    2208: PetscErrorCode DMCreateSuperDM(DM dms[], PetscInt n, IS *is[], DM *superdm)
    2209: {
    2210:   PetscInt i;

    2212:   PetscFunctionBegin;
    2213:   PetscAssertPointer(dms, 1);
    2215:   if (is) PetscAssertPointer(is, 3);
    2216:   PetscAssertPointer(superdm, 4);
    2217:   PetscCheck(n >= 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Number of DMs must be nonnegative: %" PetscInt_FMT, n);
    2218:   if (n) {
    2219:     DM dm = dms[0];
    2220:     PetscCheck(dm->ops->createsuperdm, PetscObjectComm((PetscObject)dm), PETSC_ERR_SUP, "No method createsuperdm for DM of type %s", ((PetscObject)dm)->type_name);
    2221:     PetscCall((*dm->ops->createsuperdm)(dms, n, is, superdm));
    2222:   }
    2223:   PetscFunctionReturn(PETSC_SUCCESS);
    2224: }

    2226: /*@C
    2227:   DMCreateDomainDecomposition - Returns lists of `IS` objects defining a decomposition of a
    2228:   problem into subproblems corresponding to restrictions to pairs of nested subdomains.

    2230:   Not Collective

    2232:   Input Parameter:
    2233: . dm - the `DM` object

    2235:   Output Parameters:
    2236: + n           - The number of subproblems in the domain decomposition (or `NULL` if not requested), also the length of the four arrays below
    2237: . namelist    - The name for each subdomain (or `NULL` if not requested)
    2238: . innerislist - The global indices for each inner subdomain (or `NULL`, if not requested)
    2239: . outerislist - The global indices for each outer subdomain (or `NULL`, if not requested)
    2240: - dmlist      - The `DM`s for each subdomain subproblem (or `NULL`, if not requested; if `NULL` is returned, no `DM`s are defined)

    2242:   Level: intermediate

    2244:   Notes:
    2245:   Each `IS` contains the global indices of the dofs of the corresponding subdomains with in the
    2246:   dofs of the original `DM`. The inner subdomains conceptually define a nonoverlapping
    2247:   covering, while outer subdomains can overlap.

    2249:   The optional list of `DM`s define a `DM` for each subproblem.

    2251:   The user is responsible for freeing all requested arrays. In particular, every entry of `namelist` should be freed with
    2252:   `PetscFree()`, every entry of `innerislist` and `outerislist` should be destroyed with `ISDestroy()`, every entry of `dmlist` should be destroyed with `DMDestroy()`,
    2253:   and all of the arrays should be freed with `PetscFree()`.

    2255:   Developer Notes:
    2256:   The `dmlist` is for the inner subdomains or the outer subdomains or all subdomains?

    2258:   The names are inconsistent, the hooks use `DMSubDomainHook` which is nothing like `DMCreateDomainDecomposition()` while `DMRefineHook` is used for `DMRefine()`.

    2260: .seealso: [](ch_dmbase), `DM`, `DMCreateFieldDecomposition()`, `DMDestroy()`, `DMCreateDomainDecompositionScatters()`, `DMView()`, `DMCreateInterpolation()`,
    2261:           `DMSubDomainHookAdd()`, `DMSubDomainHookRemove()`, `DMCreateColoring()`, `DMCreateMatrix()`, `DMCreateMassMatrix()`, `DMRefine()`, `DMCoarsen()`
    2262: @*/
    2263: PetscErrorCode DMCreateDomainDecomposition(DM dm, PetscInt *n, char **namelist[], IS *innerislist[], IS *outerislist[], DM *dmlist[])
    2264: {
    2265:   DMSubDomainHookLink link;
    2266:   PetscInt            i, l;

    2268:   PetscFunctionBegin;
    2270:   if (n) {
    2271:     PetscAssertPointer(n, 2);
    2272:     *n = 0;
    2273:   }
    2274:   if (namelist) {
    2275:     PetscAssertPointer(namelist, 3);
    2276:     *namelist = NULL;
    2277:   }
    2278:   if (innerislist) {
    2279:     PetscAssertPointer(innerislist, 4);
    2280:     *innerislist = NULL;
    2281:   }
    2282:   if (outerislist) {
    2283:     PetscAssertPointer(outerislist, 5);
    2284:     *outerislist = NULL;
    2285:   }
    2286:   if (dmlist) {
    2287:     PetscAssertPointer(dmlist, 6);
    2288:     *dmlist = NULL;
    2289:   }
    2290:   /*
    2291:    Is it a good idea to apply the following check across all impls?
    2292:    Perhaps some impls can have a well-defined decomposition before DMSetUp?
    2293:    This, however, follows the general principle that accessors are not well-behaved until the object is set up.
    2294:    */
    2295:   PetscCheck(dm->setupcalled, PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_WRONGSTATE, "Decomposition defined only after DMSetUp");
    2296:   if (dm->ops->createdomaindecomposition) {
    2297:     PetscUseTypeMethod(dm, createdomaindecomposition, &l, namelist, innerislist, outerislist, dmlist);
    2298:     /* copy subdomain hooks and context over to the subdomain DMs */
    2299:     if (dmlist && *dmlist) {
    2300:       for (i = 0; i < l; i++) {
    2301:         for (link = dm->subdomainhook; link; link = link->next) {
    2302:           if (link->ddhook) PetscCall((*link->ddhook)(dm, (*dmlist)[i], link->ctx));
    2303:         }
    2304:         if (dm->ctx) (*dmlist)[i]->ctx = dm->ctx;
    2305:       }
    2306:     }
    2307:     if (n) *n = l;
    2308:   }
    2309:   PetscFunctionReturn(PETSC_SUCCESS);
    2310: }

    2312: /*@C
    2313:   DMCreateDomainDecompositionScatters - Returns scatters to the subdomain vectors from the global vector for subdomains created with
    2314:   `DMCreateDomainDecomposition()`

    2316:   Not Collective

    2318:   Input Parameters:
    2319: + dm     - the `DM` object
    2320: . n      - the number of subdomains
    2321: - subdms - the local subdomains

    2323:   Output Parameters:
    2324: + iscat - scatter from global vector to nonoverlapping global vector entries on subdomain
    2325: . oscat - scatter from global vector to overlapping global vector entries on subdomain
    2326: - gscat - scatter from global vector to local vector on subdomain (fills in ghosts)

    2328:   Level: developer

    2330:   Note:
    2331:   This is an alternative to the `iis` and `ois` arguments in `DMCreateDomainDecomposition()` that allow for the solution
    2332:   of general nonlinear problems with overlapping subdomain methods.  While merely having index sets that enable subsets
    2333:   of the residual equations to be created is fine for linear problems, nonlinear problems require local assembly of
    2334:   solution and residual data.

    2336:   Developer Note:
    2337:   Can the `subdms` input be anything or are they exactly the `DM` obtained from
    2338:   `DMCreateDomainDecomposition()`?

    2340: .seealso: [](ch_dmbase), `DM`, `DMCreateDomainDecomposition()`, `DMDestroy()`, `DMView()`, `DMCreateInterpolation()`, `DMCreateColoring()`, `DMCreateMatrix()`, `DMCreateMassMatrix()`, `DMCreateFieldIS()`
    2341: @*/
    2342: PetscErrorCode DMCreateDomainDecompositionScatters(DM dm, PetscInt n, DM subdms[], VecScatter *iscat[], VecScatter *oscat[], VecScatter *gscat[])
    2343: {
    2344:   PetscFunctionBegin;
    2346:   PetscAssertPointer(subdms, 3);
    2347:   PetscUseTypeMethod(dm, createddscatters, n, subdms, iscat, oscat, gscat);
    2348:   PetscFunctionReturn(PETSC_SUCCESS);
    2349: }

    2351: /*@
    2352:   DMRefine - Refines a `DM` object using a standard nonadaptive refinement of the underlying mesh

    2354:   Collective

    2356:   Input Parameters:
    2357: + dm   - the `DM` object
    2358: - comm - the communicator to contain the new `DM` object (or `MPI_COMM_NULL`)

    2360:   Output Parameter:
    2361: . dmf - the refined `DM`, or `NULL`

    2363:   Options Database Key:
    2364: . -dm_plex_cell_refiner strategy - chooses the refinement strategy, e.g. regular, tohex

    2366:   Level: developer

    2368:   Note:
    2369:   If no refinement was done, the return value is `NULL`

    2371: .seealso: [](ch_dmbase), `DM`, `DMCoarsen()`, `DMDestroy()`, `DMView()`, `DMCreateGlobalVector()`, `DMCreateInterpolation()`, `DMCreateDomainDecomposition()`,
    2372:           `DMRefineHookAdd()`, `DMRefineHookRemove()`
    2373: @*/
    2374: PetscErrorCode DMRefine(DM dm, MPI_Comm comm, DM *dmf)
    2375: {
    2376:   DMRefineHookLink link;

    2378:   PetscFunctionBegin;
    2380:   PetscCall(PetscLogEventBegin(DM_Refine, dm, 0, 0, 0));
    2381:   PetscUseTypeMethod(dm, refine, comm, dmf);
    2382:   if (*dmf) {
    2383:     (*dmf)->ops->creatematrix = dm->ops->creatematrix;

    2385:     PetscCall(PetscObjectCopyFortranFunctionPointers((PetscObject)dm, (PetscObject)*dmf));

    2387:     (*dmf)->ctx       = dm->ctx;
    2388:     (*dmf)->leveldown = dm->leveldown;
    2389:     (*dmf)->levelup   = dm->levelup + 1;

    2391:     PetscCall(DMSetMatType(*dmf, dm->mattype));
    2392:     for (link = dm->refinehook; link; link = link->next) {
    2393:       if (link->refinehook) PetscCall((*link->refinehook)(dm, *dmf, link->ctx));
    2394:     }
    2395:   }
    2396:   PetscCall(PetscLogEventEnd(DM_Refine, dm, 0, 0, 0));
    2397:   PetscFunctionReturn(PETSC_SUCCESS);
    2398: }

    2400: /*@C
    2401:   DMRefineHookAdd - adds a callback to be run when interpolating a nonlinear problem to a finer grid

    2403:   Logically Collective; No Fortran Support

    2405:   Input Parameters:
    2406: + coarse     - `DM` on which to run a hook when interpolating to a finer level
    2407: . refinehook - function to run when setting up the finer level
    2408: . interphook - function to run to update data on finer levels (once per `SNESSolve()`)
    2409: - ctx        - [optional] context for provide data for the hooks (may be `NULL`)

    2411:   Calling sequence of `refinehook`:
    2412: + coarse - coarse level `DM`
    2413: . fine   - fine level `DM` to interpolate problem to
    2414: - ctx    - optional function context

    2416:   Calling sequence of `interphook`:
    2417: + coarse - coarse level `DM`
    2418: . interp - matrix interpolating a coarse-level solution to the finer grid
    2419: . fine   - fine level `DM` to update
    2420: - ctx    - optional function context

    2422:   Level: advanced

    2424:   Notes:
    2425:   This function is only needed if auxiliary data that is attached to the `DM`s via, for example, `PetscObjectCompose()`, needs to be
    2426:   passed to fine grids while grid sequencing.

    2428:   The actual interpolation is done when `DMInterpolate()` is called.

    2430:   If this function is called multiple times, the hooks will be run in the order they are added.

    2432: .seealso: [](ch_dmbase), `DM`, `DMCoarsenHookAdd()`, `DMInterpolate()`, `SNESFASGetInterpolation()`, `SNESFASGetInjection()`, `PetscObjectCompose()`, `PetscContainerCreate()`
    2433: @*/
    2434: PetscErrorCode DMRefineHookAdd(DM coarse, PetscErrorCode (*refinehook)(DM coarse, DM fine, PetscCtx ctx), PetscErrorCode (*interphook)(DM coarse, Mat interp, DM fine, PetscCtx ctx), PetscCtx ctx)
    2435: {
    2436:   DMRefineHookLink link, *p;

    2438:   PetscFunctionBegin;
    2440:   for (p = &coarse->refinehook; *p; p = &(*p)->next) { /* Scan to the end of the current list of hooks */
    2441:     if ((*p)->refinehook == refinehook && (*p)->interphook == interphook && (*p)->ctx == ctx) PetscFunctionReturn(PETSC_SUCCESS);
    2442:   }
    2443:   PetscCall(PetscNew(&link));
    2444:   link->refinehook = refinehook;
    2445:   link->interphook = interphook;
    2446:   link->ctx        = ctx;
    2447:   link->next       = NULL;
    2448:   *p               = link;
    2449:   PetscFunctionReturn(PETSC_SUCCESS);
    2450: }

    2452: /*@C
    2453:   DMRefineHookRemove - remove a callback from the list of hooks, that have been set with `DMRefineHookAdd()`, to be run when interpolating
    2454:   a nonlinear problem to a finer grid

    2456:   Logically Collective; No Fortran Support

    2458:   Input Parameters:
    2459: + coarse     - the `DM` on which to run a hook when restricting to a coarser level
    2460: . refinehook - function to run when setting up a finer level
    2461: . interphook - function to run to update data on finer levels
    2462: - ctx        - [optional] application context for provide data for the hooks (may be `NULL`)

    2464:   Calling sequence of refinehook:
    2465: + coarse - the coarse `DM`
    2466: . fine   - the fine `DM`
    2467: - ctx    - context for the function

    2469:   Calling sequence of interphook:
    2470: + coarse - the coarse `DM`
    2471: . interp - the interpolation `Mat` from coarse to fine
    2472: . fine   - the fine `DM`
    2473: - ctx    - context for the function

    2475:   Level: advanced

    2477:   Note:
    2478:   This function does nothing if the hook is not in the list.

    2480: .seealso: [](ch_dmbase), `DM`, `DMRefineHookAdd()`, `DMCoarsenHookRemove()`, `DMInterpolate()`, `SNESFASGetInterpolation()`, `SNESFASGetInjection()`, `PetscObjectCompose()`, `PetscContainerCreate()`
    2481: @*/
    2482: PetscErrorCode DMRefineHookRemove(DM coarse, PetscErrorCode (*refinehook)(DM coarse, DM fine, PetscCtx ctx), PetscErrorCode (*interphook)(DM coarse, Mat interp, DM fine, PetscCtx ctx), PetscCtx ctx)
    2483: {
    2484:   DMRefineHookLink link, *p;

    2486:   PetscFunctionBegin;
    2488:   for (p = &coarse->refinehook; *p; p = &(*p)->next) { /* Search the list of current hooks */
    2489:     if ((*p)->refinehook == refinehook && (*p)->interphook == interphook && (*p)->ctx == ctx) {
    2490:       link = *p;
    2491:       *p   = link->next;
    2492:       PetscCall(PetscFree(link));
    2493:       break;
    2494:     }
    2495:   }
    2496:   PetscFunctionReturn(PETSC_SUCCESS);
    2497: }

    2499: /*@
    2500:   DMInterpolate - interpolates user-defined problem data attached to a `DM` to a finer `DM` by running hooks registered by `DMRefineHookAdd()`

    2502:   Collective if any hooks are

    2504:   Input Parameters:
    2505: + coarse - coarser `DM` to use as a base
    2506: . interp - interpolation matrix, apply using `MatInterpolate()`
    2507: - fine   - finer `DM` to update

    2509:   Level: developer

    2511:   Developer Note:
    2512:   This routine is called `DMInterpolate()` while the hook is called `DMRefineHookAdd()`. It would be better to have an
    2513:   an API with consistent terminology.

    2515: .seealso: [](ch_dmbase), `DM`, `DMRefineHookAdd()`, `MatInterpolate()`
    2516: @*/
    2517: PetscErrorCode DMInterpolate(DM coarse, Mat interp, DM fine)
    2518: {
    2519:   DMRefineHookLink link;

    2521:   PetscFunctionBegin;
    2522:   for (link = fine->refinehook; link; link = link->next) {
    2523:     if (link->interphook) PetscCall((*link->interphook)(coarse, interp, fine, link->ctx));
    2524:   }
    2525:   PetscFunctionReturn(PETSC_SUCCESS);
    2526: }

    2528: /*@
    2529:   DMInterpolateSolution - Interpolates a solution from a coarse mesh to a fine mesh.

    2531:   Collective

    2533:   Input Parameters:
    2534: + coarse    - coarse `DM`
    2535: . fine      - fine `DM`
    2536: . interp    - (optional) the matrix computed by `DMCreateInterpolation()`.  Implementations may not need this, but if it
    2537:             is available it can avoid some recomputation.  If it is provided, `MatInterpolate()` will be used if
    2538:             the coarse `DM` does not have a specialized implementation.
    2539: - coarseSol - solution on the coarse mesh

    2541:   Output Parameter:
    2542: . fineSol - the interpolation of coarseSol to the fine mesh

    2544:   Level: developer

    2546:   Note:
    2547:   This function exists because the interpolation of a solution vector between meshes is not always a linear
    2548:   map.  For example, if a boundary value problem has an inhomogeneous Dirichlet boundary condition that is compressed
    2549:   out of the solution vector.  Or if interpolation is inherently a nonlinear operation, such as a method using
    2550:   slope-limiting reconstruction.

    2552:   Developer Note:
    2553:   This doesn't just interpolate "solutions" so its API name is questionable.

    2555: .seealso: [](ch_dmbase), `DM`, `DMInterpolate()`, `DMCreateInterpolation()`
    2556: @*/
    2557: PetscErrorCode DMInterpolateSolution(DM coarse, DM fine, Mat interp, Vec coarseSol, Vec fineSol)
    2558: {
    2559:   PetscErrorCode (*interpsol)(DM, DM, Mat, Vec, Vec) = NULL;

    2561:   PetscFunctionBegin;

    2567:   PetscCall(PetscObjectQueryFunction((PetscObject)coarse, "DMInterpolateSolution_C", &interpsol));
    2568:   if (interpsol) {
    2569:     PetscCall((*interpsol)(coarse, fine, interp, coarseSol, fineSol));
    2570:   } else if (interp) {
    2571:     PetscCall(MatInterpolate(interp, coarseSol, fineSol));
    2572:   } else SETERRQ(PetscObjectComm((PetscObject)coarse), PETSC_ERR_SUP, "DM %s does not implement DMInterpolateSolution()", ((PetscObject)coarse)->type_name);
    2573:   PetscFunctionReturn(PETSC_SUCCESS);
    2574: }

    2576: /*@
    2577:   DMGetRefineLevel - Gets the number of refinements that have generated this `DM` from some initial `DM`.

    2579:   Not Collective

    2581:   Input Parameter:
    2582: . dm - the `DM` object

    2584:   Output Parameter:
    2585: . level - number of refinements

    2587:   Level: developer

    2589:   Note:
    2590:   This can be used, by example, to set the number of coarser levels associated with this `DM` for a multigrid solver.

    2592: .seealso: [](ch_dmbase), `DM`, `DMRefine()`, `DMCoarsen()`, `DMGetCoarsenLevel()`, `DMDestroy()`, `DMView()`, `DMCreateGlobalVector()`, `DMCreateInterpolation()`
    2593: @*/
    2594: PetscErrorCode DMGetRefineLevel(DM dm, PetscInt *level)
    2595: {
    2596:   PetscFunctionBegin;
    2598:   *level = dm->levelup;
    2599:   PetscFunctionReturn(PETSC_SUCCESS);
    2600: }

    2602: /*@
    2603:   DMSetRefineLevel - Sets the number of refinements that have generated this `DM`.

    2605:   Not Collective

    2607:   Input Parameters:
    2608: + dm    - the `DM` object
    2609: - level - number of refinements

    2611:   Level: advanced

    2613:   Notes:
    2614:   This value is used by `PCMG` to determine how many multigrid levels to use

    2616:   The values are usually set automatically by the process that is causing the refinements of an initial `DM` by calling this routine.

    2618: .seealso: [](ch_dmbase), `DM`, `DMGetRefineLevel()`, `DMCoarsen()`, `DMGetCoarsenLevel()`, `DMDestroy()`, `DMView()`, `DMCreateGlobalVector()`, `DMCreateInterpolation()`
    2619: @*/
    2620: PetscErrorCode DMSetRefineLevel(DM dm, PetscInt level)
    2621: {
    2622:   PetscFunctionBegin;
    2624:   dm->levelup = level;
    2625:   PetscFunctionReturn(PETSC_SUCCESS);
    2626: }

    2628: /*@
    2629:   DMExtrude - Extrude a `DM` object from a surface

    2631:   Collective

    2633:   Input Parameters:
    2634: + dm     - the `DM` object
    2635: - layers - the number of extruded cell layers

    2637:   Output Parameter:
    2638: . dme - the extruded `DM`, or `NULL`

    2640:   Level: developer

    2642:   Note:
    2643:   If no extrusion was done, the return value is `NULL`

    2645: .seealso: [](ch_dmbase), `DM`, `DMRefine()`, `DMCoarsen()`, `DMDestroy()`, `DMView()`, `DMCreateGlobalVector()`
    2646: @*/
    2647: PetscErrorCode DMExtrude(DM dm, PetscInt layers, DM *dme)
    2648: {
    2649:   PetscFunctionBegin;
    2651:   PetscUseTypeMethod(dm, extrude, layers, dme);
    2652:   if (*dme) {
    2653:     (*dme)->ops->creatematrix = dm->ops->creatematrix;
    2654:     PetscCall(PetscObjectCopyFortranFunctionPointers((PetscObject)dm, (PetscObject)*dme));
    2655:     (*dme)->ctx = dm->ctx;
    2656:     PetscCall(DMSetMatType(*dme, dm->mattype));
    2657:   }
    2658:   PetscFunctionReturn(PETSC_SUCCESS);
    2659: }

    2661: PetscErrorCode DMGetBasisTransformDM_Internal(DM dm, DM *tdm)
    2662: {
    2663:   PetscFunctionBegin;
    2665:   PetscAssertPointer(tdm, 2);
    2666:   *tdm = dm->transformDM;
    2667:   PetscFunctionReturn(PETSC_SUCCESS);
    2668: }

    2670: PetscErrorCode DMGetBasisTransformVec_Internal(DM dm, Vec *tv)
    2671: {
    2672:   PetscFunctionBegin;
    2674:   PetscAssertPointer(tv, 2);
    2675:   *tv = dm->transform;
    2676:   PetscFunctionReturn(PETSC_SUCCESS);
    2677: }

    2679: /*@
    2680:   DMHasBasisTransform - Whether the `DM` employs a basis transformation from functions in global vectors to functions in local vectors

    2682:   Input Parameter:
    2683: . dm - The `DM`

    2685:   Output Parameter:
    2686: . flg - `PETSC_TRUE` if a basis transformation should be done

    2688:   Level: developer

    2690: .seealso: [](ch_dmbase), `DM`, `DMPlexGlobalToLocalBasis()`, `DMPlexLocalToGlobalBasis()`, `DMPlexCreateBasisRotation()`
    2691: @*/
    2692: PetscErrorCode DMHasBasisTransform(DM dm, PetscBool *flg)
    2693: {
    2694:   Vec tv;

    2696:   PetscFunctionBegin;
    2698:   PetscAssertPointer(flg, 2);
    2699:   PetscCall(DMGetBasisTransformVec_Internal(dm, &tv));
    2700:   *flg = tv ? PETSC_TRUE : PETSC_FALSE;
    2701:   PetscFunctionReturn(PETSC_SUCCESS);
    2702: }

    2704: PetscErrorCode DMConstructBasisTransform_Internal(DM dm)
    2705: {
    2706:   PetscSection s, ts;
    2707:   PetscScalar *ta;
    2708:   PetscInt     cdim, pStart, pEnd, p, Nf, f, Nc, dof;

    2710:   PetscFunctionBegin;
    2711:   PetscCall(DMGetCoordinateDim(dm, &cdim));
    2712:   PetscCall(DMGetLocalSection(dm, &s));
    2713:   PetscCall(PetscSectionGetChart(s, &pStart, &pEnd));
    2714:   PetscCall(PetscSectionGetNumFields(s, &Nf));
    2715:   PetscCall(DMClone(dm, &dm->transformDM));
    2716:   PetscCall(DMGetLocalSection(dm->transformDM, &ts));
    2717:   PetscCall(PetscSectionSetNumFields(ts, Nf));
    2718:   PetscCall(PetscSectionSetChart(ts, pStart, pEnd));
    2719:   for (f = 0; f < Nf; ++f) {
    2720:     PetscCall(PetscSectionGetFieldComponents(s, f, &Nc));
    2721:     /* We could start to label fields by their transformation properties */
    2722:     if (Nc != cdim) continue;
    2723:     for (p = pStart; p < pEnd; ++p) {
    2724:       PetscCall(PetscSectionGetFieldDof(s, p, f, &dof));
    2725:       if (!dof) continue;
    2726:       PetscCall(PetscSectionSetFieldDof(ts, p, f, PetscSqr(cdim)));
    2727:       PetscCall(PetscSectionAddDof(ts, p, PetscSqr(cdim)));
    2728:     }
    2729:   }
    2730:   PetscCall(PetscSectionSetUp(ts));
    2731:   PetscCall(DMCreateLocalVector(dm->transformDM, &dm->transform));
    2732:   PetscCall(VecGetArray(dm->transform, &ta));
    2733:   for (p = pStart; p < pEnd; ++p) {
    2734:     for (f = 0; f < Nf; ++f) {
    2735:       PetscCall(PetscSectionGetFieldDof(ts, p, f, &dof));
    2736:       if (dof) {
    2737:         PetscReal          x[3] = {0.0, 0.0, 0.0};
    2738:         PetscScalar       *tva;
    2739:         const PetscScalar *A;

    2741:         /* TODO Get quadrature point for this dual basis vector for coordinate */
    2742:         PetscCall((*dm->transformGetMatrix)(dm, x, PETSC_TRUE, &A, dm->transformCtx));
    2743:         PetscCall(DMPlexPointLocalFieldRef(dm->transformDM, p, f, ta, (void *)&tva));
    2744:         PetscCall(PetscArraycpy(tva, A, PetscSqr(cdim)));
    2745:       }
    2746:     }
    2747:   }
    2748:   PetscCall(VecRestoreArray(dm->transform, &ta));
    2749:   PetscFunctionReturn(PETSC_SUCCESS);
    2750: }

    2752: /*@
    2753:   DMCopyTransform - Copy the basis transform context and callbacks from `dm` to `newdm`

    2755:   Not Collective

    2757:   Input Parameter:
    2758: . dm - the source `DM`

    2760:   Output Parameter:
    2761: . newdm - the destination `DM`

    2763:   Level: developer

    2765:   Note:
    2766:   If the transform requires setup, `DMConstructBasisTransform_Internal()` is invoked on `newdm`.

    2768: .seealso: [](ch_dmbase), `DM`, `DMCopyDS()`, `DMCopyDisc()`
    2769: @*/
    2770: PetscErrorCode DMCopyTransform(DM dm, DM newdm)
    2771: {
    2772:   PetscFunctionBegin;
    2775:   newdm->transformCtx       = dm->transformCtx;
    2776:   newdm->transformSetUp     = dm->transformSetUp;
    2777:   newdm->transformDestroy   = NULL;
    2778:   newdm->transformGetMatrix = dm->transformGetMatrix;
    2779:   if (newdm->transformSetUp) PetscCall(DMConstructBasisTransform_Internal(newdm));
    2780:   PetscFunctionReturn(PETSC_SUCCESS);
    2781: }

    2783: /*@C
    2784:   DMGlobalToLocalHookAdd - adds a callback to be run when `DMGlobalToLocal()` is called

    2786:   Logically Collective

    2788:   Input Parameters:
    2789: + dm        - the `DM`
    2790: . beginhook - function to run at the beginning of `DMGlobalToLocalBegin()`
    2791: . endhook   - function to run after `DMGlobalToLocalEnd()` has completed
    2792: - ctx       - [optional] context for provide data for the hooks (may be `NULL`)

    2794:   Calling sequence of `beginhook`:
    2795: + dm   - global `DM`
    2796: . g    - global vector
    2797: . mode - mode
    2798: . l    - local vector
    2799: - ctx  - optional function context

    2801:   Calling sequence of `endhook`:
    2802: + dm   - global `DM`
    2803: . g    - global vector
    2804: . mode - mode
    2805: . l    - local vector
    2806: - ctx  - optional function context

    2808:   Level: advanced

    2810:   Note:
    2811:   The hook may be used to provide, for example, values that represent boundary conditions in the local vectors that do not exist on the global vector.

    2813: .seealso: [](ch_dmbase), `DM`, `DMGlobalToLocal()`, `DMRefineHookAdd()`, `SNESFASGetInterpolation()`, `SNESFASGetInjection()`, `PetscObjectCompose()`, `PetscContainerCreate()`
    2814: @*/
    2815: PetscErrorCode DMGlobalToLocalHookAdd(DM dm, PetscErrorCode (*beginhook)(DM dm, Vec g, InsertMode mode, Vec l, PetscCtx ctx), PetscErrorCode (*endhook)(DM dm, Vec g, InsertMode mode, Vec l, PetscCtx ctx), PetscCtx ctx)
    2816: {
    2817:   DMGlobalToLocalHookLink link, *p;

    2819:   PetscFunctionBegin;
    2821:   for (p = &dm->gtolhook; *p; p = &(*p)->next) { } /* Scan to the end of the current list of hooks */
    2822:   PetscCall(PetscNew(&link));
    2823:   link->beginhook = beginhook;
    2824:   link->endhook   = endhook;
    2825:   link->ctx       = ctx;
    2826:   link->next      = NULL;
    2827:   *p              = link;
    2828:   PetscFunctionReturn(PETSC_SUCCESS);
    2829: }

    2831: static PetscErrorCode DMGlobalToLocalHook_Constraints(DM dm, Vec g, InsertMode mode, Vec l, PetscCtx ctx)
    2832: {
    2833:   Mat          cMat;
    2834:   Vec          cVec, cBias;
    2835:   PetscSection section, cSec;
    2836:   PetscInt     pStart, pEnd, p, dof;

    2838:   PetscFunctionBegin;
    2839:   (void)g;
    2840:   (void)ctx;
    2842:   PetscCall(DMGetDefaultConstraints(dm, &cSec, &cMat, &cBias));
    2843:   if (cMat && (mode == INSERT_VALUES || mode == INSERT_ALL_VALUES || mode == INSERT_BC_VALUES)) {
    2844:     PetscInt nRows;

    2846:     PetscCall(MatGetSize(cMat, &nRows, NULL));
    2847:     if (nRows <= 0) PetscFunctionReturn(PETSC_SUCCESS);
    2848:     PetscCall(DMGetLocalSection(dm, &section));
    2849:     PetscCall(MatCreateVecs(cMat, NULL, &cVec));
    2850:     PetscCall(MatMult(cMat, l, cVec));
    2851:     if (cBias) PetscCall(VecAXPY(cVec, 1., cBias));
    2852:     PetscCall(PetscSectionGetChart(cSec, &pStart, &pEnd));
    2853:     for (p = pStart; p < pEnd; p++) {
    2854:       PetscCall(PetscSectionGetDof(cSec, p, &dof));
    2855:       if (dof) {
    2856:         PetscScalar *vals;
    2857:         PetscCall(VecGetValuesSection(cVec, cSec, p, &vals));
    2858:         PetscCall(VecSetValuesSection(l, section, p, vals, INSERT_ALL_VALUES));
    2859:       }
    2860:     }
    2861:     PetscCall(VecDestroy(&cVec));
    2862:   }
    2863:   PetscFunctionReturn(PETSC_SUCCESS);
    2864: }

    2866: /*@
    2867:   DMGlobalToLocal - update local vectors from global vector

    2869:   Neighbor-wise Collective

    2871:   Input Parameters:
    2872: + dm   - the `DM` object
    2873: . g    - the global vector
    2874: . mode - `INSERT_VALUES` or `ADD_VALUES`
    2875: - l    - the local vector

    2877:   Level: beginner

    2879:   Notes:
    2880:   The communication involved in this update can be overlapped with computation by instead using
    2881:   `DMGlobalToLocalBegin()` and `DMGlobalToLocalEnd()`.

    2883:   `DMGlobalToLocalHookAdd()` may be used to provide additional operations that are performed during the update process.

    2885: .seealso: [](ch_dmbase), `DM`, `DMGlobalToLocalHookAdd()`, `DMCoarsen()`, `DMDestroy()`, `DMView()`, `DMCreateGlobalVector()`, `DMCreateInterpolation()`,
    2886:           `DMLocalToGlobalBegin()`, `DMLocalToGlobal()`, `DMLocalToGlobalEnd()`,
    2887:           `DMGlobalToLocalBegin()`, `DMGlobalToLocalEnd()`
    2888: @*/
    2889: PetscErrorCode DMGlobalToLocal(DM dm, Vec g, InsertMode mode, Vec l)
    2890: {
    2891:   PetscFunctionBegin;
    2892:   PetscCall(DMGlobalToLocalBegin(dm, g, mode, l));
    2893:   PetscCall(DMGlobalToLocalEnd(dm, g, mode, l));
    2894:   PetscFunctionReturn(PETSC_SUCCESS);
    2895: }

    2897: /*@
    2898:   DMGlobalToLocalBegin - Begins updating local vectors from global vector

    2900:   Neighbor-wise Collective

    2902:   Input Parameters:
    2903: + dm   - the `DM` object
    2904: . g    - the global vector
    2905: . mode - `INSERT_VALUES` or `ADD_VALUES`
    2906: - l    - the local vector

    2908:   Level: intermediate

    2910:   Notes:
    2911:   The operation is completed with `DMGlobalToLocalEnd()`

    2913:   One can perform local computations between the `DMGlobalToLocalBegin()` and  `DMGlobalToLocalEnd()` to overlap communication and computation

    2915:   `DMGlobalToLocal()` is a short form of  `DMGlobalToLocalBegin()` and  `DMGlobalToLocalEnd()`

    2917:   `DMGlobalToLocalHookAdd()` may be used to provide additional operations that are performed during the update process.

    2919: .seealso: [](ch_dmbase), `DM`, `DMCoarsen()`, `DMDestroy()`, `DMView()`, `DMCreateGlobalVector()`, `DMCreateInterpolation()`, `DMGlobalToLocal()`, `DMGlobalToLocalEnd()`, `DMLocalToGlobalBegin()`, `DMLocalToGlobal()`, `DMLocalToGlobalEnd()`
    2920: @*/
    2921: PetscErrorCode DMGlobalToLocalBegin(DM dm, Vec g, InsertMode mode, Vec l)
    2922: {
    2923:   PetscSF                 sf;
    2924:   DMGlobalToLocalHookLink link;

    2926:   PetscFunctionBegin;
    2928:   for (link = dm->gtolhook; link; link = link->next) {
    2929:     if (link->beginhook) PetscCall((*link->beginhook)(dm, g, mode, l, link->ctx));
    2930:   }
    2931:   PetscCall(DMGetSectionSF(dm, &sf));
    2932:   if (sf) {
    2933:     const PetscScalar *gArray;
    2934:     PetscScalar       *lArray;
    2935:     PetscMemType       lmtype, gmtype;

    2937:     PetscCheck(mode != ADD_VALUES, PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_OUTOFRANGE, "Invalid insertion mode %d", (int)mode);
    2938:     PetscCall(VecGetArrayAndMemType(l, &lArray, &lmtype));
    2939:     PetscCall(VecGetArrayReadAndMemType(g, &gArray, &gmtype));
    2940:     PetscCall(PetscSFBcastWithMemTypeBegin(sf, MPIU_SCALAR, gmtype, gArray, lmtype, lArray, MPI_REPLACE));
    2941:     PetscCall(VecRestoreArrayAndMemType(l, &lArray));
    2942:     PetscCall(VecRestoreArrayReadAndMemType(g, &gArray));
    2943:   } else {
    2944:     PetscUseTypeMethod(dm, globaltolocalbegin, g, mode == INSERT_ALL_VALUES ? INSERT_VALUES : (mode == ADD_ALL_VALUES ? ADD_VALUES : mode), l);
    2945:   }
    2946:   PetscFunctionReturn(PETSC_SUCCESS);
    2947: }

    2949: /*@
    2950:   DMGlobalToLocalEnd - Ends updating local vectors from global vector

    2952:   Neighbor-wise Collective

    2954:   Input Parameters:
    2955: + dm   - the `DM` object
    2956: . g    - the global vector
    2957: . mode - `INSERT_VALUES` or `ADD_VALUES`
    2958: - l    - the local vector

    2960:   Level: intermediate

    2962:   Note:
    2963:   See `DMGlobalToLocalBegin()` for details.

    2965: .seealso: [](ch_dmbase), `DM`, `DMCoarsen()`, `DMDestroy()`, `DMView()`, `DMCreateGlobalVector()`, `DMCreateInterpolation()`, `DMGlobalToLocal()`, `DMLocalToGlobalBegin()`, `DMLocalToGlobal()`, `DMLocalToGlobalEnd()`
    2966: @*/
    2967: PetscErrorCode DMGlobalToLocalEnd(DM dm, Vec g, InsertMode mode, Vec l)
    2968: {
    2969:   PetscSF                 sf;
    2970:   const PetscScalar      *gArray;
    2971:   PetscScalar            *lArray;
    2972:   PetscBool               transform;
    2973:   DMGlobalToLocalHookLink link;
    2974:   PetscMemType            lmtype, gmtype;

    2976:   PetscFunctionBegin;
    2978:   PetscCall(DMGetSectionSF(dm, &sf));
    2979:   PetscCall(DMHasBasisTransform(dm, &transform));
    2980:   if (sf) {
    2981:     PetscCheck(mode != ADD_VALUES, PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_OUTOFRANGE, "Invalid insertion mode %d", (int)mode);

    2983:     PetscCall(VecGetArrayAndMemType(l, &lArray, &lmtype));
    2984:     PetscCall(VecGetArrayReadAndMemType(g, &gArray, &gmtype));
    2985:     PetscCall(PetscSFBcastEnd(sf, MPIU_SCALAR, gArray, lArray, MPI_REPLACE));
    2986:     PetscCall(VecRestoreArrayAndMemType(l, &lArray));
    2987:     PetscCall(VecRestoreArrayReadAndMemType(g, &gArray));
    2988:     if (transform) PetscCall(DMPlexGlobalToLocalBasis(dm, l));
    2989:   } else {
    2990:     PetscUseTypeMethod(dm, globaltolocalend, g, mode == INSERT_ALL_VALUES ? INSERT_VALUES : (mode == ADD_ALL_VALUES ? ADD_VALUES : mode), l);
    2991:   }
    2992:   PetscCall(DMGlobalToLocalHook_Constraints(dm, g, mode, l, NULL));
    2993:   for (link = dm->gtolhook; link; link = link->next) {
    2994:     if (link->endhook) PetscCall((*link->endhook)(dm, g, mode, l, link->ctx));
    2995:   }
    2996:   PetscFunctionReturn(PETSC_SUCCESS);
    2997: }

    2999: /*@C
    3000:   DMLocalToGlobalHookAdd - adds a callback to be run when a local to global is called

    3002:   Logically Collective

    3004:   Input Parameters:
    3005: + dm        - the `DM`
    3006: . beginhook - function to run at the beginning of `DMLocalToGlobalBegin()`
    3007: . endhook   - function to run after `DMLocalToGlobalEnd()` has completed
    3008: - ctx       - [optional] context for provide data for the hooks (may be `NULL`)

    3010:   Calling sequence of `beginhook`:
    3011: + global - global `DM`
    3012: . l      - local vector
    3013: . mode   - mode
    3014: . g      - global vector
    3015: - ctx    - optional function context

    3017:   Calling sequence of `endhook`:
    3018: + global - global `DM`
    3019: . l      - local vector
    3020: . mode   - mode
    3021: . g      - global vector
    3022: - ctx    - optional function context

    3024:   Level: advanced

    3026: .seealso: [](ch_dmbase), `DM`, `DMLocalToGlobal()`, `DMRefineHookAdd()`, `DMGlobalToLocalHookAdd()`, `SNESFASGetInterpolation()`, `SNESFASGetInjection()`, `PetscObjectCompose()`, `PetscContainerCreate()`
    3027: @*/
    3028: PetscErrorCode DMLocalToGlobalHookAdd(DM dm, PetscErrorCode (*beginhook)(DM global, Vec l, InsertMode mode, Vec g, PetscCtx ctx), PetscErrorCode (*endhook)(DM global, Vec l, InsertMode mode, Vec g, PetscCtx ctx), PetscCtx ctx)
    3029: {
    3030:   DMLocalToGlobalHookLink link, *p;

    3032:   PetscFunctionBegin;
    3034:   for (p = &dm->ltoghook; *p; p = &(*p)->next) { } /* Scan to the end of the current list of hooks */
    3035:   PetscCall(PetscNew(&link));
    3036:   link->beginhook = beginhook;
    3037:   link->endhook   = endhook;
    3038:   link->ctx       = ctx;
    3039:   link->next      = NULL;
    3040:   *p              = link;
    3041:   PetscFunctionReturn(PETSC_SUCCESS);
    3042: }

    3044: static PetscErrorCode DMLocalToGlobalHook_Constraints(DM dm, Vec l, InsertMode mode, Vec g, PetscCtx ctx)
    3045: {
    3046:   PetscFunctionBegin;
    3047:   (void)g;
    3048:   (void)ctx;
    3050:   if (mode == ADD_VALUES || mode == ADD_ALL_VALUES || mode == ADD_BC_VALUES) {
    3051:     Mat          cMat;
    3052:     Vec          cVec;
    3053:     PetscInt     nRows;
    3054:     PetscSection section, cSec;
    3055:     PetscInt     pStart, pEnd, p, dof;

    3057:     PetscCall(DMGetDefaultConstraints(dm, &cSec, &cMat, NULL));
    3058:     if (!cMat) PetscFunctionReturn(PETSC_SUCCESS);

    3060:     PetscCall(MatGetSize(cMat, &nRows, NULL));
    3061:     if (nRows <= 0) PetscFunctionReturn(PETSC_SUCCESS);
    3062:     PetscCall(DMGetLocalSection(dm, &section));
    3063:     PetscCall(MatCreateVecs(cMat, NULL, &cVec));
    3064:     PetscCall(PetscSectionGetChart(cSec, &pStart, &pEnd));
    3065:     for (p = pStart; p < pEnd; p++) {
    3066:       PetscCall(PetscSectionGetDof(cSec, p, &dof));
    3067:       if (dof) {
    3068:         PetscInt     d;
    3069:         PetscScalar *vals;
    3070:         PetscCall(VecGetValuesSection(l, section, p, &vals));
    3071:         PetscCall(VecSetValuesSection(cVec, cSec, p, vals, mode));
    3072:         /* for this to be the true transpose, we have to zero the values that
    3073:          * we just extracted */
    3074:         for (d = 0; d < dof; d++) vals[d] = 0.;
    3075:       }
    3076:     }
    3077:     PetscCall(MatMultTransposeAdd(cMat, cVec, l, l));
    3078:     PetscCall(VecDestroy(&cVec));
    3079:   }
    3080:   PetscFunctionReturn(PETSC_SUCCESS);
    3081: }
    3082: /*@
    3083:   DMLocalToGlobal - updates global vectors from local vectors

    3085:   Neighbor-wise Collective

    3087:   Input Parameters:
    3088: + dm   - the `DM` object
    3089: . l    - the local vector
    3090: . mode - if `INSERT_VALUES` then no parallel communication is used, if `ADD_VALUES` then all ghost points from the same base point accumulate into that base point.
    3091: - g    - the global vector

    3093:   Level: beginner

    3095:   Notes:
    3096:   The communication involved in this update can be overlapped with computation by using
    3097:   `DMLocalToGlobalBegin()` and `DMLocalToGlobalEnd()`.

    3099:   In the `ADD_VALUES` case you normally would zero the receiving vector before beginning this operation.

    3101:   `INSERT_VALUES` is not supported for `DMDA`; in that case simply compute the values directly into a global vector instead of a local one.

    3103:   Use `DMLocalToGlobalHookAdd()` to add additional operations that are performed on the data during the update process

    3105: .seealso: [](ch_dmbase), `DM`, `DMLocalToGlobalBegin()`, `DMLocalToGlobalEnd()`, `DMCoarsen()`, `DMDestroy()`, `DMView()`, `DMCreateGlobalVector()`, `DMCreateInterpolation()`, `DMGlobalToLocal()`, `DMGlobalToLocalEnd()`, `DMGlobalToLocalBegin()`, `DMLocalToGlobalHookAdd()`, `DMGlobaToLocallHookAdd()`
    3106: @*/
    3107: PetscErrorCode DMLocalToGlobal(DM dm, Vec l, InsertMode mode, Vec g)
    3108: {
    3109:   PetscFunctionBegin;
    3110:   PetscCall(DMLocalToGlobalBegin(dm, l, mode, g));
    3111:   PetscCall(DMLocalToGlobalEnd(dm, l, mode, g));
    3112:   PetscFunctionReturn(PETSC_SUCCESS);
    3113: }

    3115: /*@
    3116:   DMLocalToGlobalBegin - begins updating global vectors from local vectors

    3118:   Neighbor-wise Collective

    3120:   Input Parameters:
    3121: + dm   - the `DM` object
    3122: . l    - the local vector
    3123: . mode - if `INSERT_VALUES` then no parallel communication is used, if `ADD_VALUES` then all ghost points from the same base point accumulate into that base point.
    3124: - g    - the global vector

    3126:   Level: intermediate

    3128:   Notes:
    3129:   In the `ADD_VALUES` case you normally would zero the receiving vector before beginning this operation.

    3131:   `INSERT_VALUES is` not supported for `DMDA`, in that case simply compute the values directly into a global vector instead of a local one.

    3133:   Use `DMLocalToGlobalEnd()` to complete the communication process.

    3135:   `DMLocalToGlobal()` is a short form of  `DMLocalToGlobalBegin()` and  `DMLocalToGlobalEnd()`

    3137:   `DMLocalToGlobalHookAdd()` may be used to provide additional operations that are performed during the update process.

    3139: .seealso: [](ch_dmbase), `DM`, `DMLocalToGlobal()`, `DMLocalToGlobalEnd()`, `DMCoarsen()`, `DMDestroy()`, `DMView()`, `DMCreateGlobalVector()`, `DMCreateInterpolation()`, `DMGlobalToLocal()`, `DMGlobalToLocalEnd()`, `DMGlobalToLocalBegin()`
    3140: @*/
    3141: PetscErrorCode DMLocalToGlobalBegin(DM dm, Vec l, InsertMode mode, Vec g)
    3142: {
    3143:   PetscSF                 sf;
    3144:   PetscSection            s, gs;
    3145:   DMLocalToGlobalHookLink link;
    3146:   Vec                     tmpl;
    3147:   const PetscScalar      *lArray;
    3148:   PetscScalar            *gArray;
    3149:   PetscBool               isInsert, transform, l_inplace = PETSC_FALSE, g_inplace = PETSC_FALSE;
    3150:   PetscMemType            lmtype = PETSC_MEMTYPE_HOST, gmtype = PETSC_MEMTYPE_HOST;

    3152:   PetscFunctionBegin;
    3154:   for (link = dm->ltoghook; link; link = link->next) {
    3155:     if (link->beginhook) PetscCall((*link->beginhook)(dm, l, mode, g, link->ctx));
    3156:   }
    3157:   PetscCall(DMLocalToGlobalHook_Constraints(dm, l, mode, g, NULL));
    3158:   PetscCall(DMGetSectionSF(dm, &sf));
    3159:   PetscCall(DMGetLocalSection(dm, &s));
    3160:   switch (mode) {
    3161:   case INSERT_VALUES:
    3162:   case INSERT_ALL_VALUES:
    3163:   case INSERT_BC_VALUES:
    3164:     isInsert = PETSC_TRUE;
    3165:     break;
    3166:   case ADD_VALUES:
    3167:   case ADD_ALL_VALUES:
    3168:   case ADD_BC_VALUES:
    3169:     isInsert = PETSC_FALSE;
    3170:     break;
    3171:   default:
    3172:     SETERRQ(PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_OUTOFRANGE, "Invalid insertion mode %d", mode);
    3173:   }
    3174:   if ((sf && !isInsert) || (s && isInsert)) {
    3175:     PetscCall(DMHasBasisTransform(dm, &transform));
    3176:     if (transform) {
    3177:       PetscCall(DMGetNamedLocalVector(dm, "__petsc_dm_transform_local_copy", &tmpl));
    3178:       PetscCall(VecCopy(l, tmpl));
    3179:       PetscCall(DMPlexLocalToGlobalBasis(dm, tmpl));
    3180:       PetscCall(VecGetArrayRead(tmpl, &lArray));
    3181:     } else if (isInsert) {
    3182:       PetscCall(VecGetArrayRead(l, &lArray));
    3183:     } else {
    3184:       PetscCall(VecGetArrayReadAndMemType(l, &lArray, &lmtype));
    3185:       l_inplace = PETSC_TRUE;
    3186:     }
    3187:     if (s && isInsert) {
    3188:       PetscCall(VecGetArray(g, &gArray));
    3189:     } else {
    3190:       PetscCall(VecGetArrayAndMemType(g, &gArray, &gmtype));
    3191:       g_inplace = PETSC_TRUE;
    3192:     }
    3193:     if (sf && !isInsert) {
    3194:       PetscCall(PetscSFReduceWithMemTypeBegin(sf, MPIU_SCALAR, lmtype, lArray, gmtype, gArray, MPIU_SUM));
    3195:     } else if (s && isInsert) {
    3196:       PetscInt gStart, pStart, pEnd, p;

    3198:       PetscCall(DMGetGlobalSection(dm, &gs));
    3199:       PetscCall(PetscSectionGetChart(s, &pStart, &pEnd));
    3200:       PetscCall(VecGetOwnershipRange(g, &gStart, NULL));
    3201:       for (p = pStart; p < pEnd; ++p) {
    3202:         PetscInt dof, gdof, cdof, gcdof, off, goff, d, e;

    3204:         PetscCall(PetscSectionGetDof(s, p, &dof));
    3205:         PetscCall(PetscSectionGetDof(gs, p, &gdof));
    3206:         PetscCall(PetscSectionGetConstraintDof(s, p, &cdof));
    3207:         PetscCall(PetscSectionGetConstraintDof(gs, p, &gcdof));
    3208:         PetscCall(PetscSectionGetOffset(s, p, &off));
    3209:         PetscCall(PetscSectionGetOffset(gs, p, &goff));
    3210:         /* Ignore off-process data and points with no global data */
    3211:         if (!gdof || goff < 0) continue;
    3212:         PetscCheck(dof == gdof, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Inconsistent sizes, p: %" PetscInt_FMT " dof: %" PetscInt_FMT " gdof: %" PetscInt_FMT " cdof: %" PetscInt_FMT " gcdof: %" PetscInt_FMT, p, dof, gdof, cdof, gcdof);
    3213:         /* If no constraints are enforced in the global vector */
    3214:         if (!gcdof) {
    3215:           for (d = 0; d < dof; ++d) gArray[goff - gStart + d] = lArray[off + d];
    3216:           /* If constraints are enforced in the global vector */
    3217:         } else if (cdof == gcdof) {
    3218:           const PetscInt *cdofs;
    3219:           PetscInt        cind = 0;

    3221:           PetscCall(PetscSectionGetConstraintIndices(s, p, &cdofs));
    3222:           for (d = 0, e = 0; d < dof; ++d) {
    3223:             if ((cind < cdof) && (d == cdofs[cind])) {
    3224:               ++cind;
    3225:               continue;
    3226:             }
    3227:             gArray[goff - gStart + e++] = lArray[off + d];
    3228:           }
    3229:         } else SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Inconsistent sizes, p: %" PetscInt_FMT " dof: %" PetscInt_FMT " gdof: %" PetscInt_FMT " cdof: %" PetscInt_FMT " gcdof: %" PetscInt_FMT, p, dof, gdof, cdof, gcdof);
    3230:       }
    3231:     }
    3232:     if (g_inplace) {
    3233:       PetscCall(VecRestoreArrayAndMemType(g, &gArray));
    3234:     } else {
    3235:       PetscCall(VecRestoreArray(g, &gArray));
    3236:     }
    3237:     if (transform) {
    3238:       PetscCall(VecRestoreArrayRead(tmpl, &lArray));
    3239:       PetscCall(DMRestoreNamedLocalVector(dm, "__petsc_dm_transform_local_copy", &tmpl));
    3240:     } else if (l_inplace) {
    3241:       PetscCall(VecRestoreArrayReadAndMemType(l, &lArray));
    3242:     } else {
    3243:       PetscCall(VecRestoreArrayRead(l, &lArray));
    3244:     }
    3245:   } else {
    3246:     PetscUseTypeMethod(dm, localtoglobalbegin, l, mode == INSERT_ALL_VALUES ? INSERT_VALUES : (mode == ADD_ALL_VALUES ? ADD_VALUES : mode), g);
    3247:   }
    3248:   PetscFunctionReturn(PETSC_SUCCESS);
    3249: }

    3251: /*@
    3252:   DMLocalToGlobalEnd - updates global vectors from local vectors

    3254:   Neighbor-wise Collective

    3256:   Input Parameters:
    3257: + dm   - the `DM` object
    3258: . l    - the local vector
    3259: . mode - `INSERT_VALUES` or `ADD_VALUES`
    3260: - g    - the global vector

    3262:   Level: intermediate

    3264:   Note:
    3265:   See `DMLocalToGlobalBegin()` for full details

    3267: .seealso: [](ch_dmbase), `DM`, `DMLocalToGlobalBegin()`, `DMCoarsen()`, `DMDestroy()`, `DMView()`, `DMCreateGlobalVector()`, `DMCreateInterpolation()`, `DMGlobalToLocalEnd()`
    3268: @*/
    3269: PetscErrorCode DMLocalToGlobalEnd(DM dm, Vec l, InsertMode mode, Vec g)
    3270: {
    3271:   PetscSF                 sf;
    3272:   PetscSection            s;
    3273:   DMLocalToGlobalHookLink link;
    3274:   PetscBool               isInsert, transform;

    3276:   PetscFunctionBegin;
    3278:   PetscCall(DMGetSectionSF(dm, &sf));
    3279:   PetscCall(DMGetLocalSection(dm, &s));
    3280:   switch (mode) {
    3281:   case INSERT_VALUES:
    3282:   case INSERT_ALL_VALUES:
    3283:     isInsert = PETSC_TRUE;
    3284:     break;
    3285:   case ADD_VALUES:
    3286:   case ADD_ALL_VALUES:
    3287:     isInsert = PETSC_FALSE;
    3288:     break;
    3289:   default:
    3290:     SETERRQ(PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_OUTOFRANGE, "Invalid insertion mode %d", mode);
    3291:   }
    3292:   if (sf && !isInsert) {
    3293:     const PetscScalar *lArray;
    3294:     PetscScalar       *gArray;
    3295:     Vec                tmpl;

    3297:     PetscCall(DMHasBasisTransform(dm, &transform));
    3298:     if (transform) {
    3299:       PetscCall(DMGetNamedLocalVector(dm, "__petsc_dm_transform_local_copy", &tmpl));
    3300:       PetscCall(VecGetArrayRead(tmpl, &lArray));
    3301:     } else {
    3302:       PetscCall(VecGetArrayReadAndMemType(l, &lArray, NULL));
    3303:     }
    3304:     PetscCall(VecGetArrayAndMemType(g, &gArray, NULL));
    3305:     PetscCall(PetscSFReduceEnd(sf, MPIU_SCALAR, lArray, gArray, MPIU_SUM));
    3306:     if (transform) {
    3307:       PetscCall(VecRestoreArrayRead(tmpl, &lArray));
    3308:       PetscCall(DMRestoreNamedLocalVector(dm, "__petsc_dm_transform_local_copy", &tmpl));
    3309:     } else {
    3310:       PetscCall(VecRestoreArrayReadAndMemType(l, &lArray));
    3311:     }
    3312:     PetscCall(VecRestoreArrayAndMemType(g, &gArray));
    3313:   } else if (s && isInsert) {
    3314:   } else {
    3315:     PetscUseTypeMethod(dm, localtoglobalend, l, mode == INSERT_ALL_VALUES ? INSERT_VALUES : (mode == ADD_ALL_VALUES ? ADD_VALUES : mode), g);
    3316:   }
    3317:   for (link = dm->ltoghook; link; link = link->next) {
    3318:     if (link->endhook) PetscCall((*link->endhook)(dm, g, mode, l, link->ctx));
    3319:   }
    3320:   PetscFunctionReturn(PETSC_SUCCESS);
    3321: }

    3323: /*@
    3324:   DMLocalToLocalBegin - Begins the process of mapping values from a local vector (that include
    3325:   ghost points that contain irrelevant values) to another local vector where the ghost points
    3326:   in the second are set correctly from values on other MPI ranks.

    3328:   Neighbor-wise Collective

    3330:   Input Parameters:
    3331: + dm   - the `DM` object
    3332: . g    - the original local vector
    3333: - mode - one of `INSERT_VALUES` or `ADD_VALUES`

    3335:   Output Parameter:
    3336: . l - the local vector with correct ghost values

    3338:   Level: intermediate

    3340:   Note:
    3341:   Must be followed by `DMLocalToLocalEnd()`.

    3343: .seealso: [](ch_dmbase), `DM`, `DMLocalToLocalEnd()`, `DMCoarsen()`, `DMDestroy()`, `DMView()`, `DMCreateLocalVector()`, `DMCreateGlobalVector()`, `DMCreateInterpolation()`, `DMGlobalToLocalEnd()`, `DMLocalToGlobalBegin()`
    3344: @*/
    3345: PetscErrorCode DMLocalToLocalBegin(DM dm, Vec g, InsertMode mode, Vec l)
    3346: {
    3347:   PetscFunctionBegin;
    3351:   PetscUseTypeMethod(dm, localtolocalbegin, g, mode == INSERT_ALL_VALUES ? INSERT_VALUES : (mode == ADD_ALL_VALUES ? ADD_VALUES : mode), l);
    3352:   PetscFunctionReturn(PETSC_SUCCESS);
    3353: }

    3355: /*@
    3356:   DMLocalToLocalEnd - Maps from a local vector to another local vector where the ghost
    3357:   points in the second are set correctly. Must be preceded by `DMLocalToLocalBegin()`.

    3359:   Neighbor-wise Collective

    3361:   Input Parameters:
    3362: + dm   - the `DM` object
    3363: . g    - the original local vector
    3364: - mode - one of `INSERT_VALUES` or `ADD_VALUES`

    3366:   Output Parameter:
    3367: . l - the local vector with correct ghost values

    3369:   Level: intermediate

    3371: .seealso: [](ch_dmbase), `DM`, `DMLocalToLocalBegin()`, `DMCoarsen()`, `DMDestroy()`, `DMView()`, `DMCreateLocalVector()`, `DMCreateGlobalVector()`, `DMCreateInterpolation()`, `DMGlobalToLocalEnd()`, `DMLocalToGlobalBegin()`
    3372: @*/
    3373: PetscErrorCode DMLocalToLocalEnd(DM dm, Vec g, InsertMode mode, Vec l)
    3374: {
    3375:   PetscFunctionBegin;
    3379:   PetscUseTypeMethod(dm, localtolocalend, g, mode == INSERT_ALL_VALUES ? INSERT_VALUES : (mode == ADD_ALL_VALUES ? ADD_VALUES : mode), l);
    3380:   PetscFunctionReturn(PETSC_SUCCESS);
    3381: }

    3383: /*@
    3384:   DMCoarsen - Coarsens a `DM` object using a standard, non-adaptive coarsening of the underlying mesh

    3386:   Collective

    3388:   Input Parameters:
    3389: + dm   - the `DM` object
    3390: - comm - the communicator to contain the new `DM` object (or `MPI_COMM_NULL`)

    3392:   Output Parameter:
    3393: . dmc - the coarsened `DM`

    3395:   Level: developer

    3397: .seealso: [](ch_dmbase), `DM`, `DMRefine()`, `DMDestroy()`, `DMView()`, `DMCreateGlobalVector()`, `DMCreateInterpolation()`, `DMCreateDomainDecomposition()`,
    3398:           `DMCoarsenHookAdd()`, `DMCoarsenHookRemove()`
    3399: @*/
    3400: PetscErrorCode DMCoarsen(DM dm, MPI_Comm comm, DM *dmc)
    3401: {
    3402:   DMCoarsenHookLink link;

    3404:   PetscFunctionBegin;
    3406:   PetscCall(PetscLogEventBegin(DM_Coarsen, dm, 0, 0, 0));
    3407:   PetscUseTypeMethod(dm, coarsen, comm, dmc);
    3408:   if (*dmc) {
    3409:     (*dmc)->bind_below = dm->bind_below; /* Propagate this from parent DM; otherwise -dm_bind_below will be useless for multigrid cases. */
    3410:     PetscCall(DMSetCoarseDM(dm, *dmc));
    3411:     (*dmc)->ops->creatematrix = dm->ops->creatematrix;
    3412:     PetscCall(PetscObjectCopyFortranFunctionPointers((PetscObject)dm, (PetscObject)*dmc));
    3413:     (*dmc)->ctx       = dm->ctx;
    3414:     (*dmc)->levelup   = dm->levelup;
    3415:     (*dmc)->leveldown = dm->leveldown + 1;
    3416:     PetscCall(DMSetMatType(*dmc, dm->mattype));
    3417:     for (link = dm->coarsenhook; link; link = link->next) {
    3418:       if (link->coarsenhook) PetscCall((*link->coarsenhook)(dm, *dmc, link->ctx));
    3419:     }
    3420:   }
    3421:   PetscCall(PetscLogEventEnd(DM_Coarsen, dm, 0, 0, 0));
    3422:   PetscCheck(*dmc, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "NULL coarse mesh produced");
    3423:   PetscFunctionReturn(PETSC_SUCCESS);
    3424: }

    3426: /*@C
    3427:   DMCoarsenHookAdd - adds a callback to be run when restricting a nonlinear problem to the coarse grid

    3429:   Logically Collective; No Fortran Support

    3431:   Input Parameters:
    3432: + fine         - `DM` on which to run a hook when restricting to a coarser level
    3433: . coarsenhook  - function to run when setting up a coarser level
    3434: . restricthook - function to run to update data on coarser levels (called once per `SNESSolve()`)
    3435: - ctx          - [optional] application context for provide data for the hooks (may be `NULL`)

    3437:   Calling sequence of `coarsenhook`:
    3438: + fine   - fine level `DM`
    3439: . coarse - coarse level `DM` to restrict problem to
    3440: - ctx    - optional application function context

    3442:   Calling sequence of `restricthook`:
    3443: + fine      - fine level `DM`
    3444: . mrestrict - matrix restricting a fine-level solution to the coarse grid, usually the transpose of the interpolation
    3445: . rscale    - scaling vector for restriction
    3446: . inject    - matrix restricting by injection
    3447: . coarse    - coarse level DM to update
    3448: - ctx       - optional application function context

    3450:   Level: advanced

    3452:   Notes:
    3453:   This function is only needed if auxiliary data, attached to the `DM` with `PetscObjectCompose()`, needs to be set up or passed from the fine `DM` to the coarse `DM`.

    3455:   If this function is called multiple times, the hooks will be run in the order they are added.

    3457:   In order to compose with nonlinear preconditioning without duplicating storage, the hook should be implemented to
    3458:   extract the finest level information from its context (instead of from the `SNES`).

    3460:   The hooks are automatically called by `DMRestrict()`

    3462: .seealso: [](ch_dmbase), `DM`, `DMCoarsenHookRemove()`, `DMRefineHookAdd()`, `SNESFASGetInterpolation()`, `SNESFASGetInjection()`, `PetscObjectCompose()`, `PetscContainerCreate()`
    3463: @*/
    3464: PetscErrorCode DMCoarsenHookAdd(DM fine, PetscErrorCode (*coarsenhook)(DM fine, DM coarse, PetscCtx ctx), PetscErrorCode (*restricthook)(DM fine, Mat mrestrict, Vec rscale, Mat inject, DM coarse, PetscCtx ctx), PetscCtx ctx)
    3465: {
    3466:   DMCoarsenHookLink link, *p;

    3468:   PetscFunctionBegin;
    3470:   for (p = &fine->coarsenhook; *p; p = &(*p)->next) { /* Scan to the end of the current list of hooks */
    3471:     if ((*p)->coarsenhook == coarsenhook && (*p)->restricthook == restricthook && (*p)->ctx == ctx) PetscFunctionReturn(PETSC_SUCCESS);
    3472:   }
    3473:   PetscCall(PetscNew(&link));
    3474:   link->coarsenhook  = coarsenhook;
    3475:   link->restricthook = restricthook;
    3476:   link->ctx          = ctx;
    3477:   link->next         = NULL;
    3478:   *p                 = link;
    3479:   PetscFunctionReturn(PETSC_SUCCESS);
    3480: }

    3482: /*@C
    3483:   DMCoarsenHookRemove - remove a callback set with `DMCoarsenHookAdd()`

    3485:   Logically Collective; No Fortran Support

    3487:   Input Parameters:
    3488: + fine         - `DM` on which to run a hook when restricting to a coarser level
    3489: . coarsenhook  - function to run when setting up a coarser level
    3490: . restricthook - function to run to update data on coarser levels
    3491: - ctx          - [optional] application context for provide data for the hooks (may be `NULL`)

    3493:   Calling sequence of `coarsenhook`:
    3494: + fine   - fine level `DM`
    3495: . coarse - coarse level `DM` to restrict problem to
    3496: - ctx    - optional application function context

    3498:   Calling sequence of `restricthook`:
    3499: + fine    - fine level `DM`
    3500: . rstrict - matrix restricting a fine-level solution to the coarse grid, usually the transpose of the interpolation
    3501: . rscale  - scaling vector for restriction
    3502: . inject  - matrix restricting by injection
    3503: . coarse  - coarse level DM to update
    3504: - ctx     - optional application function context

    3506:   Level: advanced

    3508:   Notes:
    3509:   This function does nothing if the `coarsenhook` is not in the list.

    3511:   See `DMCoarsenHookAdd()` for the calling sequence of `coarsenhook` and `restricthook`

    3513: .seealso: [](ch_dmbase), `DM`, `DMCoarsenHookAdd()`, `DMRefineHookAdd()`, `SNESFASGetInterpolation()`, `SNESFASGetInjection()`, `PetscObjectCompose()`, `PetscContainerCreate()`
    3514: @*/
    3515: PetscErrorCode DMCoarsenHookRemove(DM fine, PetscErrorCode (*coarsenhook)(DM fine, DM coarse, PetscCtx ctx), PetscErrorCode (*restricthook)(DM fine, Mat rstrict, Vec rscale, Mat inject, DM coarse, PetscCtx ctx), PetscCtx ctx)
    3516: {
    3517:   DMCoarsenHookLink link, *p;

    3519:   PetscFunctionBegin;
    3521:   for (p = &fine->coarsenhook; *p; p = &(*p)->next) { /* Search the list of current hooks */
    3522:     if ((*p)->coarsenhook == coarsenhook && (*p)->restricthook == restricthook && (*p)->ctx == ctx) {
    3523:       link = *p;
    3524:       *p   = link->next;
    3525:       PetscCall(PetscFree(link));
    3526:       break;
    3527:     }
    3528:   }
    3529:   PetscFunctionReturn(PETSC_SUCCESS);
    3530: }

    3532: /*@
    3533:   DMRestrict - restricts user-defined problem data to a coarser `DM` by running hooks registered by `DMCoarsenHookAdd()`

    3535:   Collective if any hooks are

    3537:   Input Parameters:
    3538: + fine    - finer `DM` from which the data is obtained
    3539: . restrct - restriction matrix, apply using `MatRestrict()`, usually the transpose of the interpolation
    3540: . rscale  - scaling vector for restriction
    3541: . inject  - injection matrix, also use `MatRestrict()`
    3542: - coarse  - coarser `DM` to update

    3544:   Level: developer

    3546:   Developer Note:
    3547:   Though this routine is called `DMRestrict()` the hooks are added with `DMCoarsenHookAdd()`, a consistent terminology would be better

    3549: .seealso: [](ch_dmbase), `DM`, `DMCoarsenHookAdd()`, `MatRestrict()`, `DMInterpolate()`, `DMRefineHookAdd()`
    3550: @*/
    3551: PetscErrorCode DMRestrict(DM fine, Mat restrct, Vec rscale, Mat inject, DM coarse)
    3552: {
    3553:   DMCoarsenHookLink link;

    3555:   PetscFunctionBegin;
    3556:   for (link = fine->coarsenhook; link; link = link->next) {
    3557:     if (link->restricthook) PetscCall((*link->restricthook)(fine, restrct, rscale, inject, coarse, link->ctx));
    3558:   }
    3559:   PetscFunctionReturn(PETSC_SUCCESS);
    3560: }

    3562: /*@C
    3563:   DMSubDomainHookAdd - adds a callback to be run when restricting a problem to subdomain `DM`s with `DMCreateDomainDecomposition()`

    3565:   Logically Collective; No Fortran Support

    3567:   Input Parameters:
    3568: + global       - global `DM`
    3569: . ddhook       - function to run to pass data to the decomposition `DM` upon its creation
    3570: . restricthook - function to run to update data on block solve (at the beginning of the block solve)
    3571: - ctx          - [optional] application context for provide data for the hooks (may be `NULL`)

    3573:   Calling sequence of `ddhook`:
    3574: + global - global `DM`
    3575: . block  - subdomain `DM`
    3576: - ctx    - optional application function context

    3578:   Calling sequence of `restricthook`:
    3579: + global - global `DM`
    3580: . out    - scatter to the outer (with ghost and overlap points) sub vector
    3581: . in     - scatter to sub vector values only owned locally
    3582: . block  - subdomain `DM`
    3583: - ctx    - optional application function context

    3585:   Level: advanced

    3587:   Notes:
    3588:   This function can be used if auxiliary data needs to be set up on subdomain `DM`s.

    3590:   If this function is called multiple times, the hooks will be run in the order they are added.

    3592:   In order to compose with nonlinear preconditioning without duplicating storage, the hook should be implemented to
    3593:   extract the global information from its context (instead of from the `SNES`).

    3595:   Developer Note:
    3596:   It is unclear what "block solve" means within the definition of `restricthook`

    3598: .seealso: [](ch_dmbase), `DM`, `DMSubDomainHookRemove()`, `DMRefineHookAdd()`, `SNESFASGetInterpolation()`, `SNESFASGetInjection()`, `PetscObjectCompose()`, `PetscContainerCreate()`, `DMCreateDomainDecomposition()`
    3599: @*/
    3600: PetscErrorCode DMSubDomainHookAdd(DM global, PetscErrorCode (*ddhook)(DM global, DM block, PetscCtx ctx), PetscErrorCode (*restricthook)(DM global, VecScatter out, VecScatter in, DM block, PetscCtx ctx), PetscCtx ctx)
    3601: {
    3602:   DMSubDomainHookLink link, *p;

    3604:   PetscFunctionBegin;
    3606:   for (p = &global->subdomainhook; *p; p = &(*p)->next) { /* Scan to the end of the current list of hooks */
    3607:     if ((*p)->ddhook == ddhook && (*p)->restricthook == restricthook && (*p)->ctx == ctx) PetscFunctionReturn(PETSC_SUCCESS);
    3608:   }
    3609:   PetscCall(PetscNew(&link));
    3610:   link->restricthook = restricthook;
    3611:   link->ddhook       = ddhook;
    3612:   link->ctx          = ctx;
    3613:   link->next         = NULL;
    3614:   *p                 = link;
    3615:   PetscFunctionReturn(PETSC_SUCCESS);
    3616: }

    3618: /*@C
    3619:   DMSubDomainHookRemove - remove a callback from the list to be run when restricting a problem to subdomain `DM`s with `DMCreateDomainDecomposition()`

    3621:   Logically Collective; No Fortran Support

    3623:   Input Parameters:
    3624: + global       - global `DM`
    3625: . ddhook       - function to run to pass data to the decomposition `DM` upon its creation
    3626: . restricthook - function to run to update data on block solve (at the beginning of the block solve)
    3627: - ctx          - [optional] application context for provide data for the hooks (may be `NULL`)

    3629:   Calling sequence of `ddhook`:
    3630: + dm    - global `DM`
    3631: . block - subdomain `DM`
    3632: - ctx   - optional application function context

    3634:   Calling sequence of `restricthook`:
    3635: + dm       - global `DM`
    3636: . oscatter - scatter to the outer (with ghost and overlap points) sub vector
    3637: . gscatter - scatter to sub vector values only owned locally
    3638: . block    - subdomain `DM`
    3639: - ctx      - optional application function context

    3641:   Level: advanced

    3643: .seealso: [](ch_dmbase), `DM`, `DMSubDomainHookAdd()`, `SNESFASGetInterpolation()`, `SNESFASGetInjection()`, `PetscObjectCompose()`, `PetscContainerCreate()`,
    3644:           `DMCreateDomainDecomposition()`
    3645: @*/
    3646: PetscErrorCode DMSubDomainHookRemove(DM global, PetscErrorCode (*ddhook)(DM dm, DM block, PetscCtx ctx), PetscErrorCode (*restricthook)(DM dm, VecScatter oscatter, VecScatter gscatter, DM block, PetscCtx ctx), PetscCtx ctx)
    3647: {
    3648:   DMSubDomainHookLink link, *p;

    3650:   PetscFunctionBegin;
    3652:   for (p = &global->subdomainhook; *p; p = &(*p)->next) { /* Search the list of current hooks */
    3653:     if ((*p)->ddhook == ddhook && (*p)->restricthook == restricthook && (*p)->ctx == ctx) {
    3654:       link = *p;
    3655:       *p   = link->next;
    3656:       PetscCall(PetscFree(link));
    3657:       break;
    3658:     }
    3659:   }
    3660:   PetscFunctionReturn(PETSC_SUCCESS);
    3661: }

    3663: /*@
    3664:   DMSubDomainRestrict - restricts user-defined problem data to a subdomain `DM` by running hooks registered by `DMSubDomainHookAdd()`

    3666:   Collective if any hooks are

    3668:   Input Parameters:
    3669: + global   - The global `DM` to use as a base
    3670: . oscatter - The scatter from domain global vector filling subdomain global vector with overlap
    3671: . gscatter - The scatter from domain global vector filling subdomain local vector with ghosts
    3672: - subdm    - The subdomain `DM` to update

    3674:   Level: developer

    3676: .seealso: [](ch_dmbase), `DM`, `DMCoarsenHookAdd()`, `MatRestrict()`, `DMCreateDomainDecomposition()`
    3677: @*/
    3678: PetscErrorCode DMSubDomainRestrict(DM global, VecScatter oscatter, VecScatter gscatter, DM subdm)
    3679: {
    3680:   DMSubDomainHookLink link;

    3682:   PetscFunctionBegin;
    3683:   for (link = global->subdomainhook; link; link = link->next) {
    3684:     if (link->restricthook) PetscCall((*link->restricthook)(global, oscatter, gscatter, subdm, link->ctx));
    3685:   }
    3686:   PetscFunctionReturn(PETSC_SUCCESS);
    3687: }

    3689: /*@
    3690:   DMGetCoarsenLevel - Gets the number of coarsenings that have generated this `DM`.

    3692:   Not Collective

    3694:   Input Parameter:
    3695: . dm - the `DM` object

    3697:   Output Parameter:
    3698: . level - number of coarsenings

    3700:   Level: developer

    3702: .seealso: [](ch_dmbase), `DM`, `DMCoarsen()`, `DMSetCoarsenLevel()`, `DMGetRefineLevel()`, `DMDestroy()`, `DMView()`, `DMCreateGlobalVector()`, `DMCreateInterpolation()`
    3703: @*/
    3704: PetscErrorCode DMGetCoarsenLevel(DM dm, PetscInt *level)
    3705: {
    3706:   PetscFunctionBegin;
    3708:   PetscAssertPointer(level, 2);
    3709:   *level = dm->leveldown;
    3710:   PetscFunctionReturn(PETSC_SUCCESS);
    3711: }

    3713: /*@
    3714:   DMSetCoarsenLevel - Sets the number of coarsenings that have generated this `DM`.

    3716:   Collective

    3718:   Input Parameters:
    3719: + dm    - the `DM` object
    3720: - level - number of coarsenings

    3722:   Level: developer

    3724:   Note:
    3725:   This is rarely used directly, the information is automatically set when a `DM` is created with `DMCoarsen()`

    3727: .seealso: [](ch_dmbase), `DM`, `DMCoarsen()`, `DMGetCoarsenLevel()`, `DMGetRefineLevel()`, `DMDestroy()`, `DMView()`, `DMCreateGlobalVector()`, `DMCreateInterpolation()`
    3728: @*/
    3729: PetscErrorCode DMSetCoarsenLevel(DM dm, PetscInt level)
    3730: {
    3731:   PetscFunctionBegin;
    3733:   dm->leveldown = level;
    3734:   PetscFunctionReturn(PETSC_SUCCESS);
    3735: }

    3737: /*@
    3738:   DMRefineHierarchy - Refines a `DM` object, all levels at once

    3740:   Collective

    3742:   Input Parameters:
    3743: + dm      - the `DM` object
    3744: - nlevels - the number of levels of refinement

    3746:   Output Parameter:
    3747: . dmf - the refined `DM` hierarchy

    3749:   Level: developer

    3751: .seealso: [](ch_dmbase), `DM`, `DMCoarsen()`, `DMCoarsenHierarchy()`, `DMDestroy()`, `DMView()`, `DMCreateGlobalVector()`, `DMCreateInterpolation()`
    3752: @*/
    3753: PetscErrorCode DMRefineHierarchy(DM dm, PetscInt nlevels, DM dmf[])
    3754: {
    3755:   PetscFunctionBegin;
    3757:   PetscCheck(nlevels >= 0, PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_OUTOFRANGE, "nlevels cannot be negative");
    3758:   if (nlevels == 0) PetscFunctionReturn(PETSC_SUCCESS);
    3759:   PetscAssertPointer(dmf, 3);
    3760:   if (dm->ops->refine && !dm->ops->refinehierarchy) {
    3761:     PetscInt i;

    3763:     PetscCall(DMRefine(dm, PetscObjectComm((PetscObject)dm), &dmf[0]));
    3764:     for (i = 1; i < nlevels; i++) PetscCall(DMRefine(dmf[i - 1], PetscObjectComm((PetscObject)dm), &dmf[i]));
    3765:   } else PetscUseTypeMethod(dm, refinehierarchy, nlevels, dmf);
    3766:   PetscFunctionReturn(PETSC_SUCCESS);
    3767: }

    3769: /*@
    3770:   DMCoarsenHierarchy - Coarsens a `DM` object, all levels at once

    3772:   Collective

    3774:   Input Parameters:
    3775: + dm      - the `DM` object
    3776: - nlevels - the number of levels of coarsening

    3778:   Output Parameter:
    3779: . dmc - the coarsened `DM` hierarchy

    3781:   Level: developer

    3783: .seealso: [](ch_dmbase), `DM`, `DMCoarsen()`, `DMRefineHierarchy()`, `DMDestroy()`, `DMView()`, `DMCreateGlobalVector()`, `DMCreateInterpolation()`
    3784: @*/
    3785: PetscErrorCode DMCoarsenHierarchy(DM dm, PetscInt nlevels, DM dmc[])
    3786: {
    3787:   PetscFunctionBegin;
    3789:   PetscCheck(nlevels >= 0, PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_OUTOFRANGE, "nlevels cannot be negative");
    3790:   if (nlevels == 0) PetscFunctionReturn(PETSC_SUCCESS);
    3791:   PetscAssertPointer(dmc, 3);
    3792:   if (dm->ops->coarsen && !dm->ops->coarsenhierarchy) {
    3793:     PetscInt i;

    3795:     PetscCall(DMCoarsen(dm, PetscObjectComm((PetscObject)dm), &dmc[0]));
    3796:     for (i = 1; i < nlevels; i++) PetscCall(DMCoarsen(dmc[i - 1], PetscObjectComm((PetscObject)dm), &dmc[i]));
    3797:   } else PetscUseTypeMethod(dm, coarsenhierarchy, nlevels, dmc);
    3798:   PetscFunctionReturn(PETSC_SUCCESS);
    3799: }

    3801: /*@C
    3802:   DMSetApplicationContextDestroy - Sets a user function that will be called to destroy the application context when the `DM` is destroyed

    3804:   Logically Collective if the function is collective

    3806:   Input Parameters:
    3807: + dm      - the `DM` object
    3808: - destroy - the destroy function, see `PetscCtxDestroyFn` for the calling sequence

    3810:   Level: intermediate

    3812: .seealso: [](ch_dmbase), `DM`, `DMSetApplicationContext()`, `DMView()`, `DMCreateGlobalVector()`, `DMCreateInterpolation()`, `DMCreateColoring()`, `DMCreateMatrix()`, `DMCreateMassMatrix()`,
    3813:           `DMGetApplicationContext()`, `PetscCtxDestroyFn`
    3814: @*/
    3815: PetscErrorCode DMSetApplicationContextDestroy(DM dm, PetscCtxDestroyFn *destroy)
    3816: {
    3817:   PetscFunctionBegin;
    3819:   dm->ctxdestroy = destroy;
    3820:   PetscFunctionReturn(PETSC_SUCCESS);
    3821: }

    3823: /*@
    3824:   DMSetApplicationContext - Set an application context into a `DM` object

    3826:   Not Collective

    3828:   Input Parameters:
    3829: + dm  - the `DM` object
    3830: - ctx - the application context

    3832:   Level: intermediate

    3834:   Note:
    3835:   An application context is a way to pass problem specific information that is accessible whenever the `DM` is available
    3836:   In a multilevel solver, the application context is shared by all the `DM` in the hierarchy; it is thus not advisable
    3837:   to store objects that represent discretized quantities inside the context.

    3839:   Fortran Notes:
    3840:   This only works when the context is a Fortran derived type or a `PetscObject`. Declare `ctx` with
    3841: .vb
    3842:   type(tUsertype), pointer :: ctx
    3843: .ve

    3845: .seealso: [](ch_dmbase), `DM`, `DMGetApplicationContext()`, `DMView()`, `DMCreateGlobalVector()`, `DMCreateInterpolation()`, `DMCreateColoring()`, `DMCreateMatrix()`, `DMCreateMassMatrix()`
    3846: @*/
    3847: PetscErrorCode DMSetApplicationContext(DM dm, PetscCtx ctx)
    3848: {
    3849:   PetscFunctionBegin;
    3851:   dm->ctx = ctx;
    3852:   PetscFunctionReturn(PETSC_SUCCESS);
    3853: }

    3855: /*@
    3856:   DMGetApplicationContext - Gets an application context from a `DM` object provided with `DMSetApplicationContext()`

    3858:   Not Collective

    3860:   Input Parameter:
    3861: . dm - the `DM` object

    3863:   Output Parameter:
    3864: . ctx - a pointer to the application context

    3866:   Level: intermediate

    3868:   Note:
    3869:   An application context is a way to pass problem specific information that is accessible whenever the `DM` is available

    3871:   Fortran Notes:
    3872:   This only works when the context is a Fortran derived type (it cannot be a `PetscObject`) and you **must** write a Fortran interface definition for this
    3873:   function that tells the Fortran compiler the derived data type that is returned as the `ctx` argument. For example,
    3874: .vb
    3875:   Interface DMGetApplicationContext
    3876:     Subroutine DMGetApplicationContext(dm,ctx,ierr)
    3877:   #include <petsc/finclude/petscdm.h>
    3878:       use petscdm
    3879:       DM dm
    3880:       type(tUsertype), pointer :: ctx
    3881:       PetscErrorCode ierr
    3882:     End Subroutine
    3883:   End Interface DMGetApplicationContext
    3884: .ve

    3886:   The prototype for `ctx` must be
    3887: .vb
    3888:   type(tUsertype), pointer :: ctx
    3889: .ve

    3891: .seealso: [](ch_dmbase), `DM`, `DMView()`, `DMCreateGlobalVector()`, `DMCreateInterpolation()`, `DMCreateColoring()`, `DMCreateMatrix()`, `DMCreateMassMatrix()`
    3892: @*/
    3893: PetscErrorCode DMGetApplicationContext(DM dm, PetscCtxRt ctx)
    3894: {
    3895:   PetscFunctionBegin;
    3897:   *(void **)ctx = dm->ctx;
    3898:   PetscFunctionReturn(PETSC_SUCCESS);
    3899: }

    3901: /*@C
    3902:   DMSetVariableBounds - sets a function to compute the lower and upper bound vectors for `SNESVI`.

    3904:   Logically Collective

    3906:   Input Parameters:
    3907: + dm - the `DM` object
    3908: - f  - the function that computes variable bounds used by `SNESVI` (use `NULL` to cancel a previous function that was set)

    3910:   Calling sequence of f:
    3911: + dm    - the `DM`
    3912: . lower - the vector to hold the lower bounds
    3913: - upper - the vector to hold the upper bounds

    3915:   Level: intermediate

    3917:   Developer Note:
    3918:   Should be called `DMSetComputeVIBounds()` or something similar

    3920: .seealso: [](ch_dmbase), `DM`, `DMComputeVariableBounds()`, `DMHasVariableBounds()`, `DMView()`, `DMCreateGlobalVector()`, `DMCreateInterpolation()`, `DMCreateColoring()`, `DMCreateMatrix()`, `DMCreateMassMatrix()`, `DMGetApplicationContext()`,
    3921:          `DMSetJacobian()`
    3922: @*/
    3923: PetscErrorCode DMSetVariableBounds(DM dm, PetscErrorCode (*f)(DM dm, Vec lower, Vec upper))
    3924: {
    3925:   PetscFunctionBegin;
    3927:   dm->ops->computevariablebounds = f;
    3928:   PetscFunctionReturn(PETSC_SUCCESS);
    3929: }

    3931: /*@
    3932:   DMHasVariableBounds - does the `DM` object have a variable bounds function?

    3934:   Not Collective

    3936:   Input Parameter:
    3937: . dm - the `DM` object to destroy

    3939:   Output Parameter:
    3940: . flg - `PETSC_TRUE` if the variable bounds function exists

    3942:   Level: developer

    3944: .seealso: [](ch_dmbase), `DM`, `DMComputeVariableBounds()`, `DMView()`, `DMCreateGlobalVector()`, `DMCreateInterpolation()`, `DMCreateColoring()`, `DMCreateMatrix()`, `DMCreateMassMatrix()`, `DMGetApplicationContext()`
    3945: @*/
    3946: PetscErrorCode DMHasVariableBounds(DM dm, PetscBool *flg)
    3947: {
    3948:   PetscFunctionBegin;
    3950:   PetscAssertPointer(flg, 2);
    3951:   *flg = (dm->ops->computevariablebounds) ? PETSC_TRUE : PETSC_FALSE;
    3952:   PetscFunctionReturn(PETSC_SUCCESS);
    3953: }

    3955: /*@
    3956:   DMComputeVariableBounds - compute variable bounds used by `SNESVI`.

    3958:   Logically Collective

    3960:   Input Parameter:
    3961: . dm - the `DM` object

    3963:   Output Parameters:
    3964: + xl - lower bound
    3965: - xu - upper bound

    3967:   Level: advanced

    3969:   Note:
    3970:   This is generally not called by users. It calls the function provided by the user with DMSetVariableBounds()

    3972: .seealso: [](ch_dmbase), `DM`, `DMHasVariableBounds()`, `DMView()`, `DMCreateGlobalVector()`, `DMCreateInterpolation()`, `DMCreateColoring()`, `DMCreateMatrix()`, `DMCreateMassMatrix()`, `DMGetApplicationContext()`
    3973: @*/
    3974: PetscErrorCode DMComputeVariableBounds(DM dm, Vec xl, Vec xu)
    3975: {
    3976:   PetscFunctionBegin;
    3980:   PetscUseTypeMethod(dm, computevariablebounds, xl, xu);
    3981:   PetscFunctionReturn(PETSC_SUCCESS);
    3982: }

    3984: /*@
    3985:   DMHasColoring - does the `DM` object have a method of providing a coloring?

    3987:   Not Collective

    3989:   Input Parameter:
    3990: . dm - the DM object

    3992:   Output Parameter:
    3993: . flg - `PETSC_TRUE` if the `DM` has facilities for `DMCreateColoring()`.

    3995:   Level: developer

    3997: .seealso: [](ch_dmbase), `DM`, `DMCreateColoring()`
    3998: @*/
    3999: PetscErrorCode DMHasColoring(DM dm, PetscBool *flg)
    4000: {
    4001:   PetscFunctionBegin;
    4003:   PetscAssertPointer(flg, 2);
    4004:   *flg = (dm->ops->getcoloring) ? PETSC_TRUE : PETSC_FALSE;
    4005:   PetscFunctionReturn(PETSC_SUCCESS);
    4006: }

    4008: /*@
    4009:   DMHasCreateRestriction - does the `DM` object have a method of providing a restriction?

    4011:   Not Collective

    4013:   Input Parameter:
    4014: . dm - the `DM` object

    4016:   Output Parameter:
    4017: . flg - `PETSC_TRUE` if the `DM` has facilities for `DMCreateRestriction()`.

    4019:   Level: developer

    4021: .seealso: [](ch_dmbase), `DM`, `DMCreateRestriction()`, `DMHasCreateInterpolation()`, `DMHasCreateInjection()`
    4022: @*/
    4023: PetscErrorCode DMHasCreateRestriction(DM dm, PetscBool *flg)
    4024: {
    4025:   PetscFunctionBegin;
    4027:   PetscAssertPointer(flg, 2);
    4028:   *flg = (dm->ops->createrestriction) ? PETSC_TRUE : PETSC_FALSE;
    4029:   PetscFunctionReturn(PETSC_SUCCESS);
    4030: }

    4032: /*@
    4033:   DMHasCreateInjection - does the `DM` object have a method of providing an injection?

    4035:   Not Collective

    4037:   Input Parameter:
    4038: . dm - the `DM` object

    4040:   Output Parameter:
    4041: . flg - `PETSC_TRUE` if the `DM` has facilities for `DMCreateInjection()`.

    4043:   Level: developer

    4045: .seealso: [](ch_dmbase), `DM`, `DMCreateInjection()`, `DMHasCreateRestriction()`, `DMHasCreateInterpolation()`
    4046: @*/
    4047: PetscErrorCode DMHasCreateInjection(DM dm, PetscBool *flg)
    4048: {
    4049:   PetscFunctionBegin;
    4051:   PetscAssertPointer(flg, 2);
    4052:   if (dm->ops->hascreateinjection) PetscUseTypeMethod(dm, hascreateinjection, flg);
    4053:   else *flg = (dm->ops->createinjection) ? PETSC_TRUE : PETSC_FALSE;
    4054:   PetscFunctionReturn(PETSC_SUCCESS);
    4055: }

    4057: PetscFunctionList DMList              = NULL;
    4058: PetscBool         DMRegisterAllCalled = PETSC_FALSE;

    4060: /*@
    4061:   DMSetType - Builds a `DM`, for a particular `DM` implementation.

    4063:   Collective

    4065:   Input Parameters:
    4066: + dm     - The `DM` object
    4067: - method - The name of the `DMType`, for example `DMDA`, `DMPLEX`

    4069:   Options Database Key:
    4070: . -dm_type type - Sets the `DM` type; use -help for a list of available types

    4072:   Level: intermediate

    4074:   Note:
    4075:   Of the `DM` is constructed by directly calling a function to construct a particular `DM`, for example, `DMDACreate2d()` or `DMPlexCreateBoxMesh()`

    4077: .seealso: [](ch_dmbase), `DM`, `DMType`, `DMDA`, `DMPLEX`, `DMGetType()`, `DMCreate()`, `DMDACreate2d()`
    4078: @*/
    4079: PetscErrorCode DMSetType(DM dm, DMType method)
    4080: {
    4081:   PetscErrorCode (*r)(DM);
    4082:   PetscBool match;

    4084:   PetscFunctionBegin;
    4086:   PetscCall(PetscObjectTypeCompare((PetscObject)dm, method, &match));
    4087:   if (match) PetscFunctionReturn(PETSC_SUCCESS);

    4089:   PetscCall(DMRegisterAll());
    4090:   PetscCall(PetscFunctionListFind(DMList, method, &r));
    4091:   PetscCheck(r, PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_UNKNOWN_TYPE, "Unknown DM type: %s", method);

    4093:   PetscTryTypeMethod(dm, destroy);
    4094:   PetscCall(PetscMemzero(dm->ops, sizeof(*dm->ops)));
    4095:   PetscCall(PetscObjectChangeTypeName((PetscObject)dm, method));
    4096:   PetscCall((*r)(dm));
    4097:   PetscFunctionReturn(PETSC_SUCCESS);
    4098: }

    4100: /*@
    4101:   DMGetType - Gets the `DM` type name (as a string) from the `DM`.

    4103:   Not Collective

    4105:   Input Parameter:
    4106: . dm - The `DM`

    4108:   Output Parameter:
    4109: . type - The `DMType` name

    4111:   Level: intermediate

    4113:   Note:
    4114:   `type` should not be retained for later use as it will be an invalid pointer if the `DMType` of `dm` is changed.

    4116: .seealso: [](ch_dmbase), `DM`, `DMType`, `DMDA`, `DMPLEX`, `DMSetType()`, `DMCreate()`, `PetscObjectTypeCompare()`, `PetscObjectTypeCompareAny()`
    4117: @*/
    4118: PetscErrorCode DMGetType(DM dm, DMType *type)
    4119: {
    4120:   PetscFunctionBegin;
    4122:   PetscAssertPointer(type, 2);
    4123:   PetscCall(DMRegisterAll());
    4124:   *type = ((PetscObject)dm)->type_name;
    4125:   PetscFunctionReturn(PETSC_SUCCESS);
    4126: }

    4128: /*@
    4129:   DMConvert - Converts a `DM` to another `DM`, either of the same or different type.

    4131:   Collective

    4133:   Input Parameters:
    4134: + dm      - the `DM`
    4135: - newtype - new `DM` type (use "same" for the same type)

    4137:   Output Parameter:
    4138: . M - pointer to new `DM`

    4140:   Level: intermediate

    4142:   Note:
    4143:   Cannot be used to convert a sequential `DM` to a parallel or a parallel to sequential,
    4144:   the MPI communicator of the generated `DM` is always the same as the communicator
    4145:   of the input `DM`.

    4147: .seealso: [](ch_dmbase), `DM`, `DMSetType()`, `DMCreate()`, `DMClone()`
    4148: @*/
    4149: PetscErrorCode DMConvert(DM dm, DMType newtype, DM *M)
    4150: {
    4151:   DM        B;
    4152:   char      convname[256];
    4153:   PetscBool sametype /*, issame */;

    4155:   PetscFunctionBegin;
    4158:   PetscAssertPointer(M, 3);
    4159:   PetscCall(PetscObjectTypeCompare((PetscObject)dm, newtype, &sametype));
    4160:   /* PetscCall(PetscStrcmp(newtype, "same", &issame)); */
    4161:   if (sametype) {
    4162:     *M = dm;
    4163:     PetscCall(PetscObjectReference((PetscObject)dm));
    4164:     PetscFunctionReturn(PETSC_SUCCESS);
    4165:   } else {
    4166:     PetscErrorCode (*conv)(DM, DMType, DM *) = NULL;

    4168:     /*
    4169:        Order of precedence:
    4170:        1) See if a specialized converter is known to the current DM.
    4171:        2) See if a specialized converter is known to the desired DM class.
    4172:        3) See if a good general converter is registered for the desired class
    4173:        4) See if a good general converter is known for the current matrix.
    4174:        5) Use a really basic converter.
    4175:     */

    4177:     /* 1) See if a specialized converter is known to the current DM and the desired class */
    4178:     PetscCall(PetscStrncpy(convname, "DMConvert_", sizeof(convname)));
    4179:     PetscCall(PetscStrlcat(convname, ((PetscObject)dm)->type_name, sizeof(convname)));
    4180:     PetscCall(PetscStrlcat(convname, "_", sizeof(convname)));
    4181:     PetscCall(PetscStrlcat(convname, newtype, sizeof(convname)));
    4182:     PetscCall(PetscStrlcat(convname, "_C", sizeof(convname)));
    4183:     PetscCall(PetscObjectQueryFunction((PetscObject)dm, convname, &conv));
    4184:     if (conv) goto foundconv;

    4186:     /* 2)  See if a specialized converter is known to the desired DM class. */
    4187:     PetscCall(DMCreate(PetscObjectComm((PetscObject)dm), &B));
    4188:     PetscCall(DMSetType(B, newtype));
    4189:     PetscCall(PetscStrncpy(convname, "DMConvert_", sizeof(convname)));
    4190:     PetscCall(PetscStrlcat(convname, ((PetscObject)dm)->type_name, sizeof(convname)));
    4191:     PetscCall(PetscStrlcat(convname, "_", sizeof(convname)));
    4192:     PetscCall(PetscStrlcat(convname, newtype, sizeof(convname)));
    4193:     PetscCall(PetscStrlcat(convname, "_C", sizeof(convname)));
    4194:     PetscCall(PetscObjectQueryFunction((PetscObject)B, convname, &conv));
    4195:     if (conv) {
    4196:       PetscCall(DMDestroy(&B));
    4197:       goto foundconv;
    4198:     }

    4200: #if 0
    4201:     /* 3) See if a good general converter is registered for the desired class */
    4202:     conv = B->ops->convertfrom;
    4203:     PetscCall(DMDestroy(&B));
    4204:     if (conv) goto foundconv;

    4206:     /* 4) See if a good general converter is known for the current matrix */
    4207:     if (dm->ops->convert) conv = dm->ops->convert;
    4208:     if (conv) goto foundconv;
    4209: #endif

    4211:     /* 5) Use a really basic converter. */
    4212:     SETERRQ(PetscObjectComm((PetscObject)dm), PETSC_ERR_SUP, "No conversion possible between DM types %s and %s", ((PetscObject)dm)->type_name, newtype);

    4214:   foundconv:
    4215:     PetscCall(PetscLogEventBegin(DM_Convert, dm, 0, 0, 0));
    4216:     PetscCall((*conv)(dm, newtype, M));
    4217:     /* Things that are independent of DM type: We should consult DMClone() here */
    4218:     {
    4219:       const PetscReal *maxCell, *Lstart, *L;

    4221:       PetscCall(DMGetPeriodicity(dm, &maxCell, &Lstart, &L));
    4222:       PetscCall(DMSetPeriodicity(*M, maxCell, Lstart, L));
    4223:       (*M)->prealloc_only = dm->prealloc_only;
    4224:       PetscCall(PetscFree((*M)->vectype));
    4225:       PetscCall(PetscStrallocpy(dm->vectype, (char **)&(*M)->vectype));
    4226:       PetscCall(PetscFree((*M)->mattype));
    4227:       PetscCall(PetscStrallocpy(dm->mattype, (char **)&(*M)->mattype));
    4228:     }
    4229:     PetscCall(PetscLogEventEnd(DM_Convert, dm, 0, 0, 0));
    4230:   }
    4231:   PetscCall(PetscObjectStateIncrease((PetscObject)*M));
    4232:   PetscFunctionReturn(PETSC_SUCCESS);
    4233: }

    4235: /*@C
    4236:   DMRegister -  Adds a new `DM` type implementation

    4238:   Not Collective, No Fortran Support

    4240:   Input Parameters:
    4241: + sname    - The name of a new user-defined creation routine
    4242: - function - The creation routine itself

    4244:   Calling sequence of function:
    4245: . dm - the new `DM` that is being created

    4247:   Level: advanced

    4249:   Note:
    4250:   `DMRegister()` may be called multiple times to add several user-defined `DM`s

    4252:   Example Usage:
    4253: .vb
    4254:     DMRegister("my_da", MyDMCreate);
    4255: .ve

    4257:   Then, your `DM` type can be chosen with the procedural interface via
    4258: .vb
    4259:     DMCreate(MPI_Comm, DM *);
    4260:     DMSetType(DM,"my_da");
    4261: .ve
    4262:   or at runtime via the option
    4263: .vb
    4264:     -da_type my_da
    4265: .ve

    4267: .seealso: [](ch_dmbase), `DM`, `DMType`, `DMSetType()`, `DMRegisterAll()`, `DMRegisterDestroy()`
    4268: @*/
    4269: PetscErrorCode DMRegister(const char sname[], PetscErrorCode (*function)(DM dm))
    4270: {
    4271:   PetscFunctionBegin;
    4272:   PetscCall(DMInitializePackage());
    4273:   PetscCall(PetscFunctionListAdd(&DMList, sname, function));
    4274:   PetscFunctionReturn(PETSC_SUCCESS);
    4275: }

    4277: /*@
    4278:   DMLoad - Loads a DM that has been stored in binary  with `DMView()`.

    4280:   Collective

    4282:   Input Parameters:
    4283: + newdm  - the newly loaded `DM`, this needs to have been created with `DMCreate()` or
    4284:            some related function before a call to `DMLoad()`.
    4285: - viewer - binary file viewer, obtained from `PetscViewerBinaryOpen()` or
    4286:            `PETSCVIEWERHDF5` file viewer, obtained from `PetscViewerHDF5Open()`

    4288:   Level: intermediate

    4290:   Notes:
    4291:   The type is determined by the data in the file, any type set into the DM before this call is ignored.

    4293:   Using `PETSCVIEWERHDF5` type with `PETSC_VIEWER_HDF5_PETSC` format, one can save multiple `DMPLEX`
    4294:   meshes in a single HDF5 file. This in turn requires one to name the `DMPLEX` object with `PetscObjectSetName()`
    4295:   before saving it with `DMView()` and before loading it with `DMLoad()` for identification of the mesh object.

    4297: .seealso: [](ch_dmbase), `DM`, `PetscViewerBinaryOpen()`, `DMView()`, `MatLoad()`, `VecLoad()`
    4298: @*/
    4299: PetscErrorCode DMLoad(DM newdm, PetscViewer viewer)
    4300: {
    4301:   PetscBool isbinary, ishdf5;

    4303:   PetscFunctionBegin;
    4306:   PetscCall(PetscViewerCheckReadable(viewer));
    4307:   PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERBINARY, &isbinary));
    4308:   PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERHDF5, &ishdf5));
    4309:   PetscCall(PetscLogEventBegin(DM_Load, viewer, 0, 0, 0));
    4310:   if (isbinary) {
    4311:     PetscInt classid;
    4312:     char     type[256];

    4314:     PetscCall(PetscViewerBinaryRead(viewer, &classid, 1, NULL, PETSC_INT));
    4315:     PetscCheck(classid == DM_FILE_CLASSID, PetscObjectComm((PetscObject)newdm), PETSC_ERR_ARG_WRONG, "Not DM next in file, classid found %" PetscInt_FMT, classid);
    4316:     PetscCall(PetscViewerBinaryRead(viewer, type, 256, NULL, PETSC_CHAR));
    4317:     PetscCall(DMSetType(newdm, type));
    4318:     PetscTryTypeMethod(newdm, load, viewer);
    4319:   } else if (ishdf5) {
    4320:     PetscTryTypeMethod(newdm, load, viewer);
    4321:   } else SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Invalid viewer; open viewer with PetscViewerBinaryOpen() or PetscViewerHDF5Open()");
    4322:   PetscCall(PetscLogEventEnd(DM_Load, viewer, 0, 0, 0));
    4323:   PetscFunctionReturn(PETSC_SUCCESS);
    4324: }

    4326: /* FEM Support */

    4328: /*@
    4329:   DMPrintCellIndices - Print an integer array of per-cell indices to `PETSC_COMM_SELF`

    4331:   Not Collective

    4333:   Input Parameters:
    4334: + c    - the cell number
    4335: . name - the label to print with the cell (typically the element or field name)
    4336: . len  - the length of `x`
    4337: - x    - the array of integer indices

    4339:   Level: developer

    4341: .seealso: [](ch_dmbase), `DM`, `DMPrintCellVector()`, `DMPrintCellVectorReal()`, `DMPrintCellMatrix()`, `DMPrintLocalVec()`
    4342: @*/
    4343: PetscErrorCode DMPrintCellIndices(PetscInt c, const char name[], PetscInt len, const PetscInt x[])
    4344: {
    4345:   PetscInt f;

    4347:   PetscFunctionBegin;
    4348:   PetscCall(PetscPrintf(PETSC_COMM_SELF, "Cell %" PetscInt_FMT " Element %s\n", c, name));
    4349:   for (f = 0; f < len; ++f) PetscCall(PetscPrintf(PETSC_COMM_SELF, "  | %" PetscInt_FMT " |\n", x[f]));
    4350:   PetscFunctionReturn(PETSC_SUCCESS);
    4351: }

    4353: /*@
    4354:   DMPrintCellVector - Print a scalar array representing a per-cell vector to `PETSC_COMM_SELF`

    4356:   Not Collective

    4358:   Input Parameters:
    4359: + c    - the cell number
    4360: . name - the label to print with the cell (typically the element or field name)
    4361: . len  - the length of `x`
    4362: - x    - the array of `PetscScalar` values

    4364:   Level: developer

    4366:   Note:
    4367:   Only the real part of each entry is printed.

    4369: .seealso: [](ch_dmbase), `DM`, `DMPrintCellIndices()`, `DMPrintCellVectorReal()`, `DMPrintCellMatrix()`, `DMPrintLocalVec()`
    4370: @*/
    4371: PetscErrorCode DMPrintCellVector(PetscInt c, const char name[], PetscInt len, const PetscScalar x[])
    4372: {
    4373:   PetscInt f;

    4375:   PetscFunctionBegin;
    4376:   PetscCall(PetscPrintf(PETSC_COMM_SELF, "Cell %" PetscInt_FMT " Element %s\n", c, name));
    4377:   for (f = 0; f < len; ++f) PetscCall(PetscPrintf(PETSC_COMM_SELF, "  | %g |\n", (double)PetscRealPart(x[f])));
    4378:   PetscFunctionReturn(PETSC_SUCCESS);
    4379: }

    4381: /*@
    4382:   DMPrintCellVectorReal - Print a real array representing a per-cell vector to `PETSC_COMM_SELF`

    4384:   Not Collective

    4386:   Input Parameters:
    4387: + c    - the cell number
    4388: . name - the label to print with the cell (typically the element or field name)
    4389: . len  - the length of `x`
    4390: - x    - the array of `PetscReal` values

    4392:   Level: developer

    4394: .seealso: [](ch_dmbase), `DM`, `DMPrintCellIndices()`, `DMPrintCellVector()`, `DMPrintCellMatrix()`, `DMPrintLocalVec()`
    4395: @*/
    4396: PetscErrorCode DMPrintCellVectorReal(PetscInt c, const char name[], PetscInt len, const PetscReal x[])
    4397: {
    4398:   PetscInt f;

    4400:   PetscFunctionBegin;
    4401:   PetscCall(PetscPrintf(PETSC_COMM_SELF, "Cell %" PetscInt_FMT " Element %s\n", c, name));
    4402:   for (f = 0; f < len; ++f) PetscCall(PetscPrintf(PETSC_COMM_SELF, "  | %g |\n", (double)x[f]));
    4403:   PetscFunctionReturn(PETSC_SUCCESS);
    4404: }

    4406: /*@
    4407:   DMPrintCellMatrix - Print a scalar array representing a per-cell matrix to `PETSC_COMM_SELF`

    4409:   Not Collective

    4411:   Input Parameters:
    4412: + c    - the cell number
    4413: . name - the label to print with the cell (typically the element or field name)
    4414: . rows - number of rows in the matrix
    4415: . cols - number of columns in the matrix
    4416: - A    - the row-major array of `PetscScalar` matrix entries

    4418:   Level: developer

    4420:   Note:
    4421:   Only the real part of each entry is printed.

    4423: .seealso: [](ch_dmbase), `DM`, `DMPrintCellIndices()`, `DMPrintCellVector()`, `DMPrintCellVectorReal()`, `DMPrintLocalVec()`
    4424: @*/
    4425: PetscErrorCode DMPrintCellMatrix(PetscInt c, const char name[], PetscInt rows, PetscInt cols, const PetscScalar A[])
    4426: {
    4427:   PetscInt f, g;

    4429:   PetscFunctionBegin;
    4430:   PetscCall(PetscPrintf(PETSC_COMM_SELF, "Cell %" PetscInt_FMT " Element %s\n", c, name));
    4431:   for (f = 0; f < rows; ++f) {
    4432:     PetscCall(PetscPrintf(PETSC_COMM_SELF, "  |"));
    4433:     for (g = 0; g < cols; ++g) PetscCall(PetscPrintf(PETSC_COMM_SELF, " % 9.5g", (double)PetscRealPart(A[f * cols + g])));
    4434:     PetscCall(PetscPrintf(PETSC_COMM_SELF, " |\n"));
    4435:   }
    4436:   PetscFunctionReturn(PETSC_SUCCESS);
    4437: }

    4439: /*@
    4440:   DMPrintLocalVec - Print a `Vec` associated with a `DM`, filtering out very small entries

    4442:   Collective

    4444:   Input Parameters:
    4445: + dm   - the `DM` providing the communicator
    4446: . name - a label printed before the vector values
    4447: . tol  - tolerance below which entries are filtered to zero using `VecFilter()`
    4448: - X    - the `Vec` to print

    4450:   Level: developer

    4452:   Note:
    4453:   Runs in parallel by wrapping the local portion of the vector in an MPI vector for viewing.

    4455: .seealso: [](ch_dmbase), `DM`, `DMPrintCellIndices()`, `DMPrintCellVector()`, `DMPrintCellVectorReal()`, `DMPrintCellMatrix()`, `VecFilter()`
    4456: @*/
    4457: PetscErrorCode DMPrintLocalVec(DM dm, const char name[], PetscReal tol, Vec X)
    4458: {
    4459:   PetscInt           localSize, bs;
    4460:   PetscMPIInt        size;
    4461:   Vec                x, xglob;
    4462:   const PetscScalar *xarray;

    4464:   PetscFunctionBegin;
    4465:   PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)dm), &size));
    4466:   PetscCall(VecDuplicate(X, &x));
    4467:   PetscCall(VecCopy(X, x));
    4468:   PetscCall(VecFilter(x, tol));
    4469:   PetscCall(PetscPrintf(PetscObjectComm((PetscObject)dm), "%s:\n", name));
    4470:   if (size > 1) {
    4471:     PetscCall(VecGetLocalSize(x, &localSize));
    4472:     PetscCall(VecGetArrayRead(x, &xarray));
    4473:     PetscCall(VecGetBlockSize(x, &bs));
    4474:     PetscCall(VecCreateMPIWithArray(PetscObjectComm((PetscObject)dm), bs, localSize, PETSC_DETERMINE, xarray, &xglob));
    4475:   } else {
    4476:     xglob = x;
    4477:   }
    4478:   PetscCall(VecView(xglob, PETSC_VIEWER_STDOUT_(PetscObjectComm((PetscObject)dm))));
    4479:   if (size > 1) {
    4480:     PetscCall(VecDestroy(&xglob));
    4481:     PetscCall(VecRestoreArrayRead(x, &xarray));
    4482:   }
    4483:   PetscCall(VecDestroy(&x));
    4484:   PetscFunctionReturn(PETSC_SUCCESS);
    4485: }

    4487: /*@
    4488:   DMGetLocalSection - Get the `PetscSection` encoding the local data layout for the `DM`.

    4490:   Input Parameter:
    4491: . dm - The `DM`

    4493:   Output Parameter:
    4494: . section - The `PetscSection`

    4496:   Options Database Key:
    4497: . -dm_petscsection_view - View the section created by the `DM`

    4499:   Level: intermediate

    4501:   Note:
    4502:   This gets a borrowed reference, so the user should not destroy this `PetscSection`.

    4504: .seealso: [](ch_dmbase), `DM`, `DMSetLocalSection()`, `DMGetGlobalSection()`
    4505: @*/
    4506: PetscErrorCode DMGetLocalSection(DM dm, PetscSection *section)
    4507: {
    4508:   PetscFunctionBegin;
    4510:   PetscAssertPointer(section, 2);
    4511:   if (!dm->localSection && dm->ops->createlocalsection) {
    4512:     PetscInt d;

    4514:     if (dm->setfromoptionscalled) {
    4515:       PetscObject       obj = (PetscObject)dm;
    4516:       PetscViewer       viewer;
    4517:       PetscViewerFormat format;
    4518:       PetscBool         flg;

    4520:       PetscCall(PetscOptionsCreateViewer(PetscObjectComm(obj), obj->options, obj->prefix, "-dm_petscds_view", &viewer, &format, &flg));
    4521:       if (flg) PetscCall(PetscViewerPushFormat(viewer, format));
    4522:       for (d = 0; d < dm->Nds; ++d) {
    4523:         PetscCall(PetscDSSetFromOptions(dm->probs[d].ds));
    4524:         if (flg) PetscCall(PetscDSView(dm->probs[d].ds, viewer));
    4525:       }
    4526:       if (flg) {
    4527:         PetscCall(PetscViewerFlush(viewer));
    4528:         PetscCall(PetscViewerPopFormat(viewer));
    4529:         PetscCall(PetscViewerDestroy(&viewer));
    4530:       }
    4531:     }
    4532:     PetscUseTypeMethod(dm, createlocalsection);
    4533:     if (dm->localSection) PetscCall(PetscObjectViewFromOptions((PetscObject)dm->localSection, NULL, "-dm_petscsection_view"));
    4534:   }
    4535:   *section = dm->localSection;
    4536:   PetscFunctionReturn(PETSC_SUCCESS);
    4537: }

    4539: /*@
    4540:   DMSetLocalSection - Set the `PetscSection` encoding the local data layout for the `DM`.

    4542:   Input Parameters:
    4543: + dm      - The `DM`
    4544: - section - The `PetscSection`

    4546:   Level: intermediate

    4548:   Note:
    4549:   Any existing Section will be destroyed

    4551: .seealso: [](ch_dmbase), `DM`, `PetscSection`, `DMGetLocalSection()`, `DMSetGlobalSection()`
    4552: @*/
    4553: PetscErrorCode DMSetLocalSection(DM dm, PetscSection section)
    4554: {
    4555:   PetscInt numFields = 0;
    4556:   PetscInt f;

    4558:   PetscFunctionBegin;
    4561:   PetscCall(PetscObjectReference((PetscObject)section));
    4562:   PetscCall(PetscSectionDestroy(&dm->localSection));
    4563:   dm->localSection = section;
    4564:   if (section) PetscCall(PetscSectionGetNumFields(dm->localSection, &numFields));
    4565:   if (numFields) {
    4566:     PetscCall(DMSetNumFields(dm, numFields));
    4567:     for (f = 0; f < numFields; ++f) {
    4568:       PetscObject disc;
    4569:       const char *name;

    4571:       PetscCall(PetscSectionGetFieldName(dm->localSection, f, &name));
    4572:       PetscCall(DMGetField(dm, f, NULL, &disc));
    4573:       PetscCall(PetscObjectSetName(disc, name));
    4574:     }
    4575:   }
    4576:   /* The global section and the SectionSF will be rebuilt
    4577:      in the next call to DMGetGlobalSection() and DMGetSectionSF(). */
    4578:   PetscCall(PetscSectionDestroy(&dm->globalSection));
    4579:   PetscCall(PetscSFDestroy(&dm->sectionSF));
    4580:   PetscCall(PetscSFCreate(PetscObjectComm((PetscObject)dm), &dm->sectionSF));

    4582:   /* Clear scratch vectors */
    4583:   PetscCall(DMClearGlobalVectors(dm));
    4584:   PetscCall(DMClearLocalVectors(dm));
    4585:   PetscCall(DMClearNamedGlobalVectors(dm));
    4586:   PetscCall(DMClearNamedLocalVectors(dm));
    4587:   PetscFunctionReturn(PETSC_SUCCESS);
    4588: }

    4590: /*@C
    4591:   DMCreateSectionPermutation - Create a permutation of the `PetscSection` chart and optionally a block structure.

    4593:   Input Parameter:
    4594: . dm - The `DM`

    4596:   Output Parameters:
    4597: + perm        - A permutation of the mesh points in the chart
    4598: - blockStarts - A high bit is set for the point that begins every block, or `NULL` for default blocking

    4600:   Level: developer

    4602: .seealso: [](ch_dmbase), `DM`, `PetscSection`, `DMGetLocalSection()`, `DMGetGlobalSection()`
    4603: @*/
    4604: PetscErrorCode DMCreateSectionPermutation(DM dm, IS *perm, PetscBT *blockStarts)
    4605: {
    4606:   PetscFunctionBegin;
    4607:   *perm        = NULL;
    4608:   *blockStarts = NULL;
    4609:   PetscTryTypeMethod(dm, createsectionpermutation, perm, blockStarts);
    4610:   PetscFunctionReturn(PETSC_SUCCESS);
    4611: }

    4613: /*@
    4614:   DMGetDefaultConstraints - Get the `PetscSection` and `Mat` that specify the local constraint interpolation. See `DMSetDefaultConstraints()` for a description of the purpose of constraint interpolation.

    4616:   not Collective

    4618:   Input Parameter:
    4619: . dm - The `DM`

    4621:   Output Parameters:
    4622: + section - The `PetscSection` describing the range of the constraint matrix: relates rows of the constraint matrix to dofs of the default section.  Returns `NULL` if there are no local constraints.
    4623: . mat     - The `Mat` that interpolates local constraints: its width should be the layout size of the default section.  Returns `NULL` if there are no local constraints.
    4624: - bias    - Vector containing bias to be added to constrained dofs

    4626:   Level: advanced

    4628:   Note:
    4629:   This gets borrowed references, so the user should not destroy the `PetscSection`, `Mat`, or `Vec`.

    4631: .seealso: [](ch_dmbase), `DM`, `DMSetDefaultConstraints()`
    4632: @*/
    4633: PetscErrorCode DMGetDefaultConstraints(DM dm, PetscSection *section, Mat *mat, Vec *bias)
    4634: {
    4635:   PetscFunctionBegin;
    4637:   if (!dm->defaultConstraint.section && !dm->defaultConstraint.mat && dm->ops->createdefaultconstraints) PetscUseTypeMethod(dm, createdefaultconstraints);
    4638:   if (section) *section = dm->defaultConstraint.section;
    4639:   if (mat) *mat = dm->defaultConstraint.mat;
    4640:   if (bias) *bias = dm->defaultConstraint.bias;
    4641:   PetscFunctionReturn(PETSC_SUCCESS);
    4642: }

    4644: /*@
    4645:   DMSetDefaultConstraints - Set the `PetscSection` and `Mat` that specify the local constraint interpolation.

    4647:   Collective

    4649:   Input Parameters:
    4650: + dm      - The `DM`
    4651: . section - The `PetscSection` describing the range of the constraint matrix: relates rows of the constraint matrix to dofs of the default section.  Must have a local communicator (`PETSC_COMM_SELF` or derivative).
    4652: . mat     - The `Mat` that interpolates local constraints: its width should be the layout size of the default section:  `NULL` indicates no constraints.  Must have a local communicator (`PETSC_COMM_SELF` or derivative).
    4653: - bias    - A bias vector to be added to constrained values in the local vector.  `NULL` indicates no bias.  Must have a local communicator (`PETSC_COMM_SELF` or derivative).

    4655:   Level: advanced

    4657:   Notes:
    4658:   If a constraint matrix is specified, then it is applied during `DMGlobalToLocalEnd()` when mode is `INSERT_VALUES`, `INSERT_BC_VALUES`, or `INSERT_ALL_VALUES`.  Without a constraint matrix, the local vector l returned by `DMGlobalToLocalEnd()` contains values that have been scattered from a global vector without modification; with a constraint matrix A, l is modified by computing c = A * l + bias, l[s[i]] = c[i], where the scatter s is defined by the `PetscSection` returned by `DMGetDefaultConstraints()`.

    4660:   If a constraint matrix is specified, then its adjoint is applied during `DMLocalToGlobalBegin()` when mode is `ADD_VALUES`, `ADD_BC_VALUES`, or `ADD_ALL_VALUES`.  Without a constraint matrix, the local vector l is accumulated into a global vector without modification; with a constraint matrix A, l is first modified by computing c[i] = l[s[i]], l[s[i]] = 0, l = l + A'*c, which is the adjoint of the operation described above.  Any bias, if specified, is ignored when accumulating.

    4662:   This increments the references of the `PetscSection`, `Mat`, and `Vec`, so they user can destroy them.

    4664: .seealso: [](ch_dmbase), `DM`, `DMGetDefaultConstraints()`
    4665: @*/
    4666: PetscErrorCode DMSetDefaultConstraints(DM dm, PetscSection section, Mat mat, Vec bias)
    4667: {
    4668:   PetscMPIInt result;

    4670:   PetscFunctionBegin;
    4672:   if (section) {
    4674:     PetscCallMPI(MPI_Comm_compare(PETSC_COMM_SELF, PetscObjectComm((PetscObject)section), &result));
    4675:     PetscCheck(result == MPI_CONGRUENT || result == MPI_IDENT, PETSC_COMM_SELF, PETSC_ERR_ARG_NOTSAMECOMM, "constraint section must have local communicator");
    4676:   }
    4677:   if (mat) {
    4679:     PetscCallMPI(MPI_Comm_compare(PETSC_COMM_SELF, PetscObjectComm((PetscObject)mat), &result));
    4680:     PetscCheck(result == MPI_CONGRUENT || result == MPI_IDENT, PETSC_COMM_SELF, PETSC_ERR_ARG_NOTSAMECOMM, "constraint matrix must have local communicator");
    4681:   }
    4682:   if (bias) {
    4684:     PetscCallMPI(MPI_Comm_compare(PETSC_COMM_SELF, PetscObjectComm((PetscObject)bias), &result));
    4685:     PetscCheck(result == MPI_CONGRUENT || result == MPI_IDENT, PETSC_COMM_SELF, PETSC_ERR_ARG_NOTSAMECOMM, "constraint bias must have local communicator");
    4686:   }
    4687:   PetscCall(PetscObjectReference((PetscObject)section));
    4688:   PetscCall(PetscSectionDestroy(&dm->defaultConstraint.section));
    4689:   dm->defaultConstraint.section = section;
    4690:   PetscCall(PetscObjectReference((PetscObject)mat));
    4691:   PetscCall(MatDestroy(&dm->defaultConstraint.mat));
    4692:   dm->defaultConstraint.mat = mat;
    4693:   PetscCall(PetscObjectReference((PetscObject)bias));
    4694:   PetscCall(VecDestroy(&dm->defaultConstraint.bias));
    4695:   dm->defaultConstraint.bias = bias;
    4696:   PetscFunctionReturn(PETSC_SUCCESS);
    4697: }

    4699: #if defined(PETSC_USE_DEBUG)
    4700: /*
    4701:   DMDefaultSectionCheckConsistency - Check the consistentcy of the global and local sections. Generates and error if they are not consistent.

    4703:   Input Parameters:
    4704: + dm - The `DM`
    4705: . localSection - `PetscSection` describing the local data layout
    4706: - globalSection - `PetscSection` describing the global data layout

    4708:   Level: intermediate

    4710: .seealso: [](ch_dmbase), `DM`, `DMGetSectionSF()`, `DMSetSectionSF()`
    4711: */
    4712: static PetscErrorCode DMDefaultSectionCheckConsistency_Internal(DM dm, PetscSection localSection, PetscSection globalSection)
    4713: {
    4714:   MPI_Comm        comm;
    4715:   PetscLayout     layout;
    4716:   const PetscInt *ranges;
    4717:   PetscInt        pStart, pEnd, p, nroots;
    4718:   PetscMPIInt     size, rank;
    4719:   PetscBool       valid = PETSC_TRUE, gvalid;

    4721:   PetscFunctionBegin;
    4722:   PetscCall(PetscObjectGetComm((PetscObject)dm, &comm));
    4724:   PetscCallMPI(MPI_Comm_size(comm, &size));
    4725:   PetscCallMPI(MPI_Comm_rank(comm, &rank));
    4726:   PetscCall(PetscSectionGetChart(globalSection, &pStart, &pEnd));
    4727:   PetscCall(PetscSectionGetConstrainedStorageSize(globalSection, &nroots));
    4728:   PetscCall(PetscLayoutCreate(comm, &layout));
    4729:   PetscCall(PetscLayoutSetBlockSize(layout, 1));
    4730:   PetscCall(PetscLayoutSetLocalSize(layout, nroots));
    4731:   PetscCall(PetscLayoutSetUp(layout));
    4732:   PetscCall(PetscLayoutGetRanges(layout, &ranges));
    4733:   for (p = pStart; p < pEnd; ++p) {
    4734:     PetscInt dof, cdof, off, gdof, gcdof, goff, gsize, d;

    4736:     PetscCall(PetscSectionGetDof(localSection, p, &dof));
    4737:     PetscCall(PetscSectionGetOffset(localSection, p, &off));
    4738:     PetscCall(PetscSectionGetConstraintDof(localSection, p, &cdof));
    4739:     PetscCall(PetscSectionGetDof(globalSection, p, &gdof));
    4740:     PetscCall(PetscSectionGetConstraintDof(globalSection, p, &gcdof));
    4741:     PetscCall(PetscSectionGetOffset(globalSection, p, &goff));
    4742:     if (!gdof) continue; /* Censored point */
    4743:     if ((gdof < 0 ? -(gdof + 1) : gdof) != dof) {
    4744:       PetscCall(PetscSynchronizedPrintf(comm, "[%d]Global dof %" PetscInt_FMT " for point %" PetscInt_FMT " not equal to local dof %" PetscInt_FMT "\n", rank, gdof, p, dof));
    4745:       valid = PETSC_FALSE;
    4746:     }
    4747:     if (gcdof && (gcdof != cdof)) {
    4748:       PetscCall(PetscSynchronizedPrintf(comm, "[%d]Global constraints %" PetscInt_FMT " for point %" PetscInt_FMT " not equal to local constraints %" PetscInt_FMT "\n", rank, gcdof, p, cdof));
    4749:       valid = PETSC_FALSE;
    4750:     }
    4751:     if (gdof < 0) {
    4752:       gsize = gdof < 0 ? -(gdof + 1) - gcdof : gdof - gcdof;
    4753:       for (d = 0; d < gsize; ++d) {
    4754:         PetscInt offset = -(goff + 1) + d, r;

    4756:         PetscCall(PetscFindInt(offset, size + 1, ranges, &r));
    4757:         if (r < 0) r = -(r + 2);
    4758:         if ((r < 0) || (r >= size)) {
    4759:           PetscCall(PetscSynchronizedPrintf(comm, "[%d]Point %" PetscInt_FMT " mapped to invalid process %" PetscInt_FMT " (%" PetscInt_FMT ", %" PetscInt_FMT ")\n", rank, p, r, gdof, goff));
    4760:           valid = PETSC_FALSE;
    4761:           break;
    4762:         }
    4763:       }
    4764:     }
    4765:   }
    4766:   PetscCall(PetscLayoutDestroy(&layout));
    4767:   PetscCall(PetscSynchronizedFlush(comm, NULL));
    4768:   PetscCallMPI(MPIU_Allreduce(&valid, &gvalid, 1, MPI_C_BOOL, MPI_LAND, comm));
    4769:   if (!gvalid) {
    4770:     PetscCall(DMView(dm, NULL));
    4771:     SETERRQ(comm, PETSC_ERR_ARG_WRONG, "Inconsistent local and global sections");
    4772:   }
    4773:   PetscFunctionReturn(PETSC_SUCCESS);
    4774: }
    4775: #endif

    4777: PetscErrorCode DMGetIsoperiodicPointSF_Internal(DM dm, PetscSF *sf)
    4778: {
    4779:   PetscErrorCode (*f)(DM, PetscSF *);

    4781:   PetscFunctionBegin;
    4783:   PetscAssertPointer(sf, 2);
    4784:   PetscCall(PetscObjectQueryFunction((PetscObject)dm, "DMGetIsoperiodicPointSF_C", &f));
    4785:   if (f) PetscCall(f(dm, sf));
    4786:   else *sf = dm->sf;
    4787:   PetscFunctionReturn(PETSC_SUCCESS);
    4788: }

    4790: /*@
    4791:   DMGetGlobalSection - Get the `PetscSection` encoding the global data layout for the `DM`.

    4793:   Collective

    4795:   Input Parameter:
    4796: . dm - The `DM`

    4798:   Output Parameter:
    4799: . section - The `PetscSection`

    4801:   Level: intermediate

    4803:   Note:
    4804:   This gets a borrowed reference, so the user should not destroy this `PetscSection`.

    4806: .seealso: [](ch_dmbase), `DM`, `DMSetLocalSection()`, `DMGetLocalSection()`
    4807: @*/
    4808: PetscErrorCode DMGetGlobalSection(DM dm, PetscSection *section)
    4809: {
    4810:   PetscFunctionBegin;
    4812:   PetscAssertPointer(section, 2);
    4813:   if (!dm->globalSection) {
    4814:     PetscSection s;
    4815:     PetscSF      sf;

    4817:     PetscCall(DMGetLocalSection(dm, &s));
    4818:     PetscCheck(s, PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_WRONGSTATE, "DM must have a default PetscSection in order to create a global PetscSection");
    4819:     PetscCheck(dm->sf, PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_WRONGSTATE, "DM must have a point PetscSF in order to create a global PetscSection");
    4820:     PetscCall(DMGetIsoperiodicPointSF_Internal(dm, &sf));
    4821:     PetscCall(PetscSectionCreateGlobalSection(s, sf, PETSC_TRUE, PETSC_FALSE, PETSC_FALSE, &dm->globalSection));
    4822:     PetscCall(PetscLayoutDestroy(&dm->map));
    4823:     PetscCall(PetscSectionGetValueLayout(PetscObjectComm((PetscObject)dm), dm->globalSection, &dm->map));
    4824:     PetscCall(PetscSectionViewFromOptions(dm->globalSection, NULL, "-global_section_view"));
    4825:   }
    4826:   *section = dm->globalSection;
    4827:   PetscFunctionReturn(PETSC_SUCCESS);
    4828: }

    4830: /*@
    4831:   DMSetGlobalSection - Set the `PetscSection` encoding the global data layout for the `DM`.

    4833:   Input Parameters:
    4834: + dm      - The `DM`
    4835: - section - The PetscSection, or `NULL`

    4837:   Level: intermediate

    4839:   Note:
    4840:   Any existing `PetscSection` will be destroyed

    4842: .seealso: [](ch_dmbase), `DM`, `DMGetGlobalSection()`, `DMSetLocalSection()`
    4843: @*/
    4844: PetscErrorCode DMSetGlobalSection(DM dm, PetscSection section)
    4845: {
    4846:   PetscFunctionBegin;
    4849:   PetscCall(PetscObjectReference((PetscObject)section));
    4850:   PetscCall(PetscSectionDestroy(&dm->globalSection));
    4851:   dm->globalSection = section;
    4852: #if defined(PETSC_USE_DEBUG)
    4853:   if (section) PetscCall(DMDefaultSectionCheckConsistency_Internal(dm, dm->localSection, section));
    4854: #endif
    4855:   /* Clear global scratch vectors and sectionSF */
    4856:   PetscCall(PetscSFDestroy(&dm->sectionSF));
    4857:   PetscCall(PetscSFCreate(PetscObjectComm((PetscObject)dm), &dm->sectionSF));
    4858:   PetscCall(DMClearGlobalVectors(dm));
    4859:   PetscCall(DMClearNamedGlobalVectors(dm));
    4860:   PetscFunctionReturn(PETSC_SUCCESS);
    4861: }

    4863: /*@
    4864:   DMGetSectionSF - Get the `PetscSF` encoding the parallel dof overlap for the `DM`. If it has not been set,
    4865:   it is created from the default `PetscSection` layouts in the `DM`.

    4867:   Input Parameter:
    4868: . dm - The `DM`

    4870:   Output Parameter:
    4871: . sf - The `PetscSF`

    4873:   Level: intermediate

    4875:   Note:
    4876:   This gets a borrowed reference, so the user should not destroy this `PetscSF`.

    4878: .seealso: [](ch_dmbase), `DM`, `DMSetSectionSF()`, `DMCreateSectionSF()`
    4879: @*/
    4880: PetscErrorCode DMGetSectionSF(DM dm, PetscSF *sf)
    4881: {
    4882:   PetscInt nroots;

    4884:   PetscFunctionBegin;
    4886:   PetscAssertPointer(sf, 2);
    4887:   if (!dm->sectionSF) PetscCall(PetscSFCreate(PetscObjectComm((PetscObject)dm), &dm->sectionSF));
    4888:   PetscCall(PetscSFGetGraph(dm->sectionSF, &nroots, NULL, NULL, NULL));
    4889:   if (nroots < 0) {
    4890:     PetscSection section, gSection;

    4892:     PetscCall(DMGetLocalSection(dm, &section));
    4893:     if (section) {
    4894:       PetscCall(DMGetGlobalSection(dm, &gSection));
    4895:       PetscCall(DMCreateSectionSF(dm, section, gSection));
    4896:     } else {
    4897:       *sf = NULL;
    4898:       PetscFunctionReturn(PETSC_SUCCESS);
    4899:     }
    4900:   }
    4901:   *sf = dm->sectionSF;
    4902:   PetscFunctionReturn(PETSC_SUCCESS);
    4903: }

    4905: /*@
    4906:   DMSetSectionSF - Set the `PetscSF` encoding the parallel dof overlap for the `DM`

    4908:   Input Parameters:
    4909: + dm - The `DM`
    4910: - sf - The `PetscSF`

    4912:   Level: intermediate

    4914:   Note:
    4915:   Any previous `PetscSF` is destroyed

    4917: .seealso: [](ch_dmbase), `DM`, `DMGetSectionSF()`, `DMCreateSectionSF()`
    4918: @*/
    4919: PetscErrorCode DMSetSectionSF(DM dm, PetscSF sf)
    4920: {
    4921:   PetscFunctionBegin;
    4924:   PetscCall(PetscObjectReference((PetscObject)sf));
    4925:   PetscCall(PetscSFDestroy(&dm->sectionSF));
    4926:   dm->sectionSF = sf;
    4927:   PetscFunctionReturn(PETSC_SUCCESS);
    4928: }

    4930: /*@
    4931:   DMCreateSectionSF - Create the `PetscSF` encoding the parallel dof overlap for the `DM` based upon the `PetscSection`s
    4932:   describing the data layout.

    4934:   Input Parameters:
    4935: + dm            - The `DM`
    4936: . localSection  - `PetscSection` describing the local data layout
    4937: - globalSection - `PetscSection` describing the global data layout

    4939:   Level: developer

    4941:   Note:
    4942:   One usually uses `DMGetSectionSF()` to obtain the `PetscSF`

    4944:   Developer Note:
    4945:   Since this routine has for arguments the two sections from the `DM` and puts the resulting `PetscSF`
    4946:   directly into the `DM`, perhaps this function should not take the local and global sections as
    4947:   input and should just obtain them from the `DM`? Plus PETSc creation functions return the thing
    4948:   they create, this returns nothing

    4950: .seealso: [](ch_dmbase), `DM`, `DMGetSectionSF()`, `DMSetSectionSF()`, `DMGetLocalSection()`, `DMGetGlobalSection()`
    4951: @*/
    4952: PetscErrorCode DMCreateSectionSF(DM dm, PetscSection localSection, PetscSection globalSection)
    4953: {
    4954:   PetscFunctionBegin;
    4956:   PetscCall(PetscSFSetGraphSection(dm->sectionSF, localSection, globalSection));
    4957:   PetscFunctionReturn(PETSC_SUCCESS);
    4958: }

    4960: /*@
    4961:   DMGetPointSF - Get the `PetscSF` encoding the parallel section point overlap for the `DM`.

    4963:   Not collective but the resulting `PetscSF` is collective

    4965:   Input Parameter:
    4966: . dm - The `DM`

    4968:   Output Parameter:
    4969: . sf - The `PetscSF`

    4971:   Level: intermediate

    4973:   Note:
    4974:   This gets a borrowed reference, so the user should not destroy this `PetscSF`.

    4976: .seealso: [](ch_dmbase), `DM`, `DMSetPointSF()`, `DMGetSectionSF()`, `DMSetSectionSF()`, `DMCreateSectionSF()`
    4977: @*/
    4978: PetscErrorCode DMGetPointSF(DM dm, PetscSF *sf)
    4979: {
    4980:   PetscFunctionBegin;
    4982:   PetscAssertPointer(sf, 2);
    4983:   *sf = dm->sf;
    4984:   PetscFunctionReturn(PETSC_SUCCESS);
    4985: }

    4987: /*@
    4988:   DMSetPointSF - Set the `PetscSF` encoding the parallel section point overlap for the `DM`.

    4990:   Collective

    4992:   Input Parameters:
    4993: + dm - The `DM`
    4994: - sf - The `PetscSF`

    4996:   Level: intermediate

    4998: .seealso: [](ch_dmbase), `DM`, `DMGetPointSF()`, `DMGetSectionSF()`, `DMSetSectionSF()`, `DMCreateSectionSF()`
    4999: @*/
    5000: PetscErrorCode DMSetPointSF(DM dm, PetscSF sf)
    5001: {
    5002:   PetscFunctionBegin;
    5005:   PetscCall(PetscObjectReference((PetscObject)sf));
    5006:   PetscCall(PetscSFDestroy(&dm->sf));
    5007:   dm->sf = sf;
    5008:   PetscFunctionReturn(PETSC_SUCCESS);
    5009: }

    5011: /*@
    5012:   DMGetNaturalSF - Get the `PetscSF` encoding the map back to the original mesh ordering

    5014:   Input Parameter:
    5015: . dm - The `DM`

    5017:   Output Parameter:
    5018: . sf - The `PetscSF`

    5020:   Level: intermediate

    5022:   Note:
    5023:   This gets a borrowed reference, so the user should not destroy this `PetscSF`.

    5025: .seealso: [](ch_dmbase), `DM`, `DMSetNaturalSF()`, `DMSetUseNatural()`, `DMGetUseNatural()`, `DMPlexCreateGlobalToNaturalSF()`, `DMPlexDistribute()`
    5026: @*/
    5027: PetscErrorCode DMGetNaturalSF(DM dm, PetscSF *sf)
    5028: {
    5029:   PetscFunctionBegin;
    5031:   PetscAssertPointer(sf, 2);
    5032:   *sf = dm->sfNatural;
    5033:   PetscFunctionReturn(PETSC_SUCCESS);
    5034: }

    5036: /*@
    5037:   DMSetNaturalSF - Set the PetscSF encoding the map back to the original mesh ordering

    5039:   Input Parameters:
    5040: + dm - The DM
    5041: - sf - The PetscSF

    5043:   Level: intermediate

    5045: .seealso: [](ch_dmbase), `DM`, `DMGetNaturalSF()`, `DMSetUseNatural()`, `DMGetUseNatural()`, `DMPlexCreateGlobalToNaturalSF()`, `DMPlexDistribute()`
    5046: @*/
    5047: PetscErrorCode DMSetNaturalSF(DM dm, PetscSF sf)
    5048: {
    5049:   PetscFunctionBegin;
    5052:   PetscCall(PetscObjectReference((PetscObject)sf));
    5053:   PetscCall(PetscSFDestroy(&dm->sfNatural));
    5054:   dm->sfNatural = sf;
    5055:   PetscFunctionReturn(PETSC_SUCCESS);
    5056: }

    5058: static PetscErrorCode DMSetDefaultAdjacency_Private(DM dm, PetscInt f, PetscObject disc)
    5059: {
    5060:   PetscClassId id;

    5062:   PetscFunctionBegin;
    5063:   PetscCall(PetscObjectGetClassId(disc, &id));
    5064:   if (id == PETSCFE_CLASSID) PetscCall(DMSetAdjacency(dm, f, PETSC_FALSE, PETSC_TRUE));
    5065:   else if (id == PETSCFV_CLASSID) PetscCall(DMSetAdjacency(dm, f, PETSC_TRUE, PETSC_FALSE));
    5066:   else PetscCall(DMSetAdjacency(dm, f, PETSC_FALSE, PETSC_TRUE));
    5067:   PetscFunctionReturn(PETSC_SUCCESS);
    5068: }

    5070: static PetscErrorCode DMFieldEnlarge_Static(DM dm, PetscInt NfNew)
    5071: {
    5072:   RegionField *tmpr;
    5073:   PetscInt     Nf = dm->Nf, f;

    5075:   PetscFunctionBegin;
    5076:   if (Nf >= NfNew) PetscFunctionReturn(PETSC_SUCCESS);
    5077:   PetscCall(PetscMalloc1(NfNew, &tmpr));
    5078:   for (f = 0; f < Nf; ++f) tmpr[f] = dm->fields[f];
    5079:   for (f = Nf; f < NfNew; ++f) {
    5080:     tmpr[f].disc        = NULL;
    5081:     tmpr[f].label       = NULL;
    5082:     tmpr[f].avoidTensor = PETSC_FALSE;
    5083:   }
    5084:   PetscCall(PetscFree(dm->fields));
    5085:   dm->Nf     = NfNew;
    5086:   dm->fields = tmpr;
    5087:   PetscFunctionReturn(PETSC_SUCCESS);
    5088: }

    5090: /*@
    5091:   DMClearFields - Remove all fields from the `DM`

    5093:   Logically Collective

    5095:   Input Parameter:
    5096: . dm - The `DM`

    5098:   Level: intermediate

    5100: .seealso: [](ch_dmbase), `DM`, `DMGetNumFields()`, `DMSetNumFields()`, `DMSetField()`
    5101: @*/
    5102: PetscErrorCode DMClearFields(DM dm)
    5103: {
    5104:   PetscInt f;

    5106:   PetscFunctionBegin;
    5108:   if (!dm->fields) PetscFunctionReturn(PETSC_SUCCESS); // DMDA does not use fields field in DM
    5109:   for (f = 0; f < dm->Nf; ++f) {
    5110:     PetscCall(PetscObjectDestroy(&dm->fields[f].disc));
    5111:     PetscCall(DMLabelDestroy(&dm->fields[f].label));
    5112:   }
    5113:   PetscCall(PetscFree(dm->fields));
    5114:   dm->fields = NULL;
    5115:   dm->Nf     = 0;
    5116:   PetscFunctionReturn(PETSC_SUCCESS);
    5117: }

    5119: /*@
    5120:   DMGetNumFields - Get the number of fields in the `DM`

    5122:   Not Collective

    5124:   Input Parameter:
    5125: . dm - The `DM`

    5127:   Output Parameter:
    5128: . numFields - The number of fields

    5130:   Level: intermediate

    5132: .seealso: [](ch_dmbase), `DM`, `DMSetNumFields()`, `DMSetField()`
    5133: @*/
    5134: PetscErrorCode DMGetNumFields(DM dm, PetscInt *numFields)
    5135: {
    5136:   PetscFunctionBegin;
    5138:   PetscAssertPointer(numFields, 2);
    5139:   *numFields = dm->Nf;
    5140:   PetscFunctionReturn(PETSC_SUCCESS);
    5141: }

    5143: /*@
    5144:   DMSetNumFields - Set the number of fields in the `DM`

    5146:   Logically Collective

    5148:   Input Parameters:
    5149: + dm        - The `DM`
    5150: - numFields - The number of fields

    5152:   Level: intermediate

    5154: .seealso: [](ch_dmbase), `DM`, `DMGetNumFields()`, `DMSetField()`
    5155: @*/
    5156: PetscErrorCode DMSetNumFields(DM dm, PetscInt numFields)
    5157: {
    5158:   PetscInt Nf, f;

    5160:   PetscFunctionBegin;
    5162:   PetscCall(DMGetNumFields(dm, &Nf));
    5163:   for (f = Nf; f < numFields; ++f) {
    5164:     PetscContainer obj;

    5166:     PetscCall(PetscContainerCreate(PetscObjectComm((PetscObject)dm), &obj));
    5167:     PetscCall(DMAddField(dm, NULL, (PetscObject)obj));
    5168:     PetscCall(PetscContainerDestroy(&obj));
    5169:   }
    5170:   PetscFunctionReturn(PETSC_SUCCESS);
    5171: }

    5173: /*@
    5174:   DMGetField - Return the `DMLabel` and discretization object for a given `DM` field

    5176:   Not Collective

    5178:   Input Parameters:
    5179: + dm - The `DM`
    5180: - f  - The field number

    5182:   Output Parameters:
    5183: + label - The label indicating the support of the field, or `NULL` for the entire mesh (pass in `NULL` if not needed)
    5184: - disc  - The discretization object (pass in `NULL` if not needed)

    5186:   Level: intermediate

    5188: .seealso: [](ch_dmbase), `DM`, `DMAddField()`, `DMSetField()`
    5189: @*/
    5190: PetscErrorCode DMGetField(DM dm, PetscInt f, DMLabel *label, PetscObject *disc)
    5191: {
    5192:   PetscFunctionBegin;
    5194:   PetscAssertPointer(disc, 4);
    5195:   PetscCheck((f >= 0) && (f < dm->Nf), PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Field number %" PetscInt_FMT " must be in [0, %" PetscInt_FMT ")", f, dm->Nf);
    5196:   if (!dm->fields) {
    5197:     if (label) *label = NULL;
    5198:     if (disc) *disc = NULL;
    5199:   } else { // some DM such as DMDA do not have dm->fields
    5200:     if (label) *label = dm->fields[f].label;
    5201:     if (disc) *disc = dm->fields[f].disc;
    5202:   }
    5203:   PetscFunctionReturn(PETSC_SUCCESS);
    5204: }

    5206: /* Does not clear the DS */
    5207: PetscErrorCode DMSetField_Internal(DM dm, PetscInt f, DMLabel label, PetscObject disc)
    5208: {
    5209:   PetscFunctionBegin;
    5210:   PetscCall(DMFieldEnlarge_Static(dm, f + 1));
    5211:   PetscCall(DMLabelDestroy(&dm->fields[f].label));
    5212:   PetscCall(PetscObjectDestroy(&dm->fields[f].disc));
    5213:   dm->fields[f].label = label;
    5214:   dm->fields[f].disc  = disc;
    5215:   PetscCall(PetscObjectReference((PetscObject)label));
    5216:   PetscCall(PetscObjectReference(disc));
    5217:   PetscFunctionReturn(PETSC_SUCCESS);
    5218: }

    5220: /*@
    5221:   DMSetField - Set the discretization object for a given `DM` field. Usually one would call `DMAddField()` which automatically handles
    5222:   the field numbering.

    5224:   Logically Collective

    5226:   Input Parameters:
    5227: + dm    - The `DM`
    5228: . f     - The field number
    5229: . label - The label indicating the support of the field, or `NULL` for the entire mesh
    5230: - disc  - The discretization object

    5232:   Level: intermediate

    5234: .seealso: [](ch_dmbase), `DM`, `DMAddField()`, `DMGetField()`
    5235: @*/
    5236: PetscErrorCode DMSetField(DM dm, PetscInt f, DMLabel label, PetscObject disc)
    5237: {
    5238:   PetscFunctionBegin;
    5242:   PetscCheck(f >= 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Field number %" PetscInt_FMT " must be non-negative", f);
    5243:   PetscCall(DMSetField_Internal(dm, f, label, disc));
    5244:   PetscCall(DMSetDefaultAdjacency_Private(dm, f, disc));
    5245:   PetscCall(DMClearDS(dm));
    5246:   PetscFunctionReturn(PETSC_SUCCESS);
    5247: }

    5249: /*@
    5250:   DMAddField - Add a field to a `DM` object. A field is a function space defined by of a set of discretization points (geometric entities)
    5251:   and a discretization object that defines the function space associated with those points.

    5253:   Logically Collective

    5255:   Input Parameters:
    5256: + dm    - The `DM`
    5257: . label - The label indicating the support of the field, or `NULL` for the entire mesh
    5258: - disc  - The discretization object

    5260:   Level: intermediate

    5262:   Notes:
    5263:   The label already exists or will be added to the `DM` with `DMSetLabel()`.

    5265:   For example, a piecewise continuous pressure field can be defined by coefficients at the cell centers of a mesh and piecewise constant functions
    5266:   within each cell. Thus a specific function in the space is defined by the combination of a `Vec` containing the coefficients, a `DM` defining the
    5267:   geometry entities, a `DMLabel` indicating a subset of those geometric entities, and a discretization object, such as a `PetscFE`.

    5269:   Fortran Note:
    5270:   Use the argument `PetscObjectCast(disc)` as the second argument

    5272: .seealso: [](ch_dmbase), `DM`, `DMSetLabel()`, `DMSetField()`, `DMGetField()`, `PetscFE`
    5273: @*/
    5274: PetscErrorCode DMAddField(DM dm, DMLabel label, PetscObject disc)
    5275: {
    5276:   PetscInt Nf = dm->Nf;

    5278:   PetscFunctionBegin;
    5282:   PetscCall(DMFieldEnlarge_Static(dm, Nf + 1));
    5283:   dm->fields[Nf].label = label;
    5284:   dm->fields[Nf].disc  = disc;
    5285:   PetscCall(PetscObjectReference((PetscObject)label));
    5286:   PetscCall(PetscObjectReference(disc));
    5287:   PetscCall(DMSetDefaultAdjacency_Private(dm, Nf, disc));
    5288:   PetscCall(DMClearDS(dm));
    5289:   PetscFunctionReturn(PETSC_SUCCESS);
    5290: }

    5292: /*@
    5293:   DMSetFieldAvoidTensor - Set flag to avoid defining the field on tensor cells

    5295:   Logically Collective

    5297:   Input Parameters:
    5298: + dm          - The `DM`
    5299: . f           - The field index
    5300: - avoidTensor - `PETSC_TRUE` to skip defining the field on tensor cells

    5302:   Level: intermediate

    5304: .seealso: [](ch_dmbase), `DM`, `DMGetFieldAvoidTensor()`, `DMSetField()`, `DMGetField()`
    5305: @*/
    5306: PetscErrorCode DMSetFieldAvoidTensor(DM dm, PetscInt f, PetscBool avoidTensor)
    5307: {
    5308:   PetscFunctionBegin;
    5309:   PetscCheck((f >= 0) && (f < dm->Nf), PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_OUTOFRANGE, "Field %" PetscInt_FMT " is not in [0, %" PetscInt_FMT ")", f, dm->Nf);
    5310:   dm->fields[f].avoidTensor = avoidTensor;
    5311:   PetscFunctionReturn(PETSC_SUCCESS);
    5312: }

    5314: /*@
    5315:   DMGetFieldAvoidTensor - Get flag to avoid defining the field on tensor cells

    5317:   Not Collective

    5319:   Input Parameters:
    5320: + dm - The `DM`
    5321: - f  - The field index

    5323:   Output Parameter:
    5324: . avoidTensor - The flag to avoid defining the field on tensor cells

    5326:   Level: intermediate

    5328: .seealso: [](ch_dmbase), `DM`, `DMAddField()`, `DMSetField()`, `DMGetField()`, `DMSetFieldAvoidTensor()`
    5329: @*/
    5330: PetscErrorCode DMGetFieldAvoidTensor(DM dm, PetscInt f, PetscBool *avoidTensor)
    5331: {
    5332:   PetscFunctionBegin;
    5333:   PetscCheck((f >= 0) && (f < dm->Nf), PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_OUTOFRANGE, "Field %" PetscInt_FMT " is not in [0, %" PetscInt_FMT ")", f, dm->Nf);
    5334:   *avoidTensor = dm->fields[f].avoidTensor;
    5335:   PetscFunctionReturn(PETSC_SUCCESS);
    5336: }

    5338: /*@
    5339:   DMCopyFields - Copy the discretizations for the `DM` into another `DM`

    5341:   Collective

    5343:   Input Parameters:
    5344: + dm        - The `DM`
    5345: . minDegree - Minimum degree for a discretization, or `PETSC_DETERMINE` for no limit
    5346: - maxDegree - Maximum degree for a discretization, or `PETSC_DETERMINE` for no limit

    5348:   Output Parameter:
    5349: . newdm - The `DM`

    5351:   Level: advanced

    5353: .seealso: [](ch_dmbase), `DM`, `DMGetField()`, `DMSetField()`, `DMAddField()`, `DMCopyDS()`, `DMGetDS()`, `DMGetCellDS()`
    5354: @*/
    5355: PetscErrorCode DMCopyFields(DM dm, PetscInt minDegree, PetscInt maxDegree, DM newdm)
    5356: {
    5357:   PetscInt Nf, f;

    5359:   PetscFunctionBegin;
    5360:   if (dm == newdm) PetscFunctionReturn(PETSC_SUCCESS);
    5361:   PetscCall(DMGetNumFields(dm, &Nf));
    5362:   PetscCall(DMClearFields(newdm));
    5363:   for (f = 0; f < Nf; ++f) {
    5364:     DMLabel      label;
    5365:     PetscObject  field;
    5366:     PetscClassId id;
    5367:     PetscBool    useCone, useClosure;

    5369:     PetscCall(DMGetField(dm, f, &label, &field));
    5370:     PetscCall(PetscObjectGetClassId(field, &id));
    5371:     if (id == PETSCFE_CLASSID) {
    5372:       PetscFE newfe;

    5374:       PetscCall(PetscFELimitDegree((PetscFE)field, minDegree, maxDegree, &newfe));
    5375:       PetscCall(DMSetField(newdm, f, label, (PetscObject)newfe));
    5376:       PetscCall(PetscFEDestroy(&newfe));
    5377:     } else {
    5378:       PetscCall(DMSetField(newdm, f, label, field));
    5379:     }
    5380:     PetscCall(DMGetAdjacency(dm, f, &useCone, &useClosure));
    5381:     PetscCall(DMSetAdjacency(newdm, f, useCone, useClosure));
    5382:   }
    5383:   // Create nullspace constructor slots
    5384:   if (dm->nullspaceConstructors) {
    5385:     PetscCall(PetscFree2(newdm->nullspaceConstructors, newdm->nearnullspaceConstructors));
    5386:     PetscCall(PetscCalloc2(Nf, &newdm->nullspaceConstructors, Nf, &newdm->nearnullspaceConstructors));
    5387:   }
    5388:   PetscFunctionReturn(PETSC_SUCCESS);
    5389: }

    5391: /*@
    5392:   DMGetAdjacency - Returns the flags for determining variable influence

    5394:   Not Collective

    5396:   Input Parameters:
    5397: + dm - The `DM` object
    5398: - f  - The field number, or `PETSC_DEFAULT` for the default adjacency

    5400:   Output Parameters:
    5401: + useCone    - Flag for variable influence starting with the cone operation
    5402: - useClosure - Flag for variable influence using transitive closure

    5404:   Level: developer

    5406:   Notes:
    5407: .vb
    5408:      FEM:   Two points p and q are adjacent if q \in closure(star(p)),   useCone = PETSC_FALSE, useClosure = PETSC_TRUE
    5409:      FVM:   Two points p and q are adjacent if q \in support(p+cone(p)), useCone = PETSC_TRUE,  useClosure = PETSC_FALSE
    5410:      FVM++: Two points p and q are adjacent if q \in star(closure(p)),   useCone = PETSC_TRUE,  useClosure = PETSC_TRUE
    5411: .ve
    5412:   Further explanation can be found in the User's Manual Section on the Influence of Variables on One Another.

    5414: .seealso: [](ch_dmbase), `DM`, `DMSetAdjacency()`, `DMGetField()`, `DMSetField()`
    5415: @*/
    5416: PetscErrorCode DMGetAdjacency(DM dm, PetscInt f, PetscBool *useCone, PetscBool *useClosure)
    5417: {
    5418:   PetscFunctionBegin;
    5420:   if (useCone) PetscAssertPointer(useCone, 3);
    5421:   if (useClosure) PetscAssertPointer(useClosure, 4);
    5422:   if (f < 0) {
    5423:     if (useCone) *useCone = dm->adjacency[0];
    5424:     if (useClosure) *useClosure = dm->adjacency[1];
    5425:   } else {
    5426:     PetscInt Nf;

    5428:     PetscCall(DMGetNumFields(dm, &Nf));
    5429:     PetscCheck(f < Nf, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Field number %" PetscInt_FMT " must be in [0, %" PetscInt_FMT ")", f, Nf);
    5430:     if (useCone) *useCone = dm->fields[f].adjacency[0];
    5431:     if (useClosure) *useClosure = dm->fields[f].adjacency[1];
    5432:   }
    5433:   PetscFunctionReturn(PETSC_SUCCESS);
    5434: }

    5436: /*@
    5437:   DMSetAdjacency - Set the flags for determining variable influence

    5439:   Not Collective

    5441:   Input Parameters:
    5442: + dm         - The `DM` object
    5443: . f          - The field number
    5444: . useCone    - Flag for variable influence starting with the cone operation
    5445: - useClosure - Flag for variable influence using transitive closure

    5447:   Level: developer

    5449:   Notes:
    5450: .vb
    5451:      FEM:   Two points p and q are adjacent if q \in closure(star(p)),   useCone = PETSC_FALSE, useClosure = PETSC_TRUE
    5452:      FVM:   Two points p and q are adjacent if q \in support(p+cone(p)), useCone = PETSC_TRUE,  useClosure = PETSC_FALSE
    5453:      FVM++: Two points p and q are adjacent if q \in star(closure(p)),   useCone = PETSC_TRUE,  useClosure = PETSC_TRUE
    5454: .ve
    5455:   Further explanation can be found in the User's Manual Section on the Influence of Variables on One Another.

    5457: .seealso: [](ch_dmbase), `DM`, `DMGetAdjacency()`, `DMGetField()`, `DMSetField()`
    5458: @*/
    5459: PetscErrorCode DMSetAdjacency(DM dm, PetscInt f, PetscBool useCone, PetscBool useClosure)
    5460: {
    5461:   PetscFunctionBegin;
    5463:   if (f < 0) {
    5464:     dm->adjacency[0] = useCone;
    5465:     dm->adjacency[1] = useClosure;
    5466:   } else {
    5467:     PetscInt Nf;

    5469:     PetscCall(DMGetNumFields(dm, &Nf));
    5470:     PetscCheck(f < Nf, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Field number %" PetscInt_FMT " must be in [0, %" PetscInt_FMT ")", f, Nf);
    5471:     dm->fields[f].adjacency[0] = useCone;
    5472:     dm->fields[f].adjacency[1] = useClosure;
    5473:   }
    5474:   PetscFunctionReturn(PETSC_SUCCESS);
    5475: }

    5477: /*@
    5478:   DMGetBasicAdjacency - Returns the flags for determining variable influence, using either the default or field 0 if it is defined

    5480:   Not collective

    5482:   Input Parameter:
    5483: . dm - The `DM` object

    5485:   Output Parameters:
    5486: + useCone    - Flag for variable influence starting with the cone operation
    5487: - useClosure - Flag for variable influence using transitive closure

    5489:   Level: developer

    5491:   Notes:
    5492: .vb
    5493:      FEM:   Two points p and q are adjacent if q \in closure(star(p)),   useCone = PETSC_FALSE, useClosure = PETSC_TRUE
    5494:      FVM:   Two points p and q are adjacent if q \in support(p+cone(p)), useCone = PETSC_TRUE,  useClosure = PETSC_FALSE
    5495:      FVM++: Two points p and q are adjacent if q \in star(closure(p)),   useCone = PETSC_TRUE,  useClosure = PETSC_TRUE
    5496: .ve

    5498: .seealso: [](ch_dmbase), `DM`, `DMSetBasicAdjacency()`, `DMGetField()`, `DMSetField()`
    5499: @*/
    5500: PetscErrorCode DMGetBasicAdjacency(DM dm, PetscBool *useCone, PetscBool *useClosure)
    5501: {
    5502:   PetscInt Nf;

    5504:   PetscFunctionBegin;
    5506:   if (useCone) PetscAssertPointer(useCone, 2);
    5507:   if (useClosure) PetscAssertPointer(useClosure, 3);
    5508:   PetscCall(DMGetNumFields(dm, &Nf));
    5509:   if (!Nf) {
    5510:     PetscCall(DMGetAdjacency(dm, PETSC_DEFAULT, useCone, useClosure));
    5511:   } else {
    5512:     PetscCall(DMGetAdjacency(dm, 0, useCone, useClosure));
    5513:   }
    5514:   PetscFunctionReturn(PETSC_SUCCESS);
    5515: }

    5517: /*@
    5518:   DMSetBasicAdjacency - Set the flags for determining variable influence, using either the default or field 0 if it is defined

    5520:   Not Collective

    5522:   Input Parameters:
    5523: + dm         - The `DM` object
    5524: . useCone    - Flag for variable influence starting with the cone operation
    5525: - useClosure - Flag for variable influence using transitive closure

    5527:   Level: developer

    5529:   Notes:
    5530: .vb
    5531:      FEM:   Two points p and q are adjacent if q \in closure(star(p)),   useCone = PETSC_FALSE, useClosure = PETSC_TRUE
    5532:      FVM:   Two points p and q are adjacent if q \in support(p+cone(p)), useCone = PETSC_TRUE,  useClosure = PETSC_FALSE
    5533:      FVM++: Two points p and q are adjacent if q \in star(closure(p)),   useCone = PETSC_TRUE,  useClosure = PETSC_TRUE
    5534: .ve

    5536: .seealso: [](ch_dmbase), `DM`, `DMGetBasicAdjacency()`, `DMGetField()`, `DMSetField()`
    5537: @*/
    5538: PetscErrorCode DMSetBasicAdjacency(DM dm, PetscBool useCone, PetscBool useClosure)
    5539: {
    5540:   PetscInt Nf;

    5542:   PetscFunctionBegin;
    5544:   PetscCall(DMGetNumFields(dm, &Nf));
    5545:   if (!Nf) {
    5546:     PetscCall(DMSetAdjacency(dm, PETSC_DEFAULT, useCone, useClosure));
    5547:   } else {
    5548:     PetscCall(DMSetAdjacency(dm, 0, useCone, useClosure));
    5549:   }
    5550:   PetscFunctionReturn(PETSC_SUCCESS);
    5551: }

    5553: PetscErrorCode DMCompleteBCLabels_Internal(DM dm)
    5554: {
    5555:   DM           plex;
    5556:   DMLabel     *labels, *glabels;
    5557:   const char **names;
    5558:   char        *sendNames, *recvNames;
    5559:   PetscInt     Nds, s, maxLabels = 0, maxLen = 0, gmaxLen, Nl = 0, gNl, l, gl, m;
    5560:   size_t       len;
    5561:   MPI_Comm     comm;
    5562:   PetscMPIInt  rank, size, p, *counts, *displs;

    5564:   PetscFunctionBegin;
    5565:   PetscCall(PetscObjectGetComm((PetscObject)dm, &comm));
    5566:   PetscCallMPI(MPI_Comm_size(comm, &size));
    5567:   PetscCallMPI(MPI_Comm_rank(comm, &rank));
    5568:   PetscCall(DMGetNumDS(dm, &Nds));
    5569:   for (s = 0; s < Nds; ++s) {
    5570:     PetscDS  dsBC;
    5571:     PetscInt numBd;

    5573:     PetscCall(DMGetRegionNumDS(dm, s, NULL, NULL, &dsBC, NULL));
    5574:     PetscCall(PetscDSGetNumBoundary(dsBC, &numBd));
    5575:     maxLabels += numBd;
    5576:   }
    5577:   PetscCall(PetscCalloc1(maxLabels, &labels));
    5578:   /* Get list of labels to be completed */
    5579:   for (s = 0; s < Nds; ++s) {
    5580:     PetscDS  dsBC;
    5581:     PetscInt numBd, bd;

    5583:     PetscCall(DMGetRegionNumDS(dm, s, NULL, NULL, &dsBC, NULL));
    5584:     PetscCall(PetscDSGetNumBoundary(dsBC, &numBd));
    5585:     for (bd = 0; bd < numBd; ++bd) {
    5586:       DMLabel      label;
    5587:       PetscInt     field;
    5588:       PetscObject  obj;
    5589:       PetscClassId id;

    5591:       PetscCall(PetscDSGetBoundary(dsBC, bd, NULL, NULL, NULL, &label, NULL, NULL, &field, NULL, NULL, NULL, NULL, NULL));
    5592:       PetscCall(DMGetField(dm, field, NULL, &obj));
    5593:       PetscCall(PetscObjectGetClassId(obj, &id));
    5594:       if (id != PETSCFE_CLASSID || !label) continue;
    5595:       for (l = 0; l < Nl; ++l)
    5596:         if (labels[l] == label) break;
    5597:       if (l == Nl) labels[Nl++] = label;
    5598:     }
    5599:   }
    5600:   /* Get label names */
    5601:   PetscCall(PetscMalloc1(Nl, &names));
    5602:   for (l = 0; l < Nl; ++l) PetscCall(PetscObjectGetName((PetscObject)labels[l], &names[l]));
    5603:   for (l = 0; l < Nl; ++l) {
    5604:     PetscCall(PetscStrlen(names[l], &len));
    5605:     maxLen = PetscMax(maxLen, (PetscInt)len + 2);
    5606:   }
    5607:   PetscCall(PetscFree(labels));
    5608:   PetscCallMPI(MPIU_Allreduce(&maxLen, &gmaxLen, 1, MPIU_INT, MPI_MAX, comm));
    5609:   PetscCall(PetscCalloc1(Nl * gmaxLen, &sendNames));
    5610:   for (l = 0; l < Nl; ++l) PetscCall(PetscStrncpy(&sendNames[gmaxLen * l], names[l], gmaxLen));
    5611:   PetscCall(PetscFree(names));
    5612:   /* Put all names on all processes */
    5613:   PetscCall(PetscCalloc2(size, &counts, size + 1, &displs));
    5614:   PetscCallMPI(MPI_Allgather(&Nl, 1, MPI_INT, counts, 1, MPI_INT, comm));
    5615:   for (p = 0; p < size; ++p) displs[p + 1] = displs[p] + counts[p];
    5616:   gNl = displs[size];
    5617:   for (p = 0; p < size; ++p) {
    5618:     counts[p] *= gmaxLen;
    5619:     displs[p] *= gmaxLen;
    5620:   }
    5621:   PetscCall(PetscCalloc2(gNl * gmaxLen, &recvNames, gNl, &glabels));
    5622:   PetscCallMPI(MPI_Allgatherv(sendNames, counts[rank], MPI_CHAR, recvNames, counts, displs, MPI_CHAR, comm));
    5623:   PetscCall(PetscFree2(counts, displs));
    5624:   PetscCall(PetscFree(sendNames));
    5625:   for (l = 0, gl = 0; l < gNl; ++l) {
    5626:     PetscCall(DMGetLabel(dm, &recvNames[l * gmaxLen], &glabels[gl]));
    5627:     PetscCheck(glabels[gl], PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Label %s missing on rank %d", &recvNames[l * gmaxLen], rank);
    5628:     for (m = 0; m < gl; ++m)
    5629:       if (glabels[m] == glabels[gl]) goto next_label;
    5630:     PetscCall(DMConvert(dm, DMPLEX, &plex));
    5631:     PetscCall(DMPlexLabelComplete(plex, glabels[gl]));
    5632:     PetscCall(DMDestroy(&plex));
    5633:     ++gl;
    5634:   next_label:
    5635:     continue;
    5636:   }
    5637:   PetscCall(PetscFree2(recvNames, glabels));
    5638:   PetscFunctionReturn(PETSC_SUCCESS);
    5639: }

    5641: static PetscErrorCode DMDSEnlarge_Static(DM dm, PetscInt NdsNew)
    5642: {
    5643:   DMSpace *tmpd;
    5644:   PetscInt Nds = dm->Nds, s;

    5646:   PetscFunctionBegin;
    5647:   if (Nds >= NdsNew) PetscFunctionReturn(PETSC_SUCCESS);
    5648:   PetscCall(PetscMalloc1(NdsNew, &tmpd));
    5649:   for (s = 0; s < Nds; ++s) tmpd[s] = dm->probs[s];
    5650:   for (s = Nds; s < NdsNew; ++s) {
    5651:     tmpd[s].ds     = NULL;
    5652:     tmpd[s].label  = NULL;
    5653:     tmpd[s].fields = NULL;
    5654:   }
    5655:   PetscCall(PetscFree(dm->probs));
    5656:   dm->Nds   = NdsNew;
    5657:   dm->probs = tmpd;
    5658:   PetscFunctionReturn(PETSC_SUCCESS);
    5659: }

    5661: /*@
    5662:   DMGetNumDS - Get the number of discrete systems in the `DM`

    5664:   Not Collective

    5666:   Input Parameter:
    5667: . dm - The `DM`

    5669:   Output Parameter:
    5670: . Nds - The number of `PetscDS` objects

    5672:   Level: intermediate

    5674: .seealso: [](ch_dmbase), `DM`, `DMGetDS()`, `DMGetCellDS()`
    5675: @*/
    5676: PetscErrorCode DMGetNumDS(DM dm, PetscInt *Nds)
    5677: {
    5678:   PetscFunctionBegin;
    5680:   PetscAssertPointer(Nds, 2);
    5681:   *Nds = dm->Nds;
    5682:   PetscFunctionReturn(PETSC_SUCCESS);
    5683: }

    5685: /*@
    5686:   DMClearDS - Remove all discrete systems from the `DM`

    5688:   Logically Collective

    5690:   Input Parameter:
    5691: . dm - The `DM`

    5693:   Level: intermediate

    5695: .seealso: [](ch_dmbase), `DM`, `DMGetNumDS()`, `DMGetDS()`, `DMSetField()`
    5696: @*/
    5697: PetscErrorCode DMClearDS(DM dm)
    5698: {
    5699:   PetscInt s;

    5701:   PetscFunctionBegin;
    5703:   for (s = 0; s < dm->Nds; ++s) {
    5704:     PetscCall(PetscDSDestroy(&dm->probs[s].ds));
    5705:     PetscCall(PetscDSDestroy(&dm->probs[s].dsIn));
    5706:     PetscCall(DMLabelDestroy(&dm->probs[s].label));
    5707:     PetscCall(ISDestroy(&dm->probs[s].fields));
    5708:   }
    5709:   PetscCall(PetscFree(dm->probs));
    5710:   dm->probs = NULL;
    5711:   dm->Nds   = 0;
    5712:   PetscFunctionReturn(PETSC_SUCCESS);
    5713: }

    5715: /*@
    5716:   DMGetDS - Get the default `PetscDS`

    5718:   Not Collective

    5720:   Input Parameter:
    5721: . dm - The `DM`

    5723:   Output Parameter:
    5724: . ds - The default `PetscDS`

    5726:   Level: intermediate

    5728:   Note:
    5729:   The `ds` is owned by the `dm` and should not be destroyed directly.

    5731: .seealso: [](ch_dmbase), `DM`, `DMGetCellDS()`, `DMGetRegionDS()`
    5732: @*/
    5733: PetscErrorCode DMGetDS(DM dm, PetscDS *ds)
    5734: {
    5735:   PetscFunctionBeginHot;
    5737:   PetscAssertPointer(ds, 2);
    5738:   PetscCheck(dm->Nds > 0, PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_WRONGSTATE, "Need to call DMCreateDS() before calling DMGetDS()");
    5739:   *ds = dm->probs[0].ds;
    5740:   PetscFunctionReturn(PETSC_SUCCESS);
    5741: }

    5743: /*@
    5744:   DMGetCellDS - Get the `PetscDS` defined on a given cell

    5746:   Not Collective

    5748:   Input Parameters:
    5749: + dm    - The `DM`
    5750: - point - Cell for the `PetscDS`

    5752:   Output Parameters:
    5753: + ds   - The `PetscDS` defined on the given cell
    5754: - dsIn - The `PetscDS` for input on the given cell, or `NULL` if the same ds

    5756:   Level: developer

    5758: .seealso: [](ch_dmbase), `DM`, `DMGetDS()`, `DMSetRegionDS()`
    5759: @*/
    5760: PetscErrorCode DMGetCellDS(DM dm, PetscInt point, PetscDS *ds, PetscDS *dsIn)
    5761: {
    5762:   PetscDS  dsDef = NULL;
    5763:   PetscInt s;

    5765:   PetscFunctionBeginHot;
    5767:   if (ds) PetscAssertPointer(ds, 3);
    5768:   if (dsIn) PetscAssertPointer(dsIn, 4);
    5769:   PetscCheck(point >= 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Mesh point cannot be negative: %" PetscInt_FMT, point);
    5770:   if (ds) *ds = NULL;
    5771:   if (dsIn) *dsIn = NULL;
    5772:   for (s = 0; s < dm->Nds; ++s) {
    5773:     PetscInt val;

    5775:     if (!dm->probs[s].label) {
    5776:       dsDef = dm->probs[s].ds;
    5777:     } else {
    5778:       PetscCall(DMLabelGetValue(dm->probs[s].label, point, &val));
    5779:       if (val >= 0) {
    5780:         if (ds) *ds = dm->probs[s].ds;
    5781:         if (dsIn) *dsIn = dm->probs[s].dsIn;
    5782:         break;
    5783:       }
    5784:     }
    5785:   }
    5786:   if (ds && !*ds) *ds = dsDef;
    5787:   PetscFunctionReturn(PETSC_SUCCESS);
    5788: }

    5790: /*@
    5791:   DMGetRegionDS - Get the `PetscDS` for a given mesh region, defined by a `DMLabel`

    5793:   Not Collective

    5795:   Input Parameters:
    5796: + dm    - The `DM`
    5797: - label - The `DMLabel` defining the mesh region, or `NULL` for the entire mesh

    5799:   Output Parameters:
    5800: + fields - The `IS` containing the `DM` field numbers for the fields in this `PetscDS`, or `NULL`
    5801: . ds     - The `PetscDS` defined on the given region, or `NULL`
    5802: - dsIn   - The `PetscDS` for input in the given region, or `NULL`

    5804:   Level: advanced

    5806:   Note:
    5807:   If a non-`NULL` label is given, but there is no `PetscDS` on that specific label,
    5808:   the `PetscDS` for the full domain (if present) is returned. Returns with
    5809:   fields = `NULL` and ds = `NULL` if there is no `PetscDS` for the full domain.

    5811: .seealso: [](ch_dmbase), `DM`, `DMGetRegionNumDS()`, `DMSetRegionDS()`, `DMGetDS()`, `DMGetCellDS()`
    5812: @*/
    5813: PetscErrorCode DMGetRegionDS(DM dm, DMLabel label, IS *fields, PetscDS *ds, PetscDS *dsIn)
    5814: {
    5815:   PetscInt Nds = dm->Nds, s;

    5817:   PetscFunctionBegin;
    5820:   if (fields) {
    5821:     PetscAssertPointer(fields, 3);
    5822:     *fields = NULL;
    5823:   }
    5824:   if (ds) {
    5825:     PetscAssertPointer(ds, 4);
    5826:     *ds = NULL;
    5827:   }
    5828:   if (dsIn) {
    5829:     PetscAssertPointer(dsIn, 5);
    5830:     *dsIn = NULL;
    5831:   }
    5832:   for (s = 0; s < Nds; ++s) {
    5833:     if (dm->probs[s].label == label || !dm->probs[s].label) {
    5834:       if (fields) *fields = dm->probs[s].fields;
    5835:       if (ds) *ds = dm->probs[s].ds;
    5836:       if (dsIn) *dsIn = dm->probs[s].dsIn;
    5837:       if (dm->probs[s].label) PetscFunctionReturn(PETSC_SUCCESS);
    5838:     }
    5839:   }
    5840:   PetscFunctionReturn(PETSC_SUCCESS);
    5841: }

    5843: /*@
    5844:   DMSetRegionDS - Set the `PetscDS` for a given mesh region, defined by a `DMLabel`

    5846:   Collective

    5848:   Input Parameters:
    5849: + dm     - The `DM`
    5850: . label  - The `DMLabel` defining the mesh region, or `NULL` for the entire mesh
    5851: . fields - The `IS` containing the `DM` field numbers for the fields in this `PetscDS`, or `NULL` for all fields
    5852: . ds     - The `PetscDS` defined on the given region
    5853: - dsIn   - The `PetscDS` for input on the given cell, or `NULL` if it is the same `PetscDS`

    5855:   Level: advanced

    5857:   Note:
    5858:   If the label has a `PetscDS` defined, it will be replaced. Otherwise, it will be added to the `DM`. If the `PetscDS` is replaced,
    5859:   the fields argument is ignored.

    5861: .seealso: [](ch_dmbase), `DM`, `DMGetRegionDS()`, `DMSetRegionNumDS()`, `DMGetDS()`, `DMGetCellDS()`
    5862: @*/
    5863: PetscErrorCode DMSetRegionDS(DM dm, DMLabel label, IS fields, PetscDS ds, PetscDS dsIn)
    5864: {
    5865:   PetscInt Nds = dm->Nds, s;

    5867:   PetscFunctionBegin;
    5873:   for (s = 0; s < Nds; ++s) {
    5874:     if (dm->probs[s].label == label) {
    5875:       PetscCall(PetscDSDestroy(&dm->probs[s].ds));
    5876:       PetscCall(PetscDSDestroy(&dm->probs[s].dsIn));
    5877:       dm->probs[s].ds   = ds;
    5878:       dm->probs[s].dsIn = dsIn;
    5879:       PetscFunctionReturn(PETSC_SUCCESS);
    5880:     }
    5881:   }
    5882:   PetscCall(DMDSEnlarge_Static(dm, Nds + 1));
    5883:   PetscCall(PetscObjectReference((PetscObject)label));
    5884:   PetscCall(PetscObjectReference((PetscObject)fields));
    5885:   PetscCall(PetscObjectReference((PetscObject)ds));
    5886:   PetscCall(PetscObjectReference((PetscObject)dsIn));
    5887:   if (!label) {
    5888:     /* Put the NULL label at the front, so it is returned as the default */
    5889:     for (s = Nds - 1; s >= 0; --s) dm->probs[s + 1] = dm->probs[s];
    5890:     Nds = 0;
    5891:   }
    5892:   dm->probs[Nds].label  = label;
    5893:   dm->probs[Nds].fields = fields;
    5894:   dm->probs[Nds].ds     = ds;
    5895:   dm->probs[Nds].dsIn   = dsIn;
    5896:   PetscFunctionReturn(PETSC_SUCCESS);
    5897: }

    5899: /*@
    5900:   DMGetRegionNumDS - Get the `PetscDS` for a given mesh region, defined by the region number

    5902:   Not Collective

    5904:   Input Parameters:
    5905: + dm  - The `DM`
    5906: - num - The region number, in [0, Nds)

    5908:   Output Parameters:
    5909: + label  - The region label, or `NULL`
    5910: . fields - The `IS` containing the `DM` field numbers for the fields in this `PetscDS`, or `NULL`
    5911: . ds     - The `PetscDS` defined on the given region, or `NULL`
    5912: - dsIn   - The `PetscDS` for input in the given region, or `NULL`

    5914:   Level: advanced

    5916: .seealso: [](ch_dmbase), `DM`, `DMGetRegionDS()`, `DMSetRegionDS()`, `DMGetDS()`, `DMGetCellDS()`
    5917: @*/
    5918: PetscErrorCode DMGetRegionNumDS(DM dm, PetscInt num, DMLabel *label, IS *fields, PetscDS *ds, PetscDS *dsIn)
    5919: {
    5920:   PetscInt Nds;

    5922:   PetscFunctionBegin;
    5924:   PetscCall(DMGetNumDS(dm, &Nds));
    5925:   PetscCheck((num >= 0) && (num < Nds), PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Region number %" PetscInt_FMT " is not in [0, %" PetscInt_FMT ")", num, Nds);
    5926:   if (label) {
    5927:     PetscAssertPointer(label, 3);
    5928:     *label = dm->probs[num].label;
    5929:   }
    5930:   if (fields) {
    5931:     PetscAssertPointer(fields, 4);
    5932:     *fields = dm->probs[num].fields;
    5933:   }
    5934:   if (ds) {
    5935:     PetscAssertPointer(ds, 5);
    5936:     *ds = dm->probs[num].ds;
    5937:   }
    5938:   if (dsIn) {
    5939:     PetscAssertPointer(dsIn, 6);
    5940:     *dsIn = dm->probs[num].dsIn;
    5941:   }
    5942:   PetscFunctionReturn(PETSC_SUCCESS);
    5943: }

    5945: /*@
    5946:   DMSetRegionNumDS - Set the `PetscDS` for a given mesh region, defined by the region number

    5948:   Not Collective

    5950:   Input Parameters:
    5951: + dm     - The `DM`
    5952: . num    - The region number, in [0, Nds)
    5953: . label  - The region label, or `NULL`
    5954: . fields - The `IS` containing the `DM` field numbers for the fields in this `PetscDS`, or `NULL` to prevent setting
    5955: . ds     - The `PetscDS` defined on the given region, or `NULL` to prevent setting
    5956: - dsIn   - The `PetscDS` for input on the given cell, or `NULL` if it is the same `PetscDS`

    5958:   Level: advanced

    5960: .seealso: [](ch_dmbase), `DM`, `DMGetRegionDS()`, `DMSetRegionDS()`, `DMGetDS()`, `DMGetCellDS()`
    5961: @*/
    5962: PetscErrorCode DMSetRegionNumDS(DM dm, PetscInt num, DMLabel label, IS fields, PetscDS ds, PetscDS dsIn)
    5963: {
    5964:   PetscInt Nds;

    5966:   PetscFunctionBegin;
    5969:   PetscCall(DMGetNumDS(dm, &Nds));
    5970:   PetscCheck((num >= 0) && (num < Nds), PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Region number %" PetscInt_FMT " is not in [0, %" PetscInt_FMT ")", num, Nds);
    5971:   PetscCall(PetscObjectReference((PetscObject)label));
    5972:   PetscCall(DMLabelDestroy(&dm->probs[num].label));
    5973:   dm->probs[num].label = label;
    5974:   if (fields) {
    5976:     PetscCall(PetscObjectReference((PetscObject)fields));
    5977:     PetscCall(ISDestroy(&dm->probs[num].fields));
    5978:     dm->probs[num].fields = fields;
    5979:   }
    5980:   if (ds) {
    5982:     PetscCall(PetscObjectReference((PetscObject)ds));
    5983:     PetscCall(PetscDSDestroy(&dm->probs[num].ds));
    5984:     dm->probs[num].ds = ds;
    5985:   }
    5986:   if (dsIn) {
    5988:     PetscCall(PetscObjectReference((PetscObject)dsIn));
    5989:     PetscCall(PetscDSDestroy(&dm->probs[num].dsIn));
    5990:     dm->probs[num].dsIn = dsIn;
    5991:   }
    5992:   PetscFunctionReturn(PETSC_SUCCESS);
    5993: }

    5995: /*@
    5996:   DMFindRegionNum - Find the region number for a given `PetscDS`, or -1 if it is not found.

    5998:   Not Collective

    6000:   Input Parameters:
    6001: + dm - The `DM`
    6002: - ds - The `PetscDS` defined on the given region

    6004:   Output Parameter:
    6005: . num - The region number, in [0, Nds), or -1 if not found

    6007:   Level: advanced

    6009: .seealso: [](ch_dmbase), `DM`, `DMGetRegionNumDS()`, `DMGetRegionDS()`, `DMSetRegionDS()`, `DMGetDS()`, `DMGetCellDS()`
    6010: @*/
    6011: PetscErrorCode DMFindRegionNum(DM dm, PetscDS ds, PetscInt *num)
    6012: {
    6013:   PetscInt Nds, n;

    6015:   PetscFunctionBegin;
    6018:   PetscAssertPointer(num, 3);
    6019:   PetscCall(DMGetNumDS(dm, &Nds));
    6020:   for (n = 0; n < Nds; ++n)
    6021:     if (ds == dm->probs[n].ds) break;
    6022:   if (n >= Nds) *num = -1;
    6023:   else *num = n;
    6024:   PetscFunctionReturn(PETSC_SUCCESS);
    6025: }

    6027: /*@
    6028:   DMCreateFEDefault - Create a `PetscFE` based on the celltype for the mesh

    6030:   Not Collective

    6032:   Input Parameters:
    6033: + dm     - The `DM`
    6034: . Nc     - The number of components for the field
    6035: . prefix - The options prefix for the output `PetscFE`, or `NULL`
    6036: - qorder - The quadrature order or `PETSC_DETERMINE` to use `PetscSpace` polynomial degree

    6038:   Output Parameter:
    6039: . fem - The `PetscFE`

    6041:   Level: intermediate

    6043:   Note:
    6044:   This is a convenience method that just calls `PetscFECreateByCell()` underneath.

    6046: .seealso: [](ch_dmbase), `DM`, `PetscFECreateByCell()`, `DMAddField()`, `DMCreateDS()`, `DMGetCellDS()`, `DMGetRegionDS()`
    6047: @*/
    6048: PetscErrorCode DMCreateFEDefault(DM dm, PetscInt Nc, const char prefix[], PetscInt qorder, PetscFE *fem)
    6049: {
    6050:   DMPolytopeType ct;
    6051:   PetscInt       dim, cStart;

    6053:   PetscFunctionBegin;
    6056:   if (prefix) PetscAssertPointer(prefix, 3);
    6058:   PetscAssertPointer(fem, 5);
    6059:   PetscCall(DMGetDimension(dm, &dim));
    6060:   PetscCall(DMPlexGetHeightStratum(dm, 0, &cStart, NULL));
    6061:   PetscCall(DMPlexGetCellType(dm, cStart, &ct));
    6062:   PetscCall(PetscFECreateByCell(PETSC_COMM_SELF, dim, Nc, ct, prefix, qorder, fem));
    6063:   PetscFunctionReturn(PETSC_SUCCESS);
    6064: }

    6066: /*@
    6067:   DMCreateDS - Create the discrete systems for the `DM` based upon the fields added to the `DM`

    6069:   Collective

    6071:   Input Parameter:
    6072: . dm - The `DM`

    6074:   Options Database Key:
    6075: . -dm_petscds_view - View all the `PetscDS` objects in this `DM`

    6077:   Level: intermediate

    6079:   Developer Note:
    6080:   The name of this function is wrong. Create functions always return the created object as one of the arguments.

    6082: .seealso: [](ch_dmbase), `DM`, `DMSetField`, `DMAddField()`, `DMGetDS()`, `DMGetCellDS()`, `DMGetRegionDS()`, `DMSetRegionDS()`
    6083: @*/
    6084: PetscErrorCode DMCreateDS(DM dm)
    6085: {
    6086:   MPI_Comm  comm;
    6087:   PetscDS   dsDef;
    6088:   DMLabel  *labelSet;
    6089:   PetscInt  dE, Nf = dm->Nf, f, s, Nl, l, Ndef, k;
    6090:   PetscBool doSetup = PETSC_TRUE, flg;

    6092:   PetscFunctionBegin;
    6094:   if (!dm->fields) PetscFunctionReturn(PETSC_SUCCESS);
    6095:   PetscCall(PetscObjectGetComm((PetscObject)dm, &comm));
    6096:   PetscCall(DMGetCoordinateDim(dm, &dE));
    6097:   // Create nullspace constructor slots
    6098:   PetscCall(PetscFree2(dm->nullspaceConstructors, dm->nearnullspaceConstructors));
    6099:   PetscCall(PetscCalloc2(Nf, &dm->nullspaceConstructors, Nf, &dm->nearnullspaceConstructors));
    6100:   /* Determine how many regions we have */
    6101:   PetscCall(PetscMalloc1(Nf, &labelSet));
    6102:   Nl   = 0;
    6103:   Ndef = 0;
    6104:   for (f = 0; f < Nf; ++f) {
    6105:     DMLabel  label = dm->fields[f].label;
    6106:     PetscInt l;

    6108: #ifdef PETSC_HAVE_LIBCEED
    6109:     /* Move CEED context to discretizations */
    6110:     {
    6111:       PetscClassId id;

    6113:       PetscCall(PetscObjectGetClassId(dm->fields[f].disc, &id));
    6114:       if (id == PETSCFE_CLASSID) {
    6115:         Ceed ceed;

    6117:         PetscCall(DMGetCeed(dm, &ceed));
    6118:         PetscCall(PetscFESetCeed((PetscFE)dm->fields[f].disc, ceed));
    6119:       }
    6120:     }
    6121: #endif
    6122:     if (!label) {
    6123:       ++Ndef;
    6124:       continue;
    6125:     }
    6126:     for (l = 0; l < Nl; ++l)
    6127:       if (label == labelSet[l]) break;
    6128:     if (l < Nl) continue;
    6129:     labelSet[Nl++] = label;
    6130:   }
    6131:   /* Create default DS if there are no labels to intersect with */
    6132:   PetscCall(DMGetRegionDS(dm, NULL, NULL, &dsDef, NULL));
    6133:   if (!dsDef && Ndef && !Nl) {
    6134:     IS        fields;
    6135:     PetscInt *fld, nf;

    6137:     for (f = 0, nf = 0; f < Nf; ++f)
    6138:       if (!dm->fields[f].label) ++nf;
    6139:     PetscCheck(nf, comm, PETSC_ERR_PLIB, "All fields have labels, but we are trying to create a default DS");
    6140:     PetscCall(PetscMalloc1(nf, &fld));
    6141:     for (f = 0, nf = 0; f < Nf; ++f)
    6142:       if (!dm->fields[f].label) fld[nf++] = f;
    6143:     PetscCall(ISCreate(PETSC_COMM_SELF, &fields));
    6144:     PetscCall(PetscObjectSetOptionsPrefix((PetscObject)fields, "dm_fields_"));
    6145:     PetscCall(ISSetType(fields, ISGENERAL));
    6146:     PetscCall(ISGeneralSetIndices(fields, nf, fld, PETSC_OWN_POINTER));

    6148:     PetscCall(PetscDSCreate(PETSC_COMM_SELF, &dsDef));
    6149:     PetscCall(DMSetRegionDS(dm, NULL, fields, dsDef, NULL));
    6150:     PetscCall(PetscDSDestroy(&dsDef));
    6151:     PetscCall(ISDestroy(&fields));
    6152:   }
    6153:   PetscCall(DMGetRegionDS(dm, NULL, NULL, &dsDef, NULL));
    6154:   if (dsDef) PetscCall(PetscDSSetCoordinateDimension(dsDef, dE));
    6155:   /* Intersect labels with default fields */
    6156:   if (Ndef && Nl) {
    6157:     DM              plex;
    6158:     DMLabel         cellLabel;
    6159:     IS              fieldIS, allcellIS, defcellIS = NULL;
    6160:     PetscInt       *fields;
    6161:     const PetscInt *cells;
    6162:     PetscInt        depth, nf = 0, n, c;

    6164:     PetscCall(DMConvert(dm, DMPLEX, &plex));
    6165:     PetscCall(DMPlexGetDepth(plex, &depth));
    6166:     PetscCall(DMGetStratumIS(plex, "dim", depth, &allcellIS));
    6167:     if (!allcellIS) PetscCall(DMGetStratumIS(plex, "depth", depth, &allcellIS));
    6168:     /* TODO This looks like it only works for one label */
    6169:     for (l = 0; l < Nl; ++l) {
    6170:       DMLabel label = labelSet[l];
    6171:       IS      pointIS;

    6173:       PetscCall(ISDestroy(&defcellIS));
    6174:       PetscCall(DMLabelGetStratumIS(label, 1, &pointIS));
    6175:       PetscCall(ISDifference(allcellIS, pointIS, &defcellIS));
    6176:       PetscCall(ISDestroy(&pointIS));
    6177:     }
    6178:     PetscCall(ISDestroy(&allcellIS));

    6180:     PetscCall(DMLabelCreate(PETSC_COMM_SELF, "defaultCells", &cellLabel));
    6181:     PetscCall(ISGetLocalSize(defcellIS, &n));
    6182:     PetscCall(ISGetIndices(defcellIS, &cells));
    6183:     for (c = 0; c < n; ++c) PetscCall(DMLabelSetValue(cellLabel, cells[c], 1));
    6184:     PetscCall(ISRestoreIndices(defcellIS, &cells));
    6185:     PetscCall(ISDestroy(&defcellIS));
    6186:     PetscCall(DMPlexLabelComplete(plex, cellLabel));

    6188:     PetscCall(PetscMalloc1(Ndef, &fields));
    6189:     for (f = 0; f < Nf; ++f)
    6190:       if (!dm->fields[f].label) fields[nf++] = f;
    6191:     PetscCall(ISCreate(PETSC_COMM_SELF, &fieldIS));
    6192:     PetscCall(PetscObjectSetOptionsPrefix((PetscObject)fieldIS, "dm_fields_"));
    6193:     PetscCall(ISSetType(fieldIS, ISGENERAL));
    6194:     PetscCall(ISGeneralSetIndices(fieldIS, nf, fields, PETSC_OWN_POINTER));

    6196:     PetscCall(PetscDSCreate(PETSC_COMM_SELF, &dsDef));
    6197:     PetscCall(DMSetRegionDS(dm, cellLabel, fieldIS, dsDef, NULL));
    6198:     PetscCall(PetscDSSetCoordinateDimension(dsDef, dE));
    6199:     PetscCall(DMLabelDestroy(&cellLabel));
    6200:     PetscCall(PetscDSDestroy(&dsDef));
    6201:     PetscCall(ISDestroy(&fieldIS));
    6202:     PetscCall(DMDestroy(&plex));
    6203:   }
    6204:   /* Create label DSes
    6205:      - WE ONLY SUPPORT IDENTICAL OR DISJOINT LABELS
    6206:   */
    6207:   /* TODO Should check that labels are disjoint */
    6208:   for (l = 0; l < Nl; ++l) {
    6209:     DMLabel   label = labelSet[l];
    6210:     PetscDS   ds, dsIn = NULL;
    6211:     IS        fields;
    6212:     PetscInt *fld, nf;

    6214:     PetscCall(PetscDSCreate(PETSC_COMM_SELF, &ds));
    6215:     for (f = 0, nf = 0; f < Nf; ++f)
    6216:       if (label == dm->fields[f].label || !dm->fields[f].label) ++nf;
    6217:     PetscCall(PetscMalloc1(nf, &fld));
    6218:     for (f = 0, nf = 0; f < Nf; ++f)
    6219:       if (label == dm->fields[f].label || !dm->fields[f].label) fld[nf++] = f;
    6220:     PetscCall(ISCreate(PETSC_COMM_SELF, &fields));
    6221:     PetscCall(PetscObjectSetOptionsPrefix((PetscObject)fields, "dm_fields_"));
    6222:     PetscCall(ISSetType(fields, ISGENERAL));
    6223:     PetscCall(ISGeneralSetIndices(fields, nf, fld, PETSC_OWN_POINTER));
    6224:     PetscCall(PetscDSSetCoordinateDimension(ds, dE));
    6225:     {
    6226:       DMPolytopeType ct;
    6227:       PetscInt       lStart, lEnd;
    6228:       PetscBool      isCohesiveLocal = PETSC_FALSE, isCohesive;

    6230:       PetscCall(DMLabelGetBounds(label, &lStart, &lEnd));
    6231:       if (lStart >= 0) {
    6232:         PetscCall(DMPlexGetCellType(dm, lStart, &ct));
    6233:         switch (ct) {
    6234:         case DM_POLYTOPE_POINT_PRISM_TENSOR:
    6235:         case DM_POLYTOPE_SEG_PRISM_TENSOR:
    6236:         case DM_POLYTOPE_TRI_PRISM_TENSOR:
    6237:         case DM_POLYTOPE_QUAD_PRISM_TENSOR:
    6238:           isCohesiveLocal = PETSC_TRUE;
    6239:           break;
    6240:         default:
    6241:           break;
    6242:         }
    6243:       }
    6244:       PetscCallMPI(MPIU_Allreduce(&isCohesiveLocal, &isCohesive, 1, MPI_C_BOOL, MPI_LOR, comm));
    6245:       if (isCohesive) {
    6246:         PetscCall(PetscDSCreate(PETSC_COMM_SELF, &dsIn));
    6247:         PetscCall(PetscDSSetCoordinateDimension(dsIn, dE));
    6248:       }
    6249:       for (f = 0, nf = 0; f < Nf; ++f) {
    6250:         if (label == dm->fields[f].label || !dm->fields[f].label) {
    6251:           if (label == dm->fields[f].label) {
    6252:             PetscCall(PetscDSSetDiscretization(ds, nf, NULL));
    6253:             PetscCall(PetscDSSetCohesive(ds, nf, isCohesive));
    6254:             if (dsIn) {
    6255:               PetscCall(PetscDSSetDiscretization(dsIn, nf, NULL));
    6256:               PetscCall(PetscDSSetCohesive(dsIn, nf, isCohesive));
    6257:             }
    6258:           }
    6259:           ++nf;
    6260:         }
    6261:       }
    6262:     }
    6263:     PetscCall(DMSetRegionDS(dm, label, fields, ds, dsIn));
    6264:     PetscCall(ISDestroy(&fields));
    6265:     PetscCall(PetscDSDestroy(&ds));
    6266:     PetscCall(PetscDSDestroy(&dsIn));
    6267:   }
    6268:   PetscCall(PetscFree(labelSet));
    6269:   /* Set fields in DSes */
    6270:   for (s = 0; s < dm->Nds; ++s) {
    6271:     PetscDS         ds     = dm->probs[s].ds;
    6272:     PetscDS         dsIn   = dm->probs[s].dsIn;
    6273:     IS              fields = dm->probs[s].fields;
    6274:     const PetscInt *fld;
    6275:     PetscInt        nf, dsnf;
    6276:     PetscBool       isCohesive;

    6278:     PetscCall(PetscDSGetNumFields(ds, &dsnf));
    6279:     PetscCall(PetscDSIsCohesive(ds, &isCohesive));
    6280:     PetscCall(ISGetLocalSize(fields, &nf));
    6281:     PetscCall(ISGetIndices(fields, &fld));
    6282:     for (f = 0; f < nf; ++f) {
    6283:       PetscObject  disc = dm->fields[fld[f]].disc;
    6284:       PetscBool    isCohesiveField;
    6285:       PetscClassId id;

    6287:       /* Handle DS with no fields */
    6288:       if (dsnf) PetscCall(PetscDSGetCohesive(ds, f, &isCohesiveField));
    6289:       /* If this is a cohesive cell, then regular fields need the lower dimensional discretization */
    6290:       if (isCohesive) {
    6291:         if (!isCohesiveField) {
    6292:           PetscObject bdDisc;

    6294:           PetscCall(PetscFEGetHeightSubspace((PetscFE)disc, 1, (PetscFE *)&bdDisc));
    6295:           PetscCall(PetscDSSetDiscretization(ds, f, bdDisc));
    6296:           PetscCall(PetscDSSetDiscretization(dsIn, f, disc));
    6297:         } else {
    6298:           PetscCall(PetscDSSetDiscretization(ds, f, disc));
    6299:           PetscCall(PetscDSSetDiscretization(dsIn, f, disc));
    6300:         }
    6301:       } else {
    6302:         PetscCall(PetscDSSetDiscretization(ds, f, disc));
    6303:       }
    6304:       /* We allow people to have placeholder fields and construct the Section by hand */
    6305:       PetscCall(PetscObjectGetClassId(disc, &id));
    6306:       if ((id != PETSCFE_CLASSID) && (id != PETSCFV_CLASSID)) doSetup = PETSC_FALSE;
    6307:     }
    6308:     PetscCall(ISRestoreIndices(fields, &fld));
    6309:   }
    6310:   /* Allow k-jet tabulation */
    6311:   PetscCall(PetscOptionsGetInt(NULL, ((PetscObject)dm)->prefix, "-dm_ds_jet_degree", &k, &flg));
    6312:   if (flg) {
    6313:     for (s = 0; s < dm->Nds; ++s) {
    6314:       PetscDS  ds   = dm->probs[s].ds;
    6315:       PetscDS  dsIn = dm->probs[s].dsIn;
    6316:       PetscInt Nf, f;

    6318:       PetscCall(PetscDSGetNumFields(ds, &Nf));
    6319:       for (f = 0; f < Nf; ++f) {
    6320:         PetscCall(PetscDSSetJetDegree(ds, f, k));
    6321:         if (dsIn) PetscCall(PetscDSSetJetDegree(dsIn, f, k));
    6322:       }
    6323:     }
    6324:   }
    6325:   /* Setup DSes */
    6326:   if (doSetup) {
    6327:     for (s = 0; s < dm->Nds; ++s) {
    6328:       if (dm->setfromoptionscalled) {
    6329:         PetscCall(PetscDSSetFromOptions(dm->probs[s].ds));
    6330:         if (dm->probs[s].dsIn) PetscCall(PetscDSSetFromOptions(dm->probs[s].dsIn));
    6331:       }
    6332:       PetscCall(PetscDSSetUp(dm->probs[s].ds));
    6333:       if (dm->probs[s].dsIn) PetscCall(PetscDSSetUp(dm->probs[s].dsIn));
    6334:     }
    6335:   }
    6336:   PetscFunctionReturn(PETSC_SUCCESS);
    6337: }

    6339: /*@
    6340:   DMUseTensorOrder - Use a tensor product closure ordering for the default section

    6342:   Input Parameters:
    6343: + dm     - The DM
    6344: - tensor - Flag for tensor order

    6346:   Level: developer

    6348: .seealso: `DMPlexSetClosurePermutationTensor()`, `PetscSectionResetClosurePermutation()`
    6349: @*/
    6350: PetscErrorCode DMUseTensorOrder(DM dm, PetscBool tensor)
    6351: {
    6352:   PetscInt  Nf;
    6353:   PetscBool reorder = PETSC_TRUE, isPlex;

    6355:   PetscFunctionBegin;
    6356:   PetscCall(PetscObjectTypeCompare((PetscObject)dm, DMPLEX, &isPlex));
    6357:   PetscCall(DMGetNumFields(dm, &Nf));
    6358:   for (PetscInt f = 0; f < Nf; ++f) {
    6359:     PetscObject  obj;
    6360:     PetscClassId id;

    6362:     PetscCall(DMGetField(dm, f, NULL, &obj));
    6363:     PetscCall(PetscObjectGetClassId(obj, &id));
    6364:     if (id == PETSCFE_CLASSID) {
    6365:       PetscSpace sp;
    6366:       PetscBool  tensor;

    6368:       PetscCall(PetscFEGetBasisSpace((PetscFE)obj, &sp));
    6369:       PetscCall(PetscSpacePolynomialGetTensor(sp, &tensor));
    6370:       reorder = reorder && tensor ? PETSC_TRUE : PETSC_FALSE;
    6371:     } else reorder = PETSC_FALSE;
    6372:   }
    6373:   if (tensor) {
    6374:     if (reorder && isPlex) PetscCall(DMPlexSetClosurePermutationTensor(dm, PETSC_DETERMINE, NULL));
    6375:   } else {
    6376:     PetscSection s;

    6378:     PetscCall(DMGetLocalSection(dm, &s));
    6379:     if (s) PetscCall(PetscSectionResetClosurePermutation(s));
    6380:   }
    6381:   PetscFunctionReturn(PETSC_SUCCESS);
    6382: }

    6384: /*@
    6385:   DMComputeExactSolution - Compute the exact solution for a given `DM`, using the `PetscDS` information.

    6387:   Collective

    6389:   Input Parameters:
    6390: + dm   - The `DM`
    6391: - time - The time

    6393:   Output Parameters:
    6394: + u   - The vector will be filled with exact solution values, or `NULL`
    6395: - u_t - The vector will be filled with the time derivative of exact solution values, or `NULL`

    6397:   Level: developer

    6399:   Note:
    6400:   The user must call `PetscDSSetExactSolution()` before using this routine

    6402: .seealso: [](ch_dmbase), `DM`, `PetscDSSetExactSolution()`
    6403: @*/
    6404: PetscErrorCode DMComputeExactSolution(DM dm, PetscReal time, Vec u, Vec u_t)
    6405: {
    6406:   PetscErrorCode (**exacts)(PetscInt, PetscReal, const PetscReal x[], PetscInt, PetscScalar *u, PetscCtx ctx);
    6407:   void   **ectxs;
    6408:   Vec      locu, locu_t;
    6409:   PetscInt Nf, Nds, s;

    6411:   PetscFunctionBegin;
    6413:   if (u) {
    6415:     PetscCall(DMGetLocalVector(dm, &locu));
    6416:     PetscCall(VecSet(locu, 0.));
    6417:   }
    6418:   if (u_t) {
    6420:     PetscCall(DMGetLocalVector(dm, &locu_t));
    6421:     PetscCall(VecSet(locu_t, 0.));
    6422:   }
    6423:   PetscCall(DMGetNumFields(dm, &Nf));
    6424:   PetscCall(PetscMalloc2(Nf, &exacts, Nf, &ectxs));
    6425:   PetscCall(DMGetNumDS(dm, &Nds));
    6426:   for (s = 0; s < Nds; ++s) {
    6427:     PetscDS         ds;
    6428:     DMLabel         label;
    6429:     IS              fieldIS;
    6430:     const PetscInt *fields, id = 1;
    6431:     PetscInt        dsNf, f;

    6433:     PetscCall(DMGetRegionNumDS(dm, s, &label, &fieldIS, &ds, NULL));
    6434:     PetscCall(PetscDSGetNumFields(ds, &dsNf));
    6435:     PetscCall(ISGetIndices(fieldIS, &fields));
    6436:     PetscCall(PetscArrayzero(exacts, Nf));
    6437:     PetscCall(PetscArrayzero(ectxs, Nf));
    6438:     if (u) {
    6439:       for (f = 0; f < dsNf; ++f) PetscCall(PetscDSGetExactSolution(ds, fields[f], &exacts[fields[f]], &ectxs[fields[f]]));
    6440:       if (label) PetscCall(DMProjectFunctionLabelLocal(dm, time, label, 1, &id, 0, NULL, exacts, ectxs, INSERT_ALL_VALUES, locu));
    6441:       else PetscCall(DMProjectFunctionLocal(dm, time, exacts, ectxs, INSERT_ALL_VALUES, locu));
    6442:     }
    6443:     if (u_t) {
    6444:       PetscCall(PetscArrayzero(exacts, Nf));
    6445:       PetscCall(PetscArrayzero(ectxs, Nf));
    6446:       for (f = 0; f < dsNf; ++f) PetscCall(PetscDSGetExactSolutionTimeDerivative(ds, fields[f], &exacts[fields[f]], &ectxs[fields[f]]));
    6447:       if (label) PetscCall(DMProjectFunctionLabelLocal(dm, time, label, 1, &id, 0, NULL, exacts, ectxs, INSERT_ALL_VALUES, locu_t));
    6448:       else PetscCall(DMProjectFunctionLocal(dm, time, exacts, ectxs, INSERT_ALL_VALUES, locu_t));
    6449:     }
    6450:     PetscCall(ISRestoreIndices(fieldIS, &fields));
    6451:   }
    6452:   if (u) {
    6453:     PetscCall(PetscObjectSetName((PetscObject)u, "Exact Solution"));
    6454:     PetscCall(PetscObjectSetOptionsPrefix((PetscObject)u, "exact_"));
    6455:   }
    6456:   if (u_t) {
    6457:     PetscCall(PetscObjectSetName((PetscObject)u, "Exact Solution Time Derivative"));
    6458:     PetscCall(PetscObjectSetOptionsPrefix((PetscObject)u_t, "exact_t_"));
    6459:   }
    6460:   PetscCall(PetscFree2(exacts, ectxs));
    6461:   if (u) {
    6462:     PetscCall(DMLocalToGlobalBegin(dm, locu, INSERT_ALL_VALUES, u));
    6463:     PetscCall(DMLocalToGlobalEnd(dm, locu, INSERT_ALL_VALUES, u));
    6464:     PetscCall(DMRestoreLocalVector(dm, &locu));
    6465:   }
    6466:   if (u_t) {
    6467:     PetscCall(DMLocalToGlobalBegin(dm, locu_t, INSERT_ALL_VALUES, u_t));
    6468:     PetscCall(DMLocalToGlobalEnd(dm, locu_t, INSERT_ALL_VALUES, u_t));
    6469:     PetscCall(DMRestoreLocalVector(dm, &locu_t));
    6470:   }
    6471:   PetscFunctionReturn(PETSC_SUCCESS);
    6472: }

    6474: static PetscErrorCode DMTransferDS_Internal(DM dm, DMLabel label, IS fields, PetscInt minDegree, PetscInt maxDegree, PetscDS ds, PetscDS dsIn)
    6475: {
    6476:   PetscDS dsNew, dsInNew = NULL;

    6478:   PetscFunctionBegin;
    6479:   PetscCall(PetscDSCreate(PetscObjectComm((PetscObject)ds), &dsNew));
    6480:   PetscCall(PetscDSCopy(ds, minDegree, maxDegree, dm, dsNew));
    6481:   if (dsIn) {
    6482:     PetscCall(PetscDSCreate(PetscObjectComm((PetscObject)dsIn), &dsInNew));
    6483:     PetscCall(PetscDSCopy(dsIn, minDegree, maxDegree, dm, dsInNew));
    6484:   }
    6485:   PetscCall(DMSetRegionDS(dm, label, fields, dsNew, dsInNew));
    6486:   PetscCall(PetscDSDestroy(&dsNew));
    6487:   PetscCall(PetscDSDestroy(&dsInNew));
    6488:   PetscFunctionReturn(PETSC_SUCCESS);
    6489: }

    6491: /*@
    6492:   DMCopyDS - Copy the discrete systems for the `DM` into another `DM`

    6494:   Collective

    6496:   Input Parameters:
    6497: + dm        - The `DM`
    6498: . minDegree - Minimum degree for a discretization, or `PETSC_DETERMINE` for no limit
    6499: - maxDegree - Maximum degree for a discretization, or `PETSC_DETERMINE` for no limit

    6501:   Output Parameter:
    6502: . newdm - The `DM`

    6504:   Level: advanced

    6506: .seealso: [](ch_dmbase), `DM`, `DMCopyFields()`, `DMAddField()`, `DMGetDS()`, `DMGetCellDS()`, `DMGetRegionDS()`, `DMSetRegionDS()`
    6507: @*/
    6508: PetscErrorCode DMCopyDS(DM dm, PetscInt minDegree, PetscInt maxDegree, DM newdm)
    6509: {
    6510:   PetscInt Nds, s;

    6512:   PetscFunctionBegin;
    6513:   if (dm == newdm) PetscFunctionReturn(PETSC_SUCCESS);
    6514:   PetscCall(DMGetNumDS(dm, &Nds));
    6515:   PetscCall(DMClearDS(newdm));
    6516:   for (s = 0; s < Nds; ++s) {
    6517:     DMLabel  label;
    6518:     IS       fields;
    6519:     PetscDS  ds, dsIn, newds;
    6520:     PetscInt Nbd, bd;

    6522:     PetscCall(DMGetRegionNumDS(dm, s, &label, &fields, &ds, &dsIn));
    6523:     /* TODO: We need to change all keys from labels in the old DM to labels in the new DM */
    6524:     PetscCall(DMTransferDS_Internal(newdm, label, fields, minDegree, maxDegree, ds, dsIn));
    6525:     /* Complete new labels in the new DS */
    6526:     PetscCall(DMGetRegionDS(newdm, label, NULL, &newds, NULL));
    6527:     PetscCall(PetscDSGetNumBoundary(newds, &Nbd));
    6528:     for (bd = 0; bd < Nbd; ++bd) {
    6529:       PetscWeakForm wf;
    6530:       DMLabel       label;
    6531:       PetscInt      field;

    6533:       PetscCall(PetscDSGetBoundary(newds, bd, &wf, NULL, NULL, &label, NULL, NULL, &field, NULL, NULL, NULL, NULL, NULL));
    6534:       PetscCall(PetscWeakFormReplaceLabel(wf, label));
    6535:     }
    6536:   }
    6537:   PetscCall(DMCompleteBCLabels_Internal(newdm));
    6538:   PetscFunctionReturn(PETSC_SUCCESS);
    6539: }

    6541: /*@
    6542:   DMCopyDisc - Copy the fields and discrete systems for the `DM` into another `DM`

    6544:   Collective

    6546:   Input Parameter:
    6547: . dm - The `DM`

    6549:   Output Parameter:
    6550: . newdm - The `DM`

    6552:   Level: advanced

    6554:   Developer Note:
    6555:   Really ugly name, nothing in PETSc is called a `Disc` plus it is an ugly abbreviation

    6557: .seealso: [](ch_dmbase), `DM`, `DMCopyFields()`, `DMCopyDS()`
    6558: @*/
    6559: PetscErrorCode DMCopyDisc(DM dm, DM newdm)
    6560: {
    6561:   PetscFunctionBegin;
    6562:   PetscCall(DMCopyFields(dm, PETSC_DETERMINE, PETSC_DETERMINE, newdm));
    6563:   PetscCall(DMCopyDS(dm, PETSC_DETERMINE, PETSC_DETERMINE, newdm));
    6564:   PetscFunctionReturn(PETSC_SUCCESS);
    6565: }

    6567: /*@
    6568:   DMGetDimension - Return the topological dimension of the `DM`

    6570:   Not Collective

    6572:   Input Parameter:
    6573: . dm - The `DM`

    6575:   Output Parameter:
    6576: . dim - The topological dimension

    6578:   Level: beginner

    6580: .seealso: [](ch_dmbase), `DM`, `DMSetDimension()`, `DMCreate()`
    6581: @*/
    6582: PetscErrorCode DMGetDimension(DM dm, PetscInt *dim)
    6583: {
    6584:   PetscFunctionBegin;
    6586:   PetscAssertPointer(dim, 2);
    6587:   *dim = dm->dim;
    6588:   PetscFunctionReturn(PETSC_SUCCESS);
    6589: }

    6591: /*@
    6592:   DMSetDimension - Set the topological dimension of the `DM`

    6594:   Collective

    6596:   Input Parameters:
    6597: + dm  - The `DM`
    6598: - dim - The topological dimension

    6600:   Level: beginner

    6602: .seealso: [](ch_dmbase), `DM`, `DMGetDimension()`, `DMCreate()`
    6603: @*/
    6604: PetscErrorCode DMSetDimension(DM dm, PetscInt dim)
    6605: {
    6606:   PetscDS  ds;
    6607:   PetscInt Nds, n;

    6609:   PetscFunctionBegin;
    6612:   if (dm->dim != dim) PetscCall(DMSetPeriodicity(dm, NULL, NULL, NULL));
    6613:   dm->dim = dim;
    6614:   if (dm->dim >= 0) {
    6615:     PetscCall(DMGetNumDS(dm, &Nds));
    6616:     for (n = 0; n < Nds; ++n) {
    6617:       PetscCall(DMGetRegionNumDS(dm, n, NULL, NULL, &ds, NULL));
    6618:       if (ds->dimEmbed < 0) PetscCall(PetscDSSetCoordinateDimension(ds, dim));
    6619:     }
    6620:   }
    6621:   PetscFunctionReturn(PETSC_SUCCESS);
    6622: }

    6624: /*@
    6625:   DMGetDimPoints - Get the half-open interval for all points of a given dimension

    6627:   Collective

    6629:   Input Parameters:
    6630: + dm  - the `DM`
    6631: - dim - the dimension

    6633:   Output Parameters:
    6634: + pStart - The first point of the given dimension
    6635: - pEnd   - The first point following points of the given dimension

    6637:   Level: intermediate

    6639:   Note:
    6640:   The points are vertices in the Hasse diagram encoding the topology. This is explained in
    6641:   https://arxiv.org/abs/0908.4427. If no points exist of this dimension in the storage scheme,
    6642:   then the interval is empty.

    6644: .seealso: [](ch_dmbase), `DM`, `DMPLEX`, `DMPlexGetDepthStratum()`, `DMPlexGetHeightStratum()`
    6645: @*/
    6646: PetscErrorCode DMGetDimPoints(DM dm, PetscInt dim, PetscInt *pStart, PetscInt *pEnd)
    6647: {
    6648:   PetscInt d;

    6650:   PetscFunctionBegin;
    6652:   PetscCall(DMGetDimension(dm, &d));
    6653:   PetscCheck((dim >= 0) && (dim <= d), PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_OUTOFRANGE, "Invalid dimension %" PetscInt_FMT, dim);
    6654:   PetscUseTypeMethod(dm, getdimpoints, dim, pStart, pEnd);
    6655:   PetscFunctionReturn(PETSC_SUCCESS);
    6656: }

    6658: /*@
    6659:   DMGetOutputDM - Retrieve the `DM` associated with the layout for output

    6661:   Collective

    6663:   Input Parameter:
    6664: . dm - The original `DM`

    6666:   Output Parameter:
    6667: . odm - The `DM` which provides the layout for output

    6669:   Level: intermediate

    6671:   Note:
    6672:   In some situations the vector obtained with `DMCreateGlobalVector()` excludes points for degrees of freedom that are associated with fixed (Dirichelet) boundary
    6673:   conditions since the algebraic solver does not solve for those variables. The output `DM` includes these excluded points and its global vector contains the
    6674:   locations for those dof so that they can be output to a file or other viewer along with the unconstrained dof.

    6676: .seealso: [](ch_dmbase), `DM`, `VecView()`, `DMGetGlobalSection()`, `DMCreateGlobalVector()`, `PetscSectionHasConstraints()`, `DMSetGlobalSection()`
    6677: @*/
    6678: PetscErrorCode DMGetOutputDM(DM dm, DM *odm)
    6679: {
    6680:   PetscSection section;
    6681:   IS           perm;
    6682:   PetscBool    hasConstraints, newDM, gnewDM;
    6683:   PetscInt     num_face_sfs = 0;

    6685:   PetscFunctionBegin;
    6687:   PetscAssertPointer(odm, 2);
    6688:   PetscCall(DMGetLocalSection(dm, &section));
    6689:   PetscCall(PetscSectionHasConstraints(section, &hasConstraints));
    6690:   PetscCall(PetscSectionGetPermutation(section, &perm));
    6691:   PetscCall(DMPlexGetIsoperiodicFaceSF(dm, &num_face_sfs, NULL));
    6692:   newDM = hasConstraints || perm || (num_face_sfs > 0) ? PETSC_TRUE : PETSC_FALSE;
    6693:   PetscCallMPI(MPIU_Allreduce(&newDM, &gnewDM, 1, MPI_C_BOOL, MPI_LOR, PetscObjectComm((PetscObject)dm)));
    6694:   if (!gnewDM) {
    6695:     *odm = dm;
    6696:     PetscFunctionReturn(PETSC_SUCCESS);
    6697:   }
    6698:   if (!dm->dmBC) {
    6699:     PetscSection newSection, gsection;
    6700:     PetscSF      sf, sfNatural;
    6701:     PetscBool    usePerm = dm->ignorePermOutput ? PETSC_FALSE : PETSC_TRUE;

    6703:     PetscCall(DMClone(dm, &dm->dmBC));
    6704:     PetscCall(DMCopyDisc(dm, dm->dmBC));
    6705:     PetscCall(PetscSectionClone(section, &newSection));
    6706:     PetscCall(DMSetLocalSection(dm->dmBC, newSection));
    6707:     PetscCall(PetscSectionDestroy(&newSection));
    6708:     PetscCall(DMGetNaturalSF(dm, &sfNatural));
    6709:     PetscCall(DMSetNaturalSF(dm->dmBC, sfNatural));
    6710:     PetscCall(DMGetPointSF(dm->dmBC, &sf));
    6711:     PetscCall(PetscSectionCreateGlobalSection(section, sf, usePerm, PETSC_TRUE, PETSC_FALSE, &gsection));
    6712:     PetscCall(DMSetGlobalSection(dm->dmBC, gsection));
    6713:     PetscCall(PetscSectionDestroy(&gsection));
    6714:   }
    6715:   *odm = dm->dmBC;
    6716:   PetscFunctionReturn(PETSC_SUCCESS);
    6717: }

    6719: /*@
    6720:   DMGetOutputSequenceNumber - Retrieve the sequence number/value for output

    6722:   Input Parameter:
    6723: . dm - The original `DM`

    6725:   Output Parameters:
    6726: + num - The output sequence number
    6727: - val - The output sequence value

    6729:   Level: intermediate

    6731:   Note:
    6732:   This is intended for output that should appear in sequence, for instance
    6733:   a set of timesteps in an `PETSCVIEWERHDF5` file, or a set of realizations of a stochastic system.

    6735:   Developer Note:
    6736:   The `DM` serves as a convenient place to store the current iteration value. The iteration is not
    6737:   not directly related to the `DM`.

    6739: .seealso: [](ch_dmbase), `DM`, `VecView()`
    6740: @*/
    6741: PetscErrorCode DMGetOutputSequenceNumber(DM dm, PetscInt *num, PetscReal *val)
    6742: {
    6743:   PetscFunctionBegin;
    6745:   if (num) {
    6746:     PetscAssertPointer(num, 2);
    6747:     *num = dm->outputSequenceNum;
    6748:   }
    6749:   if (val) {
    6750:     PetscAssertPointer(val, 3);
    6751:     *val = dm->outputSequenceVal;
    6752:   }
    6753:   PetscFunctionReturn(PETSC_SUCCESS);
    6754: }

    6756: /*@
    6757:   DMSetOutputSequenceNumber - Set the sequence number/value for output

    6759:   Input Parameters:
    6760: + dm  - The original `DM`
    6761: . num - The output sequence number
    6762: - val - The output sequence value

    6764:   Level: intermediate

    6766:   Note:
    6767:   This is intended for output that should appear in sequence, for instance
    6768:   a set of timesteps in an `PETSCVIEWERHDF5` file, or a set of realizations of a stochastic system.

    6770: .seealso: [](ch_dmbase), `DM`, `VecView()`
    6771: @*/
    6772: PetscErrorCode DMSetOutputSequenceNumber(DM dm, PetscInt num, PetscReal val)
    6773: {
    6774:   PetscFunctionBegin;
    6776:   dm->outputSequenceNum = num;
    6777:   dm->outputSequenceVal = val;
    6778:   PetscFunctionReturn(PETSC_SUCCESS);
    6779: }

    6781: /*@
    6782:   DMOutputSequenceLoad - Retrieve the sequence value from a `PetscViewer`

    6784:   Input Parameters:
    6785: + dm     - The original `DM`
    6786: . viewer - The `PetscViewer` to get it from
    6787: . name   - The sequence name
    6788: - num    - The output sequence number

    6790:   Output Parameter:
    6791: . val - The output sequence value

    6793:   Level: intermediate

    6795:   Note:
    6796:   This is intended for output that should appear in sequence, for instance
    6797:   a set of timesteps in an `PETSCVIEWERHDF5` file, or a set of realizations of a stochastic system.

    6799:   Developer Note:
    6800:   It is unclear at the user API level why a `DM` is needed as input

    6802: .seealso: [](ch_dmbase), `DM`, `DMGetOutputSequenceNumber()`, `DMSetOutputSequenceNumber()`, `VecView()`
    6803: @*/
    6804: PetscErrorCode DMOutputSequenceLoad(DM dm, PetscViewer viewer, const char name[], PetscInt num, PetscReal *val)
    6805: {
    6806:   PetscBool ishdf5;

    6808:   PetscFunctionBegin;
    6811:   PetscAssertPointer(name, 3);
    6812:   PetscAssertPointer(val, 5);
    6813:   PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERHDF5, &ishdf5));
    6814:   PetscCheck(ishdf5, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Invalid viewer; open viewer with PetscViewerHDF5Open()");
    6815: #if defined(PETSC_HAVE_HDF5)
    6816:   PetscScalar value;

    6818:   PetscCall(DMSequenceLoad_HDF5_Internal(dm, name, num, &value, viewer));
    6819:   *val = PetscRealPart(value);
    6820: #endif
    6821:   PetscFunctionReturn(PETSC_SUCCESS);
    6822: }

    6824: /*@
    6825:   DMGetOutputSequenceLength - Retrieve the number of sequence values from a `PetscViewer`

    6827:   Input Parameters:
    6828: + dm     - The original `DM`
    6829: . viewer - The `PetscViewer` to get it from
    6830: - name   - The sequence name

    6832:   Output Parameter:
    6833: . len - The length of the output sequence

    6835:   Level: intermediate

    6837:   Note:
    6838:   This is intended for output that should appear in sequence, for instance
    6839:   a set of timesteps in an `PETSCVIEWERHDF5` file, or a set of realizations of a stochastic system.

    6841:   Developer Note:
    6842:   It is unclear at the user API level why a `DM` is needed as input

    6844: .seealso: [](ch_dmbase), `DM`, `DMGetOutputSequenceNumber()`, `DMSetOutputSequenceNumber()`, `VecView()`
    6845: @*/
    6846: PetscErrorCode DMGetOutputSequenceLength(DM dm, PetscViewer viewer, const char name[], PetscInt *len)
    6847: {
    6848:   PetscBool ishdf5;

    6850:   PetscFunctionBegin;
    6853:   PetscAssertPointer(name, 3);
    6854:   PetscAssertPointer(len, 4);
    6855:   PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERHDF5, &ishdf5));
    6856:   PetscCheck(ishdf5, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Invalid viewer; open viewer with PetscViewerHDF5Open()");
    6857: #if defined(PETSC_HAVE_HDF5)
    6858:   PetscCall(DMSequenceGetLength_HDF5_Internal(dm, name, len, viewer));
    6859: #endif
    6860:   PetscFunctionReturn(PETSC_SUCCESS);
    6861: }

    6863: /*@
    6864:   DMGetUseNatural - Get the flag for creating a mapping to the natural order when a `DM` is (re)distributed in parallel

    6866:   Not Collective

    6868:   Input Parameter:
    6869: . dm - The `DM`

    6871:   Output Parameter:
    6872: . useNatural - `PETSC_TRUE` to build the mapping to a natural order during distribution

    6874:   Level: beginner

    6876: .seealso: [](ch_dmbase), `DM`, `DMSetUseNatural()`, `DMCreate()`
    6877: @*/
    6878: PetscErrorCode DMGetUseNatural(DM dm, PetscBool *useNatural)
    6879: {
    6880:   PetscFunctionBegin;
    6882:   PetscAssertPointer(useNatural, 2);
    6883:   *useNatural = dm->useNatural;
    6884:   PetscFunctionReturn(PETSC_SUCCESS);
    6885: }

    6887: /*@
    6888:   DMSetUseNatural - Set the flag for creating a mapping to the natural order when a `DM` is (re)distributed in parallel

    6890:   Collective

    6892:   Input Parameters:
    6893: + dm         - The `DM`
    6894: - useNatural - `PETSC_TRUE` to build the mapping to a natural order during distribution

    6896:   Level: beginner

    6898:   Note:
    6899:   This also causes the map to be build after `DMCreateSubDM()` and `DMCreateSuperDM()`

    6901: .seealso: [](ch_dmbase), `DM`, `DMGetUseNatural()`, `DMCreate()`, `DMPlexDistribute()`, `DMCreateSubDM()`, `DMCreateSuperDM()`
    6902: @*/
    6903: PetscErrorCode DMSetUseNatural(DM dm, PetscBool useNatural)
    6904: {
    6905:   PetscFunctionBegin;
    6908:   dm->useNatural = useNatural;
    6909:   PetscFunctionReturn(PETSC_SUCCESS);
    6910: }

    6912: /*@
    6913:   DMCreateLabel - Create a label of the given name if it does not already exist in the `DM`

    6915:   Not Collective

    6917:   Input Parameters:
    6918: + dm   - The `DM` object
    6919: - name - The label name

    6921:   Level: intermediate

    6923: .seealso: [](ch_dmbase), `DM`, `DMLabelCreate()`, `DMHasLabel()`, `DMGetLabelValue()`, `DMSetLabelValue()`, `DMGetStratumIS()`
    6924: @*/
    6925: PetscErrorCode DMCreateLabel(DM dm, const char name[])
    6926: {
    6927:   PetscBool flg;
    6928:   DMLabel   label;

    6930:   PetscFunctionBegin;
    6932:   PetscAssertPointer(name, 2);
    6933:   PetscCall(DMHasLabel(dm, name, &flg));
    6934:   if (!flg) {
    6935:     PetscCall(DMLabelCreate(PETSC_COMM_SELF, name, &label));
    6936:     PetscCall(DMAddLabel(dm, label));
    6937:     PetscCall(DMLabelDestroy(&label));
    6938:   }
    6939:   PetscFunctionReturn(PETSC_SUCCESS);
    6940: }

    6942: /*@
    6943:   DMCreateLabelAtIndex - Create a label of the given name at the given index. If it already exists in the `DM`, move it to this index.

    6945:   Not Collective

    6947:   Input Parameters:
    6948: + dm   - The `DM` object
    6949: . l    - The index for the label
    6950: - name - The label name

    6952:   Level: intermediate

    6954: .seealso: [](ch_dmbase), `DM`, `DMCreateLabel()`, `DMLabelCreate()`, `DMHasLabel()`, `DMGetLabelValue()`, `DMSetLabelValue()`, `DMGetStratumIS()`
    6955: @*/
    6956: PetscErrorCode DMCreateLabelAtIndex(DM dm, PetscInt l, const char name[])
    6957: {
    6958:   DMLabelLink orig, prev = NULL;
    6959:   DMLabel     label;
    6960:   PetscInt    Nl, m;
    6961:   PetscBool   flg, match;
    6962:   const char *lname;

    6964:   PetscFunctionBegin;
    6966:   PetscAssertPointer(name, 3);
    6967:   PetscCall(DMHasLabel(dm, name, &flg));
    6968:   if (!flg) {
    6969:     PetscCall(DMLabelCreate(PETSC_COMM_SELF, name, &label));
    6970:     PetscCall(DMAddLabel(dm, label));
    6971:     PetscCall(DMLabelDestroy(&label));
    6972:   }
    6973:   PetscCall(DMGetNumLabels(dm, &Nl));
    6974:   PetscCheck(l < Nl, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Label index %" PetscInt_FMT " must be in [0, %" PetscInt_FMT ")", l, Nl);
    6975:   for (m = 0, orig = dm->labels; m < Nl; ++m, prev = orig, orig = orig->next) {
    6976:     PetscCall(PetscObjectGetName((PetscObject)orig->label, &lname));
    6977:     PetscCall(PetscStrcmp(name, lname, &match));
    6978:     if (match) break;
    6979:   }
    6980:   if (m == l) PetscFunctionReturn(PETSC_SUCCESS);
    6981:   if (!m) dm->labels = orig->next;
    6982:   else prev->next = orig->next;
    6983:   if (!l) {
    6984:     orig->next = dm->labels;
    6985:     dm->labels = orig;
    6986:   } else {
    6987:     for (m = 0, prev = dm->labels; m < l - 1; ++m, prev = prev->next);
    6988:     orig->next = prev->next;
    6989:     prev->next = orig;
    6990:   }
    6991:   PetscFunctionReturn(PETSC_SUCCESS);
    6992: }

    6994: /*@
    6995:   DMGetLabelValue - Get the value in a `DMLabel` for the given point, with -1 as the default

    6997:   Not Collective

    6999:   Input Parameters:
    7000: + dm    - The `DM` object
    7001: . name  - The label name
    7002: - point - The mesh point

    7004:   Output Parameter:
    7005: . value - The label value for this point, or -1 if the point is not in the label

    7007:   Level: beginner

    7009: .seealso: [](ch_dmbase), `DM`, `DMLabelGetValue()`, `DMSetLabelValue()`, `DMGetStratumIS()`
    7010: @*/
    7011: PetscErrorCode DMGetLabelValue(DM dm, const char name[], PetscInt point, PetscInt *value)
    7012: {
    7013:   DMLabel label;

    7015:   PetscFunctionBegin;
    7017:   PetscAssertPointer(name, 2);
    7018:   PetscCall(DMGetLabel(dm, name, &label));
    7019:   PetscCheck(label, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "No label named %s was found", name);
    7020:   PetscCall(DMLabelGetValue(label, point, value));
    7021:   PetscFunctionReturn(PETSC_SUCCESS);
    7022: }

    7024: /*@
    7025:   DMSetLabelValue - Add a point to a `DMLabel` with given value

    7027:   Not Collective

    7029:   Input Parameters:
    7030: + dm    - The `DM` object
    7031: . name  - The label name
    7032: . point - The mesh point
    7033: - value - The label value for this point

    7035:   Output Parameter:

    7037:   Level: beginner

    7039: .seealso: [](ch_dmbase), `DM`, `DMLabelSetValue()`, `DMGetStratumIS()`, `DMClearLabelValue()`
    7040: @*/
    7041: PetscErrorCode DMSetLabelValue(DM dm, const char name[], PetscInt point, PetscInt value)
    7042: {
    7043:   DMLabel label;

    7045:   PetscFunctionBegin;
    7047:   PetscAssertPointer(name, 2);
    7048:   PetscCall(DMGetLabel(dm, name, &label));
    7049:   if (!label) {
    7050:     PetscCall(DMCreateLabel(dm, name));
    7051:     PetscCall(DMGetLabel(dm, name, &label));
    7052:   }
    7053:   PetscCall(DMLabelSetValue(label, point, value));
    7054:   PetscFunctionReturn(PETSC_SUCCESS);
    7055: }

    7057: /*@
    7058:   DMClearLabelValue - Remove a point from a `DMLabel` with given value

    7060:   Not Collective

    7062:   Input Parameters:
    7063: + dm    - The `DM` object
    7064: . name  - The label name
    7065: . point - The mesh point
    7066: - value - The label value for this point

    7068:   Level: beginner

    7070: .seealso: [](ch_dmbase), `DM`, `DMLabelClearValue()`, `DMSetLabelValue()`, `DMGetStratumIS()`
    7071: @*/
    7072: PetscErrorCode DMClearLabelValue(DM dm, const char name[], PetscInt point, PetscInt value)
    7073: {
    7074:   DMLabel label;

    7076:   PetscFunctionBegin;
    7078:   PetscAssertPointer(name, 2);
    7079:   PetscCall(DMGetLabel(dm, name, &label));
    7080:   if (!label) PetscFunctionReturn(PETSC_SUCCESS);
    7081:   PetscCall(DMLabelClearValue(label, point, value));
    7082:   PetscFunctionReturn(PETSC_SUCCESS);
    7083: }

    7085: /*@
    7086:   DMGetLabelSize - Get the value of `DMLabelGetNumValues()` of a `DMLabel` in the `DM`

    7088:   Not Collective

    7090:   Input Parameters:
    7091: + dm   - The `DM` object
    7092: - name - The label name

    7094:   Output Parameter:
    7095: . size - The number of different integer ids, or 0 if the label does not exist

    7097:   Level: beginner

    7099:   Developer Note:
    7100:   This should be renamed to something like `DMGetLabelNumValues()` or removed.

    7102: .seealso: [](ch_dmbase), `DM`, `DMLabelGetNumValues()`, `DMSetLabelValue()`, `DMGetLabel()`
    7103: @*/
    7104: PetscErrorCode DMGetLabelSize(DM dm, const char name[], PetscInt *size)
    7105: {
    7106:   DMLabel label;

    7108:   PetscFunctionBegin;
    7110:   PetscAssertPointer(name, 2);
    7111:   PetscAssertPointer(size, 3);
    7112:   PetscCall(DMGetLabel(dm, name, &label));
    7113:   *size = 0;
    7114:   if (!label) PetscFunctionReturn(PETSC_SUCCESS);
    7115:   PetscCall(DMLabelGetNumValues(label, size));
    7116:   PetscFunctionReturn(PETSC_SUCCESS);
    7117: }

    7119: /*@
    7120:   DMGetLabelIdIS - Get the `DMLabelGetValueIS()` from a `DMLabel` in the `DM`

    7122:   Not Collective

    7124:   Input Parameters:
    7125: + dm   - The `DM` object
    7126: - name - The label name

    7128:   Output Parameter:
    7129: . ids - The integer ids, or `NULL` if the label does not exist

    7131:   Level: beginner

    7133: .seealso: [](ch_dmbase), `DM`, `DMLabelGetValueIS()`, `DMGetLabelSize()`
    7134: @*/
    7135: PetscErrorCode DMGetLabelIdIS(DM dm, const char name[], IS *ids)
    7136: {
    7137:   DMLabel label;

    7139:   PetscFunctionBegin;
    7141:   PetscAssertPointer(name, 2);
    7142:   PetscAssertPointer(ids, 3);
    7143:   PetscCall(DMGetLabel(dm, name, &label));
    7144:   *ids = NULL;
    7145:   if (label) PetscCall(DMLabelGetValueIS(label, ids));
    7146:   else {
    7147:     /* returning an empty IS */
    7148:     PetscCall(ISCreateGeneral(PETSC_COMM_SELF, 0, NULL, PETSC_USE_POINTER, ids));
    7149:   }
    7150:   PetscFunctionReturn(PETSC_SUCCESS);
    7151: }

    7153: /*@
    7154:   DMGetStratumSize - Get the number of points in a label stratum

    7156:   Not Collective

    7158:   Input Parameters:
    7159: + dm    - The `DM` object
    7160: . name  - The label name of the stratum
    7161: - value - The stratum value

    7163:   Output Parameter:
    7164: . size - The number of points, also called the stratum size

    7166:   Level: beginner

    7168: .seealso: [](ch_dmbase), `DM`, `DMLabelGetStratumSize()`, `DMGetLabelSize()`, `DMGetLabelIds()`
    7169: @*/
    7170: PetscErrorCode DMGetStratumSize(DM dm, const char name[], PetscInt value, PetscInt *size)
    7171: {
    7172:   DMLabel label;

    7174:   PetscFunctionBegin;
    7176:   PetscAssertPointer(name, 2);
    7177:   PetscAssertPointer(size, 4);
    7178:   PetscCall(DMGetLabel(dm, name, &label));
    7179:   *size = 0;
    7180:   if (!label) PetscFunctionReturn(PETSC_SUCCESS);
    7181:   PetscCall(DMLabelGetStratumSize(label, value, size));
    7182:   PetscFunctionReturn(PETSC_SUCCESS);
    7183: }

    7185: /*@
    7186:   DMGetStratumIS - Get the points in a label stratum

    7188:   Not Collective

    7190:   Input Parameters:
    7191: + dm    - The `DM` object
    7192: . name  - The label name
    7193: - value - The stratum value

    7195:   Output Parameter:
    7196: . points - The stratum points, or `NULL` if the label does not exist or does not have that value

    7198:   Level: beginner

    7200: .seealso: [](ch_dmbase), `DM`, `DMLabelGetStratumIS()`, `DMGetStratumSize()`
    7201: @*/
    7202: PetscErrorCode DMGetStratumIS(DM dm, const char name[], PetscInt value, IS *points)
    7203: {
    7204:   DMLabel label;

    7206:   PetscFunctionBegin;
    7208:   PetscAssertPointer(name, 2);
    7209:   PetscAssertPointer(points, 4);
    7210:   PetscCall(DMGetLabel(dm, name, &label));
    7211:   *points = NULL;
    7212:   if (!label) PetscFunctionReturn(PETSC_SUCCESS);
    7213:   PetscCall(DMLabelGetStratumIS(label, value, points));
    7214:   PetscFunctionReturn(PETSC_SUCCESS);
    7215: }

    7217: /*@
    7218:   DMSetStratumIS - Set the points in a label stratum

    7220:   Not Collective

    7222:   Input Parameters:
    7223: + dm     - The `DM` object
    7224: . name   - The label name
    7225: . value  - The stratum value
    7226: - points - The stratum points

    7228:   Level: beginner

    7230: .seealso: [](ch_dmbase), `DM`, `DMLabel`, `DMClearLabelStratum()`, `DMLabelClearStratum()`, `DMLabelSetStratumIS()`, `DMGetStratumSize()`
    7231: @*/
    7232: PetscErrorCode DMSetStratumIS(DM dm, const char name[], PetscInt value, IS points)
    7233: {
    7234:   DMLabel label;

    7236:   PetscFunctionBegin;
    7238:   PetscAssertPointer(name, 2);
    7240:   PetscCall(DMGetLabel(dm, name, &label));
    7241:   if (!label) PetscFunctionReturn(PETSC_SUCCESS);
    7242:   PetscCall(DMLabelSetStratumIS(label, value, points));
    7243:   PetscFunctionReturn(PETSC_SUCCESS);
    7244: }

    7246: /*@
    7247:   DMClearLabelStratum - Remove all points from a stratum from a `DMLabel`

    7249:   Not Collective

    7251:   Input Parameters:
    7252: + dm    - The `DM` object
    7253: . name  - The label name
    7254: - value - The label value for this point

    7256:   Output Parameter:

    7258:   Level: beginner

    7260: .seealso: [](ch_dmbase), `DM`, `DMLabel`, `DMLabelClearStratum()`, `DMSetLabelValue()`, `DMGetStratumIS()`, `DMClearLabelValue()`
    7261: @*/
    7262: PetscErrorCode DMClearLabelStratum(DM dm, const char name[], PetscInt value)
    7263: {
    7264:   DMLabel label;

    7266:   PetscFunctionBegin;
    7268:   PetscAssertPointer(name, 2);
    7269:   PetscCall(DMGetLabel(dm, name, &label));
    7270:   if (!label) PetscFunctionReturn(PETSC_SUCCESS);
    7271:   PetscCall(DMLabelClearStratum(label, value));
    7272:   PetscFunctionReturn(PETSC_SUCCESS);
    7273: }

    7275: /*@
    7276:   DMGetNumLabels - Return the number of labels defined by on the `DM`

    7278:   Not Collective

    7280:   Input Parameter:
    7281: . dm - The `DM` object

    7283:   Output Parameter:
    7284: . numLabels - the number of Labels

    7286:   Level: intermediate

    7288: .seealso: [](ch_dmbase), `DM`, `DMLabel`, `DMGetLabelByNum()`, `DMGetLabelName()`, `DMGetLabelValue()`, `DMSetLabelValue()`, `DMGetStratumIS()`
    7289: @*/
    7290: PetscErrorCode DMGetNumLabels(DM dm, PetscInt *numLabels)
    7291: {
    7292:   DMLabelLink next = dm->labels;
    7293:   PetscInt    n    = 0;

    7295:   PetscFunctionBegin;
    7297:   PetscAssertPointer(numLabels, 2);
    7298:   while (next) {
    7299:     ++n;
    7300:     next = next->next;
    7301:   }
    7302:   *numLabels = n;
    7303:   PetscFunctionReturn(PETSC_SUCCESS);
    7304: }

    7306: /*@
    7307:   DMGetLabelName - Return the name of nth label

    7309:   Not Collective

    7311:   Input Parameters:
    7312: + dm - The `DM` object
    7313: - n  - the label number

    7315:   Output Parameter:
    7316: . name - the label name

    7318:   Level: intermediate

    7320:   Developer Note:
    7321:   Some of the functions that appropriate on labels using their number have the suffix ByNum, others do not.

    7323: .seealso: [](ch_dmbase), `DM`, `DMLabel`, `DMGetLabelByNum()`, `DMGetLabel()`, `DMGetLabelValue()`, `DMSetLabelValue()`, `DMGetStratumIS()`
    7324: @*/
    7325: PetscErrorCode DMGetLabelName(DM dm, PetscInt n, const char *name[])
    7326: {
    7327:   DMLabelLink next = dm->labels;
    7328:   PetscInt    l    = 0;

    7330:   PetscFunctionBegin;
    7332:   PetscAssertPointer(name, 3);
    7333:   while (next) {
    7334:     if (l == n) {
    7335:       PetscCall(PetscObjectGetName((PetscObject)next->label, name));
    7336:       PetscFunctionReturn(PETSC_SUCCESS);
    7337:     }
    7338:     ++l;
    7339:     next = next->next;
    7340:   }
    7341:   SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Label %" PetscInt_FMT " does not exist in this DM", n);
    7342: }

    7344: /*@
    7345:   DMHasLabel - Determine whether the `DM` has a label of a given name

    7347:   Not Collective

    7349:   Input Parameters:
    7350: + dm   - The `DM` object
    7351: - name - The label name

    7353:   Output Parameter:
    7354: . hasLabel - `PETSC_TRUE` if the label is present

    7356:   Level: intermediate

    7358: .seealso: [](ch_dmbase), `DM`, `DMLabel`, `DMGetLabel()`, `DMGetLabelByNum()`, `DMCreateLabel()`, `DMGetLabelValue()`, `DMSetLabelValue()`, `DMGetStratumIS()`
    7359: @*/
    7360: PetscErrorCode DMHasLabel(DM dm, const char name[], PetscBool *hasLabel)
    7361: {
    7362:   DMLabelLink next = dm->labels;
    7363:   const char *lname;

    7365:   PetscFunctionBegin;
    7367:   PetscAssertPointer(name, 2);
    7368:   PetscAssertPointer(hasLabel, 3);
    7369:   *hasLabel = PETSC_FALSE;
    7370:   while (next) {
    7371:     PetscCall(PetscObjectGetName((PetscObject)next->label, &lname));
    7372:     PetscCall(PetscStrcmp(name, lname, hasLabel));
    7373:     if (*hasLabel) break;
    7374:     next = next->next;
    7375:   }
    7376:   PetscFunctionReturn(PETSC_SUCCESS);
    7377: }

    7379: // PetscClangLinter pragma ignore: -fdoc-section-header-unknown
    7380: /*@
    7381:   DMGetLabel - Return the label of a given name, or `NULL`, from a `DM`

    7383:   Not Collective

    7385:   Input Parameters:
    7386: + dm   - The `DM` object
    7387: - name - The label name

    7389:   Output Parameter:
    7390: . label - The `DMLabel`, or `NULL` if the label is absent

    7392:   Default labels in a `DMPLEX`:
    7393: + "depth"       - Holds the depth (co-dimension) of each mesh point
    7394: . "celltype"    - Holds the topological type of each cell
    7395: . "ghost"       - If the DM is distributed with overlap, this marks the cells and faces in the overlap
    7396: . "Cell Sets"   - Mirrors the cell sets defined by GMsh and ExodusII
    7397: . "Face Sets"   - Mirrors the face sets defined by GMsh and ExodusII
    7398: - "Vertex Sets" - Mirrors the vertex sets defined by GMsh

    7400:   Level: intermediate

    7402: .seealso: [](ch_dmbase), `DM`, `DMLabel`, `DMHasLabel()`, `DMGetLabelByNum()`, `DMAddLabel()`, `DMCreateLabel()`, `DMPlexGetDepthLabel()`, `DMPlexGetCellType()`
    7403: @*/
    7404: PetscErrorCode DMGetLabel(DM dm, const char name[], DMLabel *label)
    7405: {
    7406:   DMLabelLink next = dm->labels;
    7407:   PetscBool   hasLabel;
    7408:   const char *lname;

    7410:   PetscFunctionBegin;
    7412:   PetscAssertPointer(name, 2);
    7413:   PetscAssertPointer(label, 3);
    7414:   *label = NULL;
    7415:   while (next) {
    7416:     PetscCall(PetscObjectGetName((PetscObject)next->label, &lname));
    7417:     PetscCall(PetscStrcmp(name, lname, &hasLabel));
    7418:     if (hasLabel) {
    7419:       *label = next->label;
    7420:       break;
    7421:     }
    7422:     next = next->next;
    7423:   }
    7424:   PetscFunctionReturn(PETSC_SUCCESS);
    7425: }

    7427: /*@
    7428:   DMGetLabelByNum - Return the nth label on a `DM`

    7430:   Not Collective

    7432:   Input Parameters:
    7433: + dm - The `DM` object
    7434: - n  - the label number

    7436:   Output Parameter:
    7437: . label - the label

    7439:   Level: intermediate

    7441: .seealso: [](ch_dmbase), `DM`, `DMLabel`, `DMAddLabel()`, `DMGetLabelValue()`, `DMSetLabelValue()`, `DMGetStratumIS()`
    7442: @*/
    7443: PetscErrorCode DMGetLabelByNum(DM dm, PetscInt n, DMLabel *label)
    7444: {
    7445:   DMLabelLink next = dm->labels;
    7446:   PetscInt    l    = 0;

    7448:   PetscFunctionBegin;
    7450:   PetscAssertPointer(label, 3);
    7451:   while (next) {
    7452:     if (l == n) {
    7453:       *label = next->label;
    7454:       PetscFunctionReturn(PETSC_SUCCESS);
    7455:     }
    7456:     ++l;
    7457:     next = next->next;
    7458:   }
    7459:   SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Label %" PetscInt_FMT " does not exist in this DM", n);
    7460: }

    7462: /*@
    7463:   DMAddLabel - Add the label to this `DM`

    7465:   Not Collective

    7467:   Input Parameters:
    7468: + dm    - The `DM` object
    7469: - label - The `DMLabel`

    7471:   Level: developer

    7473: .seealso: [](ch_dmbase), `DM`, `DMLabel`, `DMCreateLabel()`, `DMHasLabel()`, `DMGetLabelValue()`, `DMSetLabelValue()`, `DMGetStratumIS()`
    7474: @*/
    7475: PetscErrorCode DMAddLabel(DM dm, DMLabel label)
    7476: {
    7477:   DMLabelLink l, *p, tmpLabel;
    7478:   PetscBool   hasLabel;
    7479:   const char *lname;
    7480:   PetscBool   flg;

    7482:   PetscFunctionBegin;
    7484:   PetscCall(PetscObjectGetName((PetscObject)label, &lname));
    7485:   PetscCall(DMHasLabel(dm, lname, &hasLabel));
    7486:   PetscCheck(!hasLabel, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Label %s already exists in this DM", lname);
    7487:   PetscCall(PetscCalloc1(1, &tmpLabel));
    7488:   tmpLabel->label  = label;
    7489:   tmpLabel->output = PETSC_TRUE;
    7490:   for (p = &dm->labels; (l = *p); p = &l->next) { }
    7491:   *p = tmpLabel;
    7492:   PetscCall(PetscObjectReference((PetscObject)label));
    7493:   PetscCall(PetscStrcmp(lname, "depth", &flg));
    7494:   if (flg) dm->depthLabel = label;
    7495:   PetscCall(PetscStrcmp(lname, "celltype", &flg));
    7496:   if (flg) dm->celltypeLabel = label;
    7497:   PetscFunctionReturn(PETSC_SUCCESS);
    7498: }

    7500: // PetscClangLinter pragma ignore: -fdoc-section-header-unknown
    7501: /*@
    7502:   DMSetLabel - Replaces the label of a given name, or ignores it if the name is not present

    7504:   Not Collective

    7506:   Input Parameters:
    7507: + dm    - The `DM` object
    7508: - label - The `DMLabel`, having the same name, to substitute

    7510:   Default labels in a `DMPLEX`:
    7511: + "depth"       - Holds the depth (co-dimension) of each mesh point
    7512: . "celltype"    - Holds the topological type of each cell
    7513: . "ghost"       - If the DM is distributed with overlap, this marks the cells and faces in the overlap
    7514: . "Cell Sets"   - Mirrors the cell sets defined by GMsh and ExodusII
    7515: . "Face Sets"   - Mirrors the face sets defined by GMsh and ExodusII
    7516: - "Vertex Sets" - Mirrors the vertex sets defined by GMsh

    7518:   Level: intermediate

    7520: .seealso: [](ch_dmbase), `DM`, `DMLabel`, `DMCreateLabel()`, `DMHasLabel()`, `DMPlexGetDepthLabel()`, `DMPlexGetCellType()`
    7521: @*/
    7522: PetscErrorCode DMSetLabel(DM dm, DMLabel label)
    7523: {
    7524:   DMLabelLink next = dm->labels;
    7525:   PetscBool   hasLabel, flg;
    7526:   const char *name, *lname;

    7528:   PetscFunctionBegin;
    7531:   PetscCall(PetscObjectGetName((PetscObject)label, &name));
    7532:   while (next) {
    7533:     PetscCall(PetscObjectGetName((PetscObject)next->label, &lname));
    7534:     PetscCall(PetscStrcmp(name, lname, &hasLabel));
    7535:     if (hasLabel) {
    7536:       PetscCall(PetscObjectReference((PetscObject)label));
    7537:       PetscCall(PetscStrcmp(lname, "depth", &flg));
    7538:       if (flg) dm->depthLabel = label;
    7539:       PetscCall(PetscStrcmp(lname, "celltype", &flg));
    7540:       if (flg) dm->celltypeLabel = label;
    7541:       PetscCall(DMLabelDestroy(&next->label));
    7542:       next->label = label;
    7543:       break;
    7544:     }
    7545:     next = next->next;
    7546:   }
    7547:   PetscFunctionReturn(PETSC_SUCCESS);
    7548: }

    7550: /*@
    7551:   DMRemoveLabel - Remove the label given by name from this `DM`

    7553:   Not Collective

    7555:   Input Parameters:
    7556: + dm   - The `DM` object
    7557: - name - The label name

    7559:   Output Parameter:
    7560: . label - The `DMLabel`, or `NULL` if the label is absent. Pass in `NULL` to call `DMLabelDestroy()` on the label, otherwise the
    7561:           caller is responsible for calling `DMLabelDestroy()`.

    7563:   Level: developer

    7565: .seealso: [](ch_dmbase), `DM`, `DMLabel`, `DMCreateLabel()`, `DMHasLabel()`, `DMGetLabel()`, `DMGetLabelValue()`, `DMSetLabelValue()`, `DMLabelDestroy()`, `DMRemoveLabelBySelf()`
    7566: @*/
    7567: PetscErrorCode DMRemoveLabel(DM dm, const char name[], DMLabel *label)
    7568: {
    7569:   DMLabelLink link, *pnext;
    7570:   PetscBool   hasLabel;
    7571:   const char *lname;

    7573:   PetscFunctionBegin;
    7575:   PetscAssertPointer(name, 2);
    7576:   if (label) {
    7577:     PetscAssertPointer(label, 3);
    7578:     *label = NULL;
    7579:   }
    7580:   for (pnext = &dm->labels; (link = *pnext); pnext = &link->next) {
    7581:     PetscCall(PetscObjectGetName((PetscObject)link->label, &lname));
    7582:     PetscCall(PetscStrcmp(name, lname, &hasLabel));
    7583:     if (hasLabel) {
    7584:       *pnext = link->next; /* Remove from list */
    7585:       PetscCall(PetscStrcmp(name, "depth", &hasLabel));
    7586:       if (hasLabel) dm->depthLabel = NULL;
    7587:       PetscCall(PetscStrcmp(name, "celltype", &hasLabel));
    7588:       if (hasLabel) dm->celltypeLabel = NULL;
    7589:       if (label) *label = link->label;
    7590:       else PetscCall(DMLabelDestroy(&link->label));
    7591:       PetscCall(PetscFree(link));
    7592:       break;
    7593:     }
    7594:   }
    7595:   PetscFunctionReturn(PETSC_SUCCESS);
    7596: }

    7598: /*@
    7599:   DMRemoveLabelBySelf - Remove the label from this `DM`

    7601:   Not Collective

    7603:   Input Parameters:
    7604: + dm           - The `DM` object
    7605: . label        - The `DMLabel` to be removed from the `DM`
    7606: - failNotFound - Should it fail if the label is not found in the `DM`?

    7608:   Level: developer

    7610:   Note:
    7611:   Only exactly the same instance is removed if found, name match is ignored.
    7612:   If the `DM` has an exclusive reference to the label, the label gets destroyed and
    7613:   *label nullified.

    7615: .seealso: [](ch_dmbase), `DM`, `DMLabel`, `DMCreateLabel()`, `DMHasLabel()`, `DMGetLabel()`, `DMGetLabelValue()`, `DMSetLabelValue()`, `DMLabelDestroy()`, `DMRemoveLabel()`
    7616: @*/
    7617: PetscErrorCode DMRemoveLabelBySelf(DM dm, DMLabel *label, PetscBool failNotFound)
    7618: {
    7619:   DMLabelLink link, *pnext;
    7620:   PetscBool   hasLabel = PETSC_FALSE;

    7622:   PetscFunctionBegin;
    7624:   PetscAssertPointer(label, 2);
    7625:   if (!*label && !failNotFound) PetscFunctionReturn(PETSC_SUCCESS);
    7628:   for (pnext = &dm->labels; (link = *pnext); pnext = &link->next) {
    7629:     if (*label == link->label) {
    7630:       hasLabel = PETSC_TRUE;
    7631:       *pnext   = link->next; /* Remove from list */
    7632:       if (*label == dm->depthLabel) dm->depthLabel = NULL;
    7633:       if (*label == dm->celltypeLabel) dm->celltypeLabel = NULL;
    7634:       if (((PetscObject)link->label)->refct < 2) *label = NULL; /* nullify if exclusive reference */
    7635:       PetscCall(DMLabelDestroy(&link->label));
    7636:       PetscCall(PetscFree(link));
    7637:       break;
    7638:     }
    7639:   }
    7640:   PetscCheck(hasLabel || !failNotFound, PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_WRONG, "Given label not found in DM");
    7641:   PetscFunctionReturn(PETSC_SUCCESS);
    7642: }

    7644: /*@
    7645:   DMGetLabelOutput - Get the output flag for a given label

    7647:   Not Collective

    7649:   Input Parameters:
    7650: + dm   - The `DM` object
    7651: - name - The label name

    7653:   Output Parameter:
    7654: . output - The flag for output

    7656:   Level: developer

    7658: .seealso: [](ch_dmbase), `DM`, `DMLabel`, `DMSetLabelOutput()`, `DMCreateLabel()`, `DMHasLabel()`, `DMGetLabelValue()`, `DMSetLabelValue()`, `DMGetStratumIS()`
    7659: @*/
    7660: PetscErrorCode DMGetLabelOutput(DM dm, const char name[], PetscBool *output)
    7661: {
    7662:   DMLabelLink next = dm->labels;
    7663:   const char *lname;

    7665:   PetscFunctionBegin;
    7667:   PetscAssertPointer(name, 2);
    7668:   PetscAssertPointer(output, 3);
    7669:   while (next) {
    7670:     PetscBool flg;

    7672:     PetscCall(PetscObjectGetName((PetscObject)next->label, &lname));
    7673:     PetscCall(PetscStrcmp(name, lname, &flg));
    7674:     if (flg) {
    7675:       *output = next->output;
    7676:       PetscFunctionReturn(PETSC_SUCCESS);
    7677:     }
    7678:     next = next->next;
    7679:   }
    7680:   SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "No label named %s was present in this dm", name);
    7681: }

    7683: /*@
    7684:   DMSetLabelOutput - Set if a given label should be saved to a `PetscViewer` in calls to `DMView()`

    7686:   Not Collective

    7688:   Input Parameters:
    7689: + dm     - The `DM` object
    7690: . name   - The label name
    7691: - output - `PETSC_TRUE` to save the label to the viewer

    7693:   Level: developer

    7695: .seealso: [](ch_dmbase), `DM`, `DMLabel`, `DMGetOutputFlag()`, `DMGetLabelOutput()`, `DMCreateLabel()`, `DMHasLabel()`, `DMGetLabelValue()`, `DMSetLabelValue()`, `DMGetStratumIS()`
    7696: @*/
    7697: PetscErrorCode DMSetLabelOutput(DM dm, const char name[], PetscBool output)
    7698: {
    7699:   DMLabelLink next = dm->labels;
    7700:   const char *lname;

    7702:   PetscFunctionBegin;
    7704:   PetscAssertPointer(name, 2);
    7705:   while (next) {
    7706:     PetscBool flg;

    7708:     PetscCall(PetscObjectGetName((PetscObject)next->label, &lname));
    7709:     PetscCall(PetscStrcmp(name, lname, &flg));
    7710:     if (flg) {
    7711:       next->output = output;
    7712:       PetscFunctionReturn(PETSC_SUCCESS);
    7713:     }
    7714:     next = next->next;
    7715:   }
    7716:   SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "No label named %s was present in this dm", name);
    7717: }

    7719: /*@
    7720:   DMCopyLabels - Copy labels from one `DM` mesh to another `DM` with a superset of the points

    7722:   Collective

    7724:   Input Parameters:
    7725: + dmA   - The `DM` object with initial labels
    7726: . dmB   - The `DM` object to which labels are copied
    7727: . mode  - Copy labels by pointers (`PETSC_OWN_POINTER`) or duplicate them (`PETSC_COPY_VALUES`)
    7728: . all   - Copy all labels including "depth", "dim", and "celltype" (`PETSC_TRUE`) which are otherwise ignored (`PETSC_FALSE`)
    7729: - emode - How to behave when a `DMLabel` in the source and destination `DM`s with the same name is encountered (see `DMCopyLabelsMode`)

    7731:   Level: intermediate

    7733:   Note:
    7734:   This is typically used when interpolating or otherwise adding to a mesh, or testing.

    7736: .seealso: [](ch_dmbase), `DM`, `DMLabel`, `DMAddLabel()`, `DMCopyLabelsMode`
    7737: @*/
    7738: PetscErrorCode DMCopyLabels(DM dmA, DM dmB, PetscCopyMode mode, PetscBool all, DMCopyLabelsMode emode)
    7739: {
    7740:   DMLabel     label, labelNew, labelOld;
    7741:   const char *name;
    7742:   PetscBool   flg;
    7743:   DMLabelLink link;

    7745:   PetscFunctionBegin;
    7750:   PetscCheck(mode != PETSC_USE_POINTER, PetscObjectComm((PetscObject)dmA), PETSC_ERR_SUP, "PETSC_USE_POINTER not supported for objects");
    7751:   if (dmA == dmB) PetscFunctionReturn(PETSC_SUCCESS);
    7752:   for (link = dmA->labels; link; link = link->next) {
    7753:     label = link->label;
    7754:     PetscCall(PetscObjectGetName((PetscObject)label, &name));
    7755:     if (!all) {
    7756:       PetscCall(PetscStrcmp(name, "depth", &flg));
    7757:       if (flg) continue;
    7758:       PetscCall(PetscStrcmp(name, "dim", &flg));
    7759:       if (flg) continue;
    7760:       PetscCall(PetscStrcmp(name, "celltype", &flg));
    7761:       if (flg) continue;
    7762:     }
    7763:     PetscCall(DMGetLabel(dmB, name, &labelOld));
    7764:     if (labelOld) {
    7765:       switch (emode) {
    7766:       case DM_COPY_LABELS_KEEP:
    7767:         continue;
    7768:       case DM_COPY_LABELS_REPLACE:
    7769:         PetscCall(DMRemoveLabelBySelf(dmB, &labelOld, PETSC_TRUE));
    7770:         break;
    7771:       case DM_COPY_LABELS_FAIL:
    7772:         SETERRQ(PetscObjectComm((PetscObject)dmA), PETSC_ERR_ARG_OUTOFRANGE, "Label %s already exists in destination DM", name);
    7773:       default:
    7774:         SETERRQ(PetscObjectComm((PetscObject)dmA), PETSC_ERR_ARG_OUTOFRANGE, "Unhandled DMCopyLabelsMode %d", (int)emode);
    7775:       }
    7776:     }
    7777:     if (mode == PETSC_COPY_VALUES) PetscCall(DMLabelDuplicate(label, &labelNew));
    7778:     else labelNew = label;
    7779:     PetscCall(DMAddLabel(dmB, labelNew));
    7780:     if (mode == PETSC_COPY_VALUES) PetscCall(DMLabelDestroy(&labelNew));
    7781:   }
    7782:   PetscFunctionReturn(PETSC_SUCCESS);
    7783: }

    7785: /*@C
    7786:   DMCompareLabels - Compare labels between two `DM` objects

    7788:   Collective; No Fortran Support

    7790:   Input Parameters:
    7791: + dm0 - First `DM` object
    7792: - dm1 - Second `DM` object

    7794:   Output Parameters:
    7795: + equal   - (Optional) Flag whether labels of `dm0` and `dm1` are the same
    7796: - message - (Optional) Message describing the difference, or `NULL` if there is no difference

    7798:   Level: intermediate

    7800:   Notes:
    7801:   The output flag equal will be the same on all processes.

    7803:   If equal is passed as `NULL` and difference is found, an error is thrown on all processes.

    7805:   Make sure to pass equal is `NULL` on all processes or none of them.

    7807:   The output message is set independently on each rank.

    7809:   message must be freed with `PetscFree()`

    7811:   If message is passed as `NULL` and a difference is found, the difference description is printed to `stderr` in synchronized manner.

    7813:   Make sure to pass message as `NULL` on all processes or no processes.

    7815:   Labels are matched by name. If the number of labels and their names are equal,
    7816:   `DMLabelCompare()` is used to compare each pair of labels with the same name.

    7818:   Developer Note:
    7819:   Cannot automatically generate the Fortran stub because `message` must be freed with `PetscFree()`

    7821: .seealso: [](ch_dmbase), `DM`, `DMLabel`, `DMAddLabel()`, `DMCopyLabelsMode`, `DMLabelCompare()`
    7822: @*/
    7823: PetscErrorCode DMCompareLabels(DM dm0, DM dm1, PetscBool *equal, char *message[]) PeNS
    7824: {
    7825:   PetscInt    n, i;
    7826:   char        msg[PETSC_MAX_PATH_LEN] = "";
    7827:   PetscBool   eq;
    7828:   MPI_Comm    comm;
    7829:   PetscMPIInt rank;

    7831:   PetscFunctionBegin;
    7834:   PetscCheckSameComm(dm0, 1, dm1, 2);
    7835:   if (equal) PetscAssertPointer(equal, 3);
    7836:   if (message) PetscAssertPointer(message, 4);
    7837:   PetscCall(PetscObjectGetComm((PetscObject)dm0, &comm));
    7838:   PetscCallMPI(MPI_Comm_rank(comm, &rank));
    7839:   {
    7840:     PetscInt n1;

    7842:     PetscCall(DMGetNumLabels(dm0, &n));
    7843:     PetscCall(DMGetNumLabels(dm1, &n1));
    7844:     eq = (PetscBool)(n == n1);
    7845:     if (!eq) PetscCall(PetscSNPrintf(msg, sizeof(msg), "Number of labels in dm0 = %" PetscInt_FMT " != %" PetscInt_FMT " = Number of labels in dm1", n, n1));
    7846:     PetscCallMPI(MPIU_Allreduce(MPI_IN_PLACE, &eq, 1, MPI_C_BOOL, MPI_LAND, comm));
    7847:     if (!eq) goto finish;
    7848:   }
    7849:   for (i = 0; i < n; i++) {
    7850:     DMLabel     l0, l1;
    7851:     const char *name;
    7852:     char       *msgInner;

    7854:     /* Ignore label order */
    7855:     PetscCall(DMGetLabelByNum(dm0, i, &l0));
    7856:     PetscCall(PetscObjectGetName((PetscObject)l0, &name));
    7857:     PetscCall(DMGetLabel(dm1, name, &l1));
    7858:     if (!l1) {
    7859:       PetscCall(PetscSNPrintf(msg, sizeof(msg), "Label \"%s\" (#%" PetscInt_FMT " in dm0) not found in dm1", name, i));
    7860:       eq = PETSC_FALSE;
    7861:       break;
    7862:     }
    7863:     PetscCall(DMLabelCompare(comm, l0, l1, &eq, &msgInner));
    7864:     PetscCall(PetscStrncpy(msg, msgInner, sizeof(msg)));
    7865:     PetscCall(PetscFree(msgInner));
    7866:     if (!eq) break;
    7867:   }
    7868:   PetscCallMPI(MPIU_Allreduce(MPI_IN_PLACE, &eq, 1, MPI_C_BOOL, MPI_LAND, comm));
    7869: finish:
    7870:   /* If message output arg not set, print to stderr */
    7871:   if (message) {
    7872:     *message = NULL;
    7873:     if (msg[0]) PetscCall(PetscStrallocpy(msg, message));
    7874:   } else {
    7875:     if (msg[0]) PetscCall(PetscSynchronizedFPrintf(comm, PETSC_STDERR, "[%d] %s\n", rank, msg));
    7876:     PetscCall(PetscSynchronizedFlush(comm, PETSC_STDERR));
    7877:   }
    7878:   /* If same output arg not ser and labels are not equal, throw error */
    7879:   if (equal) *equal = eq;
    7880:   else PetscCheck(eq, comm, PETSC_ERR_ARG_INCOMP, "DMLabels are not the same in dm0 and dm1");
    7881:   PetscFunctionReturn(PETSC_SUCCESS);
    7882: }

    7884: PetscErrorCode DMSetLabelValue_Fast(DM dm, DMLabel *label, const char name[], PetscInt point, PetscInt value)
    7885: {
    7886:   PetscFunctionBegin;
    7887:   PetscAssertPointer(label, 2);
    7888:   if (!*label) {
    7889:     PetscCall(DMCreateLabel(dm, name));
    7890:     PetscCall(DMGetLabel(dm, name, label));
    7891:   }
    7892:   PetscCall(DMLabelSetValue(*label, point, value));
    7893:   PetscFunctionReturn(PETSC_SUCCESS);
    7894: }

    7896: /*
    7897:   Many mesh programs, such as Triangle and TetGen, allow only a single label for each mesh point. Therefore, we would
    7898:   like to encode all label IDs using a single, universal label. We can do this by assigning an integer to every
    7899:   (label, id) pair in the DM.

    7901:   However, a mesh point can have multiple labels, so we must separate all these values. We will assign a bit range to
    7902:   each label.
    7903: */
    7904: PetscErrorCode DMUniversalLabelCreate(DM dm, DMUniversalLabel *universal)
    7905: {
    7906:   DMUniversalLabel ul;
    7907:   PetscBool       *active;
    7908:   PetscInt         pStart, pEnd, p, Nl, l, m;

    7910:   PetscFunctionBegin;
    7911:   PetscCall(PetscMalloc1(1, &ul));
    7912:   PetscCall(DMLabelCreate(PETSC_COMM_SELF, "universal", &ul->label));
    7913:   PetscCall(DMGetNumLabels(dm, &Nl));
    7914:   PetscCall(PetscCalloc1(Nl, &active));
    7915:   ul->Nl = 0;
    7916:   for (l = 0; l < Nl; ++l) {
    7917:     PetscBool   isdepth, iscelltype;
    7918:     const char *name;

    7920:     PetscCall(DMGetLabelName(dm, l, &name));
    7921:     PetscCall(PetscStrncmp(name, "depth", 6, &isdepth));
    7922:     PetscCall(PetscStrncmp(name, "celltype", 9, &iscelltype));
    7923:     active[l] = !(isdepth || iscelltype) ? PETSC_TRUE : PETSC_FALSE;
    7924:     if (active[l]) ++ul->Nl;
    7925:   }
    7926:   PetscCall(PetscCalloc5(ul->Nl, &ul->names, ul->Nl, &ul->indices, ul->Nl + 1, &ul->offsets, ul->Nl + 1, &ul->bits, ul->Nl, &ul->masks));
    7927:   ul->Nv = 0;
    7928:   for (l = 0, m = 0; l < Nl; ++l) {
    7929:     DMLabel     label;
    7930:     PetscInt    nv;
    7931:     const char *name;

    7933:     if (!active[l]) continue;
    7934:     PetscCall(DMGetLabelName(dm, l, &name));
    7935:     PetscCall(DMGetLabelByNum(dm, l, &label));
    7936:     PetscCall(DMLabelGetNumValues(label, &nv));
    7937:     PetscCall(PetscStrallocpy(name, &ul->names[m]));
    7938:     ul->indices[m] = l;
    7939:     ul->Nv += nv;
    7940:     ul->offsets[m + 1] = nv;
    7941:     ul->bits[m + 1]    = PetscCeilReal(PetscLog2Real(nv + 1));
    7942:     ++m;
    7943:   }
    7944:   for (l = 1; l <= ul->Nl; ++l) {
    7945:     ul->offsets[l] = ul->offsets[l - 1] + ul->offsets[l];
    7946:     ul->bits[l]    = ul->bits[l - 1] + ul->bits[l];
    7947:   }
    7948:   for (l = 0; l < ul->Nl; ++l) {
    7949:     PetscInt b;

    7951:     ul->masks[l] = 0;
    7952:     for (b = ul->bits[l]; b < ul->bits[l + 1]; ++b) ul->masks[l] |= 1 << b;
    7953:   }
    7954:   PetscCall(PetscMalloc1(ul->Nv, &ul->values));
    7955:   for (l = 0, m = 0; l < Nl; ++l) {
    7956:     DMLabel         label;
    7957:     IS              valueIS;
    7958:     const PetscInt *varr;
    7959:     PetscInt        nv, v;

    7961:     if (!active[l]) continue;
    7962:     PetscCall(DMGetLabelByNum(dm, l, &label));
    7963:     PetscCall(DMLabelGetNumValues(label, &nv));
    7964:     PetscCall(DMLabelGetValueIS(label, &valueIS));
    7965:     PetscCall(ISGetIndices(valueIS, &varr));
    7966:     for (v = 0; v < nv; ++v) ul->values[ul->offsets[m] + v] = varr[v];
    7967:     PetscCall(ISRestoreIndices(valueIS, &varr));
    7968:     PetscCall(ISDestroy(&valueIS));
    7969:     PetscCall(PetscSortInt(nv, &ul->values[ul->offsets[m]]));
    7970:     ++m;
    7971:   }
    7972:   PetscCall(DMPlexGetChart(dm, &pStart, &pEnd));
    7973:   for (p = pStart; p < pEnd; ++p) {
    7974:     PetscInt  uval   = 0;
    7975:     PetscBool marked = PETSC_FALSE;

    7977:     for (l = 0, m = 0; l < Nl; ++l) {
    7978:       DMLabel  label;
    7979:       PetscInt val, defval, loc, nv;

    7981:       if (!active[l]) continue;
    7982:       PetscCall(DMGetLabelByNum(dm, l, &label));
    7983:       PetscCall(DMLabelGetValue(label, p, &val));
    7984:       PetscCall(DMLabelGetDefaultValue(label, &defval));
    7985:       if (val == defval) {
    7986:         ++m;
    7987:         continue;
    7988:       }
    7989:       nv     = ul->offsets[m + 1] - ul->offsets[m];
    7990:       marked = PETSC_TRUE;
    7991:       PetscCall(PetscFindInt(val, nv, &ul->values[ul->offsets[m]], &loc));
    7992:       PetscCheck(loc >= 0, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Label value %" PetscInt_FMT " not found in compression array", val);
    7993:       uval += (loc + 1) << ul->bits[m];
    7994:       ++m;
    7995:     }
    7996:     if (marked) PetscCall(DMLabelSetValue(ul->label, p, uval));
    7997:   }
    7998:   PetscCall(PetscFree(active));
    7999:   *universal = ul;
    8000:   PetscFunctionReturn(PETSC_SUCCESS);
    8001: }

    8003: PetscErrorCode DMUniversalLabelDestroy(DMUniversalLabel *universal)
    8004: {
    8005:   PetscInt l;

    8007:   PetscFunctionBegin;
    8008:   for (l = 0; l < (*universal)->Nl; ++l) PetscCall(PetscFree((*universal)->names[l]));
    8009:   PetscCall(DMLabelDestroy(&(*universal)->label));
    8010:   PetscCall(PetscFree5((*universal)->names, (*universal)->indices, (*universal)->offsets, (*universal)->bits, (*universal)->masks));
    8011:   PetscCall(PetscFree((*universal)->values));
    8012:   PetscCall(PetscFree(*universal));
    8013:   *universal = NULL;
    8014:   PetscFunctionReturn(PETSC_SUCCESS);
    8015: }

    8017: PetscErrorCode DMUniversalLabelGetLabel(DMUniversalLabel ul, DMLabel *ulabel)
    8018: {
    8019:   PetscFunctionBegin;
    8020:   PetscAssertPointer(ulabel, 2);
    8021:   *ulabel = ul->label;
    8022:   PetscFunctionReturn(PETSC_SUCCESS);
    8023: }

    8025: PetscErrorCode DMUniversalLabelCreateLabels(DMUniversalLabel ul, PetscBool preserveOrder, DM dm)
    8026: {
    8027:   PetscInt Nl = ul->Nl, l;

    8029:   PetscFunctionBegin;
    8031:   for (l = 0; l < Nl; ++l) {
    8032:     if (preserveOrder) PetscCall(DMCreateLabelAtIndex(dm, ul->indices[l], ul->names[l]));
    8033:     else PetscCall(DMCreateLabel(dm, ul->names[l]));
    8034:   }
    8035:   if (preserveOrder) {
    8036:     for (l = 0; l < ul->Nl; ++l) {
    8037:       const char *name;
    8038:       PetscBool   match;

    8040:       PetscCall(DMGetLabelName(dm, ul->indices[l], &name));
    8041:       PetscCall(PetscStrcmp(name, ul->names[l], &match));
    8042:       PetscCheck(match, PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_WRONG, "Label %" PetscInt_FMT " name %s does not match new name %s", l, name, ul->names[l]);
    8043:     }
    8044:   }
    8045:   PetscFunctionReturn(PETSC_SUCCESS);
    8046: }

    8048: PetscErrorCode DMUniversalLabelSetLabelValue(DMUniversalLabel ul, DM dm, PetscBool useIndex, PetscInt p, PetscInt value)
    8049: {
    8050:   PetscInt l;

    8052:   PetscFunctionBegin;
    8053:   for (l = 0; l < ul->Nl; ++l) {
    8054:     DMLabel  label;
    8055:     PetscInt lval = (value & ul->masks[l]) >> ul->bits[l];

    8057:     if (lval) {
    8058:       if (useIndex) PetscCall(DMGetLabelByNum(dm, ul->indices[l], &label));
    8059:       else PetscCall(DMGetLabel(dm, ul->names[l], &label));
    8060:       PetscCall(DMLabelSetValue(label, p, ul->values[ul->offsets[l] + lval - 1]));
    8061:     }
    8062:   }
    8063:   PetscFunctionReturn(PETSC_SUCCESS);
    8064: }

    8066: /*@
    8067:   DMGetCoarseDM - Get the coarse `DM`from which this `DM` was obtained by refinement

    8069:   Not Collective

    8071:   Input Parameter:
    8072: . dm - The `DM` object

    8074:   Output Parameter:
    8075: . cdm - The coarse `DM`

    8077:   Level: intermediate

    8079: .seealso: [](ch_dmbase), `DM`, `DMSetCoarseDM()`, `DMCoarsen()`
    8080: @*/
    8081: PetscErrorCode DMGetCoarseDM(DM dm, DM *cdm)
    8082: {
    8083:   PetscFunctionBegin;
    8085:   PetscAssertPointer(cdm, 2);
    8086:   *cdm = dm->coarseMesh;
    8087:   PetscFunctionReturn(PETSC_SUCCESS);
    8088: }

    8090: /*@
    8091:   DMSetCoarseDM - Set the coarse `DM` from which this `DM` was obtained by refinement

    8093:   Input Parameters:
    8094: + dm  - The `DM` object
    8095: - cdm - The coarse `DM`

    8097:   Level: intermediate

    8099:   Note:
    8100:   Normally this is set automatically by `DMRefine()`

    8102: .seealso: [](ch_dmbase), `DM`, `DMGetCoarseDM()`, `DMCoarsen()`, `DMSetRefine()`, `DMSetFineDM()`
    8103: @*/
    8104: PetscErrorCode DMSetCoarseDM(DM dm, DM cdm)
    8105: {
    8106:   PetscFunctionBegin;
    8109:   if (dm == cdm) cdm = NULL;
    8110:   PetscCall(PetscObjectReference((PetscObject)cdm));
    8111:   PetscCall(DMDestroy(&dm->coarseMesh));
    8112:   dm->coarseMesh = cdm;
    8113:   PetscFunctionReturn(PETSC_SUCCESS);
    8114: }

    8116: /*@
    8117:   DMGetFineDM - Get the fine mesh from which this `DM` was obtained by coarsening

    8119:   Input Parameter:
    8120: . dm - The `DM` object

    8122:   Output Parameter:
    8123: . fdm - The fine `DM`

    8125:   Level: intermediate

    8127: .seealso: [](ch_dmbase), `DM`, `DMSetFineDM()`, `DMCoarsen()`, `DMRefine()`
    8128: @*/
    8129: PetscErrorCode DMGetFineDM(DM dm, DM *fdm)
    8130: {
    8131:   PetscFunctionBegin;
    8133:   PetscAssertPointer(fdm, 2);
    8134:   *fdm = dm->fineMesh;
    8135:   PetscFunctionReturn(PETSC_SUCCESS);
    8136: }

    8138: /*@
    8139:   DMSetFineDM - Set the fine mesh from which this was obtained by coarsening

    8141:   Input Parameters:
    8142: + dm  - The `DM` object
    8143: - fdm - The fine `DM`

    8145:   Level: developer

    8147:   Note:
    8148:   Normally this is set automatically by `DMCoarsen()`

    8150: .seealso: [](ch_dmbase), `DM`, `DMGetFineDM()`, `DMCoarsen()`, `DMRefine()`
    8151: @*/
    8152: PetscErrorCode DMSetFineDM(DM dm, DM fdm)
    8153: {
    8154:   PetscFunctionBegin;
    8157:   if (dm == fdm) fdm = NULL;
    8158:   PetscCall(PetscObjectReference((PetscObject)fdm));
    8159:   PetscCall(DMDestroy(&dm->fineMesh));
    8160:   dm->fineMesh = fdm;
    8161:   PetscFunctionReturn(PETSC_SUCCESS);
    8162: }

    8164: /*@C
    8165:   DMAddBoundary - Add a boundary condition, for a single field, to a model represented by a `DM`

    8167:   Collective

    8169:   Input Parameters:
    8170: + dm       - The `DM`, with a `PetscDS` that matches the problem being constrained
    8171: . type     - The type of condition, e.g. `DM_BC_ESSENTIAL_ANALYTIC`, `DM_BC_ESSENTIAL_FIELD` (Dirichlet), or `DM_BC_NATURAL` (Neumann)
    8172: . name     - The BC name
    8173: . label    - The label defining constrained points
    8174: . Nv       - The number of `DMLabel` values for constrained points
    8175: . values   - An array of values for constrained points
    8176: . field    - The field to constrain
    8177: . Nc       - The number of constrained field components (0 will constrain all components)
    8178: . comps    - An array of constrained component numbers
    8179: . bcFunc   - A pointwise function giving boundary values
    8180: . bcFunc_t - A pointwise function giving the time derivative of the boundary values, or `NULL`
    8181: - ctx      - An optional application context for `bcFunc`

    8183:   Output Parameter:
    8184: . bd - (Optional) Boundary number

    8186:   Options Database Keys:
    8187: + -bc_NAME values     - Overrides the boundary ids for boundary named NAME
    8188: - -bc_NAME_comp comps - Overrides the boundary components for boundary named NAME

    8190:   Level: intermediate

    8192:   Notes:
    8193:   If the `DM` is of type `DMPLEX` and the field is of type `PetscFE`, then this function completes the label using `DMPlexLabelComplete()`.

    8195:   Both bcFunc and bcFunc_t will depend on the boundary condition type. If the type if `DM_BC_ESSENTIAL`, then the calling sequence is\:
    8196: .vb
    8197:  void bcFunc(PetscInt dim, PetscReal time, const PetscReal x[], PetscInt Nc, PetscScalar bcval[])
    8198: .ve

    8200:   If the type is `DM_BC_ESSENTIAL_FIELD` or other _FIELD value, then the calling sequence is\:

    8202: .vb
    8203:   void bcFunc(PetscInt dim, PetscInt Nf, PetscInt NfAux,
    8204:               const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[],
    8205:               const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[],
    8206:               PetscReal time, const PetscReal x[], PetscScalar bcval[])
    8207: .ve
    8208: + dim - the spatial dimension
    8209: . Nf - the number of fields
    8210: . uOff - the offset into u[] and u_t[] for each field
    8211: . uOff_x - the offset into u_x[] for each field
    8212: . u - each field evaluated at the current point
    8213: . u_t - the time derivative of each field evaluated at the current point
    8214: . u_x - the gradient of each field evaluated at the current point
    8215: . aOff - the offset into a[] and a_t[] for each auxiliary field
    8216: . aOff_x - the offset into a_x[] for each auxiliary field
    8217: . a - each auxiliary field evaluated at the current point
    8218: . a_t - the time derivative of each auxiliary field evaluated at the current point
    8219: . a_x - the gradient of auxiliary each field evaluated at the current point
    8220: . t - current time
    8221: . x - coordinates of the current point
    8222: . numConstants - number of constant parameters
    8223: . constants - constant parameters
    8224: - bcval - output values at the current point

    8226: .seealso: [](ch_dmbase), `DM`, `DSGetBoundary()`, `PetscDSAddBoundary()`
    8227: @*/
    8228: PetscErrorCode DMAddBoundary(DM dm, DMBoundaryConditionType type, const char name[], DMLabel label, PetscInt Nv, const PetscInt values[], PetscInt field, PetscInt Nc, const PetscInt comps[], PetscVoidFn *bcFunc, PetscVoidFn *bcFunc_t, PetscCtx ctx, PetscInt *bd)
    8229: {
    8230:   PetscDS ds;

    8232:   PetscFunctionBegin;
    8239:   PetscCheck(!dm->localSection, PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_WRONGSTATE, "Cannot add boundary to DM after creating local section");
    8240:   PetscCall(DMGetDS(dm, &ds));
    8241:   /* Complete label */
    8242:   if (label) {
    8243:     PetscObject  obj;
    8244:     PetscClassId id;

    8246:     PetscCall(DMGetField(dm, field, NULL, &obj));
    8247:     PetscCall(PetscObjectGetClassId(obj, &id));
    8248:     if (id == PETSCFE_CLASSID) {
    8249:       DM plex;

    8251:       PetscCall(DMConvert(dm, DMPLEX, &plex));
    8252:       if (plex) PetscCall(DMPlexLabelComplete(plex, label));
    8253:       PetscCall(DMDestroy(&plex));
    8254:     }
    8255:   }
    8256:   PetscCall(PetscDSAddBoundary(ds, type, name, label, Nv, values, field, Nc, comps, bcFunc, bcFunc_t, ctx, bd));
    8257:   PetscFunctionReturn(PETSC_SUCCESS);
    8258: }

    8260: /* TODO Remove this since now the structures are the same */
    8261: static PetscErrorCode DMPopulateBoundary(DM dm)
    8262: {
    8263:   PetscDS     ds;
    8264:   DMBoundary *lastnext;
    8265:   DSBoundary  dsbound;

    8267:   PetscFunctionBegin;
    8268:   PetscCall(DMGetDS(dm, &ds));
    8269:   dsbound = ds->boundary;
    8270:   if (dm->boundary) {
    8271:     DMBoundary next = dm->boundary;

    8273:     /* quick check to see if the PetscDS has changed */
    8274:     if (next->dsboundary == dsbound) PetscFunctionReturn(PETSC_SUCCESS);
    8275:     /* the PetscDS has changed: tear down and rebuild */
    8276:     while (next) {
    8277:       DMBoundary b = next;

    8279:       next = b->next;
    8280:       PetscCall(PetscFree(b));
    8281:     }
    8282:     dm->boundary = NULL;
    8283:   }

    8285:   lastnext = &dm->boundary;
    8286:   while (dsbound) {
    8287:     DMBoundary dmbound;

    8289:     PetscCall(PetscNew(&dmbound));
    8290:     dmbound->dsboundary = dsbound;
    8291:     dmbound->label      = dsbound->label;
    8292:     /* push on the back instead of the front so that it is in the same order as in the PetscDS */
    8293:     *lastnext = dmbound;
    8294:     lastnext  = &dmbound->next;
    8295:     dsbound   = dsbound->next;
    8296:   }
    8297:   PetscFunctionReturn(PETSC_SUCCESS);
    8298: }

    8300: /*@
    8301:   DMIsBoundaryPoint - Determine whether a mesh point lies on a `DM` boundary

    8303:   Not Collective

    8305:   Input Parameters:
    8306: + dm    - the `DM` object
    8307: - point - the mesh point number

    8309:   Output Parameter:
    8310: . isBd - `PETSC_TRUE` if `point` belongs to any boundary label registered on the `DM`

    8312:   Level: developer

    8314: .seealso: [](ch_dmbase), `DM`, `DMLabel`, `DMAddBoundary()`, `PetscDSGetBoundary()`
    8315: @*/
    8316: PetscErrorCode DMIsBoundaryPoint(DM dm, PetscInt point, PetscBool *isBd)
    8317: {
    8318:   DMBoundary b;

    8320:   PetscFunctionBegin;
    8322:   PetscAssertPointer(isBd, 3);
    8323:   *isBd = PETSC_FALSE;
    8324:   PetscCall(DMPopulateBoundary(dm));
    8325:   b = dm->boundary;
    8326:   while (b && !*isBd) {
    8327:     DMLabel    label = b->label;
    8328:     DSBoundary dsb   = b->dsboundary;
    8329:     PetscInt   i;

    8331:     if (label) {
    8332:       for (i = 0; i < dsb->Nv && !*isBd; ++i) PetscCall(DMLabelStratumHasPoint(label, dsb->values[i], point, isBd));
    8333:     }
    8334:     b = b->next;
    8335:   }
    8336:   PetscFunctionReturn(PETSC_SUCCESS);
    8337: }

    8339: /*@
    8340:   DMHasBound - Determine whether a bound condition was specified

    8342:   Logically collective

    8344:   Input Parameter:
    8345: . dm - The `DM`, with a `PetscDS` that matches the problem being constrained

    8347:   Output Parameter:
    8348: . hasBound - Flag indicating if a bound condition was specified

    8350:   Level: intermediate

    8352: .seealso: [](ch_dmbase), `DM`, `DSAddBoundary()`, `PetscDSAddBoundary()`
    8353: @*/
    8354: PetscErrorCode DMHasBound(DM dm, PetscBool *hasBound)
    8355: {
    8356:   PetscDS  ds;
    8357:   PetscInt Nf, numBd;

    8359:   PetscFunctionBegin;
    8360:   *hasBound = PETSC_FALSE;
    8361:   PetscCall(DMGetDS(dm, &ds));
    8362:   PetscCall(PetscDSGetNumFields(ds, &Nf));
    8363:   for (PetscInt f = 0; f < Nf; ++f) {
    8364:     PetscSimplePointFn *lfunc, *ufunc;

    8366:     PetscCall(PetscDSGetLowerBound(ds, f, &lfunc, NULL));
    8367:     PetscCall(PetscDSGetUpperBound(ds, f, &ufunc, NULL));
    8368:     if (lfunc || ufunc) *hasBound = PETSC_TRUE;
    8369:   }

    8371:   PetscCall(PetscDSGetNumBoundary(ds, &numBd));
    8372:   PetscCall(PetscDSUpdateBoundaryLabels(ds, dm));
    8373:   for (PetscInt b = 0; b < numBd; ++b) {
    8374:     PetscWeakForm           wf;
    8375:     DMBoundaryConditionType type;
    8376:     const char             *name;
    8377:     DMLabel                 label;
    8378:     PetscInt                numids;
    8379:     const PetscInt         *ids;
    8380:     PetscInt                field, Nc;
    8381:     const PetscInt         *comps;
    8382:     PetscVoidFn            *bvfunc;
    8383:     void                   *ctx;

    8385:     PetscCall(PetscDSGetBoundary(ds, b, &wf, &type, &name, &label, &numids, &ids, &field, &Nc, &comps, &bvfunc, NULL, &ctx));
    8386:     if (type == DM_BC_LOWER_BOUND || type == DM_BC_UPPER_BOUND) *hasBound = PETSC_TRUE;
    8387:   }
    8388:   PetscFunctionReturn(PETSC_SUCCESS);
    8389: }

    8391: /*@C
    8392:   DMProjectFunction - This projects the given function into the function space provided by a `DM`, putting the coefficients in a global vector.

    8394:   Collective

    8396:   Input Parameters:
    8397: + dm    - The `DM`
    8398: . time  - The time
    8399: . funcs - The coordinate functions to evaluate, one per field
    8400: . ctxs  - Optional array of contexts to pass to each coordinate function.  ctxs itself may be null.
    8401: - mode  - The insertion mode for values

    8403:   Output Parameter:
    8404: . X - vector

    8406:   Calling sequence of `funcs`:
    8407: + dim  - The spatial dimension
    8408: . time - The time at which to sample
    8409: . x    - The coordinates
    8410: . Nc   - The number of components
    8411: . u    - The output field values
    8412: - ctx  - optional function context

    8414:   Level: developer

    8416:   Developer Notes:
    8417:   This API is specific to only particular usage of `DM`

    8419:   The notes need to provide some information about what has to be provided to the `DM` to be able to perform the computation.

    8421: .seealso: [](ch_dmbase), `DM`, `DMProjectFunctionLocal()`, `DMProjectFunctionLabel()`, `DMComputeL2Diff()`
    8422: @*/
    8423: PetscErrorCode DMProjectFunction(DM dm, PetscReal time, PetscErrorCode (**funcs)(PetscInt dim, PetscReal time, const PetscReal x[], PetscInt Nc, PetscScalar *u, PetscCtx ctx), void **ctxs, InsertMode mode, Vec X)
    8424: {
    8425:   Vec localX;

    8427:   PetscFunctionBegin;
    8429:   PetscCall(PetscLogEventBegin(DM_ProjectFunction, dm, X, 0, 0));
    8430:   PetscCall(DMGetLocalVector(dm, &localX));
    8431:   PetscCall(VecSet(localX, 0.));
    8432:   PetscCall(DMProjectFunctionLocal(dm, time, funcs, ctxs, mode, localX));
    8433:   PetscCall(DMLocalToGlobalBegin(dm, localX, mode, X));
    8434:   PetscCall(DMLocalToGlobalEnd(dm, localX, mode, X));
    8435:   PetscCall(DMRestoreLocalVector(dm, &localX));
    8436:   PetscCall(PetscLogEventEnd(DM_ProjectFunction, dm, X, 0, 0));
    8437:   PetscFunctionReturn(PETSC_SUCCESS);
    8438: }

    8440: /*@C
    8441:   DMProjectFunctionLocal - This projects the given function into the function space provided by a `DM`, putting the coefficients in a local vector.

    8443:   Not Collective

    8445:   Input Parameters:
    8446: + dm    - The `DM`
    8447: . time  - The time
    8448: . funcs - The coordinate functions to evaluate, one per field
    8449: . ctxs  - Optional array of contexts to pass to each coordinate function.  ctxs itself may be null.
    8450: - mode  - The insertion mode for values

    8452:   Output Parameter:
    8453: . localX - vector

    8455:   Calling sequence of `funcs`:
    8456: + dim  - The spatial dimension
    8457: . time - The current timestep
    8458: . x    - The coordinates
    8459: . Nc   - The number of components
    8460: . u    - The output field values
    8461: - ctx  - optional function context

    8463:   Level: developer

    8465:   Developer Notes:
    8466:   This API is specific to only particular usage of `DM`

    8468:   The notes need to provide some information about what has to be provided to the `DM` to be able to perform the computation.

    8470: .seealso: [](ch_dmbase), `DM`, `DMProjectFunction()`, `DMProjectFunctionLabel()`, `DMComputeL2Diff()`
    8471: @*/
    8472: PetscErrorCode DMProjectFunctionLocal(DM dm, PetscReal time, PetscErrorCode (**funcs)(PetscInt dim, PetscReal time, const PetscReal x[], PetscInt Nc, PetscScalar *u, PetscCtx ctx), void **ctxs, InsertMode mode, Vec localX)
    8473: {
    8474:   PetscFunctionBegin;
    8477:   PetscUseTypeMethod(dm, projectfunctionlocal, time, funcs, ctxs, mode, localX);
    8478:   PetscFunctionReturn(PETSC_SUCCESS);
    8479: }

    8481: /*@C
    8482:   DMProjectFunctionLabel - This projects the given function into the function space provided by the `DM`, putting the coefficients in a global vector, setting values only for points in the given label.

    8484:   Collective

    8486:   Input Parameters:
    8487: + dm     - The `DM`
    8488: . time   - The time
    8489: . numIds - The number of ids
    8490: . ids    - The ids
    8491: . Nc     - The number of components
    8492: . comps  - The components
    8493: . label  - The `DMLabel` selecting the portion of the mesh for projection
    8494: . funcs  - The coordinate functions to evaluate, one per field
    8495: . ctxs   - Optional array of contexts to pass to each coordinate function.  ctxs may be null.
    8496: - mode   - The insertion mode for values

    8498:   Output Parameter:
    8499: . X - vector

    8501:   Calling sequence of `funcs`:
    8502: + dim  - The spatial dimension
    8503: . time - The current timestep
    8504: . x    - The coordinates
    8505: . Nc   - The number of components
    8506: . u    - The output field values
    8507: - ctx  - optional function context

    8509:   Level: developer

    8511:   Developer Notes:
    8512:   This API is specific to only particular usage of `DM`

    8514:   The notes need to provide some information about what has to be provided to the `DM` to be able to perform the computation.

    8516: .seealso: [](ch_dmbase), `DM`, `DMProjectFunction()`, `DMProjectFunctionLocal()`, `DMProjectFunctionLabelLocal()`, `DMComputeL2Diff()`
    8517: @*/
    8518: PetscErrorCode DMProjectFunctionLabel(DM dm, PetscReal time, DMLabel label, PetscInt numIds, const PetscInt ids[], PetscInt Nc, const PetscInt comps[], PetscErrorCode (**funcs)(PetscInt dim, PetscReal time, const PetscReal x[], PetscInt Nc, PetscScalar *u, PetscCtx ctx), void **ctxs, InsertMode mode, Vec X)
    8519: {
    8520:   Vec localX;

    8522:   PetscFunctionBegin;
    8524:   PetscCall(DMGetLocalVector(dm, &localX));
    8525:   PetscCall(VecSet(localX, 0.));
    8526:   PetscCall(DMProjectFunctionLabelLocal(dm, time, label, numIds, ids, Nc, comps, funcs, ctxs, mode, localX));
    8527:   PetscCall(DMLocalToGlobalBegin(dm, localX, mode, X));
    8528:   PetscCall(DMLocalToGlobalEnd(dm, localX, mode, X));
    8529:   PetscCall(DMRestoreLocalVector(dm, &localX));
    8530:   PetscFunctionReturn(PETSC_SUCCESS);
    8531: }

    8533: /*@C
    8534:   DMProjectFunctionLabelLocal - This projects the given function into the function space provided by the `DM`, putting the coefficients in a local vector, setting values only for points in the given label.

    8536:   Not Collective

    8538:   Input Parameters:
    8539: + dm     - The `DM`
    8540: . time   - The time
    8541: . label  - The `DMLabel` selecting the portion of the mesh for projection
    8542: . numIds - The number of ids
    8543: . ids    - The ids
    8544: . Nc     - The number of components
    8545: . comps  - The components
    8546: . funcs  - The coordinate functions to evaluate, one per field
    8547: . ctxs   - Optional array of contexts to pass to each coordinate function.  ctxs itself may be null.
    8548: - mode   - The insertion mode for values

    8550:   Output Parameter:
    8551: . localX - vector

    8553:   Calling sequence of `funcs`:
    8554: + dim  - The spatial dimension
    8555: . time - The current time
    8556: . x    - The coordinates
    8557: . Nc   - The number of components
    8558: . u    - The output field values
    8559: - ctx  - optional function context

    8561:   Level: developer

    8563:   Developer Notes:
    8564:   This API is specific to only particular usage of `DM`

    8566:   The notes need to provide some information about what has to be provided to the `DM` to be able to perform the computation.

    8568: .seealso: [](ch_dmbase), `DM`, `DMProjectFunction()`, `DMProjectFunctionLocal()`, `DMProjectFunctionLabel()`, `DMComputeL2Diff()`
    8569: @*/
    8570: PetscErrorCode DMProjectFunctionLabelLocal(DM dm, PetscReal time, DMLabel label, PetscInt numIds, const PetscInt ids[], PetscInt Nc, const PetscInt comps[], PetscErrorCode (**funcs)(PetscInt dim, PetscReal time, const PetscReal x[], PetscInt Nc, PetscScalar *u, PetscCtx ctx), void **ctxs, InsertMode mode, Vec localX)
    8571: {
    8572:   PetscFunctionBegin;
    8575:   PetscUseTypeMethod(dm, projectfunctionlabellocal, time, label, numIds, ids, Nc, comps, funcs, ctxs, mode, localX);
    8576:   PetscFunctionReturn(PETSC_SUCCESS);
    8577: }

    8579: /*@C
    8580:   DMProjectFieldLocal - This projects the given function of the input fields into the function space provided by the `DM`, putting the coefficients in a local vector.

    8582:   Not Collective

    8584:   Input Parameters:
    8585: + dm     - The `DM`
    8586: . time   - The time
    8587: . localU - The input field vector; may be `NULL` if projection is defined purely by coordinates
    8588: . funcs  - The functions to evaluate, one per field
    8589: - mode   - The insertion mode for values

    8591:   Output Parameter:
    8592: . localX - The output vector

    8594:   Calling sequence of `funcs`:
    8595: + dim          - The spatial dimension
    8596: . Nf           - The number of input fields
    8597: . NfAux        - The number of input auxiliary fields
    8598: . uOff         - The offset of each field in u[]
    8599: . uOff_x       - The offset of each field in u_x[]
    8600: . u            - The field values at this point in space
    8601: . u_t          - The field time derivative at this point in space (or `NULL`)
    8602: . u_x          - The field derivatives at this point in space
    8603: . aOff         - The offset of each auxiliary field in u[]
    8604: . aOff_x       - The offset of each auxiliary field in u_x[]
    8605: . a            - The auxiliary field values at this point in space
    8606: . a_t          - The auxiliary field time derivative at this point in space (or `NULL`)
    8607: . a_x          - The auxiliary field derivatives at this point in space
    8608: . t            - The current time
    8609: . x            - The coordinates of this point
    8610: . numConstants - The number of constants
    8611: . constants    - The value of each constant
    8612: - f            - The value of the function at this point in space

    8614:   Level: intermediate

    8616:   Note:
    8617:   There are three different `DM`s that potentially interact in this function. The output `DM`, dm, specifies the layout of the values calculates by funcs.
    8618:   The input `DM`, attached to U, may be different. For example, you can input the solution over the full domain, but output over a piece of the boundary, or
    8619:   a subdomain. You can also output a different number of fields than the input, with different discretizations. Last the auxiliary `DM`, attached to the
    8620:   auxiliary field vector, which is attached to dm, can also be different. It can have a different topology, number of fields, and discretizations.

    8622:   Developer Notes:
    8623:   This API is specific to only particular usage of `DM`

    8625:   The notes need to provide some information about what has to be provided to the `DM` to be able to perform the computation.

    8627: .seealso: [](ch_dmbase), `DM`, `DMProjectField()`, `DMProjectFieldLabelLocal()`,
    8628: `DMProjectFunction()`, `DMComputeL2Diff()`
    8629: @*/
    8630: PetscErrorCode DMProjectFieldLocal(DM dm, PetscReal time, Vec localU, void (**funcs)(PetscInt dim, PetscInt Nf, PetscInt NfAux, const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[], const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[], PetscReal t, const PetscReal x[], PetscInt numConstants, const PetscScalar constants[], PetscScalar f[]), InsertMode mode, Vec localX)
    8631: {
    8632:   PetscFunctionBegin;
    8636:   PetscUseTypeMethod(dm, projectfieldlocal, time, localU, funcs, mode, localX);
    8637:   PetscFunctionReturn(PETSC_SUCCESS);
    8638: }

    8640: /*@C
    8641:   DMProjectFieldLabelLocal - This projects the given function of the input fields into the function space provided, putting the coefficients in a local vector, calculating only over the portion of the domain specified by the label.

    8643:   Not Collective

    8645:   Input Parameters:
    8646: + dm     - The `DM`
    8647: . time   - The time
    8648: . label  - The `DMLabel` marking the portion of the domain to output
    8649: . numIds - The number of label ids to use
    8650: . ids    - The label ids to use for marking
    8651: . Nc     - The number of components to set in the output, or `PETSC_DETERMINE` for all components
    8652: . comps  - The components to set in the output, or `NULL` for all components
    8653: . localU - The input field vector
    8654: . funcs  - The functions to evaluate, one per field
    8655: - mode   - The insertion mode for values

    8657:   Output Parameter:
    8658: . localX - The output vector

    8660:   Calling sequence of `funcs`:
    8661: + dim          - The spatial dimension
    8662: . Nf           - The number of input fields
    8663: . NfAux        - The number of input auxiliary fields
    8664: . uOff         - The offset of each field in u[]
    8665: . uOff_x       - The offset of each field in u_x[]
    8666: . u            - The field values at this point in space
    8667: . u_t          - The field time derivative at this point in space (or `NULL`)
    8668: . u_x          - The field derivatives at this point in space
    8669: . aOff         - The offset of each auxiliary field in u[]
    8670: . aOff_x       - The offset of each auxiliary field in u_x[]
    8671: . a            - The auxiliary field values at this point in space
    8672: . a_t          - The auxiliary field time derivative at this point in space (or `NULL`)
    8673: . a_x          - The auxiliary field derivatives at this point in space
    8674: . t            - The current time
    8675: . x            - The coordinates of this point
    8676: . numConstants - The number of constants
    8677: . constants    - The value of each constant
    8678: - f            - The value of the function at this point in space

    8680:   Level: intermediate

    8682:   Note:
    8683:   There are three different `DM`s that potentially interact in this function. The output `DM`, dm, specifies the layout of the values calculates by funcs.
    8684:   The input `DM`, attached to localU, may be different. For example, you can input the solution over the full domain, but output over a piece of the boundary, or
    8685:   a subdomain. You can also output a different number of fields than the input, with different discretizations. Last the auxiliary `DM`, attached to the
    8686:   auxiliary field vector, which is attached to dm, can also be different. It can have a different topology, number of fields, and discretizations.

    8688:   Developer Notes:
    8689:   This API is specific to only particular usage of `DM`

    8691:   The notes need to provide some information about what has to be provided to the `DM` to be able to perform the computation.

    8693: .seealso: [](ch_dmbase), `DM`, `DMProjectField()`, `DMProjectFieldLabel()`, `DMProjectFunction()`, `DMComputeL2Diff()`
    8694: @*/
    8695: PetscErrorCode DMProjectFieldLabelLocal(DM dm, PetscReal time, DMLabel label, PetscInt numIds, const PetscInt ids[], PetscInt Nc, const PetscInt comps[], Vec localU, void (**funcs)(PetscInt dim, PetscInt Nf, PetscInt NfAux, const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[], const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[], PetscReal t, const PetscReal x[], PetscInt numConstants, const PetscScalar constants[], PetscScalar f[]), InsertMode mode, Vec localX)
    8696: {
    8697:   PetscFunctionBegin;
    8701:   PetscUseTypeMethod(dm, projectfieldlabellocal, time, label, numIds, ids, Nc, comps, localU, funcs, mode, localX);
    8702:   PetscFunctionReturn(PETSC_SUCCESS);
    8703: }

    8705: /*@C
    8706:   DMProjectFieldLabel - This projects the given function of the input fields into the function space provided, putting the coefficients in a global vector, calculating only over the portion of the domain specified by the label.

    8708:   Not Collective

    8710:   Input Parameters:
    8711: + dm     - The `DM`
    8712: . time   - The time
    8713: . label  - The `DMLabel` marking the portion of the domain to output
    8714: . numIds - The number of label ids to use
    8715: . ids    - The label ids to use for marking
    8716: . Nc     - The number of components to set in the output, or `PETSC_DETERMINE` for all components
    8717: . comps  - The components to set in the output, or `NULL` for all components
    8718: . U      - The input field vector
    8719: . funcs  - The functions to evaluate, one per field
    8720: - mode   - The insertion mode for values

    8722:   Output Parameter:
    8723: . X - The output vector

    8725:   Calling sequence of `funcs`:
    8726: + dim          - The spatial dimension
    8727: . Nf           - The number of input fields
    8728: . NfAux        - The number of input auxiliary fields
    8729: . uOff         - The offset of each field in u[]
    8730: . uOff_x       - The offset of each field in u_x[]
    8731: . u            - The field values at this point in space
    8732: . u_t          - The field time derivative at this point in space (or `NULL`)
    8733: . u_x          - The field derivatives at this point in space
    8734: . aOff         - The offset of each auxiliary field in u[]
    8735: . aOff_x       - The offset of each auxiliary field in u_x[]
    8736: . a            - The auxiliary field values at this point in space
    8737: . a_t          - The auxiliary field time derivative at this point in space (or `NULL`)
    8738: . a_x          - The auxiliary field derivatives at this point in space
    8739: . t            - The current time
    8740: . x            - The coordinates of this point
    8741: . numConstants - The number of constants
    8742: . constants    - The value of each constant
    8743: - f            - The value of the function at this point in space

    8745:   Level: intermediate

    8747:   Note:
    8748:   There are three different `DM`s that potentially interact in this function. The output `DM`, dm, specifies the layout of the values calculates by funcs.
    8749:   The input `DM`, attached to U, may be different. For example, you can input the solution over the full domain, but output over a piece of the boundary, or
    8750:   a subdomain. You can also output a different number of fields than the input, with different discretizations. Last the auxiliary `DM`, attached to the
    8751:   auxiliary field vector, which is attached to dm, can also be different. It can have a different topology, number of fields, and discretizations.

    8753:   Developer Notes:
    8754:   This API is specific to only particular usage of `DM`

    8756:   The notes need to provide some information about what has to be provided to the `DM` to be able to perform the computation.

    8758: .seealso: [](ch_dmbase), `DM`, `DMProjectField()`, `DMProjectFieldLabelLocal()`, `DMProjectFunction()`, `DMComputeL2Diff()`
    8759: @*/
    8760: PetscErrorCode DMProjectFieldLabel(DM dm, PetscReal time, DMLabel label, PetscInt numIds, const PetscInt ids[], PetscInt Nc, const PetscInt comps[], Vec U, void (**funcs)(PetscInt dim, PetscInt Nf, PetscInt NfAux, const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[], const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[], PetscReal t, const PetscReal x[], PetscInt numConstants, const PetscScalar constants[], PetscScalar f[]), InsertMode mode, Vec X)
    8761: {
    8762:   DM  dmIn;
    8763:   Vec localU, localX;

    8765:   PetscFunctionBegin;
    8767:   PetscCall(VecGetDM(U, &dmIn));
    8768:   PetscCall(DMGetLocalVector(dmIn, &localU));
    8769:   PetscCall(DMGetLocalVector(dm, &localX));
    8770:   PetscCall(VecSet(localX, 0.));
    8771:   PetscCall(DMGlobalToLocalBegin(dmIn, U, mode, localU));
    8772:   PetscCall(DMGlobalToLocalEnd(dmIn, U, mode, localU));
    8773:   PetscCall(DMProjectFieldLabelLocal(dm, time, label, numIds, ids, Nc, comps, localU, funcs, mode, localX));
    8774:   PetscCall(DMLocalToGlobalBegin(dm, localX, mode, X));
    8775:   PetscCall(DMLocalToGlobalEnd(dm, localX, mode, X));
    8776:   PetscCall(DMRestoreLocalVector(dm, &localX));
    8777:   PetscCall(DMRestoreLocalVector(dmIn, &localU));
    8778:   PetscFunctionReturn(PETSC_SUCCESS);
    8779: }

    8781: /*@C
    8782:   DMProjectBdFieldLabelLocal - This projects the given function of the input fields into the function space provided, putting the coefficients in a local vector, calculating only over the portion of the domain boundary specified by the label.

    8784:   Not Collective

    8786:   Input Parameters:
    8787: + dm     - The `DM`
    8788: . time   - The time
    8789: . label  - The `DMLabel` marking the portion of the domain boundary to output
    8790: . numIds - The number of label ids to use
    8791: . ids    - The label ids to use for marking
    8792: . Nc     - The number of components to set in the output, or `PETSC_DETERMINE` for all components
    8793: . comps  - The components to set in the output, or `NULL` for all components
    8794: . localU - The input field vector
    8795: . funcs  - The functions to evaluate, one per field
    8796: - mode   - The insertion mode for values

    8798:   Output Parameter:
    8799: . localX - The output vector

    8801:   Calling sequence of `funcs`:
    8802: + dim          - The spatial dimension
    8803: . Nf           - The number of input fields
    8804: . NfAux        - The number of input auxiliary fields
    8805: . uOff         - The offset of each field in u[]
    8806: . uOff_x       - The offset of each field in u_x[]
    8807: . u            - The field values at this point in space
    8808: . u_t          - The field time derivative at this point in space (or `NULL`)
    8809: . u_x          - The field derivatives at this point in space
    8810: . aOff         - The offset of each auxiliary field in u[]
    8811: . aOff_x       - The offset of each auxiliary field in u_x[]
    8812: . a            - The auxiliary field values at this point in space
    8813: . a_t          - The auxiliary field time derivative at this point in space (or `NULL`)
    8814: . a_x          - The auxiliary field derivatives at this point in space
    8815: . t            - The current time
    8816: . x            - The coordinates of this point
    8817: . n            - The face normal
    8818: . numConstants - The number of constants
    8819: . constants    - The value of each constant
    8820: - f            - The value of the function at this point in space

    8822:   Level: intermediate

    8824:   Note:
    8825:   There are three different `DM`s that potentially interact in this function. The output `DM`, dm, specifies the layout of the values calculates by funcs.
    8826:   The input `DM`, attached to U, may be different. For example, you can input the solution over the full domain, but output over a piece of the boundary, or
    8827:   a subdomain. You can also output a different number of fields than the input, with different discretizations. Last the auxiliary `DM`, attached to the
    8828:   auxiliary field vector, which is attached to dm, can also be different. It can have a different topology, number of fields, and discretizations.

    8830:   Developer Notes:
    8831:   This API is specific to only particular usage of `DM`

    8833:   The notes need to provide some information about what has to be provided to the `DM` to be able to perform the computation.

    8835: .seealso: [](ch_dmbase), `DM`, `DMProjectField()`, `DMProjectFieldLabelLocal()`, `DMProjectFunction()`, `DMComputeL2Diff()`
    8836: @*/
    8837: PetscErrorCode DMProjectBdFieldLabelLocal(DM dm, PetscReal time, DMLabel label, PetscInt numIds, const PetscInt ids[], PetscInt Nc, const PetscInt comps[], Vec localU, void (**funcs)(PetscInt dim, PetscInt Nf, PetscInt NfAux, const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[], const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[], PetscReal t, const PetscReal x[], const PetscReal n[], PetscInt numConstants, const PetscScalar constants[], PetscScalar f[]), InsertMode mode, Vec localX)
    8838: {
    8839:   PetscFunctionBegin;
    8843:   PetscUseTypeMethod(dm, projectbdfieldlabellocal, time, label, numIds, ids, Nc, comps, localU, funcs, mode, localX);
    8844:   PetscFunctionReturn(PETSC_SUCCESS);
    8845: }

    8847: /*@C
    8848:   DMComputeL2Diff - This function computes the L_2 difference between a function u and an FEM interpolant solution u_h.

    8850:   Collective

    8852:   Input Parameters:
    8853: + dm    - The `DM`
    8854: . time  - The time
    8855: . funcs - The functions to evaluate for each field component
    8856: . ctxs  - Optional array of contexts to pass to each function, or `NULL`.
    8857: - X     - The coefficient vector u_h, a global vector

    8859:   Output Parameter:
    8860: . diff - The diff ||u - u_h||_2

    8862:   Level: developer

    8864:   Developer Notes:
    8865:   This API is specific to only particular usage of `DM`

    8867:   The notes need to provide some information about what has to be provided to the `DM` to be able to perform the computation.

    8869: .seealso: [](ch_dmbase), `DM`, `DMProjectFunction()`, `DMComputeL2FieldDiff()`, `DMComputeL2GradientDiff()`
    8870: @*/
    8871: PetscErrorCode DMComputeL2Diff(DM dm, PetscReal time, PetscErrorCode (**funcs)(PetscInt, PetscReal, const PetscReal[], PetscInt, PetscScalar *, void *), void **ctxs, Vec X, PetscReal *diff)
    8872: {
    8873:   PetscFunctionBegin;
    8876:   PetscUseTypeMethod(dm, computel2diff, time, funcs, ctxs, X, diff);
    8877:   PetscFunctionReturn(PETSC_SUCCESS);
    8878: }

    8880: /*@C
    8881:   DMComputeL2GradientDiff - This function computes the L_2 difference between the gradient of a function u and an FEM interpolant solution grad u_h.

    8883:   Collective

    8885:   Input Parameters:
    8886: + dm    - The `DM`
    8887: . time  - The time
    8888: . funcs - The gradient functions to evaluate for each field component
    8889: . ctxs  - Optional array of contexts to pass to each function, or `NULL`.
    8890: . X     - The coefficient vector u_h, a global vector
    8891: - n     - The vector to project along

    8893:   Output Parameter:
    8894: . diff - The diff ||(grad u - grad u_h) . n||_2

    8896:   Level: developer

    8898:   Developer Notes:
    8899:   This API is specific to only particular usage of `DM`

    8901:   The notes need to provide some information about what has to be provided to the `DM` to be able to perform the computation.

    8903: .seealso: [](ch_dmbase), `DM`, `DMProjectFunction()`, `DMComputeL2Diff()`, `DMComputeL2FieldDiff()`
    8904: @*/
    8905: PetscErrorCode DMComputeL2GradientDiff(DM dm, PetscReal time, PetscErrorCode (**funcs)(PetscInt, PetscReal, const PetscReal[], const PetscReal[], PetscInt, PetscScalar *, void *), void **ctxs, Vec X, const PetscReal n[], PetscReal *diff)
    8906: {
    8907:   PetscFunctionBegin;
    8910:   PetscUseTypeMethod(dm, computel2gradientdiff, time, funcs, ctxs, X, n, diff);
    8911:   PetscFunctionReturn(PETSC_SUCCESS);
    8912: }

    8914: /*@C
    8915:   DMComputeL2FieldDiff - This function computes the L_2 difference between a function u and an FEM interpolant solution u_h, separated into field components.

    8917:   Collective

    8919:   Input Parameters:
    8920: + dm    - The `DM`
    8921: . time  - The time
    8922: . funcs - The functions to evaluate for each field component
    8923: . ctxs  - Optional array of contexts to pass to each function, or `NULL`.
    8924: - X     - The coefficient vector u_h, a global vector

    8926:   Output Parameter:
    8927: . diff - The array of differences, ||u^f - u^f_h||_2

    8929:   Level: developer

    8931:   Developer Notes:
    8932:   This API is specific to only particular usage of `DM`

    8934:   The notes need to provide some information about what has to be provided to the `DM` to be able to perform the computation.

    8936: .seealso: [](ch_dmbase), `DM`, `DMProjectFunction()`, `DMComputeL2GradientDiff()`
    8937: @*/
    8938: PetscErrorCode DMComputeL2FieldDiff(DM dm, PetscReal time, PetscErrorCode (**funcs)(PetscInt, PetscReal, const PetscReal[], PetscInt, PetscScalar *, void *), void **ctxs, Vec X, PetscReal diff[])
    8939: {
    8940:   PetscFunctionBegin;
    8943:   PetscUseTypeMethod(dm, computel2fielddiff, time, funcs, ctxs, X, diff);
    8944:   PetscFunctionReturn(PETSC_SUCCESS);
    8945: }

    8947: /*@C
    8948:   DMGetNeighbors - Gets an array containing the MPI ranks of all the processes neighbors

    8950:   Not Collective

    8952:   Input Parameter:
    8953: . dm - The `DM`

    8955:   Output Parameters:
    8956: + nranks - the number of neighbours
    8957: - ranks  - the neighbors ranks

    8959:   Level: beginner

    8961:   Note:
    8962:   Do not free the array, it is freed when the `DM` is destroyed.

    8964: .seealso: [](ch_dmbase), `DM`, `DMDAGetNeighbors()`, `PetscSFGetRootRanks()`
    8965: @*/
    8966: PetscErrorCode DMGetNeighbors(DM dm, PetscInt *nranks, const PetscMPIInt *ranks[])
    8967: {
    8968:   PetscFunctionBegin;
    8970:   PetscUseTypeMethod(dm, getneighbors, nranks, ranks);
    8971:   PetscFunctionReturn(PETSC_SUCCESS);
    8972: }

    8974: #include <petsc/private/matimpl.h>

    8976: /*
    8977:     Converts the input vector to a ghosted vector and then calls the standard coloring code.
    8978:     This must be a different function because it requires DM which is not defined in the Mat library
    8979: */
    8980: static PetscErrorCode MatFDColoringApply_AIJDM(Mat J, MatFDColoring coloring, Vec x1, void *sctx)
    8981: {
    8982:   PetscFunctionBegin;
    8983:   if (coloring->ctype == IS_COLORING_LOCAL) {
    8984:     Vec x1local;
    8985:     DM  dm;
    8986:     PetscCall(MatGetDM(J, &dm));
    8987:     PetscCheck(dm, PetscObjectComm((PetscObject)J), PETSC_ERR_ARG_INCOMP, "IS_COLORING_LOCAL requires a DM");
    8988:     PetscCall(DMGetLocalVector(dm, &x1local));
    8989:     PetscCall(DMGlobalToLocalBegin(dm, x1, INSERT_VALUES, x1local));
    8990:     PetscCall(DMGlobalToLocalEnd(dm, x1, INSERT_VALUES, x1local));
    8991:     x1 = x1local;
    8992:   }
    8993:   PetscCall(MatFDColoringApply_AIJ(J, coloring, x1, sctx));
    8994:   if (coloring->ctype == IS_COLORING_LOCAL) {
    8995:     DM dm;
    8996:     PetscCall(MatGetDM(J, &dm));
    8997:     PetscCall(DMRestoreLocalVector(dm, &x1));
    8998:   }
    8999:   PetscFunctionReturn(PETSC_SUCCESS);
    9000: }

    9002: /*@
    9003:   MatFDColoringUseDM - allows a `MatFDColoring` object to use the `DM` associated with the matrix to compute a `IS_COLORING_LOCAL` coloring

    9005:   Input Parameters:
    9006: + coloring   - The matrix to get the `DM` from
    9007: - fdcoloring - the `MatFDColoring` object

    9009:   Level: advanced

    9011:   Developer Note:
    9012:   This routine exists because the PETSc `Mat` library does not know about the `DM` objects

    9014: .seealso: [](ch_dmbase), `DM`, `MatFDColoring`, `MatFDColoringCreate()`, `ISColoringType`
    9015: @*/
    9016: PetscErrorCode MatFDColoringUseDM(Mat coloring, MatFDColoring fdcoloring)
    9017: {
    9018:   PetscFunctionBegin;
    9019:   coloring->ops->fdcoloringapply = MatFDColoringApply_AIJDM;
    9020:   PetscFunctionReturn(PETSC_SUCCESS);
    9021: }

    9023: /*@
    9024:   DMGetCompatibility - determine if two `DM`s are compatible

    9026:   Collective

    9028:   Input Parameters:
    9029: + dm1 - the first `DM`
    9030: - dm2 - the second `DM`

    9032:   Output Parameters:
    9033: + compatible - whether or not the two `DM`s are compatible
    9034: - set        - whether or not the compatible value was actually determined and set

    9036:   Level: advanced

    9038:   Notes:
    9039:   Two `DM`s are deemed compatible if they represent the same parallel decomposition
    9040:   of the same topology. This implies that the section (field data) on one
    9041:   "makes sense" with respect to the topology and parallel decomposition of the other.
    9042:   Loosely speaking, compatible `DM`s represent the same domain and parallel
    9043:   decomposition, but hold different data.

    9045:   Typically, one would confirm compatibility if intending to simultaneously iterate
    9046:   over a pair of vectors obtained from different `DM`s.

    9048:   For example, two `DMDA` objects are compatible if they have the same local
    9049:   and global sizes and the same stencil width. They can have different numbers
    9050:   of degrees of freedom per node. Thus, one could use the node numbering from
    9051:   either `DM` in bounds for a loop over vectors derived from either `DM`.

    9053:   Consider the operation of summing data living on a 2-dof `DMDA` to data living
    9054:   on a 1-dof `DMDA`, which should be compatible, as in the following snippet.
    9055: .vb
    9056:   ...
    9057:   PetscCall(DMGetCompatibility(da1,da2,&compatible,&set));
    9058:   if (set && compatible)  {
    9059:     PetscCall(DMDAVecGetArrayDOF(da1,vec1,&arr1));
    9060:     PetscCall(DMDAVecGetArrayDOF(da2,vec2,&arr2));
    9061:     PetscCall(DMDAGetCorners(da1,&x,&y,NULL,&m,&n,NULL));
    9062:     for (j=y; j<y+n; ++j) {
    9063:       for (i=x; i<x+m, ++i) {
    9064:         arr1[j][i][0] = arr2[j][i][0] + arr2[j][i][1];
    9065:       }
    9066:     }
    9067:     PetscCall(DMDAVecRestoreArrayDOF(da1,vec1,&arr1));
    9068:     PetscCall(DMDAVecRestoreArrayDOF(da2,vec2,&arr2));
    9069:   } else {
    9070:     SETERRQ(PetscObjectComm((PetscObject)da1,PETSC_ERR_ARG_INCOMP,"DMDA objects incompatible");
    9071:   }
    9072:   ...
    9073: .ve

    9075:   Checking compatibility might be expensive for a given implementation of `DM`,
    9076:   or might be impossible to unambiguously confirm or deny. For this reason,
    9077:   this function may decline to determine compatibility, and hence users should
    9078:   always check the "set" output parameter.

    9080:   A `DM` is always compatible with itself.

    9082:   In the current implementation, `DM`s which live on "unequal" communicators
    9083:   (MPI_UNEQUAL in the terminology of MPI_Comm_compare()) are always deemed
    9084:   incompatible.

    9086:   This function is labeled "Collective," as information about all subdomains
    9087:   is required on each rank. However, in `DM` implementations which store all this
    9088:   information locally, this function may be merely "Logically Collective".

    9090:   Developer Note:
    9091:   Compatibility is assumed to be a symmetric concept; `DM` A is compatible with `DM` B
    9092:   iff B is compatible with A. Thus, this function checks the implementations
    9093:   of both dm and dmc (if they are of different types), attempting to determine
    9094:   compatibility. It is left to `DM` implementers to ensure that symmetry is
    9095:   preserved. The simplest way to do this is, when implementing type-specific
    9096:   logic for this function, is to check for existing logic in the implementation
    9097:   of other `DM` types and let *set = PETSC_FALSE if found.

    9099: .seealso: [](ch_dmbase), `DM`, `DMDACreateCompatibleDMDA()`, `DMStagCreateCompatibleDMStag()`
    9100: @*/
    9101: PetscErrorCode DMGetCompatibility(DM dm1, DM dm2, PetscBool *compatible, PetscBool *set)
    9102: {
    9103:   PetscMPIInt compareResult;
    9104:   DMType      type, type2;
    9105:   PetscBool   sameType;

    9107:   PetscFunctionBegin;

    9111:   /* Declare a DM compatible with itself */
    9112:   if (dm1 == dm2) {
    9113:     *set        = PETSC_TRUE;
    9114:     *compatible = PETSC_TRUE;
    9115:     PetscFunctionReturn(PETSC_SUCCESS);
    9116:   }

    9118:   /* Declare a DM incompatible with a DM that lives on an "unequal"
    9119:      communicator. Note that this does not preclude compatibility with
    9120:      DMs living on "congruent" or "similar" communicators, but this must be
    9121:      determined by the implementation-specific logic */
    9122:   PetscCallMPI(MPI_Comm_compare(PetscObjectComm((PetscObject)dm1), PetscObjectComm((PetscObject)dm2), &compareResult));
    9123:   if (compareResult == MPI_UNEQUAL) {
    9124:     *set        = PETSC_TRUE;
    9125:     *compatible = PETSC_FALSE;
    9126:     PetscFunctionReturn(PETSC_SUCCESS);
    9127:   }

    9129:   /* Pass to the implementation-specific routine, if one exists. */
    9130:   if (dm1->ops->getcompatibility) {
    9131:     PetscUseTypeMethod(dm1, getcompatibility, dm2, compatible, set);
    9132:     if (*set) PetscFunctionReturn(PETSC_SUCCESS);
    9133:   }

    9135:   /* If dm1 and dm2 are of different types, then attempt to check compatibility
    9136:      with an implementation of this function from dm2 */
    9137:   PetscCall(DMGetType(dm1, &type));
    9138:   PetscCall(DMGetType(dm2, &type2));
    9139:   PetscCall(PetscStrcmp(type, type2, &sameType));
    9140:   if (!sameType && dm2->ops->getcompatibility) {
    9141:     PetscUseTypeMethod(dm2, getcompatibility, dm1, compatible, set); /* Note argument order */
    9142:   } else {
    9143:     *set = PETSC_FALSE;
    9144:   }
    9145:   PetscFunctionReturn(PETSC_SUCCESS);
    9146: }

    9148: /*@C
    9149:   DMMonitorSet - Sets an additional monitor function that is to be used after a solve to monitor discretization performance.

    9151:   Logically Collective

    9153:   Input Parameters:
    9154: + dm             - the `DM`
    9155: . f              - the monitor function
    9156: . mctx           - [optional] context for private data for the monitor routine (use `NULL` if no context is desired)
    9157: - monitordestroy - [optional] routine that frees monitor context (may be `NULL`), see `PetscCtxDestroyFn` for the calling sequence

    9159:   Options Database Key:
    9160: . -dm_monitor_cancel - cancels all monitors that have been hardwired into a code by calls to `DMMonitorSet()`, but
    9161:                        does not cancel those set via the options database.

    9163:   Level: intermediate

    9165:   Note:
    9166:   Several different monitoring routines may be set by calling
    9167:   `DMMonitorSet()` multiple times or with `DMMonitorSetFromOptions()`; all will be called in the
    9168:   order in which they were set.

    9170:   Fortran Note:
    9171:   Only a single monitor function can be set for each `DM` object

    9173:   Developer Note:
    9174:   This API has a generic name but seems specific to a very particular aspect of the use of `DM`

    9176: .seealso: [](ch_dmbase), `DM`, `DMMonitorCancel()`, `DMMonitorSetFromOptions()`, `DMMonitor()`, `PetscCtxDestroyFn`
    9177: @*/
    9178: PetscErrorCode DMMonitorSet(DM dm, PetscErrorCode (*f)(DM, void *), void *mctx, PetscCtxDestroyFn *monitordestroy)
    9179: {
    9180:   PetscFunctionBegin;
    9182:   for (PetscInt m = 0; m < dm->numbermonitors; ++m) {
    9183:     PetscBool identical;

    9185:     PetscCall(PetscMonitorCompare((PetscErrorCode (*)(void))(PetscVoidFn *)f, mctx, monitordestroy, (PetscErrorCode (*)(void))(PetscVoidFn *)dm->monitor[m], dm->monitorcontext[m], dm->monitordestroy[m], &identical));
    9186:     if (identical) PetscFunctionReturn(PETSC_SUCCESS);
    9187:   }
    9188:   PetscCheck(dm->numbermonitors < MAXDMMONITORS, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Too many monitors set");
    9189:   dm->monitor[dm->numbermonitors]          = f;
    9190:   dm->monitordestroy[dm->numbermonitors]   = monitordestroy;
    9191:   dm->monitorcontext[dm->numbermonitors++] = mctx;
    9192:   PetscFunctionReturn(PETSC_SUCCESS);
    9193: }

    9195: /*@
    9196:   DMMonitorCancel - Clears all the monitor functions for a `DM` object.

    9198:   Logically Collective

    9200:   Input Parameter:
    9201: . dm - the DM

    9203:   Options Database Key:
    9204: . -dm_monitor_cancel - cancels all monitors that have been hardwired
    9205:   into a code by calls to `DMonitorSet()`, but does not cancel those
    9206:   set via the options database

    9208:   Level: intermediate

    9210:   Note:
    9211:   There is no way to clear one specific monitor from a `DM` object.

    9213: .seealso: [](ch_dmbase), `DM`, `DMMonitorSet()`, `DMMonitorSetFromOptions()`, `DMMonitor()`
    9214: @*/
    9215: PetscErrorCode DMMonitorCancel(DM dm)
    9216: {
    9217:   PetscInt m;

    9219:   PetscFunctionBegin;
    9221:   for (m = 0; m < dm->numbermonitors; ++m) {
    9222:     if (dm->monitordestroy[m]) PetscCall((*dm->monitordestroy[m])(&dm->monitorcontext[m]));
    9223:   }
    9224:   dm->numbermonitors = 0;
    9225:   PetscFunctionReturn(PETSC_SUCCESS);
    9226: }

    9228: /*@C
    9229:   DMMonitorSetFromOptions - Sets a monitor function and viewer appropriate for the type indicated by the user

    9231:   Collective

    9233:   Input Parameters:
    9234: + dm           - `DM` object you wish to monitor
    9235: . name         - the monitor type one is seeking
    9236: . help         - message indicating what monitoring is done
    9237: . manual       - manual page for the monitor
    9238: . monitor      - the monitor function, this must use a `PetscViewerFormat` as its context
    9239: - monitorsetup - a function that is called once ONLY if the user selected this monitor that may set additional features of the `DM` or `PetscViewer` objects

    9241:   Output Parameter:
    9242: . flg - Flag set if the monitor was created

    9244:   Calling sequence of `monitor`:
    9245: + dm  - the `DM` to be monitored
    9246: - ctx - monitor context

    9248:   Calling sequence of `monitorsetup`:
    9249: + dm - the `DM` to be monitored
    9250: - vf - the `PetscViewer` and format to be used by the monitor

    9252:   Level: developer

    9254: .seealso: [](ch_dmbase), `DM`, `PetscOptionsCreateViewer()`, `PetscOptionsGetReal()`, `PetscOptionsHasName()`, `PetscOptionsGetString()`,
    9255:           `PetscOptionsGetIntArray()`, `PetscOptionsGetRealArray()`, `PetscOptionsBool()`,
    9256:           `PetscOptionsInt()`, `PetscOptionsString()`, `PetscOptionsReal()`,
    9257:           `PetscOptionsName()`, `PetscOptionsBegin()`, `PetscOptionsEnd()`, `PetscOptionsHeadBegin()`,
    9258:           `PetscOptionsStringArray()`, `PetscOptionsRealArray()`, `PetscOptionsScalar()`,
    9259:           `PetscOptionsBoolGroupBegin()`, `PetscOptionsBoolGroup()`, `PetscOptionsBoolGroupEnd()`,
    9260:           `PetscOptionsFList()`, `PetscOptionsEList()`, `DMMonitor()`, `DMMonitorSet()`
    9261: @*/
    9262: PetscErrorCode DMMonitorSetFromOptions(DM dm, const char name[], const char help[], const char manual[], PetscErrorCode (*monitor)(DM dm, PetscCtx ctx), PetscErrorCode (*monitorsetup)(DM dm, PetscViewerAndFormat *vf), PetscBool *flg)
    9263: {
    9264:   PetscViewer       viewer;
    9265:   PetscViewerFormat format;

    9267:   PetscFunctionBegin;
    9269:   PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)dm), ((PetscObject)dm)->options, ((PetscObject)dm)->prefix, name, &viewer, &format, flg));
    9270:   if (*flg) {
    9271:     PetscViewerAndFormat *vf;

    9273:     PetscCall(PetscViewerAndFormatCreate(viewer, format, &vf));
    9274:     PetscCall(PetscViewerDestroy(&viewer));
    9275:     if (monitorsetup) PetscCall((*monitorsetup)(dm, vf));
    9276:     PetscCall(DMMonitorSet(dm, monitor, vf, (PetscCtxDestroyFn *)PetscViewerAndFormatDestroy));
    9277:   }
    9278:   PetscFunctionReturn(PETSC_SUCCESS);
    9279: }

    9281: /*@
    9282:   DMMonitor - runs the user provided monitor routines, if they exist

    9284:   Collective

    9286:   Input Parameter:
    9287: . dm - The `DM`

    9289:   Level: developer

    9291:   Developer Note:
    9292:   Note should indicate when during the life of the `DM` the monitor is run. It appears to be
    9293:   related to the discretization process seems rather specialized since some `DM` have no
    9294:   concept of discretization.

    9296: .seealso: [](ch_dmbase), `DM`, `DMMonitorSet()`, `DMMonitorSetFromOptions()`
    9297: @*/
    9298: PetscErrorCode DMMonitor(DM dm)
    9299: {
    9300:   PetscInt m;

    9302:   PetscFunctionBegin;
    9303:   if (!dm) PetscFunctionReturn(PETSC_SUCCESS);
    9305:   for (m = 0; m < dm->numbermonitors; ++m) PetscCall((*dm->monitor[m])(dm, dm->monitorcontext[m]));
    9306:   PetscFunctionReturn(PETSC_SUCCESS);
    9307: }

    9309: /*@
    9310:   DMComputeError - Computes the error assuming the user has provided the exact solution functions

    9312:   Collective

    9314:   Input Parameters:
    9315: + dm  - The `DM`
    9316: - sol - The solution vector

    9318:   Input/Output Parameter:
    9319: . errors - An array of length Nf, the number of fields, or `NULL` for no output; on output
    9320:            contains the error in each field

    9322:   Output Parameter:
    9323: . errorVec - A vector to hold the cellwise error (may be `NULL`)

    9325:   Level: developer

    9327:   Note:
    9328:   The exact solutions come from the `PetscDS` object, and the time comes from `DMGetOutputSequenceNumber()`.

    9330: .seealso: [](ch_dmbase), `DM`, `DMMonitorSet()`, `DMGetRegionNumDS()`, `PetscDSGetExactSolution()`, `DMGetOutputSequenceNumber()`
    9331: @*/
    9332: PetscErrorCode DMComputeError(DM dm, Vec sol, PetscReal errors[], Vec *errorVec)
    9333: {
    9334:   PetscErrorCode (**exactSol)(PetscInt, PetscReal, const PetscReal[], PetscInt, PetscScalar[], void *);
    9335:   void    **ctxs;
    9336:   PetscReal time;
    9337:   PetscInt  Nf, f, Nds, s;

    9339:   PetscFunctionBegin;
    9340:   PetscCall(DMGetNumFields(dm, &Nf));
    9341:   PetscCall(PetscCalloc2(Nf, &exactSol, Nf, &ctxs));
    9342:   PetscCall(DMGetNumDS(dm, &Nds));
    9343:   for (s = 0; s < Nds; ++s) {
    9344:     PetscDS         ds;
    9345:     DMLabel         label;
    9346:     IS              fieldIS;
    9347:     const PetscInt *fields;
    9348:     PetscInt        dsNf;

    9350:     PetscCall(DMGetRegionNumDS(dm, s, &label, &fieldIS, &ds, NULL));
    9351:     PetscCall(PetscDSGetNumFields(ds, &dsNf));
    9352:     if (fieldIS) PetscCall(ISGetIndices(fieldIS, &fields));
    9353:     for (f = 0; f < dsNf; ++f) {
    9354:       const PetscInt field = fields[f];
    9355:       PetscCall(PetscDSGetExactSolution(ds, field, &exactSol[field], &ctxs[field]));
    9356:     }
    9357:     if (fieldIS) PetscCall(ISRestoreIndices(fieldIS, &fields));
    9358:   }
    9359:   for (f = 0; f < Nf; ++f) PetscCheck(exactSol[f], PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_WRONG, "DS must contain exact solution functions in order to calculate error, missing for field %" PetscInt_FMT, f);
    9360:   PetscCall(DMGetOutputSequenceNumber(dm, NULL, &time));
    9361:   if (errors) PetscCall(DMComputeL2FieldDiff(dm, time, exactSol, ctxs, sol, errors));
    9362:   if (errorVec) {
    9363:     DM             edm;
    9364:     DMPolytopeType ct;
    9365:     PetscBool      simplex;
    9366:     PetscInt       dim, cStart, Nf;

    9368:     PetscCall(DMClone(dm, &edm));
    9369:     PetscCall(DMGetDimension(edm, &dim));
    9370:     PetscCall(DMPlexGetHeightStratum(dm, 0, &cStart, NULL));
    9371:     PetscCall(DMPlexGetCellType(dm, cStart, &ct));
    9372:     simplex = DMPolytopeTypeGetNumVertices(ct) == DMPolytopeTypeGetDim(ct) + 1 ? PETSC_TRUE : PETSC_FALSE;
    9373:     PetscCall(DMGetNumFields(dm, &Nf));
    9374:     for (f = 0; f < Nf; ++f) {
    9375:       PetscFE         fe, efe;
    9376:       PetscQuadrature q;
    9377:       const char     *name;

    9379:       PetscCall(DMGetField(dm, f, NULL, (PetscObject *)&fe));
    9380:       PetscCall(PetscFECreateLagrange(PETSC_COMM_SELF, dim, Nf, simplex, 0, PETSC_DETERMINE, &efe));
    9381:       PetscCall(PetscObjectGetName((PetscObject)fe, &name));
    9382:       PetscCall(PetscObjectSetName((PetscObject)efe, name));
    9383:       PetscCall(PetscFEGetQuadrature(fe, &q));
    9384:       PetscCall(PetscFESetQuadrature(efe, q));
    9385:       PetscCall(DMSetField(edm, f, NULL, (PetscObject)efe));
    9386:       PetscCall(PetscFEDestroy(&efe));
    9387:     }
    9388:     PetscCall(DMCreateDS(edm));

    9390:     PetscCall(DMCreateGlobalVector(edm, errorVec));
    9391:     PetscCall(PetscObjectSetName((PetscObject)*errorVec, "Error"));
    9392:     PetscCall(DMPlexComputeL2DiffVec(dm, time, exactSol, ctxs, sol, *errorVec));
    9393:     PetscCall(DMDestroy(&edm));
    9394:   }
    9395:   PetscCall(PetscFree2(exactSol, ctxs));
    9396:   PetscFunctionReturn(PETSC_SUCCESS);
    9397: }

    9399: /*@
    9400:   DMGetNumAuxiliaryVec - Get the number of auxiliary vectors associated with this `DM`

    9402:   Not Collective

    9404:   Input Parameter:
    9405: . dm - The `DM`

    9407:   Output Parameter:
    9408: . numAux - The number of auxiliary data vectors

    9410:   Level: advanced

    9412: .seealso: [](ch_dmbase), `DM`, `DMClearAuxiliaryVec()`, `DMSetAuxiliaryVec()`, `DMGetAuxiliaryLabels()`, `DMGetAuxiliaryVec()`
    9413: @*/
    9414: PetscErrorCode DMGetNumAuxiliaryVec(DM dm, PetscInt *numAux)
    9415: {
    9416:   PetscFunctionBegin;
    9418:   PetscCall(PetscHMapAuxGetSize(dm->auxData, numAux));
    9419:   PetscFunctionReturn(PETSC_SUCCESS);
    9420: }

    9422: /*@
    9423:   DMGetAuxiliaryVec - Get the auxiliary vector for region specified by the given label and value, and equation part

    9425:   Not Collective

    9427:   Input Parameters:
    9428: + dm    - The `DM`
    9429: . label - The `DMLabel`
    9430: . value - The label value indicating the region
    9431: - part  - The equation part, or 0 if unused

    9433:   Output Parameter:
    9434: . aux - The `Vec` holding auxiliary field data

    9436:   Level: advanced

    9438:   Note:
    9439:   If no auxiliary vector is found for this (label, value), (`NULL`, 0, 0) is checked as well.

    9441: .seealso: [](ch_dmbase), `DM`, `DMClearAuxiliaryVec()`, `DMSetAuxiliaryVec()`, `DMGetNumAuxiliaryVec()`, `DMGetAuxiliaryLabels()`
    9442: @*/
    9443: PetscErrorCode DMGetAuxiliaryVec(DM dm, DMLabel label, PetscInt value, PetscInt part, Vec *aux)
    9444: {
    9445:   PetscHashAuxKey key, wild = {NULL, 0, 0};
    9446:   PetscBool       has;

    9448:   PetscFunctionBegin;
    9451:   key.label = label;
    9452:   key.value = value;
    9453:   key.part  = part;
    9454:   PetscCall(PetscHMapAuxHas(dm->auxData, key, &has));
    9455:   if (has) PetscCall(PetscHMapAuxGet(dm->auxData, key, aux));
    9456:   else PetscCall(PetscHMapAuxGet(dm->auxData, wild, aux));
    9457:   PetscFunctionReturn(PETSC_SUCCESS);
    9458: }

    9460: /*@
    9461:   DMSetAuxiliaryVec - Set an auxiliary vector for region specified by the given label and value, and equation part

    9463:   Not Collective because auxiliary vectors are not parallel

    9465:   Input Parameters:
    9466: + dm    - The `DM`
    9467: . label - The `DMLabel`
    9468: . value - The label value indicating the region
    9469: . part  - The equation part, or 0 if unused
    9470: - aux   - The `Vec` holding auxiliary field data

    9472:   Level: advanced

    9474: .seealso: [](ch_dmbase), `DM`, `DMClearAuxiliaryVec()`, `DMGetAuxiliaryVec()`, `DMGetAuxiliaryLabels()`, `DMCopyAuxiliaryVec()`
    9475: @*/
    9476: PetscErrorCode DMSetAuxiliaryVec(DM dm, DMLabel label, PetscInt value, PetscInt part, Vec aux)
    9477: {
    9478:   Vec             old;
    9479:   PetscHashAuxKey key;

    9481:   PetscFunctionBegin;
    9484:   key.label = label;
    9485:   key.value = value;
    9486:   key.part  = part;
    9487:   PetscCall(PetscHMapAuxGet(dm->auxData, key, &old));
    9488:   PetscCall(PetscObjectReference((PetscObject)aux));
    9489:   if (!aux) PetscCall(PetscHMapAuxDel(dm->auxData, key));
    9490:   else PetscCall(PetscHMapAuxSet(dm->auxData, key, aux));
    9491:   PetscCall(VecDestroy(&old));
    9492:   PetscFunctionReturn(PETSC_SUCCESS);
    9493: }

    9495: /*@
    9496:   DMGetAuxiliaryLabels - Get the labels, values, and parts for all auxiliary vectors in this `DM`

    9498:   Not Collective

    9500:   Input Parameter:
    9501: . dm - The `DM`

    9503:   Output Parameters:
    9504: + labels - The `DMLabel`s for each `Vec`
    9505: . values - The label values for each `Vec`
    9506: - parts  - The equation parts for each `Vec`

    9508:   Level: advanced

    9510:   Note:
    9511:   The arrays passed in must be at least as large as `DMGetNumAuxiliaryVec()`.

    9513: .seealso: [](ch_dmbase), `DM`, `DMClearAuxiliaryVec()`, `DMGetNumAuxiliaryVec()`, `DMGetAuxiliaryVec()`, `DMSetAuxiliaryVec()`, `DMCopyAuxiliaryVec()`
    9514: @*/
    9515: PetscErrorCode DMGetAuxiliaryLabels(DM dm, DMLabel labels[], PetscInt values[], PetscInt parts[])
    9516: {
    9517:   PetscHashAuxKey *keys;
    9518:   PetscInt         n, i, off = 0;

    9520:   PetscFunctionBegin;
    9522:   PetscAssertPointer(labels, 2);
    9523:   PetscAssertPointer(values, 3);
    9524:   PetscAssertPointer(parts, 4);
    9525:   PetscCall(DMGetNumAuxiliaryVec(dm, &n));
    9526:   PetscCall(PetscMalloc1(n, &keys));
    9527:   PetscCall(PetscHMapAuxGetKeys(dm->auxData, &off, keys));
    9528:   for (i = 0; i < n; ++i) {
    9529:     labels[i] = keys[i].label;
    9530:     values[i] = keys[i].value;
    9531:     parts[i]  = keys[i].part;
    9532:   }
    9533:   PetscCall(PetscFree(keys));
    9534:   PetscFunctionReturn(PETSC_SUCCESS);
    9535: }

    9537: /*@
    9538:   DMCopyAuxiliaryVec - Copy the auxiliary vector data on a `DM` to a new `DM`

    9540:   Not Collective

    9542:   Input Parameter:
    9543: . dm - The `DM`

    9545:   Output Parameter:
    9546: . dmNew - The new `DM`, now with the same auxiliary data

    9548:   Level: advanced

    9550:   Note:
    9551:   This is a shallow copy of the auxiliary vectors

    9553: .seealso: [](ch_dmbase), `DM`, `DMClearAuxiliaryVec()`, `DMGetNumAuxiliaryVec()`, `DMGetAuxiliaryVec()`, `DMSetAuxiliaryVec()`
    9554: @*/
    9555: PetscErrorCode DMCopyAuxiliaryVec(DM dm, DM dmNew)
    9556: {
    9557:   PetscFunctionBegin;
    9560:   if (dm == dmNew) PetscFunctionReturn(PETSC_SUCCESS);
    9561:   PetscCall(DMClearAuxiliaryVec(dmNew));

    9563:   PetscCall(PetscHMapAuxDestroy(&dmNew->auxData));
    9564:   PetscCall(PetscHMapAuxDuplicate(dm->auxData, &dmNew->auxData));
    9565:   {
    9566:     Vec     *auxData;
    9567:     PetscInt n, i, off = 0;

    9569:     PetscCall(PetscHMapAuxGetSize(dmNew->auxData, &n));
    9570:     PetscCall(PetscMalloc1(n, &auxData));
    9571:     PetscCall(PetscHMapAuxGetVals(dmNew->auxData, &off, auxData));
    9572:     for (i = 0; i < n; ++i) PetscCall(PetscObjectReference((PetscObject)auxData[i]));
    9573:     PetscCall(PetscFree(auxData));
    9574:   }
    9575:   PetscFunctionReturn(PETSC_SUCCESS);
    9576: }

    9578: /*@
    9579:   DMClearAuxiliaryVec - Destroys the auxiliary vector information and creates a new empty one

    9581:   Not Collective

    9583:   Input Parameter:
    9584: . dm - The `DM`

    9586:   Level: advanced

    9588: .seealso: [](ch_dmbase), `DM`, `DMCopyAuxiliaryVec()`, `DMGetNumAuxiliaryVec()`, `DMGetAuxiliaryVec()`, `DMSetAuxiliaryVec()`
    9589: @*/
    9590: PetscErrorCode DMClearAuxiliaryVec(DM dm)
    9591: {
    9592:   Vec     *auxData;
    9593:   PetscInt n, i, off = 0;

    9595:   PetscFunctionBegin;
    9596:   PetscCall(PetscHMapAuxGetSize(dm->auxData, &n));
    9597:   PetscCall(PetscMalloc1(n, &auxData));
    9598:   PetscCall(PetscHMapAuxGetVals(dm->auxData, &off, auxData));
    9599:   for (i = 0; i < n; ++i) PetscCall(VecDestroy(&auxData[i]));
    9600:   PetscCall(PetscFree(auxData));
    9601:   PetscCall(PetscHMapAuxDestroy(&dm->auxData));
    9602:   PetscCall(PetscHMapAuxCreate(&dm->auxData));
    9603:   PetscFunctionReturn(PETSC_SUCCESS);
    9604: }

    9606: /*@
    9607:   DMPolytopeMatchOrientation - Determine an orientation (transformation) that takes the source face arrangement to the target face arrangement

    9609:   Not Collective

    9611:   Input Parameters:
    9612: + ct         - The `DMPolytopeType`
    9613: . sourceCone - The source arrangement of faces
    9614: - targetCone - The target arrangement of faces

    9616:   Output Parameters:
    9617: + ornt  - The orientation (transformation) which will take the source arrangement to the target arrangement
    9618: - found - Flag indicating that a suitable orientation was found

    9620:   Level: advanced

    9622:   Note:
    9623:   An arrangement is a face order combined with an orientation for each face

    9625:   Each orientation (transformation) is labeled with an integer from negative `DMPolytopeTypeGetNumArrangements(ct)`/2 to `DMPolytopeTypeGetNumArrangements(ct)`/2
    9626:   that labels each arrangement (face ordering plus orientation for each face).

    9628:   See `DMPolytopeMatchVertexOrientation()` to find a new vertex orientation that takes the source vertex arrangement to the target vertex arrangement

    9630: .seealso: [](ch_dmbase), `DM`, `DMPolytopeGetOrientation()`, `DMPolytopeMatchVertexOrientation()`, `DMPolytopeGetVertexOrientation()`
    9631: @*/
    9632: PetscErrorCode DMPolytopeMatchOrientation(DMPolytopeType ct, const PetscInt sourceCone[], const PetscInt targetCone[], PetscInt *ornt, PetscBool *found)
    9633: {
    9634:   const PetscInt cS = DMPolytopeTypeGetConeSize(ct);
    9635:   const PetscInt nO = DMPolytopeTypeGetNumArrangements(ct) / 2;
    9636:   PetscInt       o, c;

    9638:   PetscFunctionBegin;
    9639:   if (!nO) {
    9640:     *ornt  = 0;
    9641:     *found = PETSC_TRUE;
    9642:     PetscFunctionReturn(PETSC_SUCCESS);
    9643:   }
    9644:   for (o = -nO; o < nO; ++o) {
    9645:     const PetscInt *arr = DMPolytopeTypeGetArrangement(ct, o);

    9647:     for (c = 0; c < cS; ++c)
    9648:       if (sourceCone[arr[c * 2]] != targetCone[c]) break;
    9649:     if (c == cS) {
    9650:       *ornt = o;
    9651:       break;
    9652:     }
    9653:   }
    9654:   *found = o == nO ? PETSC_FALSE : PETSC_TRUE;
    9655:   PetscFunctionReturn(PETSC_SUCCESS);
    9656: }

    9658: /*@
    9659:   DMPolytopeGetOrientation - Determine an orientation (transformation) that takes the source face arrangement to the target face arrangement

    9661:   Not Collective

    9663:   Input Parameters:
    9664: + ct         - The `DMPolytopeType`
    9665: . sourceCone - The source arrangement of faces
    9666: - targetCone - The target arrangement of faces

    9668:   Output Parameter:
    9669: . ornt - The orientation (transformation) which will take the source arrangement to the target arrangement

    9671:   Level: advanced

    9673:   Note:
    9674:   This function is the same as `DMPolytopeMatchOrientation()` except it will generate an error if no suitable orientation can be found.

    9676:   Developer Note:
    9677:   It is unclear why this function needs to exist since one can simply call `DMPolytopeMatchOrientation()` and error if none is found

    9679: .seealso: [](ch_dmbase), `DM`, `DMPolytopeType`, `DMPolytopeMatchOrientation()`, `DMPolytopeGetVertexOrientation()`, `DMPolytopeMatchVertexOrientation()`
    9680: @*/
    9681: PetscErrorCode DMPolytopeGetOrientation(DMPolytopeType ct, const PetscInt sourceCone[], const PetscInt targetCone[], PetscInt *ornt)
    9682: {
    9683:   PetscBool found;

    9685:   PetscFunctionBegin;
    9686:   PetscCall(DMPolytopeMatchOrientation(ct, sourceCone, targetCone, ornt, &found));
    9687:   PetscCheck(found, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Could not find orientation for %s", DMPolytopeTypes[ct]);
    9688:   PetscFunctionReturn(PETSC_SUCCESS);
    9689: }

    9691: /*@
    9692:   DMPolytopeMatchVertexOrientation - Determine an orientation (transformation) that takes the source vertex arrangement to the target vertex arrangement

    9694:   Not Collective

    9696:   Input Parameters:
    9697: + ct         - The `DMPolytopeType`
    9698: . sourceVert - The source arrangement of vertices
    9699: - targetVert - The target arrangement of vertices

    9701:   Output Parameters:
    9702: + ornt  - The orientation (transformation) which will take the source arrangement to the target arrangement
    9703: - found - Flag indicating that a suitable orientation was found

    9705:   Level: advanced

    9707:   Notes:
    9708:   An arrangement is a vertex order

    9710:   Each orientation (transformation) is labeled with an integer from negative `DMPolytopeTypeGetNumArrangements(ct)`/2 to `DMPolytopeTypeGetNumArrangements(ct)`/2
    9711:   that labels each arrangement (vertex ordering).

    9713:   See `DMPolytopeMatchOrientation()` to find a new face orientation that takes the source face arrangement to the target face arrangement

    9715: .seealso: [](ch_dmbase), `DM`, `DMPolytopeType`, `DMPolytopeGetOrientation()`, `DMPolytopeMatchOrientation()`, `DMPolytopeTypeGetNumVertices()`, `DMPolytopeTypeGetVertexArrangement()`
    9716: @*/
    9717: PetscErrorCode DMPolytopeMatchVertexOrientation(DMPolytopeType ct, const PetscInt sourceVert[], const PetscInt targetVert[], PetscInt *ornt, PetscBool *found)
    9718: {
    9719:   const PetscInt cS = DMPolytopeTypeGetNumVertices(ct);
    9720:   const PetscInt nO = DMPolytopeTypeGetNumArrangements(ct) / 2;
    9721:   PetscInt       o, c;

    9723:   PetscFunctionBegin;
    9724:   if (!nO) {
    9725:     *ornt  = 0;
    9726:     *found = PETSC_TRUE;
    9727:     PetscFunctionReturn(PETSC_SUCCESS);
    9728:   }
    9729:   for (o = -nO; o < nO; ++o) {
    9730:     const PetscInt *arr = DMPolytopeTypeGetVertexArrangement(ct, o);

    9732:     for (c = 0; c < cS; ++c)
    9733:       if (sourceVert[arr[c]] != targetVert[c]) break;
    9734:     if (c == cS) {
    9735:       *ornt = o;
    9736:       break;
    9737:     }
    9738:   }
    9739:   *found = o == nO ? PETSC_FALSE : PETSC_TRUE;
    9740:   PetscFunctionReturn(PETSC_SUCCESS);
    9741: }

    9743: /*@
    9744:   DMPolytopeGetVertexOrientation - Determine an orientation (transformation) that takes the source vertex arrangement to the target vertex arrangement

    9746:   Not Collective

    9748:   Input Parameters:
    9749: + ct         - The `DMPolytopeType`
    9750: . sourceCone - The source arrangement of vertices
    9751: - targetCone - The target arrangement of vertices

    9753:   Output Parameter:
    9754: . ornt - The orientation (transformation) which will take the source arrangement to the target arrangement

    9756:   Level: advanced

    9758:   Note:
    9759:   This function is the same as `DMPolytopeMatchVertexOrientation()` except it errors if not orientation is possible.

    9761:   Developer Note:
    9762:   It is unclear why this function needs to exist since one can simply call `DMPolytopeMatchVertexOrientation()` and error if none is found

    9764: .seealso: [](ch_dmbase), `DM`, `DMPolytopeType`, `DMPolytopeMatchVertexOrientation()`, `DMPolytopeGetOrientation()`
    9765: @*/
    9766: PetscErrorCode DMPolytopeGetVertexOrientation(DMPolytopeType ct, const PetscInt sourceCone[], const PetscInt targetCone[], PetscInt *ornt)
    9767: {
    9768:   PetscBool found;

    9770:   PetscFunctionBegin;
    9771:   PetscCall(DMPolytopeMatchVertexOrientation(ct, sourceCone, targetCone, ornt, &found));
    9772:   PetscCheck(found, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Could not find orientation for %s", DMPolytopeTypes[ct]);
    9773:   PetscFunctionReturn(PETSC_SUCCESS);
    9774: }

    9776: /*@
    9777:   DMPolytopeInCellTest - Check whether a point lies inside the reference cell of given type

    9779:   Not Collective

    9781:   Input Parameters:
    9782: + ct    - The `DMPolytopeType`
    9783: - point - Coordinates of the point

    9785:   Output Parameter:
    9786: . inside - Flag indicating whether the point is inside the reference cell of given type

    9788:   Level: advanced

    9790: .seealso: [](ch_dmbase), `DM`, `DMPolytopeType`, `DMLocatePoints()`
    9791: @*/
    9792: PetscErrorCode DMPolytopeInCellTest(DMPolytopeType ct, const PetscReal point[], PetscBool *inside)
    9793: {
    9794:   PetscReal sum = 0.0;
    9795:   PetscInt  d;

    9797:   PetscFunctionBegin;
    9798:   *inside = PETSC_TRUE;
    9799:   switch (ct) {
    9800:   case DM_POLYTOPE_TRIANGLE:
    9801:   case DM_POLYTOPE_TETRAHEDRON:
    9802:     for (d = 0; d < DMPolytopeTypeGetDim(ct); ++d) {
    9803:       if (point[d] < -1.0) {
    9804:         *inside = PETSC_FALSE;
    9805:         break;
    9806:       }
    9807:       sum += point[d];
    9808:     }
    9809:     if (sum > PETSC_SMALL) {
    9810:       *inside = PETSC_FALSE;
    9811:       break;
    9812:     }
    9813:     break;
    9814:   case DM_POLYTOPE_QUADRILATERAL:
    9815:   case DM_POLYTOPE_HEXAHEDRON:
    9816:     for (d = 0; d < DMPolytopeTypeGetDim(ct); ++d)
    9817:       if (PetscAbsReal(point[d]) > 1. + PETSC_SMALL) {
    9818:         *inside = PETSC_FALSE;
    9819:         break;
    9820:       }
    9821:     break;
    9822:   default:
    9823:     SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Unsupported polytope type %s", DMPolytopeTypes[ct]);
    9824:   }
    9825:   PetscFunctionReturn(PETSC_SUCCESS);
    9826: }

    9828: /*@
    9829:   DMReorderSectionSetDefault - Set flag indicating whether the local section should be reordered by default

    9831:   Logically collective

    9833:   Input Parameters:
    9834: + dm      - The DM
    9835: - reorder - Flag for reordering

    9837:   Level: intermediate

    9839: .seealso: `DMReorderSectionGetDefault()`
    9840: @*/
    9841: PetscErrorCode DMReorderSectionSetDefault(DM dm, DMReorderDefaultFlag reorder)
    9842: {
    9843:   PetscFunctionBegin;
    9845:   PetscTryMethod(dm, "DMReorderSectionSetDefault_C", (DM, DMReorderDefaultFlag), (dm, reorder));
    9846:   PetscFunctionReturn(PETSC_SUCCESS);
    9847: }

    9849: /*@
    9850:   DMReorderSectionGetDefault - Get flag indicating whether the local section should be reordered by default

    9852:   Not collective

    9854:   Input Parameter:
    9855: . dm - The DM

    9857:   Output Parameter:
    9858: . reorder - Flag for reordering

    9860:   Level: intermediate

    9862: .seealso: `DMReorderSetDefault()`
    9863: @*/
    9864: PetscErrorCode DMReorderSectionGetDefault(DM dm, DMReorderDefaultFlag *reorder)
    9865: {
    9866:   PetscFunctionBegin;
    9868:   PetscAssertPointer(reorder, 2);
    9869:   *reorder = DM_REORDER_DEFAULT_NOTSET;
    9870:   PetscTryMethod(dm, "DMReorderSectionGetDefault_C", (DM, DMReorderDefaultFlag *), (dm, reorder));
    9871:   PetscFunctionReturn(PETSC_SUCCESS);
    9872: }

    9874: /*@
    9875:   DMReorderSectionSetType - Set the type of local section reordering

    9877:   Logically collective

    9879:   Input Parameters:
    9880: + dm      - The DM
    9881: - reorder - The reordering method

    9883:   Level: intermediate

    9885: .seealso: `DMReorderSectionGetType()`, `DMReorderSectionSetDefault()`
    9886: @*/
    9887: PetscErrorCode DMReorderSectionSetType(DM dm, MatOrderingType reorder)
    9888: {
    9889:   PetscFunctionBegin;
    9891:   PetscTryMethod(dm, "DMReorderSectionSetType_C", (DM, MatOrderingType), (dm, reorder));
    9892:   PetscFunctionReturn(PETSC_SUCCESS);
    9893: }

    9895: /*@
    9896:   DMReorderSectionGetType - Get the reordering type for the local section

    9898:   Not collective

    9900:   Input Parameter:
    9901: . dm - The DM

    9903:   Output Parameter:
    9904: . reorder - The reordering method

    9906:   Level: intermediate

    9908: .seealso: `DMReorderSetDefault()`, `DMReorderSectionGetDefault()`
    9909: @*/
    9910: PetscErrorCode DMReorderSectionGetType(DM dm, MatOrderingType *reorder)
    9911: {
    9912:   PetscFunctionBegin;
    9914:   PetscAssertPointer(reorder, 2);
    9915:   *reorder = NULL;
    9916:   PetscTryMethod(dm, "DMReorderSectionGetType_C", (DM, MatOrderingType *), (dm, reorder));
    9917:   PetscFunctionReturn(PETSC_SUCCESS);
    9918: }