Date: 2026-06-01T23:13:17+00:00

Actual source code: pcisimpl.h

      1: #pragma once

      3: #include <petsc/private/pcimpl.h>
      4: #include <petsc/private/matisimpl.h>
      5: #include <petscksp.h>

      7: /*
      8:    Context (data structure) common for all Iterative Substructuring preconditioners.
      9: */

     11: typedef struct {
     12:   /*
     13:      In naming the variables, we adopted the following convention:
     14:      * B - stands for interface nodes;
     15:      * I - stands for interior nodes;
     16:      * D - stands for Dirichlet (by extension, refers to interior
     17:            nodes) and
     18:      * N - stands for Neumann (by extension, refers to all local
     19:            nodes, interior plus interface).
     20:      In some cases, I or D would apply equally well (e.g. vec1_D).
     21:   */

     23:   PetscInt n;          /* number of nodes (interior+interface) in this subdomain */
     24:   PetscInt n_B;        /* number of interface nodes in this subdomain */
     25:   IS       is_B_local, /* local (sequential) index sets for interface (B) and interior (I) nodes */
     26:     is_I_local, is_B_global, is_I_global;

     28:   Mat A_II, A_IB, /* local (sequential) submatrices */
     29:     A_BI, A_BB;
     30:   Mat pA_II;
     31:   Vec D;     /* diagonal scaling "matrix" (stored as a vector, since it's diagonal) */
     32:   KSP ksp_N, /* linear solver contexts */
     33:     ksp_D;
     34:   Vec vec1_N, /* local (sequential) work vectors */
     35:     vec2_N, vec1_D, vec2_D, vec3_D, vec4_D, vec1_B, vec2_B, vec3_B, vec1_global;

     37:   PetscScalar *work_N;
     38:   VecScatter   N_to_D;      /* scattering context from all local nodes to local interior nodes */
     39:   VecScatter   global_to_D; /* scattering context from global to local interior nodes */
     40:   VecScatter   N_to_B;      /* scattering context from all local nodes to local interface nodes */
     41:   VecScatter   global_to_B; /* scattering context from global to local interface nodes */
     42:   PetscBool    pure_neumann;
     43:   PetscScalar  scaling_factor;
     44:   PetscBool    use_stiffness_scaling;

     46:   ISLocalToGlobalMapping mapping;
     47:   PetscInt               n_neigh;  /* should use PetscMPIInt number of neighbours this subdomain/MPI process has (INCLUDING the subdomain itself). */
     48:   PetscInt              *neigh;    /* list of neighbouring subdomains, MPI processes  */
     49:   PetscInt              *n_shared; /* n_shared[j] is the number of nodes shared with subdomain neigh[j] */
     50:   PetscInt             **shared;   /* shared[j][i] is the local index of the i-th node shared with subdomain neigh[j] */
     51:   /*
     52:      It is necessary some consistency in the
     53:      numbering of the shared edges from each side.
     54:      For instance:

     56:      +-------+-------+
     57:      |   k   |   l   | subdomains k and l are neighbours
     58:      +-------+-------+

     60:      Let i and j be s.t. proc[k].neigh[i]==l and
     61:                          proc[l].neigh[j]==k.

     63:      We need:
     64:      proc[k].loc_to_glob(proc[k].shared[i][m]) == proc[l].loc_to_glob(proc[l].shared[j][m])
     65:      for all 0 <= m < proc[k].n_shared[i], or equiv'ly, for all 0 <= m < proc[l].n_shared[j]
     66:   */
     67:   ISLocalToGlobalMapping BtoNmap;
     68:   PetscBool              reusesubmatrices;
     69: } PC_IS;