DMPlexVecGetOrientedClosure — PETSc 3.25.4 documentation

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# DMPlexVecGetOrientedClosure

Get an array of the values on the closure of `point` with a given orientation, optionally applying the closure permutation.

## Synopsis

    #include "petscdmplex.h"
    PetscErrorCode DMPlexVecGetOrientedClosure(DM dm, PetscSection section, PetscBool useClPerm, Vec v, PetscInt point, PetscInt ornt, PetscInt *csize, PetscScalar *values[])

Not collective

## Input Parameters

- dm - The `DM`

- section - The section describing the layout in `v`, or `NULL` to use the default section

- useClPerm - Flag for whether the provided closure permutation should be applied to the values

- v - The local vector

- point - The point in the `DM`

- ornt - The orientation of the cell, an integer giving the prescription for cone traversal. Typically, this will be 0.

## Input/Output Parameters

- csize - The size of the input values array, or `NULL`; on output the number of values in the closure

- values - An array to use for the values, or *values = `NULL` to have it allocated automatically; if the user provided `NULL`, it is a borrowed array and should not be freed, use `DMPlexVecRestoreClosure()` to return it

## Notes

`DMPlexVecGetOrientedClosure()`/`DMPlexVecRestoreClosure()` only allocates the values array if it set to `NULL` in the calling function. This is because `DMPlexVecGetOrientedClosure()` is typically called in the inner loop of a `Vec` or `Mat` assembly function, and a user may already have allocated storage for this operation.

## Fortran Notes

The `csize` argument is present in the Fortran binding. Since the Fortran `values` array contains its length information this argument may not be needed. In that case one may pass `PETSC_NULL_INTEGER` for `csize`.

`values` must be declared with

      PetscScalar,dimension(:),pointer   :: values

and it will be allocated internally by PETSc to hold the values returned

## See Also

DMPlex: Unstructured Grids, `DM`, `DMPLEX`, `DMPlexVecGetClosure()`, `DMPlexGetCellCoordinates()`, `DMPlexVecRestoreClosure()`, `DMPlexVecSetClosure()`

## Level

advanced

## Location

src/dm/impls/plex/plex.c

Index of all DMPlex routines
Table of Contents for all manual pages
Index of all manual pages