DMDACreatePatchIS

Creates an index set corresponding to a logically rectangular patch of the DMDA.

Synopsis

#include "petscdmda.h"   
PetscErrorCode DMDACreatePatchIS(DM da, MatStencil *lower, MatStencil *upper, IS *is, PetscBool offproc)

Collective

Input Parameters

• da - the DMDA

• lower - a MatStencil with i, j and k entries corresponding to the lower corner of the patch

• upper - a MatStencil with i, j and k entries corresponding to the upper corner of the patch

• offproc - indicate whether the returned IS will contain off process indices

Output Parameter

• is - the IS corresponding to the patch

Notes

This routine always returns an IS on the DMDA communicator.

If offproc is set to PETSC_TRUE, the routine returns an IS with all the indices requested regardless of whether these indices are present on the requesting MPI process or not. Thus, it is upon the caller to ensure that the indices returned in this mode are appropriate.

If offproc is set to PETSC_FALSE, the IS only returns the subset of indices that are present on the requesting MPI process and there is no duplication of indices between multiple MPI processes.

See Also

DMDA - Creating vectors for structured grids, DM, DMDA, DMCreateDomainDecomposition(), DMCreateDomainDecompositionScatters()

Level

developer

Location

src/dm/impls/da/dadd.c

Examples

src/dm/tutorials/ex14.c
src/dm/tutorials/ex22.c

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Index of all DMDA routines
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