petsc-3.14.6 2021-03-30
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MatMPIAIJGetLocalMat

 Creates a SeqAIJ from a MATMPIAIJ matrix by taking all its local rows and putting them into a sequential matrix with mlocal rows and n columns. Where mlocal is the row count obtained with MatGetLocalSize() and n is the global column count obtained with MatGetSize()

Synopsis

#include "petscmat.h" 
PetscErrorCode MatMPIAIJGetLocalMat(Mat A,MatReuse scall,Mat *A_loc)
Not Collective

Input Parameters

A - the matrix
scall - either MAT_INITIAL_MATRIX or MAT_REUSE_MATRIX

Output Parameter

A_loc - the local sequential matrix generated

Notes

When the communicator associated with A has size 1 and MAT_INITIAL_MATRIX is requested, the matrix returned is the diagonal part of A. If MAT_REUSE_MATRIX is requested with comm size 1, MatCopy(Adiag,*A_loc,SAME_NONZERO_PATTERN) is called. This means that one can preallocate the proper sequential matrix first and then call this routine with MAT_REUSE_MATRIX to safely modify the values of the returned A_loc.

See Also

MatGetOwnershipRange(), MatMPIAIJGetLocalMatCondensed()

Level

developer

Location

src/mat/impls/aij/mpi/mpiaij.c
Index of all Mat routines
Table of Contents for all manual pages
Index of all manual pages