MatMPIAIJGetLocalMat#
Creates a MATSEQAIJ 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_MATRIXorMAT_REUSE_MATRIX
Output Parameter#
A_loc - the local sequential matrix generated
Notes#
In other words combines the two parts of a parallel MATMPIAIJ matrix on each process to a single matrix.
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#
Matrices, Mat, MATMPIAIJ, MatGetOwnershipRange(), MatMPIAIJGetLocalMatCondensed(), MatMPIAIJGetLocalMatMerge()
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