MatMPIAIJSetPreallocationCSR#
Allocates memory for a sparse parallel matrix in MATAIJ
format (the default parallel PETSc format).
Synopsis#
#include "petscmat.h"
PetscErrorCode MatMPIAIJSetPreallocationCSR(Mat B, const PetscInt i[], const PetscInt j[], const PetscScalar v[])
Collective
Input Parameters#
B - the matrix
i - the indices into j for the start of each local row (starts with zero)
j - the column indices for each local row (starts with zero)
v - optional values in the matrix
Notes#
The i
, j
, and v
arrays ARE copied by this routine into the internal format used by PETSc;
thus you CANNOT change the matrix entries by changing the values of v
after you have
called this routine. Use MatCreateMPIAIJWithSplitArrays()
to avoid needing to copy the arrays.
The i
and j
indices are 0 based, and i
indices are indices corresponding to the local j
array.
The format which is used for the sparse matrix input, is equivalent to a row-major ordering.. i.e for the following matrix, the input data expected is as shown
1 0 0
2 0 3 P0
-------
4 5 6 P1
Process0 [P0] rows_owned=[0,1]
i = {0,1,3} [size = nrow+1 = 2+1]
j = {0,0,2} [size = 3]
v = {1,2,3} [size = 3]
Process1 [P1] rows_owned=[2]
i = {0,3} [size = nrow+1 = 1+1]
j = {0,1,2} [size = 3]
v = {4,5,6} [size = 3]
See Also#
Matrices, Mat
, MATMPIAIJ
, MatCreate()
, MatCreateSeqAIJ()
, MatSetValues()
, MatMPIAIJSetPreallocation()
, MatCreateAIJ()
, MATMPIAIJ
,
MatCreateSeqAIJWithArrays()
, MatCreateMPIAIJWithSplitArrays()
Level#
developer
Location#
Implementations#
MatMPIAIJSetPreallocationCSR_MPIAIJ in src/mat/impls/aij/mpi/mpiaij.c
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