petsc-3.14.6 2021-03-30
MatMPIAIJSetPreallocationCSR
Allocates memory for a sparse parallel matrix in AIJ 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
MatCreate(), MatCreateSeqAIJ(), MatSetValues(), MatMPIAIJSetPreallocation(), MatCreateAIJ(), MATMPIAIJ,
MatCreateSeqAIJWithArrays(), MatCreateMPIAIJWithSplitArrays()
Level
developer
Location
src/mat/impls/aij/mpi/mpiaij.c
Implementations
MatMPIAIJSetPreallocationCSR_MPIAIJ in src/mat/impls/aij/mpi/mpiaij.c
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