#include "petscmat.h" PetscErrorCode MatMPIAIJSetPreallocationCSR(Mat B,const PetscInt i[],const PetscInt j[], const PetscScalar v[])Collective on MPI_Comm
| 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 |
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]