MatCreateSeqAIJWithArrays#

Creates an sequential MATSEQAIJ matrix using matrix elements (in CSR format) provided by the user.

Synopsis#

#include "petscmat.h" 
PetscErrorCode MatCreateSeqAIJWithArrays(MPI_Comm comm, PetscInt m, PetscInt n, PetscInt i[], PetscInt j[], PetscScalar a[], Mat *mat)

Collective

Input Parameters#

comm - must be an MPI communicator of size 1
m - number of rows
n - number of columns
i - row indices; that is i[0] = 0, i[row] = i[row-1] + number of elements in that row of the matrix
j - column indices
a - matrix values

Output Parameter#

mat - the matrix

Notes#

The i, j, and a arrays are not copied by this routine, the user must free these arrays once the matrix is destroyed and not before

You cannot set new nonzero locations into this matrix, that will generate an error.

The i and j indices are 0 based

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
        4 5 6

        i =  {0,1,3,6}  [size = nrow+1  = 3+1]
        j =  {0,0,2,0,1,2}  [size = 6]; values must be sorted for each row
        v =  {1,2,3,4,5,6}  [size = 6]