petsc-3.7.5 2017-01-01

MatCreateMPIAIJWithArrays

creates a MPI AIJ matrix using arrays that contain in standard CSR format the local rows.

Synopsis

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

Collective on MPI_Comm

Input Parameters

	comm	- MPI communicator
	m	- number of local rows (Cannot be PETSC_DECIDE)
	n	- This value should be the same as the local size used in creating the x vector for the matrix-vector product y = Ax. (or PETSC_DECIDE to have calculated if N is given) For square matrices n is almost always m.
	M	- number of global rows (or PETSC_DETERMINE to have calculated if m is given)
	N	- number of global columns (or PETSC_DETERMINE to have calculated if n is given)
	i	- row indices
	j	- column indices
	a	- matrix values

Output Parameter

mat -the matrix

Notes

The i, j, and a 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 a[] 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]

Keywords