#include "petscmat.h" PetscErrorCode MatPtAP(Mat A,Mat P,MatReuse scall,PetscReal fill,Mat *C)Neighbor-wise Collective on Mat
| A | - the matrix | |
| P | - the projection matrix | |
| scall | - either MAT_INITIAL_MATRIX or MAT_REUSE_MATRIX | |
| fill | - expected fill as ratio of nnz(C)/(nnz(A) + nnz(P)), use PETSC_DEFAULT if you do not have a good estimate if the result is a dense matrix this is irrelevent |
This routine is currently only implemented for pairs of sequential dense matrices, AIJ matrices and classes which inherit from AIJ.