#include "petscmat.h" PetscErrorCode MatMatMultSymbolic(Mat A,Mat B,PetscReal fill,Mat *C)Neighbor-wise Collective on Mat
|A||- the left matrix|
|B||- the right matrix|
|fill||- expected fill as ratio of nnz(C)/(nnz(A) + nnz(B)), use PETSC_DEFAULT if you do not have a good estimate, if C is a dense matrix this is irrelevent|
To determine the correct fill value, run with -info and search for the string "Fill ratio" to see the value actually needed.
This routine is currently implemented for - pairs of AIJ matrices and classes which inherit from AIJ, C will be of type AIJ - pairs of AIJ (A) and Dense (B) matrix, C will be of type Dense. - pairs of Dense (A) and AIJ (B) matrix, C will be of type Dense.
Developers Note: There are ways to estimate the number of nonzeros in the resulting product, see for example, http://arxiv.org/abs/1006.4173 We should incorporate them into PETSc.
Index of all Mat routines
Table of Contents for all manual pages
Index of all manual pages