MatMatMult

Performs Matrix-Matrix Multiplication C=A*B.

#include "petscmat.h" 
PetscErrorCode PETSCMAT_DLLEXPORT MatMatMult(Mat A,Mat B,MatReuse scall,PetscReal fill,Mat *C)

Collective on Mat

	A	- the left matrix
	B	- the right matrix
	scall	- either MAT_INITIAL_MATRIX or MAT_REUSE_MATRIX
	fill	- expected fill as ratio of nnz(C)/(nnz(A) + nnz(B))

C -the product matrix

C will be created and must be destroyed by the user with MatDestroy(). Unless scall is MAT_REUSE_MATRIX

If you have many matrices with the same non-zero structure to multiply, you should either

  1) use MAT_REUSE_MATRIX in all calls but the first or

  2) call MatMatMultSymbolic() once and then MatMatMultNumeric() for each product needed