petsc-3.7.1 2016-05-15
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MatMatMatMult

Performs Matrix-Matrix-Matrix Multiplication D=A*B*C.

Synopsis

#include "petscmat.h" 
PetscErrorCode MatMatMatMult(Mat A,Mat B,Mat C,MatReuse scall,PetscReal fill,Mat *D)
Neighbor-wise Collective on Mat Many br

Input Parameters

A - the left matrix Many br
B - the middle matrix Many br
C - the right matrix Many br
scall - either MAT_INITIAL_MATRIX or MAT_REUSE_MATRIX Many br
fill - expected fill as ratio of nnz(D)/(nnz(A) + nnz(B)+nnz(C)), use PETSC_DEFAULT if you do not have a good estimate Many brif the result is a dense matrix this is irrelevent Many br

Output Parameters

D -the product matrix Many br

Notes

Unless scall is MAT_REUSE_MATRIX D will be created. Many br

MAT_REUSE_MATRIX can only be used if the matrices A, B and C have the same nonzero pattern as in the previous call Many br

To determine the correct fill value, run with -info and search for the string "Fill ratio" to see the value Many bractually needed. Many br

If you have many matrices with the same non-zero structure to multiply, you Many brshould use MAT_REUSE_MATRIX in all calls but the first or Many br

Many br

See Also

MatMatMult, MatPtAP()

Level:intermediate
Location:
src/mat/interface/matrix.c
Index of all Mat routines
Table of Contents for all manual pages
Index of all manual pages