MatMatMatMult#
Performs matrix-matrix-matrix multiplication D=ABC.
Synopsis#
#include "petscmat.h" 
PetscErrorCode MatMatMatMult(Mat A, Mat B, Mat C, MatReuse scall, PetscReal fill, Mat *D)
Neighbor-wise Collective
Input Parameters#
- A - the left matrix 
- B - the middle matrix 
- C - the right matrix 
- scall - either - MAT_INITIAL_MATRIXor- MAT_REUSE_MATRIX
- fill - expected fill as ratio of nnz(D)/(nnz(A) + nnz(B)+nnz(C)), use - PETSC_DETERMINEor- PETSC_CURRENTif you do not have a good estimate if the result is a dense matrix this is irrelevant
Output Parameter#
- D - the product matrix 
Notes#
Unless scall is MAT_REUSE_MATRIX D will be created.
MAT_REUSE_MATRIX can only be used if the matrices A, B, and C have the same nonzero pattern as in the previous call
This routine is shorthand for using MatProductCreate() with the MatProductType of MATPRODUCT_ABC
To determine the correct fill value, run with -info and search for the string “Fill ratio” to see the value
actually needed.
If you have many matrices with the same non-zero structure to multiply, you
should use MAT_REUSE_MATRIX in all calls but the first
The deprecated PETSC_DEFAULT in fill also means use the current value
See Also#
Matrices, Mat, MatProductCreate(), MATPRODUCT_ABC, MatMatMult, MatPtAP(), MatMatTransposeMult(), MatTransposeMatMult()
Level#
intermediate
Location#
Examples#
Index of all Mat routines
Table of Contents for all manual pages
Index of all manual pages