MatProductCreate#

create a matrix to hold the result of a matrix-matrix product operation

Synopsis#

#include "petscmat.h" 
PetscErrorCode MatProductCreate(Mat A, Mat B, Mat C, Mat *D)

Collective

Input Parameters#

A - the first matrix
B - the second matrix
C - the third matrix (or NULL)

Output Parameter#

D - the matrix whose values are to be computed via a matrix-matrix product operation

Example#

    MatProductCreate(A,B,C,&D); or MatProductCreateWithMat(A,B,C,D)
    MatProductSetType(D, MATPRODUCT_AB or MATPRODUCT_AtB or MATPRODUCT_ABt or MATPRODUCT_PtAP or MATPRODUCT_RARt or MATPRODUCT_ABC)
    MatProductSetAlgorithm(D, alg)
    MatProductSetFill(D,fill)
    MatProductSetFromOptions(D)
    MatProductSymbolic(D)
    MatProductNumeric(D)
    Change numerical values in some of the matrices
    MatProductNumeric(D)

Notes#

Use MatProductCreateWithMat() if the matrix you wish computed, the D matrix, already exists.

The information computed during the symbolic stage can be reused for new numerical computations with the same non-zero structure

Developer Note#

It is undocumented what happens if the nonzero structure of the input matrices changes. Is the symbolic stage automatically redone? Does it crash? Is there error checking for it?