# MatMFFDSetBase#

Sets the vector U at which matrix vector products of the Jacobian are computed for the MATMFFD matrix

## Synopsis#

#include "petscmat.h"
PetscErrorCode MatMFFDSetBase(Mat J, Vec U, Vec F)


Logically Collective

## Input Parameters#

• J - the MATMFFD matrix

• U - the vector

• F - (optional) vector that contains F(u) if it has been already computed

## Notes#

This is rarely used directly

If F is provided then it is not recomputed. Otherwise the function is evaluated at the base point during the first MatMult() after each call to MatMFFDSetBase().

MATMFFD, MatMult(), MatMFFDSetBase()