petsc-3.5.4 2015-05-23

MatMFFDSetFunction

Sets the function used in applying the matrix free.

#include "petscmat.h"   
PetscErrorCode  MatMFFDSetFunction(Mat mat,PetscErrorCode (*func)(void*,Vec,Vec),void *funcctx)

Logically Collective on Mat

	mat	- the matrix free matrix created via MatCreateSNESMF() or MatCreateMFFD()
	func	- the function to use
	funcctx	- optional function context passed to function

    func (void *funcctx, Vec x, Vec f)

If you use this you MUST call MatAssemblyBegin()/MatAssemblyEnd() on the matrix free matrix inside your compute Jacobian routine

If this is not set then it will use the function set with SNESSetFunction() if MatCreateSNESMF() was used.

SNES, matrix-free, function