petsc-3.14.6 2021-03-30

MatMFFDSetCheckh

Sets a function that checks the computed h and adjusts it to satisfy some criteria

#include "petscmat.h"   
PetscErrorCode  MatMFFDSetCheckh(Mat J,PetscErrorCode (*fun)(void*,Vec,Vec,PetscScalar*),void *ctx)

Logically Collective on Mat

	J	- the MatMFFD matrix
	fun	- the function that checks h
	ctx	- any context needed by the function

-mat_mffd_check_positivity

For example, MatMFFDCheckPositivity() insures that all entries of U + h*a are non-negative

The function you provide is called after the default h has been computed and allows you to modify it.

advanced