petsc-3.8.4 2018-03-24

MatFDColoringSetParameters

Sets the parameters for the sparse approximation of a Jacobian matrix using finite differences.

Synopsis

#include "petscmat.h" 
PetscErrorCode MatFDColoringSetParameters(MatFDColoring matfd,PetscReal error,PetscReal umin)

Logically Collective on MatFDColoring

The Jacobian is estimated with the differencing approximation

       F'(u)_{:,i} = [F(u+h*dx_{i}) - F(u)]/h where
       h = error_rel*u[i]                 if  abs(u[i]) > umin
         = +/- error_rel*umin             otherwise, with +/- determined by the sign of u[i]
       dx_{i} = (0, ... 1, .... 0)

Input Parameters

	coloring	- the coloring context
	error_rel	- relative error
	umin	- minimum allowable u-value magnitude

Keywords

Mat, finite differences, coloring, set, parameters

MatFDColoringSetParameters

Synopsis

Input Parameters

Keywords

See Also