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
Input Parameters#
matfd - the coloring context
error - relative error
umin - minimum allowable u-value magnitude
Note#
The Jacobian is estimated with the differencing approximation
F'(u)_{:,i} = [F(u+h*dx_{i}) - F(u)]/h where
htype = 'ds':
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)
htype = 'wp':
h = error_rel * sqrt(1 + ||u||)
See Also#
Mat, MatFDColoring, MatFDColoringCreate(), MatFDColoringSetFromOptions()
Level#
advanced
Location#
Index of all MatFD routines
Table of Contents for all manual pages
Index of all manual pages