petsc-3.5.0 2014-06-30
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MatFDColoringSetFromOptions

Sets coloring finite difference parameters from the options database.

Synopsis

#include "petscmat.h" 
PetscErrorCode  MatFDColoringSetFromOptions(MatFDColoring matfd)
Collective on MatFDColoring

The Jacobian, F'(u), 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 Parameter

coloring -the coloring context

Options Database Keys

-mat_fd_coloring_err <err> - Sets <err> (square root of relative error in the function)
-mat_fd_coloring_umin <umin> - Sets umin, the minimum allowable u-value magnitude
-mat_fd_type - "wp" or "ds" (see MATMFFD_WP or MATMFFD_DS)
-mat_fd_coloring_view - Activates basic viewing
-mat_fd_coloring_view ::ascii_info - Activates viewing info
-mat_fd_coloring_view draw - Activates drawing

Keywords

Mat, finite differences, parameters

See Also

MatFDColoringCreate(), MatFDColoringView(), MatFDColoringSetParameters()

Level:intermediate
Location:
src/mat/matfd/fdmatrix.c
Index of all MatFD routines
Table of Contents for all manual pages
Index of all manual pages

Examples

src/mat/examples/tutorials/ex16.c.html
src/snes/examples/tutorials/ex5s.c.html
src/snes/examples/tutorials/ex14.c.html
src/tao/unconstrained/examples/tutorials/minsurf2.c.html