MatFDColoringSetFromOptions

Sets coloring finite difference parameters from the options database.

Synopsis

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

Collective

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

• matfd - the coloring context

Options Database Keys

• -mat_fd_coloring_err - Sets (square root of relative error in the function)

• -mat_fd_coloring_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

See Also

Mat, MatFDColoring, MatFDColoringCreate(), MatFDColoringView(), MatFDColoringSetParameters()

Level

intermediate

Location

src/mat/matfd/fdmatrix.c

Examples

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

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Index of all MatFD routines
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Index of all manual pages