tao2.1p0 20120724
TaoDefaultComputeGradient
computes the gradient using finite differences.
Synopsis
#include "taosolver.h"
PetscErrorCode TaoDefaultComputeGradient(TaoSolver tao,Vec X,Vec G,void *dummy)
Collective on TaoSolver
Input Parameters
 tao   the TaoSolver context

 X   compute gradient at this point

 dummy   not used

Output Parameters
G Gradient Vector
Options Database Key
 tao_fd_gradient   Activates TaoDefaultComputeGradient()

 tao_fd_delta <delta>   change in x used to calculate finite differences

Note
This routine is slow and expensive, and is not currently optimized
to take advantage of sparsity in the problem. Although
TaoAppDefaultComputeGradient is not recommended for general use
in largescale applications, It can be useful in checking the
correctness of a userprovided gradient. Use the tao method "tao_fd_test"
to get an indication of whether your gradient is correct.
Note
This finite difference gradient evaluation can be set using the routine TaoSetGradientRoutine() or by using the command line option tao_fd_gradient
See Also
TaoSetGradientRoutine()
Level:advanced
Location:src/interface/fdiff.c
TAO Solver Index
Table of Contents