petsc-dev 2014-02-02
TaoDefaultComputeGradient
computes the gradient using finite differences.
Synopsis
#include "petsctao.h"
PetscErrorCode TaoDefaultComputeGradient(Tao tao,Vec X,Vec G,void *dummy)
Collective on Tao
Input Parameters
| tao | - the Tao 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 large-scale applications, It can be useful in checking the
correctness of a user-provided 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/tao/interface/fdiff.c
Index of all Tao routines
Table of Contents for all manual pages
Index of all manual pages