petsc-3.13.6 2020-09-29
SNESObjectiveComputeFunctionDefaultFD
Computes the gradient of a user provided objective
Synopsis
PetscErrorCode SNESObjectiveComputeFunctionDefaultFD(SNES snes,Vec X,Vec F,void *ctx)
Collective on SNES
Input Parameter
| snes | - the SNES context
|
| X | - the state vector
|
| ctx | - the (ignored) function context
|
Output Parameter
F -the function value
Options Database Key
| -snes_fd_function_eps | - The differencing parameter
|
| -snes_fd_function | - Compute function from user provided objective with finite difference
|
Notes
SNESObjectiveComputeFunctionDefaultFD is similar in character to SNESComputeJacobianDefault.
Therefore, it should be used for debugging purposes only. Using it in conjunction with
SNESComputeJacobianDefault is excessively costly and produces a Jacobian that is quite
noisy. This is often necessary, but should be done with a grain of salt, even when debugging
small problems.
Note that this uses quadratic interpolation of the objective to form each value in the function.
See Also
SNESSetFunction(), SNESComputeObjective(), SNESComputeJacobianDefault()
Level
advanced
Location
src/snes/interface/snesob.c
Index of all SNES routines
Table of Contents for all manual pages
Index of all manual pages