MatSNESMFSetReuseBase

Causes the base vector to be used for differencing even if the function provided to SNESSetFunction() is not the same as that provided to MatMFFDSetFunction().

Synopsis

#include "petscsnes.h" 
#include "petscdm.h"   
PetscErrorCode MatSNESMFSetReuseBase(Mat J, PetscBool use)

Logically Collective

Input Parameters

• J - the MATMFFD matrix

• use - if true always reuse the base vector instead of recomputing f(u) even if the function in the MATMFFD is not SNESComputeFunction()

Note

Care must be taken when using this routine to insure that the function provided to MatMFFDSetFunction(), call it F_MF() is compatible with with that provided to SNESSetFunction(), call it F_SNES(). That is, (F_MF(u + h*d) - F_SNES(u))/h has to approximate the derivative

Developer Note

This was provided for the MOOSE team who desired to have a SNESSetFunction() function that could change configurations (similar to variable switching) to contacts while the function provided to MatMFFDSetFunction() cannot. Except for the possibility of changing the configuration both functions compute the same mathematical function so the differencing makes sense.

See Also

MATMFFD, MatMFFDSetFunction(), SNESSetFunction(), MatCreateSNESMF(), MatSNESMFGetReuseBase()

Level

advanced

Location

src/snes/mf/snesmfj.c

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