#include "petscsnes.h" PetscErrorCode SNESGetFunction(SNES snes,Vec *r,PetscErrorCode (**f)(SNES,Vec,Vec,void*),void **ctx)Not Collective, but Vec is parallel if SNES is parallel. Collective if Vec is requested, but has not been created yet.
|r||- the vector that is used to store residuals (or NULL if you don't want it)|
|f||- the function (or NULL if you don't want it); see SNESFunction for calling sequence details|
|ctx||- the function context (or NULL if you don't want it)|
Notes: The vector r DOES NOT, in general contain the current value of the SNES nonlinear function