[petsc-users] Setting up a SNES problem using DMDASetLocalFunction/DMDASetLocalJacobian in PETSc 3.3

[Constantine Khroulev]

Hi,

While updating our code to work with PETSc 3.3 I noticed that (as far
as I can tell) there is no SNESDAFormFunction/SNESDAComputeJacobian
equivalent in 3.3.

I came up with a workaround (see below), but I am not sure if this is
legal. (See the "SNESSetFunction(snes, F, PETSC_NULL, PETSC_NULL)",
for example.)

What would you recommend?

/* begin code snippet */
{
  ierr = DMDACreate2d(..., &da); CHKERRQ(ierr);

  ierr = DMCreateGlobalVector(da, &F); CHKERRQ(ierr);
  ierr = DMCreateMatrix(da, "baij",  &J); CHKERRQ(ierr);

  ierr = SNESCreate(com, &snes);CHKERRQ(ierr);

  ierr = DMDASetLocalFunction(da,(DMDALocalFunction1)LocalFunction);CHKERRQ(ierr);
  ierr = DMDASetLocalJacobian(da,(DMDALocalFunction1)LocalJacobian);CHKERRQ(ierr);

#if I_HAVE_PETSC32==1
  ierr = SNESSetFunction(snes, F, SNESDAFormFunction, &ctx); CHKERRQ(ierr);
  ierr = SNESSetJacobian(snes, J, J, SNESDAComputeJacobian, &ctx);
CHKERRQ(ierr);
#else  /* PETSc 3.3 */
  ierr = SNESSetFunction(snes, F, PETSC_NULL, PETSC_NULL); CHKERRQ(ierr);
  ierr = SNESSetJacobian(snes, J, J, PETSC_NULL, PETSC_NULL); CHKERRQ(ierr);
  ierr = DMSetApplicationContext(da, &ctx); CHKERRQ(ierr);
#endif

  ierr = SNESSetDM(snes, da); CHKERRQ(ierr);

  ierr = SNESSetFromOptions(snes);CHKERRQ(ierr);
}
/* end code snippet */

-- 
Constantine