/*@
SNESFASSetNumberSmoothDown - Sets the number of pre-smoothing steps to
use on all levels.
Logically Collective on SNES
Input Parameters:
+ snes - the multigrid context
- n - the number of smoothing steps
Options Database Key:
. -snes_fas_smoothdown <n> - Sets number of pre-smoothing steps
Level: advanced
.keywords: FAS, MG, smooth, down, pre-smoothing, steps, multigrid
.seealso: SNESFASSetNumberSmoothUp()
@*/
PetscErrorCode SNESFASSetNumberSmoothDown(SNES snes, PetscInt n)
{
SNES_FAS *fas = (SNES_FAS*)snes->data;
PetscErrorCode ierr = 0;
PetscFunctionBegin;
if (!fas->smoothd) {
ierr = SNESFASCycleCreateSmoother_Private(snes, &fas->smoothd);CHKERRQ(ierr);
}
ierr = SNESSetTolerances(fas->smoothd, fas->smoothd->abstol, fas->smoothd->rtol, fas->smoothd->stol, n, fas->smoothd->max_funcs);CHKERRQ(ierr);
fas->max_down_it = n;
if (fas->next) {
ierr = SNESFASSetNumberSmoothDown(fas->next, n);CHKERRQ(ierr);
}
PetscFunctionReturn(0);
}
PetscErrorCode SNESSetFromOptions_FAS(PetscOptions *PetscOptionsObject,SNES snes)
{
SNES_FAS *fas = (SNES_FAS*) snes->data;
PetscInt levels = 1;
PetscBool flg = PETSC_FALSE, upflg = PETSC_FALSE, downflg = PETSC_FALSE, monflg = PETSC_FALSE, galerkinflg = PETSC_FALSE,continuationflg = PETSC_FALSE;
PetscErrorCode ierr;
char monfilename[PETSC_MAX_PATH_LEN];
SNESFASType fastype;
const char *optionsprefix;
SNESLineSearch linesearch;
PetscInt m, n_up, n_down;
SNES next;
PetscBool isFine;
PetscFunctionBegin;
ierr = SNESFASCycleIsFine(snes, &isFine);CHKERRQ(ierr);
ierr = PetscOptionsHead(PetscOptionsObject,"SNESFAS Options-----------------------------------");CHKERRQ(ierr);
/* number of levels -- only process most options on the finest level */
if (isFine) {
ierr = PetscOptionsInt("-snes_fas_levels", "Number of Levels", "SNESFASSetLevels", levels, &levels, &flg);CHKERRQ(ierr);
if (!flg && snes->dm) {
ierr = DMGetRefineLevel(snes->dm,&levels);CHKERRQ(ierr);
levels++;
fas->usedmfornumberoflevels = PETSC_TRUE;
}
ierr = SNESFASSetLevels(snes, levels, NULL);CHKERRQ(ierr);
fastype = fas->fastype;
ierr = PetscOptionsEnum("-snes_fas_type","FAS correction type","SNESFASSetType",SNESFASTypes,(PetscEnum)fastype,(PetscEnum*)&fastype,&flg);CHKERRQ(ierr);
if (flg) {
ierr = SNESFASSetType(snes, fastype);CHKERRQ(ierr);
}
ierr = SNESGetOptionsPrefix(snes, &optionsprefix);CHKERRQ(ierr);
ierr = PetscOptionsInt("-snes_fas_cycles","Number of cycles","SNESFASSetCycles",fas->n_cycles,&m,&flg);CHKERRQ(ierr);
if (flg) {
ierr = SNESFASSetCycles(snes, m);CHKERRQ(ierr);
}
ierr = PetscOptionsBool("-snes_fas_continuation","Corrected grid-sequence continuation","SNESFASSetContinuation",fas->continuation,&continuationflg,&flg);CHKERRQ(ierr);
if (flg) {
ierr = SNESFASSetContinuation(snes,continuationflg);CHKERRQ(ierr);
}
ierr = PetscOptionsBool("-snes_fas_galerkin", "Form coarse problems with Galerkin","SNESFASSetGalerkin",fas->galerkin,&galerkinflg,&flg);CHKERRQ(ierr);
if (flg) {
ierr = SNESFASSetGalerkin(snes, galerkinflg);CHKERRQ(ierr);
}
if (fas->fastype == SNES_FAS_FULL) {
ierr = PetscOptionsBool("-snes_fas_full_downsweep","Smooth on the initial upsweep for full FAS cycles","SNESFASFullSetDownSweep",fas->full_downsweep,&fas->full_downsweep,&flg);CHKERRQ(ierr);
if (flg) {SNESFASFullSetDownSweep(snes,fas->full_downsweep);CHKERRQ(ierr);}
}
ierr = PetscOptionsInt("-snes_fas_smoothup","Number of post-smoothing steps","SNESFASSetNumberSmoothUp",fas->max_up_it,&n_up,&upflg);CHKERRQ(ierr);
ierr = PetscOptionsInt("-snes_fas_smoothdown","Number of pre-smoothing steps","SNESFASSetNumberSmoothDown",fas->max_down_it,&n_down,&downflg);CHKERRQ(ierr);
ierr = PetscOptionsString("-snes_fas_monitor","Monitor FAS progress","SNESFASSetMonitor","stdout",monfilename,PETSC_MAX_PATH_LEN,&monflg);CHKERRQ(ierr);
if (monflg) ierr = SNESFASSetMonitor(snes, PETSC_TRUE);CHKERRQ(ierr);
flg = PETSC_FALSE;
monflg = PETSC_TRUE;
ierr = PetscOptionsBool("-snes_fas_log","Log times for each FAS level","SNESFASSetLog",monflg,&monflg,&flg);CHKERRQ(ierr);
if (flg) {ierr = SNESFASSetLog(snes,monflg);CHKERRQ(ierr);}
}
ierr = PetscOptionsTail();CHKERRQ(ierr);
/* setup from the determined types if there is no pointwise procedure or smoother defined */
if (upflg) {
ierr = SNESFASSetNumberSmoothUp(snes,n_up);CHKERRQ(ierr);
}
if (downflg) {
ierr = SNESFASSetNumberSmoothDown(snes,n_down);CHKERRQ(ierr);
}
/* set up the default line search for coarse grid corrections */
if (fas->fastype == SNES_FAS_ADDITIVE) {
if (!snes->linesearch) {
ierr = SNESGetLineSearch(snes, &linesearch);CHKERRQ(ierr);
ierr = SNESLineSearchSetType(linesearch, SNESLINESEARCHL2);CHKERRQ(ierr);
}
}
ierr = SNESFASCycleGetCorrection(snes, &next);CHKERRQ(ierr);
/* recursive option setting for the smoothers */
if (next) {ierr = SNESSetFromOptions(next);CHKERRQ(ierr);}
PetscFunctionReturn(0);
}
PETSC_EXTERN void PETSC_STDCALL snesfassetnumbersmoothdown_(SNES snes,PetscInt *n, int *__ierr ){
*__ierr = SNESFASSetNumberSmoothDown(
(SNES)PetscToPointer((snes) ),*n);
}