void MGinit( const MgSmootherType &mg_smoother_type, const unsigned &levelMax ){
KSPCreate(PETSC_COMM_WORLD,&_ksp);
KSPGetPC(_ksp,&_pc);
PCSetType(_pc,PCMG);
PCMGSetLevels(_pc,levelMax,NULL);
if( mg_smoother_type == FULL ){
PCMGSetType(_pc, PC_MG_FULL);
}
else if( mg_smoother_type == MULTIPLICATIVE ){
PCMGSetType(_pc, PC_MG_MULTIPLICATIVE);
}
else if( mg_smoother_type == ADDITIVE ){
PCMGSetType(_pc, PC_MG_ADDITIVE);
}
else if( mg_smoother_type == KASKADE ){
PCMGSetType(_pc, PC_MG_KASKADE);
}
else{
std::cout <<"Wrong mg_type for PETSCsolve()"<<std::endl;
abort();
}
};
PetscErrorCode PETSCSNES_DLLEXPORT DMMGSetUpLevel(DMMG *dmmg,KSP ksp,PetscInt nlevels)
{
PetscErrorCode ierr;
PetscInt i;
PC pc;
PetscTruth ismg,ismf,isshell,ismffd;
KSP lksp; /* solver internal to the multigrid preconditioner */
MPI_Comm *comms;
PetscFunctionBegin;
if (!dmmg) SETERRQ(PETSC_ERR_ARG_NULL,"Passing null as DMMG");
/* use fgmres on outer iteration by default */
ierr = KSPSetType(ksp,KSPFGMRES);CHKERRQ(ierr);
ierr = KSPGetPC(ksp,&pc);CHKERRQ(ierr);
ierr = PCSetType(pc,PCMG);CHKERRQ(ierr);
ierr = PetscMalloc(nlevels*sizeof(MPI_Comm),&comms);CHKERRQ(ierr);
for (i=0; i<nlevels; i++) {
comms[i] = dmmg[i]->comm;
}
ierr = PCMGSetLevels(pc,nlevels,comms);CHKERRQ(ierr);
ierr = PetscFree(comms);CHKERRQ(ierr);
ierr = PCMGSetType(pc,PC_MG_FULL);CHKERRQ(ierr);
ierr = PetscTypeCompare((PetscObject)pc,PCMG,&ismg);CHKERRQ(ierr);
if (ismg) {
/* set solvers for each level */
for (i=0; i<nlevels; i++) {
if (i < nlevels-1) { /* don't set for finest level, they are set in PCApply_MG()*/
ierr = PCMGSetX(pc,i,dmmg[i]->x);CHKERRQ(ierr);
ierr = PCMGSetRhs(pc,i,dmmg[i]->b);CHKERRQ(ierr);
}
if (i > 0) {
ierr = PCMGSetR(pc,i,dmmg[i]->r);CHKERRQ(ierr);
}
/* If using a matrix free multiply and did not provide an explicit matrix to build
the preconditioner then must use no preconditioner
*/
ierr = PetscTypeCompare((PetscObject)dmmg[i]->B,MATSHELL,&isshell);CHKERRQ(ierr);
ierr = PetscTypeCompare((PetscObject)dmmg[i]->B,MATDAAD,&ismf);CHKERRQ(ierr);
ierr = PetscTypeCompare((PetscObject)dmmg[i]->B,MATMFFD,&ismffd);CHKERRQ(ierr);
if (isshell || ismf || ismffd) {
PC lpc;
ierr = PCMGGetSmoother(pc,i,&lksp);CHKERRQ(ierr);
ierr = KSPGetPC(lksp,&lpc);CHKERRQ(ierr);
ierr = PCSetType(lpc,PCNONE);CHKERRQ(ierr);
}
}
/* Set interpolation/restriction between levels */
for (i=1; i<nlevels; i++) {
ierr = PCMGSetInterpolation(pc,i,dmmg[i]->R);CHKERRQ(ierr);
ierr = PCMGSetRestriction(pc,i,dmmg[i]->R);CHKERRQ(ierr);
}
}
PetscFunctionReturn(0);
}
int main(int Argc,char **Args)
{
PetscInt x_mesh = 15,levels = 3,cycles = 1,use_jacobi = 0;
PetscInt i,smooths = 1,*N,its;
PetscErrorCode ierr;
PCMGType am = PC_MG_MULTIPLICATIVE;
Mat cmat,mat[20],fmat;
KSP cksp,ksp[20],kspmg;
PetscReal e[3]; /* l_2 error,max error, residual */
const char *shellname;
Vec x,solution,X[20],R[20],B[20];
PC pcmg,pc;
PetscBool flg;
PetscInitialize(&Argc,&Args,(char*)0,help);
ierr = PetscOptionsGetInt(NULL,"-x",&x_mesh,NULL);CHKERRQ(ierr);
ierr = PetscOptionsGetInt(NULL,"-l",&levels,NULL);CHKERRQ(ierr);
ierr = PetscOptionsGetInt(NULL,"-c",&cycles,NULL);CHKERRQ(ierr);
ierr = PetscOptionsGetInt(NULL,"-smooths",&smooths,NULL);CHKERRQ(ierr);
ierr = PetscOptionsHasName(NULL,"-a",&flg);CHKERRQ(ierr);
if (flg) am = PC_MG_ADDITIVE;
ierr = PetscOptionsHasName(NULL,"-f",&flg);CHKERRQ(ierr);
if (flg) am = PC_MG_FULL;
ierr = PetscOptionsHasName(NULL,"-j",&flg);CHKERRQ(ierr);
if (flg) use_jacobi = 1;
ierr = PetscMalloc1(levels,&N);CHKERRQ(ierr);
N[0] = x_mesh;
for (i=1; i<levels; i++) {
N[i] = N[i-1]/2;
if (N[i] < 1) SETERRQ(PETSC_COMM_WORLD,1,"Too many levels");
}
ierr = Create1dLaplacian(N[levels-1],&cmat);CHKERRQ(ierr);
ierr = KSPCreate(PETSC_COMM_WORLD,&kspmg);CHKERRQ(ierr);
ierr = KSPGetPC(kspmg,&pcmg);CHKERRQ(ierr);
ierr = KSPSetFromOptions(kspmg);CHKERRQ(ierr);
ierr = PCSetType(pcmg,PCMG);CHKERRQ(ierr);
ierr = PCMGSetLevels(pcmg,levels,NULL);CHKERRQ(ierr);
ierr = PCMGSetType(pcmg,am);CHKERRQ(ierr);
ierr = PCMGGetCoarseSolve(pcmg,&cksp);CHKERRQ(ierr);
ierr = KSPSetOperators(cksp,cmat,cmat);CHKERRQ(ierr);
ierr = KSPGetPC(cksp,&pc);CHKERRQ(ierr);
ierr = PCSetType(pc,PCLU);CHKERRQ(ierr);
ierr = KSPSetType(cksp,KSPPREONLY);CHKERRQ(ierr);
/* zero is finest level */
for (i=0; i<levels-1; i++) {
ierr = PCMGSetResidual(pcmg,levels - 1 - i,residual,(Mat)0);CHKERRQ(ierr);
ierr = MatCreateShell(PETSC_COMM_WORLD,N[i+1],N[i],N[i+1],N[i],(void*)0,&mat[i]);CHKERRQ(ierr);
ierr = MatShellSetOperation(mat[i],MATOP_MULT,(void (*)(void))restrct);CHKERRQ(ierr);
ierr = MatShellSetOperation(mat[i],MATOP_MULT_TRANSPOSE_ADD,(void (*)(void))interpolate);CHKERRQ(ierr);
ierr = PCMGSetInterpolation(pcmg,levels - 1 - i,mat[i]);CHKERRQ(ierr);
ierr = PCMGSetRestriction(pcmg,levels - 1 - i,mat[i]);CHKERRQ(ierr);
ierr = PCMGSetCyclesOnLevel(pcmg,levels - 1 - i,cycles);CHKERRQ(ierr);
/* set smoother */
ierr = PCMGGetSmoother(pcmg,levels - 1 - i,&ksp[i]);CHKERRQ(ierr);
ierr = KSPGetPC(ksp[i],&pc);CHKERRQ(ierr);
ierr = PCSetType(pc,PCSHELL);CHKERRQ(ierr);
ierr = PCShellSetName(pc,"user_precond");CHKERRQ(ierr);
ierr = PCShellGetName(pc,&shellname);CHKERRQ(ierr);
ierr = PetscPrintf(PETSC_COMM_WORLD,"level=%D, PCShell name is %s\n",i,shellname);CHKERRQ(ierr);
/* this is a dummy! since KSP requires a matrix passed in */
ierr = KSPSetOperators(ksp[i],mat[i],mat[i]);CHKERRQ(ierr);
/*
We override the matrix passed in by forcing it to use Richardson with
a user provided application. This is non-standard and this practice
should be avoided.
*/
ierr = PCShellSetApplyRichardson(pc,gauss_seidel);CHKERRQ(ierr);
if (use_jacobi) {
ierr = PCShellSetApplyRichardson(pc,jacobi);CHKERRQ(ierr);
}
ierr = KSPSetType(ksp[i],KSPRICHARDSON);CHKERRQ(ierr);
ierr = KSPSetInitialGuessNonzero(ksp[i],PETSC_TRUE);CHKERRQ(ierr);
ierr = KSPSetTolerances(ksp[i],PETSC_DEFAULT,PETSC_DEFAULT,PETSC_DEFAULT,smooths);CHKERRQ(ierr);
ierr = VecCreateSeq(PETSC_COMM_SELF,N[i],&x);CHKERRQ(ierr);
X[levels - 1 - i] = x;
if (i > 0) {
ierr = PCMGSetX(pcmg,levels - 1 - i,x);CHKERRQ(ierr);
}
ierr = VecCreateSeq(PETSC_COMM_SELF,N[i],&x);CHKERRQ(ierr);
B[levels -1 - i] = x;
if (i > 0) {
ierr = PCMGSetRhs(pcmg,levels - 1 - i,x);CHKERRQ(ierr);
}
ierr = VecCreateSeq(PETSC_COMM_SELF,N[i],&x);CHKERRQ(ierr);
R[levels - 1 - i] = x;
ierr = PCMGSetR(pcmg,levels - 1 - i,x);CHKERRQ(ierr);
}
/* create coarse level vectors */
ierr = VecCreateSeq(PETSC_COMM_SELF,N[levels-1],&x);CHKERRQ(ierr);
ierr = PCMGSetX(pcmg,0,x);CHKERRQ(ierr); X[0] = x;
ierr = VecCreateSeq(PETSC_COMM_SELF,N[levels-1],&x);CHKERRQ(ierr);
ierr = PCMGSetRhs(pcmg,0,x);CHKERRQ(ierr); B[0] = x;
/* create matrix multiply for finest level */
ierr = MatCreateShell(PETSC_COMM_WORLD,N[0],N[0],N[0],N[0],(void*)0,&fmat);CHKERRQ(ierr);
ierr = MatShellSetOperation(fmat,MATOP_MULT,(void (*)(void))amult);CHKERRQ(ierr);
ierr = KSPSetOperators(kspmg,fmat,fmat);CHKERRQ(ierr);
ierr = CalculateSolution(N[0],&solution);CHKERRQ(ierr);
ierr = CalculateRhs(B[levels-1]);CHKERRQ(ierr);
ierr = VecSet(X[levels-1],0.0);CHKERRQ(ierr);
ierr = residual((Mat)0,B[levels-1],X[levels-1],R[levels-1]);CHKERRQ(ierr);
ierr = CalculateError(solution,X[levels-1],R[levels-1],e);CHKERRQ(ierr);
ierr = PetscPrintf(PETSC_COMM_SELF,"l_2 error %g max error %g resi %g\n",(double)e[0],(double)e[1],(double)e[2]);CHKERRQ(ierr);
ierr = KSPSolve(kspmg,B[levels-1],X[levels-1]);CHKERRQ(ierr);
ierr = KSPGetIterationNumber(kspmg,&its);CHKERRQ(ierr);
ierr = residual((Mat)0,B[levels-1],X[levels-1],R[levels-1]);CHKERRQ(ierr);
ierr = CalculateError(solution,X[levels-1],R[levels-1],e);CHKERRQ(ierr);
ierr = PetscPrintf(PETSC_COMM_SELF,"its %D l_2 error %g max error %g resi %g\n",its,(double)e[0],(double)e[1],(double)e[2]);CHKERRQ(ierr);
ierr = PetscFree(N);CHKERRQ(ierr);
ierr = VecDestroy(&solution);CHKERRQ(ierr);
/* note we have to keep a list of all vectors allocated, this is
not ideal, but putting it in MGDestroy is not so good either*/
for (i=0; i<levels; i++) {
ierr = VecDestroy(&X[i]);CHKERRQ(ierr);
ierr = VecDestroy(&B[i]);CHKERRQ(ierr);
if (i) {ierr = VecDestroy(&R[i]);CHKERRQ(ierr);}
}
for (i=0; i<levels-1; i++) {
ierr = MatDestroy(&mat[i]);CHKERRQ(ierr);
}
ierr = MatDestroy(&cmat);CHKERRQ(ierr);
ierr = MatDestroy(&fmat);CHKERRQ(ierr);
ierr = KSPDestroy(&kspmg);CHKERRQ(ierr);
ierr = PetscFinalize();
return 0;
}
PetscErrorCode PCSetFromOptions_MG(PetscOptionItems *PetscOptionsObject,PC pc)
{
PetscErrorCode ierr;
PetscInt m,levels = 1,cycles;
PetscBool flg,set;
PC_MG *mg = (PC_MG*)pc->data;
PC_MG_Levels **mglevels;
PCMGType mgtype;
PCMGCycleType mgctype;
PetscFunctionBegin;
ierr = PetscOptionsHead(PetscOptionsObject,"Multigrid options");CHKERRQ(ierr);
if (!mg->levels) {
ierr = PetscOptionsInt("-pc_mg_levels","Number of Levels","PCMGSetLevels",levels,&levels,&flg);CHKERRQ(ierr);
if (!flg && pc->dm) {
ierr = DMGetRefineLevel(pc->dm,&levels);CHKERRQ(ierr);
levels++;
mg->usedmfornumberoflevels = PETSC_TRUE;
}
ierr = PCMGSetLevels(pc,levels,NULL);CHKERRQ(ierr);
}
mglevels = mg->levels;
mgctype = (PCMGCycleType) mglevels[0]->cycles;
ierr = PetscOptionsEnum("-pc_mg_cycle_type","V cycle or for W-cycle","PCMGSetCycleType",PCMGCycleTypes,(PetscEnum)mgctype,(PetscEnum*)&mgctype,&flg);CHKERRQ(ierr);
if (flg) {
ierr = PCMGSetCycleType(pc,mgctype);CHKERRQ(ierr);
}
flg = PETSC_FALSE;
ierr = PetscOptionsBool("-pc_mg_galerkin","Use Galerkin process to compute coarser operators","PCMGSetGalerkin",flg,&flg,&set);CHKERRQ(ierr);
if (set) {
ierr = PCMGSetGalerkin(pc,flg);CHKERRQ(ierr);
}
ierr = PetscOptionsInt("-pc_mg_smoothup","Number of post-smoothing steps","PCMGSetNumberSmoothUp",mg->default_smoothu,&m,&flg);CHKERRQ(ierr);
if (flg) {
ierr = PCMGSetNumberSmoothUp(pc,m);CHKERRQ(ierr);
}
ierr = PetscOptionsInt("-pc_mg_smoothdown","Number of pre-smoothing steps","PCMGSetNumberSmoothDown",mg->default_smoothd,&m,&flg);CHKERRQ(ierr);
if (flg) {
ierr = PCMGSetNumberSmoothDown(pc,m);CHKERRQ(ierr);
}
mgtype = mg->am;
ierr = PetscOptionsEnum("-pc_mg_type","Multigrid type","PCMGSetType",PCMGTypes,(PetscEnum)mgtype,(PetscEnum*)&mgtype,&flg);CHKERRQ(ierr);
if (flg) {
ierr = PCMGSetType(pc,mgtype);CHKERRQ(ierr);
}
if (mg->am == PC_MG_MULTIPLICATIVE) {
ierr = PetscOptionsInt("-pc_mg_multiplicative_cycles","Number of cycles for each preconditioner step","PCMGMultiplicativeSetCycles",mg->cyclesperpcapply,&cycles,&flg);CHKERRQ(ierr);
if (flg) {
ierr = PCMGMultiplicativeSetCycles(pc,cycles);CHKERRQ(ierr);
}
}
flg = PETSC_FALSE;
ierr = PetscOptionsBool("-pc_mg_log","Log times for each multigrid level","None",flg,&flg,NULL);CHKERRQ(ierr);
if (flg) {
PetscInt i;
char eventname[128];
if (!mglevels) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_WRONGSTATE,"Must set MG levels before calling");
levels = mglevels[0]->levels;
for (i=0; i<levels; i++) {
sprintf(eventname,"MGSetup Level %d",(int)i);
ierr = PetscLogEventRegister(eventname,((PetscObject)pc)->classid,&mglevels[i]->eventsmoothsetup);CHKERRQ(ierr);
sprintf(eventname,"MGSmooth Level %d",(int)i);
ierr = PetscLogEventRegister(eventname,((PetscObject)pc)->classid,&mglevels[i]->eventsmoothsolve);CHKERRQ(ierr);
if (i) {
sprintf(eventname,"MGResid Level %d",(int)i);
ierr = PetscLogEventRegister(eventname,((PetscObject)pc)->classid,&mglevels[i]->eventresidual);CHKERRQ(ierr);
sprintf(eventname,"MGInterp Level %d",(int)i);
ierr = PetscLogEventRegister(eventname,((PetscObject)pc)->classid,&mglevels[i]->eventinterprestrict);CHKERRQ(ierr);
}
}
#if defined(PETSC_USE_LOG)
{
const char *sname = "MG Apply";
PetscStageLog stageLog;
PetscInt st;
PetscFunctionBegin;
ierr = PetscLogGetStageLog(&stageLog);CHKERRQ(ierr);
for (st = 0; st < stageLog->numStages; ++st) {
PetscBool same;
ierr = PetscStrcmp(stageLog->stageInfo[st].name, sname, &same);CHKERRQ(ierr);
if (same) mg->stageApply = st;
}
if (!mg->stageApply) {
ierr = PetscLogStageRegister(sname, &mg->stageApply);CHKERRQ(ierr);
}
}
#endif
}
ierr = PetscOptionsTail();CHKERRQ(ierr);
PetscFunctionReturn(0);
}
/*@C
PCMGSetLevels - Sets the number of levels to use with MG.
Must be called before any other MG routine.
Logically Collective on PC
Input Parameters:
+ pc - the preconditioner context
. levels - the number of levels
- comms - optional communicators for each level; this is to allow solving the coarser problems
on smaller sets of processors. Use NULL_OBJECT for default in Fortran
Level: intermediate
Notes:
If the number of levels is one then the multigrid uses the -mg_levels prefix
for setting the level options rather than the -mg_coarse prefix.
.keywords: MG, set, levels, multigrid
.seealso: PCMGSetType(), PCMGGetLevels()
@*/
PetscErrorCode PCMGSetLevels(PC pc,PetscInt levels,MPI_Comm *comms)
{
PetscErrorCode ierr;
PC_MG *mg = (PC_MG*)pc->data;
MPI_Comm comm;
PC_MG_Levels **mglevels = mg->levels;
PCMGType mgtype = mg->am;
PetscInt mgctype = (PetscInt) PC_MG_CYCLE_V;
PetscInt i;
PetscMPIInt size;
const char *prefix;
PC ipc;
PetscInt n;
PetscFunctionBegin;
PetscValidHeaderSpecific(pc,PC_CLASSID,1);
PetscValidLogicalCollectiveInt(pc,levels,2);
ierr = PetscObjectGetComm((PetscObject)pc,&comm);CHKERRQ(ierr);
if (mg->nlevels == levels) PetscFunctionReturn(0);
if (mglevels) {
mgctype = mglevels[0]->cycles;
/* changing the number of levels so free up the previous stuff */
ierr = PCReset_MG(pc);CHKERRQ(ierr);
n = mglevels[0]->levels;
for (i=0; i<n; i++) {
if (mglevels[i]->smoothd != mglevels[i]->smoothu) {
ierr = KSPDestroy(&mglevels[i]->smoothd);CHKERRQ(ierr);
}
ierr = KSPDestroy(&mglevels[i]->smoothu);CHKERRQ(ierr);
ierr = PetscFree(mglevels[i]);CHKERRQ(ierr);
}
ierr = PetscFree(mg->levels);CHKERRQ(ierr);
}
mg->nlevels = levels;
ierr = PetscMalloc1(levels,&mglevels);CHKERRQ(ierr);
ierr = PetscLogObjectMemory((PetscObject)pc,levels*(sizeof(PC_MG*)));CHKERRQ(ierr);
ierr = PCGetOptionsPrefix(pc,&prefix);CHKERRQ(ierr);
mg->stageApply = 0;
for (i=0; i<levels; i++) {
ierr = PetscNewLog(pc,&mglevels[i]);CHKERRQ(ierr);
mglevels[i]->level = i;
mglevels[i]->levels = levels;
mglevels[i]->cycles = mgctype;
mg->default_smoothu = 2;
mg->default_smoothd = 2;
mglevels[i]->eventsmoothsetup = 0;
mglevels[i]->eventsmoothsolve = 0;
mglevels[i]->eventresidual = 0;
mglevels[i]->eventinterprestrict = 0;
if (comms) comm = comms[i];
ierr = KSPCreate(comm,&mglevels[i]->smoothd);CHKERRQ(ierr);
ierr = KSPSetErrorIfNotConverged(mglevels[i]->smoothd,pc->erroriffailure);CHKERRQ(ierr);
ierr = PetscObjectIncrementTabLevel((PetscObject)mglevels[i]->smoothd,(PetscObject)pc,levels-i);CHKERRQ(ierr);
ierr = KSPSetOptionsPrefix(mglevels[i]->smoothd,prefix);CHKERRQ(ierr);
ierr = PetscObjectComposedDataSetInt((PetscObject) mglevels[i]->smoothd, PetscMGLevelId, mglevels[i]->level);CHKERRQ(ierr);
if (i || levels == 1) {
char tprefix[128];
ierr = KSPSetType(mglevels[i]->smoothd,KSPCHEBYSHEV);CHKERRQ(ierr);
ierr = KSPSetConvergenceTest(mglevels[i]->smoothd,KSPConvergedSkip,NULL,NULL);CHKERRQ(ierr);
ierr = KSPSetNormType(mglevels[i]->smoothd,KSP_NORM_NONE);CHKERRQ(ierr);
ierr = KSPGetPC(mglevels[i]->smoothd,&ipc);CHKERRQ(ierr);
ierr = PCSetType(ipc,PCSOR);CHKERRQ(ierr);
ierr = KSPSetTolerances(mglevels[i]->smoothd,PETSC_DEFAULT,PETSC_DEFAULT,PETSC_DEFAULT, mg->default_smoothd);CHKERRQ(ierr);
sprintf(tprefix,"mg_levels_%d_",(int)i);
ierr = KSPAppendOptionsPrefix(mglevels[i]->smoothd,tprefix);CHKERRQ(ierr);
} else {
ierr = KSPAppendOptionsPrefix(mglevels[0]->smoothd,"mg_coarse_");CHKERRQ(ierr);
/* coarse solve is (redundant) LU by default; set shifttype NONZERO to avoid annoying zero-pivot in LU preconditioner */
ierr = KSPSetType(mglevels[0]->smoothd,KSPPREONLY);CHKERRQ(ierr);
ierr = KSPGetPC(mglevels[0]->smoothd,&ipc);CHKERRQ(ierr);
ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
if (size > 1) {
ierr = PCSetType(ipc,PCREDUNDANT);CHKERRQ(ierr);
} else {
ierr = PCSetType(ipc,PCLU);CHKERRQ(ierr);
}
ierr = PCFactorSetShiftType(ipc,MAT_SHIFT_INBLOCKS);CHKERRQ(ierr);
}
ierr = PetscLogObjectParent((PetscObject)pc,(PetscObject)mglevels[i]->smoothd);CHKERRQ(ierr);
mglevels[i]->smoothu = mglevels[i]->smoothd;
mg->rtol = 0.0;
mg->abstol = 0.0;
mg->dtol = 0.0;
mg->ttol = 0.0;
mg->cyclesperpcapply = 1;
}
mg->levels = mglevels;
ierr = PCMGSetType(pc,mgtype);CHKERRQ(ierr);
PetscFunctionReturn(0);
}
void PETScMGSolver_UpdateSolvers( PETScMGSolver* self ) {
PETScMGSolver_Level* level;
PC pc;
KSP levelKSP;
PC levelPC;
PetscErrorCode ec;
unsigned l_i;
PetscTruth smoothers_differ, flag;
PetscMPIInt size;
MPI_Comm comm;
assert( self && Stg_CheckType( self, PETScMGSolver ) );
ec = KSPGetPC( self->mgData->ksp, &pc );
CheckPETScError( ec );
ec = PCMGSetLevels( pc, self->nLevels, PETSC_NULL );
CheckPETScError( ec );
ec = PCMGSetType( pc, PC_MG_MULTIPLICATIVE );
CheckPETScError( ec );
ec=PetscOptionsGetTruth( PETSC_NULL, "-pc_mg_different_smoothers", &smoothers_differ, &flag ); CheckPETScError(ec);
ec=PetscObjectGetComm( (PetscObject)pc, &comm ); CheckPETScError(ec);
MPI_Comm_size( comm, &size );
for( l_i = 1; l_i < self->nLevels; l_i++ ) {
level = self->levels + l_i;
printf("Configuring MG level %d \n", l_i );
ec = PCMGGetSmootherDown( pc, l_i, &levelKSP );
CheckPETScError( ec );
if(smoothers_differ==PETSC_TRUE) { ec=KSPAppendOptionsPrefix( levelKSP, "down_" ); CheckPETScError(ec); }
ec = KSPSetType( levelKSP, KSPRICHARDSON ); CheckPETScError( ec );
ec = KSPGetPC( levelKSP, &levelPC ); CheckPETScError( ec );
if(size==1) {
ec = PCSetType( levelPC, PCSOR ); CheckPETScError( ec );
}
/* This does not work - bug with the order the operators are created I guess */
/* For parallel jobs you best bet is to use the command line args and let petsc work it out */
/*
else {
KSP *sub_ksp;
PetscInt k, n_local, first_local;
PC sub_pc;
PCSetType( levelPC, PCBJACOBI );
KSPSetUp( levelKSP );
PCBJacobiGetSubKSP( levelPC, &n_local,&first_local,&sub_ksp);
for(k=0;k<n_local;k++ ) {
KSPSetType( sub_ksp[k], KSPFGMRES );
KSPGetPC( sub_ksp[k], &sub_pc );
PCSetType( sub_pc, PCSOR );
}
}
*/
ec = KSPSetTolerances( levelKSP, PETSC_DEFAULT, PETSC_DEFAULT, PETSC_DEFAULT, level->nDownIts ); CheckPETScError( ec );
if( l_i == self->nLevels - 1 ) {
ec = KSPSetInitialGuessNonzero( levelKSP, PETSC_TRUE ); CheckPETScError( ec );
}
else { ec = KSPSetInitialGuessNonzero( levelKSP, PETSC_FALSE ); CheckPETScError( ec ); }
ec = PCMGGetSmootherUp( pc, l_i, &levelKSP ); CheckPETScError( ec );
if(smoothers_differ==PETSC_TRUE) { ec=KSPAppendOptionsPrefix( levelKSP, "up_" ); CheckPETScError(ec); }
ec = KSPSetType( levelKSP, KSPRICHARDSON ); CheckPETScError( ec );
ec = KSPGetPC( levelKSP, &levelPC ); CheckPETScError( ec );
if(size==1) {
ec = PCSetType( levelPC, PCSOR ); CheckPETScError( ec );
}
ec = KSPSetTolerances( levelKSP, PETSC_DEFAULT, PETSC_DEFAULT, PETSC_DEFAULT, level->nUpIts ); CheckPETScError( ec );
ec = KSPSetInitialGuessNonzero( levelKSP, PETSC_TRUE ); CheckPETScError( ec );
ec = PCMGSetCyclesOnLevel( pc, l_i, level->nCycles ); CheckPETScError( ec );
}
}
PETSC_EXTERN void PETSC_STDCALL pcmgsettype_(PC pc,PCMGType *form, int *__ierr ){
*__ierr = PCMGSetType(
(PC)PetscToPointer((pc) ),*form);
}
int
main(int argc, char** argv) {
int levels = 4;
int mg_levels = 3;
PetscInitialize(&argc, &argv, PETSC_NULL, PETSC_NULL);
construct_operator(&problem, levels);
KSP ksp;
PC pc;
KSPCreate(PETSC_COMM_WORLD, &ksp);
KSPSetOperators(ksp, problem.A, problem.A, SAME_PRECONDITIONER);
KSPSetType(ksp, KSPRICHARDSON);
if (1) {
KSPGetPC(ksp, &pc);
PCSetType(pc, PCMG);
PCMGSetLevels(pc, mg_levels, NULL);
PCMGSetGalerkin(pc);
PCMGSetType(pc, PC_MG_MULTIPLICATIVE);
PCMGSetCycleType(pc, PC_MG_CYCLE_V);
int ii;
for (ii=0; ii<mg_levels; ii++) {
if (ii == 0) {
KSP smooth_ksp;
PCMGGetSmoother(pc, ii, &smooth_ksp);
KSPSetType(smooth_ksp, KSPPREONLY);
PC smooth_pc;
KSPGetPC(smooth_ksp, &smooth_pc);
PCSetType(smooth_pc, PCLU);
} else {
// set up the smoother.
KSP smooth_ksp;
PC smooth_pc;
PCMGGetSmoother(pc, ii, &smooth_ksp);
KSPSetType(smooth_ksp, KSPRICHARDSON);
KSPRichardsonSetScale(smooth_ksp, 2./3.);
KSPGetPC(smooth_ksp, &smooth_pc);
PCSetType(smooth_pc, PCJACOBI);
KSPSetTolerances(smooth_ksp, PETSC_DEFAULT, PETSC_DEFAULT, PETSC_DEFAULT, 2);
//set up the interpolation operator
Mat prolongation;
construct_prolongation_operator(ii+1+levels-mg_levels, &prolongation);
PCMGSetInterpolation(pc, ii, prolongation);
MatScale(prolongation, 1./2.);
Mat restriction;
MatTranspose(prolongation, &restriction);
PCMGSetRestriction(pc, ii, prolongation);
MatDestroy(prolongation);
MatDestroy(restriction);
}
}
} else {
KSPGetPC(ksp, &pc);
PCSetType(pc, PCJACOBI);
}
//*/
/*
if (0) {
KSPSetType(ksp, KSPRICHARDSON);
KSPRichardsonSetScale(ksp, 2./3.);
KSPGetPC(ksp, &pc);
PCSetType(pc, PCJACOBI);
} else {
PetscOptionsInsertString("-ksp_type richardson");
PetscOptionsInsertString("-ksp_richardson_scale 0.666666666666666666");
PetscOptionsInsertString("-pc_type jacobi");
}
//*/
KSPSetInitialGuessNonzero(ksp, PETSC_TRUE);
KSPSetFromOptions(ksp);
KSPSetUp(ksp);
//VecView(problem.x, PETSC_VIEWER_STDOUT_WORLD);
{
//CHKERR(PCApply(pc, problem.b, problem.x));
CHKERR(KSPSolve(ksp, problem.b, problem.x));
KSPConvergedReason reason;
CHKERR(KSPGetConvergedReason(ksp, &reason));
printf("KSPConvergedReason: %d\n", reason);
PetscInt its;
CHKERR(KSPGetIterationNumber(ksp, &its));
printf("Num iterations: %d\n", its);
}
//compute_residual_norm(&problem);
VecView(problem.x, PETSC_VIEWER_STDOUT_WORLD);
PetscFinalize();
return 0;
}
void StgFEM_GMG_SolverSetup( void* _solver, void* _stokesSLE ) {
StgFEM_GMG* self = StgFEM_GMG_selfPointer;
Stokes_SLE_UzawaSolver* solver = (Stokes_SLE_UzawaSolver*)_solver;
Stokes_SLE* sle = (Stokes_SLE*)_stokesSLE;
KSP ksp = solver->velSolver;
PC pc;
int ii;
Journal_DPrintf( solver->debug, "In %s:\n", __func__ );
Stream_IndentBranch( StgFEM_Debug );
KSPSetType( ksp, KSPFGMRES );
KSPGetPC( ksp, &pc );
PCSetType( pc, PCMG );
PCMGSetLevels( pc, self->numLevels, PETSC_NULL );
PCMGSetType( pc, PC_MG_MULTIPLICATIVE );
#if ((PETSC_VERSION_MAJOR==3) && (PETSC_VERSION_MINOR>=2) )
PCMGSetGalerkin( pc, PETSC_TRUE );
#else
PCMGSetGalerkin( pc );
#endif
/* Set the operators for each level. */
{
Mat *pOps, *rOps;
MGOpGenerator_SetNumLevels( self->opGen, self->numLevels );
MGOpGenerator_Generate( self->opGen, &pOps, &rOps );
for( ii = 1; ii < self->numLevels; ii++ )
PCMGSetInterpolation( pc, ii, pOps[ii] );
Memory_Free( pOps );
Memory_Free( rOps );
}
/* Set the solvers on each level. */
for( ii = 1; ii < self->numLevels; ii++ ) {
KSP smoother;
PC smPc;
PCMGGetSmoother( pc, ii, &smoother );
KSPSetType( smoother, KSPRICHARDSON );
KSPGetPC( smoother, &smPc );
PCSetType( smPc, PCSOR );
KSPSetTolerances( smoother, PETSC_DEFAULT, PETSC_DEFAULT,
PETSC_DEFAULT, 2 );
}
Stg_KSPSetOperators( ksp, sle->kStiffMat->matrix, sle->kStiffMat->matrix,
DIFFERENT_NONZERO_PATTERN );
KSPSetFromOptions( ksp );
/* Because we stole the setup routine we need to do this too. */
if( solver->pcSolver ) {
Journal_DPrintfL( solver->debug, 1,
"Setting up MatrixSolver for the "
"Preconditioner.\n" );
Stg_KSPSetOperators( solver->pcSolver, solver->preconditioner->matrix,
solver->preconditioner->matrix,
DIFFERENT_NONZERO_PATTERN );
KSPSetFromOptions( solver->pcSolver );
}
Stream_UnIndentBranch( StgFEM_Debug );
}
