void PETScMGSolver_UpdateOps( PETScMGSolver* self ) {
PC pc;
Mat *pOps, *rOps;
PetscErrorCode ec;
unsigned l_i;
assert( self && Stg_CheckType( self, PETScMGSolver ) );
ec = KSPGetPC( self->mgData->ksp, &pc );
CheckPETScError( ec );
MGOpGenerator_Generate( self->opGen, (Mat**)&pOps, (Mat**)&rOps );
for( l_i = 1; l_i < self->nLevels; l_i++ ) {
//assert( Stg_CheckType( pOps[l_i], PETScMatrix ) );
//assert( Stg_CheckType( rOps[l_i], PETScMatrix ) );
PETScMGSolver_SetProlongation( self, l_i, pOps[l_i] );
#if( ((PETSC_VERSION_MAJOR==2) && (PETSC_VERSION_MINOR==3) && (PETSC_VERSION_SUBMINOR==3)) || (PETSC_VERSION_MAJOR==3) )
ec = PCMGSetInterpolation( pc, l_i, pOps[l_i] );
#else
ec = PCMGSetInterpolate( pc, l_i, pOps[l_i] );
#endif
CheckPETScError( ec );
PETScMGSolver_SetRestriction( self, l_i, rOps[l_i] );
ec = PCMGSetRestriction( pc, l_i, rOps[l_i] );
CheckPETScError( ec );
}
FreeArray( pOps );
FreeArray( rOps );
}
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);
}
/*@
PCMGGetRestriction - Gets the function to be used to restrict vector
from level l to l-1.
Logically Collective on PC and Mat
Input Parameters:
+ pc - the multigrid context
- l - the level (0 is coarsest) to supply [Do not supply 0]
Output Parameter:
. mat - the restriction matrix
Level: advanced
.keywords: MG, get, multigrid, restriction, level
.seealso: PCMGGetInterpolation(), PCMGSetRestriction(), PCMGGetRScale()
@*/
PetscErrorCode PCMGGetRestriction(PC pc,PetscInt l,Mat *mat)
{
PC_MG *mg = (PC_MG*)pc->data;
PC_MG_Levels **mglevels = mg->levels;
PetscErrorCode ierr;
PetscFunctionBegin;
PetscValidHeaderSpecific(pc,PC_CLASSID,1);
PetscValidPointer(mat,3);
if (!mglevels) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_WRONGSTATE,"Must set MG levels before calling");
if (l <= 0 || mg->nlevels <= l) SETERRQ2(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_OUTOFRANGE,"Level %D must be in range {1,...,%D}",l,mg->nlevels-1);
if (!mglevels[l]->restrct) {
if (!mglevels[l]->interpolate) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_WRONGSTATE,"Must call PCMGSetRestriction() or PCMGSetInterpolation()");
ierr = PCMGSetRestriction(pc,l,mglevels[l]->interpolate);CHKERRQ(ierr);
}
*mat = mglevels[l]->restrct;
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 PCSetUp_MG(PC pc)
{
PC_MG *mg = (PC_MG*)pc->data;
PC_MG_Levels **mglevels = mg->levels;
PetscErrorCode ierr;
PetscInt i,n = mglevels[0]->levels;
PC cpc;
PetscBool dump = PETSC_FALSE,opsset,use_amat,missinginterpolate = PETSC_FALSE;
Mat dA,dB;
Vec tvec;
DM *dms;
PetscViewer viewer = 0;
PetscFunctionBegin;
/* FIX: Move this to PCSetFromOptions_MG? */
if (mg->usedmfornumberoflevels) {
PetscInt levels;
ierr = DMGetRefineLevel(pc->dm,&levels);CHKERRQ(ierr);
levels++;
if (levels > n) { /* the problem is now being solved on a finer grid */
ierr = PCMGSetLevels(pc,levels,NULL);CHKERRQ(ierr);
n = levels;
ierr = PCSetFromOptions(pc);CHKERRQ(ierr); /* it is bad to call this here, but otherwise will never be called for the new hierarchy */
mglevels = mg->levels;
}
}
ierr = KSPGetPC(mglevels[0]->smoothd,&cpc);CHKERRQ(ierr);
/* If user did not provide fine grid operators OR operator was not updated since last global KSPSetOperators() */
/* so use those from global PC */
/* Is this what we always want? What if user wants to keep old one? */
ierr = KSPGetOperatorsSet(mglevels[n-1]->smoothd,NULL,&opsset);CHKERRQ(ierr);
if (opsset) {
Mat mmat;
ierr = KSPGetOperators(mglevels[n-1]->smoothd,NULL,&mmat);CHKERRQ(ierr);
if (mmat == pc->pmat) opsset = PETSC_FALSE;
}
if (!opsset) {
ierr = PCGetUseAmat(pc,&use_amat);CHKERRQ(ierr);
if(use_amat){
ierr = PetscInfo(pc,"Using outer operators to define finest grid operator \n because PCMGGetSmoother(pc,nlevels-1,&ksp);KSPSetOperators(ksp,...); was not called.\n");CHKERRQ(ierr);
ierr = KSPSetOperators(mglevels[n-1]->smoothd,pc->mat,pc->pmat);CHKERRQ(ierr);
}
else {
ierr = PetscInfo(pc,"Using matrix (pmat) operators to define finest grid operator \n because PCMGGetSmoother(pc,nlevels-1,&ksp);KSPSetOperators(ksp,...); was not called.\n");CHKERRQ(ierr);
ierr = KSPSetOperators(mglevels[n-1]->smoothd,pc->pmat,pc->pmat);CHKERRQ(ierr);
}
}
for (i=n-1; i>0; i--) {
if (!(mglevels[i]->interpolate || mglevels[i]->restrct)) {
missinginterpolate = PETSC_TRUE;
continue;
}
}
/*
Skipping if user has provided all interpolation/restriction needed (since DM might not be able to produce them (when coming from SNES/TS)
Skipping for galerkin==2 (externally managed hierarchy such as ML and GAMG). Cleaner logic here would be great. Wrap ML/GAMG as DMs?
*/
if (missinginterpolate && pc->dm && mg->galerkin != 2 && !pc->setupcalled) {
/* construct the interpolation from the DMs */
Mat p;
Vec rscale;
ierr = PetscMalloc1(n,&dms);CHKERRQ(ierr);
dms[n-1] = pc->dm;
/* Separately create them so we do not get DMKSP interference between levels */
for (i=n-2; i>-1; i--) {ierr = DMCoarsen(dms[i+1],MPI_COMM_NULL,&dms[i]);CHKERRQ(ierr);}
for (i=n-2; i>-1; i--) {
DMKSP kdm;
PetscBool dmhasrestrict;
ierr = KSPSetDM(mglevels[i]->smoothd,dms[i]);CHKERRQ(ierr);
if (mg->galerkin) {ierr = KSPSetDMActive(mglevels[i]->smoothd,PETSC_FALSE);CHKERRQ(ierr);}
ierr = DMGetDMKSPWrite(dms[i],&kdm);CHKERRQ(ierr);
/* Ugly hack so that the next KSPSetUp() will use the RHS that we set. A better fix is to change dmActive to take
* a bitwise OR of computing the matrix, RHS, and initial iterate. */
kdm->ops->computerhs = NULL;
kdm->rhsctx = NULL;
if (!mglevels[i+1]->interpolate) {
ierr = DMCreateInterpolation(dms[i],dms[i+1],&p,&rscale);CHKERRQ(ierr);
ierr = PCMGSetInterpolation(pc,i+1,p);CHKERRQ(ierr);
if (rscale) {ierr = PCMGSetRScale(pc,i+1,rscale);CHKERRQ(ierr);}
ierr = VecDestroy(&rscale);CHKERRQ(ierr);
ierr = MatDestroy(&p);CHKERRQ(ierr);
}
ierr = DMHasCreateRestriction(dms[i],&dmhasrestrict);CHKERRQ(ierr);
if (dmhasrestrict && !mglevels[i+1]->restrct){
ierr = DMCreateRestriction(dms[i],dms[i+1],&p);CHKERRQ(ierr);
ierr = PCMGSetRestriction(pc,i+1,p);CHKERRQ(ierr);
ierr = MatDestroy(&p);CHKERRQ(ierr);
}
}
for (i=n-2; i>-1; i--) {ierr = DMDestroy(&dms[i]);CHKERRQ(ierr);}
ierr = PetscFree(dms);CHKERRQ(ierr);
}
if (pc->dm && !pc->setupcalled) {
/* finest smoother also gets DM but it is not active, independent of whether galerkin==2 */
ierr = KSPSetDM(mglevels[n-1]->smoothd,pc->dm);CHKERRQ(ierr);
ierr = KSPSetDMActive(mglevels[n-1]->smoothd,PETSC_FALSE);CHKERRQ(ierr);
}
if (mg->galerkin == 1) {
Mat B;
/* currently only handle case where mat and pmat are the same on coarser levels */
ierr = KSPGetOperators(mglevels[n-1]->smoothd,&dA,&dB);CHKERRQ(ierr);
if (!pc->setupcalled) {
for (i=n-2; i>-1; i--) {
if (!mglevels[i+1]->restrct && !mglevels[i+1]->interpolate) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_WRONGSTATE,"Must provide interpolation or restriction for each MG level except level 0");
if (!mglevels[i+1]->interpolate) {
ierr = PCMGSetInterpolation(pc,i+1,mglevels[i+1]->restrct);CHKERRQ(ierr);
}
if (!mglevels[i+1]->restrct) {
ierr = PCMGSetRestriction(pc,i+1,mglevels[i+1]->interpolate);CHKERRQ(ierr);
}
if (mglevels[i+1]->interpolate == mglevels[i+1]->restrct) {
ierr = MatPtAP(dB,mglevels[i+1]->interpolate,MAT_INITIAL_MATRIX,1.0,&B);CHKERRQ(ierr);
} else {
ierr = MatMatMatMult(mglevels[i+1]->restrct,dB,mglevels[i+1]->interpolate,MAT_INITIAL_MATRIX,1.0,&B);CHKERRQ(ierr);
}
ierr = KSPSetOperators(mglevels[i]->smoothd,B,B);CHKERRQ(ierr);
if (i != n-2) {ierr = PetscObjectDereference((PetscObject)dB);CHKERRQ(ierr);}
dB = B;
}
if (n > 1) {ierr = PetscObjectDereference((PetscObject)dB);CHKERRQ(ierr);}
} else {
for (i=n-2; i>-1; i--) {
if (!mglevels[i+1]->restrct && !mglevels[i+1]->interpolate) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_WRONGSTATE,"Must provide interpolation or restriction for each MG level except level 0");
if (!mglevels[i+1]->interpolate) {
ierr = PCMGSetInterpolation(pc,i+1,mglevels[i+1]->restrct);CHKERRQ(ierr);
}
if (!mglevels[i+1]->restrct) {
ierr = PCMGSetRestriction(pc,i+1,mglevels[i+1]->interpolate);CHKERRQ(ierr);
}
ierr = KSPGetOperators(mglevels[i]->smoothd,NULL,&B);CHKERRQ(ierr);
if (mglevels[i+1]->interpolate == mglevels[i+1]->restrct) {
ierr = MatPtAP(dB,mglevels[i+1]->interpolate,MAT_REUSE_MATRIX,1.0,&B);CHKERRQ(ierr);
} else {
ierr = MatMatMatMult(mglevels[i+1]->restrct,dB,mglevels[i+1]->interpolate,MAT_REUSE_MATRIX,1.0,&B);CHKERRQ(ierr);
}
ierr = KSPSetOperators(mglevels[i]->smoothd,B,B);CHKERRQ(ierr);
dB = B;
}
}
} else if (!mg->galerkin && pc->dm && pc->dm->x) {
/* need to restrict Jacobian location to coarser meshes for evaluation */
for (i=n-2; i>-1; i--) {
Mat R;
Vec rscale;
if (!mglevels[i]->smoothd->dm->x) {
Vec *vecs;
ierr = KSPCreateVecs(mglevels[i]->smoothd,1,&vecs,0,NULL);CHKERRQ(ierr);
mglevels[i]->smoothd->dm->x = vecs[0];
ierr = PetscFree(vecs);CHKERRQ(ierr);
}
ierr = PCMGGetRestriction(pc,i+1,&R);CHKERRQ(ierr);
ierr = PCMGGetRScale(pc,i+1,&rscale);CHKERRQ(ierr);
ierr = MatRestrict(R,mglevels[i+1]->smoothd->dm->x,mglevels[i]->smoothd->dm->x);CHKERRQ(ierr);
ierr = VecPointwiseMult(mglevels[i]->smoothd->dm->x,mglevels[i]->smoothd->dm->x,rscale);CHKERRQ(ierr);
}
}
if (!mg->galerkin && pc->dm) {
for (i=n-2; i>=0; i--) {
DM dmfine,dmcoarse;
Mat Restrict,Inject;
Vec rscale;
ierr = KSPGetDM(mglevels[i+1]->smoothd,&dmfine);CHKERRQ(ierr);
ierr = KSPGetDM(mglevels[i]->smoothd,&dmcoarse);CHKERRQ(ierr);
ierr = PCMGGetRestriction(pc,i+1,&Restrict);CHKERRQ(ierr);
ierr = PCMGGetRScale(pc,i+1,&rscale);CHKERRQ(ierr);
Inject = NULL; /* Callback should create it if it needs Injection */
ierr = DMRestrict(dmfine,Restrict,rscale,Inject,dmcoarse);CHKERRQ(ierr);
}
}
if (!pc->setupcalled) {
for (i=0; i<n; i++) {
ierr = KSPSetFromOptions(mglevels[i]->smoothd);CHKERRQ(ierr);
}
for (i=1; i<n; i++) {
if (mglevels[i]->smoothu && (mglevels[i]->smoothu != mglevels[i]->smoothd)) {
ierr = KSPSetFromOptions(mglevels[i]->smoothu);CHKERRQ(ierr);
}
}
/* insure that if either interpolation or restriction is set the other other one is set */
for (i=1; i<n; i++) {
ierr = PCMGGetInterpolation(pc,i,NULL);CHKERRQ(ierr);
ierr = PCMGGetRestriction(pc,i,NULL);CHKERRQ(ierr);
}
for (i=0; i<n-1; i++) {
if (!mglevels[i]->b) {
Vec *vec;
ierr = KSPCreateVecs(mglevels[i]->smoothd,1,&vec,0,NULL);CHKERRQ(ierr);
ierr = PCMGSetRhs(pc,i,*vec);CHKERRQ(ierr);
ierr = VecDestroy(vec);CHKERRQ(ierr);
ierr = PetscFree(vec);CHKERRQ(ierr);
}
if (!mglevels[i]->r && i) {
ierr = VecDuplicate(mglevels[i]->b,&tvec);CHKERRQ(ierr);
ierr = PCMGSetR(pc,i,tvec);CHKERRQ(ierr);
ierr = VecDestroy(&tvec);CHKERRQ(ierr);
}
if (!mglevels[i]->x) {
ierr = VecDuplicate(mglevels[i]->b,&tvec);CHKERRQ(ierr);
ierr = PCMGSetX(pc,i,tvec);CHKERRQ(ierr);
ierr = VecDestroy(&tvec);CHKERRQ(ierr);
}
}
if (n != 1 && !mglevels[n-1]->r) {
/* PCMGSetR() on the finest level if user did not supply it */
Vec *vec;
ierr = KSPCreateVecs(mglevels[n-1]->smoothd,1,&vec,0,NULL);CHKERRQ(ierr);
ierr = PCMGSetR(pc,n-1,*vec);CHKERRQ(ierr);
ierr = VecDestroy(vec);CHKERRQ(ierr);
ierr = PetscFree(vec);CHKERRQ(ierr);
}
}
if (pc->dm) {
/* need to tell all the coarser levels to rebuild the matrix using the DM for that level */
for (i=0; i<n-1; i++) {
if (mglevels[i]->smoothd->setupstage != KSP_SETUP_NEW) mglevels[i]->smoothd->setupstage = KSP_SETUP_NEWMATRIX;
}
}
for (i=1; i<n; i++) {
if (mglevels[i]->smoothu == mglevels[i]->smoothd || mg->am == PC_MG_FULL || mg->am == PC_MG_KASKADE || mg->cyclesperpcapply > 1){
/* if doing only down then initial guess is zero */
ierr = KSPSetInitialGuessNonzero(mglevels[i]->smoothd,PETSC_TRUE);CHKERRQ(ierr);
}
if (mglevels[i]->eventsmoothsetup) {ierr = PetscLogEventBegin(mglevels[i]->eventsmoothsetup,0,0,0,0);CHKERRQ(ierr);}
ierr = KSPSetUp(mglevels[i]->smoothd);CHKERRQ(ierr);
if (mglevels[i]->smoothd->reason == KSP_DIVERGED_PCSETUP_FAILED) {
pc->failedreason = PC_SUBPC_ERROR;
}
if (mglevels[i]->eventsmoothsetup) {ierr = PetscLogEventEnd(mglevels[i]->eventsmoothsetup,0,0,0,0);CHKERRQ(ierr);}
if (!mglevels[i]->residual) {
Mat mat;
ierr = KSPGetOperators(mglevels[i]->smoothd,NULL,&mat);CHKERRQ(ierr);
ierr = PCMGSetResidual(pc,i,PCMGResidualDefault,mat);CHKERRQ(ierr);
}
}
for (i=1; i<n; i++) {
if (mglevels[i]->smoothu && mglevels[i]->smoothu != mglevels[i]->smoothd) {
Mat downmat,downpmat;
/* check if operators have been set for up, if not use down operators to set them */
ierr = KSPGetOperatorsSet(mglevels[i]->smoothu,&opsset,NULL);CHKERRQ(ierr);
if (!opsset) {
ierr = KSPGetOperators(mglevels[i]->smoothd,&downmat,&downpmat);CHKERRQ(ierr);
ierr = KSPSetOperators(mglevels[i]->smoothu,downmat,downpmat);CHKERRQ(ierr);
}
ierr = KSPSetInitialGuessNonzero(mglevels[i]->smoothu,PETSC_TRUE);CHKERRQ(ierr);
if (mglevels[i]->eventsmoothsetup) {ierr = PetscLogEventBegin(mglevels[i]->eventsmoothsetup,0,0,0,0);CHKERRQ(ierr);}
ierr = KSPSetUp(mglevels[i]->smoothu);CHKERRQ(ierr);
if (mglevels[i]->smoothu->reason == KSP_DIVERGED_PCSETUP_FAILED) {
pc->failedreason = PC_SUBPC_ERROR;
}
if (mglevels[i]->eventsmoothsetup) {ierr = PetscLogEventEnd(mglevels[i]->eventsmoothsetup,0,0,0,0);CHKERRQ(ierr);}
}
}
if (mglevels[0]->eventsmoothsetup) {ierr = PetscLogEventBegin(mglevels[0]->eventsmoothsetup,0,0,0,0);CHKERRQ(ierr);}
ierr = KSPSetUp(mglevels[0]->smoothd);CHKERRQ(ierr);
if (mglevels[0]->smoothd->reason == KSP_DIVERGED_PCSETUP_FAILED) {
pc->failedreason = PC_SUBPC_ERROR;
}
if (mglevels[0]->eventsmoothsetup) {ierr = PetscLogEventEnd(mglevels[0]->eventsmoothsetup,0,0,0,0);CHKERRQ(ierr);}
/*
Dump the interpolation/restriction matrices plus the
Jacobian/stiffness on each level. This allows MATLAB users to
easily check if the Galerkin condition A_c = R A_f R^T is satisfied.
Only support one or the other at the same time.
*/
#if defined(PETSC_USE_SOCKET_VIEWER)
ierr = PetscOptionsGetBool(((PetscObject)pc)->options,((PetscObject)pc)->prefix,"-pc_mg_dump_matlab",&dump,NULL);CHKERRQ(ierr);
if (dump) viewer = PETSC_VIEWER_SOCKET_(PetscObjectComm((PetscObject)pc));
dump = PETSC_FALSE;
#endif
ierr = PetscOptionsGetBool(((PetscObject)pc)->options,((PetscObject)pc)->prefix,"-pc_mg_dump_binary",&dump,NULL);CHKERRQ(ierr);
if (dump) viewer = PETSC_VIEWER_BINARY_(PetscObjectComm((PetscObject)pc));
if (viewer) {
for (i=1; i<n; i++) {
ierr = MatView(mglevels[i]->restrct,viewer);CHKERRQ(ierr);
}
for (i=0; i<n; i++) {
ierr = KSPGetPC(mglevels[i]->smoothd,&pc);CHKERRQ(ierr);
ierr = MatView(pc->mat,viewer);CHKERRQ(ierr);
}
}
PetscFunctionReturn(0);
}
PetscErrorCode PCSetUp_ML(PC pc)
{
PetscErrorCode ierr;
PetscMPIInt size;
FineGridCtx *PetscMLdata;
ML *ml_object;
ML_Aggregate *agg_object;
ML_Operator *mlmat;
PetscInt nlocal_allcols,Nlevels,mllevel,level,level1,m,fine_level,bs;
Mat A,Aloc;
GridCtx *gridctx;
PC_MG *mg = (PC_MG*)pc->data;
PC_ML *pc_ml = (PC_ML*)mg->innerctx;
PetscBool isSeq, isMPI;
KSP smoother;
PC subpc;
PetscInt mesh_level, old_mesh_level;
PetscFunctionBegin;
A = pc->pmat;
ierr = MPI_Comm_size(((PetscObject)A)->comm,&size);CHKERRQ(ierr);
if (pc->setupcalled) {
if (pc->flag == SAME_NONZERO_PATTERN && pc_ml->reuse_interpolation) {
/*
Reuse interpolaton instead of recomputing aggregates and updating the whole hierarchy. This is less expensive for
multiple solves in which the matrix is not changing too quickly.
*/
ml_object = pc_ml->ml_object;
gridctx = pc_ml->gridctx;
Nlevels = pc_ml->Nlevels;
fine_level = Nlevels - 1;
gridctx[fine_level].A = A;
ierr = PetscObjectTypeCompare((PetscObject) A, MATSEQAIJ, &isSeq);CHKERRQ(ierr);
ierr = PetscObjectTypeCompare((PetscObject) A, MATMPIAIJ, &isMPI);CHKERRQ(ierr);
if (isMPI){
ierr = MatConvert_MPIAIJ_ML(A,PETSC_NULL,MAT_INITIAL_MATRIX,&Aloc);CHKERRQ(ierr);
} else if (isSeq) {
Aloc = A;
ierr = PetscObjectReference((PetscObject)Aloc);CHKERRQ(ierr);
} else SETERRQ1(((PetscObject)pc)->comm,PETSC_ERR_ARG_WRONG, "Matrix type '%s' cannot be used with ML. ML can only handle AIJ matrices.",((PetscObject)A)->type_name);
ierr = MatGetSize(Aloc,&m,&nlocal_allcols);CHKERRQ(ierr);
PetscMLdata = pc_ml->PetscMLdata;
ierr = MatDestroy(&PetscMLdata->Aloc);CHKERRQ(ierr);
PetscMLdata->A = A;
PetscMLdata->Aloc = Aloc;
ML_Init_Amatrix(ml_object,0,m,m,PetscMLdata);
ML_Set_Amatrix_Matvec(ml_object,0,PetscML_matvec);
mesh_level = ml_object->ML_finest_level;
while (ml_object->SingleLevel[mesh_level].Rmat->to) {
old_mesh_level = mesh_level;
mesh_level = ml_object->SingleLevel[mesh_level].Rmat->to->levelnum;
/* clean and regenerate A */
mlmat = &(ml_object->Amat[mesh_level]);
ML_Operator_Clean(mlmat);
ML_Operator_Init(mlmat,ml_object->comm);
ML_Gen_AmatrixRAP(ml_object, old_mesh_level, mesh_level);
}
level = fine_level - 1;
if (size == 1) { /* convert ML P, R and A into seqaij format */
for (mllevel=1; mllevel<Nlevels; mllevel++){
mlmat = &(ml_object->Amat[mllevel]);
ierr = MatWrapML_SeqAIJ(mlmat,MAT_REUSE_MATRIX,&gridctx[level].A);CHKERRQ(ierr);
level--;
}
} else { /* convert ML P and R into shell format, ML A into mpiaij format */
for (mllevel=1; mllevel<Nlevels; mllevel++){
mlmat = &(ml_object->Amat[mllevel]);
ierr = MatWrapML_MPIAIJ(mlmat,MAT_REUSE_MATRIX,&gridctx[level].A);CHKERRQ(ierr);
level--;
}
}
for (level=0; level<fine_level; level++) {
if (level > 0){
ierr = PCMGSetResidual(pc,level,PCMGDefaultResidual,gridctx[level].A);CHKERRQ(ierr);
}
ierr = KSPSetOperators(gridctx[level].ksp,gridctx[level].A,gridctx[level].A,SAME_NONZERO_PATTERN);CHKERRQ(ierr);
}
ierr = PCMGSetResidual(pc,fine_level,PCMGDefaultResidual,gridctx[fine_level].A);CHKERRQ(ierr);
ierr = KSPSetOperators(gridctx[fine_level].ksp,gridctx[level].A,gridctx[fine_level].A,SAME_NONZERO_PATTERN);CHKERRQ(ierr);
ierr = PCSetUp_MG(pc);CHKERRQ(ierr);
PetscFunctionReturn(0);
} else {
/* since ML can change the size of vectors/matrices at any level we must destroy everything */
ierr = PCReset_ML(pc);CHKERRQ(ierr);
ierr = PCReset_MG(pc);CHKERRQ(ierr);
}
}
/* setup special features of PCML */
/*--------------------------------*/
/* covert A to Aloc to be used by ML at fine grid */
pc_ml->size = size;
ierr = PetscObjectTypeCompare((PetscObject) A, MATSEQAIJ, &isSeq);CHKERRQ(ierr);
ierr = PetscObjectTypeCompare((PetscObject) A, MATMPIAIJ, &isMPI);CHKERRQ(ierr);
if (isMPI){
ierr = MatConvert_MPIAIJ_ML(A,PETSC_NULL,MAT_INITIAL_MATRIX,&Aloc);CHKERRQ(ierr);
} else if (isSeq) {
Aloc = A;
ierr = PetscObjectReference((PetscObject)Aloc);CHKERRQ(ierr);
} else SETERRQ1(((PetscObject)pc)->comm,PETSC_ERR_ARG_WRONG, "Matrix type '%s' cannot be used with ML. ML can only handle AIJ matrices.",((PetscObject)A)->type_name);
/* create and initialize struct 'PetscMLdata' */
ierr = PetscNewLog(pc,FineGridCtx,&PetscMLdata);CHKERRQ(ierr);
pc_ml->PetscMLdata = PetscMLdata;
ierr = PetscMalloc((Aloc->cmap->n+1)*sizeof(PetscScalar),&PetscMLdata->pwork);CHKERRQ(ierr);
ierr = VecCreate(PETSC_COMM_SELF,&PetscMLdata->x);CHKERRQ(ierr);
ierr = VecSetSizes(PetscMLdata->x,Aloc->cmap->n,Aloc->cmap->n);CHKERRQ(ierr);
ierr = VecSetType(PetscMLdata->x,VECSEQ);CHKERRQ(ierr);
ierr = VecCreate(PETSC_COMM_SELF,&PetscMLdata->y);CHKERRQ(ierr);
ierr = VecSetSizes(PetscMLdata->y,A->rmap->n,PETSC_DECIDE);CHKERRQ(ierr);
ierr = VecSetType(PetscMLdata->y,VECSEQ);CHKERRQ(ierr);
PetscMLdata->A = A;
PetscMLdata->Aloc = Aloc;
/* create ML discretization matrix at fine grid */
/* ML requires input of fine-grid matrix. It determines nlevels. */
ierr = MatGetSize(Aloc,&m,&nlocal_allcols);CHKERRQ(ierr);
ierr = MatGetBlockSize(A,&bs);CHKERRQ(ierr);
ML_Create(&ml_object,pc_ml->MaxNlevels);
ML_Comm_Set_UsrComm(ml_object->comm,((PetscObject)A)->comm);
pc_ml->ml_object = ml_object;
ML_Init_Amatrix(ml_object,0,m,m,PetscMLdata);
ML_Set_Amatrix_Getrow(ml_object,0,PetscML_getrow,PetscML_comm,nlocal_allcols);
ML_Set_Amatrix_Matvec(ml_object,0,PetscML_matvec);
ML_Set_Symmetrize(ml_object,pc_ml->Symmetrize ? ML_YES : ML_NO);
/* aggregation */
ML_Aggregate_Create(&agg_object);
pc_ml->agg_object = agg_object;
{
MatNullSpace mnull;
ierr = MatGetNearNullSpace(A,&mnull);CHKERRQ(ierr);
if (pc_ml->nulltype == PCML_NULLSPACE_AUTO) {
if (mnull) pc_ml->nulltype = PCML_NULLSPACE_USER;
else if (bs > 1) pc_ml->nulltype = PCML_NULLSPACE_BLOCK;
else pc_ml->nulltype = PCML_NULLSPACE_SCALAR;
}
switch (pc_ml->nulltype) {
case PCML_NULLSPACE_USER: {
PetscScalar *nullvec;
const PetscScalar *v;
PetscBool has_const;
PetscInt i,j,mlocal,nvec,M;
const Vec *vecs;
if (!mnull) SETERRQ(((PetscObject)pc)->comm,PETSC_ERR_USER,"Must provide explicit null space using MatSetNearNullSpace() to use user-specified null space");
ierr = MatGetSize(A,&M,PETSC_NULL);CHKERRQ(ierr);
ierr = MatGetLocalSize(Aloc,&mlocal,PETSC_NULL);CHKERRQ(ierr);
ierr = MatNullSpaceGetVecs(mnull,&has_const,&nvec,&vecs);CHKERRQ(ierr);
ierr = PetscMalloc((nvec+!!has_const)*mlocal*sizeof *nullvec,&nullvec);CHKERRQ(ierr);
if (has_const) for (i=0; i<mlocal; i++) nullvec[i] = 1.0/M;
for (i=0; i<nvec; i++) {
ierr = VecGetArrayRead(vecs[i],&v);CHKERRQ(ierr);
for (j=0; j<mlocal; j++) nullvec[(i+!!has_const)*mlocal + j] = v[j];
ierr = VecRestoreArrayRead(vecs[i],&v);CHKERRQ(ierr);
}
ierr = ML_Aggregate_Set_NullSpace(agg_object,bs,nvec+!!has_const,nullvec,mlocal);CHKERRQ(ierr);
ierr = PetscFree(nullvec);CHKERRQ(ierr);
} break;
case PCML_NULLSPACE_BLOCK:
ierr = ML_Aggregate_Set_NullSpace(agg_object,bs,bs,0,0);CHKERRQ(ierr);
break;
case PCML_NULLSPACE_SCALAR:
break;
default: SETERRQ(((PetscObject)pc)->comm,PETSC_ERR_SUP,"Unknown null space type");
}
}
ML_Aggregate_Set_MaxCoarseSize(agg_object,pc_ml->MaxCoarseSize);
/* set options */
switch (pc_ml->CoarsenScheme) {
case 1:
ML_Aggregate_Set_CoarsenScheme_Coupled(agg_object);break;
case 2:
ML_Aggregate_Set_CoarsenScheme_MIS(agg_object);break;
case 3:
ML_Aggregate_Set_CoarsenScheme_METIS(agg_object);break;
}
ML_Aggregate_Set_Threshold(agg_object,pc_ml->Threshold);
ML_Aggregate_Set_DampingFactor(agg_object,pc_ml->DampingFactor);
if (pc_ml->SpectralNormScheme_Anorm){
ML_Set_SpectralNormScheme_Anorm(ml_object);
}
agg_object->keep_agg_information = (int)pc_ml->KeepAggInfo;
agg_object->keep_P_tentative = (int)pc_ml->Reusable;
agg_object->block_scaled_SA = (int)pc_ml->BlockScaling;
agg_object->minimizing_energy = (int)pc_ml->EnergyMinimization;
agg_object->minimizing_energy_droptol = (double)pc_ml->EnergyMinimizationDropTol;
agg_object->cheap_minimizing_energy = (int)pc_ml->EnergyMinimizationCheap;
if (pc_ml->OldHierarchy) {
Nlevels = ML_Gen_MGHierarchy_UsingAggregation(ml_object,0,ML_INCREASING,agg_object);
} else {
Nlevels = ML_Gen_MultiLevelHierarchy_UsingAggregation(ml_object,0,ML_INCREASING,agg_object);
}
if (Nlevels<=0) SETERRQ1(((PetscObject)pc)->comm,PETSC_ERR_ARG_OUTOFRANGE,"Nlevels %d must > 0",Nlevels);
pc_ml->Nlevels = Nlevels;
fine_level = Nlevels - 1;
ierr = PCMGSetLevels(pc,Nlevels,PETSC_NULL);CHKERRQ(ierr);
/* set default smoothers */
for (level=1; level<=fine_level; level++){
if (size == 1){
ierr = PCMGGetSmoother(pc,level,&smoother);CHKERRQ(ierr);
ierr = KSPSetType(smoother,KSPRICHARDSON);CHKERRQ(ierr);
ierr = KSPGetPC(smoother,&subpc);CHKERRQ(ierr);
ierr = PCSetType(subpc,PCSOR);CHKERRQ(ierr);
} else {
ierr = PCMGGetSmoother(pc,level,&smoother);CHKERRQ(ierr);
ierr = KSPSetType(smoother,KSPRICHARDSON);CHKERRQ(ierr);
ierr = KSPGetPC(smoother,&subpc);CHKERRQ(ierr);
ierr = PCSetType(subpc,PCSOR);CHKERRQ(ierr);
}
}
ierr = PetscObjectOptionsBegin((PetscObject)pc);CHKERRQ(ierr);
ierr = PCSetFromOptions_MG(pc);CHKERRQ(ierr); /* should be called in PCSetFromOptions_ML(), but cannot be called prior to PCMGSetLevels() */
ierr = PetscOptionsEnd();CHKERRQ(ierr);
ierr = PetscMalloc(Nlevels*sizeof(GridCtx),&gridctx);CHKERRQ(ierr);
pc_ml->gridctx = gridctx;
/* wrap ML matrices by PETSc shell matrices at coarsened grids.
Level 0 is the finest grid for ML, but coarsest for PETSc! */
gridctx[fine_level].A = A;
level = fine_level - 1;
if (size == 1){ /* convert ML P, R and A into seqaij format */
for (mllevel=1; mllevel<Nlevels; mllevel++){
mlmat = &(ml_object->Pmat[mllevel]);
ierr = MatWrapML_SeqAIJ(mlmat,MAT_INITIAL_MATRIX,&gridctx[level].P);CHKERRQ(ierr);
mlmat = &(ml_object->Rmat[mllevel-1]);
ierr = MatWrapML_SeqAIJ(mlmat,MAT_INITIAL_MATRIX,&gridctx[level].R);CHKERRQ(ierr);
mlmat = &(ml_object->Amat[mllevel]);
ierr = MatWrapML_SeqAIJ(mlmat,MAT_INITIAL_MATRIX,&gridctx[level].A);CHKERRQ(ierr);
level--;
}
} else { /* convert ML P and R into shell format, ML A into mpiaij format */
for (mllevel=1; mllevel<Nlevels; mllevel++){
mlmat = &(ml_object->Pmat[mllevel]);
ierr = MatWrapML_SHELL(mlmat,MAT_INITIAL_MATRIX,&gridctx[level].P);CHKERRQ(ierr);
mlmat = &(ml_object->Rmat[mllevel-1]);
ierr = MatWrapML_SHELL(mlmat,MAT_INITIAL_MATRIX,&gridctx[level].R);CHKERRQ(ierr);
mlmat = &(ml_object->Amat[mllevel]);
ierr = MatWrapML_MPIAIJ(mlmat,MAT_INITIAL_MATRIX,&gridctx[level].A);CHKERRQ(ierr);
level--;
}
}
/* create vectors and ksp at all levels */
for (level=0; level<fine_level; level++){
level1 = level + 1;
ierr = VecCreate(((PetscObject)gridctx[level].A)->comm,&gridctx[level].x);CHKERRQ(ierr);
ierr = VecSetSizes(gridctx[level].x,gridctx[level].A->cmap->n,PETSC_DECIDE);CHKERRQ(ierr);
ierr = VecSetType(gridctx[level].x,VECMPI);CHKERRQ(ierr);
ierr = PCMGSetX(pc,level,gridctx[level].x);CHKERRQ(ierr);
ierr = VecCreate(((PetscObject)gridctx[level].A)->comm,&gridctx[level].b);CHKERRQ(ierr);
ierr = VecSetSizes(gridctx[level].b,gridctx[level].A->rmap->n,PETSC_DECIDE);CHKERRQ(ierr);
ierr = VecSetType(gridctx[level].b,VECMPI);CHKERRQ(ierr);
ierr = PCMGSetRhs(pc,level,gridctx[level].b);CHKERRQ(ierr);
ierr = VecCreate(((PetscObject)gridctx[level1].A)->comm,&gridctx[level1].r);CHKERRQ(ierr);
ierr = VecSetSizes(gridctx[level1].r,gridctx[level1].A->rmap->n,PETSC_DECIDE);CHKERRQ(ierr);
ierr = VecSetType(gridctx[level1].r,VECMPI);CHKERRQ(ierr);
ierr = PCMGSetR(pc,level1,gridctx[level1].r);CHKERRQ(ierr);
if (level == 0){
ierr = PCMGGetCoarseSolve(pc,&gridctx[level].ksp);CHKERRQ(ierr);
} else {
ierr = PCMGGetSmoother(pc,level,&gridctx[level].ksp);CHKERRQ(ierr);
}
}
ierr = PCMGGetSmoother(pc,fine_level,&gridctx[fine_level].ksp);CHKERRQ(ierr);
/* create coarse level and the interpolation between the levels */
for (level=0; level<fine_level; level++){
level1 = level + 1;
ierr = PCMGSetInterpolation(pc,level1,gridctx[level].P);CHKERRQ(ierr);
ierr = PCMGSetRestriction(pc,level1,gridctx[level].R);CHKERRQ(ierr);
if (level > 0){
ierr = PCMGSetResidual(pc,level,PCMGDefaultResidual,gridctx[level].A);CHKERRQ(ierr);
}
ierr = KSPSetOperators(gridctx[level].ksp,gridctx[level].A,gridctx[level].A,DIFFERENT_NONZERO_PATTERN);CHKERRQ(ierr);
}
ierr = PCMGSetResidual(pc,fine_level,PCMGDefaultResidual,gridctx[fine_level].A);CHKERRQ(ierr);
ierr = KSPSetOperators(gridctx[fine_level].ksp,gridctx[level].A,gridctx[fine_level].A,DIFFERENT_NONZERO_PATTERN);CHKERRQ(ierr);
/* setupcalled is set to 0 so that MG is setup from scratch */
pc->setupcalled = 0;
ierr = PCSetUp_MG(pc);CHKERRQ(ierr);
PetscFunctionReturn(0);
}
PETSC_EXTERN void PETSC_STDCALL pcmgsetrestriction_(PC pc,PetscInt *l,Mat mat, int *__ierr ){
*__ierr = PCMGSetRestriction(
(PC)PetscToPointer((pc) ),*l,
(Mat)PetscToPointer((mat) ));
}
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;
}