PetscErrorCode KSPSetFromOptions_Chebyshev(KSP ksp)
{
KSP_Chebyshev *cheb = (KSP_Chebyshev*)ksp->data;
PetscErrorCode ierr;
PetscInt two = 2,four = 4;
PetscReal tform[4] = {PETSC_DECIDE,PETSC_DECIDE,PETSC_DECIDE,PETSC_DECIDE};
PetscBool flg;
PetscFunctionBegin;
ierr = PetscOptionsHead("KSP Chebyshev Options");CHKERRQ(ierr);
ierr = PetscOptionsInt("-ksp_chebyshev_eststeps","Number of est steps in Chebyshev","",cheb->eststeps,&cheb->eststeps,NULL);CHKERRQ(ierr);
ierr = PetscOptionsRealArray("-ksp_chebyshev_eigenvalues","extreme eigenvalues","KSPChebyshevSetEigenvalues",&cheb->emin,&two,0);CHKERRQ(ierr);
ierr = PetscOptionsRealArray("-ksp_chebyshev_estimate_eigenvalues","estimate eigenvalues using a Krylov method, then use this transform for Chebyshev eigenvalue bounds","KSPChebyshevSetEstimateEigenvalues",tform,&four,&flg);CHKERRQ(ierr);
if (flg) {
switch (four) {
case 0:
ierr = KSPChebyshevSetEstimateEigenvalues(ksp,PETSC_DECIDE,PETSC_DECIDE,PETSC_DECIDE,PETSC_DECIDE);CHKERRQ(ierr);
break;
case 2: /* Base everything on the max eigenvalues */
ierr = KSPChebyshevSetEstimateEigenvalues(ksp,PETSC_DECIDE,tform[0],PETSC_DECIDE,tform[1]);CHKERRQ(ierr);
break;
case 4: /* Use the full 2x2 linear transformation */
ierr = KSPChebyshevSetEstimateEigenvalues(ksp,tform[0],tform[1],tform[2],tform[3]);CHKERRQ(ierr);
break;
default: SETERRQ(PetscObjectComm((PetscObject)ksp),PETSC_ERR_ARG_INCOMP,"Must specify either 0, 2, or 4 parameters for eigenvalue estimation");
}
}
if (cheb->kspest) {
PetscBool estrand = PETSC_FALSE;
ierr = PetscOptionsBool("-ksp_chebyshev_estimate_eigenvalues_random","Use Random right hand side for eigenvalue estimation","KSPChebyshevEstEigSetRandom",estrand,&estrand,NULL);CHKERRQ(ierr);
if (estrand) {
PetscRandom random;
ierr = PetscRandomCreate(PetscObjectComm((PetscObject)ksp),&random);CHKERRQ(ierr);
ierr = PetscObjectSetOptionsPrefix((PetscObject)random,((PetscObject)ksp)->prefix);CHKERRQ(ierr);
ierr = PetscObjectAppendOptionsPrefix((PetscObject)random,"ksp_chebyshev_estimate_eigenvalues_");CHKERRQ(ierr);
ierr = PetscRandomSetFromOptions(random);CHKERRQ(ierr);
ierr = KSPChebyshevEstEigSetRandom(ksp,random);CHKERRQ(ierr);
ierr = PetscRandomDestroy(&random);CHKERRQ(ierr);
}
}
if (cheb->kspest) {
/* Mask the PC so that PCSetFromOptions does not do anything */
ierr = KSPSetPC(cheb->kspest,cheb->pcnone);CHKERRQ(ierr);
ierr = KSPSetOptionsPrefix(cheb->kspest,((PetscObject)ksp)->prefix);CHKERRQ(ierr);
ierr = KSPAppendOptionsPrefix(cheb->kspest,"est_");CHKERRQ(ierr);
if (!((PetscObject)cheb->kspest)->type_name) {
ierr = KSPSetType(cheb->kspest,KSPGMRES);CHKERRQ(ierr);
}
ierr = KSPSetFromOptions(cheb->kspest);CHKERRQ(ierr);
ierr = KSPSetPC(cheb->kspest,ksp->pc);CHKERRQ(ierr);
}
ierr = PetscOptionsTail();CHKERRQ(ierr);
PetscFunctionReturn(0);
}
static PetscErrorCode KSPChebyshevEstEigSet_Chebyshev(KSP ksp,PetscReal a,PetscReal b,PetscReal c,PetscReal d)
{
KSP_Chebyshev *cheb = (KSP_Chebyshev*)ksp->data;
PetscErrorCode ierr;
PetscFunctionBegin;
if (a != 0.0 || b != 0.0 || c != 0.0 || d != 0.0) {
if (!cheb->kspest) { /* should this block of code be moved to KSPSetUp_Chebyshev()? */
ierr = KSPCreate(PetscObjectComm((PetscObject)ksp),&cheb->kspest);CHKERRQ(ierr);
ierr = PetscObjectIncrementTabLevel((PetscObject)cheb->kspest,(PetscObject)ksp,1);CHKERRQ(ierr);
ierr = KSPSetOptionsPrefix(cheb->kspest,((PetscObject)ksp)->prefix);CHKERRQ(ierr);
ierr = KSPAppendOptionsPrefix(cheb->kspest,"esteig_");CHKERRQ(ierr);
ierr = KSPSetSkipPCSetFromOptions(cheb->kspest,PETSC_TRUE);CHKERRQ(ierr);
ierr = KSPSetPC(cheb->kspest,ksp->pc);CHKERRQ(ierr);
ierr = KSPSetComputeEigenvalues(cheb->kspest,PETSC_TRUE);CHKERRQ(ierr);
/* We cannot turn off convergence testing because GMRES will break down if you attempt to keep iterating after a zero norm is obtained */
ierr = KSPSetTolerances(cheb->kspest,1.e-12,PETSC_DEFAULT,PETSC_DEFAULT,cheb->eststeps);CHKERRQ(ierr);
}
if (a >= 0) cheb->tform[0] = a;
if (b >= 0) cheb->tform[1] = b;
if (c >= 0) cheb->tform[2] = c;
if (d >= 0) cheb->tform[3] = d;
cheb->amatid = 0;
cheb->pmatid = 0;
cheb->amatstate = -1;
cheb->pmatstate = -1;
} else {
ierr = KSPDestroy(&cheb->kspest);CHKERRQ(ierr);
}
PetscFunctionReturn(0);
}
static PetscErrorCode KSPComputeShifts_GMRES(KSP ksp)
{
PetscErrorCode ierr;
KSP_AGMRES *agmres = (KSP_AGMRES*)(ksp->data);
KSP kspgmres;
Mat Amat, Pmat;
MatStructure flag;
PetscInt max_k = agmres->max_k;
PC pc;
PetscInt m;
PetscScalar *Rshift, *Ishift;
PetscFunctionBegin;
/* Perform one cycle of classical GMRES (with the Arnoldi process) to get the Hessenberg matrix
We assume here that the ksp is AGMRES and that the operators for the
linear system have been set in this ksp */
ierr = KSPCreate(PetscObjectComm((PetscObject)ksp), &kspgmres);CHKERRQ(ierr);
if (!ksp->pc) { ierr = KSPGetPC(ksp,&ksp->pc);CHKERRQ(ierr); }
ierr = PCGetOperators(ksp->pc, &Amat, &Pmat);CHKERRQ(ierr);
ierr = KSPSetOperators(kspgmres, Amat, Pmat);CHKERRQ(ierr);
ierr = KSPSetFromOptions(kspgmres);CHKERRQ(ierr);
ierr = PetscOptionsHasName(NULL, "-ksp_view", &flg);CHKERRQ(ierr);
if (flag) { ierr = PetscOptionsClearValue("-ksp_view");CHKERRQ(ierr); }
ierr = KSPSetType(kspgmres, KSPGMRES);CHKERRQ(ierr);
ierr = KSPGMRESSetRestart(kspgmres, max_k);CHKERRQ(ierr);
ierr = KSPGetPC(ksp, &pc);CHKERRQ(ierr);
ierr = KSPSetPC(kspgmres, pc);CHKERRQ(ierr);
/* Copy common options */
kspgmres->pc_side = ksp->pc_side;
/* Setup KSP context */
ierr = KSPSetComputeEigenvalues(kspgmres, PETSC_TRUE);CHKERRQ(ierr);
ierr = KSPSetUp(kspgmres);CHKERRQ(ierr);
kspgmres->max_it = max_k; /* Restrict the maximum number of iterations to one cycle of GMRES */
kspgmres->rtol = ksp->rtol;
ierr = KSPSolve(kspgmres, ksp->vec_rhs, ksp->vec_sol);CHKERRQ(ierr);
ksp->guess_zero = PETSC_FALSE;
ksp->rnorm = kspgmres->rnorm;
ksp->its = kspgmres->its;
if (kspgmres->reason == KSP_CONVERGED_RTOL) {
ksp->reason = KSP_CONVERGED_RTOL;
PetscFunctionReturn(0);
} else ksp->reason = KSP_CONVERGED_ITERATING;
/* Now, compute the Shifts values */
ierr = PetscMalloc2(max_k,&Rshift,max_k,&Ishift);CHKERRQ(ierr);
ierr = KSPComputeEigenvalues(kspgmres, max_k, Rshift, Ishift, &m);CHKERRQ(ierr);
if (m < max_k) SETERRQ(PetscObjectComm((PetscObject)ksp),PETSC_ERR_PLIB, "Unable to compute the Shifts for the Newton basis");
else {
ierr = KSPAGMRESLejaOrdering(Rshift, Ishift, agmres->Rshift, agmres->Ishift, max_k);CHKERRQ(ierr);
agmres->HasShifts = PETSC_TRUE;
}
/* Restore KSP view options */
if (flg) { ierr = PetscOptionsSetValue("-ksp_view", "");CHKERRQ(ierr); }
PetscFunctionReturn(0);
}
static PetscErrorCode KSPSetUp_SpecEst(KSP ksp)
{
KSP_SpecEst *spec = (KSP_SpecEst*)ksp->data;
PetscErrorCode ierr;
PetscBool nonzero;
PetscFunctionBegin;
ierr = KSPSetPC(spec->kspest,ksp->pc);CHKERRQ(ierr);
ierr = KSPSetPC(spec->kspcheap,ksp->pc);CHKERRQ(ierr);
ierr = KSPGetInitialGuessNonzero(ksp,&nonzero);CHKERRQ(ierr);
ierr = KSPSetInitialGuessNonzero(spec->kspest,nonzero);CHKERRQ(ierr);
ierr = KSPSetInitialGuessNonzero(spec->kspcheap,nonzero);CHKERRQ(ierr);
ierr = KSPSetComputeSingularValues(spec->kspest,PETSC_TRUE);CHKERRQ(ierr);
ierr = KSPSetUp(spec->kspest);CHKERRQ(ierr);
spec->current = PETSC_FALSE;
PetscFunctionReturn(0);
}
void createOuterKsp(OuterContext* ctx) {
KSPCreate((ctx->data)->commAll, &(ctx->outerKsp));
PetscObjectIncrementTabLevel((PetscObject)(ctx->outerKsp), PETSC_NULL, 0);
KSPSetType(ctx->outerKsp, KSPFGMRES);
KSPSetTolerances(ctx->outerKsp, 1.0e-12, 1.0e-12, PETSC_DEFAULT, 50);
KSPSetPC(ctx->outerKsp, ctx->outerPC);
KSPSetOptionsPrefix(ctx->outerKsp, "outer_");
KSPSetFromOptions(ctx->outerKsp);
KSPSetOperators(ctx->outerKsp, ctx->outerMat,
ctx->outerMat, SAME_NONZERO_PATTERN);
KSPSetUp(ctx->outerKsp);
}
static PetscErrorCode KSPSetFromOptions_SpecEst(KSP ksp)
{
PetscErrorCode ierr;
KSP_SpecEst *spec = (KSP_SpecEst*)ksp->data;
char prefix[256];
PetscFunctionBegin;
ierr = PetscOptionsHead("KSP SpecEst Options");CHKERRQ(ierr);
ierr = PetscOptionsReal("-ksp_specest_minfactor","Multiplier on the minimum eigen/singular value","None",spec->minfactor,&spec->minfactor,PETSC_NULL);CHKERRQ(ierr);
ierr = PetscOptionsReal("-ksp_specest_maxfactor","Multiplier on the maximum eigen/singular value","None",spec->maxfactor,&spec->maxfactor,PETSC_NULL);CHKERRQ(ierr);
ierr = PetscOptionsReal("-ksp_specest_richfactor","Multiplier on the richimum eigen/singular value","None",spec->richfactor,&spec->richfactor,PETSC_NULL);CHKERRQ(ierr);
ierr = PetscOptionsTail();CHKERRQ(ierr);
/* Mask the PC so that PCSetFromOptions does not do anything */
ierr = KSPSetPC(spec->kspest,spec->pcnone);CHKERRQ(ierr);
ierr = KSPSetPC(spec->kspcheap,spec->pcnone);CHKERRQ(ierr);
ierr = PetscSNPrintf(prefix,sizeof prefix,"%sspecest_",((PetscObject)ksp)->prefix?((PetscObject)ksp)->prefix:"");CHKERRQ(ierr);
ierr = KSPSetOptionsPrefix(spec->kspest,prefix);CHKERRQ(ierr);
ierr = PetscSNPrintf(prefix,sizeof prefix,"%sspeccheap_",((PetscObject)ksp)->prefix?((PetscObject)ksp)->prefix:"");CHKERRQ(ierr);
ierr = KSPSetOptionsPrefix(spec->kspcheap,prefix);CHKERRQ(ierr);
if (!((PetscObject)spec->kspest)->type_name) {
ierr = KSPSetType(spec->kspest,KSPGMRES);CHKERRQ(ierr);
}
if (!((PetscObject)spec->kspcheap)->type_name) {
ierr = KSPSetType(spec->kspcheap,KSPCHEBYSHEV);CHKERRQ(ierr);
}
ierr = KSPSetFromOptions(spec->kspest);CHKERRQ(ierr);
ierr = KSPSetFromOptions(spec->kspcheap);CHKERRQ(ierr);
/* Unmask the PC */
ierr = KSPSetPC(spec->kspest,ksp->pc);CHKERRQ(ierr);
ierr = KSPSetPC(spec->kspcheap,ksp->pc);CHKERRQ(ierr);
PetscFunctionReturn(0);
}
static PetscErrorCode KSPChebyshevSetEstimateEigenvalues_Chebyshev(KSP ksp,PetscReal a,PetscReal b,PetscReal c,PetscReal d)
{
KSP_Chebyshev *cheb = (KSP_Chebyshev*)ksp->data;
PetscErrorCode ierr;
PetscFunctionBegin;
if (a != 0.0 || b != 0.0 || c != 0.0 || d != 0.0) {
if (!cheb->kspest) { /* should this block of code be moved to KSPSetUp_Chebyshev()? */
PetscBool nonzero;
ierr = KSPCreate(PetscObjectComm((PetscObject)ksp),&cheb->kspest);CHKERRQ(ierr);
ierr = PetscObjectIncrementTabLevel((PetscObject)cheb->kspest,(PetscObject)ksp,1);CHKERRQ(ierr);
ierr = KSPSetOptionsPrefix(cheb->kspest,((PetscObject)ksp)->prefix);CHKERRQ(ierr);
ierr = KSPAppendOptionsPrefix(cheb->kspest,"est_");CHKERRQ(ierr);
ierr = KSPGetPC(cheb->kspest,&cheb->pcnone);CHKERRQ(ierr);
ierr = PetscObjectReference((PetscObject)cheb->pcnone);CHKERRQ(ierr);
ierr = PCSetType(cheb->pcnone,PCNONE);CHKERRQ(ierr);
ierr = KSPSetPC(cheb->kspest,ksp->pc);CHKERRQ(ierr);
ierr = KSPGetInitialGuessNonzero(ksp,&nonzero);CHKERRQ(ierr);
ierr = KSPSetInitialGuessNonzero(cheb->kspest,nonzero);CHKERRQ(ierr);
ierr = KSPSetComputeEigenvalues(cheb->kspest,PETSC_TRUE);CHKERRQ(ierr);
/* Estimate with a fixed number of iterations */
ierr = KSPSetConvergenceTest(cheb->kspest,KSPConvergedSkip,0,0);CHKERRQ(ierr);
ierr = KSPSetNormType(cheb->kspest,KSP_NORM_NONE);CHKERRQ(ierr);
ierr = KSPSetTolerances(cheb->kspest,PETSC_DEFAULT,PETSC_DEFAULT,PETSC_DEFAULT,cheb->eststeps);CHKERRQ(ierr);
}
if (a >= 0) cheb->tform[0] = a;
if (b >= 0) cheb->tform[1] = b;
if (c >= 0) cheb->tform[2] = c;
if (d >= 0) cheb->tform[3] = d;
cheb->estimate_current = PETSC_FALSE;
} else {
ierr = KSPDestroy(&cheb->kspest);CHKERRQ(ierr);
ierr = PCDestroy(&cheb->pcnone);CHKERRQ(ierr);
}
PetscFunctionReturn(0);
}
static PetscErrorCode ComputeKSPFETIDP(DomainData dd, KSP ksp_bddc, KSP *ksp_fetidp)
{
PetscErrorCode ierr;
KSP temp_ksp;
PC pc,D;
Mat F;
PetscFunctionBeginUser;
ierr = KSPGetPC(ksp_bddc,&pc);CHKERRQ(ierr);
ierr = PCBDDCCreateFETIDPOperators(pc,&F,&D);CHKERRQ(ierr);
ierr = KSPCreate(PetscObjectComm((PetscObject)F),&temp_ksp);CHKERRQ(ierr);
ierr = KSPSetOperators(temp_ksp,F,F);CHKERRQ(ierr);
ierr = KSPSetType(temp_ksp,KSPCG);CHKERRQ(ierr);
ierr = KSPSetPC(temp_ksp,D);CHKERRQ(ierr);
ierr = KSPSetComputeSingularValues(temp_ksp,PETSC_TRUE);CHKERRQ(ierr);
ierr = KSPSetFromOptions(temp_ksp);CHKERRQ(ierr);
ierr = KSPSetUp(temp_ksp);CHKERRQ(ierr);
*ksp_fetidp = temp_ksp;
ierr = MatDestroy(&F);CHKERRQ(ierr);
ierr = PCDestroy(&D);CHKERRQ(ierr);
PetscFunctionReturn(0);
}
PetscErrorCode PCBDDCNullSpaceAssembleCorrection(PC pc, PetscBool isdir, IS local_dofs)
{
PC_BDDC *pcbddc = (PC_BDDC*)pc->data;
PC_IS *pcis = (PC_IS*)pc->data;
Mat_IS* matis = (Mat_IS*)pc->pmat->data;
KSP local_ksp;
PC newpc;
NullSpaceCorrection_ctx shell_ctx;
Mat local_mat,local_pmat,small_mat,inv_small_mat;
Vec work1,work2;
const Vec *nullvecs;
VecScatter scatter_ctx;
IS is_aux;
MatFactorInfo matinfo;
PetscScalar *basis_mat,*Kbasis_mat,*array,*array_mat;
PetscScalar one = 1.0,zero = 0.0, m_one = -1.0;
PetscInt basis_dofs,basis_size,nnsp_size,i,k;
PetscBool nnsp_has_cnst;
PetscErrorCode ierr;
PetscFunctionBegin;
/* Infer the local solver */
ierr = ISGetSize(local_dofs,&basis_dofs);CHKERRQ(ierr);
if (isdir) {
/* Dirichlet solver */
local_ksp = pcbddc->ksp_D;
} else {
/* Neumann solver */
local_ksp = pcbddc->ksp_R;
}
ierr = KSPGetOperators(local_ksp,&local_mat,&local_pmat);CHKERRQ(ierr);
/* Get null space vecs */
ierr = MatNullSpaceGetVecs(pcbddc->NullSpace,&nnsp_has_cnst,&nnsp_size,&nullvecs);CHKERRQ(ierr);
basis_size = nnsp_size;
if (nnsp_has_cnst) {
basis_size++;
}
if (basis_dofs) {
/* Create shell ctx */
ierr = PetscNew(&shell_ctx);CHKERRQ(ierr);
/* Create work vectors in shell context */
ierr = VecCreate(PETSC_COMM_SELF,&shell_ctx->work_small_1);CHKERRQ(ierr);
ierr = VecSetSizes(shell_ctx->work_small_1,basis_size,basis_size);CHKERRQ(ierr);
ierr = VecSetType(shell_ctx->work_small_1,VECSEQ);CHKERRQ(ierr);
ierr = VecDuplicate(shell_ctx->work_small_1,&shell_ctx->work_small_2);CHKERRQ(ierr);
ierr = VecCreate(PETSC_COMM_SELF,&shell_ctx->work_full_1);CHKERRQ(ierr);
ierr = VecSetSizes(shell_ctx->work_full_1,basis_dofs,basis_dofs);CHKERRQ(ierr);
ierr = VecSetType(shell_ctx->work_full_1,VECSEQ);CHKERRQ(ierr);
ierr = VecDuplicate(shell_ctx->work_full_1,&shell_ctx->work_full_2);CHKERRQ(ierr);
/* Allocate workspace */
ierr = MatCreateSeqDense(PETSC_COMM_SELF,basis_dofs,basis_size,NULL,&shell_ctx->basis_mat );CHKERRQ(ierr);
ierr = MatCreateSeqDense(PETSC_COMM_SELF,basis_dofs,basis_size,NULL,&shell_ctx->Kbasis_mat);CHKERRQ(ierr);
ierr = MatDenseGetArray(shell_ctx->basis_mat,&basis_mat);CHKERRQ(ierr);
ierr = MatDenseGetArray(shell_ctx->Kbasis_mat,&Kbasis_mat);CHKERRQ(ierr);
/* Restrict local null space on selected dofs (Dirichlet or Neumann)
and compute matrices N and K*N */
ierr = VecDuplicate(shell_ctx->work_full_1,&work1);CHKERRQ(ierr);
ierr = VecDuplicate(shell_ctx->work_full_1,&work2);CHKERRQ(ierr);
ierr = VecScatterCreate(pcis->vec1_N,local_dofs,work1,(IS)0,&scatter_ctx);CHKERRQ(ierr);
}
for (k=0;k<nnsp_size;k++) {
ierr = VecScatterBegin(matis->rctx,nullvecs[k],pcis->vec1_N,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
ierr = VecScatterEnd(matis->rctx,nullvecs[k],pcis->vec1_N,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
if (basis_dofs) {
ierr = VecPlaceArray(work1,(const PetscScalar*)&basis_mat[k*basis_dofs]);CHKERRQ(ierr);
ierr = VecScatterBegin(scatter_ctx,pcis->vec1_N,work1,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
ierr = VecScatterEnd(scatter_ctx,pcis->vec1_N,work1,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
ierr = VecPlaceArray(work2,(const PetscScalar*)&Kbasis_mat[k*basis_dofs]);CHKERRQ(ierr);
ierr = MatMult(local_mat,work1,work2);CHKERRQ(ierr);
ierr = VecResetArray(work1);CHKERRQ(ierr);
ierr = VecResetArray(work2);CHKERRQ(ierr);
}
}
if (basis_dofs) {
if (nnsp_has_cnst) {
ierr = VecPlaceArray(work1,(const PetscScalar*)&basis_mat[k*basis_dofs]);CHKERRQ(ierr);
ierr = VecSet(work1,one);CHKERRQ(ierr);
ierr = VecPlaceArray(work2,(const PetscScalar*)&Kbasis_mat[k*basis_dofs]);CHKERRQ(ierr);
ierr = MatMult(local_mat,work1,work2);CHKERRQ(ierr);
ierr = VecResetArray(work1);CHKERRQ(ierr);
ierr = VecResetArray(work2);CHKERRQ(ierr);
}
ierr = VecDestroy(&work1);CHKERRQ(ierr);
ierr = VecDestroy(&work2);CHKERRQ(ierr);
ierr = VecScatterDestroy(&scatter_ctx);CHKERRQ(ierr);
ierr = MatDenseRestoreArray(shell_ctx->basis_mat,&basis_mat);CHKERRQ(ierr);
ierr = MatDenseRestoreArray(shell_ctx->Kbasis_mat,&Kbasis_mat);CHKERRQ(ierr);
/* Assemble another Mat object in shell context */
ierr = MatTransposeMatMult(shell_ctx->basis_mat,shell_ctx->Kbasis_mat,MAT_INITIAL_MATRIX,PETSC_DEFAULT,&small_mat);CHKERRQ(ierr);
ierr = MatFactorInfoInitialize(&matinfo);CHKERRQ(ierr);
ierr = ISCreateStride(PETSC_COMM_SELF,basis_size,0,1,&is_aux);CHKERRQ(ierr);
ierr = MatLUFactor(small_mat,is_aux,is_aux,&matinfo);CHKERRQ(ierr);
ierr = ISDestroy(&is_aux);CHKERRQ(ierr);
ierr = PetscMalloc1(basis_size*basis_size,&array_mat);CHKERRQ(ierr);
for (k=0;k<basis_size;k++) {
ierr = VecSet(shell_ctx->work_small_1,zero);CHKERRQ(ierr);
ierr = VecSetValue(shell_ctx->work_small_1,k,one,INSERT_VALUES);CHKERRQ(ierr);
ierr = VecAssemblyBegin(shell_ctx->work_small_1);CHKERRQ(ierr);
ierr = VecAssemblyEnd(shell_ctx->work_small_1);CHKERRQ(ierr);
ierr = MatSolve(small_mat,shell_ctx->work_small_1,shell_ctx->work_small_2);CHKERRQ(ierr);
ierr = VecGetArrayRead(shell_ctx->work_small_2,(const PetscScalar**)&array);CHKERRQ(ierr);
for (i=0;i<basis_size;i++) {
array_mat[i*basis_size+k]=array[i];
}
ierr = VecRestoreArrayRead(shell_ctx->work_small_2,(const PetscScalar**)&array);CHKERRQ(ierr);
}
ierr = MatCreateSeqDense(PETSC_COMM_SELF,basis_size,basis_size,array_mat,&inv_small_mat);CHKERRQ(ierr);
ierr = MatMatMult(shell_ctx->basis_mat,inv_small_mat,MAT_INITIAL_MATRIX,PETSC_DEFAULT,&shell_ctx->Lbasis_mat);CHKERRQ(ierr);
ierr = PetscFree(array_mat);CHKERRQ(ierr);
ierr = MatDestroy(&inv_small_mat);CHKERRQ(ierr);
ierr = MatDestroy(&small_mat);CHKERRQ(ierr);
ierr = MatScale(shell_ctx->Kbasis_mat,m_one);CHKERRQ(ierr);
/* Rebuild local PC */
ierr = KSPGetPC(local_ksp,&shell_ctx->local_pc);CHKERRQ(ierr);
ierr = PetscObjectReference((PetscObject)shell_ctx->local_pc);CHKERRQ(ierr);
ierr = PCCreate(PETSC_COMM_SELF,&newpc);CHKERRQ(ierr);
ierr = PCSetOperators(newpc,local_mat,local_mat);CHKERRQ(ierr);
ierr = PCSetType(newpc,PCSHELL);CHKERRQ(ierr);
ierr = PCShellSetContext(newpc,shell_ctx);CHKERRQ(ierr);
ierr = PCShellSetApply(newpc,PCBDDCApplyNullSpaceCorrectionPC);CHKERRQ(ierr);
ierr = PCShellSetDestroy(newpc,PCBDDCDestroyNullSpaceCorrectionPC);CHKERRQ(ierr);
ierr = PCSetUp(newpc);CHKERRQ(ierr);
ierr = KSPSetPC(local_ksp,newpc);CHKERRQ(ierr);
ierr = PCDestroy(&newpc);CHKERRQ(ierr);
ierr = KSPSetUp(local_ksp);CHKERRQ(ierr);
}
/* test */
if (pcbddc->dbg_flag && basis_dofs) {
KSP check_ksp;
PC check_pc;
Mat test_mat;
Vec work3;
PetscReal test_err,lambda_min,lambda_max;
PetscBool setsym,issym=PETSC_FALSE;
PetscInt tabs;
ierr = PetscViewerASCIIGetTab(pcbddc->dbg_viewer,&tabs);CHKERRQ(ierr);
ierr = KSPGetPC(local_ksp,&check_pc);CHKERRQ(ierr);
ierr = VecDuplicate(shell_ctx->work_full_1,&work1);CHKERRQ(ierr);
ierr = VecDuplicate(shell_ctx->work_full_1,&work2);CHKERRQ(ierr);
ierr = VecDuplicate(shell_ctx->work_full_1,&work3);CHKERRQ(ierr);
ierr = VecSetRandom(shell_ctx->work_small_1,NULL);CHKERRQ(ierr);
ierr = MatMult(shell_ctx->basis_mat,shell_ctx->work_small_1,work1);CHKERRQ(ierr);
ierr = VecCopy(work1,work2);CHKERRQ(ierr);
ierr = MatMult(local_mat,work1,work3);CHKERRQ(ierr);
ierr = PCApply(check_pc,work3,work1);CHKERRQ(ierr);
ierr = VecAXPY(work1,m_one,work2);CHKERRQ(ierr);
ierr = VecNorm(work1,NORM_INFINITY,&test_err);CHKERRQ(ierr);
ierr = PetscViewerASCIISynchronizedPrintf(pcbddc->dbg_viewer,"Subdomain %04d error for nullspace correction for ",PetscGlobalRank);CHKERRQ(ierr);
ierr = PetscViewerASCIIUseTabs(pcbddc->dbg_viewer,PETSC_FALSE);CHKERRQ(ierr);
if (isdir) {
ierr = PetscViewerASCIISynchronizedPrintf(pcbddc->dbg_viewer,"Dirichlet ");CHKERRQ(ierr);
} else {
ierr = PetscViewerASCIISynchronizedPrintf(pcbddc->dbg_viewer,"Neumann ");CHKERRQ(ierr);
}
ierr = PetscViewerASCIISynchronizedPrintf(pcbddc->dbg_viewer,"solver is :%1.14e\n",test_err);CHKERRQ(ierr);
ierr = PetscViewerASCIISetTab(pcbddc->dbg_viewer,tabs);CHKERRQ(ierr);
ierr = PetscViewerASCIIUseTabs(pcbddc->dbg_viewer,PETSC_TRUE);CHKERRQ(ierr);
ierr = MatTransposeMatMult(shell_ctx->Lbasis_mat,shell_ctx->Kbasis_mat,MAT_INITIAL_MATRIX,PETSC_DEFAULT,&test_mat);CHKERRQ(ierr);
ierr = MatShift(test_mat,one);CHKERRQ(ierr);
ierr = MatNorm(test_mat,NORM_INFINITY,&test_err);CHKERRQ(ierr);
ierr = MatDestroy(&test_mat);CHKERRQ(ierr);
ierr = PetscViewerASCIISynchronizedPrintf(pcbddc->dbg_viewer,"Subdomain %04d error for nullspace matrices is :%1.14e\n",PetscGlobalRank,test_err);CHKERRQ(ierr);
/* Create ksp object suitable for extreme eigenvalues' estimation */
ierr = KSPCreate(PETSC_COMM_SELF,&check_ksp);CHKERRQ(ierr);
ierr = KSPSetErrorIfNotConverged(check_ksp,pc->erroriffailure);CHKERRQ(ierr);
ierr = KSPSetOperators(check_ksp,local_mat,local_mat);CHKERRQ(ierr);
ierr = KSPSetTolerances(check_ksp,1.e-8,1.e-8,PETSC_DEFAULT,basis_dofs);CHKERRQ(ierr);
ierr = KSPSetComputeSingularValues(check_ksp,PETSC_TRUE);CHKERRQ(ierr);
ierr = MatIsSymmetricKnown(pc->pmat,&setsym,&issym);CHKERRQ(ierr);
if (issym) {
ierr = KSPSetType(check_ksp,KSPCG);CHKERRQ(ierr);
}
ierr = KSPSetPC(check_ksp,check_pc);CHKERRQ(ierr);
ierr = KSPSetUp(check_ksp);CHKERRQ(ierr);
ierr = VecSetRandom(work1,NULL);CHKERRQ(ierr);
ierr = MatMult(local_mat,work1,work2);CHKERRQ(ierr);
ierr = KSPSolve(check_ksp,work2,work2);CHKERRQ(ierr);
ierr = VecAXPY(work2,m_one,work1);CHKERRQ(ierr);
ierr = VecNorm(work2,NORM_INFINITY,&test_err);CHKERRQ(ierr);
ierr = KSPComputeExtremeSingularValues(check_ksp,&lambda_max,&lambda_min);CHKERRQ(ierr);
ierr = KSPGetIterationNumber(check_ksp,&k);CHKERRQ(ierr);
ierr = PetscViewerASCIISynchronizedPrintf(pcbddc->dbg_viewer,"Subdomain %04d error for adapted KSP %1.14e (it %d, eigs %1.6e %1.6e)\n",PetscGlobalRank,test_err,k,lambda_min,lambda_max);CHKERRQ(ierr);
ierr = KSPDestroy(&check_ksp);CHKERRQ(ierr);
ierr = VecDestroy(&work1);CHKERRQ(ierr);
ierr = VecDestroy(&work2);CHKERRQ(ierr);
ierr = VecDestroy(&work3);CHKERRQ(ierr);
}
/* all processes shoud call this, even the void ones */
if (pcbddc->dbg_flag) {
ierr = PetscViewerFlush(pcbddc->dbg_viewer);CHKERRQ(ierr);
}
PetscFunctionReturn(0);
}
EXTERN_C_BEGIN
#undef __FUNCT__
#define __FUNCT__ "KSPCreate_SpecEst"
/*MC
KSPSPECEST - Estimate the spectrum on the first KSPSolve, then use cheaper smoother for subsequent solves.
Options Database Keys:
+ -ksp_specest_minfactor <0.9> - Multiplier on the minimum eigen/singular value
. -ksp_specest_maxfactor <1.1> - Multiplier on the maximum eigen/singular value
. -ksp_specest_richfactor <1> - Multiplier on the richimum eigen/singular value
. -specest_ksp_type <type> - KSP used to estimate the spectrum (usually CG or GMRES)
. -speccheap_ksp_type <type> - KSP used as a cheap smoother once the spectrum has been estimated (usually Chebyshev or Richardson)
- see KSPSolve() for more
Notes:
This KSP estimates the extremal singular values on the first pass, then uses them to configure a smoother that
uses fewer dot products. It is intended for use on the levels of multigrid, especially at high process counts,
where dot products are very expensive.
The same PC is used for both the estimator and the cheap smoother, it is only set up once. There are no options
keys for -specest_pc_ or speccheap_pc_ since it is the same object as -pc_.
Level: intermediate
.seealso: KSPCreate(), KSPSetType(), KSPType (for list of available types), KSP, KSPGMRES, KSPCG, KSPCHEBYSHEV, KSPRICHARDSON
M*/
PetscErrorCode KSPCreate_SpecEst(KSP ksp)
{
KSP_SpecEst *spec;
PetscErrorCode ierr;
PetscFunctionBegin;
ierr = KSPSetSupportedNorm(ksp,KSP_NORM_PRECONDITIONED,PC_LEFT,2);CHKERRQ(ierr);
ierr = KSPSetSupportedNorm(ksp,KSP_NORM_PRECONDITIONED,PC_RIGHT,1);CHKERRQ(ierr);
ierr = KSPSetSupportedNorm(ksp,KSP_NORM_UNPRECONDITIONED,PC_LEFT,1);CHKERRQ(ierr);
ierr = KSPSetSupportedNorm(ksp,KSP_NORM_UNPRECONDITIONED,PC_RIGHT,1);CHKERRQ(ierr);
ierr = PetscNewLog(ksp,KSP_SpecEst,&spec);CHKERRQ(ierr);
ksp->data = (void*)spec;
ksp->ops->setup = KSPSetUp_SpecEst;
ksp->ops->solve = KSPSolve_SpecEst;
ksp->ops->destroy = KSPDestroy_SpecEst;
ksp->ops->buildsolution = KSPDefaultBuildSolution;
ksp->ops->buildresidual = KSPDefaultBuildResidual;
ksp->ops->setfromoptions = KSPSetFromOptions_SpecEst;
ksp->ops->view = KSPView_SpecEst;
spec->minfactor = 0.9;
spec->maxfactor = 1.1;
spec->richfactor = 1.0;
ierr = KSPCreate(((PetscObject)ksp)->comm,&spec->kspest);CHKERRQ(ierr);
ierr = KSPCreate(((PetscObject)ksp)->comm,&spec->kspcheap);CHKERRQ(ierr);
/* Hold an empty PC */
ierr = KSPGetPC(spec->kspest,&spec->pcnone);CHKERRQ(ierr);
ierr = PetscObjectReference((PetscObject)spec->pcnone);CHKERRQ(ierr);
ierr = PCSetType(spec->pcnone,PCNONE);CHKERRQ(ierr);
ierr = KSPSetPC(spec->kspcheap,spec->pcnone);CHKERRQ(ierr);
ierr = KSPSetTolerances(spec->kspest,PETSC_DEFAULT,PETSC_DEFAULT,PETSC_DEFAULT,5);CHKERRQ(ierr);
/* Make the "cheap" preconditioner cheap by default */
ierr = KSPSetConvergenceTest(spec->kspcheap,KSPSkipConverged,0,0);CHKERRQ(ierr);
ierr = KSPSetNormType(spec->kspcheap,KSP_NORM_NONE);CHKERRQ(ierr);
ierr = KSPSetTolerances(spec->kspcheap,PETSC_DEFAULT,PETSC_DEFAULT,PETSC_DEFAULT,5);CHKERRQ(ierr);
PetscFunctionReturn(0);
}
int main(int argc,char **args)
{
Mat mat; /* matrix */
Vec b,ustar,u; /* vectors (RHS, exact solution, approx solution) */
PC pc; /* PC context */
KSP ksp; /* KSP context */
PetscErrorCode ierr;
PetscInt n = 10,i,its,col[3];
PetscScalar value[3];
PCType pcname;
KSPType kspname;
PetscReal norm,tol=1000.*PETSC_MACHINE_EPSILON;
PetscInitialize(&argc,&args,(char*)0,help);
/* Create and initialize vectors */
ierr = VecCreateSeq(PETSC_COMM_SELF,n,&b);CHKERRQ(ierr);
ierr = VecCreateSeq(PETSC_COMM_SELF,n,&ustar);CHKERRQ(ierr);
ierr = VecCreateSeq(PETSC_COMM_SELF,n,&u);CHKERRQ(ierr);
ierr = VecSet(ustar,1.0);CHKERRQ(ierr);
ierr = VecSet(u,0.0);CHKERRQ(ierr);
/* Create and assemble matrix */
ierr = MatCreateSeqAIJ(PETSC_COMM_SELF,n,n,3,NULL,&mat);CHKERRQ(ierr);
value[0] = -1.0; value[1] = 2.0; value[2] = -1.0;
for (i=1; i<n-1; i++) {
col[0] = i-1; col[1] = i; col[2] = i+1;
ierr = MatSetValues(mat,1,&i,3,col,value,INSERT_VALUES);CHKERRQ(ierr);
}
i = n - 1; col[0] = n - 2; col[1] = n - 1;
ierr = MatSetValues(mat,1,&i,2,col,value,INSERT_VALUES);CHKERRQ(ierr);
i = 0; col[0] = 0; col[1] = 1; value[0] = 2.0; value[1] = -1.0;
ierr = MatSetValues(mat,1,&i,2,col,value,INSERT_VALUES);CHKERRQ(ierr);
ierr = MatAssemblyBegin(mat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
ierr = MatAssemblyEnd(mat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
/* Compute right-hand-side vector */
ierr = MatMult(mat,ustar,b);CHKERRQ(ierr);
/* Create PC context and set up data structures */
ierr = PCCreate(PETSC_COMM_WORLD,&pc);CHKERRQ(ierr);
ierr = PCSetType(pc,PCNONE);CHKERRQ(ierr);
ierr = PCSetFromOptions(pc);CHKERRQ(ierr);
ierr = PCSetOperators(pc,mat,mat);CHKERRQ(ierr);
ierr = PCSetUp(pc);CHKERRQ(ierr);
/* Create KSP context and set up data structures */
ierr = KSPCreate(PETSC_COMM_WORLD,&ksp);CHKERRQ(ierr);
ierr = KSPSetType(ksp,KSPRICHARDSON);CHKERRQ(ierr);
ierr = KSPSetFromOptions(ksp);CHKERRQ(ierr);
ierr = PCSetOperators(pc,mat,mat);CHKERRQ(ierr);
ierr = KSPSetPC(ksp,pc);CHKERRQ(ierr);
ierr = KSPSetUp(ksp);CHKERRQ(ierr);
/* Solve the problem */
ierr = KSPGetType(ksp,&kspname);CHKERRQ(ierr);
ierr = PCGetType(pc,&pcname);CHKERRQ(ierr);
ierr = PetscPrintf(PETSC_COMM_SELF,"Running %s with %s preconditioning\n",kspname,pcname);CHKERRQ(ierr);
ierr = KSPSolve(ksp,b,u);CHKERRQ(ierr);
ierr = VecAXPY(u,-1.0,ustar);CHKERRQ(ierr);
ierr = VecNorm(u,NORM_2,&norm);
ierr = KSPGetIterationNumber(ksp,&its);CHKERRQ(ierr);
if (norm > tol) {
ierr = PetscPrintf(PETSC_COMM_SELF,"2 norm of error %g Number of iterations %D\n",(double)norm,its);CHKERRQ(ierr);
}
/* Free data structures */
ierr = KSPDestroy(&ksp);CHKERRQ(ierr);
ierr = VecDestroy(&u);CHKERRQ(ierr);
ierr = VecDestroy(&ustar);CHKERRQ(ierr);
ierr = VecDestroy(&b);CHKERRQ(ierr);
ierr = MatDestroy(&mat);CHKERRQ(ierr);
ierr = PCDestroy(&pc);CHKERRQ(ierr);
ierr = PetscFinalize();
return 0;
}
