Actual source code: hpddm.cxx

  1: #define HPDDM_MIXED_PRECISION 1
  2: #include <petsc/private/petschpddm.h>

  4: const char *const KSPHPDDMTypes[]          = {KSPGMRES, "bgmres", KSPCG, "bcg", "gcrodr", "bgcrodr", "bfbcg", KSPPREONLY};
  5: const char *const HPDDMOrthogonalization[] = {"cgs", "mgs"};
  6: const char *const HPDDMQR[]                = {"cholqr", "cgs", "mgs"};
  7: const char *const HPDDMVariant[]           = {"left", "right", "flexible"};
  8: const char *const HPDDMRecycleTarget[]     = {"SM", "LM", "SR", "LR", "SI", "LI"};
  9: const char *const HPDDMRecycleStrategy[]   = {"A", "B"};

 11: PetscBool  HPDDMCite       = PETSC_FALSE;
 12: const char HPDDMCitation[] = "@article{jolivet2020petsc,\n"
 13:                              "  Author = {Jolivet, Pierre and Roman, Jose E. and Zampini, Stefano},\n"
 14:                              "  Title = {{KSPHPDDM} and {PCHPDDM}: Extending {PETSc} with Robust Overlapping {Schwarz} Preconditioners and Advanced {Krylov} Methods},\n"
 15:                              "  Year = {2021},\n"
 16:                              "  Publisher = {Elsevier},\n"
 17:                              "  Journal = {Computer \\& Mathematics with Applications},\n"
 18:                              "  Volume = {84},\n"
 19:                              "  Pages = {277--295},\n"
 20:                              "  Url = {https://github.com/prj-/jolivet2020petsc}\n"
 21:                              "}\n";

 23: #if PetscDefined(HAVE_SLEPC) && PetscDefined(HAVE_DYNAMIC_LIBRARIES) && PetscDefined(USE_SHARED_LIBRARIES)
 24: static PetscBool loadedDL = PETSC_FALSE;
 25: #endif

 27: static PetscErrorCode KSPSetFromOptions_HPDDM(KSP ksp, PetscOptionItems PetscOptionsObject)
 28: {
 29:   KSP_HPDDM  *data = (KSP_HPDDM *)ksp->data;
 30:   PetscInt    i, j;
 31:   PetscMPIInt size;

 33:   PetscFunctionBegin;
 34:   PetscOptionsHeadBegin(PetscOptionsObject, "KSPHPDDM options, cf. https://github.com/hpddm/hpddm");
 35:   i = (data->cntl[0] == static_cast<char>(PETSC_DECIDE) ? HPDDM_KRYLOV_METHOD_GMRES : data->cntl[0]);
 36:   PetscCall(PetscOptionsEList("-ksp_hpddm_type", "Type of Krylov method", "KSPHPDDMGetType", KSPHPDDMTypes, PETSC_STATIC_ARRAY_LENGTH(KSPHPDDMTypes), KSPHPDDMTypes[HPDDM_KRYLOV_METHOD_GMRES], &i, nullptr));
 37:   if (i == PETSC_STATIC_ARRAY_LENGTH(KSPHPDDMTypes) - 1) i = HPDDM_KRYLOV_METHOD_NONE; /* need to shift the value since HPDDM_KRYLOV_METHOD_RICHARDSON is not registered in PETSc */
 38:   data->cntl[0] = i;
 39:   PetscCall(PetscOptionsEnum("-ksp_hpddm_precision", "Precision in which Krylov bases are stored", "KSPHPDDM", PetscPrecisionTypes, (PetscEnum)data->precision, (PetscEnum *)&data->precision, nullptr));
 40:   PetscCheck(data->precision != PETSC_PRECISION___FLOAT128 || PetscDefined(HAVE_REAL___FLOAT128), PetscObjectComm((PetscObject)ksp), PETSC_ERR_SUP_SYS, "Unsupported %s precision", PetscPrecisionTypes[data->precision]);
 41:   PetscCheck(std::abs(data->precision - PETSC_SCALAR_PRECISION) <= 1, PetscObjectComm((PetscObject)ksp), PETSC_ERR_SUP, "Unsupported mixed %s and %s precisions", PetscPrecisionTypes[data->precision], PetscPrecisionTypes[PETSC_SCALAR_PRECISION]);
 42:   PetscCheck(data->precision != PETSC_PRECISION_INVALID && data->precision != PETSC_PRECISION_BFLOAT16, PetscObjectComm((PetscObject)ksp), PETSC_ERR_SUP, "Unsupported PetscPrecision %s", PetscPrecisionTypes[data->precision]);
 43:   static_assert(PETSC_PRECISION___FP16 == PETSC_PRECISION_SINGLE - 1 && PETSC_PRECISION_SINGLE == PETSC_PRECISION_DOUBLE - 1 && PETSC_PRECISION_DOUBLE == PETSC_PRECISION___FLOAT128 - 1, "");
 44:   if (data->cntl[0] != HPDDM_KRYLOV_METHOD_NONE) {
 45:     if (data->cntl[0] != HPDDM_KRYLOV_METHOD_BCG && data->cntl[0] != HPDDM_KRYLOV_METHOD_BFBCG) {
 46:       i = (data->cntl[1] == static_cast<char>(PETSC_DECIDE) ? HPDDM_VARIANT_LEFT : data->cntl[1]);
 47:       if (ksp->pc_side_set == PC_SIDE_DEFAULT)
 48:         PetscCall(PetscOptionsEList("-ksp_hpddm_variant", "Left, right, or variable preconditioning", "KSPHPDDM", HPDDMVariant, PETSC_STATIC_ARRAY_LENGTH(HPDDMVariant), HPDDMVariant[HPDDM_VARIANT_LEFT], &i, nullptr));
 49:       else if (ksp->pc_side_set == PC_RIGHT) i = HPDDM_VARIANT_RIGHT;
 50:       data->cntl[1] = i;
 51:       if (i > 0) PetscCall(KSPSetPCSide(ksp, PC_RIGHT));
 52:     }
 53:     if (data->cntl[0] == HPDDM_KRYLOV_METHOD_BGMRES || data->cntl[0] == HPDDM_KRYLOV_METHOD_BGCRODR || data->cntl[0] == HPDDM_KRYLOV_METHOD_BFBCG) {
 54:       data->rcntl[0] = (PetscAbsReal(data->rcntl[0] - static_cast<PetscReal>(PETSC_DECIDE)) < PETSC_SMALL ? -1.0 : data->rcntl[0]);
 55:       PetscCall(PetscOptionsReal("-ksp_hpddm_deflation_tol", "Tolerance when deflating right-hand sides inside block methods", "KSPHPDDM", data->rcntl[0], data->rcntl, nullptr));
 56:       i = (data->scntl[data->cntl[0] != HPDDM_KRYLOV_METHOD_BFBCG] == static_cast<unsigned short>(PETSC_DECIDE) ? 1 : PetscMax(1, data->scntl[data->cntl[0] != HPDDM_KRYLOV_METHOD_BFBCG]));
 57:       PetscCall(PetscOptionsRangeInt("-ksp_hpddm_enlarge_krylov_subspace", "Split the initial right-hand side into multiple vectors", "KSPHPDDM", i, &i, nullptr, 1, std::numeric_limits<unsigned short>::max() - 1));
 58:       data->scntl[data->cntl[0] != HPDDM_KRYLOV_METHOD_BFBCG] = i;
 59:     } else data->scntl[data->cntl[0] != HPDDM_KRYLOV_METHOD_BCG] = 0;
 60:     if (data->cntl[0] == HPDDM_KRYLOV_METHOD_GMRES || data->cntl[0] == HPDDM_KRYLOV_METHOD_BGMRES || data->cntl[0] == HPDDM_KRYLOV_METHOD_GCRODR || data->cntl[0] == HPDDM_KRYLOV_METHOD_BGCRODR) {
 61:       i = (data->cntl[2] == static_cast<char>(PETSC_DECIDE) ? HPDDM_ORTHOGONALIZATION_CGS : data->cntl[2] & 3);
 62:       PetscCall(PetscOptionsEList("-ksp_hpddm_orthogonalization", "Classical (faster) or Modified (more robust) Gram--Schmidt process", "KSPHPDDM", HPDDMOrthogonalization, PETSC_STATIC_ARRAY_LENGTH(HPDDMOrthogonalization), HPDDMOrthogonalization[HPDDM_ORTHOGONALIZATION_CGS], &i, nullptr));
 63:       j = (data->cntl[2] == static_cast<char>(PETSC_DECIDE) ? HPDDM_QR_CHOLQR : ((data->cntl[2] >> 2) & 7));
 64:       PetscCall(PetscOptionsEList("-ksp_hpddm_qr", "Distributed QR factorizations computed with Cholesky QR, Classical or Modified Gram--Schmidt process", "KSPHPDDM", HPDDMQR, PETSC_STATIC_ARRAY_LENGTH(HPDDMQR), HPDDMQR[HPDDM_QR_CHOLQR], &j, nullptr));
 65:       data->cntl[2] = static_cast<char>(i) + (static_cast<char>(j) << 2);
 66:       i             = (data->scntl[0] == static_cast<unsigned short>(PETSC_DECIDE) ? PetscMin(30, ksp->max_it) : data->scntl[0]);
 67:       PetscCall(PetscOptionsRangeInt("-ksp_gmres_restart", "Maximum number of Arnoldi vectors generated per cycle", "KSPHPDDM", i, &i, nullptr, PetscMin(1, ksp->max_it), PetscMin(ksp->max_it, std::numeric_limits<unsigned short>::max() - 1)));
 68:       data->scntl[0] = i;
 69:     }
 70:     if (data->cntl[0] == HPDDM_KRYLOV_METHOD_BCG || data->cntl[0] == HPDDM_KRYLOV_METHOD_BFBCG) {
 71:       j = (data->cntl[1] == static_cast<char>(PETSC_DECIDE) ? HPDDM_QR_CHOLQR : data->cntl[1]);
 72:       PetscCall(PetscOptionsEList("-ksp_hpddm_qr", "Distributed QR factorizations computed with Cholesky QR, Classical or Modified Gram--Schmidt process", "KSPHPDDM", HPDDMQR, PETSC_STATIC_ARRAY_LENGTH(HPDDMQR), HPDDMQR[HPDDM_QR_CHOLQR], &j, nullptr));
 73:       data->cntl[1] = j;
 74:     }
 75:     if (data->cntl[0] == HPDDM_KRYLOV_METHOD_GCRODR || data->cntl[0] == HPDDM_KRYLOV_METHOD_BGCRODR) {
 76:       i = (data->icntl[0] == static_cast<int>(PETSC_DECIDE) ? PetscMin(20, data->scntl[0] - 1) : data->icntl[0]);
 77:       PetscCall(PetscOptionsRangeInt("-ksp_hpddm_recycle", "Number of harmonic Ritz vectors to compute", "KSPHPDDM", i, &i, nullptr, 1, data->scntl[0] - 1));
 78:       data->icntl[0] = i;
 79:       if (!PetscDefined(HAVE_SLEPC) || !PetscDefined(USE_SHARED_LIBRARIES) || data->cntl[0] == HPDDM_KRYLOV_METHOD_GCRODR) {
 80:         i = (data->cntl[3] == static_cast<char>(PETSC_DECIDE) ? HPDDM_RECYCLE_TARGET_SM : data->cntl[3]);
 81:         PetscCall(PetscOptionsEList("-ksp_hpddm_recycle_target", "Criterion to select harmonic Ritz vectors", "KSPHPDDM", HPDDMRecycleTarget, PETSC_STATIC_ARRAY_LENGTH(HPDDMRecycleTarget), HPDDMRecycleTarget[HPDDM_RECYCLE_TARGET_SM], &i, nullptr));
 82:         data->cntl[3] = i;
 83:       } else {
 84:         PetscCheck(data->precision == PETSC_SCALAR_PRECISION, PetscObjectComm((PetscObject)ksp), PETSC_ERR_ARG_INCOMP, "Cannot use SLEPc with a different precision than PETSc for harmonic Ritz eigensolves");
 85:         PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)ksp), &size));
 86:         i = (data->cntl[3] == static_cast<char>(PETSC_DECIDE) ? 1 : data->cntl[3]);
 87:         PetscCall(PetscOptionsRangeInt("-ksp_hpddm_recycle_redistribute", "Number of processes used to solve eigenvalue problems when recycling in BGCRODR", "KSPHPDDM", i, &i, nullptr, 1, PetscMin(size, 192)));
 88:         data->cntl[3] = i;
 89:       }
 90:       i = (data->cntl[4] == static_cast<char>(PETSC_DECIDE) ? HPDDM_RECYCLE_STRATEGY_A : data->cntl[4]);
 91:       PetscCall(PetscOptionsEList("-ksp_hpddm_recycle_strategy", "Generalized eigenvalue problem to solve for recycling", "KSPHPDDM", HPDDMRecycleStrategy, PETSC_STATIC_ARRAY_LENGTH(HPDDMRecycleStrategy), HPDDMRecycleStrategy[HPDDM_RECYCLE_STRATEGY_A], &i, nullptr));
 92:       data->cntl[4] = i;
 93:     }
 94:   } else {
 95:     data->cntl[0]  = HPDDM_KRYLOV_METHOD_NONE;
 96:     data->scntl[1] = 1;
 97:   }
 98:   PetscCheck(ksp->nmax >= std::numeric_limits<int>::min() && ksp->nmax <= std::numeric_limits<int>::max(), PetscObjectComm((PetscObject)ksp), PETSC_ERR_ARG_OUTOFRANGE, "KSPMatSolve() block size %" PetscInt_FMT " not representable by an integer, which is not handled by KSPHPDDM",
 99:              ksp->nmax);
100:   data->icntl[1] = static_cast<int>(ksp->nmax);
101:   PetscOptionsHeadEnd();
102:   PetscFunctionReturn(PETSC_SUCCESS);
103: }

105: static PetscErrorCode KSPView_HPDDM(KSP ksp, PetscViewer viewer)
106: {
107:   KSP_HPDDM            *data  = (KSP_HPDDM *)ksp->data;
108:   HPDDM::PETScOperator *op    = data->op;
109:   const PetscScalar    *array = op ? op->storage() : nullptr;
110:   PetscBool             ascii;

112:   PetscFunctionBegin;
113:   PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERASCII, &ascii));
114:   if (op && ascii) {
115:     PetscCall(PetscViewerASCIIPrintf(viewer, "HPDDM type: %s%s\n", KSPHPDDMTypes[std::min(static_cast<PetscInt>(data->cntl[0]), static_cast<PetscInt>(PETSC_STATIC_ARRAY_LENGTH(KSPHPDDMTypes) - 1))], data->cntl[1] == HPDDM_VARIANT_FLEXIBLE ? " (with support for variable preconditioning)" : ""));
116:     PetscCall(PetscViewerASCIIPrintf(viewer, "precision: %s\n", PetscPrecisionTypes[data->precision]));
117:     if (data->cntl[0] == HPDDM_KRYLOV_METHOD_BGMRES || data->cntl[0] == HPDDM_KRYLOV_METHOD_BGCRODR || data->cntl[0] == HPDDM_KRYLOV_METHOD_BFBCG) {
118:       if (PetscAbsReal(data->rcntl[0] - static_cast<PetscReal>(PETSC_DECIDE)) < PETSC_SMALL) PetscCall(PetscViewerASCIIPrintf(viewer, "no deflation at restarts\n"));
119:       else PetscCall(PetscViewerASCIIPrintf(viewer, "deflation tolerance: %g\n", static_cast<double>(data->rcntl[0])));
120:     }
121:     if (data->cntl[0] == HPDDM_KRYLOV_METHOD_GCRODR || data->cntl[0] == HPDDM_KRYLOV_METHOD_BGCRODR) {
122:       PetscCall(PetscViewerASCIIPrintf(viewer, "deflation subspace attached? %s\n", PetscBools[array ? PETSC_TRUE : PETSC_FALSE]));
123:       if (!PetscDefined(HAVE_SLEPC) || !PetscDefined(USE_SHARED_LIBRARIES) || data->cntl[0] == HPDDM_KRYLOV_METHOD_GCRODR) PetscCall(PetscViewerASCIIPrintf(viewer, "deflation target: %s\n", HPDDMRecycleTarget[static_cast<PetscInt>(data->cntl[3])]));
124:       else PetscCall(PetscViewerASCIIPrintf(viewer, "redistribution size: %d\n", static_cast<PetscMPIInt>(data->cntl[3])));
125:     }
126:     if (data->icntl[1] != static_cast<int>(PETSC_DECIDE)) PetscCall(PetscViewerASCIIPrintf(viewer, "  block size is %d\n", data->icntl[1]));
127:   }
128:   PetscFunctionReturn(PETSC_SUCCESS);
129: }

131: static PetscErrorCode KSPSetUp_HPDDM(KSP ksp)
132: {
133:   KSP_HPDDM *data = (KSP_HPDDM *)ksp->data;
134:   Mat        A;
135:   PetscInt   n, bs;
136:   PetscBool  match;

138:   PetscFunctionBegin;
139:   PetscCall(KSPGetOperators(ksp, &A, nullptr));
140:   PetscCall(MatGetLocalSize(A, &n, nullptr));
141:   PetscCall(MatGetBlockSize(A, &bs));
142:   PetscCall(PetscObjectTypeCompareAny((PetscObject)A, &match, MATSEQKAIJ, MATMPIKAIJ, ""));
143:   if (match) n /= bs;
144:   data->op = new HPDDM::PETScOperator(ksp, n);
145:   if (PetscUnlikely(!ksp->setfromoptionscalled || data->cntl[0] == static_cast<char>(PETSC_DECIDE))) { /* what follows is basically a copy/paste of KSPSetFromOptions_HPDDM, with no call to PetscOptions() */
146:     PetscCall(PetscInfo(ksp, "KSPSetFromOptions() not called or uninitialized internal structure, hardwiring default KSPHPDDM options\n"));
147:     if (data->cntl[0] == static_cast<char>(PETSC_DECIDE)) data->cntl[0] = 0; /* GMRES by default */
148:     if (data->cntl[0] != HPDDM_KRYLOV_METHOD_NONE) {                         /* following options do not matter with PREONLY */
149:       if (data->cntl[0] != HPDDM_KRYLOV_METHOD_BCG && data->cntl[0] != HPDDM_KRYLOV_METHOD_BFBCG) {
150:         data->cntl[1] = HPDDM_VARIANT_LEFT; /* left preconditioning by default */
151:         if (ksp->pc_side_set == PC_RIGHT) data->cntl[1] = HPDDM_VARIANT_RIGHT;
152:         if (data->cntl[1] > 0) PetscCall(KSPSetPCSide(ksp, PC_RIGHT));
153:       }
154:       if (data->cntl[0] == HPDDM_KRYLOV_METHOD_BGMRES || data->cntl[0] == HPDDM_KRYLOV_METHOD_BGCRODR || data->cntl[0] == HPDDM_KRYLOV_METHOD_BFBCG) {
155:         data->rcntl[0]                                          = -1.0; /* no deflation by default */
156:         data->scntl[data->cntl[0] != HPDDM_KRYLOV_METHOD_BFBCG] = 1;    /* Krylov subspace not enlarged by default */
157:       } else data->scntl[data->cntl[0] != HPDDM_KRYLOV_METHOD_BCG] = 0;
158:       if (data->cntl[0] == HPDDM_KRYLOV_METHOD_GMRES || data->cntl[0] == HPDDM_KRYLOV_METHOD_BGMRES || data->cntl[0] == HPDDM_KRYLOV_METHOD_GCRODR || data->cntl[0] == HPDDM_KRYLOV_METHOD_BGCRODR) {
159:         data->cntl[2]  = static_cast<char>(HPDDM_ORTHOGONALIZATION_CGS) + (static_cast<char>(HPDDM_QR_CHOLQR) << 2); /* CGS and CholQR by default */
160:         data->scntl[0] = PetscMin(30, ksp->max_it);                                                                  /* restart parameter of 30 by default */
161:       }
162:       if (data->cntl[0] == HPDDM_KRYLOV_METHOD_BCG || data->cntl[0] == HPDDM_KRYLOV_METHOD_BFBCG) data->cntl[1] = HPDDM_QR_CHOLQR; /* CholQR by default */
163:       if (data->cntl[0] == HPDDM_KRYLOV_METHOD_GCRODR || data->cntl[0] == HPDDM_KRYLOV_METHOD_BGCRODR) {
164:         data->icntl[0] = PetscMin(20, data->scntl[0] - 1); /* recycled subspace of size 20 by default */
165:         if (!PetscDefined(HAVE_SLEPC) || !PetscDefined(USE_SHARED_LIBRARIES) || data->cntl[0] == HPDDM_KRYLOV_METHOD_GCRODR) {
166:           data->cntl[3] = HPDDM_RECYCLE_TARGET_SM; /* default recycling target */
167:         } else {
168:           data->cntl[3] = 1; /* redistribution parameter of 1 by default */
169:         }
170:         data->cntl[4] = HPDDM_RECYCLE_STRATEGY_A; /* default recycling strategy */
171:       }
172:     } else data->scntl[1] = 1;
173:   }
174:   PetscCheck(ksp->nmax >= std::numeric_limits<int>::min() && ksp->nmax <= std::numeric_limits<int>::max(), PetscObjectComm((PetscObject)ksp), PETSC_ERR_ARG_OUTOFRANGE, "KSPMatSolve() block size %" PetscInt_FMT " not representable by an integer, which is not handled by KSPHPDDM",
175:              ksp->nmax);
176:   data->icntl[1] = static_cast<int>(ksp->nmax);
177:   PetscFunctionReturn(PETSC_SUCCESS);
178: }

180: static inline PetscErrorCode KSPReset_HPDDM_Private(KSP ksp)
181: {
182:   KSP_HPDDM *data = (KSP_HPDDM *)ksp->data;

184:   PetscFunctionBegin;
185:   /* cast PETSC_DECIDE into the appropriate types to avoid compiler warnings */
186:   std::fill_n(data->rcntl, PETSC_STATIC_ARRAY_LENGTH(data->rcntl), static_cast<PetscReal>(PETSC_DECIDE));
187:   std::fill_n(data->icntl, PETSC_STATIC_ARRAY_LENGTH(data->icntl), static_cast<int>(PETSC_DECIDE));
188:   std::fill_n(data->scntl, PETSC_STATIC_ARRAY_LENGTH(data->scntl), static_cast<unsigned short>(PETSC_DECIDE));
189:   std::fill_n(data->cntl, PETSC_STATIC_ARRAY_LENGTH(data->cntl), static_cast<char>(PETSC_DECIDE));
190:   data->precision = PETSC_SCALAR_PRECISION;
191:   PetscFunctionReturn(PETSC_SUCCESS);
192: }

194: static PetscErrorCode KSPReset_HPDDM(KSP ksp)
195: {
196:   KSP_HPDDM *data = (KSP_HPDDM *)ksp->data;

198:   PetscFunctionBegin;
199:   delete data->op;
200:   data->op = nullptr;
201:   PetscCall(KSPReset_HPDDM_Private(ksp));
202:   PetscFunctionReturn(PETSC_SUCCESS);
203: }

205: static PetscErrorCode KSPDestroy_HPDDM(KSP ksp)
206: {
207:   PetscFunctionBegin;
208:   PetscCall(KSPReset_HPDDM(ksp));
209:   PetscCall(KSPDestroyDefault(ksp));
210:   PetscCall(PetscObjectComposeFunction((PetscObject)ksp, "KSPHPDDMSetDeflationMat_C", nullptr));
211:   PetscCall(PetscObjectComposeFunction((PetscObject)ksp, "KSPHPDDMGetDeflationMat_C", nullptr));
212:   PetscCall(PetscObjectComposeFunction((PetscObject)ksp, "KSPHPDDMSetType_C", nullptr));
213:   PetscCall(PetscObjectComposeFunction((PetscObject)ksp, "KSPHPDDMGetType_C", nullptr));
214:   PetscFunctionReturn(PETSC_SUCCESS);
215: }

217: template <PetscMemType type = PETSC_MEMTYPE_HOST>
218: static inline PetscErrorCode KSPSolve_HPDDM_Private(KSP ksp, const PetscScalar *b, PetscScalar *x, PetscInt n)
219: {
220:   KSP_HPDDM              *data = (KSP_HPDDM *)ksp->data;
221:   KSPConvergedDefaultCtx *ctx  = (KSPConvergedDefaultCtx *)ksp->cnvP;
222:   const PetscInt          N    = data->op->getDof() * n;
223:   PetscBool               flg;
224: #if !PetscDefined(USE_REAL_DOUBLE) || PetscDefined(HAVE_F2CBLASLAPACK___FLOAT128_BINDINGS)
225:   HPDDM::upscaled_type<PetscScalar> *high[2];
226: #endif
227: #if !PetscDefined(USE_REAL_SINGLE) || PetscDefined(HAVE_F2CBLASLAPACK___FP16_BINDINGS)
228:   typedef HPDDM::downscaled_type<PetscReal> PetscDownscaledReal PETSC_ATTRIBUTE_MAY_ALIAS;
229:   #if !PetscDefined(USE_COMPLEX)
230:   PetscDownscaledReal *low[2];
231:   #else
232:   typedef PetscReal PetscAliasedReal   PETSC_ATTRIBUTE_MAY_ALIAS;
233:   HPDDM::downscaled_type<PetscScalar> *low[2];
234:   PetscAliasedReal                    *x_r;
235:   PetscDownscaledReal                 *low_r;
236:   #endif
237: #endif
238: #if PetscDefined(HAVE_CUDA)
239:   Mat     A;
240:   VecType vtype;
241: #endif

243:   PetscFunctionBegin;
244: #if PetscDefined(HAVE_CUDA)
245:   PetscCall(KSPGetOperators(ksp, &A, nullptr));
246:   PetscCall(MatGetVecType(A, &vtype));
247:   std::initializer_list<std::string>                 list = {VECCUDA, VECSEQCUDA, VECMPICUDA};
248:   std::initializer_list<std::string>::const_iterator it   = std::find(list.begin(), list.end(), std::string(vtype));
249:   PetscCheck(type != PETSC_MEMTYPE_HOST || it == list.end(), PetscObjectComm((PetscObject)ksp), PETSC_ERR_SUP, "MatGetVecType() must return a Vec with the same PetscMemType as the right-hand side and solution, PetscMemType(%s) != %s", vtype, PetscMemTypeToString(type));
250: #endif
251:   PetscCall(PCGetDiagonalScale(ksp->pc, &flg));
252:   PetscCheck(!flg, PetscObjectComm((PetscObject)ksp), PETSC_ERR_SUP, "Krylov method %s does not support diagonal scaling", ((PetscObject)ksp)->type_name);
253:   if (n > 1) {
254:     if (ksp->converged == KSPConvergedDefault) {
255:       PetscCheck(!ctx->mininitialrtol, PetscObjectComm((PetscObject)ksp), PETSC_ERR_SUP, "Krylov method %s does not support KSPConvergedDefaultSetUMIRNorm()", ((PetscObject)ksp)->type_name);
256:       if (!ctx->initialrtol) {
257:         PetscCall(PetscInfo(ksp, "Forcing KSPConvergedDefaultSetUIRNorm() since KSPConvergedDefault() cannot handle multiple norms\n"));
258:         ctx->initialrtol = PETSC_TRUE;
259:       }
260:     } else PetscCall(PetscInfo(ksp, "Using a special \"converged\" callback, be careful, it is used in KSPHPDDM to track blocks of residuals\n"));
261:   }
262:   /* initial guess is always nonzero with recycling methods if there is a deflation subspace available */
263:   if ((data->cntl[0] == HPDDM_KRYLOV_METHOD_GCRODR || data->cntl[0] == HPDDM_KRYLOV_METHOD_BGCRODR) && data->op->storage()) ksp->guess_zero = PETSC_FALSE;
264:   ksp->its    = 0;
265:   ksp->reason = KSP_CONVERGED_ITERATING;
266:   if (data->precision > PETSC_SCALAR_PRECISION) { /* Krylov basis stored in higher precision than PetscScalar */
267: #if !PetscDefined(USE_REAL_DOUBLE) || PetscDefined(HAVE_F2CBLASLAPACK___FLOAT128_BINDINGS)
268:     if (type == PETSC_MEMTYPE_HOST) {
269:       PetscCall(PetscMalloc2(N, high, N, high + 1));
270:       HPDDM::copy_n(b, N, high[0]);
271:       HPDDM::copy_n(x, N, high[1]);
272:       PetscCall(HPDDM::IterativeMethod::solve(*data->op, high[0], high[1], n, PetscObjectComm((PetscObject)ksp)));
273:       HPDDM::copy_n(high[1], N, x);
274:       PetscCall(PetscFree2(high[0], high[1]));
275:     } else {
276:       PetscCheck(PetscDefined(HAVE_CUDA) && PetscDefined(USE_REAL_SINGLE), PetscObjectComm((PetscObject)ksp), PETSC_ERR_SUP, "CUDA in PETSc has no support for precisions other than single or double");
277:   #if PetscDefined(HAVE_CUDA)
278:     #if PetscDefined(HAVE_HPDDM)
279:       PetscCall(KSPSolve_HPDDM_CUDA_Private(data, b, x, n, PetscObjectComm((PetscObject)ksp)));
280:     #else
281:       SETERRQ(PetscObjectComm((PetscObject)ksp), PETSC_ERR_SUP, "No CUDA support with --download-hpddm from SLEPc");
282:     #endif
283:   #endif
284:     }
285: #else
286:     PetscCheck(data->precision != PETSC_PRECISION___FLOAT128, PetscObjectComm((PetscObject)ksp), PETSC_ERR_SUP, "Reconfigure with --download-f2cblaslapack --with-f2cblaslapack-float128-bindings");
287: #endif
288:   } else if (data->precision < PETSC_SCALAR_PRECISION) { /* Krylov basis stored in lower precision than PetscScalar */
289: #if !PetscDefined(USE_REAL_SINGLE) || PetscDefined(HAVE_F2CBLASLAPACK___FP16_BINDINGS)
290:     if (type == PETSC_MEMTYPE_HOST) {
291:       PetscCall(PetscMalloc1(N, low));
292:   #if !PetscDefined(USE_COMPLEX)
293:       low[1] = reinterpret_cast<PetscDownscaledReal *>(x);
294:   #else
295:       low[1] = reinterpret_cast<HPDDM::downscaled_type<PetscScalar> *>(x);
296:   #endif
297:       std::copy_n(b, N, low[0]);
298:       for (PetscInt i = 0; i < N; ++i) low[1][i] = x[i];
299:       PetscCall(HPDDM::IterativeMethod::solve(*data->op, low[0], low[1], n, PetscObjectComm((PetscObject)ksp)));
300:   #if !PetscDefined(USE_COMPLEX)
301:       for (PetscInt i = N; i-- > 0;) x[i] = static_cast<PetscScalar>(low[1][i]);
302:   #else
303:       x_r = reinterpret_cast<PetscAliasedReal *>(x), low_r = reinterpret_cast<PetscDownscaledReal *>(x_r);
304:       for (PetscInt i = 2 * N; i-- > 0;) x_r[i] = static_cast<PetscReal>(low_r[i]);
305:   #endif
306:       PetscCall(PetscFree(low[0]));
307:     } else {
308:       PetscCheck(PetscDefined(HAVE_CUDA) && PetscDefined(USE_REAL_DOUBLE), PetscObjectComm((PetscObject)ksp), PETSC_ERR_SUP, "CUDA in PETSc has no support for precisions other than single or double");
309:   #if PetscDefined(HAVE_CUDA)
310:     #if PetscDefined(HAVE_HPDDM)
311:       PetscCall(KSPSolve_HPDDM_CUDA_Private(data, b, x, n, PetscObjectComm((PetscObject)ksp)));
312:     #else
313:       SETERRQ(PetscObjectComm((PetscObject)ksp), PETSC_ERR_SUP, "No CUDA support with --download-hpddm from SLEPc");
314:     #endif
315:   #endif
316:     }
317: #else
318:     PetscCheck(data->precision != PETSC_PRECISION___FP16, PetscObjectComm((PetscObject)ksp), PETSC_ERR_SUP, "Reconfigure with --download-f2cblaslapack --with-f2cblaslapack-fp16-bindings");
319: #endif
320:   } else { /* Krylov basis stored in the same precision as PetscScalar */
321:     if (type == PETSC_MEMTYPE_HOST) PetscCall(HPDDM::IterativeMethod::solve(*data->op, b, x, n, PetscObjectComm((PetscObject)ksp)));
322:     else {
323:       PetscCheck(PetscDefined(USE_REAL_SINGLE) || PetscDefined(USE_REAL_DOUBLE), PetscObjectComm((PetscObject)ksp), PETSC_ERR_SUP, "CUDA in PETSc has no support for precisions other than single or double");
324: #if PetscDefined(HAVE_CUDA)
325:   #if PetscDefined(HAVE_HPDDM)
326:       PetscCall(KSPSolve_HPDDM_CUDA_Private(data, b, x, n, PetscObjectComm((PetscObject)ksp)));
327:   #else
328:       SETERRQ(PetscObjectComm((PetscObject)ksp), PETSC_ERR_SUP, "No CUDA support with --download-hpddm from SLEPc");
329:   #endif
330: #endif
331:     }
332:   }
333:   if (!ksp->reason) { /* KSPConvergedDefault() is still returning 0 (= KSP_CONVERGED_ITERATING) */
334:     if (ksp->its >= ksp->max_it) ksp->reason = KSP_DIVERGED_ITS;
335:     else ksp->reason = KSP_CONVERGED_RTOL; /* early exit by HPDDM, which only happens on breakdowns or convergence */
336:   }
337:   ksp->its = PetscMin(ksp->its, ksp->max_it);
338:   PetscFunctionReturn(PETSC_SUCCESS);
339: }

341: static PetscErrorCode KSPSolve_HPDDM(KSP ksp)
342: {
343:   KSP_HPDDM         *data = (KSP_HPDDM *)ksp->data;
344:   Mat                A, B;
345:   PetscScalar       *x, *bt = nullptr, **ptr;
346:   const PetscScalar *b;
347:   PetscInt           i, j, n;
348:   PetscBool          flg;
349:   PetscMemType       type[2];

351:   PetscFunctionBegin;
352:   PetscCall(PetscCitationsRegister(HPDDMCitation, &HPDDMCite));
353:   PetscCall(KSPGetOperators(ksp, &A, nullptr));
354:   PetscCall(PetscObjectTypeCompareAny((PetscObject)A, &flg, MATSEQKAIJ, MATMPIKAIJ, ""));
355:   PetscCall(VecGetArrayWriteAndMemType(ksp->vec_sol, &x, type));
356:   PetscCall(VecGetArrayReadAndMemType(ksp->vec_rhs, &b, type + 1));
357:   PetscCheck(type[0] == type[1], PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_INCOMP, "Right-hand side and solution vectors must have the same PetscMemType, %s != %s", PetscMemTypeToString(type[0]), PetscMemTypeToString(type[1]));
358:   if (!flg) {
359:     if (PetscMemTypeCUDA(type[0])) PetscCall(KSPSolve_HPDDM_Private<PETSC_MEMTYPE_CUDA>(ksp, b, x, 1));
360:     else {
361:       PetscCheck(PetscMemTypeHost(type[0]), PetscObjectComm((PetscObject)A), PETSC_ERR_SUP, "PetscMemType (%s) is neither PETSC_MEMTYPE_HOST nor PETSC_MEMTYPE_CUDA", PetscMemTypeToString(type[0]));
362:       PetscCall(KSPSolve_HPDDM_Private(ksp, b, x, 1));
363:     }
364:   } else {
365:     PetscCheck(PetscMemTypeHost(type[0]), PetscObjectComm((PetscObject)A), PETSC_ERR_SUP, "PetscMemType (%s) is not PETSC_MEMTYPE_HOST", PetscMemTypeToString(type[0]));
366:     PetscCall(MatKAIJGetScaledIdentity(A, &flg));
367:     PetscCall(MatKAIJGetAIJ(A, &B));
368:     PetscCall(MatGetBlockSize(A, &n));
369:     PetscCall(MatGetLocalSize(B, &i, nullptr));
370:     j = data->op->getDof();
371:     if (!flg) i *= n; /* S and T are not scaled identities, cannot use block methods */
372:     if (i != j) {     /* switching between block and standard methods */
373:       delete data->op;
374:       data->op = new HPDDM::PETScOperator(ksp, i);
375:     }
376:     if (flg && n > 1) {
377:       PetscCall(PetscMalloc1(i * n, &bt));
378:       /* from row- to column-major to be consistent with HPDDM */
379:       HPDDM::Wrapper<PetscScalar>::omatcopy<'T'>(i, n, b, n, bt, i);
380:       ptr = const_cast<PetscScalar **>(&b);
381:       std::swap(*ptr, bt);
382:       HPDDM::Wrapper<PetscScalar>::imatcopy<'T'>(i, n, x, n, i);
383:     }
384:     PetscCall(KSPSolve_HPDDM_Private(ksp, b, x, flg ? n : 1));
385:     if (flg && n > 1) {
386:       std::swap(*ptr, bt);
387:       PetscCall(PetscFree(bt));
388:       /* from column- to row-major to be consistent with MatKAIJ format */
389:       HPDDM::Wrapper<PetscScalar>::imatcopy<'T'>(n, i, x, i, n);
390:     }
391:   }
392:   PetscCall(VecRestoreArrayReadAndMemType(ksp->vec_rhs, &b));
393:   PetscCall(VecRestoreArrayWriteAndMemType(ksp->vec_sol, &x));
394:   PetscFunctionReturn(PETSC_SUCCESS);
395: }

397: /*@
398:   KSPHPDDMSetDeflationMat - Sets the deflation space used by Krylov methods in `KSPHPDDM` with recycling. This space is viewed as a set of vectors stored in
399:   a `MATDENSE` (column major).

401:   Input Parameters:
402: + ksp - iterative context
403: - U   - deflation space to be used during `KSPSolve()`

405:   Level: intermediate

407: .seealso: [](ch_ksp), `KSPHPDDM`, `KSPCreate()`, `KSPType`, `KSPHPDDMGetDeflationMat()`
408: @*/
409: PetscErrorCode KSPHPDDMSetDeflationMat(KSP ksp, Mat U)
410: {
411:   PetscFunctionBegin;
414:   PetscCheckSameComm(ksp, 1, U, 2);
415:   PetscUseMethod(ksp, "KSPHPDDMSetDeflationMat_C", (KSP, Mat), (ksp, U));
416:   PetscFunctionReturn(PETSC_SUCCESS);
417: }

419: /*@
420:   KSPHPDDMGetDeflationMat - Gets the deflation space computed by Krylov methods in `KSPHPDDM`  with recycling or `NULL` if `KSPSolve()` has not been called yet.

422:   Input Parameter:
423: . ksp - iterative context

425:   Output Parameter:
426: . U - deflation space generated during `KSPSolve()`

428:   Level: intermediate

430:   Note:
431:   This space is viewed as a set of vectors stored in a `MATDENSE` (column major). It is the responsibility of the user to free the returned `Mat`.

433: .seealso: [](ch_ksp), `KSPHPDDM`, `KSPCreate()`, `KSPType`, `KSPHPDDMSetDeflationMat()`
434: @*/
435: PetscErrorCode KSPHPDDMGetDeflationMat(KSP ksp, Mat *U)
436: {
437:   PetscFunctionBegin;
439:   if (U) {
440:     PetscAssertPointer(U, 2);
441:     PetscUseMethod(ksp, "KSPHPDDMGetDeflationMat_C", (KSP, Mat *), (ksp, U));
442:   }
443:   PetscFunctionReturn(PETSC_SUCCESS);
444: }

446: static PetscErrorCode KSPHPDDMSetDeflationMat_HPDDM(KSP ksp, Mat U)
447: {
448:   KSP_HPDDM            *data = (KSP_HPDDM *)ksp->data;
449:   HPDDM::PETScOperator *op   = data->op;
450:   Mat                   A;
451:   const PetscScalar    *array;
452:   PetscScalar          *copy;
453:   PetscInt              m1, M1, m2, M2, n2, N2, ldu;
454:   PetscBool             match;

456:   PetscFunctionBegin;
457:   if (!op) {
458:     PetscCall(KSPSetUp(ksp));
459:     op = data->op;
460:   }
461:   PetscCheck(data->precision == PETSC_SCALAR_PRECISION, PetscObjectComm((PetscObject)ksp), PETSC_ERR_SUP, "%s != %s", PetscPrecisionTypes[data->precision], PetscPrecisionTypes[PETSC_SCALAR_PRECISION]);
462:   PetscCall(KSPGetOperators(ksp, &A, nullptr));
463:   PetscCall(MatGetLocalSize(A, &m1, nullptr));
464:   PetscCall(MatGetLocalSize(U, &m2, &n2));
465:   PetscCall(MatGetSize(A, &M1, nullptr));
466:   PetscCall(MatGetSize(U, &M2, &N2));
467:   PetscCheck(m1 == m2 && M1 == M2, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Cannot use a deflation space with (m2,M2) = (%" PetscInt_FMT ",%" PetscInt_FMT ") for a linear system with (m1,M1) = (%" PetscInt_FMT ",%" PetscInt_FMT ")", m2, M2, m1, M1);
468:   PetscCall(PetscObjectTypeCompareAny((PetscObject)U, &match, MATSEQDENSE, MATMPIDENSE, ""));
469:   PetscCheck(match, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Provided deflation space not stored in a dense Mat");
470:   PetscCall(MatDenseGetArrayRead(U, &array));
471:   copy = op->allocate(m2, 1, N2);
472:   PetscCheck(copy, PETSC_COMM_SELF, PETSC_ERR_POINTER, "Memory allocation error");
473:   PetscCall(MatDenseGetLDA(U, &ldu));
474:   HPDDM::Wrapper<PetscScalar>::omatcopy<'N'>(N2, m2, array, ldu, copy, m2);
475:   PetscCall(MatDenseRestoreArrayRead(U, &array));
476:   PetscFunctionReturn(PETSC_SUCCESS);
477: }

479: static PetscErrorCode KSPHPDDMGetDeflationMat_HPDDM(KSP ksp, Mat *U)
480: {
481:   KSP_HPDDM            *data = (KSP_HPDDM *)ksp->data;
482:   HPDDM::PETScOperator *op   = data->op;
483:   Mat                   A;
484:   const PetscScalar    *array;
485:   PetscScalar          *copy;
486:   PetscInt              m1, M1, N2;

488:   PetscFunctionBegin;
489:   if (!op) {
490:     PetscCall(KSPSetUp(ksp));
491:     op = data->op;
492:   }
493:   PetscCheck(data->precision == PETSC_SCALAR_PRECISION, PetscObjectComm((PetscObject)ksp), PETSC_ERR_SUP, "%s != %s", PetscPrecisionTypes[data->precision], PetscPrecisionTypes[PETSC_SCALAR_PRECISION]);
494:   array = op->storage();
495:   N2    = op->k().first * op->k().second;
496:   if (!array) *U = nullptr;
497:   else {
498:     PetscCall(KSPGetOperators(ksp, &A, nullptr));
499:     PetscCall(MatGetLocalSize(A, &m1, nullptr));
500:     PetscCall(MatGetSize(A, &M1, nullptr));
501:     PetscCall(MatCreateDense(PetscObjectComm((PetscObject)ksp), m1, PETSC_DECIDE, M1, N2, nullptr, U));
502:     PetscCall(MatDenseGetArrayWrite(*U, &copy));
503:     PetscCall(PetscArraycpy(copy, array, m1 * N2));
504:     PetscCall(MatDenseRestoreArrayWrite(*U, &copy));
505:   }
506:   PetscFunctionReturn(PETSC_SUCCESS);
507: }

509: static PetscErrorCode KSPMatSolve_HPDDM(KSP ksp, Mat B, Mat X)
510: {
511:   KSP_HPDDM         *data = (KSP_HPDDM *)ksp->data;
512:   Mat                A;
513:   const PetscScalar *b;
514:   PetscScalar       *x;
515:   PetscInt           n, lda;
516:   PetscMemType       type[2];

518:   PetscFunctionBegin;
519:   PetscCall(PetscCitationsRegister(HPDDMCitation, &HPDDMCite));
520:   if (!data->op) PetscCall(KSPSetUp(ksp));
521:   PetscCall(KSPGetOperators(ksp, &A, nullptr));
522:   PetscCall(MatGetLocalSize(B, &n, nullptr));
523:   PetscCall(MatDenseGetLDA(B, &lda));
524:   PetscCheck(n == lda, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Unsupported leading dimension lda = %" PetscInt_FMT " with n = %" PetscInt_FMT, lda, n);
525:   PetscCall(MatGetLocalSize(A, &n, nullptr));
526:   PetscCall(MatDenseGetLDA(X, &lda));
527:   PetscCheck(n == lda, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Unsupported leading dimension lda = %" PetscInt_FMT " with n = %" PetscInt_FMT, lda, n);
528:   PetscCall(MatGetSize(X, nullptr, &n));
529:   PetscCall(MatDenseGetArrayWriteAndMemType(X, &x, type));
530:   PetscCall(MatDenseGetArrayReadAndMemType(B, &b, type + 1));
531:   PetscCheck(type[0] == type[1], PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_INCOMP, "Right-hand side and solution matrices must have the same PetscMemType, %s != %s", PetscMemTypeToString(type[0]), PetscMemTypeToString(type[1]));
532:   if (PetscMemTypeCUDA(type[0])) PetscCall(KSPSolve_HPDDM_Private<PETSC_MEMTYPE_CUDA>(ksp, b, x, n));
533:   else {
534:     PetscCheck(PetscMemTypeHost(type[0]), PetscObjectComm((PetscObject)A), PETSC_ERR_SUP, "PetscMemType (%s) is neither PETSC_MEMTYPE_HOST nor PETSC_MEMTYPE_CUDA", PetscMemTypeToString(type[0]));
535:     PetscCall(KSPSolve_HPDDM_Private(ksp, b, x, n));
536:   }
537:   PetscCall(MatDenseRestoreArrayReadAndMemType(B, &b));
538:   PetscCall(MatDenseRestoreArrayWriteAndMemType(X, &x));
539:   PetscFunctionReturn(PETSC_SUCCESS);
540: }

542: /*@
543:   KSPHPDDMSetType - Sets the type of Krylov method used in `KSPHPDDM`.

545:   Collective

547:   Input Parameters:
548: + ksp  - iterative context
549: - type - any of gmres, bgmres, cg, bcg, gcrodr, bgcrodr, bfbcg, or preonly

551:   Level: intermediate

553:   Notes:
554:   Unlike `KSPReset()`, this function does not destroy any deflation space attached to the `KSP`.

556:   As an example, in the following sequence\:
557: .vb
558:      KSPHPDDMSetType(ksp, KSPGCRODR);
559:      KSPSolve(ksp, b, x);
560:      KSPHPDDMSetType(ksp, KSPGMRES);
561:      KSPHPDDMSetType(ksp, KSPGCRODR);
562:      KSPSolve(ksp, b, x);
563: .ve
564:   the recycled space is reused in the second `KSPSolve()`.

566: .seealso: [](ch_ksp), `KSPCreate()`, `KSPType`, `KSPHPDDMType`, `KSPHPDDMGetType()`
567: @*/
568: PetscErrorCode KSPHPDDMSetType(KSP ksp, KSPHPDDMType type)
569: {
570:   PetscFunctionBegin;
573:   PetscUseMethod(ksp, "KSPHPDDMSetType_C", (KSP, KSPHPDDMType), (ksp, type));
574:   PetscFunctionReturn(PETSC_SUCCESS);
575: }

577: /*@
578:   KSPHPDDMGetType - Gets the type of Krylov method used in `KSPHPDDM`.

580:   Input Parameter:
581: . ksp - iterative context

583:   Output Parameter:
584: . type - any of gmres, bgmres, cg, bcg, gcrodr, bgcrodr, bfbcg, or preonly

586:   Level: intermediate

588: .seealso: [](ch_ksp), `KSPCreate()`, `KSPType`, `KSPHPDDMType`, `KSPHPDDMSetType()`
589: @*/
590: PetscErrorCode KSPHPDDMGetType(KSP ksp, KSPHPDDMType *type)
591: {
592:   PetscFunctionBegin;
594:   if (type) {
595:     PetscAssertPointer(type, 2);
596:     PetscUseMethod(ksp, "KSPHPDDMGetType_C", (KSP, KSPHPDDMType *), (ksp, type));
597:   }
598:   PetscFunctionReturn(PETSC_SUCCESS);
599: }

601: static PetscErrorCode KSPHPDDMSetType_HPDDM(KSP ksp, KSPHPDDMType type)
602: {
603:   KSP_HPDDM *data = (KSP_HPDDM *)ksp->data;
604:   PetscInt   i;
605:   PetscBool  flg = PETSC_FALSE;

607:   PetscFunctionBegin;
608:   for (i = 0; i < static_cast<PetscInt>(PETSC_STATIC_ARRAY_LENGTH(KSPHPDDMTypes)); ++i) {
609:     PetscCall(PetscStrcmp(KSPHPDDMTypes[type], KSPHPDDMTypes[i], &flg));
610:     if (flg) break;
611:   }
612:   PetscCheck(i != PETSC_STATIC_ARRAY_LENGTH(KSPHPDDMTypes), PetscObjectComm((PetscObject)ksp), PETSC_ERR_ARG_UNKNOWN_TYPE, "Unknown KSPHPDDMType %d", type);
613:   if (data->cntl[0] != static_cast<char>(PETSC_DECIDE) && data->cntl[0] != i) PetscCall(KSPReset_HPDDM_Private(ksp));
614:   data->cntl[0] = i;
615:   PetscFunctionReturn(PETSC_SUCCESS);
616: }

618: static PetscErrorCode KSPHPDDMGetType_HPDDM(KSP ksp, KSPHPDDMType *type)
619: {
620:   KSP_HPDDM *data = (KSP_HPDDM *)ksp->data;

622:   PetscFunctionBegin;
623:   PetscCheck(data->cntl[0] != static_cast<char>(PETSC_DECIDE), PETSC_COMM_SELF, PETSC_ERR_ORDER, "KSPHPDDMType not set yet");
624:   /* need to shift by -1 for HPDDM_KRYLOV_METHOD_NONE */
625:   *type = static_cast<KSPHPDDMType>(PetscMin(data->cntl[0], static_cast<char>(PETSC_STATIC_ARRAY_LENGTH(KSPHPDDMTypes) - 1)));
626:   PetscFunctionReturn(PETSC_SUCCESS);
627: }

629: /*MC
630:    KSPHPDDM - Interface with the HPDDM library. This `KSP` may be used to further select methods that are currently not implemented natively in PETSc, e.g.,
631:    GCRODR {cite}`parks2006recycling`, a recycled Krylov method which is similar to `KSPLGMRES`, see {cite}`jolivet2016block` for a comparison.
632:    ex75.c shows how to reproduce the results
633:    from the aforementioned paper {cite}`parks2006recycling`. A chronological bibliography of relevant publications linked with `KSP` available in HPDDM through `KSPHPDDM`,
634:    and not available directly in PETSc, may be found below. The interface is explained in details in {cite}`jolivetromanzampini2020`.
635:    See also {cite}`o1980block`, {cite}`ji2017breakdown` and {cite}`calandra2013modified`

637:    Options Database Keys:
638: +   -ksp_gmres_restart <restart, default=30>                  - see `KSPGMRES`
639: .   -ksp_hpddm_type <type, default=gmres>                     - any of gmres, bgmres, cg, bcg, gcrodr, bgcrodr, bfbcg, or preonly, see `KSPHPDDMType`
640: .   -ksp_hpddm_precision <value, default=same as PetscScalar> - any of __fp16, single, double or __float128, see `PetscPrecision`
641: .   -ksp_hpddm_deflation_tol <eps, default=\-1.0>             - tolerance when deflating right-hand sides inside block methods (no deflation by default,
642:                                                               only relevant with block methods)
643: .   -ksp_hpddm_enlarge_krylov_subspace <p, default=1>         - split the initial right-hand side into multiple vectors (only relevant with nonblock methods)
644: .   -ksp_hpddm_orthogonalization <type, default=cgs>          - any of cgs or mgs, see KSPGMRES
645: .   -ksp_hpddm_qr <type, default=cholqr>                      - distributed QR factorizations with any of cholqr, cgs, or mgs (only relevant with block methods)
646: .   -ksp_hpddm_variant <type, default=left>                   - any of left, right, or flexible (this option is superseded by `KSPSetPCSide()`)
647: .   -ksp_hpddm_recycle <n, default=0>                         - number of harmonic Ritz vectors to compute (only relevant with GCRODR or BGCRODR)
648: .   -ksp_hpddm_recycle_target <type, default=SM>              - criterion to select harmonic Ritz vectors using either SM, LM, SR, LR, SI, or LI
649:                                                               (only relevant with GCRODR or BGCRODR). For BGCRODR, if PETSc is compiled with SLEPc,
650:                                                               this option is not relevant, since SLEPc is used instead. Options are set with the prefix -ksp_hpddm_recycle_eps_
651: .   -ksp_hpddm_recycle_strategy <type, default=A>             - generalized eigenvalue problem A or B to solve for recycling (only relevant with flexible GCRODR or BGCRODR)
652: -   -ksp_hpddm_recycle_symmetric <true, default=false>        - symmetric generalized eigenproblems in BGCRODR, useful to switch to distributed solvers like
653:                                                               `EPSELEMENTAL` or `EPSSCALAPACK` (only relevant when PETSc is compiled with SLEPc)

655:    Level: intermediate

657: .seealso: [](ch_ksp), [](sec_flexibleksp), `KSPCreate()`, `KSPSetType()`, `KSPType`, `KSP`, `KSPGMRES`, `KSPCG`, `KSPLGMRES`, `KSPDGMRES`
658: M*/

660: PETSC_EXTERN PetscErrorCode KSPCreate_HPDDM(KSP ksp)
661: {
662:   KSP_HPDDM  *data;
663:   PetscInt    i;
664:   const char *common[] = {KSPGMRES, KSPCG, KSPPREONLY};
665:   PetscBool   flg      = PETSC_FALSE;

667:   PetscFunctionBegin;
668:   PetscCall(PetscNew(&data));
669:   ksp->data = (void *)data;
670:   PetscCall(KSPSetSupportedNorm(ksp, KSP_NORM_PRECONDITIONED, PC_LEFT, 2));
671:   PetscCall(KSPSetSupportedNorm(ksp, KSP_NORM_UNPRECONDITIONED, PC_RIGHT, 1));
672:   ksp->ops->solve          = KSPSolve_HPDDM;
673:   ksp->ops->matsolve       = KSPMatSolve_HPDDM;
674:   ksp->ops->setup          = KSPSetUp_HPDDM;
675:   ksp->ops->setfromoptions = KSPSetFromOptions_HPDDM;
676:   ksp->ops->destroy        = KSPDestroy_HPDDM;
677:   ksp->ops->view           = KSPView_HPDDM;
678:   ksp->ops->reset          = KSPReset_HPDDM;
679:   PetscCall(KSPReset_HPDDM_Private(ksp));
680:   for (i = 0; i < static_cast<PetscInt>(PETSC_STATIC_ARRAY_LENGTH(common)); ++i) {
681:     PetscCall(PetscStrcmp(((PetscObject)ksp)->type_name, common[i], &flg));
682:     if (flg) break;
683:   }
684:   if (!i) data->cntl[0] = HPDDM_KRYLOV_METHOD_GMRES;
685:   else if (i == 1) data->cntl[0] = HPDDM_KRYLOV_METHOD_CG;
686:   else if (i == 2) data->cntl[0] = HPDDM_KRYLOV_METHOD_NONE;
687:   if (data->cntl[0] != static_cast<char>(PETSC_DECIDE)) PetscCall(PetscInfo(ksp, "Using the previously set KSPType %s\n", common[i]));
688:   PetscCall(PetscObjectComposeFunction((PetscObject)ksp, "KSPHPDDMSetDeflationMat_C", KSPHPDDMSetDeflationMat_HPDDM));
689:   PetscCall(PetscObjectComposeFunction((PetscObject)ksp, "KSPHPDDMGetDeflationMat_C", KSPHPDDMGetDeflationMat_HPDDM));
690:   PetscCall(PetscObjectComposeFunction((PetscObject)ksp, "KSPHPDDMSetType_C", KSPHPDDMSetType_HPDDM));
691:   PetscCall(PetscObjectComposeFunction((PetscObject)ksp, "KSPHPDDMGetType_C", KSPHPDDMGetType_HPDDM));
692: #if PetscDefined(HAVE_SLEPC) && PetscDefined(HAVE_DYNAMIC_LIBRARIES) && PetscDefined(USE_SHARED_LIBRARIES)
693:   if (!loadedDL) PetscCall(HPDDMLoadDL_Private(&loadedDL));
694: #endif
695:   data->precision = PETSC_SCALAR_PRECISION;
696:   PetscFunctionReturn(PETSC_SUCCESS);
697: }