1 /* 2 This file defines an "generalized" additive Schwarz preconditioner for any Mat implementation. 3 In this version each MPI rank may intersect multiple subdomains and any subdomain may 4 intersect multiple MPI ranks. Intersections of subdomains with MPI ranks are called *local 5 subdomains*. 6 7 N - total number of distinct global subdomains (set explicitly in PCGASMSetTotalSubdomains() or implicitly PCGASMSetSubdomains() and then calculated in PCSetUp_GASM()) 8 n - actual number of local subdomains on this rank (set in PCGASMSetSubdomains() or calculated in PCGASMSetTotalSubdomains()) 9 nmax - maximum number of local subdomains per rank (calculated in PCSetUp_GASM()) 10 */ 11 #include <petsc/private/pcimpl.h> /*I "petscpc.h" I*/ 12 #include <petscdm.h> 13 14 typedef struct { 15 PetscInt N, n, nmax; 16 PetscInt overlap; /* overlap requested by user */ 17 PCGASMType type; /* use reduced interpolation, restriction or both */ 18 PetscBool type_set; /* if user set this value (so won't change it for symmetric problems) */ 19 PetscBool same_subdomain_solvers; /* flag indicating whether all local solvers are same */ 20 PetscBool sort_indices; /* flag to sort subdomain indices */ 21 PetscBool user_subdomains; /* whether the user set explicit subdomain index sets -- keep them on PCReset() */ 22 PetscBool dm_subdomains; /* whether DM is allowed to define subdomains */ 23 PetscBool hierarchicalpartitioning; 24 IS *ois; /* index sets that define the outer (conceptually, overlapping) subdomains */ 25 IS *iis; /* index sets that define the inner (conceptually, nonoverlapping) subdomains */ 26 KSP *ksp; /* linear solvers for each subdomain */ 27 Mat *pmat; /* subdomain block matrices */ 28 Vec gx, gy; /* Merged work vectors */ 29 Vec *x, *y; /* Split work vectors; storage aliases pieces of storage of the above merged vectors. */ 30 VecScatter gorestriction; /* merged restriction to disjoint union of outer subdomains */ 31 VecScatter girestriction; /* merged restriction to disjoint union of inner subdomains */ 32 VecScatter pctoouter; 33 IS permutationIS; 34 Mat permutationP; 35 Mat pcmat; 36 Vec pcx, pcy; 37 } PC_GASM; 38 39 static PetscErrorCode PCGASMComputeGlobalSubdomainNumbering_Private(PC pc, PetscInt **numbering, PetscInt **permutation) 40 { 41 PC_GASM *osm = (PC_GASM *)pc->data; 42 PetscInt i; 43 44 PetscFunctionBegin; 45 /* Determine the number of globally-distinct subdomains and compute a global numbering for them. */ 46 PetscCall(PetscMalloc2(osm->n, numbering, osm->n, permutation)); 47 PetscCall(PetscObjectsListGetGlobalNumbering(PetscObjectComm((PetscObject)pc), osm->n, (PetscObject *)osm->iis, NULL, *numbering)); 48 for (i = 0; i < osm->n; ++i) (*permutation)[i] = i; 49 PetscCall(PetscSortIntWithPermutation(osm->n, *numbering, *permutation)); 50 PetscFunctionReturn(PETSC_SUCCESS); 51 } 52 53 static PetscErrorCode PCGASMSubdomainView_Private(PC pc, PetscInt i, PetscViewer viewer) 54 { 55 PC_GASM *osm = (PC_GASM *)pc->data; 56 PetscInt j, nidx; 57 const PetscInt *idx; 58 PetscViewer sviewer; 59 char *cidx; 60 61 PetscFunctionBegin; 62 PetscCheck(i >= 0 && i < osm->n, PetscObjectComm((PetscObject)viewer), PETSC_ERR_ARG_WRONG, "Invalid subdomain %" PetscInt_FMT ": must nonnegative and less than %" PetscInt_FMT, i, osm->n); 63 /* Inner subdomains. */ 64 PetscCall(ISGetLocalSize(osm->iis[i], &nidx)); 65 /* 66 No more than 15 characters per index plus a space. 67 PetscViewerStringSPrintf requires a string of size at least 2, so use (nidx+1) instead of nidx, 68 in case nidx == 0. That will take care of the space for the trailing '\0' as well. 69 For nidx == 0, the whole string 16 '\0'. 70 */ 71 #define len 16 * (nidx + 1) + 1 72 PetscCall(PetscMalloc1(len, &cidx)); 73 PetscCall(PetscViewerStringOpen(PETSC_COMM_SELF, cidx, len, &sviewer)); 74 #undef len 75 PetscCall(ISGetIndices(osm->iis[i], &idx)); 76 for (j = 0; j < nidx; ++j) PetscCall(PetscViewerStringSPrintf(sviewer, "%" PetscInt_FMT " ", idx[j])); 77 PetscCall(ISRestoreIndices(osm->iis[i], &idx)); 78 PetscCall(PetscViewerDestroy(&sviewer)); 79 PetscCall(PetscViewerASCIIPrintf(viewer, "Inner subdomain:\n")); 80 PetscCall(PetscViewerFlush(viewer)); 81 PetscCall(PetscViewerASCIIPushSynchronized(viewer)); 82 PetscCall(PetscViewerASCIISynchronizedPrintf(viewer, "%s", cidx)); 83 PetscCall(PetscViewerFlush(viewer)); 84 PetscCall(PetscViewerASCIIPopSynchronized(viewer)); 85 PetscCall(PetscViewerASCIIPrintf(viewer, "\n")); 86 PetscCall(PetscViewerFlush(viewer)); 87 PetscCall(PetscFree(cidx)); 88 /* Outer subdomains. */ 89 PetscCall(ISGetLocalSize(osm->ois[i], &nidx)); 90 /* 91 No more than 15 characters per index plus a space. 92 PetscViewerStringSPrintf requires a string of size at least 2, so use (nidx+1) instead of nidx, 93 in case nidx == 0. That will take care of the space for the trailing '\0' as well. 94 For nidx == 0, the whole string 16 '\0'. 95 */ 96 #define len 16 * (nidx + 1) + 1 97 PetscCall(PetscMalloc1(len, &cidx)); 98 PetscCall(PetscViewerStringOpen(PETSC_COMM_SELF, cidx, len, &sviewer)); 99 #undef len 100 PetscCall(ISGetIndices(osm->ois[i], &idx)); 101 for (j = 0; j < nidx; ++j) PetscCall(PetscViewerStringSPrintf(sviewer, "%" PetscInt_FMT " ", idx[j])); 102 PetscCall(PetscViewerDestroy(&sviewer)); 103 PetscCall(ISRestoreIndices(osm->ois[i], &idx)); 104 PetscCall(PetscViewerASCIIPrintf(viewer, "Outer subdomain:\n")); 105 PetscCall(PetscViewerFlush(viewer)); 106 PetscCall(PetscViewerASCIIPushSynchronized(viewer)); 107 PetscCall(PetscViewerASCIISynchronizedPrintf(viewer, "%s", cidx)); 108 PetscCall(PetscViewerFlush(viewer)); 109 PetscCall(PetscViewerASCIIPopSynchronized(viewer)); 110 PetscCall(PetscViewerASCIIPrintf(viewer, "\n")); 111 PetscCall(PetscViewerFlush(viewer)); 112 PetscCall(PetscFree(cidx)); 113 PetscFunctionReturn(PETSC_SUCCESS); 114 } 115 116 static PetscErrorCode PCGASMPrintSubdomains(PC pc) 117 { 118 PC_GASM *osm = (PC_GASM *)pc->data; 119 const char *prefix; 120 char fname[PETSC_MAX_PATH_LEN + 1]; 121 PetscInt l, d, count; 122 PetscBool found; 123 PetscViewer viewer, sviewer = NULL; 124 PetscInt *numbering, *permutation; /* global numbering of locally-supported subdomains and the permutation from the local ordering */ 125 126 PetscFunctionBegin; 127 PetscCall(PCGetOptionsPrefix(pc, &prefix)); 128 PetscCall(PetscOptionsHasName(NULL, prefix, "-pc_gasm_print_subdomains", &found)); 129 if (!found) PetscFunctionReturn(PETSC_SUCCESS); 130 PetscCall(PetscOptionsGetString(NULL, prefix, "-pc_gasm_print_subdomains", fname, sizeof(fname), &found)); 131 if (!found) PetscCall(PetscStrncpy(fname, "stdout", sizeof(fname))); 132 PetscCall(PetscViewerASCIIOpen(PetscObjectComm((PetscObject)pc), fname, &viewer)); 133 /* 134 Make sure the viewer has a name. Otherwise this may cause a deadlock or other weird errors when creating a subcomm viewer: 135 the subcomm viewer will attempt to inherit the viewer's name, which, if not set, will be constructed collectively on the comm. 136 */ 137 PetscCall(PetscObjectName((PetscObject)viewer)); 138 l = 0; 139 PetscCall(PCGASMComputeGlobalSubdomainNumbering_Private(pc, &numbering, &permutation)); 140 for (count = 0; count < osm->N; ++count) { 141 /* Now let subdomains go one at a time in the global numbering order and print their subdomain/solver info. */ 142 if (l < osm->n) { 143 d = permutation[l]; /* d is the local number of the l-th smallest (in the global ordering) among the locally supported subdomains */ 144 if (numbering[d] == count) { 145 PetscCall(PetscViewerGetSubViewer(viewer, ((PetscObject)osm->ois[d])->comm, &sviewer)); 146 PetscCall(PCGASMSubdomainView_Private(pc, d, sviewer)); 147 PetscCall(PetscViewerRestoreSubViewer(viewer, ((PetscObject)osm->ois[d])->comm, &sviewer)); 148 ++l; 149 } 150 } 151 PetscCallMPI(MPI_Barrier(PetscObjectComm((PetscObject)pc))); 152 } 153 PetscCall(PetscFree2(numbering, permutation)); 154 PetscCall(PetscViewerDestroy(&viewer)); 155 PetscFunctionReturn(PETSC_SUCCESS); 156 } 157 158 static PetscErrorCode PCView_GASM(PC pc, PetscViewer viewer) 159 { 160 PC_GASM *osm = (PC_GASM *)pc->data; 161 const char *prefix; 162 PetscMPIInt rank, size; 163 PetscInt bsz; 164 PetscBool iascii, view_subdomains = PETSC_FALSE; 165 PetscViewer sviewer; 166 PetscInt count, l; 167 char overlap[256] = "user-defined overlap"; 168 char gsubdomains[256] = "unknown total number of subdomains"; 169 char msubdomains[256] = "unknown max number of local subdomains"; 170 PetscInt *numbering, *permutation; /* global numbering of locally-supported subdomains and the permutation from the local ordering */ 171 172 PetscFunctionBegin; 173 PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)pc), &size)); 174 PetscCallMPI(MPI_Comm_rank(PetscObjectComm((PetscObject)pc), &rank)); 175 176 if (osm->overlap >= 0) PetscCall(PetscSNPrintf(overlap, sizeof(overlap), "requested amount of overlap = %" PetscInt_FMT, osm->overlap)); 177 if (osm->N != PETSC_DETERMINE) PetscCall(PetscSNPrintf(gsubdomains, sizeof(gsubdomains), "total number of subdomains = %" PetscInt_FMT, osm->N)); 178 if (osm->nmax != PETSC_DETERMINE) PetscCall(PetscSNPrintf(msubdomains, sizeof(msubdomains), "max number of local subdomains = %" PetscInt_FMT, osm->nmax)); 179 180 PetscCall(PCGetOptionsPrefix(pc, &prefix)); 181 PetscCall(PetscOptionsGetBool(NULL, prefix, "-pc_gasm_view_subdomains", &view_subdomains, NULL)); 182 183 PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERASCII, &iascii)); 184 if (iascii) { 185 /* 186 Make sure the viewer has a name. Otherwise this may cause a deadlock when creating a subcomm viewer: 187 the subcomm viewer will attempt to inherit the viewer's name, which, if not set, will be constructed 188 collectively on the comm. 189 */ 190 PetscCall(PetscObjectName((PetscObject)viewer)); 191 PetscCall(PetscViewerASCIIPrintf(viewer, " Restriction/interpolation type: %s\n", PCGASMTypes[osm->type])); 192 PetscCall(PetscViewerASCIIPrintf(viewer, " %s\n", overlap)); 193 PetscCall(PetscViewerASCIIPrintf(viewer, " %s\n", gsubdomains)); 194 PetscCall(PetscViewerASCIIPrintf(viewer, " %s\n", msubdomains)); 195 PetscCall(PetscViewerASCIIPushSynchronized(viewer)); 196 PetscCall(PetscViewerASCIISynchronizedPrintf(viewer, " [%d|%d] number of locally-supported subdomains = %" PetscInt_FMT "\n", rank, size, osm->n)); 197 PetscCall(PetscViewerFlush(viewer)); 198 PetscCall(PetscViewerASCIIPopSynchronized(viewer)); 199 /* Cannot take advantage of osm->same_subdomain_solvers without a global numbering of subdomains. */ 200 PetscCall(PetscViewerASCIIPrintf(viewer, " Subdomain solver info is as follows:\n")); 201 PetscCall(PetscViewerASCIIPushTab(viewer)); 202 PetscCall(PetscViewerASCIIPrintf(viewer, " - - - - - - - - - - - - - - - - - -\n")); 203 /* Make sure that everybody waits for the banner to be printed. */ 204 PetscCallMPI(MPI_Barrier(PetscObjectComm((PetscObject)viewer))); 205 /* Now let subdomains go one at a time in the global numbering order and print their subdomain/solver info. */ 206 PetscCall(PCGASMComputeGlobalSubdomainNumbering_Private(pc, &numbering, &permutation)); 207 l = 0; 208 for (count = 0; count < osm->N; ++count) { 209 PetscMPIInt srank, ssize; 210 if (l < osm->n) { 211 PetscInt d = permutation[l]; /* d is the local number of the l-th smallest (in the global ordering) among the locally supported subdomains */ 212 if (numbering[d] == count) { 213 PetscCallMPI(MPI_Comm_size(((PetscObject)osm->ois[d])->comm, &ssize)); 214 PetscCallMPI(MPI_Comm_rank(((PetscObject)osm->ois[d])->comm, &srank)); 215 PetscCall(PetscViewerGetSubViewer(viewer, ((PetscObject)osm->ois[d])->comm, &sviewer)); 216 PetscCall(ISGetLocalSize(osm->ois[d], &bsz)); 217 PetscCall(PetscViewerASCIISynchronizedPrintf(sviewer, " [%d|%d] (subcomm [%d|%d]) local subdomain number %" PetscInt_FMT ", local size = %" PetscInt_FMT "\n", rank, size, srank, ssize, d, bsz)); 218 PetscCall(PetscViewerFlush(sviewer)); 219 if (view_subdomains) PetscCall(PCGASMSubdomainView_Private(pc, d, sviewer)); 220 if (!pc->setupcalled) { 221 PetscCall(PetscViewerASCIIPrintf(sviewer, " Solver not set up yet: PCSetUp() not yet called\n")); 222 } else { 223 PetscCall(KSPView(osm->ksp[d], sviewer)); 224 } 225 PetscCall(PetscViewerASCIIPrintf(sviewer, " - - - - - - - - - - - - - - - - - -\n")); 226 PetscCall(PetscViewerFlush(sviewer)); 227 PetscCall(PetscViewerRestoreSubViewer(viewer, ((PetscObject)osm->ois[d])->comm, &sviewer)); 228 ++l; 229 } 230 } 231 PetscCallMPI(MPI_Barrier(PetscObjectComm((PetscObject)pc))); 232 } 233 PetscCall(PetscFree2(numbering, permutation)); 234 PetscCall(PetscViewerASCIIPopTab(viewer)); 235 PetscCall(PetscViewerFlush(viewer)); 236 /* this line is needed to match the extra PetscViewerASCIIPushSynchronized() in PetscViewerGetSubViewer() */ 237 PetscCall(PetscViewerASCIIPopSynchronized(viewer)); 238 } 239 PetscFunctionReturn(PETSC_SUCCESS); 240 } 241 242 PETSC_INTERN PetscErrorCode PCGASMCreateLocalSubdomains(Mat A, PetscInt nloc, IS *iis[]); 243 244 PetscErrorCode PCGASMSetHierarchicalPartitioning(PC pc) 245 { 246 PC_GASM *osm = (PC_GASM *)pc->data; 247 MatPartitioning part; 248 MPI_Comm comm; 249 PetscMPIInt size; 250 PetscInt nlocalsubdomains, fromrows_localsize; 251 IS partitioning, fromrows, isn; 252 Vec outervec; 253 254 PetscFunctionBegin; 255 PetscCall(PetscObjectGetComm((PetscObject)pc, &comm)); 256 PetscCallMPI(MPI_Comm_size(comm, &size)); 257 /* we do not need a hierarchical partitioning when 258 * the total number of subdomains is consistent with 259 * the number of MPI tasks. 260 * For the following cases, we do not need to use HP 261 * */ 262 if (osm->N == PETSC_DETERMINE || osm->N >= size || osm->N == 1) PetscFunctionReturn(PETSC_SUCCESS); 263 PetscCheck(size % osm->N == 0, PETSC_COMM_WORLD, PETSC_ERR_ARG_INCOMP, "have to specify the total number of subdomains %" PetscInt_FMT " to be a factor of the number of ranks %d ", osm->N, size); 264 nlocalsubdomains = size / osm->N; 265 osm->n = 1; 266 PetscCall(MatPartitioningCreate(comm, &part)); 267 PetscCall(MatPartitioningSetAdjacency(part, pc->pmat)); 268 PetscCall(MatPartitioningSetType(part, MATPARTITIONINGHIERARCH)); 269 PetscCall(MatPartitioningHierarchicalSetNcoarseparts(part, osm->N)); 270 PetscCall(MatPartitioningHierarchicalSetNfineparts(part, nlocalsubdomains)); 271 PetscCall(MatPartitioningSetFromOptions(part)); 272 /* get new rank owner number of each vertex */ 273 PetscCall(MatPartitioningApply(part, &partitioning)); 274 PetscCall(ISBuildTwoSided(partitioning, NULL, &fromrows)); 275 PetscCall(ISPartitioningToNumbering(partitioning, &isn)); 276 PetscCall(ISDestroy(&isn)); 277 PetscCall(ISGetLocalSize(fromrows, &fromrows_localsize)); 278 PetscCall(MatPartitioningDestroy(&part)); 279 PetscCall(MatCreateVecs(pc->pmat, &outervec, NULL)); 280 PetscCall(VecCreateMPI(comm, fromrows_localsize, PETSC_DETERMINE, &(osm->pcx))); 281 PetscCall(VecDuplicate(osm->pcx, &(osm->pcy))); 282 PetscCall(VecScatterCreate(osm->pcx, NULL, outervec, fromrows, &(osm->pctoouter))); 283 PetscCall(MatCreateSubMatrix(pc->pmat, fromrows, fromrows, MAT_INITIAL_MATRIX, &(osm->permutationP))); 284 PetscCall(PetscObjectReference((PetscObject)fromrows)); 285 osm->permutationIS = fromrows; 286 osm->pcmat = pc->pmat; 287 PetscCall(PetscObjectReference((PetscObject)osm->permutationP)); 288 pc->pmat = osm->permutationP; 289 PetscCall(VecDestroy(&outervec)); 290 PetscCall(ISDestroy(&fromrows)); 291 PetscCall(ISDestroy(&partitioning)); 292 osm->n = PETSC_DETERMINE; 293 PetscFunctionReturn(PETSC_SUCCESS); 294 } 295 296 static PetscErrorCode PCSetUp_GASM(PC pc) 297 { 298 PC_GASM *osm = (PC_GASM *)pc->data; 299 PetscInt i, nInnerIndices, nTotalInnerIndices; 300 PetscMPIInt rank, size; 301 MatReuse scall = MAT_REUSE_MATRIX; 302 KSP ksp; 303 PC subpc; 304 const char *prefix, *pprefix; 305 Vec x, y; 306 PetscInt oni; /* Number of indices in the i-th local outer subdomain. */ 307 const PetscInt *oidxi; /* Indices from the i-th subdomain local outer subdomain. */ 308 PetscInt on; /* Number of indices in the disjoint union of local outer subdomains. */ 309 PetscInt *oidx; /* Indices in the disjoint union of local outer subdomains. */ 310 IS gois; /* Disjoint union the global indices of outer subdomains. */ 311 IS goid; /* Identity IS of the size of the disjoint union of outer subdomains. */ 312 PetscScalar *gxarray, *gyarray; 313 PetscInt gostart; /* Start of locally-owned indices in the vectors -- osm->gx,osm->gy -- over the disjoint union of outer subdomains. */ 314 PetscInt num_subdomains = 0; 315 DM *subdomain_dm = NULL; 316 char **subdomain_names = NULL; 317 PetscInt *numbering; 318 319 PetscFunctionBegin; 320 PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)pc), &size)); 321 PetscCallMPI(MPI_Comm_rank(PetscObjectComm((PetscObject)pc), &rank)); 322 if (!pc->setupcalled) { 323 /* use a hierarchical partitioning */ 324 if (osm->hierarchicalpartitioning) PetscCall(PCGASMSetHierarchicalPartitioning(pc)); 325 if (osm->n == PETSC_DETERMINE) { 326 if (osm->N != PETSC_DETERMINE) { 327 /* No local subdomains given, but the desired number of total subdomains is known, so construct them accordingly. */ 328 PetscCall(PCGASMCreateSubdomains(pc->pmat, osm->N, &osm->n, &osm->iis)); 329 } else if (osm->dm_subdomains && pc->dm) { 330 /* try pc->dm next, if allowed */ 331 PetscInt d; 332 IS *inner_subdomain_is, *outer_subdomain_is; 333 PetscCall(DMCreateDomainDecomposition(pc->dm, &num_subdomains, &subdomain_names, &inner_subdomain_is, &outer_subdomain_is, &subdomain_dm)); 334 if (num_subdomains) PetscCall(PCGASMSetSubdomains(pc, num_subdomains, inner_subdomain_is, outer_subdomain_is)); 335 for (d = 0; d < num_subdomains; ++d) { 336 if (inner_subdomain_is) PetscCall(ISDestroy(&inner_subdomain_is[d])); 337 if (outer_subdomain_is) PetscCall(ISDestroy(&outer_subdomain_is[d])); 338 } 339 PetscCall(PetscFree(inner_subdomain_is)); 340 PetscCall(PetscFree(outer_subdomain_is)); 341 } else { 342 /* still no subdomains; use one per rank */ 343 osm->nmax = osm->n = 1; 344 PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)pc), &size)); 345 osm->N = size; 346 PetscCall(PCGASMCreateLocalSubdomains(pc->pmat, osm->n, &osm->iis)); 347 } 348 } 349 if (!osm->iis) { 350 /* 351 osm->n was set in PCGASMSetSubdomains(), but the actual subdomains have not been supplied. 352 We create the requisite number of local inner subdomains and then expand them into 353 out subdomains, if necessary. 354 */ 355 PetscCall(PCGASMCreateLocalSubdomains(pc->pmat, osm->n, &osm->iis)); 356 } 357 if (!osm->ois) { 358 /* 359 Initially make outer subdomains the same as inner subdomains. If nonzero additional overlap 360 has been requested, copy the inner subdomains over so they can be modified. 361 */ 362 PetscCall(PetscMalloc1(osm->n, &osm->ois)); 363 for (i = 0; i < osm->n; ++i) { 364 if (osm->overlap > 0 && osm->N > 1) { /* With positive overlap, osm->iis[i] will be modified */ 365 PetscCall(ISDuplicate(osm->iis[i], (osm->ois) + i)); 366 PetscCall(ISCopy(osm->iis[i], osm->ois[i])); 367 } else { 368 PetscCall(PetscObjectReference((PetscObject)((osm->iis)[i]))); 369 osm->ois[i] = osm->iis[i]; 370 } 371 } 372 if (osm->overlap > 0 && osm->N > 1) { 373 /* Extend the "overlapping" regions by a number of steps */ 374 PetscCall(MatIncreaseOverlapSplit(pc->pmat, osm->n, osm->ois, osm->overlap)); 375 } 376 } 377 378 /* Now the subdomains are defined. Determine their global and max local numbers, if necessary. */ 379 if (osm->nmax == PETSC_DETERMINE) { 380 PetscMPIInt inwork, outwork; 381 /* determine global number of subdomains and the max number of local subdomains */ 382 inwork = osm->n; 383 PetscCall(MPIU_Allreduce(&inwork, &outwork, 1, MPI_INT, MPI_MAX, PetscObjectComm((PetscObject)pc))); 384 osm->nmax = outwork; 385 } 386 if (osm->N == PETSC_DETERMINE) { 387 /* Determine the number of globally-distinct subdomains and compute a global numbering for them. */ 388 PetscCall(PetscObjectsListGetGlobalNumbering(PetscObjectComm((PetscObject)pc), osm->n, (PetscObject *)osm->ois, &osm->N, NULL)); 389 } 390 391 if (osm->sort_indices) { 392 for (i = 0; i < osm->n; i++) { 393 PetscCall(ISSort(osm->ois[i])); 394 PetscCall(ISSort(osm->iis[i])); 395 } 396 } 397 PetscCall(PCGetOptionsPrefix(pc, &prefix)); 398 PetscCall(PCGASMPrintSubdomains(pc)); 399 400 /* 401 Merge the ISs, create merged vectors and restrictions. 402 */ 403 /* Merge outer subdomain ISs and construct a restriction onto the disjoint union of local outer subdomains. */ 404 on = 0; 405 for (i = 0; i < osm->n; i++) { 406 PetscCall(ISGetLocalSize(osm->ois[i], &oni)); 407 on += oni; 408 } 409 PetscCall(PetscMalloc1(on, &oidx)); 410 on = 0; 411 /* Merge local indices together */ 412 for (i = 0; i < osm->n; i++) { 413 PetscCall(ISGetLocalSize(osm->ois[i], &oni)); 414 PetscCall(ISGetIndices(osm->ois[i], &oidxi)); 415 PetscCall(PetscArraycpy(oidx + on, oidxi, oni)); 416 PetscCall(ISRestoreIndices(osm->ois[i], &oidxi)); 417 on += oni; 418 } 419 PetscCall(ISCreateGeneral(((PetscObject)(pc))->comm, on, oidx, PETSC_OWN_POINTER, &gois)); 420 nTotalInnerIndices = 0; 421 for (i = 0; i < osm->n; i++) { 422 PetscCall(ISGetLocalSize(osm->iis[i], &nInnerIndices)); 423 nTotalInnerIndices += nInnerIndices; 424 } 425 PetscCall(VecCreateMPI(((PetscObject)(pc))->comm, nTotalInnerIndices, PETSC_DETERMINE, &x)); 426 PetscCall(VecDuplicate(x, &y)); 427 428 PetscCall(VecCreateMPI(PetscObjectComm((PetscObject)pc), on, PETSC_DECIDE, &osm->gx)); 429 PetscCall(VecDuplicate(osm->gx, &osm->gy)); 430 PetscCall(VecGetOwnershipRange(osm->gx, &gostart, NULL)); 431 PetscCall(ISCreateStride(PetscObjectComm((PetscObject)pc), on, gostart, 1, &goid)); 432 /* gois might indices not on local */ 433 PetscCall(VecScatterCreate(x, gois, osm->gx, goid, &(osm->gorestriction))); 434 PetscCall(PetscMalloc1(osm->n, &numbering)); 435 PetscCall(PetscObjectsListGetGlobalNumbering(PetscObjectComm((PetscObject)pc), osm->n, (PetscObject *)osm->ois, NULL, numbering)); 436 PetscCall(VecDestroy(&x)); 437 PetscCall(ISDestroy(&gois)); 438 439 /* Merge inner subdomain ISs and construct a restriction onto the disjoint union of local inner subdomains. */ 440 { 441 PetscInt ini; /* Number of indices the i-th a local inner subdomain. */ 442 PetscInt in; /* Number of indices in the disjoint union of local inner subdomains. */ 443 PetscInt *iidx; /* Global indices in the merged local inner subdomain. */ 444 PetscInt *ioidx; /* Global indices of the disjoint union of inner subdomains within the disjoint union of outer subdomains. */ 445 IS giis; /* IS for the disjoint union of inner subdomains. */ 446 IS giois; /* IS for the disjoint union of inner subdomains within the disjoint union of outer subdomains. */ 447 PetscScalar *array; 448 const PetscInt *indices; 449 PetscInt k; 450 on = 0; 451 for (i = 0; i < osm->n; i++) { 452 PetscCall(ISGetLocalSize(osm->ois[i], &oni)); 453 on += oni; 454 } 455 PetscCall(PetscMalloc1(on, &iidx)); 456 PetscCall(PetscMalloc1(on, &ioidx)); 457 PetscCall(VecGetArray(y, &array)); 458 /* set communicator id to determine where overlap is */ 459 in = 0; 460 for (i = 0; i < osm->n; i++) { 461 PetscCall(ISGetLocalSize(osm->iis[i], &ini)); 462 for (k = 0; k < ini; ++k) array[in + k] = numbering[i]; 463 in += ini; 464 } 465 PetscCall(VecRestoreArray(y, &array)); 466 PetscCall(VecScatterBegin(osm->gorestriction, y, osm->gy, INSERT_VALUES, SCATTER_FORWARD)); 467 PetscCall(VecScatterEnd(osm->gorestriction, y, osm->gy, INSERT_VALUES, SCATTER_FORWARD)); 468 PetscCall(VecGetOwnershipRange(osm->gy, &gostart, NULL)); 469 PetscCall(VecGetArray(osm->gy, &array)); 470 on = 0; 471 in = 0; 472 for (i = 0; i < osm->n; i++) { 473 PetscCall(ISGetLocalSize(osm->ois[i], &oni)); 474 PetscCall(ISGetIndices(osm->ois[i], &indices)); 475 for (k = 0; k < oni; k++) { 476 /* skip overlapping indices to get inner domain */ 477 if (PetscRealPart(array[on + k]) != numbering[i]) continue; 478 iidx[in] = indices[k]; 479 ioidx[in++] = gostart + on + k; 480 } 481 PetscCall(ISRestoreIndices(osm->ois[i], &indices)); 482 on += oni; 483 } 484 PetscCall(VecRestoreArray(osm->gy, &array)); 485 PetscCall(ISCreateGeneral(PetscObjectComm((PetscObject)pc), in, iidx, PETSC_OWN_POINTER, &giis)); 486 PetscCall(ISCreateGeneral(PetscObjectComm((PetscObject)pc), in, ioidx, PETSC_OWN_POINTER, &giois)); 487 PetscCall(VecScatterCreate(y, giis, osm->gy, giois, &osm->girestriction)); 488 PetscCall(VecDestroy(&y)); 489 PetscCall(ISDestroy(&giis)); 490 PetscCall(ISDestroy(&giois)); 491 } 492 PetscCall(ISDestroy(&goid)); 493 PetscCall(PetscFree(numbering)); 494 495 /* Create the subdomain work vectors. */ 496 PetscCall(PetscMalloc1(osm->n, &osm->x)); 497 PetscCall(PetscMalloc1(osm->n, &osm->y)); 498 PetscCall(VecGetArray(osm->gx, &gxarray)); 499 PetscCall(VecGetArray(osm->gy, &gyarray)); 500 for (i = 0, on = 0; i < osm->n; ++i, on += oni) { 501 PetscInt oNi; 502 PetscCall(ISGetLocalSize(osm->ois[i], &oni)); 503 /* on a sub communicator */ 504 PetscCall(ISGetSize(osm->ois[i], &oNi)); 505 PetscCall(VecCreateMPIWithArray(((PetscObject)(osm->ois[i]))->comm, 1, oni, oNi, gxarray + on, &osm->x[i])); 506 PetscCall(VecCreateMPIWithArray(((PetscObject)(osm->ois[i]))->comm, 1, oni, oNi, gyarray + on, &osm->y[i])); 507 } 508 PetscCall(VecRestoreArray(osm->gx, &gxarray)); 509 PetscCall(VecRestoreArray(osm->gy, &gyarray)); 510 /* Create the subdomain solvers */ 511 PetscCall(PetscMalloc1(osm->n, &osm->ksp)); 512 for (i = 0; i < osm->n; i++) { 513 char subprefix[PETSC_MAX_PATH_LEN + 1]; 514 PetscCall(KSPCreate(((PetscObject)(osm->ois[i]))->comm, &ksp)); 515 PetscCall(KSPSetErrorIfNotConverged(ksp, pc->erroriffailure)); 516 PetscCall(PetscObjectIncrementTabLevel((PetscObject)ksp, (PetscObject)pc, 1)); 517 PetscCall(KSPSetType(ksp, KSPPREONLY)); 518 PetscCall(KSPGetPC(ksp, &subpc)); /* Why do we need this here? */ 519 if (subdomain_dm) { 520 PetscCall(KSPSetDM(ksp, subdomain_dm[i])); 521 PetscCall(DMDestroy(subdomain_dm + i)); 522 } 523 PetscCall(PCGetOptionsPrefix(pc, &prefix)); 524 PetscCall(KSPSetOptionsPrefix(ksp, prefix)); 525 if (subdomain_names && subdomain_names[i]) { 526 PetscCall(PetscSNPrintf(subprefix, PETSC_MAX_PATH_LEN, "sub_%s_", subdomain_names[i])); 527 PetscCall(KSPAppendOptionsPrefix(ksp, subprefix)); 528 PetscCall(PetscFree(subdomain_names[i])); 529 } 530 PetscCall(KSPAppendOptionsPrefix(ksp, "sub_")); 531 osm->ksp[i] = ksp; 532 } 533 PetscCall(PetscFree(subdomain_dm)); 534 PetscCall(PetscFree(subdomain_names)); 535 scall = MAT_INITIAL_MATRIX; 536 } else { /* if (pc->setupcalled) */ 537 /* 538 Destroy the submatrices from the previous iteration 539 */ 540 if (pc->flag == DIFFERENT_NONZERO_PATTERN) { 541 PetscCall(MatDestroyMatrices(osm->n, &osm->pmat)); 542 scall = MAT_INITIAL_MATRIX; 543 } 544 if (osm->permutationIS) { 545 PetscCall(MatCreateSubMatrix(pc->pmat, osm->permutationIS, osm->permutationIS, scall, &osm->permutationP)); 546 PetscCall(PetscObjectReference((PetscObject)osm->permutationP)); 547 osm->pcmat = pc->pmat; 548 pc->pmat = osm->permutationP; 549 } 550 } 551 552 /* 553 Extract the submatrices. 554 */ 555 if (size > 1) { 556 PetscCall(MatCreateSubMatricesMPI(pc->pmat, osm->n, osm->ois, osm->ois, scall, &osm->pmat)); 557 } else { 558 PetscCall(MatCreateSubMatrices(pc->pmat, osm->n, osm->ois, osm->ois, scall, &osm->pmat)); 559 } 560 if (scall == MAT_INITIAL_MATRIX) { 561 PetscCall(PetscObjectGetOptionsPrefix((PetscObject)pc->pmat, &pprefix)); 562 for (i = 0; i < osm->n; i++) PetscCall(PetscObjectSetOptionsPrefix((PetscObject)osm->pmat[i], pprefix)); 563 } 564 565 /* Return control to the user so that the submatrices can be modified (e.g., to apply 566 different boundary conditions for the submatrices than for the global problem) */ 567 PetscCall(PCModifySubMatrices(pc, osm->n, osm->ois, osm->ois, osm->pmat, pc->modifysubmatricesP)); 568 569 /* 570 Loop over submatrices putting them into local ksps 571 */ 572 for (i = 0; i < osm->n; i++) { 573 PetscCall(KSPSetOperators(osm->ksp[i], osm->pmat[i], osm->pmat[i])); 574 PetscCall(KSPGetOptionsPrefix(osm->ksp[i], &prefix)); 575 PetscCall(MatSetOptionsPrefix(osm->pmat[i], prefix)); 576 if (!pc->setupcalled) PetscCall(KSPSetFromOptions(osm->ksp[i])); 577 } 578 if (osm->pcmat) { 579 PetscCall(MatDestroy(&pc->pmat)); 580 pc->pmat = osm->pcmat; 581 osm->pcmat = NULL; 582 } 583 PetscFunctionReturn(PETSC_SUCCESS); 584 } 585 586 static PetscErrorCode PCSetUpOnBlocks_GASM(PC pc) 587 { 588 PC_GASM *osm = (PC_GASM *)pc->data; 589 PetscInt i; 590 591 PetscFunctionBegin; 592 for (i = 0; i < osm->n; i++) PetscCall(KSPSetUp(osm->ksp[i])); 593 PetscFunctionReturn(PETSC_SUCCESS); 594 } 595 596 static PetscErrorCode PCApply_GASM(PC pc, Vec xin, Vec yout) 597 { 598 PC_GASM *osm = (PC_GASM *)pc->data; 599 PetscInt i; 600 Vec x, y; 601 ScatterMode forward = SCATTER_FORWARD, reverse = SCATTER_REVERSE; 602 603 PetscFunctionBegin; 604 if (osm->pctoouter) { 605 PetscCall(VecScatterBegin(osm->pctoouter, xin, osm->pcx, INSERT_VALUES, SCATTER_REVERSE)); 606 PetscCall(VecScatterEnd(osm->pctoouter, xin, osm->pcx, INSERT_VALUES, SCATTER_REVERSE)); 607 x = osm->pcx; 608 y = osm->pcy; 609 } else { 610 x = xin; 611 y = yout; 612 } 613 /* 614 support for limiting the restriction or interpolation only to the inner 615 subdomain values (leaving the other values 0). 616 */ 617 if (!(osm->type & PC_GASM_RESTRICT)) { 618 /* have to zero the work RHS since scatter may leave some slots empty */ 619 PetscCall(VecZeroEntries(osm->gx)); 620 PetscCall(VecScatterBegin(osm->girestriction, x, osm->gx, INSERT_VALUES, forward)); 621 } else { 622 PetscCall(VecScatterBegin(osm->gorestriction, x, osm->gx, INSERT_VALUES, forward)); 623 } 624 PetscCall(VecZeroEntries(osm->gy)); 625 if (!(osm->type & PC_GASM_RESTRICT)) { 626 PetscCall(VecScatterEnd(osm->girestriction, x, osm->gx, INSERT_VALUES, forward)); 627 } else { 628 PetscCall(VecScatterEnd(osm->gorestriction, x, osm->gx, INSERT_VALUES, forward)); 629 } 630 /* do the subdomain solves */ 631 for (i = 0; i < osm->n; ++i) { 632 PetscCall(KSPSolve(osm->ksp[i], osm->x[i], osm->y[i])); 633 PetscCall(KSPCheckSolve(osm->ksp[i], pc, osm->y[i])); 634 } 635 /* do we need to zero y? */ 636 PetscCall(VecZeroEntries(y)); 637 if (!(osm->type & PC_GASM_INTERPOLATE)) { 638 PetscCall(VecScatterBegin(osm->girestriction, osm->gy, y, ADD_VALUES, reverse)); 639 PetscCall(VecScatterEnd(osm->girestriction, osm->gy, y, ADD_VALUES, reverse)); 640 } else { 641 PetscCall(VecScatterBegin(osm->gorestriction, osm->gy, y, ADD_VALUES, reverse)); 642 PetscCall(VecScatterEnd(osm->gorestriction, osm->gy, y, ADD_VALUES, reverse)); 643 } 644 if (osm->pctoouter) { 645 PetscCall(VecScatterBegin(osm->pctoouter, y, yout, INSERT_VALUES, SCATTER_FORWARD)); 646 PetscCall(VecScatterEnd(osm->pctoouter, y, yout, INSERT_VALUES, SCATTER_FORWARD)); 647 } 648 PetscFunctionReturn(PETSC_SUCCESS); 649 } 650 651 static PetscErrorCode PCMatApply_GASM(PC pc, Mat Xin, Mat Yout) 652 { 653 PC_GASM *osm = (PC_GASM *)pc->data; 654 Mat X, Y, O = NULL, Z, W; 655 Vec x, y; 656 PetscInt i, m, M, N; 657 ScatterMode forward = SCATTER_FORWARD, reverse = SCATTER_REVERSE; 658 659 PetscFunctionBegin; 660 PetscCheck(osm->n == 1, PetscObjectComm((PetscObject)pc), PETSC_ERR_SUP, "Not yet implemented"); 661 PetscCall(MatGetSize(Xin, NULL, &N)); 662 if (osm->pctoouter) { 663 PetscCall(VecGetLocalSize(osm->pcx, &m)); 664 PetscCall(VecGetSize(osm->pcx, &M)); 665 PetscCall(MatCreateDense(PetscObjectComm((PetscObject)osm->ois[0]), m, PETSC_DECIDE, M, N, NULL, &O)); 666 for (i = 0; i < N; ++i) { 667 PetscCall(MatDenseGetColumnVecRead(Xin, i, &x)); 668 PetscCall(MatDenseGetColumnVecWrite(O, i, &y)); 669 PetscCall(VecScatterBegin(osm->pctoouter, x, y, INSERT_VALUES, SCATTER_REVERSE)); 670 PetscCall(VecScatterEnd(osm->pctoouter, x, y, INSERT_VALUES, SCATTER_REVERSE)); 671 PetscCall(MatDenseRestoreColumnVecWrite(O, i, &y)); 672 PetscCall(MatDenseRestoreColumnVecRead(Xin, i, &x)); 673 } 674 X = Y = O; 675 } else { 676 X = Xin; 677 Y = Yout; 678 } 679 /* 680 support for limiting the restriction or interpolation only to the inner 681 subdomain values (leaving the other values 0). 682 */ 683 PetscCall(VecGetLocalSize(osm->x[0], &m)); 684 PetscCall(VecGetSize(osm->x[0], &M)); 685 PetscCall(MatCreateDense(PetscObjectComm((PetscObject)osm->ois[0]), m, PETSC_DECIDE, M, N, NULL, &Z)); 686 for (i = 0; i < N; ++i) { 687 PetscCall(MatDenseGetColumnVecRead(X, i, &x)); 688 PetscCall(MatDenseGetColumnVecWrite(Z, i, &y)); 689 if (!(osm->type & PC_GASM_RESTRICT)) { 690 /* have to zero the work RHS since scatter may leave some slots empty */ 691 PetscCall(VecZeroEntries(y)); 692 PetscCall(VecScatterBegin(osm->girestriction, x, y, INSERT_VALUES, forward)); 693 PetscCall(VecScatterEnd(osm->girestriction, x, y, INSERT_VALUES, forward)); 694 } else { 695 PetscCall(VecScatterBegin(osm->gorestriction, x, y, INSERT_VALUES, forward)); 696 PetscCall(VecScatterEnd(osm->gorestriction, x, y, INSERT_VALUES, forward)); 697 } 698 PetscCall(MatDenseRestoreColumnVecWrite(Z, i, &y)); 699 PetscCall(MatDenseRestoreColumnVecRead(X, i, &x)); 700 } 701 PetscCall(MatCreateDense(PetscObjectComm((PetscObject)osm->ois[0]), m, PETSC_DECIDE, M, N, NULL, &W)); 702 PetscCall(MatSetOption(Z, MAT_NO_OFF_PROC_ENTRIES, PETSC_TRUE)); 703 PetscCall(MatAssemblyBegin(Z, MAT_FINAL_ASSEMBLY)); 704 PetscCall(MatAssemblyEnd(Z, MAT_FINAL_ASSEMBLY)); 705 /* do the subdomain solve */ 706 PetscCall(KSPMatSolve(osm->ksp[0], Z, W)); 707 PetscCall(KSPCheckSolve(osm->ksp[0], pc, NULL)); 708 PetscCall(MatDestroy(&Z)); 709 /* do we need to zero y? */ 710 PetscCall(MatZeroEntries(Y)); 711 for (i = 0; i < N; ++i) { 712 PetscCall(MatDenseGetColumnVecWrite(Y, i, &y)); 713 PetscCall(MatDenseGetColumnVecRead(W, i, &x)); 714 if (!(osm->type & PC_GASM_INTERPOLATE)) { 715 PetscCall(VecScatterBegin(osm->girestriction, x, y, ADD_VALUES, reverse)); 716 PetscCall(VecScatterEnd(osm->girestriction, x, y, ADD_VALUES, reverse)); 717 } else { 718 PetscCall(VecScatterBegin(osm->gorestriction, x, y, ADD_VALUES, reverse)); 719 PetscCall(VecScatterEnd(osm->gorestriction, x, y, ADD_VALUES, reverse)); 720 } 721 PetscCall(MatDenseRestoreColumnVecRead(W, i, &x)); 722 if (osm->pctoouter) { 723 PetscCall(MatDenseGetColumnVecWrite(Yout, i, &x)); 724 PetscCall(VecScatterBegin(osm->pctoouter, y, x, INSERT_VALUES, SCATTER_FORWARD)); 725 PetscCall(VecScatterEnd(osm->pctoouter, y, x, INSERT_VALUES, SCATTER_FORWARD)); 726 PetscCall(MatDenseRestoreColumnVecRead(Yout, i, &x)); 727 } 728 PetscCall(MatDenseRestoreColumnVecWrite(Y, i, &y)); 729 } 730 PetscCall(MatDestroy(&W)); 731 PetscCall(MatDestroy(&O)); 732 PetscFunctionReturn(PETSC_SUCCESS); 733 } 734 735 static PetscErrorCode PCApplyTranspose_GASM(PC pc, Vec xin, Vec yout) 736 { 737 PC_GASM *osm = (PC_GASM *)pc->data; 738 PetscInt i; 739 Vec x, y; 740 ScatterMode forward = SCATTER_FORWARD, reverse = SCATTER_REVERSE; 741 742 PetscFunctionBegin; 743 if (osm->pctoouter) { 744 PetscCall(VecScatterBegin(osm->pctoouter, xin, osm->pcx, INSERT_VALUES, SCATTER_REVERSE)); 745 PetscCall(VecScatterEnd(osm->pctoouter, xin, osm->pcx, INSERT_VALUES, SCATTER_REVERSE)); 746 x = osm->pcx; 747 y = osm->pcy; 748 } else { 749 x = xin; 750 y = yout; 751 } 752 /* 753 Support for limiting the restriction or interpolation to only local 754 subdomain values (leaving the other values 0). 755 756 Note: these are reversed from the PCApply_GASM() because we are applying the 757 transpose of the three terms 758 */ 759 if (!(osm->type & PC_GASM_INTERPOLATE)) { 760 /* have to zero the work RHS since scatter may leave some slots empty */ 761 PetscCall(VecZeroEntries(osm->gx)); 762 PetscCall(VecScatterBegin(osm->girestriction, x, osm->gx, INSERT_VALUES, forward)); 763 } else { 764 PetscCall(VecScatterBegin(osm->gorestriction, x, osm->gx, INSERT_VALUES, forward)); 765 } 766 PetscCall(VecZeroEntries(osm->gy)); 767 if (!(osm->type & PC_GASM_INTERPOLATE)) { 768 PetscCall(VecScatterEnd(osm->girestriction, x, osm->gx, INSERT_VALUES, forward)); 769 } else { 770 PetscCall(VecScatterEnd(osm->gorestriction, x, osm->gx, INSERT_VALUES, forward)); 771 } 772 /* do the local solves */ 773 for (i = 0; i < osm->n; ++i) { /* Note that the solves are local, so we can go to osm->n, rather than osm->nmax. */ 774 PetscCall(KSPSolveTranspose(osm->ksp[i], osm->x[i], osm->y[i])); 775 PetscCall(KSPCheckSolve(osm->ksp[i], pc, osm->y[i])); 776 } 777 PetscCall(VecZeroEntries(y)); 778 if (!(osm->type & PC_GASM_RESTRICT)) { 779 PetscCall(VecScatterBegin(osm->girestriction, osm->gy, y, ADD_VALUES, reverse)); 780 PetscCall(VecScatterEnd(osm->girestriction, osm->gy, y, ADD_VALUES, reverse)); 781 } else { 782 PetscCall(VecScatterBegin(osm->gorestriction, osm->gy, y, ADD_VALUES, reverse)); 783 PetscCall(VecScatterEnd(osm->gorestriction, osm->gy, y, ADD_VALUES, reverse)); 784 } 785 if (osm->pctoouter) { 786 PetscCall(VecScatterBegin(osm->pctoouter, y, yout, INSERT_VALUES, SCATTER_FORWARD)); 787 PetscCall(VecScatterEnd(osm->pctoouter, y, yout, INSERT_VALUES, SCATTER_FORWARD)); 788 } 789 PetscFunctionReturn(PETSC_SUCCESS); 790 } 791 792 static PetscErrorCode PCReset_GASM(PC pc) 793 { 794 PC_GASM *osm = (PC_GASM *)pc->data; 795 PetscInt i; 796 797 PetscFunctionBegin; 798 if (osm->ksp) { 799 for (i = 0; i < osm->n; i++) PetscCall(KSPReset(osm->ksp[i])); 800 } 801 if (osm->pmat) { 802 if (osm->n > 0) { 803 PetscMPIInt size; 804 PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)pc), &size)); 805 if (size > 1) { 806 /* osm->pmat is created by MatCreateSubMatricesMPI(), cannot use MatDestroySubMatrices() */ 807 PetscCall(MatDestroyMatrices(osm->n, &osm->pmat)); 808 } else { 809 PetscCall(MatDestroySubMatrices(osm->n, &osm->pmat)); 810 } 811 } 812 } 813 if (osm->x) { 814 for (i = 0; i < osm->n; i++) { 815 PetscCall(VecDestroy(&osm->x[i])); 816 PetscCall(VecDestroy(&osm->y[i])); 817 } 818 } 819 PetscCall(VecDestroy(&osm->gx)); 820 PetscCall(VecDestroy(&osm->gy)); 821 822 PetscCall(VecScatterDestroy(&osm->gorestriction)); 823 PetscCall(VecScatterDestroy(&osm->girestriction)); 824 if (!osm->user_subdomains) { 825 PetscCall(PCGASMDestroySubdomains(osm->n, &osm->ois, &osm->iis)); 826 osm->N = PETSC_DETERMINE; 827 osm->nmax = PETSC_DETERMINE; 828 } 829 if (osm->pctoouter) PetscCall(VecScatterDestroy(&(osm->pctoouter))); 830 if (osm->permutationIS) PetscCall(ISDestroy(&(osm->permutationIS))); 831 if (osm->pcx) PetscCall(VecDestroy(&(osm->pcx))); 832 if (osm->pcy) PetscCall(VecDestroy(&(osm->pcy))); 833 if (osm->permutationP) PetscCall(MatDestroy(&(osm->permutationP))); 834 if (osm->pcmat) PetscCall(MatDestroy(&osm->pcmat)); 835 PetscFunctionReturn(PETSC_SUCCESS); 836 } 837 838 static PetscErrorCode PCDestroy_GASM(PC pc) 839 { 840 PC_GASM *osm = (PC_GASM *)pc->data; 841 PetscInt i; 842 843 PetscFunctionBegin; 844 PetscCall(PCReset_GASM(pc)); 845 /* PCReset will not destroy subdomains, if user_subdomains is true. */ 846 PetscCall(PCGASMDestroySubdomains(osm->n, &osm->ois, &osm->iis)); 847 if (osm->ksp) { 848 for (i = 0; i < osm->n; i++) PetscCall(KSPDestroy(&osm->ksp[i])); 849 PetscCall(PetscFree(osm->ksp)); 850 } 851 PetscCall(PetscFree(osm->x)); 852 PetscCall(PetscFree(osm->y)); 853 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCGASMSetSubdomains_C", NULL)); 854 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCGASMSetOverlap_C", NULL)); 855 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCGASMSetType_C", NULL)); 856 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCGASMSetSortIndices_C", NULL)); 857 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCGASMGetSubKSP_C", NULL)); 858 PetscCall(PetscFree(pc->data)); 859 PetscFunctionReturn(PETSC_SUCCESS); 860 } 861 862 static PetscErrorCode PCSetFromOptions_GASM(PC pc, PetscOptionItems *PetscOptionsObject) 863 { 864 PC_GASM *osm = (PC_GASM *)pc->data; 865 PetscInt blocks, ovl; 866 PetscBool flg; 867 PCGASMType gasmtype; 868 869 PetscFunctionBegin; 870 PetscOptionsHeadBegin(PetscOptionsObject, "Generalized additive Schwarz options"); 871 PetscCall(PetscOptionsBool("-pc_gasm_use_dm_subdomains", "If subdomains aren't set, use DMCreateDomainDecomposition() to define subdomains.", "PCGASMSetUseDMSubdomains", osm->dm_subdomains, &osm->dm_subdomains, &flg)); 872 PetscCall(PetscOptionsInt("-pc_gasm_total_subdomains", "Total number of subdomains across communicator", "PCGASMSetTotalSubdomains", osm->N, &blocks, &flg)); 873 if (flg) PetscCall(PCGASMSetTotalSubdomains(pc, blocks)); 874 PetscCall(PetscOptionsInt("-pc_gasm_overlap", "Number of overlapping degrees of freedom", "PCGASMSetOverlap", osm->overlap, &ovl, &flg)); 875 if (flg) { 876 PetscCall(PCGASMSetOverlap(pc, ovl)); 877 osm->dm_subdomains = PETSC_FALSE; 878 } 879 flg = PETSC_FALSE; 880 PetscCall(PetscOptionsEnum("-pc_gasm_type", "Type of restriction/extension", "PCGASMSetType", PCGASMTypes, (PetscEnum)osm->type, (PetscEnum *)&gasmtype, &flg)); 881 if (flg) PetscCall(PCGASMSetType(pc, gasmtype)); 882 PetscCall(PetscOptionsBool("-pc_gasm_use_hierachical_partitioning", "use hierarchical partitioning", NULL, osm->hierarchicalpartitioning, &osm->hierarchicalpartitioning, &flg)); 883 PetscOptionsHeadEnd(); 884 PetscFunctionReturn(PETSC_SUCCESS); 885 } 886 887 /*@ 888 PCGASMSetTotalSubdomains - sets the total number of subdomains to use across the communicator for `PCGASM` 889 890 Logically Collective 891 892 Input Parameters: 893 + pc - the preconditioner 894 - N - total number of subdomains 895 896 Level: beginner 897 898 .seealso: `PCGASM`, `PCGASMSetSubdomains()`, `PCGASMSetOverlap()` 899 `PCGASMCreateSubdomains2D()` 900 @*/ 901 PetscErrorCode PCGASMSetTotalSubdomains(PC pc, PetscInt N) 902 { 903 PC_GASM *osm = (PC_GASM *)pc->data; 904 PetscMPIInt size, rank; 905 906 PetscFunctionBegin; 907 PetscCheck(N >= 1, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Total number of subdomains must be 1 or more, got N = %" PetscInt_FMT, N); 908 PetscCheck(!pc->setupcalled, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONGSTATE, "PCGASMSetTotalSubdomains() should be called before calling PCSetUp()."); 909 910 PetscCall(PCGASMDestroySubdomains(osm->n, &osm->iis, &osm->ois)); 911 osm->ois = osm->iis = NULL; 912 913 PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)pc), &size)); 914 PetscCallMPI(MPI_Comm_rank(PetscObjectComm((PetscObject)pc), &rank)); 915 osm->N = N; 916 osm->n = PETSC_DETERMINE; 917 osm->nmax = PETSC_DETERMINE; 918 osm->dm_subdomains = PETSC_FALSE; 919 PetscFunctionReturn(PETSC_SUCCESS); 920 } 921 922 static PetscErrorCode PCGASMSetSubdomains_GASM(PC pc, PetscInt n, IS iis[], IS ois[]) 923 { 924 PC_GASM *osm = (PC_GASM *)pc->data; 925 PetscInt i; 926 927 PetscFunctionBegin; 928 PetscCheck(n >= 1, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Each MPI rank must have 1 or more subdomains, got n = %" PetscInt_FMT, n); 929 PetscCheck(!pc->setupcalled, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONGSTATE, "PCGASMSetSubdomains() should be called before calling PCSetUp()."); 930 931 PetscCall(PCGASMDestroySubdomains(osm->n, &osm->iis, &osm->ois)); 932 osm->iis = osm->ois = NULL; 933 osm->n = n; 934 osm->N = PETSC_DETERMINE; 935 osm->nmax = PETSC_DETERMINE; 936 if (ois) { 937 PetscCall(PetscMalloc1(n, &osm->ois)); 938 for (i = 0; i < n; i++) { 939 PetscCall(PetscObjectReference((PetscObject)ois[i])); 940 osm->ois[i] = ois[i]; 941 } 942 /* 943 Since the user set the outer subdomains, even if nontrivial overlap was requested via PCGASMSetOverlap(), 944 it will be ignored. To avoid confusion later on (e.g., when viewing the PC), the overlap size is set to -1. 945 */ 946 osm->overlap = -1; 947 /* inner subdomains must be provided */ 948 PetscCheck(iis, PETSC_COMM_SELF, PETSC_ERR_ARG_NULL, "inner indices have to be provided "); 949 } /* end if */ 950 if (iis) { 951 PetscCall(PetscMalloc1(n, &osm->iis)); 952 for (i = 0; i < n; i++) { 953 PetscCall(PetscObjectReference((PetscObject)iis[i])); 954 osm->iis[i] = iis[i]; 955 } 956 if (!ois) { 957 osm->ois = NULL; 958 /* if user does not provide outer indices, we will create the corresponding outer indices using osm->overlap =1 in PCSetUp_GASM */ 959 } 960 } 961 if (PetscDefined(USE_DEBUG)) { 962 PetscInt j, rstart, rend, *covered, lsize; 963 const PetscInt *indices; 964 /* check if the inner indices cover and only cover the local portion of the preconditioning matrix */ 965 PetscCall(MatGetOwnershipRange(pc->pmat, &rstart, &rend)); 966 PetscCall(PetscCalloc1(rend - rstart, &covered)); 967 /* check if the current MPI rank owns indices from others */ 968 for (i = 0; i < n; i++) { 969 PetscCall(ISGetIndices(osm->iis[i], &indices)); 970 PetscCall(ISGetLocalSize(osm->iis[i], &lsize)); 971 for (j = 0; j < lsize; j++) { 972 PetscCheck(indices[j] >= rstart && indices[j] < rend, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "inner subdomains can not own an index %" PetscInt_FMT " from other ranks", indices[j]); 973 PetscCheck(covered[indices[j] - rstart] != 1, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "inner subdomains can not have an overlapping index %" PetscInt_FMT " ", indices[j]); 974 covered[indices[j] - rstart] = 1; 975 } 976 PetscCall(ISRestoreIndices(osm->iis[i], &indices)); 977 } 978 /* check if we miss any indices */ 979 for (i = rstart; i < rend; i++) PetscCheck(covered[i - rstart], PETSC_COMM_SELF, PETSC_ERR_ARG_NULL, "local entity %" PetscInt_FMT " was not covered by inner subdomains", i); 980 PetscCall(PetscFree(covered)); 981 } 982 if (iis) osm->user_subdomains = PETSC_TRUE; 983 PetscFunctionReturn(PETSC_SUCCESS); 984 } 985 986 static PetscErrorCode PCGASMSetOverlap_GASM(PC pc, PetscInt ovl) 987 { 988 PC_GASM *osm = (PC_GASM *)pc->data; 989 990 PetscFunctionBegin; 991 PetscCheck(ovl >= 0, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_OUTOFRANGE, "Negative overlap value requested"); 992 PetscCheck(!pc->setupcalled || ovl == osm->overlap, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONGSTATE, "PCGASMSetOverlap() should be called before PCSetUp()."); 993 if (!pc->setupcalled) osm->overlap = ovl; 994 PetscFunctionReturn(PETSC_SUCCESS); 995 } 996 997 static PetscErrorCode PCGASMSetType_GASM(PC pc, PCGASMType type) 998 { 999 PC_GASM *osm = (PC_GASM *)pc->data; 1000 1001 PetscFunctionBegin; 1002 osm->type = type; 1003 osm->type_set = PETSC_TRUE; 1004 PetscFunctionReturn(PETSC_SUCCESS); 1005 } 1006 1007 static PetscErrorCode PCGASMSetSortIndices_GASM(PC pc, PetscBool doSort) 1008 { 1009 PC_GASM *osm = (PC_GASM *)pc->data; 1010 1011 PetscFunctionBegin; 1012 osm->sort_indices = doSort; 1013 PetscFunctionReturn(PETSC_SUCCESS); 1014 } 1015 1016 /* 1017 FIXME: This routine might need to be modified now that multiple ranks per subdomain are allowed. 1018 In particular, it would upset the global subdomain number calculation. 1019 */ 1020 static PetscErrorCode PCGASMGetSubKSP_GASM(PC pc, PetscInt *n, PetscInt *first, KSP **ksp) 1021 { 1022 PC_GASM *osm = (PC_GASM *)pc->data; 1023 1024 PetscFunctionBegin; 1025 PetscCheck(osm->n >= 1, PetscObjectComm((PetscObject)pc), PETSC_ERR_ORDER, "Need to call PCSetUp() on PC (or KSPSetUp() on the outer KSP object) before calling here"); 1026 1027 if (n) *n = osm->n; 1028 if (first) { 1029 PetscCallMPI(MPI_Scan(&osm->n, first, 1, MPIU_INT, MPI_SUM, PetscObjectComm((PetscObject)pc))); 1030 *first -= osm->n; 1031 } 1032 if (ksp) { 1033 /* Assume that local solves are now different; not necessarily 1034 true, though! This flag is used only for PCView_GASM() */ 1035 *ksp = osm->ksp; 1036 osm->same_subdomain_solvers = PETSC_FALSE; 1037 } 1038 PetscFunctionReturn(PETSC_SUCCESS); 1039 } /* PCGASMGetSubKSP_GASM() */ 1040 1041 /*@C 1042 PCGASMSetSubdomains - Sets the subdomains for this MPI rank 1043 for the additive Schwarz preconditioner with multiple MPI ranks per subdomain, `PCGASM` 1044 1045 Collective 1046 1047 Input Parameters: 1048 + pc - the preconditioner object 1049 . n - the number of subdomains for this MPI rank 1050 . iis - the index sets that define the inner subdomains (or `NULL` for PETSc to determine subdomains) 1051 - ois - the index sets that define the outer subdomains (or `NULL` to use the same as `iis`, or to construct by expanding `iis` by 1052 the requested overlap) 1053 1054 Level: advanced 1055 1056 Notes: 1057 The `IS` indices use the parallel, global numbering of the vector entries. 1058 1059 Inner subdomains are those where the correction is applied. 1060 1061 Outer subdomains are those where the residual necessary to obtain the 1062 corrections is obtained (see `PCGASMType` for the use of inner/outer subdomains). 1063 1064 Both inner and outer subdomains can extend over several MPI ranks. 1065 This rank's portion of a subdomain is known as a local subdomain. 1066 1067 Inner subdomains can not overlap with each other, do not have any entities from remote ranks, 1068 and have to cover the entire local subdomain owned by the current rank. The index sets on each 1069 rank should be ordered such that the ith local subdomain is connected to the ith remote subdomain 1070 on another MPI rank. 1071 1072 By default the `PGASM` preconditioner uses 1 (local) subdomain per MPI rank. 1073 1074 The `iis` and `ois` arrays may be freed after this call using `PCGASMDestroySubdomains()` 1075 1076 .seealso: `PCGASM`, `PCGASMSetOverlap()`, `PCGASMGetSubKSP()`, `PCGASMDestroySubdomains()`, 1077 `PCGASMCreateSubdomains2D()`, `PCGASMGetSubdomains()` 1078 @*/ 1079 PetscErrorCode PCGASMSetSubdomains(PC pc, PetscInt n, IS iis[], IS ois[]) 1080 { 1081 PC_GASM *osm = (PC_GASM *)pc->data; 1082 1083 PetscFunctionBegin; 1084 PetscValidHeaderSpecific(pc, PC_CLASSID, 1); 1085 PetscTryMethod(pc, "PCGASMSetSubdomains_C", (PC, PetscInt, IS[], IS[]), (pc, n, iis, ois)); 1086 osm->dm_subdomains = PETSC_FALSE; 1087 PetscFunctionReturn(PETSC_SUCCESS); 1088 } 1089 1090 /*@ 1091 PCGASMSetOverlap - Sets the overlap between a pair of subdomains for the 1092 additive Schwarz preconditioner `PCGASM`. Either all or no MPI ranks in the 1093 pc communicator must call this routine. 1094 1095 Logically Collective 1096 1097 Input Parameters: 1098 + pc - the preconditioner context 1099 - ovl - the amount of overlap between subdomains (ovl >= 0, default value = 0) 1100 1101 Options Database Key: 1102 . -pc_gasm_overlap <overlap> - Sets overlap 1103 1104 Level: intermediate 1105 1106 Notes: 1107 By default the `PCGASM` preconditioner uses 1 subdomain per rank. To use 1108 multiple subdomain per perocessor or "straddling" subdomains that intersect 1109 multiple ranks use `PCGASMSetSubdomains()` (or option `-pc_gasm_total_subdomains` <n>). 1110 1111 The overlap defaults to 0, so if one desires that no additional 1112 overlap be computed beyond what may have been set with a call to 1113 `PCGASMSetSubdomains()`, then `ovl` must be set to be 0. In particular, if one does 1114 not explicitly set the subdomains in application code, then all overlap would be computed 1115 internally by PETSc, and using an overlap of 0 would result in an `PCGASM` 1116 variant that is equivalent to the block Jacobi preconditioner. 1117 1118 One can define initial index sets with any overlap via 1119 `PCGASMSetSubdomains()`; the routine `PCGASMSetOverlap()` merely allows 1120 PETSc to extend that overlap further, if desired. 1121 1122 .seealso: `PCGASM`, `PCGASMSetSubdomains()`, `PCGASMGetSubKSP()`, 1123 `PCGASMCreateSubdomains2D()`, `PCGASMGetSubdomains()` 1124 @*/ 1125 PetscErrorCode PCGASMSetOverlap(PC pc, PetscInt ovl) 1126 { 1127 PC_GASM *osm = (PC_GASM *)pc->data; 1128 1129 PetscFunctionBegin; 1130 PetscValidHeaderSpecific(pc, PC_CLASSID, 1); 1131 PetscValidLogicalCollectiveInt(pc, ovl, 2); 1132 PetscTryMethod(pc, "PCGASMSetOverlap_C", (PC, PetscInt), (pc, ovl)); 1133 osm->dm_subdomains = PETSC_FALSE; 1134 PetscFunctionReturn(PETSC_SUCCESS); 1135 } 1136 1137 /*@ 1138 PCGASMSetType - Sets the type of restriction and interpolation used 1139 for local problems in the `PCGASM` additive Schwarz method. 1140 1141 Logically Collective 1142 1143 Input Parameters: 1144 + pc - the preconditioner context 1145 - type - variant of `PCGASM`, one of 1146 .vb 1147 `PC_GASM_BASIC` - full interpolation and restriction 1148 `PC_GASM_RESTRICT` - full restriction, local MPI rank interpolation 1149 `PC_GASM_INTERPOLATE` - full interpolation, local MPI rank restriction 1150 `PC_GASM_NONE` - local MPI rank restriction and interpolation 1151 .ve 1152 1153 Options Database Key: 1154 . -pc_gasm_type [basic,restrict,interpolate,none] - Sets `PCGASM` type 1155 1156 Level: intermediate 1157 1158 .seealso: `PCGASM`, `PCGASMSetSubdomains()`, `PCGASMGetSubKSP()`, 1159 `PCGASMCreateSubdomains2D()`, `PCASM`, `PCASMSetType()` 1160 @*/ 1161 PetscErrorCode PCGASMSetType(PC pc, PCGASMType type) 1162 { 1163 PetscFunctionBegin; 1164 PetscValidHeaderSpecific(pc, PC_CLASSID, 1); 1165 PetscValidLogicalCollectiveEnum(pc, type, 2); 1166 PetscTryMethod(pc, "PCGASMSetType_C", (PC, PCGASMType), (pc, type)); 1167 PetscFunctionReturn(PETSC_SUCCESS); 1168 } 1169 1170 /*@ 1171 PCGASMSetSortIndices - Determines whether subdomain indices are sorted. 1172 1173 Logically Collective 1174 1175 Input Parameters: 1176 + pc - the preconditioner context 1177 - doSort - sort the subdomain indices 1178 1179 Level: intermediate 1180 1181 .seealso: `PCGASM`, `PCGASMSetSubdomains()`, `PCGASMGetSubKSP()`, 1182 `PCGASMCreateSubdomains2D()` 1183 @*/ 1184 PetscErrorCode PCGASMSetSortIndices(PC pc, PetscBool doSort) 1185 { 1186 PetscFunctionBegin; 1187 PetscValidHeaderSpecific(pc, PC_CLASSID, 1); 1188 PetscValidLogicalCollectiveBool(pc, doSort, 2); 1189 PetscTryMethod(pc, "PCGASMSetSortIndices_C", (PC, PetscBool), (pc, doSort)); 1190 PetscFunctionReturn(PETSC_SUCCESS); 1191 } 1192 1193 /*@C 1194 PCGASMGetSubKSP - Gets the local `KSP` contexts for all subdomains on 1195 this MPI rank. 1196 1197 Collective iff first_local is requested 1198 1199 Input Parameter: 1200 . pc - the preconditioner context 1201 1202 Output Parameters: 1203 + n_local - the number of blocks on this MPI rank or `NULL` 1204 . first_local - the global number of the first block on this rank or `NULL`, 1205 all ranks must request or all must pass `NULL` 1206 - ksp - the array of `KSP` contexts 1207 1208 Level: advanced 1209 1210 Note: 1211 After `PCGASMGetSubKSP()` the array of `KSP`es is not to be freed 1212 1213 Currently for some matrix implementations only 1 block per MPI process 1214 is supported. 1215 1216 You must call `KSPSetUp()` before calling `PCGASMGetSubKSP()`. 1217 1218 .seealso: `PCGASM`, `PCGASMSetSubdomains()`, `PCGASMSetOverlap()`, 1219 `PCGASMCreateSubdomains2D()`, 1220 @*/ 1221 PetscErrorCode PCGASMGetSubKSP(PC pc, PetscInt *n_local, PetscInt *first_local, KSP *ksp[]) 1222 { 1223 PetscFunctionBegin; 1224 PetscValidHeaderSpecific(pc, PC_CLASSID, 1); 1225 PetscUseMethod(pc, "PCGASMGetSubKSP_C", (PC, PetscInt *, PetscInt *, KSP **), (pc, n_local, first_local, ksp)); 1226 PetscFunctionReturn(PETSC_SUCCESS); 1227 } 1228 1229 /*MC 1230 PCGASM - Use the (restricted) additive Schwarz method, each block is (approximately) solved with 1231 its own `KSP` object on a subset of MPI ranks 1232 1233 Options Database Keys: 1234 + -pc_gasm_total_subdomains <n> - Sets total number of local subdomains to be distributed among MPI ranks 1235 . -pc_gasm_view_subdomains - activates the printing of subdomain indices in `PCView()`, -ksp_view or -snes_view 1236 . -pc_gasm_print_subdomains - activates the printing of subdomain indices in `PCSetUp()` 1237 . -pc_gasm_overlap <ovl> - Sets overlap by which to (automatically) extend local subdomains 1238 - -pc_gasm_type [basic,restrict,interpolate,none] - Sets `PCGASMType` 1239 1240 Level: beginner 1241 1242 Notes: 1243 To set options on the solvers for each block append `-sub_` to all the `KSP`, and `PC` 1244 options database keys. For example, `-sub_pc_type ilu -sub_pc_factor_levels 1 -sub_ksp_type preonly` 1245 1246 To set the options on the solvers separate for each block call `PCGASMGetSubKSP()` 1247 and set the options directly on the resulting `KSP` object (you can access its `PC` 1248 with `KSPGetPC()`) 1249 1250 References: 1251 + * - M Dryja, OB Widlund, An additive variant of the Schwarz alternating method for the case of many subregions 1252 Courant Institute, New York University Technical report 1253 - * - Barry Smith, Petter Bjorstad, and William Gropp, Domain Decompositions: Parallel Multilevel Methods for Elliptic Partial Differential Equations, 1254 Cambridge University Press. 1255 1256 .seealso: `PCCreate()`, `PCSetType()`, `PCType`, `PC`, `PCASM`, `PCGASMType`, `PCGASMSetType()`, 1257 `PCBJACOBI`, `PCGASMGetSubKSP()`, `PCGASMSetSubdomains()`, 1258 `PCSetModifySubMatrices()`, `PCGASMSetOverlap()`, `PCGASMSetType()` 1259 M*/ 1260 1261 PETSC_EXTERN PetscErrorCode PCCreate_GASM(PC pc) 1262 { 1263 PC_GASM *osm; 1264 1265 PetscFunctionBegin; 1266 PetscCall(PetscNew(&osm)); 1267 1268 osm->N = PETSC_DETERMINE; 1269 osm->n = PETSC_DECIDE; 1270 osm->nmax = PETSC_DETERMINE; 1271 osm->overlap = 0; 1272 osm->ksp = NULL; 1273 osm->gorestriction = NULL; 1274 osm->girestriction = NULL; 1275 osm->pctoouter = NULL; 1276 osm->gx = NULL; 1277 osm->gy = NULL; 1278 osm->x = NULL; 1279 osm->y = NULL; 1280 osm->pcx = NULL; 1281 osm->pcy = NULL; 1282 osm->permutationIS = NULL; 1283 osm->permutationP = NULL; 1284 osm->pcmat = NULL; 1285 osm->ois = NULL; 1286 osm->iis = NULL; 1287 osm->pmat = NULL; 1288 osm->type = PC_GASM_RESTRICT; 1289 osm->same_subdomain_solvers = PETSC_TRUE; 1290 osm->sort_indices = PETSC_TRUE; 1291 osm->dm_subdomains = PETSC_FALSE; 1292 osm->hierarchicalpartitioning = PETSC_FALSE; 1293 1294 pc->data = (void *)osm; 1295 pc->ops->apply = PCApply_GASM; 1296 pc->ops->matapply = PCMatApply_GASM; 1297 pc->ops->applytranspose = PCApplyTranspose_GASM; 1298 pc->ops->setup = PCSetUp_GASM; 1299 pc->ops->reset = PCReset_GASM; 1300 pc->ops->destroy = PCDestroy_GASM; 1301 pc->ops->setfromoptions = PCSetFromOptions_GASM; 1302 pc->ops->setuponblocks = PCSetUpOnBlocks_GASM; 1303 pc->ops->view = PCView_GASM; 1304 pc->ops->applyrichardson = NULL; 1305 1306 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCGASMSetSubdomains_C", PCGASMSetSubdomains_GASM)); 1307 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCGASMSetOverlap_C", PCGASMSetOverlap_GASM)); 1308 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCGASMSetType_C", PCGASMSetType_GASM)); 1309 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCGASMSetSortIndices_C", PCGASMSetSortIndices_GASM)); 1310 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCGASMGetSubKSP_C", PCGASMGetSubKSP_GASM)); 1311 PetscFunctionReturn(PETSC_SUCCESS); 1312 } 1313 1314 PetscErrorCode PCGASMCreateLocalSubdomains(Mat A, PetscInt nloc, IS *iis[]) 1315 { 1316 MatPartitioning mpart; 1317 const char *prefix; 1318 PetscInt i, j, rstart, rend, bs; 1319 PetscBool hasop, isbaij = PETSC_FALSE, foundpart = PETSC_FALSE; 1320 Mat Ad = NULL, adj; 1321 IS ispart, isnumb, *is; 1322 1323 PetscFunctionBegin; 1324 PetscCheck(nloc >= 1, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "number of local subdomains must > 0, got nloc = %" PetscInt_FMT, nloc); 1325 1326 /* Get prefix, row distribution, and block size */ 1327 PetscCall(MatGetOptionsPrefix(A, &prefix)); 1328 PetscCall(MatGetOwnershipRange(A, &rstart, &rend)); 1329 PetscCall(MatGetBlockSize(A, &bs)); 1330 PetscCheck(rstart / bs * bs == rstart && rend / bs * bs == rend, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "bad row distribution [%" PetscInt_FMT ",%" PetscInt_FMT ") for matrix block size %" PetscInt_FMT, rstart, rend, bs); 1331 1332 /* Get diagonal block from matrix if possible */ 1333 PetscCall(MatHasOperation(A, MATOP_GET_DIAGONAL_BLOCK, &hasop)); 1334 if (hasop) PetscCall(MatGetDiagonalBlock(A, &Ad)); 1335 if (Ad) { 1336 PetscCall(PetscObjectBaseTypeCompare((PetscObject)Ad, MATSEQBAIJ, &isbaij)); 1337 if (!isbaij) PetscCall(PetscObjectBaseTypeCompare((PetscObject)Ad, MATSEQSBAIJ, &isbaij)); 1338 } 1339 if (Ad && nloc > 1) { 1340 PetscBool match, done; 1341 /* Try to setup a good matrix partitioning if available */ 1342 PetscCall(MatPartitioningCreate(PETSC_COMM_SELF, &mpart)); 1343 PetscCall(PetscObjectSetOptionsPrefix((PetscObject)mpart, prefix)); 1344 PetscCall(MatPartitioningSetFromOptions(mpart)); 1345 PetscCall(PetscObjectTypeCompare((PetscObject)mpart, MATPARTITIONINGCURRENT, &match)); 1346 if (!match) PetscCall(PetscObjectTypeCompare((PetscObject)mpart, MATPARTITIONINGSQUARE, &match)); 1347 if (!match) { /* assume a "good" partitioner is available */ 1348 PetscInt na; 1349 const PetscInt *ia, *ja; 1350 PetscCall(MatGetRowIJ(Ad, 0, PETSC_TRUE, isbaij, &na, &ia, &ja, &done)); 1351 if (done) { 1352 /* Build adjacency matrix by hand. Unfortunately a call to 1353 MatConvert(Ad,MATMPIADJ,MAT_INITIAL_MATRIX,&adj) will 1354 remove the block-aij structure and we cannot expect 1355 MatPartitioning to split vertices as we need */ 1356 PetscInt i, j, len, nnz, cnt, *iia = NULL, *jja = NULL; 1357 const PetscInt *row; 1358 nnz = 0; 1359 for (i = 0; i < na; i++) { /* count number of nonzeros */ 1360 len = ia[i + 1] - ia[i]; 1361 row = ja + ia[i]; 1362 for (j = 0; j < len; j++) { 1363 if (row[j] == i) { /* don't count diagonal */ 1364 len--; 1365 break; 1366 } 1367 } 1368 nnz += len; 1369 } 1370 PetscCall(PetscMalloc1(na + 1, &iia)); 1371 PetscCall(PetscMalloc1(nnz, &jja)); 1372 nnz = 0; 1373 iia[0] = 0; 1374 for (i = 0; i < na; i++) { /* fill adjacency */ 1375 cnt = 0; 1376 len = ia[i + 1] - ia[i]; 1377 row = ja + ia[i]; 1378 for (j = 0; j < len; j++) { 1379 if (row[j] != i) jja[nnz + cnt++] = row[j]; /* if not diagonal */ 1380 } 1381 nnz += cnt; 1382 iia[i + 1] = nnz; 1383 } 1384 /* Partitioning of the adjacency matrix */ 1385 PetscCall(MatCreateMPIAdj(PETSC_COMM_SELF, na, na, iia, jja, NULL, &adj)); 1386 PetscCall(MatPartitioningSetAdjacency(mpart, adj)); 1387 PetscCall(MatPartitioningSetNParts(mpart, nloc)); 1388 PetscCall(MatPartitioningApply(mpart, &ispart)); 1389 PetscCall(ISPartitioningToNumbering(ispart, &isnumb)); 1390 PetscCall(MatDestroy(&adj)); 1391 foundpart = PETSC_TRUE; 1392 } 1393 PetscCall(MatRestoreRowIJ(Ad, 0, PETSC_TRUE, isbaij, &na, &ia, &ja, &done)); 1394 } 1395 PetscCall(MatPartitioningDestroy(&mpart)); 1396 } 1397 PetscCall(PetscMalloc1(nloc, &is)); 1398 if (!foundpart) { 1399 /* Partitioning by contiguous chunks of rows */ 1400 1401 PetscInt mbs = (rend - rstart) / bs; 1402 PetscInt start = rstart; 1403 for (i = 0; i < nloc; i++) { 1404 PetscInt count = (mbs / nloc + ((mbs % nloc) > i)) * bs; 1405 PetscCall(ISCreateStride(PETSC_COMM_SELF, count, start, 1, &is[i])); 1406 start += count; 1407 } 1408 1409 } else { 1410 /* Partitioning by adjacency of diagonal block */ 1411 1412 const PetscInt *numbering; 1413 PetscInt *count, nidx, *indices, *newidx, start = 0; 1414 /* Get node count in each partition */ 1415 PetscCall(PetscMalloc1(nloc, &count)); 1416 PetscCall(ISPartitioningCount(ispart, nloc, count)); 1417 if (isbaij && bs > 1) { /* adjust for the block-aij case */ 1418 for (i = 0; i < nloc; i++) count[i] *= bs; 1419 } 1420 /* Build indices from node numbering */ 1421 PetscCall(ISGetLocalSize(isnumb, &nidx)); 1422 PetscCall(PetscMalloc1(nidx, &indices)); 1423 for (i = 0; i < nidx; i++) indices[i] = i; /* needs to be initialized */ 1424 PetscCall(ISGetIndices(isnumb, &numbering)); 1425 PetscCall(PetscSortIntWithPermutation(nidx, numbering, indices)); 1426 PetscCall(ISRestoreIndices(isnumb, &numbering)); 1427 if (isbaij && bs > 1) { /* adjust for the block-aij case */ 1428 PetscCall(PetscMalloc1(nidx * bs, &newidx)); 1429 for (i = 0; i < nidx; i++) { 1430 for (j = 0; j < bs; j++) newidx[i * bs + j] = indices[i] * bs + j; 1431 } 1432 PetscCall(PetscFree(indices)); 1433 nidx *= bs; 1434 indices = newidx; 1435 } 1436 /* Shift to get global indices */ 1437 for (i = 0; i < nidx; i++) indices[i] += rstart; 1438 1439 /* Build the index sets for each block */ 1440 for (i = 0; i < nloc; i++) { 1441 PetscCall(ISCreateGeneral(PETSC_COMM_SELF, count[i], &indices[start], PETSC_COPY_VALUES, &is[i])); 1442 PetscCall(ISSort(is[i])); 1443 start += count[i]; 1444 } 1445 1446 PetscCall(PetscFree(count)); 1447 PetscCall(PetscFree(indices)); 1448 PetscCall(ISDestroy(&isnumb)); 1449 PetscCall(ISDestroy(&ispart)); 1450 } 1451 *iis = is; 1452 PetscFunctionReturn(PETSC_SUCCESS); 1453 } 1454 1455 PETSC_INTERN PetscErrorCode PCGASMCreateStraddlingSubdomains(Mat A, PetscInt N, PetscInt *n, IS *iis[]) 1456 { 1457 PetscFunctionBegin; 1458 PetscCall(MatSubdomainsCreateCoalesce(A, N, n, iis)); 1459 PetscFunctionReturn(PETSC_SUCCESS); 1460 } 1461 1462 /*@C 1463 PCGASMCreateSubdomains - Creates `n` index sets defining `n` nonoverlapping subdomains on this MPI process for the `PCGASM` additive 1464 Schwarz preconditioner for a any problem based on its matrix. 1465 1466 Collective 1467 1468 Input Parameters: 1469 + A - The global matrix operator 1470 - N - the number of global subdomains requested 1471 1472 Output Parameters: 1473 + n - the number of subdomains created on this MPI rank 1474 - iis - the array of index sets defining the local inner subdomains (on which the correction is applied) 1475 1476 Level: advanced 1477 1478 Notes: 1479 When `N` >= A's communicator size, each subdomain is local -- contained within a single MPI process. 1480 When `N` < size, the subdomains are 'straddling' (rank boundaries) and are no longer local. 1481 The resulting subdomains can be use in `PCGASMSetSubdomains`(pc,n,iss,`NULL`). The overlapping 1482 outer subdomains will be automatically generated from these according to the requested amount of 1483 overlap; this is currently supported only with local subdomains. 1484 1485 Use `PCGASMDestroySubdomains()` to free the array and the list of index sets. 1486 1487 .seealso: `PCGASM`, `PCGASMSetSubdomains()`, `PCGASMDestroySubdomains()` 1488 @*/ 1489 PetscErrorCode PCGASMCreateSubdomains(Mat A, PetscInt N, PetscInt *n, IS *iis[]) 1490 { 1491 PetscMPIInt size; 1492 1493 PetscFunctionBegin; 1494 PetscValidHeaderSpecific(A, MAT_CLASSID, 1); 1495 PetscValidPointer(iis, 4); 1496 1497 PetscCheck(N >= 1, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Number of subdomains must be > 0, N = %" PetscInt_FMT, N); 1498 PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)A), &size)); 1499 if (N >= size) { 1500 *n = N / size + (N % size); 1501 PetscCall(PCGASMCreateLocalSubdomains(A, *n, iis)); 1502 } else { 1503 PetscCall(PCGASMCreateStraddlingSubdomains(A, N, n, iis)); 1504 } 1505 PetscFunctionReturn(PETSC_SUCCESS); 1506 } 1507 1508 /*@C 1509 PCGASMDestroySubdomains - Destroys the index sets created with 1510 `PCGASMCreateSubdomains()` or `PCGASMCreateSubdomains2D()`. Should be 1511 called after setting subdomains with `PCGASMSetSubdomains()`. 1512 1513 Collective 1514 1515 Input Parameters: 1516 + n - the number of index sets 1517 . iis - the array of inner subdomains 1518 - ois - the array of outer subdomains, can be `NULL` 1519 1520 Level: intermediate 1521 1522 Note: 1523 This is a convenience subroutine that walks each list, 1524 destroys each `IS` on the list, and then frees the list. At the end the 1525 list pointers are set to `NULL`. 1526 1527 .seealso: `PCGASM`, `PCGASMCreateSubdomains()`, `PCGASMSetSubdomains()`, `PCGASMSetSubdomains()` 1528 @*/ 1529 PetscErrorCode PCGASMDestroySubdomains(PetscInt n, IS **iis, IS **ois) 1530 { 1531 PetscInt i; 1532 1533 PetscFunctionBegin; 1534 if (n <= 0) PetscFunctionReturn(PETSC_SUCCESS); 1535 if (ois) { 1536 PetscValidPointer(ois, 3); 1537 if (*ois) { 1538 PetscValidPointer(*ois, 3); 1539 for (i = 0; i < n; i++) PetscCall(ISDestroy(&(*ois)[i])); 1540 PetscCall(PetscFree((*ois))); 1541 } 1542 } 1543 if (iis) { 1544 PetscValidPointer(iis, 2); 1545 if (*iis) { 1546 PetscValidPointer(*iis, 2); 1547 for (i = 0; i < n; i++) PetscCall(ISDestroy(&(*iis)[i])); 1548 PetscCall(PetscFree((*iis))); 1549 } 1550 } 1551 PetscFunctionReturn(PETSC_SUCCESS); 1552 } 1553 1554 #define PCGASMLocalSubdomainBounds2D(M, N, xleft, ylow, xright, yhigh, first, last, xleft_loc, ylow_loc, xright_loc, yhigh_loc, n) \ 1555 { \ 1556 PetscInt first_row = first / M, last_row = last / M + 1; \ 1557 /* \ 1558 Compute ylow_loc and yhigh_loc so that (ylow_loc,xleft) and (yhigh_loc,xright) are the corners \ 1559 of the bounding box of the intersection of the subdomain with the local ownership range (local \ 1560 subdomain). \ 1561 Also compute xleft_loc and xright_loc as the lower and upper bounds on the first and last rows \ 1562 of the intersection. \ 1563 */ \ 1564 /* ylow_loc is the grid row containing the first element of the local sumbdomain */ \ 1565 *ylow_loc = PetscMax(first_row, ylow); \ 1566 /* xleft_loc is the offset of first element of the local subdomain within its grid row (might actually be outside the local subdomain) */ \ 1567 *xleft_loc = *ylow_loc == first_row ? PetscMax(first % M, xleft) : xleft; \ 1568 /* yhigh_loc is the grid row above the last local subdomain element */ \ 1569 *yhigh_loc = PetscMin(last_row, yhigh); \ 1570 /* xright is the offset of the end of the local subdomain within its grid row (might actually be outside the local subdomain) */ \ 1571 *xright_loc = *yhigh_loc == last_row ? PetscMin(xright, last % M) : xright; \ 1572 /* Now compute the size of the local subdomain n. */ \ 1573 *n = 0; \ 1574 if (*ylow_loc < *yhigh_loc) { \ 1575 PetscInt width = xright - xleft; \ 1576 *n += width * (*yhigh_loc - *ylow_loc - 1); \ 1577 *n += PetscMin(PetscMax(*xright_loc - xleft, 0), width); \ 1578 *n -= PetscMin(PetscMax(*xleft_loc - xleft, 0), width); \ 1579 } \ 1580 } 1581 1582 /*@C 1583 PCGASMCreateSubdomains2D - Creates the index sets for the `PCGASM` overlapping Schwarz 1584 preconditioner for a two-dimensional problem on a regular grid. 1585 1586 Collective 1587 1588 Input Parameters: 1589 + pc - the preconditioner context 1590 . M - the global number of grid points in the x direction 1591 . N - the global number of grid points in the y direction 1592 . Mdomains - the global number of subdomains in the x direction 1593 . Ndomains - the global number of subdomains in the y direction 1594 . dof - degrees of freedom per node 1595 - overlap - overlap in mesh lines 1596 1597 Output Parameters: 1598 + Nsub - the number of local subdomains created 1599 . iis - array of index sets defining inner (nonoverlapping) subdomains 1600 - ois - array of index sets defining outer (overlapping, if overlap > 0) subdomains 1601 1602 Level: advanced 1603 1604 Note: 1605 Use `PCGASMDestroySubdomains()` to free the index sets and the arrays 1606 1607 Fortran Note: 1608 The `IS` must be declared as an array of length long enough to hold `Nsub` entries 1609 1610 .seealso: `PCGASM`, `PCGASMSetSubdomains()`, `PCGASMGetSubKSP()`, `PCGASMSetOverlap()`, `PCASMCreateSubdomains2D()`, 1611 `PCGASMDestroySubdomains()` 1612 @*/ 1613 PetscErrorCode PCGASMCreateSubdomains2D(PC pc, PetscInt M, PetscInt N, PetscInt Mdomains, PetscInt Ndomains, PetscInt dof, PetscInt overlap, PetscInt *nsub, IS **iis, IS **ois) 1614 { 1615 PetscMPIInt size, rank; 1616 PetscInt i, j; 1617 PetscInt maxheight, maxwidth; 1618 PetscInt xstart, xleft, xright, xleft_loc, xright_loc; 1619 PetscInt ystart, ylow, yhigh, ylow_loc, yhigh_loc; 1620 PetscInt x[2][2], y[2][2], n[2]; 1621 PetscInt first, last; 1622 PetscInt nidx, *idx; 1623 PetscInt ii, jj, s, q, d; 1624 PetscInt k, kk; 1625 PetscMPIInt color; 1626 MPI_Comm comm, subcomm; 1627 IS **xis = NULL, **is = ois, **is_local = iis; 1628 1629 PetscFunctionBegin; 1630 PetscCall(PetscObjectGetComm((PetscObject)pc, &comm)); 1631 PetscCallMPI(MPI_Comm_size(comm, &size)); 1632 PetscCallMPI(MPI_Comm_rank(comm, &rank)); 1633 PetscCall(MatGetOwnershipRange(pc->pmat, &first, &last)); 1634 PetscCheck((first % dof) == 0 && (last % dof) == 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, 1635 "Matrix row partitioning unsuitable for domain decomposition: local row range (%" PetscInt_FMT ",%" PetscInt_FMT ") " 1636 "does not respect the number of degrees of freedom per grid point %" PetscInt_FMT, 1637 first, last, dof); 1638 1639 /* Determine the number of domains with nonzero intersections with the local ownership range. */ 1640 s = 0; 1641 ystart = 0; 1642 for (j = 0; j < Ndomains; ++j) { 1643 maxheight = N / Ndomains + ((N % Ndomains) > j); /* Maximal height of subdomain */ 1644 PetscCheck(maxheight >= 2, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Too many %" PetscInt_FMT " subdomains in the vertical direction for mesh height %" PetscInt_FMT, Ndomains, N); 1645 /* Vertical domain limits with an overlap. */ 1646 ylow = PetscMax(ystart - overlap, 0); 1647 yhigh = PetscMin(ystart + maxheight + overlap, N); 1648 xstart = 0; 1649 for (i = 0; i < Mdomains; ++i) { 1650 maxwidth = M / Mdomains + ((M % Mdomains) > i); /* Maximal width of subdomain */ 1651 PetscCheck(maxwidth >= 2, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Too many %" PetscInt_FMT " subdomains in the horizontal direction for mesh width %" PetscInt_FMT, Mdomains, M); 1652 /* Horizontal domain limits with an overlap. */ 1653 xleft = PetscMax(xstart - overlap, 0); 1654 xright = PetscMin(xstart + maxwidth + overlap, M); 1655 /* 1656 Determine whether this subdomain intersects this rank's ownership range of pc->pmat. 1657 */ 1658 PCGASMLocalSubdomainBounds2D(M, N, xleft, ylow, xright, yhigh, first, last, (&xleft_loc), (&ylow_loc), (&xright_loc), (&yhigh_loc), (&nidx)); 1659 if (nidx) ++s; 1660 xstart += maxwidth; 1661 } /* for (i = 0; i < Mdomains; ++i) */ 1662 ystart += maxheight; 1663 } /* for (j = 0; j < Ndomains; ++j) */ 1664 1665 /* Now we can allocate the necessary number of ISs. */ 1666 *nsub = s; 1667 PetscCall(PetscMalloc1(*nsub, is)); 1668 PetscCall(PetscMalloc1(*nsub, is_local)); 1669 s = 0; 1670 ystart = 0; 1671 for (j = 0; j < Ndomains; ++j) { 1672 maxheight = N / Ndomains + ((N % Ndomains) > j); /* Maximal height of subdomain */ 1673 PetscCheck(maxheight >= 2, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Too many %" PetscInt_FMT " subdomains in the vertical direction for mesh height %" PetscInt_FMT, Ndomains, N); 1674 /* Vertical domain limits with an overlap. */ 1675 y[0][0] = PetscMax(ystart - overlap, 0); 1676 y[0][1] = PetscMin(ystart + maxheight + overlap, N); 1677 /* Vertical domain limits without an overlap. */ 1678 y[1][0] = ystart; 1679 y[1][1] = PetscMin(ystart + maxheight, N); 1680 xstart = 0; 1681 for (i = 0; i < Mdomains; ++i) { 1682 maxwidth = M / Mdomains + ((M % Mdomains) > i); /* Maximal width of subdomain */ 1683 PetscCheck(maxwidth >= 2, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Too many %" PetscInt_FMT " subdomains in the horizontal direction for mesh width %" PetscInt_FMT, Mdomains, M); 1684 /* Horizontal domain limits with an overlap. */ 1685 x[0][0] = PetscMax(xstart - overlap, 0); 1686 x[0][1] = PetscMin(xstart + maxwidth + overlap, M); 1687 /* Horizontal domain limits without an overlap. */ 1688 x[1][0] = xstart; 1689 x[1][1] = PetscMin(xstart + maxwidth, M); 1690 /* 1691 Determine whether this domain intersects this rank's ownership range of pc->pmat. 1692 Do this twice: first for the domains with overlaps, and once without. 1693 During the first pass create the subcommunicators, and use them on the second pass as well. 1694 */ 1695 for (q = 0; q < 2; ++q) { 1696 PetscBool split = PETSC_FALSE; 1697 /* 1698 domain limits, (xleft, xright) and (ylow, yheigh) are adjusted 1699 according to whether the domain with an overlap or without is considered. 1700 */ 1701 xleft = x[q][0]; 1702 xright = x[q][1]; 1703 ylow = y[q][0]; 1704 yhigh = y[q][1]; 1705 PCGASMLocalSubdomainBounds2D(M, N, xleft, ylow, xright, yhigh, first, last, (&xleft_loc), (&ylow_loc), (&xright_loc), (&yhigh_loc), (&nidx)); 1706 nidx *= dof; 1707 n[q] = nidx; 1708 /* 1709 Based on the counted number of indices in the local domain *with an overlap*, 1710 construct a subcommunicator of all the MPI ranks supporting this domain. 1711 Observe that a domain with an overlap might have nontrivial local support, 1712 while the domain without an overlap might not. Hence, the decision to participate 1713 in the subcommunicator must be based on the domain with an overlap. 1714 */ 1715 if (q == 0) { 1716 if (nidx) color = 1; 1717 else color = MPI_UNDEFINED; 1718 PetscCallMPI(MPI_Comm_split(comm, color, rank, &subcomm)); 1719 split = PETSC_TRUE; 1720 } 1721 /* 1722 Proceed only if the number of local indices *with an overlap* is nonzero. 1723 */ 1724 if (n[0]) { 1725 if (q == 0) xis = is; 1726 if (q == 1) { 1727 /* 1728 The IS for the no-overlap subdomain shares a communicator with the overlapping domain. 1729 Moreover, if the overlap is zero, the two ISs are identical. 1730 */ 1731 if (overlap == 0) { 1732 (*is_local)[s] = (*is)[s]; 1733 PetscCall(PetscObjectReference((PetscObject)(*is)[s])); 1734 continue; 1735 } else { 1736 xis = is_local; 1737 subcomm = ((PetscObject)(*is)[s])->comm; 1738 } 1739 } /* if (q == 1) */ 1740 idx = NULL; 1741 PetscCall(PetscMalloc1(nidx, &idx)); 1742 if (nidx) { 1743 k = 0; 1744 for (jj = ylow_loc; jj < yhigh_loc; ++jj) { 1745 PetscInt x0 = (jj == ylow_loc) ? xleft_loc : xleft; 1746 PetscInt x1 = (jj == yhigh_loc - 1) ? xright_loc : xright; 1747 kk = dof * (M * jj + x0); 1748 for (ii = x0; ii < x1; ++ii) { 1749 for (d = 0; d < dof; ++d) idx[k++] = kk++; 1750 } 1751 } 1752 } 1753 PetscCall(ISCreateGeneral(subcomm, nidx, idx, PETSC_OWN_POINTER, (*xis) + s)); 1754 if (split) PetscCallMPI(MPI_Comm_free(&subcomm)); 1755 } /* if (n[0]) */ 1756 } /* for (q = 0; q < 2; ++q) */ 1757 if (n[0]) ++s; 1758 xstart += maxwidth; 1759 } /* for (i = 0; i < Mdomains; ++i) */ 1760 ystart += maxheight; 1761 } /* for (j = 0; j < Ndomains; ++j) */ 1762 PetscFunctionReturn(PETSC_SUCCESS); 1763 } 1764 1765 /*@C 1766 PCGASMGetSubdomains - Gets the subdomains supported on this MPI rank 1767 for the `PCGASM` additive Schwarz preconditioner. 1768 1769 Not Collective 1770 1771 Input Parameter: 1772 . pc - the preconditioner context 1773 1774 Output Parameters: 1775 + n - the number of subdomains for this MPI rank (default value = 1) 1776 . iis - the index sets that define the inner subdomains (without overlap) supported on this rank (can be `NULL`) 1777 - ois - the index sets that define the outer subdomains (with overlap) supported on this rank (can be `NULL`) 1778 1779 Level: advanced 1780 1781 Notes: 1782 The user is responsible for destroying the `IS`s and freeing the returned arrays, this can be done with 1783 `PCGASMDestroySubdomains()` 1784 1785 The `IS` numbering is in the parallel, global numbering of the vector. 1786 1787 .seealso: `PCGASM`, `PCGASMSetOverlap()`, `PCGASMGetSubKSP()`, `PCGASMCreateSubdomains2D()`, 1788 `PCGASMSetSubdomains()`, `PCGASMGetSubmatrices()`, `PCGASMDestroySubdomains()` 1789 @*/ 1790 PetscErrorCode PCGASMGetSubdomains(PC pc, PetscInt *n, IS *iis[], IS *ois[]) 1791 { 1792 PC_GASM *osm; 1793 PetscBool match; 1794 PetscInt i; 1795 1796 PetscFunctionBegin; 1797 PetscValidHeaderSpecific(pc, PC_CLASSID, 1); 1798 PetscCall(PetscObjectTypeCompare((PetscObject)pc, PCGASM, &match)); 1799 PetscCheck(match, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONG, "Incorrect object type: expected %s, got %s instead", PCGASM, ((PetscObject)pc)->type_name); 1800 osm = (PC_GASM *)pc->data; 1801 if (n) *n = osm->n; 1802 if (iis) PetscCall(PetscMalloc1(osm->n, iis)); 1803 if (ois) PetscCall(PetscMalloc1(osm->n, ois)); 1804 if (iis || ois) { 1805 for (i = 0; i < osm->n; ++i) { 1806 if (iis) (*iis)[i] = osm->iis[i]; 1807 if (ois) (*ois)[i] = osm->ois[i]; 1808 } 1809 } 1810 PetscFunctionReturn(PETSC_SUCCESS); 1811 } 1812 1813 /*@C 1814 PCGASMGetSubmatrices - Gets the local submatrices (for this MPI rank 1815 only) for the `PCGASM` additive Schwarz preconditioner. 1816 1817 Not Collective 1818 1819 Input Parameter: 1820 . pc - the preconditioner context 1821 1822 Output Parameters: 1823 + n - the number of matrices for this MPI rank (default value = 1) 1824 - mat - the matrices 1825 1826 Level: advanced 1827 1828 Note: 1829 Matrices returned by this routine have the same communicators as the index sets (`IS`) 1830 used to define subdomains in `PCGASMSetSubdomains()` 1831 1832 .seealso: `PCGASM`, `PCGASMSetOverlap()`, `PCGASMGetSubKSP()`, 1833 `PCGASMCreateSubdomains2D()`, `PCGASMSetSubdomains()`, `PCGASMGetSubdomains()` 1834 @*/ 1835 PetscErrorCode PCGASMGetSubmatrices(PC pc, PetscInt *n, Mat *mat[]) 1836 { 1837 PC_GASM *osm; 1838 PetscBool match; 1839 1840 PetscFunctionBegin; 1841 PetscValidHeaderSpecific(pc, PC_CLASSID, 1); 1842 PetscValidIntPointer(n, 2); 1843 if (mat) PetscValidPointer(mat, 3); 1844 PetscCheck(pc->setupcalled, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONGSTATE, "Must call after KSPSetUp() or PCSetUp()."); 1845 PetscCall(PetscObjectTypeCompare((PetscObject)pc, PCGASM, &match)); 1846 PetscCheck(match, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONG, "Expected %s, got %s instead", PCGASM, ((PetscObject)pc)->type_name); 1847 osm = (PC_GASM *)pc->data; 1848 if (n) *n = osm->n; 1849 if (mat) *mat = osm->pmat; 1850 PetscFunctionReturn(PETSC_SUCCESS); 1851 } 1852 1853 /*@ 1854 PCGASMSetUseDMSubdomains - Indicates whether to use `DMCreateDomainDecomposition()` to define the subdomains, whenever possible for `PCGASM` 1855 1856 Logically Collective 1857 1858 Input Parameters: 1859 + pc - the preconditioner 1860 - flg - boolean indicating whether to use subdomains defined by the `DM` 1861 1862 Options Database Key: 1863 . -pc_gasm_dm_subdomains -pc_gasm_overlap -pc_gasm_total_subdomains 1864 1865 Level: intermediate 1866 1867 Note: 1868 `PCGASMSetSubdomains()`, `PCGASMSetTotalSubdomains()` or `PCGASMSetOverlap()` take precedence over `PCGASMSetUseDMSubdomains()`, 1869 so setting `PCGASMSetSubdomains()` with nontrivial subdomain ISs or any of `PCGASMSetTotalSubdomains()` and `PCGASMSetOverlap()` 1870 automatically turns the latter off. 1871 1872 .seealso: `PCGASM`, `PCGASMGetUseDMSubdomains()`, `PCGASMSetSubdomains()`, `PCGASMSetOverlap()` 1873 `PCGASMCreateSubdomains2D()` 1874 @*/ 1875 PetscErrorCode PCGASMSetUseDMSubdomains(PC pc, PetscBool flg) 1876 { 1877 PC_GASM *osm = (PC_GASM *)pc->data; 1878 PetscBool match; 1879 1880 PetscFunctionBegin; 1881 PetscValidHeaderSpecific(pc, PC_CLASSID, 1); 1882 PetscValidLogicalCollectiveBool(pc, flg, 2); 1883 PetscCheck(!pc->setupcalled, ((PetscObject)pc)->comm, PETSC_ERR_ARG_WRONGSTATE, "Not for a setup PC."); 1884 PetscCall(PetscObjectTypeCompare((PetscObject)pc, PCGASM, &match)); 1885 if (match) { 1886 if (!osm->user_subdomains && osm->N == PETSC_DETERMINE && osm->overlap < 0) osm->dm_subdomains = flg; 1887 } 1888 PetscFunctionReturn(PETSC_SUCCESS); 1889 } 1890 1891 /*@ 1892 PCGASMGetUseDMSubdomains - Returns flag indicating whether to use `DMCreateDomainDecomposition()` to define the subdomains, whenever possible with `PCGASM` 1893 1894 Not Collective 1895 1896 Input Parameter: 1897 . pc - the preconditioner 1898 1899 Output Parameter: 1900 . flg - boolean indicating whether to use subdomains defined by the `DM` 1901 1902 Level: intermediate 1903 1904 .seealso: `PCGASM`, `PCGASMSetUseDMSubdomains()`, `PCGASMSetOverlap()` 1905 `PCGASMCreateSubdomains2D()` 1906 @*/ 1907 PetscErrorCode PCGASMGetUseDMSubdomains(PC pc, PetscBool *flg) 1908 { 1909 PC_GASM *osm = (PC_GASM *)pc->data; 1910 PetscBool match; 1911 1912 PetscFunctionBegin; 1913 PetscValidHeaderSpecific(pc, PC_CLASSID, 1); 1914 PetscValidBoolPointer(flg, 2); 1915 PetscCall(PetscObjectTypeCompare((PetscObject)pc, PCGASM, &match)); 1916 if (match) { 1917 if (flg) *flg = osm->dm_subdomains; 1918 } 1919 PetscFunctionReturn(PETSC_SUCCESS); 1920 } 1921