1 /* 2 This file defines an "generalized" additive Schwarz preconditioner for any Mat implementation. 3 In this version, each MPI process may intersect multiple subdomains and any subdomain may 4 intersect multiple MPI processes. Intersections of subdomains with MPI processes 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 process (set in `PCGASMSetSubdomains()` or calculated in `PCGASMSetTotalSubdomains()`) 9 nmax - maximum number of local subdomains per process (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 >= -1 && 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 64 /* Inner subdomains. */ 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 PetscCall(PetscViewerASCIIPrintf(viewer, "Inner subdomain:\n")); 72 PetscCall(PetscViewerFlush(viewer)); 73 PetscCall(PetscViewerASCIIPushSynchronized(viewer)); 74 if (i > -1) { 75 PetscCall(ISGetLocalSize(osm->iis[i], &nidx)); 76 PetscCall(PetscMalloc1(16 * (nidx + 1) + 1, &cidx)); 77 PetscCall(PetscViewerStringOpen(PETSC_COMM_SELF, cidx, 16 * (nidx + 1) + 1, &sviewer)); 78 PetscCall(ISGetIndices(osm->iis[i], &idx)); 79 for (j = 0; j < nidx; ++j) PetscCall(PetscViewerStringSPrintf(sviewer, "%" PetscInt_FMT " ", idx[j])); 80 PetscCall(ISRestoreIndices(osm->iis[i], &idx)); 81 PetscCall(PetscViewerDestroy(&sviewer)); 82 PetscCall(PetscViewerASCIISynchronizedPrintf(viewer, "%s", cidx)); 83 PetscCall(PetscFree(cidx)); 84 } 85 PetscCall(PetscViewerFlush(viewer)); 86 PetscCall(PetscViewerASCIIPopSynchronized(viewer)); 87 PetscCall(PetscViewerASCIIPrintf(viewer, "\n")); 88 PetscCall(PetscViewerFlush(viewer)); 89 90 /* Outer subdomains. */ 91 /* 92 No more than 15 characters per index plus a space. 93 PetscViewerStringSPrintf requires a string of size at least 2, so use (nidx+1) instead of nidx, 94 in case nidx == 0. That will take care of the space for the trailing '\0' as well. 95 For nidx == 0, the whole string 16 '\0'. 96 */ 97 PetscCall(PetscViewerASCIIPrintf(viewer, "Outer subdomain:\n")); 98 PetscCall(PetscViewerFlush(viewer)); 99 PetscCall(PetscViewerASCIIPushSynchronized(viewer)); 100 if (i > -1) { 101 PetscCall(ISGetLocalSize(osm->ois[i], &nidx)); 102 PetscCall(PetscMalloc1(16 * (nidx + 1) + 1, &cidx)); 103 PetscCall(PetscViewerStringOpen(PETSC_COMM_SELF, cidx, 16 * (nidx + 1) + 1, &sviewer)); 104 PetscCall(ISGetIndices(osm->ois[i], &idx)); 105 for (j = 0; j < nidx; ++j) PetscCall(PetscViewerStringSPrintf(sviewer, "%" PetscInt_FMT " ", idx[j])); 106 PetscCall(PetscViewerDestroy(&sviewer)); 107 PetscCall(ISRestoreIndices(osm->ois[i], &idx)); 108 PetscCall(PetscViewerASCIISynchronizedPrintf(viewer, "%s", cidx)); 109 PetscCall(PetscFree(cidx)); 110 } 111 PetscCall(PetscViewerFlush(viewer)); 112 PetscCall(PetscViewerASCIIPopSynchronized(viewer)); 113 PetscCall(PetscViewerASCIIPrintf(viewer, "\n")); 114 PetscCall(PetscViewerFlush(viewer)); 115 PetscFunctionReturn(PETSC_SUCCESS); 116 } 117 118 static PetscErrorCode PCGASMPrintSubdomains(PC pc) 119 { 120 PC_GASM *osm = (PC_GASM *)pc->data; 121 const char *prefix; 122 char fname[PETSC_MAX_PATH_LEN + 1]; 123 PetscInt l, d, count; 124 PetscBool found; 125 PetscViewer viewer; 126 PetscInt *numbering, *permutation; /* global numbering of locally-supported subdomains and the permutation from the local ordering */ 127 128 PetscFunctionBegin; 129 PetscCall(PCGetOptionsPrefix(pc, &prefix)); 130 PetscCall(PetscOptionsHasName(NULL, prefix, "-pc_gasm_print_subdomains", &found)); 131 if (!found) PetscFunctionReturn(PETSC_SUCCESS); 132 PetscCall(PetscOptionsGetString(NULL, prefix, "-pc_gasm_print_subdomains", fname, sizeof(fname), &found)); 133 if (!found) PetscCall(PetscStrncpy(fname, "stdout", sizeof(fname))); 134 PetscCall(PetscViewerASCIIOpen(PetscObjectComm((PetscObject)pc), fname, &viewer)); 135 /* 136 Make sure the viewer has a name. Otherwise this may cause a deadlock or other weird errors when creating a subcomm viewer: 137 the subcomm viewer will attempt to inherit the viewer's name, which, if not set, will be constructed collectively on the comm. 138 */ 139 PetscCall(PetscObjectName((PetscObject)viewer)); 140 l = 0; 141 PetscCall(PCGASMComputeGlobalSubdomainNumbering_Private(pc, &numbering, &permutation)); 142 for (count = 0; count < osm->N; ++count) { 143 /* Now let subdomains go one at a time in the global numbering order and print their subdomain/solver info. */ 144 if (l < osm->n) { 145 d = permutation[l]; /* d is the local number of the l-th smallest (in the global ordering) among the locally supported subdomains */ 146 if (numbering[d] == count) l++; 147 else d = -1; 148 } else d = -1; 149 PetscCall(PCGASMSubdomainView_Private(pc, d, viewer)); 150 } 151 PetscCall(PetscFree2(numbering, permutation)); 152 PetscCall(PetscViewerDestroy(&viewer)); 153 PetscFunctionReturn(PETSC_SUCCESS); 154 } 155 156 static PetscErrorCode PCView_GASM(PC pc, PetscViewer viewer) 157 { 158 PC_GASM *osm = (PC_GASM *)pc->data; 159 const char *prefix; 160 PetscMPIInt rank, size; 161 PetscInt bsz; 162 PetscBool iascii, view_subdomains = PETSC_FALSE; 163 PetscViewer sviewer; 164 PetscInt count, l; 165 char overlap[256] = "user-defined overlap"; 166 char gsubdomains[256] = "unknown total number of subdomains"; 167 char msubdomains[256] = "unknown max number of local subdomains"; 168 PetscInt *numbering, *permutation; /* global numbering of locally-supported subdomains and the permutation from the local ordering */ 169 170 PetscFunctionBegin; 171 PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)pc), &size)); 172 PetscCallMPI(MPI_Comm_rank(PetscObjectComm((PetscObject)pc), &rank)); 173 174 if (osm->overlap >= 0) PetscCall(PetscSNPrintf(overlap, sizeof(overlap), "requested amount of overlap = %" PetscInt_FMT, osm->overlap)); 175 if (osm->N != PETSC_DETERMINE) PetscCall(PetscSNPrintf(gsubdomains, sizeof(gsubdomains), "total number of subdomains = %" PetscInt_FMT, osm->N)); 176 if (osm->nmax != PETSC_DETERMINE) PetscCall(PetscSNPrintf(msubdomains, sizeof(msubdomains), "max number of local subdomains = %" PetscInt_FMT, osm->nmax)); 177 178 PetscCall(PCGetOptionsPrefix(pc, &prefix)); 179 PetscCall(PetscOptionsGetBool(NULL, prefix, "-pc_gasm_view_subdomains", &view_subdomains, NULL)); 180 181 PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERASCII, &iascii)); 182 if (iascii) { 183 /* 184 Make sure the viewer has a name. Otherwise this may cause a deadlock when creating a subcomm viewer: 185 the subcomm viewer will attempt to inherit the viewer's name, which, if not set, will be constructed 186 collectively on the comm. 187 */ 188 PetscCall(PetscObjectName((PetscObject)viewer)); 189 PetscCall(PetscViewerASCIIPrintf(viewer, " Restriction/interpolation type: %s\n", PCGASMTypes[osm->type])); 190 PetscCall(PetscViewerASCIIPrintf(viewer, " %s\n", overlap)); 191 PetscCall(PetscViewerASCIIPrintf(viewer, " %s\n", gsubdomains)); 192 PetscCall(PetscViewerASCIIPrintf(viewer, " %s\n", msubdomains)); 193 PetscCall(PetscViewerASCIIPushSynchronized(viewer)); 194 PetscCall(PetscViewerASCIISynchronizedPrintf(viewer, " [%d|%d] number of locally-supported subdomains = %" PetscInt_FMT "\n", rank, size, osm->n)); 195 PetscCall(PetscViewerFlush(viewer)); 196 PetscCall(PetscViewerASCIIPopSynchronized(viewer)); 197 /* Cannot take advantage of osm->same_subdomain_solvers without a global numbering of subdomains. */ 198 PetscCall(PetscViewerASCIIPrintf(viewer, " Subdomain solver info is as follows:\n")); 199 PetscCall(PetscViewerASCIIPushTab(viewer)); 200 PetscCall(PetscViewerASCIIPrintf(viewer, " - - - - - - - - - - - - - - - - - -\n")); 201 /* Now let subdomains go one at a time in the global numbering order and print their subdomain/solver info. */ 202 PetscCall(PCGASMComputeGlobalSubdomainNumbering_Private(pc, &numbering, &permutation)); 203 l = 0; 204 for (count = 0; count < osm->N; ++count) { 205 PetscMPIInt srank, ssize; 206 if (l < osm->n) { 207 PetscInt d = permutation[l]; /* d is the local number of the l-th smallest (in the global ordering) among the locally supported subdomains */ 208 if (numbering[d] == count) { 209 PetscCallMPI(MPI_Comm_size(((PetscObject)osm->ois[d])->comm, &ssize)); 210 PetscCallMPI(MPI_Comm_rank(((PetscObject)osm->ois[d])->comm, &srank)); 211 PetscCall(PetscViewerGetSubViewer(viewer, ((PetscObject)osm->ois[d])->comm, &sviewer)); 212 PetscCall(ISGetLocalSize(osm->ois[d], &bsz)); 213 PetscCall(PetscViewerASCIISynchronizedPrintf(sviewer, " [%d|%d] (subcomm [%d|%d]) local subdomain number %" PetscInt_FMT ", local size = %" PetscInt_FMT "\n", rank, size, srank, ssize, d, bsz)); 214 PetscCall(PetscViewerFlush(sviewer)); 215 PetscCall(PetscViewerASCIIPushTab(sviewer)); 216 if (view_subdomains) PetscCall(PCGASMSubdomainView_Private(pc, d, sviewer)); 217 if (!pc->setupcalled) { 218 PetscCall(PetscViewerASCIISynchronizedPrintf(sviewer, " Solver not set up yet: PCSetUp() not yet called\n")); 219 } else { 220 PetscCall(KSPView(osm->ksp[d], sviewer)); 221 } 222 PetscCall(PetscViewerASCIIPopTab(sviewer)); 223 PetscCall(PetscViewerASCIIPrintf(sviewer, " - - - - - - - - - - - - - - - - - -\n")); 224 PetscCall(PetscViewerFlush(sviewer)); 225 PetscCall(PetscViewerRestoreSubViewer(viewer, ((PetscObject)osm->ois[d])->comm, &sviewer)); 226 ++l; 227 } else { 228 PetscCall(PetscViewerGetSubViewer(viewer, PETSC_COMM_SELF, &sviewer)); 229 PetscCall(PetscViewerRestoreSubViewer(viewer, PETSC_COMM_SELF, &sviewer)); 230 } 231 } else { 232 PetscCall(PetscViewerGetSubViewer(viewer, PETSC_COMM_SELF, &sviewer)); 233 PetscCall(PetscViewerRestoreSubViewer(viewer, PETSC_COMM_SELF, &sviewer)); 234 } 235 } 236 PetscCall(PetscFree2(numbering, permutation)); 237 PetscCall(PetscViewerASCIIPopTab(viewer)); 238 PetscCall(PetscViewerFlush(viewer)); 239 /* this line is needed to match the extra PetscViewerASCIIPushSynchronized() in PetscViewerGetSubViewer() */ 240 PetscCall(PetscViewerASCIIPopSynchronized(viewer)); 241 } 242 PetscFunctionReturn(PETSC_SUCCESS); 243 } 244 245 PETSC_INTERN PetscErrorCode PCGASMCreateLocalSubdomains(Mat A, PetscInt nloc, IS *iis[]); 246 247 static PetscErrorCode PCGASMSetHierarchicalPartitioning(PC pc) 248 { 249 PC_GASM *osm = (PC_GASM *)pc->data; 250 MatPartitioning part; 251 MPI_Comm comm; 252 PetscMPIInt size; 253 PetscInt nlocalsubdomains, fromrows_localsize; 254 IS partitioning, fromrows, isn; 255 Vec outervec; 256 257 PetscFunctionBegin; 258 PetscCall(PetscObjectGetComm((PetscObject)pc, &comm)); 259 PetscCallMPI(MPI_Comm_size(comm, &size)); 260 /* we do not need a hierarchical partitioning when 261 * the total number of subdomains is consistent with 262 * the number of MPI tasks. 263 * For the following cases, we do not need to use HP 264 * */ 265 if (osm->N == PETSC_DETERMINE || osm->N >= size || osm->N == 1) PetscFunctionReturn(PETSC_SUCCESS); 266 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); 267 nlocalsubdomains = size / osm->N; 268 osm->n = 1; 269 PetscCall(MatPartitioningCreate(comm, &part)); 270 PetscCall(MatPartitioningSetAdjacency(part, pc->pmat)); 271 PetscCall(MatPartitioningSetType(part, MATPARTITIONINGHIERARCH)); 272 PetscCall(MatPartitioningHierarchicalSetNcoarseparts(part, osm->N)); 273 PetscCall(MatPartitioningHierarchicalSetNfineparts(part, nlocalsubdomains)); 274 PetscCall(MatPartitioningSetFromOptions(part)); 275 /* get new rank owner number of each vertex */ 276 PetscCall(MatPartitioningApply(part, &partitioning)); 277 PetscCall(ISBuildTwoSided(partitioning, NULL, &fromrows)); 278 PetscCall(ISPartitioningToNumbering(partitioning, &isn)); 279 PetscCall(ISDestroy(&isn)); 280 PetscCall(ISGetLocalSize(fromrows, &fromrows_localsize)); 281 PetscCall(MatPartitioningDestroy(&part)); 282 PetscCall(MatCreateVecs(pc->pmat, &outervec, NULL)); 283 PetscCall(VecCreateMPI(comm, fromrows_localsize, PETSC_DETERMINE, &osm->pcx)); 284 PetscCall(VecDuplicate(osm->pcx, &osm->pcy)); 285 PetscCall(VecScatterCreate(osm->pcx, NULL, outervec, fromrows, &osm->pctoouter)); 286 PetscCall(MatCreateSubMatrix(pc->pmat, fromrows, fromrows, MAT_INITIAL_MATRIX, &osm->permutationP)); 287 PetscCall(PetscObjectReference((PetscObject)fromrows)); 288 osm->permutationIS = fromrows; 289 osm->pcmat = pc->pmat; 290 PetscCall(PetscObjectReference((PetscObject)osm->permutationP)); 291 pc->pmat = osm->permutationP; 292 PetscCall(VecDestroy(&outervec)); 293 PetscCall(ISDestroy(&fromrows)); 294 PetscCall(ISDestroy(&partitioning)); 295 osm->n = PETSC_DETERMINE; 296 PetscFunctionReturn(PETSC_SUCCESS); 297 } 298 299 static PetscErrorCode PCSetUp_GASM(PC pc) 300 { 301 PC_GASM *osm = (PC_GASM *)pc->data; 302 PetscInt i, nInnerIndices, nTotalInnerIndices; 303 PetscMPIInt rank, size; 304 MatReuse scall = MAT_REUSE_MATRIX; 305 KSP ksp; 306 PC subpc; 307 const char *prefix, *pprefix; 308 Vec x, y; 309 PetscInt oni; /* Number of indices in the i-th local outer subdomain. */ 310 const PetscInt *oidxi; /* Indices from the i-th subdomain local outer subdomain. */ 311 PetscInt on; /* Number of indices in the disjoint union of local outer subdomains. */ 312 PetscInt *oidx; /* Indices in the disjoint union of local outer subdomains. */ 313 IS gois; /* Disjoint union the global indices of outer subdomains. */ 314 IS goid; /* Identity IS of the size of the disjoint union of outer subdomains. */ 315 PetscScalar *gxarray, *gyarray; 316 PetscInt gostart; /* Start of locally-owned indices in the vectors -- osm->gx,osm->gy -- over the disjoint union of outer subdomains. */ 317 PetscInt num_subdomains = 0; 318 DM *subdomain_dm = NULL; 319 char **subdomain_names = NULL; 320 PetscInt *numbering; 321 322 PetscFunctionBegin; 323 PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)pc), &size)); 324 PetscCallMPI(MPI_Comm_rank(PetscObjectComm((PetscObject)pc), &rank)); 325 if (!pc->setupcalled) { 326 /* use a hierarchical partitioning */ 327 if (osm->hierarchicalpartitioning) PetscCall(PCGASMSetHierarchicalPartitioning(pc)); 328 if (osm->n == PETSC_DETERMINE) { 329 if (osm->N != PETSC_DETERMINE) { 330 /* No local subdomains given, but the desired number of total subdomains is known, so construct them accordingly. */ 331 PetscCall(PCGASMCreateSubdomains(pc->pmat, osm->N, &osm->n, &osm->iis)); 332 } else if (osm->dm_subdomains && pc->dm) { 333 /* try pc->dm next, if allowed */ 334 PetscInt d; 335 IS *inner_subdomain_is, *outer_subdomain_is; 336 PetscCall(DMCreateDomainDecomposition(pc->dm, &num_subdomains, &subdomain_names, &inner_subdomain_is, &outer_subdomain_is, &subdomain_dm)); 337 if (num_subdomains) PetscCall(PCGASMSetSubdomains(pc, num_subdomains, inner_subdomain_is, outer_subdomain_is)); 338 for (d = 0; d < num_subdomains; ++d) { 339 if (inner_subdomain_is) PetscCall(ISDestroy(&inner_subdomain_is[d])); 340 if (outer_subdomain_is) PetscCall(ISDestroy(&outer_subdomain_is[d])); 341 } 342 PetscCall(PetscFree(inner_subdomain_is)); 343 PetscCall(PetscFree(outer_subdomain_is)); 344 } else { 345 /* still no subdomains; use one per rank */ 346 osm->nmax = osm->n = 1; 347 PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)pc), &size)); 348 osm->N = size; 349 PetscCall(PCGASMCreateLocalSubdomains(pc->pmat, osm->n, &osm->iis)); 350 } 351 } 352 if (!osm->iis) { 353 /* 354 osm->n was set in PCGASMSetSubdomains(), but the actual subdomains have not been supplied. 355 We create the requisite number of local inner subdomains and then expand them into 356 out subdomains, if necessary. 357 */ 358 PetscCall(PCGASMCreateLocalSubdomains(pc->pmat, osm->n, &osm->iis)); 359 } 360 if (!osm->ois) { 361 /* 362 Initially make outer subdomains the same as inner subdomains. If nonzero additional overlap 363 has been requested, copy the inner subdomains over so they can be modified. 364 */ 365 PetscCall(PetscMalloc1(osm->n, &osm->ois)); 366 for (i = 0; i < osm->n; ++i) { 367 if (osm->overlap > 0 && osm->N > 1) { /* With positive overlap, osm->iis[i] will be modified */ 368 PetscCall(ISDuplicate(osm->iis[i], (osm->ois) + i)); 369 PetscCall(ISCopy(osm->iis[i], osm->ois[i])); 370 } else { 371 PetscCall(PetscObjectReference((PetscObject)osm->iis[i])); 372 osm->ois[i] = osm->iis[i]; 373 } 374 } 375 if (osm->overlap > 0 && osm->N > 1) { 376 /* Extend the "overlapping" regions by a number of steps */ 377 PetscCall(MatIncreaseOverlapSplit(pc->pmat, osm->n, osm->ois, osm->overlap)); 378 } 379 } 380 381 /* Now the subdomains are defined. Determine their global and max local numbers, if necessary. */ 382 if (osm->nmax == PETSC_DETERMINE) { 383 PetscInt inwork, outwork; 384 /* determine global number of subdomains and the max number of local subdomains */ 385 inwork = osm->n; 386 PetscCallMPI(MPIU_Allreduce(&inwork, &outwork, 1, MPIU_INT, MPI_MAX, PetscObjectComm((PetscObject)pc))); 387 osm->nmax = outwork; 388 } 389 if (osm->N == PETSC_DETERMINE) { 390 /* Determine the number of globally-distinct subdomains and compute a global numbering for them. */ 391 PetscCall(PetscObjectsListGetGlobalNumbering(PetscObjectComm((PetscObject)pc), osm->n, (PetscObject *)osm->ois, &osm->N, NULL)); 392 } 393 394 if (osm->sort_indices) { 395 for (i = 0; i < osm->n; i++) { 396 PetscCall(ISSort(osm->ois[i])); 397 PetscCall(ISSort(osm->iis[i])); 398 } 399 } 400 PetscCall(PCGetOptionsPrefix(pc, &prefix)); 401 PetscCall(PCGASMPrintSubdomains(pc)); 402 403 /* 404 Merge the ISs, create merged vectors and restrictions. 405 */ 406 /* Merge outer subdomain ISs and construct a restriction onto the disjoint union of local outer subdomains. */ 407 on = 0; 408 for (i = 0; i < osm->n; i++) { 409 PetscCall(ISGetLocalSize(osm->ois[i], &oni)); 410 on += oni; 411 } 412 PetscCall(PetscMalloc1(on, &oidx)); 413 on = 0; 414 /* Merge local indices together */ 415 for (i = 0; i < osm->n; i++) { 416 PetscCall(ISGetLocalSize(osm->ois[i], &oni)); 417 PetscCall(ISGetIndices(osm->ois[i], &oidxi)); 418 PetscCall(PetscArraycpy(oidx + on, oidxi, oni)); 419 PetscCall(ISRestoreIndices(osm->ois[i], &oidxi)); 420 on += oni; 421 } 422 PetscCall(ISCreateGeneral(((PetscObject)pc)->comm, on, oidx, PETSC_OWN_POINTER, &gois)); 423 nTotalInnerIndices = 0; 424 for (i = 0; i < osm->n; i++) { 425 PetscCall(ISGetLocalSize(osm->iis[i], &nInnerIndices)); 426 nTotalInnerIndices += nInnerIndices; 427 } 428 PetscCall(VecCreateMPI(((PetscObject)pc)->comm, nTotalInnerIndices, PETSC_DETERMINE, &x)); 429 PetscCall(VecDuplicate(x, &y)); 430 431 PetscCall(VecCreateMPI(PetscObjectComm((PetscObject)pc), on, PETSC_DECIDE, &osm->gx)); 432 PetscCall(VecDuplicate(osm->gx, &osm->gy)); 433 PetscCall(VecGetOwnershipRange(osm->gx, &gostart, NULL)); 434 PetscCall(ISCreateStride(PetscObjectComm((PetscObject)pc), on, gostart, 1, &goid)); 435 /* gois might indices not on local */ 436 PetscCall(VecScatterCreate(x, gois, osm->gx, goid, &osm->gorestriction)); 437 PetscCall(PetscMalloc1(osm->n, &numbering)); 438 PetscCall(PetscObjectsListGetGlobalNumbering(PetscObjectComm((PetscObject)pc), osm->n, (PetscObject *)osm->ois, NULL, numbering)); 439 PetscCall(VecDestroy(&x)); 440 PetscCall(ISDestroy(&gois)); 441 442 /* Merge inner subdomain ISs and construct a restriction onto the disjoint union of local inner subdomains. */ 443 { 444 PetscInt ini; /* Number of indices the i-th a local inner subdomain. */ 445 PetscInt in; /* Number of indices in the disjoint union of local inner subdomains. */ 446 PetscInt *iidx; /* Global indices in the merged local inner subdomain. */ 447 PetscInt *ioidx; /* Global indices of the disjoint union of inner subdomains within the disjoint union of outer subdomains. */ 448 IS giis; /* IS for the disjoint union of inner subdomains. */ 449 IS giois; /* IS for the disjoint union of inner subdomains within the disjoint union of outer subdomains. */ 450 PetscScalar *array; 451 const PetscInt *indices; 452 PetscInt k; 453 on = 0; 454 for (i = 0; i < osm->n; i++) { 455 PetscCall(ISGetLocalSize(osm->ois[i], &oni)); 456 on += oni; 457 } 458 PetscCall(PetscMalloc1(on, &iidx)); 459 PetscCall(PetscMalloc1(on, &ioidx)); 460 PetscCall(VecGetArray(y, &array)); 461 /* set communicator id to determine where overlap is */ 462 in = 0; 463 for (i = 0; i < osm->n; i++) { 464 PetscCall(ISGetLocalSize(osm->iis[i], &ini)); 465 for (k = 0; k < ini; ++k) array[in + k] = numbering[i]; 466 in += ini; 467 } 468 PetscCall(VecRestoreArray(y, &array)); 469 PetscCall(VecScatterBegin(osm->gorestriction, y, osm->gy, INSERT_VALUES, SCATTER_FORWARD)); 470 PetscCall(VecScatterEnd(osm->gorestriction, y, osm->gy, INSERT_VALUES, SCATTER_FORWARD)); 471 PetscCall(VecGetOwnershipRange(osm->gy, &gostart, NULL)); 472 PetscCall(VecGetArray(osm->gy, &array)); 473 on = 0; 474 in = 0; 475 for (i = 0; i < osm->n; i++) { 476 PetscCall(ISGetLocalSize(osm->ois[i], &oni)); 477 PetscCall(ISGetIndices(osm->ois[i], &indices)); 478 for (k = 0; k < oni; k++) { 479 /* skip overlapping indices to get inner domain */ 480 if (PetscRealPart(array[on + k]) != numbering[i]) continue; 481 iidx[in] = indices[k]; 482 ioidx[in++] = gostart + on + k; 483 } 484 PetscCall(ISRestoreIndices(osm->ois[i], &indices)); 485 on += oni; 486 } 487 PetscCall(VecRestoreArray(osm->gy, &array)); 488 PetscCall(ISCreateGeneral(PetscObjectComm((PetscObject)pc), in, iidx, PETSC_OWN_POINTER, &giis)); 489 PetscCall(ISCreateGeneral(PetscObjectComm((PetscObject)pc), in, ioidx, PETSC_OWN_POINTER, &giois)); 490 PetscCall(VecScatterCreate(y, giis, osm->gy, giois, &osm->girestriction)); 491 PetscCall(VecDestroy(&y)); 492 PetscCall(ISDestroy(&giis)); 493 PetscCall(ISDestroy(&giois)); 494 } 495 PetscCall(ISDestroy(&goid)); 496 PetscCall(PetscFree(numbering)); 497 498 /* Create the subdomain work vectors. */ 499 PetscCall(PetscMalloc1(osm->n, &osm->x)); 500 PetscCall(PetscMalloc1(osm->n, &osm->y)); 501 PetscCall(VecGetArray(osm->gx, &gxarray)); 502 PetscCall(VecGetArray(osm->gy, &gyarray)); 503 for (i = 0, on = 0; i < osm->n; ++i, on += oni) { 504 PetscInt oNi; 505 PetscCall(ISGetLocalSize(osm->ois[i], &oni)); 506 /* on a sub communicator */ 507 PetscCall(ISGetSize(osm->ois[i], &oNi)); 508 PetscCall(VecCreateMPIWithArray(((PetscObject)osm->ois[i])->comm, 1, oni, oNi, gxarray + on, &osm->x[i])); 509 PetscCall(VecCreateMPIWithArray(((PetscObject)osm->ois[i])->comm, 1, oni, oNi, gyarray + on, &osm->y[i])); 510 } 511 PetscCall(VecRestoreArray(osm->gx, &gxarray)); 512 PetscCall(VecRestoreArray(osm->gy, &gyarray)); 513 /* Create the subdomain solvers */ 514 PetscCall(PetscMalloc1(osm->n, &osm->ksp)); 515 for (i = 0; i < osm->n; i++) { 516 char subprefix[PETSC_MAX_PATH_LEN + 1]; 517 PetscCall(KSPCreate(((PetscObject)osm->ois[i])->comm, &ksp)); 518 PetscCall(KSPSetNestLevel(ksp, pc->kspnestlevel)); 519 PetscCall(KSPSetErrorIfNotConverged(ksp, pc->erroriffailure)); 520 PetscCall(PetscObjectIncrementTabLevel((PetscObject)ksp, (PetscObject)pc, 1)); 521 PetscCall(KSPSetType(ksp, KSPPREONLY)); 522 PetscCall(KSPGetPC(ksp, &subpc)); /* Why do we need this here? */ 523 if (subdomain_dm) { 524 PetscCall(KSPSetDM(ksp, subdomain_dm[i])); 525 PetscCall(DMDestroy(subdomain_dm + i)); 526 } 527 PetscCall(PCGetOptionsPrefix(pc, &prefix)); 528 PetscCall(KSPSetOptionsPrefix(ksp, prefix)); 529 if (subdomain_names && subdomain_names[i]) { 530 PetscCall(PetscSNPrintf(subprefix, PETSC_MAX_PATH_LEN, "sub_%s_", subdomain_names[i])); 531 PetscCall(KSPAppendOptionsPrefix(ksp, subprefix)); 532 PetscCall(PetscFree(subdomain_names[i])); 533 } 534 PetscCall(KSPAppendOptionsPrefix(ksp, "sub_")); 535 osm->ksp[i] = ksp; 536 } 537 PetscCall(PetscFree(subdomain_dm)); 538 PetscCall(PetscFree(subdomain_names)); 539 scall = MAT_INITIAL_MATRIX; 540 } else { /* if (pc->setupcalled) */ 541 /* 542 Destroy the submatrices from the previous iteration 543 */ 544 if (pc->flag == DIFFERENT_NONZERO_PATTERN) { 545 PetscCall(MatDestroyMatrices(osm->n, &osm->pmat)); 546 scall = MAT_INITIAL_MATRIX; 547 } 548 if (osm->permutationIS) { 549 PetscCall(MatCreateSubMatrix(pc->pmat, osm->permutationIS, osm->permutationIS, scall, &osm->permutationP)); 550 PetscCall(PetscObjectReference((PetscObject)osm->permutationP)); 551 osm->pcmat = pc->pmat; 552 pc->pmat = osm->permutationP; 553 } 554 } 555 556 /* 557 Extract the submatrices. 558 */ 559 if (size > 1) { 560 PetscCall(MatCreateSubMatricesMPI(pc->pmat, osm->n, osm->ois, osm->ois, scall, &osm->pmat)); 561 } else { 562 PetscCall(MatCreateSubMatrices(pc->pmat, osm->n, osm->ois, osm->ois, scall, &osm->pmat)); 563 } 564 if (scall == MAT_INITIAL_MATRIX) { 565 PetscCall(PetscObjectGetOptionsPrefix((PetscObject)pc->pmat, &pprefix)); 566 for (i = 0; i < osm->n; i++) PetscCall(PetscObjectSetOptionsPrefix((PetscObject)osm->pmat[i], pprefix)); 567 } 568 569 /* Return control to the user so that the submatrices can be modified (e.g., to apply 570 different boundary conditions for the submatrices than for the global problem) */ 571 PetscCall(PCModifySubMatrices(pc, osm->n, osm->ois, osm->ois, osm->pmat, pc->modifysubmatricesP)); 572 573 /* 574 Loop over submatrices putting them into local ksps 575 */ 576 for (i = 0; i < osm->n; i++) { 577 PetscCall(KSPSetOperators(osm->ksp[i], osm->pmat[i], osm->pmat[i])); 578 PetscCall(KSPGetOptionsPrefix(osm->ksp[i], &prefix)); 579 PetscCall(MatSetOptionsPrefix(osm->pmat[i], prefix)); 580 if (!pc->setupcalled) PetscCall(KSPSetFromOptions(osm->ksp[i])); 581 } 582 if (osm->pcmat) { 583 PetscCall(MatDestroy(&pc->pmat)); 584 pc->pmat = osm->pcmat; 585 osm->pcmat = NULL; 586 } 587 PetscFunctionReturn(PETSC_SUCCESS); 588 } 589 590 static PetscErrorCode PCSetUpOnBlocks_GASM(PC pc) 591 { 592 PC_GASM *osm = (PC_GASM *)pc->data; 593 PetscInt i; 594 595 PetscFunctionBegin; 596 for (i = 0; i < osm->n; i++) PetscCall(KSPSetUp(osm->ksp[i])); 597 PetscFunctionReturn(PETSC_SUCCESS); 598 } 599 600 static PetscErrorCode PCApply_GASM(PC pc, Vec xin, Vec yout) 601 { 602 PC_GASM *osm = (PC_GASM *)pc->data; 603 PetscInt i; 604 Vec x, y; 605 ScatterMode forward = SCATTER_FORWARD, reverse = SCATTER_REVERSE; 606 607 PetscFunctionBegin; 608 if (osm->pctoouter) { 609 PetscCall(VecScatterBegin(osm->pctoouter, xin, osm->pcx, INSERT_VALUES, SCATTER_REVERSE)); 610 PetscCall(VecScatterEnd(osm->pctoouter, xin, osm->pcx, INSERT_VALUES, SCATTER_REVERSE)); 611 x = osm->pcx; 612 y = osm->pcy; 613 } else { 614 x = xin; 615 y = yout; 616 } 617 /* 618 support for limiting the restriction or interpolation only to the inner 619 subdomain values (leaving the other values 0). 620 */ 621 if (!(osm->type & PC_GASM_RESTRICT)) { 622 /* have to zero the work RHS since scatter may leave some slots empty */ 623 PetscCall(VecZeroEntries(osm->gx)); 624 PetscCall(VecScatterBegin(osm->girestriction, x, osm->gx, INSERT_VALUES, forward)); 625 } else { 626 PetscCall(VecScatterBegin(osm->gorestriction, x, osm->gx, INSERT_VALUES, forward)); 627 } 628 PetscCall(VecZeroEntries(osm->gy)); 629 if (!(osm->type & PC_GASM_RESTRICT)) { 630 PetscCall(VecScatterEnd(osm->girestriction, x, osm->gx, INSERT_VALUES, forward)); 631 } else { 632 PetscCall(VecScatterEnd(osm->gorestriction, x, osm->gx, INSERT_VALUES, forward)); 633 } 634 /* do the subdomain solves */ 635 for (i = 0; i < osm->n; ++i) { 636 PetscCall(KSPSolve(osm->ksp[i], osm->x[i], osm->y[i])); 637 PetscCall(KSPCheckSolve(osm->ksp[i], pc, osm->y[i])); 638 } 639 /* do we need to zero y? */ 640 PetscCall(VecZeroEntries(y)); 641 if (!(osm->type & PC_GASM_INTERPOLATE)) { 642 PetscCall(VecScatterBegin(osm->girestriction, osm->gy, y, ADD_VALUES, reverse)); 643 PetscCall(VecScatterEnd(osm->girestriction, osm->gy, y, ADD_VALUES, reverse)); 644 } else { 645 PetscCall(VecScatterBegin(osm->gorestriction, osm->gy, y, ADD_VALUES, reverse)); 646 PetscCall(VecScatterEnd(osm->gorestriction, osm->gy, y, ADD_VALUES, reverse)); 647 } 648 if (osm->pctoouter) { 649 PetscCall(VecScatterBegin(osm->pctoouter, y, yout, INSERT_VALUES, SCATTER_FORWARD)); 650 PetscCall(VecScatterEnd(osm->pctoouter, y, yout, INSERT_VALUES, SCATTER_FORWARD)); 651 } 652 PetscFunctionReturn(PETSC_SUCCESS); 653 } 654 655 static PetscErrorCode PCMatApply_GASM(PC pc, Mat Xin, Mat Yout) 656 { 657 PC_GASM *osm = (PC_GASM *)pc->data; 658 Mat X, Y, O = NULL, Z, W; 659 Vec x, y; 660 PetscInt i, m, M, N; 661 ScatterMode forward = SCATTER_FORWARD, reverse = SCATTER_REVERSE; 662 663 PetscFunctionBegin; 664 PetscCheck(osm->n == 1, PetscObjectComm((PetscObject)pc), PETSC_ERR_SUP, "Not yet implemented"); 665 PetscCall(MatGetSize(Xin, NULL, &N)); 666 if (osm->pctoouter) { 667 PetscCall(VecGetLocalSize(osm->pcx, &m)); 668 PetscCall(VecGetSize(osm->pcx, &M)); 669 PetscCall(MatCreateDense(PetscObjectComm((PetscObject)osm->ois[0]), m, PETSC_DECIDE, M, N, NULL, &O)); 670 for (i = 0; i < N; ++i) { 671 PetscCall(MatDenseGetColumnVecRead(Xin, i, &x)); 672 PetscCall(MatDenseGetColumnVecWrite(O, i, &y)); 673 PetscCall(VecScatterBegin(osm->pctoouter, x, y, INSERT_VALUES, SCATTER_REVERSE)); 674 PetscCall(VecScatterEnd(osm->pctoouter, x, y, INSERT_VALUES, SCATTER_REVERSE)); 675 PetscCall(MatDenseRestoreColumnVecWrite(O, i, &y)); 676 PetscCall(MatDenseRestoreColumnVecRead(Xin, i, &x)); 677 } 678 X = Y = O; 679 } else { 680 X = Xin; 681 Y = Yout; 682 } 683 /* 684 support for limiting the restriction or interpolation only to the inner 685 subdomain values (leaving the other values 0). 686 */ 687 PetscCall(VecGetLocalSize(osm->x[0], &m)); 688 PetscCall(VecGetSize(osm->x[0], &M)); 689 PetscCall(MatCreateDense(PetscObjectComm((PetscObject)osm->ois[0]), m, PETSC_DECIDE, M, N, NULL, &Z)); 690 for (i = 0; i < N; ++i) { 691 PetscCall(MatDenseGetColumnVecRead(X, i, &x)); 692 PetscCall(MatDenseGetColumnVecWrite(Z, i, &y)); 693 if (!(osm->type & PC_GASM_RESTRICT)) { 694 /* have to zero the work RHS since scatter may leave some slots empty */ 695 PetscCall(VecZeroEntries(y)); 696 PetscCall(VecScatterBegin(osm->girestriction, x, y, INSERT_VALUES, forward)); 697 PetscCall(VecScatterEnd(osm->girestriction, x, y, INSERT_VALUES, forward)); 698 } else { 699 PetscCall(VecScatterBegin(osm->gorestriction, x, y, INSERT_VALUES, forward)); 700 PetscCall(VecScatterEnd(osm->gorestriction, x, y, INSERT_VALUES, forward)); 701 } 702 PetscCall(MatDenseRestoreColumnVecWrite(Z, i, &y)); 703 PetscCall(MatDenseRestoreColumnVecRead(X, i, &x)); 704 } 705 PetscCall(MatCreateDense(PetscObjectComm((PetscObject)osm->ois[0]), m, PETSC_DECIDE, M, N, NULL, &W)); 706 PetscCall(MatSetOption(Z, MAT_NO_OFF_PROC_ENTRIES, PETSC_TRUE)); 707 PetscCall(MatAssemblyBegin(Z, MAT_FINAL_ASSEMBLY)); 708 PetscCall(MatAssemblyEnd(Z, MAT_FINAL_ASSEMBLY)); 709 /* do the subdomain solve */ 710 PetscCall(KSPMatSolve(osm->ksp[0], Z, W)); 711 PetscCall(KSPCheckSolve(osm->ksp[0], pc, NULL)); 712 PetscCall(MatDestroy(&Z)); 713 /* do we need to zero y? */ 714 PetscCall(MatZeroEntries(Y)); 715 for (i = 0; i < N; ++i) { 716 PetscCall(MatDenseGetColumnVecWrite(Y, i, &y)); 717 PetscCall(MatDenseGetColumnVecRead(W, i, &x)); 718 if (!(osm->type & PC_GASM_INTERPOLATE)) { 719 PetscCall(VecScatterBegin(osm->girestriction, x, y, ADD_VALUES, reverse)); 720 PetscCall(VecScatterEnd(osm->girestriction, x, y, ADD_VALUES, reverse)); 721 } else { 722 PetscCall(VecScatterBegin(osm->gorestriction, x, y, ADD_VALUES, reverse)); 723 PetscCall(VecScatterEnd(osm->gorestriction, x, y, ADD_VALUES, reverse)); 724 } 725 PetscCall(MatDenseRestoreColumnVecRead(W, i, &x)); 726 if (osm->pctoouter) { 727 PetscCall(MatDenseGetColumnVecWrite(Yout, i, &x)); 728 PetscCall(VecScatterBegin(osm->pctoouter, y, x, INSERT_VALUES, SCATTER_FORWARD)); 729 PetscCall(VecScatterEnd(osm->pctoouter, y, x, INSERT_VALUES, SCATTER_FORWARD)); 730 PetscCall(MatDenseRestoreColumnVecRead(Yout, i, &x)); 731 } 732 PetscCall(MatDenseRestoreColumnVecWrite(Y, i, &y)); 733 } 734 PetscCall(MatDestroy(&W)); 735 PetscCall(MatDestroy(&O)); 736 PetscFunctionReturn(PETSC_SUCCESS); 737 } 738 739 static PetscErrorCode PCApplyTranspose_GASM(PC pc, Vec xin, Vec yout) 740 { 741 PC_GASM *osm = (PC_GASM *)pc->data; 742 PetscInt i; 743 Vec x, y; 744 ScatterMode forward = SCATTER_FORWARD, reverse = SCATTER_REVERSE; 745 746 PetscFunctionBegin; 747 if (osm->pctoouter) { 748 PetscCall(VecScatterBegin(osm->pctoouter, xin, osm->pcx, INSERT_VALUES, SCATTER_REVERSE)); 749 PetscCall(VecScatterEnd(osm->pctoouter, xin, osm->pcx, INSERT_VALUES, SCATTER_REVERSE)); 750 x = osm->pcx; 751 y = osm->pcy; 752 } else { 753 x = xin; 754 y = yout; 755 } 756 /* 757 Support for limiting the restriction or interpolation to only local 758 subdomain values (leaving the other values 0). 759 760 Note: these are reversed from the PCApply_GASM() because we are applying the 761 transpose of the three terms 762 */ 763 if (!(osm->type & PC_GASM_INTERPOLATE)) { 764 /* have to zero the work RHS since scatter may leave some slots empty */ 765 PetscCall(VecZeroEntries(osm->gx)); 766 PetscCall(VecScatterBegin(osm->girestriction, x, osm->gx, INSERT_VALUES, forward)); 767 } else { 768 PetscCall(VecScatterBegin(osm->gorestriction, x, osm->gx, INSERT_VALUES, forward)); 769 } 770 PetscCall(VecZeroEntries(osm->gy)); 771 if (!(osm->type & PC_GASM_INTERPOLATE)) { 772 PetscCall(VecScatterEnd(osm->girestriction, x, osm->gx, INSERT_VALUES, forward)); 773 } else { 774 PetscCall(VecScatterEnd(osm->gorestriction, x, osm->gx, INSERT_VALUES, forward)); 775 } 776 /* do the local solves */ 777 for (i = 0; i < osm->n; ++i) { /* Note that the solves are local, so we can go to osm->n, rather than osm->nmax. */ 778 PetscCall(KSPSolveTranspose(osm->ksp[i], osm->x[i], osm->y[i])); 779 PetscCall(KSPCheckSolve(osm->ksp[i], pc, osm->y[i])); 780 } 781 PetscCall(VecZeroEntries(y)); 782 if (!(osm->type & PC_GASM_RESTRICT)) { 783 PetscCall(VecScatterBegin(osm->girestriction, osm->gy, y, ADD_VALUES, reverse)); 784 PetscCall(VecScatterEnd(osm->girestriction, osm->gy, y, ADD_VALUES, reverse)); 785 } else { 786 PetscCall(VecScatterBegin(osm->gorestriction, osm->gy, y, ADD_VALUES, reverse)); 787 PetscCall(VecScatterEnd(osm->gorestriction, osm->gy, y, ADD_VALUES, reverse)); 788 } 789 if (osm->pctoouter) { 790 PetscCall(VecScatterBegin(osm->pctoouter, y, yout, INSERT_VALUES, SCATTER_FORWARD)); 791 PetscCall(VecScatterEnd(osm->pctoouter, y, yout, INSERT_VALUES, SCATTER_FORWARD)); 792 } 793 PetscFunctionReturn(PETSC_SUCCESS); 794 } 795 796 static PetscErrorCode PCReset_GASM(PC pc) 797 { 798 PC_GASM *osm = (PC_GASM *)pc->data; 799 PetscInt i; 800 801 PetscFunctionBegin; 802 if (osm->ksp) { 803 for (i = 0; i < osm->n; i++) PetscCall(KSPReset(osm->ksp[i])); 804 } 805 if (osm->pmat) { 806 if (osm->n > 0) { 807 PetscMPIInt size; 808 PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)pc), &size)); 809 if (size > 1) { 810 /* osm->pmat is created by MatCreateSubMatricesMPI(), cannot use MatDestroySubMatrices() */ 811 PetscCall(MatDestroyMatrices(osm->n, &osm->pmat)); 812 } else { 813 PetscCall(MatDestroySubMatrices(osm->n, &osm->pmat)); 814 } 815 } 816 } 817 if (osm->x) { 818 for (i = 0; i < osm->n; i++) { 819 PetscCall(VecDestroy(&osm->x[i])); 820 PetscCall(VecDestroy(&osm->y[i])); 821 } 822 } 823 PetscCall(VecDestroy(&osm->gx)); 824 PetscCall(VecDestroy(&osm->gy)); 825 826 PetscCall(VecScatterDestroy(&osm->gorestriction)); 827 PetscCall(VecScatterDestroy(&osm->girestriction)); 828 if (!osm->user_subdomains) { 829 PetscCall(PCGASMDestroySubdomains(osm->n, &osm->ois, &osm->iis)); 830 osm->N = PETSC_DETERMINE; 831 osm->nmax = PETSC_DETERMINE; 832 } 833 if (osm->pctoouter) PetscCall(VecScatterDestroy(&osm->pctoouter)); 834 if (osm->permutationIS) PetscCall(ISDestroy(&osm->permutationIS)); 835 if (osm->pcx) PetscCall(VecDestroy(&osm->pcx)); 836 if (osm->pcy) PetscCall(VecDestroy(&osm->pcy)); 837 if (osm->permutationP) PetscCall(MatDestroy(&osm->permutationP)); 838 if (osm->pcmat) PetscCall(MatDestroy(&osm->pcmat)); 839 PetscFunctionReturn(PETSC_SUCCESS); 840 } 841 842 static PetscErrorCode PCDestroy_GASM(PC pc) 843 { 844 PC_GASM *osm = (PC_GASM *)pc->data; 845 PetscInt i; 846 847 PetscFunctionBegin; 848 PetscCall(PCReset_GASM(pc)); 849 /* PCReset will not destroy subdomains, if user_subdomains is true. */ 850 PetscCall(PCGASMDestroySubdomains(osm->n, &osm->ois, &osm->iis)); 851 if (osm->ksp) { 852 for (i = 0; i < osm->n; i++) PetscCall(KSPDestroy(&osm->ksp[i])); 853 PetscCall(PetscFree(osm->ksp)); 854 } 855 PetscCall(PetscFree(osm->x)); 856 PetscCall(PetscFree(osm->y)); 857 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCGASMSetSubdomains_C", NULL)); 858 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCGASMSetOverlap_C", NULL)); 859 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCGASMSetType_C", NULL)); 860 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCGASMSetSortIndices_C", NULL)); 861 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCGASMGetSubKSP_C", NULL)); 862 PetscCall(PetscFree(pc->data)); 863 PetscFunctionReturn(PETSC_SUCCESS); 864 } 865 866 static PetscErrorCode PCSetFromOptions_GASM(PC pc, PetscOptionItems PetscOptionsObject) 867 { 868 PC_GASM *osm = (PC_GASM *)pc->data; 869 PetscInt blocks, ovl; 870 PetscBool flg; 871 PCGASMType gasmtype; 872 873 PetscFunctionBegin; 874 PetscOptionsHeadBegin(PetscOptionsObject, "Generalized additive Schwarz options"); 875 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)); 876 PetscCall(PetscOptionsInt("-pc_gasm_total_subdomains", "Total number of subdomains across communicator", "PCGASMSetTotalSubdomains", osm->N, &blocks, &flg)); 877 if (flg) PetscCall(PCGASMSetTotalSubdomains(pc, blocks)); 878 PetscCall(PetscOptionsInt("-pc_gasm_overlap", "Number of overlapping degrees of freedom", "PCGASMSetOverlap", osm->overlap, &ovl, &flg)); 879 if (flg) { 880 PetscCall(PCGASMSetOverlap(pc, ovl)); 881 osm->dm_subdomains = PETSC_FALSE; 882 } 883 flg = PETSC_FALSE; 884 PetscCall(PetscOptionsEnum("-pc_gasm_type", "Type of restriction/extension", "PCGASMSetType", PCGASMTypes, (PetscEnum)osm->type, (PetscEnum *)&gasmtype, &flg)); 885 if (flg) PetscCall(PCGASMSetType(pc, gasmtype)); 886 PetscCall(PetscOptionsBool("-pc_gasm_use_hierachical_partitioning", "use hierarchical partitioning", NULL, osm->hierarchicalpartitioning, &osm->hierarchicalpartitioning, &flg)); 887 PetscOptionsHeadEnd(); 888 PetscFunctionReturn(PETSC_SUCCESS); 889 } 890 891 /*@ 892 PCGASMSetTotalSubdomains - sets the total number of subdomains to use across the communicator for `PCGASM` 893 894 Logically Collective 895 896 Input Parameters: 897 + pc - the preconditioner 898 - N - total number of subdomains 899 900 Level: beginner 901 902 .seealso: [](ch_ksp), `PCGASM`, `PCGASMSetSubdomains()`, `PCGASMSetOverlap()` 903 `PCGASMCreateSubdomains2D()` 904 @*/ 905 PetscErrorCode PCGASMSetTotalSubdomains(PC pc, PetscInt N) 906 { 907 PC_GASM *osm = (PC_GASM *)pc->data; 908 PetscMPIInt size, rank; 909 910 PetscFunctionBegin; 911 PetscCheck(N >= 1, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Total number of subdomains must be 1 or more, got N = %" PetscInt_FMT, N); 912 PetscCheck(!pc->setupcalled, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONGSTATE, "PCGASMSetTotalSubdomains() should be called before calling PCSetUp()."); 913 914 PetscCall(PCGASMDestroySubdomains(osm->n, &osm->iis, &osm->ois)); 915 osm->ois = osm->iis = NULL; 916 917 PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)pc), &size)); 918 PetscCallMPI(MPI_Comm_rank(PetscObjectComm((PetscObject)pc), &rank)); 919 osm->N = N; 920 osm->n = PETSC_DETERMINE; 921 osm->nmax = PETSC_DETERMINE; 922 osm->dm_subdomains = PETSC_FALSE; 923 PetscFunctionReturn(PETSC_SUCCESS); 924 } 925 926 static PetscErrorCode PCGASMSetSubdomains_GASM(PC pc, PetscInt n, IS iis[], IS ois[]) 927 { 928 PC_GASM *osm = (PC_GASM *)pc->data; 929 PetscInt i; 930 931 PetscFunctionBegin; 932 PetscCheck(n >= 1, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Each MPI rank must have 1 or more subdomains, got n = %" PetscInt_FMT, n); 933 PetscCheck(!pc->setupcalled, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONGSTATE, "PCGASMSetSubdomains() should be called before calling PCSetUp()."); 934 935 PetscCall(PCGASMDestroySubdomains(osm->n, &osm->iis, &osm->ois)); 936 osm->iis = osm->ois = NULL; 937 osm->n = n; 938 osm->N = PETSC_DETERMINE; 939 osm->nmax = PETSC_DETERMINE; 940 if (ois) { 941 PetscCall(PetscMalloc1(n, &osm->ois)); 942 for (i = 0; i < n; i++) { 943 PetscCall(PetscObjectReference((PetscObject)ois[i])); 944 osm->ois[i] = ois[i]; 945 } 946 /* 947 Since the user set the outer subdomains, even if nontrivial overlap was requested via PCGASMSetOverlap(), 948 it will be ignored. To avoid confusion later on (e.g., when viewing the PC), the overlap size is set to -1. 949 */ 950 osm->overlap = -1; 951 /* inner subdomains must be provided */ 952 PetscCheck(iis, PETSC_COMM_SELF, PETSC_ERR_ARG_NULL, "inner indices have to be provided "); 953 } /* end if */ 954 if (iis) { 955 PetscCall(PetscMalloc1(n, &osm->iis)); 956 for (i = 0; i < n; i++) { 957 PetscCall(PetscObjectReference((PetscObject)iis[i])); 958 osm->iis[i] = iis[i]; 959 } 960 if (!ois) { 961 osm->ois = NULL; 962 /* if user does not provide outer indices, we will create the corresponding outer indices using osm->overlap =1 in PCSetUp_GASM */ 963 } 964 } 965 if (PetscDefined(USE_DEBUG)) { 966 PetscInt j, rstart, rend, *covered, lsize; 967 const PetscInt *indices; 968 /* check if the inner indices cover and only cover the local portion of the preconditioning matrix */ 969 PetscCall(MatGetOwnershipRange(pc->pmat, &rstart, &rend)); 970 PetscCall(PetscCalloc1(rend - rstart, &covered)); 971 /* check if the current MPI process owns indices from others */ 972 for (i = 0; i < n; i++) { 973 PetscCall(ISGetIndices(osm->iis[i], &indices)); 974 PetscCall(ISGetLocalSize(osm->iis[i], &lsize)); 975 for (j = 0; j < lsize; j++) { 976 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]); 977 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]); 978 covered[indices[j] - rstart] = 1; 979 } 980 PetscCall(ISRestoreIndices(osm->iis[i], &indices)); 981 } 982 /* check if we miss any indices */ 983 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); 984 PetscCall(PetscFree(covered)); 985 } 986 if (iis) osm->user_subdomains = PETSC_TRUE; 987 PetscFunctionReturn(PETSC_SUCCESS); 988 } 989 990 static PetscErrorCode PCGASMSetOverlap_GASM(PC pc, PetscInt ovl) 991 { 992 PC_GASM *osm = (PC_GASM *)pc->data; 993 994 PetscFunctionBegin; 995 PetscCheck(ovl >= 0, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_OUTOFRANGE, "Negative overlap value requested"); 996 PetscCheck(!pc->setupcalled || ovl == osm->overlap, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONGSTATE, "PCGASMSetOverlap() should be called before PCSetUp()."); 997 if (!pc->setupcalled) osm->overlap = ovl; 998 PetscFunctionReturn(PETSC_SUCCESS); 999 } 1000 1001 static PetscErrorCode PCGASMSetType_GASM(PC pc, PCGASMType type) 1002 { 1003 PC_GASM *osm = (PC_GASM *)pc->data; 1004 1005 PetscFunctionBegin; 1006 osm->type = type; 1007 osm->type_set = PETSC_TRUE; 1008 PetscFunctionReturn(PETSC_SUCCESS); 1009 } 1010 1011 static PetscErrorCode PCGASMSetSortIndices_GASM(PC pc, PetscBool doSort) 1012 { 1013 PC_GASM *osm = (PC_GASM *)pc->data; 1014 1015 PetscFunctionBegin; 1016 osm->sort_indices = doSort; 1017 PetscFunctionReturn(PETSC_SUCCESS); 1018 } 1019 1020 /* 1021 FIXME: This routine might need to be modified now that multiple processes per subdomain are allowed. 1022 In particular, it would upset the global subdomain number calculation. 1023 */ 1024 static PetscErrorCode PCGASMGetSubKSP_GASM(PC pc, PetscInt *n, PetscInt *first, KSP **ksp) 1025 { 1026 PC_GASM *osm = (PC_GASM *)pc->data; 1027 1028 PetscFunctionBegin; 1029 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"); 1030 1031 if (n) *n = osm->n; 1032 if (first) { 1033 PetscCallMPI(MPI_Scan(&osm->n, first, 1, MPIU_INT, MPI_SUM, PetscObjectComm((PetscObject)pc))); 1034 *first -= osm->n; 1035 } 1036 if (ksp) { 1037 /* Assume that local solves are now different; not necessarily 1038 true, though! This flag is used only for PCView_GASM() */ 1039 *ksp = osm->ksp; 1040 osm->same_subdomain_solvers = PETSC_FALSE; 1041 } 1042 PetscFunctionReturn(PETSC_SUCCESS); 1043 } /* PCGASMGetSubKSP_GASM() */ 1044 1045 /*@ 1046 PCGASMSetSubdomains - Sets the subdomains for this MPI process 1047 for the additive Schwarz preconditioner with multiple MPI processes per subdomain, `PCGASM` 1048 1049 Collective 1050 1051 Input Parameters: 1052 + pc - the preconditioner object 1053 . n - the number of subdomains for this MPI process 1054 . iis - the index sets that define the inner subdomains (or `NULL` for PETSc to determine subdomains), the `iis` array is 1055 copied so may be freed after this call. 1056 - ois - the index sets that define the outer subdomains (or `NULL` to use the same as `iis`, or to construct by expanding `iis` by 1057 the requested overlap), the `ois` array is copied so may be freed after this call. 1058 1059 Level: advanced 1060 1061 Notes: 1062 The `IS` indices use the parallel, global numbering of the vector entries. 1063 1064 Inner subdomains are those where the correction is applied. 1065 1066 Outer subdomains are those where the residual necessary to obtain the 1067 corrections is obtained (see `PCGASMType` for the use of inner/outer subdomains). 1068 1069 Both inner and outer subdomains can extend over several MPI processes. 1070 This process' portion of a subdomain is known as a local subdomain. 1071 1072 Inner subdomains can not overlap with each other, do not have any entities from remote processes, 1073 and have to cover the entire local subdomain owned by the current process. The index sets on each 1074 process should be ordered such that the ith local subdomain is connected to the ith remote subdomain 1075 on another MPI process. 1076 1077 By default the `PGASM` preconditioner uses 1 (local) subdomain per MPI process. 1078 1079 The `iis` and `ois` arrays may be freed after this call using `PCGASMDestroySubdomains()` 1080 1081 .seealso: [](ch_ksp), `PCGASM`, `PCGASMSetOverlap()`, `PCGASMGetSubKSP()`, `PCGASMDestroySubdomains()`, 1082 `PCGASMCreateSubdomains2D()`, `PCGASMGetSubdomains()` 1083 @*/ 1084 PetscErrorCode PCGASMSetSubdomains(PC pc, PetscInt n, IS iis[], IS ois[]) 1085 { 1086 PC_GASM *osm = (PC_GASM *)pc->data; 1087 1088 PetscFunctionBegin; 1089 PetscValidHeaderSpecific(pc, PC_CLASSID, 1); 1090 PetscTryMethod(pc, "PCGASMSetSubdomains_C", (PC, PetscInt, IS[], IS[]), (pc, n, iis, ois)); 1091 osm->dm_subdomains = PETSC_FALSE; 1092 PetscFunctionReturn(PETSC_SUCCESS); 1093 } 1094 1095 /*@ 1096 PCGASMSetOverlap - Sets the overlap between a pair of subdomains for the 1097 additive Schwarz preconditioner `PCGASM`. Either all or no MPI processes in the 1098 pc communicator must call this routine. 1099 1100 Logically Collective 1101 1102 Input Parameters: 1103 + pc - the preconditioner context 1104 - ovl - the amount of overlap between subdomains (ovl >= 0, default value = 0) 1105 1106 Options Database Key: 1107 . -pc_gasm_overlap <overlap> - Sets overlap 1108 1109 Level: intermediate 1110 1111 Notes: 1112 By default the `PCGASM` preconditioner uses 1 subdomain per process. To use 1113 multiple subdomain per perocessor or "straddling" subdomains that intersect 1114 multiple processes use `PCGASMSetSubdomains()` (or option `-pc_gasm_total_subdomains` <n>). 1115 1116 The overlap defaults to 0, so if one desires that no additional 1117 overlap be computed beyond what may have been set with a call to 1118 `PCGASMSetSubdomains()`, then `ovl` must be set to be 0. In particular, if one does 1119 not explicitly set the subdomains in application code, then all overlap would be computed 1120 internally by PETSc, and using an overlap of 0 would result in an `PCGASM` 1121 variant that is equivalent to the block Jacobi preconditioner. 1122 1123 One can define initial index sets with any overlap via 1124 `PCGASMSetSubdomains()`; the routine `PCGASMSetOverlap()` merely allows 1125 PETSc to extend that overlap further, if desired. 1126 1127 .seealso: [](ch_ksp), `PCGASM`, `PCGASMSetSubdomains()`, `PCGASMGetSubKSP()`, 1128 `PCGASMCreateSubdomains2D()`, `PCGASMGetSubdomains()` 1129 @*/ 1130 PetscErrorCode PCGASMSetOverlap(PC pc, PetscInt ovl) 1131 { 1132 PC_GASM *osm = (PC_GASM *)pc->data; 1133 1134 PetscFunctionBegin; 1135 PetscValidHeaderSpecific(pc, PC_CLASSID, 1); 1136 PetscValidLogicalCollectiveInt(pc, ovl, 2); 1137 PetscTryMethod(pc, "PCGASMSetOverlap_C", (PC, PetscInt), (pc, ovl)); 1138 osm->dm_subdomains = PETSC_FALSE; 1139 PetscFunctionReturn(PETSC_SUCCESS); 1140 } 1141 1142 /*@ 1143 PCGASMSetType - Sets the type of restriction and interpolation used 1144 for local problems in the `PCGASM` additive Schwarz method. 1145 1146 Logically Collective 1147 1148 Input Parameters: 1149 + pc - the preconditioner context 1150 - type - variant of `PCGASM`, one of 1151 .vb 1152 `PC_GASM_BASIC` - full interpolation and restriction 1153 `PC_GASM_RESTRICT` - full restriction, local MPI process interpolation 1154 `PC_GASM_INTERPOLATE` - full interpolation, local MPI process restriction 1155 `PC_GASM_NONE` - local MPI process restriction and interpolation 1156 .ve 1157 1158 Options Database Key: 1159 . -pc_gasm_type [basic,restrict,interpolate,none] - Sets `PCGASM` type 1160 1161 Level: intermediate 1162 1163 .seealso: [](ch_ksp), `PCGASM`, `PCGASMSetSubdomains()`, `PCGASMGetSubKSP()`, 1164 `PCGASMCreateSubdomains2D()`, `PCASM`, `PCASMSetType()` 1165 @*/ 1166 PetscErrorCode PCGASMSetType(PC pc, PCGASMType type) 1167 { 1168 PetscFunctionBegin; 1169 PetscValidHeaderSpecific(pc, PC_CLASSID, 1); 1170 PetscValidLogicalCollectiveEnum(pc, type, 2); 1171 PetscTryMethod(pc, "PCGASMSetType_C", (PC, PCGASMType), (pc, type)); 1172 PetscFunctionReturn(PETSC_SUCCESS); 1173 } 1174 1175 /*@ 1176 PCGASMSetSortIndices - Determines whether subdomain indices are sorted. 1177 1178 Logically Collective 1179 1180 Input Parameters: 1181 + pc - the preconditioner context 1182 - doSort - sort the subdomain indices 1183 1184 Level: intermediate 1185 1186 .seealso: [](ch_ksp), `PCGASM`, `PCGASMSetSubdomains()`, `PCGASMGetSubKSP()`, 1187 `PCGASMCreateSubdomains2D()` 1188 @*/ 1189 PetscErrorCode PCGASMSetSortIndices(PC pc, PetscBool doSort) 1190 { 1191 PetscFunctionBegin; 1192 PetscValidHeaderSpecific(pc, PC_CLASSID, 1); 1193 PetscValidLogicalCollectiveBool(pc, doSort, 2); 1194 PetscTryMethod(pc, "PCGASMSetSortIndices_C", (PC, PetscBool), (pc, doSort)); 1195 PetscFunctionReturn(PETSC_SUCCESS); 1196 } 1197 1198 /*@C 1199 PCGASMGetSubKSP - Gets the local `KSP` contexts for all subdomains on this MPI process. 1200 1201 Collective iff first_local is requested 1202 1203 Input Parameter: 1204 . pc - the preconditioner context 1205 1206 Output Parameters: 1207 + n_local - the number of blocks on this MPI process or `NULL` 1208 . first_local - the global number of the first block on this process or `NULL`, all processes must request or all must pass `NULL` 1209 - ksp - the array of `KSP` contexts 1210 1211 Level: advanced 1212 1213 Note: 1214 After `PCGASMGetSubKSP()` the array of `KSP`es is not to be freed 1215 1216 Currently for some matrix implementations only 1 block per MPI process 1217 is supported. 1218 1219 You must call `KSPSetUp()` before calling `PCGASMGetSubKSP()`. 1220 1221 .seealso: [](ch_ksp), `PCGASM`, `PCGASMSetSubdomains()`, `PCGASMSetOverlap()`, 1222 `PCGASMCreateSubdomains2D()`, 1223 @*/ 1224 PetscErrorCode PCGASMGetSubKSP(PC pc, PetscInt *n_local, PetscInt *first_local, KSP *ksp[]) 1225 { 1226 PetscFunctionBegin; 1227 PetscValidHeaderSpecific(pc, PC_CLASSID, 1); 1228 PetscUseMethod(pc, "PCGASMGetSubKSP_C", (PC, PetscInt *, PetscInt *, KSP **), (pc, n_local, first_local, ksp)); 1229 PetscFunctionReturn(PETSC_SUCCESS); 1230 } 1231 1232 /*MC 1233 PCGASM - Use the (restricted) additive Schwarz method, each block is (approximately) solved with 1234 its own `KSP` object on a subset of MPI processes 1235 1236 Options Database Keys: 1237 + -pc_gasm_total_subdomains <n> - Sets total number of local subdomains to be distributed among the MPI processes 1238 . -pc_gasm_view_subdomains - activates the printing of subdomain indices in `PCView()`, -ksp_view or -snes_view 1239 . -pc_gasm_print_subdomains - activates the printing of subdomain indices in `PCSetUp()` 1240 . -pc_gasm_overlap <ovl> - Sets overlap by which to (automatically) extend local subdomains 1241 - -pc_gasm_type [basic,restrict,interpolate,none] - Sets `PCGASMType` 1242 1243 Level: beginner 1244 1245 Notes: 1246 To set options on the solvers for each block append `-sub_` to all the `KSP`, and `PC` 1247 options database keys. For example, `-sub_pc_type ilu -sub_pc_factor_levels 1 -sub_ksp_type preonly` 1248 1249 To set the options on the solvers separate for each block call `PCGASMGetSubKSP()` 1250 and set the options directly on the resulting `KSP` object (you can access its `PC` 1251 with `KSPGetPC()`) 1252 1253 See {cite}`dryja1987additive` and {cite}`1sbg` for details on additive Schwarz algorithms 1254 1255 .seealso: [](ch_ksp), `PCCreate()`, `PCSetType()`, `PCType`, `PC`, `PCASM`, `PCGASMType`, `PCGASMSetType()`, 1256 `PCBJACOBI`, `PCGASMGetSubKSP()`, `PCGASMSetSubdomains()`, 1257 `PCSetModifySubMatrices()`, `PCGASMSetOverlap()`, `PCGASMSetType()` 1258 M*/ 1259 1260 PETSC_EXTERN PetscErrorCode PCCreate_GASM(PC pc) 1261 { 1262 PC_GASM *osm; 1263 1264 PetscFunctionBegin; 1265 PetscCall(PetscNew(&osm)); 1266 1267 osm->N = PETSC_DETERMINE; 1268 osm->n = PETSC_DECIDE; 1269 osm->nmax = PETSC_DETERMINE; 1270 osm->overlap = 0; 1271 osm->ksp = NULL; 1272 osm->gorestriction = NULL; 1273 osm->girestriction = NULL; 1274 osm->pctoouter = NULL; 1275 osm->gx = NULL; 1276 osm->gy = NULL; 1277 osm->x = NULL; 1278 osm->y = NULL; 1279 osm->pcx = NULL; 1280 osm->pcy = NULL; 1281 osm->permutationIS = NULL; 1282 osm->permutationP = NULL; 1283 osm->pcmat = NULL; 1284 osm->ois = NULL; 1285 osm->iis = NULL; 1286 osm->pmat = NULL; 1287 osm->type = PC_GASM_RESTRICT; 1288 osm->same_subdomain_solvers = PETSC_TRUE; 1289 osm->sort_indices = PETSC_TRUE; 1290 osm->dm_subdomains = PETSC_FALSE; 1291 osm->hierarchicalpartitioning = PETSC_FALSE; 1292 1293 pc->data = (void *)osm; 1294 pc->ops->apply = PCApply_GASM; 1295 pc->ops->matapply = PCMatApply_GASM; 1296 pc->ops->applytranspose = PCApplyTranspose_GASM; 1297 pc->ops->setup = PCSetUp_GASM; 1298 pc->ops->reset = PCReset_GASM; 1299 pc->ops->destroy = PCDestroy_GASM; 1300 pc->ops->setfromoptions = PCSetFromOptions_GASM; 1301 pc->ops->setuponblocks = PCSetUpOnBlocks_GASM; 1302 pc->ops->view = PCView_GASM; 1303 pc->ops->applyrichardson = NULL; 1304 1305 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCGASMSetSubdomains_C", PCGASMSetSubdomains_GASM)); 1306 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCGASMSetOverlap_C", PCGASMSetOverlap_GASM)); 1307 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCGASMSetType_C", PCGASMSetType_GASM)); 1308 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCGASMSetSortIndices_C", PCGASMSetSortIndices_GASM)); 1309 PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCGASMGetSubKSP_C", PCGASMGetSubKSP_GASM)); 1310 PetscFunctionReturn(PETSC_SUCCESS); 1311 } 1312 1313 PetscErrorCode PCGASMCreateLocalSubdomains(Mat A, PetscInt nloc, IS *iis[]) 1314 { 1315 MatPartitioning mpart; 1316 const char *prefix; 1317 PetscInt i, j, rstart, rend, bs; 1318 PetscBool hasop, isbaij = PETSC_FALSE, foundpart = PETSC_FALSE; 1319 Mat Ad = NULL, adj; 1320 IS ispart, isnumb, *is; 1321 1322 PetscFunctionBegin; 1323 PetscCheck(nloc >= 1, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "number of local subdomains must > 0, got nloc = %" PetscInt_FMT, nloc); 1324 1325 /* Get prefix, row distribution, and block size */ 1326 PetscCall(MatGetOptionsPrefix(A, &prefix)); 1327 PetscCall(MatGetOwnershipRange(A, &rstart, &rend)); 1328 PetscCall(MatGetBlockSize(A, &bs)); 1329 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); 1330 1331 /* Get diagonal block from matrix if possible */ 1332 PetscCall(MatHasOperation(A, MATOP_GET_DIAGONAL_BLOCK, &hasop)); 1333 if (hasop) PetscCall(MatGetDiagonalBlock(A, &Ad)); 1334 if (Ad) { 1335 PetscCall(PetscObjectBaseTypeCompare((PetscObject)Ad, MATSEQBAIJ, &isbaij)); 1336 if (!isbaij) PetscCall(PetscObjectBaseTypeCompare((PetscObject)Ad, MATSEQSBAIJ, &isbaij)); 1337 } 1338 if (Ad && nloc > 1) { 1339 PetscBool match, done; 1340 /* Try to setup a good matrix partitioning if available */ 1341 PetscCall(MatPartitioningCreate(PETSC_COMM_SELF, &mpart)); 1342 PetscCall(PetscObjectSetOptionsPrefix((PetscObject)mpart, prefix)); 1343 PetscCall(MatPartitioningSetFromOptions(mpart)); 1344 PetscCall(PetscObjectTypeCompare((PetscObject)mpart, MATPARTITIONINGCURRENT, &match)); 1345 if (!match) PetscCall(PetscObjectTypeCompare((PetscObject)mpart, MATPARTITIONINGSQUARE, &match)); 1346 if (!match) { /* assume a "good" partitioner is available */ 1347 PetscInt na; 1348 const PetscInt *ia, *ja; 1349 PetscCall(MatGetRowIJ(Ad, 0, PETSC_TRUE, isbaij, &na, &ia, &ja, &done)); 1350 if (done) { 1351 /* Build adjacency matrix by hand. Unfortunately a call to 1352 MatConvert(Ad,MATMPIADJ,MAT_INITIAL_MATRIX,&adj) will 1353 remove the block-aij structure and we cannot expect 1354 MatPartitioning to split vertices as we need */ 1355 PetscInt i, j, len, nnz, cnt, *iia = NULL, *jja = NULL; 1356 const PetscInt *row; 1357 nnz = 0; 1358 for (i = 0; i < na; i++) { /* count number of nonzeros */ 1359 len = ia[i + 1] - ia[i]; 1360 row = ja + ia[i]; 1361 for (j = 0; j < len; j++) { 1362 if (row[j] == i) { /* don't count diagonal */ 1363 len--; 1364 break; 1365 } 1366 } 1367 nnz += len; 1368 } 1369 PetscCall(PetscMalloc1(na + 1, &iia)); 1370 PetscCall(PetscMalloc1(nnz, &jja)); 1371 nnz = 0; 1372 iia[0] = 0; 1373 for (i = 0; i < na; i++) { /* fill adjacency */ 1374 cnt = 0; 1375 len = ia[i + 1] - ia[i]; 1376 row = ja + ia[i]; 1377 for (j = 0; j < len; j++) { 1378 if (row[j] != i) jja[nnz + cnt++] = row[j]; /* if not diagonal */ 1379 } 1380 nnz += cnt; 1381 iia[i + 1] = nnz; 1382 } 1383 /* Partitioning of the adjacency matrix */ 1384 PetscCall(MatCreateMPIAdj(PETSC_COMM_SELF, na, na, iia, jja, NULL, &adj)); 1385 PetscCall(MatPartitioningSetAdjacency(mpart, adj)); 1386 PetscCall(MatPartitioningSetNParts(mpart, nloc)); 1387 PetscCall(MatPartitioningApply(mpart, &ispart)); 1388 PetscCall(ISPartitioningToNumbering(ispart, &isnumb)); 1389 PetscCall(MatDestroy(&adj)); 1390 foundpart = PETSC_TRUE; 1391 } 1392 PetscCall(MatRestoreRowIJ(Ad, 0, PETSC_TRUE, isbaij, &na, &ia, &ja, &done)); 1393 } 1394 PetscCall(MatPartitioningDestroy(&mpart)); 1395 } 1396 PetscCall(PetscMalloc1(nloc, &is)); 1397 if (!foundpart) { 1398 /* Partitioning by contiguous chunks of rows */ 1399 1400 PetscInt mbs = (rend - rstart) / bs; 1401 PetscInt start = rstart; 1402 for (i = 0; i < nloc; i++) { 1403 PetscInt count = (mbs / nloc + ((mbs % nloc) > i)) * bs; 1404 PetscCall(ISCreateStride(PETSC_COMM_SELF, count, start, 1, &is[i])); 1405 start += count; 1406 } 1407 1408 } else { 1409 /* Partitioning by adjacency of diagonal block */ 1410 1411 const PetscInt *numbering; 1412 PetscInt *count, nidx, *indices, *newidx, start = 0; 1413 /* Get node count in each partition */ 1414 PetscCall(PetscMalloc1(nloc, &count)); 1415 PetscCall(ISPartitioningCount(ispart, nloc, count)); 1416 if (isbaij && bs > 1) { /* adjust for the block-aij case */ 1417 for (i = 0; i < nloc; i++) count[i] *= bs; 1418 } 1419 /* Build indices from node numbering */ 1420 PetscCall(ISGetLocalSize(isnumb, &nidx)); 1421 PetscCall(PetscMalloc1(nidx, &indices)); 1422 for (i = 0; i < nidx; i++) indices[i] = i; /* needs to be initialized */ 1423 PetscCall(ISGetIndices(isnumb, &numbering)); 1424 PetscCall(PetscSortIntWithPermutation(nidx, numbering, indices)); 1425 PetscCall(ISRestoreIndices(isnumb, &numbering)); 1426 if (isbaij && bs > 1) { /* adjust for the block-aij case */ 1427 PetscCall(PetscMalloc1(nidx * bs, &newidx)); 1428 for (i = 0; i < nidx; i++) { 1429 for (j = 0; j < bs; j++) newidx[i * bs + j] = indices[i] * bs + j; 1430 } 1431 PetscCall(PetscFree(indices)); 1432 nidx *= bs; 1433 indices = newidx; 1434 } 1435 /* Shift to get global indices */ 1436 for (i = 0; i < nidx; i++) indices[i] += rstart; 1437 1438 /* Build the index sets for each block */ 1439 for (i = 0; i < nloc; i++) { 1440 PetscCall(ISCreateGeneral(PETSC_COMM_SELF, count[i], &indices[start], PETSC_COPY_VALUES, &is[i])); 1441 PetscCall(ISSort(is[i])); 1442 start += count[i]; 1443 } 1444 1445 PetscCall(PetscFree(count)); 1446 PetscCall(PetscFree(indices)); 1447 PetscCall(ISDestroy(&isnumb)); 1448 PetscCall(ISDestroy(&ispart)); 1449 } 1450 *iis = is; 1451 PetscFunctionReturn(PETSC_SUCCESS); 1452 } 1453 1454 PETSC_INTERN PetscErrorCode PCGASMCreateStraddlingSubdomains(Mat A, PetscInt N, PetscInt *n, IS *iis[]) 1455 { 1456 PetscFunctionBegin; 1457 PetscCall(MatSubdomainsCreateCoalesce(A, N, n, iis)); 1458 PetscFunctionReturn(PETSC_SUCCESS); 1459 } 1460 1461 /*@C 1462 PCGASMCreateSubdomains - Creates `n` index sets defining `n` nonoverlapping subdomains on this MPI process for the `PCGASM` additive 1463 Schwarz preconditioner for a any problem based on its matrix. 1464 1465 Collective 1466 1467 Input Parameters: 1468 + A - The global matrix operator 1469 - N - the number of global subdomains requested 1470 1471 Output Parameters: 1472 + n - the number of subdomains created on this MPI process 1473 - iis - the array of index sets defining the local inner subdomains (on which the correction is applied) 1474 1475 Level: advanced 1476 1477 Notes: 1478 When `N` >= A's communicator size, each subdomain is local -- contained within a single MPI process. 1479 When `N` < size, the subdomains are 'straddling' (process boundaries) and are no longer local. 1480 The resulting subdomains can be use in `PCGASMSetSubdomains`(pc,n,iss,`NULL`). The overlapping 1481 outer subdomains will be automatically generated from these according to the requested amount of 1482 overlap; this is currently supported only with local subdomains. 1483 1484 Use `PCGASMDestroySubdomains()` to free the array and the list of index sets. 1485 1486 .seealso: [](ch_ksp), `PCGASM`, `PCGASMSetSubdomains()`, `PCGASMDestroySubdomains()` 1487 @*/ 1488 PetscErrorCode PCGASMCreateSubdomains(Mat A, PetscInt N, PetscInt *n, IS *iis[]) 1489 { 1490 PetscMPIInt size; 1491 1492 PetscFunctionBegin; 1493 PetscValidHeaderSpecific(A, MAT_CLASSID, 1); 1494 PetscAssertPointer(iis, 4); 1495 1496 PetscCheck(N >= 1, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Number of subdomains must be > 0, N = %" PetscInt_FMT, N); 1497 PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)A), &size)); 1498 if (N >= size) { 1499 *n = N / size + (N % size); 1500 PetscCall(PCGASMCreateLocalSubdomains(A, *n, iis)); 1501 } else { 1502 PetscCall(PCGASMCreateStraddlingSubdomains(A, N, n, iis)); 1503 } 1504 PetscFunctionReturn(PETSC_SUCCESS); 1505 } 1506 1507 /*@C 1508 PCGASMDestroySubdomains - Destroys the index sets created with 1509 `PCGASMCreateSubdomains()` or `PCGASMCreateSubdomains2D()`. Should be 1510 called after setting subdomains with `PCGASMSetSubdomains()`. 1511 1512 Collective 1513 1514 Input Parameters: 1515 + n - the number of index sets 1516 . iis - the array of inner subdomains 1517 - ois - the array of outer subdomains, can be `NULL` 1518 1519 Level: intermediate 1520 1521 Note: 1522 This is a convenience subroutine that walks each list, 1523 destroys each `IS` on the list, and then frees the list. At the end the 1524 list pointers are set to `NULL`. 1525 1526 .seealso: [](ch_ksp), `PCGASM`, `PCGASMCreateSubdomains()`, `PCGASMSetSubdomains()` 1527 @*/ 1528 PetscErrorCode PCGASMDestroySubdomains(PetscInt n, IS *iis[], IS *ois[]) 1529 { 1530 PetscInt i; 1531 1532 PetscFunctionBegin; 1533 if (n <= 0) PetscFunctionReturn(PETSC_SUCCESS); 1534 if (ois) { 1535 PetscAssertPointer(ois, 3); 1536 if (*ois) { 1537 PetscAssertPointer(*ois, 3); 1538 for (i = 0; i < n; i++) PetscCall(ISDestroy(&(*ois)[i])); 1539 PetscCall(PetscFree(*ois)); 1540 } 1541 } 1542 if (iis) { 1543 PetscAssertPointer(iis, 2); 1544 if (*iis) { 1545 PetscAssertPointer(*iis, 2); 1546 for (i = 0; i < n; i++) PetscCall(ISDestroy(&(*iis)[i])); 1547 PetscCall(PetscFree(*iis)); 1548 } 1549 } 1550 PetscFunctionReturn(PETSC_SUCCESS); 1551 } 1552 1553 #define PCGASMLocalSubdomainBounds2D(M, N, xleft, ylow, xright, yhigh, first, last, xleft_loc, ylow_loc, xright_loc, yhigh_loc, n) \ 1554 do { \ 1555 PetscInt first_row = first / M, last_row = last / M + 1; \ 1556 /* \ 1557 Compute ylow_loc and yhigh_loc so that (ylow_loc,xleft) and (yhigh_loc,xright) are the corners \ 1558 of the bounding box of the intersection of the subdomain with the local ownership range (local \ 1559 subdomain). \ 1560 Also compute xleft_loc and xright_loc as the lower and upper bounds on the first and last rows \ 1561 of the intersection. \ 1562 */ \ 1563 /* ylow_loc is the grid row containing the first element of the local sumbdomain */ \ 1564 *ylow_loc = PetscMax(first_row, ylow); \ 1565 /* xleft_loc is the offset of first element of the local subdomain within its grid row (might actually be outside the local subdomain) */ \ 1566 *xleft_loc = *ylow_loc == first_row ? PetscMax(first % M, xleft) : xleft; \ 1567 /* yhigh_loc is the grid row above the last local subdomain element */ \ 1568 *yhigh_loc = PetscMin(last_row, yhigh); \ 1569 /* xright is the offset of the end of the local subdomain within its grid row (might actually be outside the local subdomain) */ \ 1570 *xright_loc = *yhigh_loc == last_row ? PetscMin(xright, last % M) : xright; \ 1571 /* Now compute the size of the local subdomain n. */ \ 1572 *n = 0; \ 1573 if (*ylow_loc < *yhigh_loc) { \ 1574 PetscInt width = xright - xleft; \ 1575 *n += width * (*yhigh_loc - *ylow_loc - 1); \ 1576 *n += PetscMin(PetscMax(*xright_loc - xleft, 0), width); \ 1577 *n -= PetscMin(PetscMax(*xleft_loc - xleft, 0), width); \ 1578 } \ 1579 } while (0) 1580 1581 /*@C 1582 PCGASMCreateSubdomains2D - Creates the index sets for the `PCGASM` overlapping Schwarz 1583 preconditioner for a two-dimensional problem on a regular grid. 1584 1585 Collective 1586 1587 Input Parameters: 1588 + pc - the preconditioner context 1589 . M - the global number of grid points in the x direction 1590 . N - the global number of grid points in the y direction 1591 . Mdomains - the global number of subdomains in the x direction 1592 . Ndomains - the global number of subdomains in the y direction 1593 . dof - degrees of freedom per node 1594 - overlap - overlap in mesh lines 1595 1596 Output Parameters: 1597 + nsub - the number of local subdomains created 1598 . iis - array of index sets defining inner (nonoverlapping) subdomains 1599 - ois - array of index sets defining outer (overlapping, if overlap > 0) subdomains 1600 1601 Level: advanced 1602 1603 Note: 1604 Use `PCGASMDestroySubdomains()` to free the index sets and the arrays 1605 1606 .seealso: [](ch_ksp), `PCGASM`, `PCGASMSetSubdomains()`, `PCGASMGetSubKSP()`, `PCGASMSetOverlap()`, `PCASMCreateSubdomains2D()`, 1607 `PCGASMDestroySubdomains()` 1608 @*/ 1609 PetscErrorCode PCGASMCreateSubdomains2D(PC pc, PetscInt M, PetscInt N, PetscInt Mdomains, PetscInt Ndomains, PetscInt dof, PetscInt overlap, PetscInt *nsub, IS *iis[], IS *ois[]) 1610 { 1611 PetscMPIInt size, rank; 1612 PetscInt i, j; 1613 PetscInt maxheight, maxwidth; 1614 PetscInt xstart, xleft, xright, xleft_loc, xright_loc; 1615 PetscInt ystart, ylow, yhigh, ylow_loc, yhigh_loc; 1616 PetscInt x[2][2], y[2][2], n[2]; 1617 PetscInt first, last; 1618 PetscInt nidx, *idx; 1619 PetscInt ii, jj, s, q, d; 1620 PetscInt k, kk; 1621 PetscMPIInt color; 1622 MPI_Comm comm, subcomm; 1623 IS **xis = NULL, **is = ois, **is_local = iis; 1624 1625 PetscFunctionBegin; 1626 PetscCall(PetscObjectGetComm((PetscObject)pc, &comm)); 1627 PetscCallMPI(MPI_Comm_size(comm, &size)); 1628 PetscCallMPI(MPI_Comm_rank(comm, &rank)); 1629 PetscCall(MatGetOwnershipRange(pc->pmat, &first, &last)); 1630 PetscCheck((first % dof) == 0 && (last % dof) == 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, 1631 "Matrix row partitioning unsuitable for domain decomposition: local row range (%" PetscInt_FMT ",%" PetscInt_FMT ") " 1632 "does not respect the number of degrees of freedom per grid point %" PetscInt_FMT, 1633 first, last, dof); 1634 1635 /* Determine the number of domains with nonzero intersections with the local ownership range. */ 1636 s = 0; 1637 ystart = 0; 1638 for (j = 0; j < Ndomains; ++j) { 1639 maxheight = N / Ndomains + ((N % Ndomains) > j); /* Maximal height of subdomain */ 1640 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); 1641 /* Vertical domain limits with an overlap. */ 1642 ylow = PetscMax(ystart - overlap, 0); 1643 yhigh = PetscMin(ystart + maxheight + overlap, N); 1644 xstart = 0; 1645 for (i = 0; i < Mdomains; ++i) { 1646 maxwidth = M / Mdomains + ((M % Mdomains) > i); /* Maximal width of subdomain */ 1647 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); 1648 /* Horizontal domain limits with an overlap. */ 1649 xleft = PetscMax(xstart - overlap, 0); 1650 xright = PetscMin(xstart + maxwidth + overlap, M); 1651 /* 1652 Determine whether this subdomain intersects this rank's ownership range of pc->pmat. 1653 */ 1654 PCGASMLocalSubdomainBounds2D(M, N, xleft, ylow, xright, yhigh, first, last, (&xleft_loc), (&ylow_loc), (&xright_loc), (&yhigh_loc), (&nidx)); 1655 if (nidx) ++s; 1656 xstart += maxwidth; 1657 } /* for (i = 0; i < Mdomains; ++i) */ 1658 ystart += maxheight; 1659 } /* for (j = 0; j < Ndomains; ++j) */ 1660 1661 /* Now we can allocate the necessary number of ISs. */ 1662 *nsub = s; 1663 PetscCall(PetscMalloc1(*nsub, is)); 1664 PetscCall(PetscMalloc1(*nsub, is_local)); 1665 s = 0; 1666 ystart = 0; 1667 for (j = 0; j < Ndomains; ++j) { 1668 maxheight = N / Ndomains + ((N % Ndomains) > j); /* Maximal height of subdomain */ 1669 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); 1670 /* Vertical domain limits with an overlap. */ 1671 y[0][0] = PetscMax(ystart - overlap, 0); 1672 y[0][1] = PetscMin(ystart + maxheight + overlap, N); 1673 /* Vertical domain limits without an overlap. */ 1674 y[1][0] = ystart; 1675 y[1][1] = PetscMin(ystart + maxheight, N); 1676 xstart = 0; 1677 for (i = 0; i < Mdomains; ++i) { 1678 maxwidth = M / Mdomains + ((M % Mdomains) > i); /* Maximal width of subdomain */ 1679 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); 1680 /* Horizontal domain limits with an overlap. */ 1681 x[0][0] = PetscMax(xstart - overlap, 0); 1682 x[0][1] = PetscMin(xstart + maxwidth + overlap, M); 1683 /* Horizontal domain limits without an overlap. */ 1684 x[1][0] = xstart; 1685 x[1][1] = PetscMin(xstart + maxwidth, M); 1686 /* 1687 Determine whether this domain intersects this rank's ownership range of pc->pmat. 1688 Do this twice: first for the domains with overlaps, and once without. 1689 During the first pass create the subcommunicators, and use them on the second pass as well. 1690 */ 1691 for (q = 0; q < 2; ++q) { 1692 PetscBool split = PETSC_FALSE; 1693 /* 1694 domain limits, (xleft, xright) and (ylow, yheigh) are adjusted 1695 according to whether the domain with an overlap or without is considered. 1696 */ 1697 xleft = x[q][0]; 1698 xright = x[q][1]; 1699 ylow = y[q][0]; 1700 yhigh = y[q][1]; 1701 PCGASMLocalSubdomainBounds2D(M, N, xleft, ylow, xright, yhigh, first, last, (&xleft_loc), (&ylow_loc), (&xright_loc), (&yhigh_loc), (&nidx)); 1702 nidx *= dof; 1703 n[q] = nidx; 1704 /* 1705 Based on the counted number of indices in the local domain *with an overlap*, 1706 construct a subcommunicator of all the MPI ranks supporting this domain. 1707 Observe that a domain with an overlap might have nontrivial local support, 1708 while the domain without an overlap might not. Hence, the decision to participate 1709 in the subcommunicator must be based on the domain with an overlap. 1710 */ 1711 if (q == 0) { 1712 if (nidx) color = 1; 1713 else color = MPI_UNDEFINED; 1714 PetscCallMPI(MPI_Comm_split(comm, color, rank, &subcomm)); 1715 split = PETSC_TRUE; 1716 } 1717 /* 1718 Proceed only if the number of local indices *with an overlap* is nonzero. 1719 */ 1720 if (n[0]) { 1721 if (q == 0) xis = is; 1722 if (q == 1) { 1723 /* 1724 The IS for the no-overlap subdomain shares a communicator with the overlapping domain. 1725 Moreover, if the overlap is zero, the two ISs are identical. 1726 */ 1727 if (overlap == 0) { 1728 (*is_local)[s] = (*is)[s]; 1729 PetscCall(PetscObjectReference((PetscObject)(*is)[s])); 1730 continue; 1731 } else { 1732 xis = is_local; 1733 subcomm = ((PetscObject)(*is)[s])->comm; 1734 } 1735 } /* if (q == 1) */ 1736 idx = NULL; 1737 PetscCall(PetscMalloc1(nidx, &idx)); 1738 if (nidx) { 1739 k = 0; 1740 for (jj = ylow_loc; jj < yhigh_loc; ++jj) { 1741 PetscInt x0 = (jj == ylow_loc) ? xleft_loc : xleft; 1742 PetscInt x1 = (jj == yhigh_loc - 1) ? xright_loc : xright; 1743 kk = dof * (M * jj + x0); 1744 for (ii = x0; ii < x1; ++ii) { 1745 for (d = 0; d < dof; ++d) idx[k++] = kk++; 1746 } 1747 } 1748 } 1749 PetscCall(ISCreateGeneral(subcomm, nidx, idx, PETSC_OWN_POINTER, (*xis) + s)); 1750 if (split) PetscCallMPI(MPI_Comm_free(&subcomm)); 1751 } /* if (n[0]) */ 1752 } /* for (q = 0; q < 2; ++q) */ 1753 if (n[0]) ++s; 1754 xstart += maxwidth; 1755 } /* for (i = 0; i < Mdomains; ++i) */ 1756 ystart += maxheight; 1757 } /* for (j = 0; j < Ndomains; ++j) */ 1758 PetscFunctionReturn(PETSC_SUCCESS); 1759 } 1760 1761 /*@C 1762 PCGASMGetSubdomains - Gets the subdomains supported on this MPI process 1763 for the `PCGASM` additive Schwarz preconditioner. 1764 1765 Not Collective 1766 1767 Input Parameter: 1768 . pc - the preconditioner context 1769 1770 Output Parameters: 1771 + n - the number of subdomains for this MPI process (default value = 1) 1772 . iis - the index sets that define the inner subdomains (without overlap) supported on this process (can be `NULL`) 1773 - ois - the index sets that define the outer subdomains (with overlap) supported on this process (can be `NULL`) 1774 1775 Level: advanced 1776 1777 Notes: 1778 The user is responsible for destroying the `IS`s and freeing the returned arrays, this can be done with 1779 `PCGASMDestroySubdomains()` 1780 1781 The `IS` numbering is in the parallel, global numbering of the vector. 1782 1783 .seealso: [](ch_ksp), `PCGASM`, `PCGASMSetOverlap()`, `PCGASMGetSubKSP()`, `PCGASMCreateSubdomains2D()`, 1784 `PCGASMSetSubdomains()`, `PCGASMGetSubmatrices()`, `PCGASMDestroySubdomains()` 1785 @*/ 1786 PetscErrorCode PCGASMGetSubdomains(PC pc, PetscInt *n, IS *iis[], IS *ois[]) 1787 { 1788 PC_GASM *osm; 1789 PetscBool match; 1790 PetscInt i; 1791 1792 PetscFunctionBegin; 1793 PetscValidHeaderSpecific(pc, PC_CLASSID, 1); 1794 PetscCall(PetscObjectTypeCompare((PetscObject)pc, PCGASM, &match)); 1795 PetscCheck(match, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONG, "Incorrect object type: expected %s, got %s instead", PCGASM, ((PetscObject)pc)->type_name); 1796 osm = (PC_GASM *)pc->data; 1797 if (n) *n = osm->n; 1798 if (iis) PetscCall(PetscMalloc1(osm->n, iis)); 1799 if (ois) PetscCall(PetscMalloc1(osm->n, ois)); 1800 if (iis || ois) { 1801 for (i = 0; i < osm->n; ++i) { 1802 if (iis) (*iis)[i] = osm->iis[i]; 1803 if (ois) (*ois)[i] = osm->ois[i]; 1804 } 1805 } 1806 PetscFunctionReturn(PETSC_SUCCESS); 1807 } 1808 1809 /*@C 1810 PCGASMGetSubmatrices - Gets the local submatrices (for this MPI process 1811 only) for the `PCGASM` additive Schwarz preconditioner. 1812 1813 Not Collective 1814 1815 Input Parameter: 1816 . pc - the preconditioner context 1817 1818 Output Parameters: 1819 + n - the number of matrices for this MPI process (default value = 1) 1820 - mat - the matrices 1821 1822 Level: advanced 1823 1824 Note: 1825 Matrices returned by this routine have the same communicators as the index sets (`IS`) 1826 used to define subdomains in `PCGASMSetSubdomains()` 1827 1828 .seealso: [](ch_ksp), `PCGASM`, `PCGASMSetOverlap()`, `PCGASMGetSubKSP()`, 1829 `PCGASMCreateSubdomains2D()`, `PCGASMSetSubdomains()`, `PCGASMGetSubdomains()` 1830 @*/ 1831 PetscErrorCode PCGASMGetSubmatrices(PC pc, PetscInt *n, Mat *mat[]) 1832 { 1833 PC_GASM *osm; 1834 PetscBool match; 1835 1836 PetscFunctionBegin; 1837 PetscValidHeaderSpecific(pc, PC_CLASSID, 1); 1838 PetscAssertPointer(n, 2); 1839 if (mat) PetscAssertPointer(mat, 3); 1840 PetscCheck(pc->setupcalled, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONGSTATE, "Must call after KSPSetUp() or PCSetUp()."); 1841 PetscCall(PetscObjectTypeCompare((PetscObject)pc, PCGASM, &match)); 1842 PetscCheck(match, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONG, "Expected %s, got %s instead", PCGASM, ((PetscObject)pc)->type_name); 1843 osm = (PC_GASM *)pc->data; 1844 if (n) *n = osm->n; 1845 if (mat) *mat = osm->pmat; 1846 PetscFunctionReturn(PETSC_SUCCESS); 1847 } 1848 1849 /*@ 1850 PCGASMSetUseDMSubdomains - Indicates whether to use `DMCreateDomainDecomposition()` to define the subdomains, whenever possible for `PCGASM` 1851 1852 Logically Collective 1853 1854 Input Parameters: 1855 + pc - the preconditioner 1856 - flg - boolean indicating whether to use subdomains defined by the `DM` 1857 1858 Options Database Key: 1859 + -pc_gasm_dm_subdomains - configure subdomains 1860 . -pc_gasm_overlap - set overlap 1861 - -pc_gasm_total_subdomains - set number of subdomains 1862 1863 Level: intermediate 1864 1865 Note: 1866 `PCGASMSetSubdomains()`, `PCGASMSetTotalSubdomains()` or `PCGASMSetOverlap()` take precedence over `PCGASMSetUseDMSubdomains()`, 1867 so setting `PCGASMSetSubdomains()` with nontrivial subdomain ISs or any of `PCGASMSetTotalSubdomains()` and `PCGASMSetOverlap()` 1868 automatically turns the latter off. 1869 1870 .seealso: [](ch_ksp), `PCGASM`, `PCGASMGetUseDMSubdomains()`, `PCGASMSetSubdomains()`, `PCGASMSetOverlap()` 1871 `PCGASMCreateSubdomains2D()` 1872 @*/ 1873 PetscErrorCode PCGASMSetUseDMSubdomains(PC pc, PetscBool flg) 1874 { 1875 PC_GASM *osm = (PC_GASM *)pc->data; 1876 PetscBool match; 1877 1878 PetscFunctionBegin; 1879 PetscValidHeaderSpecific(pc, PC_CLASSID, 1); 1880 PetscValidLogicalCollectiveBool(pc, flg, 2); 1881 PetscCheck(!pc->setupcalled, ((PetscObject)pc)->comm, PETSC_ERR_ARG_WRONGSTATE, "Not for a setup PC."); 1882 PetscCall(PetscObjectTypeCompare((PetscObject)pc, PCGASM, &match)); 1883 if (match) { 1884 if (!osm->user_subdomains && osm->N == PETSC_DETERMINE && osm->overlap < 0) osm->dm_subdomains = flg; 1885 } 1886 PetscFunctionReturn(PETSC_SUCCESS); 1887 } 1888 1889 /*@ 1890 PCGASMGetUseDMSubdomains - Returns flag indicating whether to use `DMCreateDomainDecomposition()` to define the subdomains, whenever possible with `PCGASM` 1891 1892 Not Collective 1893 1894 Input Parameter: 1895 . pc - the preconditioner 1896 1897 Output Parameter: 1898 . flg - boolean indicating whether to use subdomains defined by the `DM` 1899 1900 Level: intermediate 1901 1902 .seealso: [](ch_ksp), `PCGASM`, `PCGASMSetUseDMSubdomains()`, `PCGASMSetOverlap()` 1903 `PCGASMCreateSubdomains2D()` 1904 @*/ 1905 PetscErrorCode PCGASMGetUseDMSubdomains(PC pc, PetscBool *flg) 1906 { 1907 PC_GASM *osm = (PC_GASM *)pc->data; 1908 PetscBool match; 1909 1910 PetscFunctionBegin; 1911 PetscValidHeaderSpecific(pc, PC_CLASSID, 1); 1912 PetscAssertPointer(flg, 2); 1913 PetscCall(PetscObjectTypeCompare((PetscObject)pc, PCGASM, &match)); 1914 if (match) { 1915 if (flg) *flg = osm->dm_subdomains; 1916 } 1917 PetscFunctionReturn(PETSC_SUCCESS); 1918 } 1919