Actual source code: gasm.c
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*.
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>
12: #include <petscdm.h>
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;
39: static PetscErrorCode PCGASMComputeGlobalSubdomainNumbering_Private(PC pc, PetscInt **numbering, PetscInt **permutation)
40: {
41: PC_GASM *osm = (PC_GASM *)pc->data;
42: PetscInt i;
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: }
53: static PetscErrorCode PCGASMSubdomainView_Private(PC pc, PetscInt i, PetscViewer viewer)
54: {
55: PC_GASM *osm = (PC_GASM *)pc->data;
56: PetscInt nidx;
57: const PetscInt *idx;
58: PetscViewer sviewer;
59: char *cidx;
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);
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 (PetscInt 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));
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 (PetscInt 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: }
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 */
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: }
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 isascii, view_subdomains = PETSC_FALSE;
163: PetscViewer sviewer;
164: PetscInt 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 */
170: PetscFunctionBegin;
171: PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)pc), &size));
172: PetscCallMPI(MPI_Comm_rank(PetscObjectComm((PetscObject)pc), &rank));
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));
178: PetscCall(PCGetOptionsPrefix(pc, &prefix));
179: PetscCall(PetscOptionsGetBool(NULL, prefix, "-pc_gasm_view_subdomains", &view_subdomains, NULL));
181: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERASCII, &isascii));
182: if (isascii) {
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:\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 (PetscInt 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: }
245: PETSC_INTERN PetscErrorCode PCGASMCreateLocalSubdomains(Mat A, PetscInt nloc, IS *iis[]);
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;
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: }
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;
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: IS *inner_subdomain_is, *outer_subdomain_is;
335: PetscCall(DMCreateDomainDecomposition(pc->dm, &num_subdomains, &subdomain_names, &inner_subdomain_is, &outer_subdomain_is, &subdomain_dm));
336: if (num_subdomains) PetscCall(PCGASMSetSubdomains(pc, num_subdomains, inner_subdomain_is, outer_subdomain_is));
337: for (PetscInt d = 0; d < num_subdomains; ++d) {
338: if (inner_subdomain_is) PetscCall(ISDestroy(&inner_subdomain_is[d]));
339: if (outer_subdomain_is) PetscCall(ISDestroy(&outer_subdomain_is[d]));
340: }
341: PetscCall(PetscFree(inner_subdomain_is));
342: PetscCall(PetscFree(outer_subdomain_is));
343: } else {
344: /* still no subdomains; use one per rank */
345: osm->nmax = osm->n = 1;
346: PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)pc), &size));
347: osm->N = size;
348: PetscCall(PCGASMCreateLocalSubdomains(pc->pmat, osm->n, &osm->iis));
349: }
350: }
351: if (!osm->iis) {
352: /*
353: osm->n was set in PCGASMSetSubdomains(), but the actual subdomains have not been supplied.
354: We create the requisite number of local inner subdomains and then expand them into
355: out subdomains, if necessary.
356: */
357: PetscCall(PCGASMCreateLocalSubdomains(pc->pmat, osm->n, &osm->iis));
358: }
359: if (!osm->ois) {
360: /*
361: Initially make outer subdomains the same as inner subdomains. If nonzero additional overlap
362: has been requested, copy the inner subdomains over so they can be modified.
363: */
364: PetscCall(PetscMalloc1(osm->n, &osm->ois));
365: for (i = 0; i < osm->n; ++i) {
366: if (osm->overlap > 0 && osm->N > 1) { /* With positive overlap, osm->iis[i] will be modified */
367: PetscCall(ISDuplicate(osm->iis[i], (osm->ois) + i));
368: PetscCall(ISCopy(osm->iis[i], osm->ois[i]));
369: } else {
370: PetscCall(PetscObjectReference((PetscObject)osm->iis[i]));
371: osm->ois[i] = osm->iis[i];
372: }
373: }
374: if (osm->overlap > 0 && osm->N > 1) {
375: /* Extend the "overlapping" regions by a number of steps */
376: PetscCall(MatIncreaseOverlapSplit(pc->pmat, osm->n, osm->ois, osm->overlap));
377: }
378: }
380: /* Now the subdomains are defined. Determine their global and max local numbers, if necessary. */
381: if (osm->nmax == PETSC_DETERMINE) {
382: PetscInt inwork, outwork;
383: /* determine global number of subdomains and the max number of local subdomains */
384: inwork = osm->n;
385: PetscCallMPI(MPIU_Allreduce(&inwork, &outwork, 1, MPIU_INT, MPI_MAX, PetscObjectComm((PetscObject)pc)));
386: osm->nmax = outwork;
387: }
388: if (osm->N == PETSC_DETERMINE) {
389: /* Determine the number of globally-distinct subdomains and compute a global numbering for them. */
390: PetscCall(PetscObjectsListGetGlobalNumbering(PetscObjectComm((PetscObject)pc), osm->n, (PetscObject *)osm->ois, &osm->N, NULL));
391: }
393: if (osm->sort_indices) {
394: for (i = 0; i < osm->n; i++) {
395: PetscCall(ISSort(osm->ois[i]));
396: PetscCall(ISSort(osm->iis[i]));
397: }
398: }
399: PetscCall(PCGetOptionsPrefix(pc, &prefix));
400: PetscCall(PCGASMPrintSubdomains(pc));
402: /*
403: Merge the ISs, create merged vectors and restrictions.
404: */
405: /* Merge outer subdomain ISs and construct a restriction onto the disjoint union of local outer subdomains. */
406: on = 0;
407: for (i = 0; i < osm->n; i++) {
408: PetscCall(ISGetLocalSize(osm->ois[i], &oni));
409: on += oni;
410: }
411: PetscCall(PetscMalloc1(on, &oidx));
412: on = 0;
413: /* Merge local indices together */
414: for (i = 0; i < osm->n; i++) {
415: PetscCall(ISGetLocalSize(osm->ois[i], &oni));
416: PetscCall(ISGetIndices(osm->ois[i], &oidxi));
417: PetscCall(PetscArraycpy(oidx + on, oidxi, oni));
418: PetscCall(ISRestoreIndices(osm->ois[i], &oidxi));
419: on += oni;
420: }
421: PetscCall(ISCreateGeneral(((PetscObject)pc)->comm, on, oidx, PETSC_OWN_POINTER, &gois));
422: nTotalInnerIndices = 0;
423: for (i = 0; i < osm->n; i++) {
424: PetscCall(ISGetLocalSize(osm->iis[i], &nInnerIndices));
425: nTotalInnerIndices += nInnerIndices;
426: }
427: PetscCall(VecCreateMPI(((PetscObject)pc)->comm, nTotalInnerIndices, PETSC_DETERMINE, &x));
428: PetscCall(VecDuplicate(x, &y));
430: PetscCall(VecCreateMPI(PetscObjectComm((PetscObject)pc), on, PETSC_DECIDE, &osm->gx));
431: PetscCall(VecDuplicate(osm->gx, &osm->gy));
432: PetscCall(VecGetOwnershipRange(osm->gx, &gostart, NULL));
433: PetscCall(ISCreateStride(PetscObjectComm((PetscObject)pc), on, gostart, 1, &goid));
434: /* gois might indices not on local */
435: PetscCall(VecScatterCreate(x, gois, osm->gx, goid, &osm->gorestriction));
436: PetscCall(PetscMalloc1(osm->n, &numbering));
437: PetscCall(PetscObjectsListGetGlobalNumbering(PetscObjectComm((PetscObject)pc), osm->n, (PetscObject *)osm->ois, NULL, numbering));
438: PetscCall(VecDestroy(&x));
439: PetscCall(ISDestroy(&gois));
441: /* Merge inner subdomain ISs and construct a restriction onto the disjoint union of local inner subdomains. */
442: {
443: PetscInt ini; /* Number of indices the i-th a local inner subdomain. */
444: PetscInt in; /* Number of indices in the disjoint union of local inner subdomains. */
445: PetscInt *iidx; /* Global indices in the merged local inner subdomain. */
446: PetscInt *ioidx; /* Global indices of the disjoint union of inner subdomains within the disjoint union of outer subdomains. */
447: IS giis; /* IS for the disjoint union of inner subdomains. */
448: IS giois; /* IS for the disjoint union of inner subdomains within the disjoint union of outer subdomains. */
449: PetscScalar *array;
450: const PetscInt *indices;
451: on = 0;
452: for (i = 0; i < osm->n; i++) {
453: PetscCall(ISGetLocalSize(osm->ois[i], &oni));
454: on += oni;
455: }
456: PetscCall(PetscMalloc1(on, &iidx));
457: PetscCall(PetscMalloc1(on, &ioidx));
458: PetscCall(VecGetArray(y, &array));
459: /* set communicator id to determine where overlap is */
460: in = 0;
461: for (i = 0; i < osm->n; i++) {
462: PetscCall(ISGetLocalSize(osm->iis[i], &ini));
463: for (PetscInt k = 0; k < ini; ++k) array[in + k] = numbering[i];
464: in += ini;
465: }
466: PetscCall(VecRestoreArray(y, &array));
467: PetscCall(VecScatterBegin(osm->gorestriction, y, osm->gy, INSERT_VALUES, SCATTER_FORWARD));
468: PetscCall(VecScatterEnd(osm->gorestriction, y, osm->gy, INSERT_VALUES, SCATTER_FORWARD));
469: PetscCall(VecGetOwnershipRange(osm->gy, &gostart, NULL));
470: PetscCall(VecGetArray(osm->gy, &array));
471: on = 0;
472: in = 0;
473: for (i = 0; i < osm->n; i++) {
474: PetscCall(ISGetLocalSize(osm->ois[i], &oni));
475: PetscCall(ISGetIndices(osm->ois[i], &indices));
476: for (PetscInt k = 0; k < oni; k++) {
477: /* skip overlapping indices to get inner domain */
478: if (PetscRealPart(array[on + k]) != numbering[i]) continue;
479: iidx[in] = indices[k];
480: ioidx[in++] = gostart + on + k;
481: }
482: PetscCall(ISRestoreIndices(osm->ois[i], &indices));
483: on += oni;
484: }
485: PetscCall(VecRestoreArray(osm->gy, &array));
486: PetscCall(ISCreateGeneral(PetscObjectComm((PetscObject)pc), in, iidx, PETSC_OWN_POINTER, &giis));
487: PetscCall(ISCreateGeneral(PetscObjectComm((PetscObject)pc), in, ioidx, PETSC_OWN_POINTER, &giois));
488: PetscCall(VecScatterCreate(y, giis, osm->gy, giois, &osm->girestriction));
489: PetscCall(VecDestroy(&y));
490: PetscCall(ISDestroy(&giis));
491: PetscCall(ISDestroy(&giois));
492: }
493: PetscCall(ISDestroy(&goid));
494: PetscCall(PetscFree(numbering));
496: /* Create the subdomain work vectors. */
497: PetscCall(PetscMalloc1(osm->n, &osm->x));
498: PetscCall(PetscMalloc1(osm->n, &osm->y));
499: PetscCall(VecGetArray(osm->gx, &gxarray));
500: PetscCall(VecGetArray(osm->gy, &gyarray));
501: for (i = 0, on = 0; i < osm->n; ++i, on += oni) {
502: PetscInt oNi;
503: PetscCall(ISGetLocalSize(osm->ois[i], &oni));
504: /* on a sub communicator */
505: PetscCall(ISGetSize(osm->ois[i], &oNi));
506: PetscCall(VecCreateMPIWithArray(((PetscObject)osm->ois[i])->comm, 1, oni, oNi, gxarray + on, &osm->x[i]));
507: PetscCall(VecCreateMPIWithArray(((PetscObject)osm->ois[i])->comm, 1, oni, oNi, gyarray + on, &osm->y[i]));
508: }
509: PetscCall(VecRestoreArray(osm->gx, &gxarray));
510: PetscCall(VecRestoreArray(osm->gy, &gyarray));
511: /* Create the subdomain solvers */
512: PetscCall(PetscMalloc1(osm->n, &osm->ksp));
513: for (i = 0; i < osm->n; i++) {
514: char subprefix[PETSC_MAX_PATH_LEN + 1];
515: PetscCall(KSPCreate(((PetscObject)osm->ois[i])->comm, &ksp));
516: PetscCall(KSPSetNestLevel(ksp, pc->kspnestlevel));
517: PetscCall(KSPSetErrorIfNotConverged(ksp, pc->erroriffailure));
518: PetscCall(PetscObjectIncrementTabLevel((PetscObject)ksp, (PetscObject)pc, 1));
519: PetscCall(KSPSetType(ksp, KSPPREONLY));
520: PetscCall(KSPGetPC(ksp, &subpc)); /* Why do we need this here? */
521: if (subdomain_dm) {
522: PetscCall(KSPSetDM(ksp, subdomain_dm[i]));
523: PetscCall(DMDestroy(subdomain_dm + i));
524: }
525: PetscCall(PCGetOptionsPrefix(pc, &prefix));
526: PetscCall(KSPSetOptionsPrefix(ksp, prefix));
527: if (subdomain_names && subdomain_names[i]) {
528: PetscCall(PetscSNPrintf(subprefix, PETSC_MAX_PATH_LEN, "sub_%s_", subdomain_names[i]));
529: PetscCall(KSPAppendOptionsPrefix(ksp, subprefix));
530: PetscCall(PetscFree(subdomain_names[i]));
531: }
532: PetscCall(KSPAppendOptionsPrefix(ksp, "sub_"));
533: osm->ksp[i] = ksp;
534: }
535: PetscCall(PetscFree(subdomain_dm));
536: PetscCall(PetscFree(subdomain_names));
537: scall = MAT_INITIAL_MATRIX;
538: } else { /* if (pc->setupcalled) */
539: /*
540: Destroy the submatrices from the previous iteration
541: */
542: if (pc->flag == DIFFERENT_NONZERO_PATTERN) {
543: PetscCall(MatDestroyMatrices(osm->n, &osm->pmat));
544: scall = MAT_INITIAL_MATRIX;
545: }
546: if (osm->permutationIS) {
547: PetscCall(MatCreateSubMatrix(pc->pmat, osm->permutationIS, osm->permutationIS, scall, &osm->permutationP));
548: PetscCall(PetscObjectReference((PetscObject)osm->permutationP));
549: osm->pcmat = pc->pmat;
550: pc->pmat = osm->permutationP;
551: }
552: }
554: /*
555: Extract the submatrices.
556: */
557: if (size > 1) {
558: PetscCall(MatCreateSubMatricesMPI(pc->pmat, osm->n, osm->ois, osm->ois, scall, &osm->pmat));
559: } else {
560: PetscCall(MatCreateSubMatrices(pc->pmat, osm->n, osm->ois, osm->ois, scall, &osm->pmat));
561: }
562: if (scall == MAT_INITIAL_MATRIX) {
563: PetscCall(PetscObjectGetOptionsPrefix((PetscObject)pc->pmat, &pprefix));
564: for (i = 0; i < osm->n; i++) PetscCall(PetscObjectSetOptionsPrefix((PetscObject)osm->pmat[i], pprefix));
565: }
567: /* Return control to the user so that the submatrices can be modified (e.g., to apply
568: different boundary conditions for the submatrices than for the global problem) */
569: PetscCall(PCModifySubMatrices(pc, osm->n, osm->ois, osm->ois, osm->pmat, pc->modifysubmatricesP));
571: /*
572: Loop over submatrices putting them into local ksps
573: */
574: for (i = 0; i < osm->n; i++) {
575: PetscCall(KSPSetOperators(osm->ksp[i], osm->pmat[i], osm->pmat[i]));
576: PetscCall(KSPGetOptionsPrefix(osm->ksp[i], &prefix));
577: PetscCall(MatSetOptionsPrefix(osm->pmat[i], prefix));
578: if (!pc->setupcalled) PetscCall(KSPSetFromOptions(osm->ksp[i]));
579: }
580: if (osm->pcmat) {
581: PetscCall(MatDestroy(&pc->pmat));
582: pc->pmat = osm->pcmat;
583: osm->pcmat = NULL;
584: }
585: PetscFunctionReturn(PETSC_SUCCESS);
586: }
588: static PetscErrorCode PCSetUpOnBlocks_GASM(PC pc)
589: {
590: PC_GASM *osm = (PC_GASM *)pc->data;
591: PetscInt i;
593: PetscFunctionBegin;
594: for (i = 0; i < osm->n; i++) PetscCall(KSPSetUp(osm->ksp[i]));
595: PetscFunctionReturn(PETSC_SUCCESS);
596: }
598: static PetscErrorCode PCApply_GASM(PC pc, Vec xin, Vec yout)
599: {
600: PC_GASM *osm = (PC_GASM *)pc->data;
601: PetscInt i;
602: Vec x, y;
603: ScatterMode forward = SCATTER_FORWARD, reverse = SCATTER_REVERSE;
605: PetscFunctionBegin;
606: if (osm->pctoouter) {
607: PetscCall(VecScatterBegin(osm->pctoouter, xin, osm->pcx, INSERT_VALUES, SCATTER_REVERSE));
608: PetscCall(VecScatterEnd(osm->pctoouter, xin, osm->pcx, INSERT_VALUES, SCATTER_REVERSE));
609: x = osm->pcx;
610: y = osm->pcy;
611: } else {
612: x = xin;
613: y = yout;
614: }
615: /*
616: support for limiting the restriction or interpolation only to the inner
617: subdomain values (leaving the other values 0).
618: */
619: if (!(osm->type & PC_GASM_RESTRICT)) {
620: /* have to zero the work RHS since scatter may leave some slots empty */
621: PetscCall(VecZeroEntries(osm->gx));
622: PetscCall(VecScatterBegin(osm->girestriction, x, osm->gx, INSERT_VALUES, forward));
623: } else {
624: PetscCall(VecScatterBegin(osm->gorestriction, x, osm->gx, INSERT_VALUES, forward));
625: }
626: PetscCall(VecZeroEntries(osm->gy));
627: if (!(osm->type & PC_GASM_RESTRICT)) {
628: PetscCall(VecScatterEnd(osm->girestriction, x, osm->gx, INSERT_VALUES, forward));
629: } else {
630: PetscCall(VecScatterEnd(osm->gorestriction, x, osm->gx, INSERT_VALUES, forward));
631: }
632: /* do the subdomain solves */
633: for (i = 0; i < osm->n; ++i) {
634: PetscCall(KSPSolve(osm->ksp[i], osm->x[i], osm->y[i]));
635: PetscCall(KSPCheckSolve(osm->ksp[i], pc, osm->y[i]));
636: }
637: /* do we need to zero y? */
638: PetscCall(VecZeroEntries(y));
639: if (!(osm->type & PC_GASM_INTERPOLATE)) {
640: PetscCall(VecScatterBegin(osm->girestriction, osm->gy, y, ADD_VALUES, reverse));
641: PetscCall(VecScatterEnd(osm->girestriction, osm->gy, y, ADD_VALUES, reverse));
642: } else {
643: PetscCall(VecScatterBegin(osm->gorestriction, osm->gy, y, ADD_VALUES, reverse));
644: PetscCall(VecScatterEnd(osm->gorestriction, osm->gy, y, ADD_VALUES, reverse));
645: }
646: if (osm->pctoouter) {
647: PetscCall(VecScatterBegin(osm->pctoouter, y, yout, INSERT_VALUES, SCATTER_FORWARD));
648: PetscCall(VecScatterEnd(osm->pctoouter, y, yout, INSERT_VALUES, SCATTER_FORWARD));
649: }
650: PetscFunctionReturn(PETSC_SUCCESS);
651: }
653: static PetscErrorCode PCMatApply_GASM(PC pc, Mat Xin, Mat Yout)
654: {
655: PC_GASM *osm = (PC_GASM *)pc->data;
656: Mat X, Y, O = NULL, Z, W;
657: Vec x, y;
658: PetscInt i, m, M, N;
659: ScatterMode forward = SCATTER_FORWARD, reverse = SCATTER_REVERSE;
661: PetscFunctionBegin;
662: PetscCheck(osm->n == 1, PetscObjectComm((PetscObject)pc), PETSC_ERR_SUP, "Not yet implemented");
663: PetscCall(MatGetSize(Xin, NULL, &N));
664: if (osm->pctoouter) {
665: PetscCall(VecGetLocalSize(osm->pcx, &m));
666: PetscCall(VecGetSize(osm->pcx, &M));
667: PetscCall(MatCreateDense(PetscObjectComm((PetscObject)osm->ois[0]), m, PETSC_DECIDE, M, N, NULL, &O));
668: for (i = 0; i < N; ++i) {
669: PetscCall(MatDenseGetColumnVecRead(Xin, i, &x));
670: PetscCall(MatDenseGetColumnVecWrite(O, i, &y));
671: PetscCall(VecScatterBegin(osm->pctoouter, x, y, INSERT_VALUES, SCATTER_REVERSE));
672: PetscCall(VecScatterEnd(osm->pctoouter, x, y, INSERT_VALUES, SCATTER_REVERSE));
673: PetscCall(MatDenseRestoreColumnVecWrite(O, i, &y));
674: PetscCall(MatDenseRestoreColumnVecRead(Xin, i, &x));
675: }
676: X = Y = O;
677: } else {
678: X = Xin;
679: Y = Yout;
680: }
681: /*
682: support for limiting the restriction or interpolation only to the inner
683: subdomain values (leaving the other values 0).
684: */
685: PetscCall(VecGetLocalSize(osm->x[0], &m));
686: PetscCall(VecGetSize(osm->x[0], &M));
687: PetscCall(MatCreateDense(PetscObjectComm((PetscObject)osm->ois[0]), m, PETSC_DECIDE, M, N, NULL, &Z));
688: for (i = 0; i < N; ++i) {
689: PetscCall(MatDenseGetColumnVecRead(X, i, &x));
690: PetscCall(MatDenseGetColumnVecWrite(Z, i, &y));
691: if (!(osm->type & PC_GASM_RESTRICT)) {
692: /* have to zero the work RHS since scatter may leave some slots empty */
693: PetscCall(VecZeroEntries(y));
694: PetscCall(VecScatterBegin(osm->girestriction, x, y, INSERT_VALUES, forward));
695: PetscCall(VecScatterEnd(osm->girestriction, x, y, INSERT_VALUES, forward));
696: } else {
697: PetscCall(VecScatterBegin(osm->gorestriction, x, y, INSERT_VALUES, forward));
698: PetscCall(VecScatterEnd(osm->gorestriction, x, y, INSERT_VALUES, forward));
699: }
700: PetscCall(MatDenseRestoreColumnVecWrite(Z, i, &y));
701: PetscCall(MatDenseRestoreColumnVecRead(X, i, &x));
702: }
703: PetscCall(MatCreateDense(PetscObjectComm((PetscObject)osm->ois[0]), m, PETSC_DECIDE, M, N, NULL, &W));
704: PetscCall(MatSetOption(Z, MAT_NO_OFF_PROC_ENTRIES, PETSC_TRUE));
705: PetscCall(MatAssemblyBegin(Z, MAT_FINAL_ASSEMBLY));
706: PetscCall(MatAssemblyEnd(Z, MAT_FINAL_ASSEMBLY));
707: /* do the subdomain solve */
708: PetscCall(KSPMatSolve(osm->ksp[0], Z, W));
709: PetscCall(KSPCheckSolve(osm->ksp[0], pc, NULL));
710: PetscCall(MatDestroy(&Z));
711: /* do we need to zero y? */
712: PetscCall(MatZeroEntries(Y));
713: for (i = 0; i < N; ++i) {
714: PetscCall(MatDenseGetColumnVecWrite(Y, i, &y));
715: PetscCall(MatDenseGetColumnVecRead(W, i, &x));
716: if (!(osm->type & PC_GASM_INTERPOLATE)) {
717: PetscCall(VecScatterBegin(osm->girestriction, x, y, ADD_VALUES, reverse));
718: PetscCall(VecScatterEnd(osm->girestriction, x, y, ADD_VALUES, reverse));
719: } else {
720: PetscCall(VecScatterBegin(osm->gorestriction, x, y, ADD_VALUES, reverse));
721: PetscCall(VecScatterEnd(osm->gorestriction, x, y, ADD_VALUES, reverse));
722: }
723: PetscCall(MatDenseRestoreColumnVecRead(W, i, &x));
724: if (osm->pctoouter) {
725: PetscCall(MatDenseGetColumnVecWrite(Yout, i, &x));
726: PetscCall(VecScatterBegin(osm->pctoouter, y, x, INSERT_VALUES, SCATTER_FORWARD));
727: PetscCall(VecScatterEnd(osm->pctoouter, y, x, INSERT_VALUES, SCATTER_FORWARD));
728: PetscCall(MatDenseRestoreColumnVecRead(Yout, i, &x));
729: }
730: PetscCall(MatDenseRestoreColumnVecWrite(Y, i, &y));
731: }
732: PetscCall(MatDestroy(&W));
733: PetscCall(MatDestroy(&O));
734: PetscFunctionReturn(PETSC_SUCCESS);
735: }
737: static PetscErrorCode PCApplyTranspose_GASM(PC pc, Vec xin, Vec yout)
738: {
739: PC_GASM *osm = (PC_GASM *)pc->data;
740: PetscInt i;
741: Vec x, y;
742: ScatterMode forward = SCATTER_FORWARD, reverse = SCATTER_REVERSE;
744: PetscFunctionBegin;
745: if (osm->pctoouter) {
746: PetscCall(VecScatterBegin(osm->pctoouter, xin, osm->pcx, INSERT_VALUES, SCATTER_REVERSE));
747: PetscCall(VecScatterEnd(osm->pctoouter, xin, osm->pcx, INSERT_VALUES, SCATTER_REVERSE));
748: x = osm->pcx;
749: y = osm->pcy;
750: } else {
751: x = xin;
752: y = yout;
753: }
754: /*
755: Support for limiting the restriction or interpolation to only local
756: subdomain values (leaving the other values 0).
758: Note: these are reversed from the PCApply_GASM() because we are applying the
759: transpose of the three terms
760: */
761: if (!(osm->type & PC_GASM_INTERPOLATE)) {
762: /* have to zero the work RHS since scatter may leave some slots empty */
763: PetscCall(VecZeroEntries(osm->gx));
764: PetscCall(VecScatterBegin(osm->girestriction, x, osm->gx, INSERT_VALUES, forward));
765: } else {
766: PetscCall(VecScatterBegin(osm->gorestriction, x, osm->gx, INSERT_VALUES, forward));
767: }
768: PetscCall(VecZeroEntries(osm->gy));
769: if (!(osm->type & PC_GASM_INTERPOLATE)) {
770: PetscCall(VecScatterEnd(osm->girestriction, x, osm->gx, INSERT_VALUES, forward));
771: } else {
772: PetscCall(VecScatterEnd(osm->gorestriction, x, osm->gx, INSERT_VALUES, forward));
773: }
774: /* do the local solves */
775: for (i = 0; i < osm->n; ++i) { /* Note that the solves are local, so we can go to osm->n, rather than osm->nmax. */
776: PetscCall(KSPSolveTranspose(osm->ksp[i], osm->x[i], osm->y[i]));
777: PetscCall(KSPCheckSolve(osm->ksp[i], pc, osm->y[i]));
778: }
779: PetscCall(VecZeroEntries(y));
780: if (!(osm->type & PC_GASM_RESTRICT)) {
781: PetscCall(VecScatterBegin(osm->girestriction, osm->gy, y, ADD_VALUES, reverse));
782: PetscCall(VecScatterEnd(osm->girestriction, osm->gy, y, ADD_VALUES, reverse));
783: } else {
784: PetscCall(VecScatterBegin(osm->gorestriction, osm->gy, y, ADD_VALUES, reverse));
785: PetscCall(VecScatterEnd(osm->gorestriction, osm->gy, y, ADD_VALUES, reverse));
786: }
787: if (osm->pctoouter) {
788: PetscCall(VecScatterBegin(osm->pctoouter, y, yout, INSERT_VALUES, SCATTER_FORWARD));
789: PetscCall(VecScatterEnd(osm->pctoouter, y, yout, INSERT_VALUES, SCATTER_FORWARD));
790: }
791: PetscFunctionReturn(PETSC_SUCCESS);
792: }
794: static PetscErrorCode PCReset_GASM(PC pc)
795: {
796: PC_GASM *osm = (PC_GASM *)pc->data;
798: PetscFunctionBegin;
799: if (osm->ksp) {
800: for (PetscInt i = 0; i < osm->n; i++) PetscCall(KSPReset(osm->ksp[i]));
801: }
802: if (osm->pmat) {
803: if (osm->n > 0) {
804: PetscMPIInt size;
805: PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)pc), &size));
806: if (size > 1) {
807: /* osm->pmat is created by MatCreateSubMatricesMPI(), cannot use MatDestroySubMatrices() */
808: PetscCall(MatDestroyMatrices(osm->n, &osm->pmat));
809: } else {
810: PetscCall(MatDestroySubMatrices(osm->n, &osm->pmat));
811: }
812: }
813: }
814: if (osm->x) {
815: for (PetscInt i = 0; i < osm->n; i++) {
816: PetscCall(VecDestroy(&osm->x[i]));
817: PetscCall(VecDestroy(&osm->y[i]));
818: }
819: }
820: PetscCall(VecDestroy(&osm->gx));
821: PetscCall(VecDestroy(&osm->gy));
823: PetscCall(VecScatterDestroy(&osm->gorestriction));
824: PetscCall(VecScatterDestroy(&osm->girestriction));
825: if (!osm->user_subdomains) {
826: PetscCall(PCGASMDestroySubdomains(osm->n, &osm->ois, &osm->iis));
827: osm->N = PETSC_DETERMINE;
828: osm->nmax = PETSC_DETERMINE;
829: }
830: PetscCall(VecScatterDestroy(&osm->pctoouter));
831: PetscCall(ISDestroy(&osm->permutationIS));
832: PetscCall(VecDestroy(&osm->pcx));
833: PetscCall(VecDestroy(&osm->pcy));
834: PetscCall(MatDestroy(&osm->permutationP));
835: PetscCall(MatDestroy(&osm->pcmat));
836: PetscFunctionReturn(PETSC_SUCCESS);
837: }
839: static PetscErrorCode PCDestroy_GASM(PC pc)
840: {
841: PC_GASM *osm = (PC_GASM *)pc->data;
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 (PetscInt 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: }
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;
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: }
887: /*@
888: PCGASMSetTotalSubdomains - sets the total number of subdomains to use across the communicator for `PCGASM`
890: Logically Collective
892: Input Parameters:
893: + pc - the preconditioner
894: - N - total number of subdomains
896: Level: beginner
898: .seealso: [](ch_ksp), `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;
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().");
910: PetscCall(PCGASMDestroySubdomains(osm->n, &osm->iis, &osm->ois));
911: osm->ois = osm->iis = NULL;
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: }
922: static PetscErrorCode PCGASMSetSubdomains_GASM(PC pc, PetscInt n, IS iis[], IS ois[])
923: {
924: PC_GASM *osm = (PC_GASM *)pc->data;
926: PetscFunctionBegin;
927: PetscCheck(n >= 1, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Each MPI rank must have 1 or more subdomains, got n = %" PetscInt_FMT, n);
928: PetscCheck(!pc->setupcalled, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONGSTATE, "PCGASMSetSubdomains() should be called before calling PCSetUp().");
930: PetscCall(PCGASMDestroySubdomains(osm->n, &osm->iis, &osm->ois));
931: osm->iis = osm->ois = NULL;
932: osm->n = n;
933: osm->N = PETSC_DETERMINE;
934: osm->nmax = PETSC_DETERMINE;
935: if (ois) {
936: PetscCall(PetscMalloc1(n, &osm->ois));
937: for (PetscInt i = 0; i < n; i++) {
938: PetscCall(PetscObjectReference((PetscObject)ois[i]));
939: osm->ois[i] = ois[i];
940: }
941: /*
942: Since the user set the outer subdomains, even if nontrivial overlap was requested via PCGASMSetOverlap(),
943: it will be ignored. To avoid confusion later on (e.g., when viewing the PC), the overlap size is set to -1.
944: */
945: osm->overlap = -1;
946: /* inner subdomains must be provided */
947: PetscCheck(iis, PETSC_COMM_SELF, PETSC_ERR_ARG_NULL, "inner indices have to be provided ");
948: } /* end if */
949: if (iis) {
950: PetscCall(PetscMalloc1(n, &osm->iis));
951: for (PetscInt i = 0; i < n; i++) {
952: PetscCall(PetscObjectReference((PetscObject)iis[i]));
953: osm->iis[i] = iis[i];
954: }
955: if (!ois) {
956: osm->ois = NULL;
957: /* if user does not provide outer indices, we will create the corresponding outer indices using osm->overlap =1 in PCSetUp_GASM */
958: }
959: }
960: if (PetscDefined(USE_DEBUG)) {
961: PetscInt j, rstart, rend, *covered, lsize;
962: const PetscInt *indices;
964: if (osm->iis) {
965: /* check if the inner indices cover and only cover the local portion of the matrix */
966: PetscCall(MatGetOwnershipRange(pc->pmat, &rstart, &rend));
967: PetscCall(PetscCalloc1(rend - rstart, &covered));
968: /* check if the current MPI process owns indices from others */
969: for (PetscInt i = 0; i < n; i++) {
970: PetscCall(ISGetIndices(osm->iis[i], &indices));
971: PetscCall(ISGetLocalSize(osm->iis[i], &lsize));
972: for (j = 0; j < lsize; j++) {
973: 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]);
974: 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]);
975: covered[indices[j] - rstart] = 1;
976: }
977: PetscCall(ISRestoreIndices(osm->iis[i], &indices));
978: }
979: /* check if we miss any indices */
980: for (PetscInt 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);
981: PetscCall(PetscFree(covered));
982: }
983: }
984: if (iis) osm->user_subdomains = PETSC_TRUE;
985: PetscFunctionReturn(PETSC_SUCCESS);
986: }
988: static PetscErrorCode PCGASMSetOverlap_GASM(PC pc, PetscInt ovl)
989: {
990: PC_GASM *osm = (PC_GASM *)pc->data;
992: PetscFunctionBegin;
993: PetscCheck(ovl >= 0, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_OUTOFRANGE, "Negative overlap value requested");
994: PetscCheck(!pc->setupcalled || ovl == osm->overlap, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONGSTATE, "PCGASMSetOverlap() should be called before PCSetUp().");
995: if (!pc->setupcalled) osm->overlap = ovl;
996: PetscFunctionReturn(PETSC_SUCCESS);
997: }
999: static PetscErrorCode PCGASMSetType_GASM(PC pc, PCGASMType type)
1000: {
1001: PC_GASM *osm = (PC_GASM *)pc->data;
1003: PetscFunctionBegin;
1004: osm->type = type;
1005: osm->type_set = PETSC_TRUE;
1006: PetscFunctionReturn(PETSC_SUCCESS);
1007: }
1009: static PetscErrorCode PCGASMSetSortIndices_GASM(PC pc, PetscBool doSort)
1010: {
1011: PC_GASM *osm = (PC_GASM *)pc->data;
1013: PetscFunctionBegin;
1014: osm->sort_indices = doSort;
1015: PetscFunctionReturn(PETSC_SUCCESS);
1016: }
1018: /*
1019: FIXME: This routine might need to be modified now that multiple processes per subdomain are allowed.
1020: In particular, it would upset the global subdomain number calculation.
1021: */
1022: static PetscErrorCode PCGASMGetSubKSP_GASM(PC pc, PetscInt *n, PetscInt *first, KSP **ksp)
1023: {
1024: PC_GASM *osm = (PC_GASM *)pc->data;
1026: PetscFunctionBegin;
1027: 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");
1029: if (n) *n = osm->n;
1030: if (first) {
1031: PetscCallMPI(MPI_Scan(&osm->n, first, 1, MPIU_INT, MPI_SUM, PetscObjectComm((PetscObject)pc)));
1032: *first -= osm->n;
1033: }
1034: if (ksp) {
1035: /* Assume that local solves are now different; not necessarily
1036: true, though! This flag is used only for PCView_GASM() */
1037: *ksp = osm->ksp;
1038: osm->same_subdomain_solvers = PETSC_FALSE;
1039: }
1040: PetscFunctionReturn(PETSC_SUCCESS);
1041: } /* PCGASMGetSubKSP_GASM() */
1043: /*@
1044: PCGASMSetSubdomains - Sets the subdomains for this MPI process
1045: for the additive Schwarz preconditioner with multiple MPI processes per subdomain, `PCGASM`
1047: Collective
1049: Input Parameters:
1050: + pc - the preconditioner object
1051: . n - the number of subdomains for this MPI process
1052: . iis - the index sets that define the inner subdomains (or `NULL` for PETSc to determine subdomains), the `iis` array is
1053: copied so may be freed after this call.
1054: - ois - the index sets that define the outer subdomains (or `NULL` to use the same as `iis`, or to construct by expanding `iis` by
1055: the requested overlap), the `ois` array is copied so may be freed after this call.
1057: Level: advanced
1059: Notes:
1060: The `IS` indices use the parallel, global numbering of the vector entries.
1062: Inner subdomains are those where the correction is applied.
1064: Outer subdomains are those where the residual necessary to obtain the
1065: corrections is obtained (see `PCGASMType` for the use of inner/outer subdomains).
1067: Both inner and outer subdomains can extend over several MPI processes.
1068: This process' portion of a subdomain is known as a local subdomain.
1070: Inner subdomains can not overlap with each other, do not have any entities from remote processes,
1071: and have to cover the entire local subdomain owned by the current process. The index sets on each
1072: process should be ordered such that the ith local subdomain is connected to the ith remote subdomain
1073: on another MPI process.
1075: By default the `PGASM` preconditioner uses 1 (local) subdomain per MPI process.
1077: The `iis` and `ois` arrays may be freed after this call using `PCGASMDestroySubdomains()`
1079: .seealso: [](ch_ksp), `PCGASM`, `PCGASMSetOverlap()`, `PCGASMGetSubKSP()`, `PCGASMDestroySubdomains()`,
1080: `PCGASMCreateSubdomains2D()`, `PCGASMGetSubdomains()`
1081: @*/
1082: PetscErrorCode PCGASMSetSubdomains(PC pc, PetscInt n, IS iis[], IS ois[])
1083: {
1084: PC_GASM *osm = (PC_GASM *)pc->data;
1086: PetscFunctionBegin;
1088: PetscTryMethod(pc, "PCGASMSetSubdomains_C", (PC, PetscInt, IS[], IS[]), (pc, n, iis, ois));
1089: osm->dm_subdomains = PETSC_FALSE;
1090: PetscFunctionReturn(PETSC_SUCCESS);
1091: }
1093: /*@
1094: PCGASMSetOverlap - Sets the overlap between a pair of subdomains for the
1095: additive Schwarz preconditioner `PCGASM`. Either all or no MPI processes in the
1096: pc communicator must call this routine.
1098: Logically Collective
1100: Input Parameters:
1101: + pc - the preconditioner context
1102: - ovl - the amount of overlap between subdomains (ovl >= 0, default value = 0)
1104: Options Database Key:
1105: . -pc_gasm_overlap overlap - Sets overlap
1107: Level: intermediate
1109: Notes:
1110: By default the `PCGASM` preconditioner uses 1 subdomain per process. To use
1111: multiple subdomain per perocessor or "straddling" subdomains that intersect
1112: multiple processes use `PCGASMSetSubdomains()` (or option `-pc_gasm_total_subdomains` <n>).
1114: The overlap defaults to 0, so if one desires that no additional
1115: overlap be computed beyond what may have been set with a call to
1116: `PCGASMSetSubdomains()`, then `ovl` must be set to be 0. In particular, if one does
1117: not explicitly set the subdomains in application code, then all overlap would be computed
1118: internally by PETSc, and using an overlap of 0 would result in an `PCGASM`
1119: variant that is equivalent to the block Jacobi preconditioner.
1121: One can define initial index sets with any overlap via
1122: `PCGASMSetSubdomains()`; the routine `PCGASMSetOverlap()` merely allows
1123: PETSc to extend that overlap further, if desired.
1125: .seealso: [](ch_ksp), `PCGASM`, `PCGASMSetSubdomains()`, `PCGASMGetSubKSP()`,
1126: `PCGASMCreateSubdomains2D()`, `PCGASMGetSubdomains()`
1127: @*/
1128: PetscErrorCode PCGASMSetOverlap(PC pc, PetscInt ovl)
1129: {
1130: PC_GASM *osm = (PC_GASM *)pc->data;
1132: PetscFunctionBegin;
1135: PetscTryMethod(pc, "PCGASMSetOverlap_C", (PC, PetscInt), (pc, ovl));
1136: osm->dm_subdomains = PETSC_FALSE;
1137: PetscFunctionReturn(PETSC_SUCCESS);
1138: }
1140: /*@
1141: PCGASMSetType - Sets the type of restriction and interpolation used
1142: for local problems in the `PCGASM` additive Schwarz method.
1144: Logically Collective
1146: Input Parameters:
1147: + pc - the preconditioner context
1148: - type - variant of `PCGASM`, one of
1149: .vb
1150: `PC_GASM_BASIC` - full interpolation and restriction
1151: `PC_GASM_RESTRICT` - full restriction, local MPI process interpolation
1152: `PC_GASM_INTERPOLATE` - full interpolation, local MPI process restriction
1153: `PC_GASM_NONE` - local MPI process restriction and interpolation
1154: .ve
1156: Options Database Key:
1157: . -pc_gasm_type [basic,restrict,interpolate,none] - Sets `PCGASM` type
1159: Level: intermediate
1161: .seealso: [](ch_ksp), `PCGASM`, `PCGASMSetSubdomains()`, `PCGASMGetSubKSP()`,
1162: `PCGASMCreateSubdomains2D()`, `PCASM`, `PCASMSetType()`
1163: @*/
1164: PetscErrorCode PCGASMSetType(PC pc, PCGASMType type)
1165: {
1166: PetscFunctionBegin;
1169: PetscTryMethod(pc, "PCGASMSetType_C", (PC, PCGASMType), (pc, type));
1170: PetscFunctionReturn(PETSC_SUCCESS);
1171: }
1173: /*@
1174: PCGASMSetSortIndices - Determines whether subdomain indices are sorted.
1176: Logically Collective
1178: Input Parameters:
1179: + pc - the preconditioner context
1180: - doSort - sort the subdomain indices
1182: Level: intermediate
1184: .seealso: [](ch_ksp), `PCGASM`, `PCGASMSetSubdomains()`, `PCGASMGetSubKSP()`,
1185: `PCGASMCreateSubdomains2D()`
1186: @*/
1187: PetscErrorCode PCGASMSetSortIndices(PC pc, PetscBool doSort)
1188: {
1189: PetscFunctionBegin;
1192: PetscTryMethod(pc, "PCGASMSetSortIndices_C", (PC, PetscBool), (pc, doSort));
1193: PetscFunctionReturn(PETSC_SUCCESS);
1194: }
1196: /*@C
1197: PCGASMGetSubKSP - Gets the local `KSP` contexts for all subdomains on this MPI process.
1199: Collective iff first_local is requested
1201: Input Parameter:
1202: . pc - the preconditioner context
1204: Output Parameters:
1205: + n_local - the number of blocks on this MPI process or `NULL`
1206: . first_local - the global number of the first block on this process or `NULL`, all processes must request or all must pass `NULL`
1207: - ksp - the array of `KSP` contexts
1209: Level: advanced
1211: Note:
1212: After `PCGASMGetSubKSP()` the array of `KSP`es is not to be freed
1214: Currently for some matrix implementations only 1 block per MPI process
1215: is supported.
1217: You must call `KSPSetUp()` before calling `PCGASMGetSubKSP()`.
1219: Fortran Note:
1220: Call `PCGASMRestoreSubKSP()` when the array of `KSP` is no longer needed
1222: .seealso: [](ch_ksp), `PCGASM`, `PCGASMSetSubdomains()`, `PCGASMSetOverlap()`,
1223: `PCGASMCreateSubdomains2D()`
1224: @*/
1225: PetscErrorCode PCGASMGetSubKSP(PC pc, PetscInt *n_local, PetscInt *first_local, KSP *ksp[])
1226: {
1227: PetscFunctionBegin;
1229: PetscUseMethod(pc, "PCGASMGetSubKSP_C", (PC, PetscInt *, PetscInt *, KSP **), (pc, n_local, first_local, ksp));
1230: PetscFunctionReturn(PETSC_SUCCESS);
1231: }
1233: /*MC
1234: PCGASM - Use the (restricted) additive Schwarz method, each block is (approximately) solved with
1235: its own `KSP` object on a subset of MPI processes
1237: Options Database Keys:
1238: + -pc_gasm_total_subdomains n - Sets total number of local subdomains to be distributed among the MPI processes
1239: . -pc_gasm_view_subdomains - activates the printing of subdomain indices in `PCView()`, -ksp_view or -snes_view
1240: . -pc_gasm_print_subdomains - activates the printing of subdomain indices in `PCSetUp()`
1241: . -pc_gasm_overlap ovl - Sets overlap by which to (automatically) extend local subdomains
1242: - -pc_gasm_type (basic|restrict|interpolate|none) - Sets `PCGASMType`
1244: Level: beginner
1246: Notes:
1247: To set options on the solvers for each block append `-sub_` to all the `KSP`, and `PC`
1248: options database keys. For example, `-sub_pc_type ilu -sub_pc_factor_levels 1 -sub_ksp_type preonly`
1250: To set the options on the solvers separate for each block call `PCGASMGetSubKSP()`
1251: and set the options directly on the resulting `KSP` object (you can access its `PC`
1252: with `KSPGetPC()`)
1254: See {cite}`dryja1987additive` and {cite}`1sbg` for details on additive Schwarz algorithms
1256: .seealso: [](ch_ksp), `PCCreate()`, `PCSetType()`, `PCType`, `PC`, `PCASM`, `PCGASMType`, `PCGASMSetType()`,
1257: `PCBJACOBI`, `PCGASMGetSubKSP()`, `PCGASMSetSubdomains()`,
1258: `PCSetModifySubMatrices()`, `PCGASMSetOverlap()`, `PCASMSetType()`
1259: M*/
1261: PETSC_EXTERN PetscErrorCode PCCreate_GASM(PC pc)
1262: {
1263: PC_GASM *osm;
1265: PetscFunctionBegin;
1266: PetscCall(PetscNew(&osm));
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;
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;
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: }
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;
1323: PetscFunctionBegin;
1324: PetscCheck(nloc >= 1, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "number of local subdomains must > 0, got nloc = %" PetscInt_FMT, nloc);
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);
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 */
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: }
1409: } else {
1410: /* Partitioning by adjacency of diagonal block */
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;
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: }
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: }
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: }
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.
1466: Collective
1468: Input Parameters:
1469: + A - The global matrix operator
1470: - N - the number of global subdomains requested
1472: Output Parameters:
1473: + n - the number of subdomains created on this MPI process
1474: - iis - the array of index sets defining the local inner subdomains (on which the correction is applied)
1476: Level: advanced
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' (process 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.
1485: Use `PCGASMDestroySubdomains()` to free the array and the list of index sets.
1487: .seealso: [](ch_ksp), `PCGASM`, `PCGASMSetSubdomains()`, `PCGASMDestroySubdomains()`
1488: @*/
1489: PetscErrorCode PCGASMCreateSubdomains(Mat A, PetscInt N, PetscInt *n, IS *iis[])
1490: {
1491: PetscMPIInt size;
1493: PetscFunctionBegin;
1495: PetscAssertPointer(iis, 4);
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: }
1508: /*@C
1509: PCGASMDestroySubdomains - Destroys the index sets created with
1510: `PCGASMCreateSubdomains()` or `PCGASMCreateSubdomains2D()`. Should be
1511: called after setting subdomains with `PCGASMSetSubdomains()`.
1513: Collective
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`
1520: Level: intermediate
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`.
1527: .seealso: [](ch_ksp), `PCGASM`, `PCGASMCreateSubdomains()`, `PCGASMSetSubdomains()`
1528: @*/
1529: PetscErrorCode PCGASMDestroySubdomains(PetscInt n, IS *iis[], IS *ois[])
1530: {
1531: PetscFunctionBegin;
1532: if (n <= 0) PetscFunctionReturn(PETSC_SUCCESS);
1533: if (ois) {
1534: PetscAssertPointer(ois, 3);
1535: if (*ois) {
1536: PetscAssertPointer(*ois, 3);
1537: for (PetscInt i = 0; i < n; i++) PetscCall(ISDestroy(&(*ois)[i]));
1538: PetscCall(PetscFree(*ois));
1539: }
1540: }
1541: if (iis) {
1542: PetscAssertPointer(iis, 2);
1543: if (*iis) {
1544: PetscAssertPointer(*iis, 2);
1545: for (PetscInt i = 0; i < n; i++) PetscCall(ISDestroy(&(*iis)[i]));
1546: PetscCall(PetscFree(*iis));
1547: }
1548: }
1549: PetscFunctionReturn(PETSC_SUCCESS);
1550: }
1552: #define PCGASMLocalSubdomainBounds2D(M, N, xleft, ylow, xright, yhigh, first, last, xleft_loc, ylow_loc, xright_loc, yhigh_loc, n) \
1553: do { \
1554: PetscInt first_row = first / M, last_row = last / M + 1; \
1555: /* \
1556: Compute ylow_loc and yhigh_loc so that (ylow_loc,xleft) and (yhigh_loc,xright) are the corners \
1557: of the bounding box of the intersection of the subdomain with the local ownership range (local \
1558: subdomain). \
1559: Also compute xleft_loc and xright_loc as the lower and upper bounds on the first and last rows \
1560: of the intersection. \
1561: */ \
1562: /* ylow_loc is the grid row containing the first element of the local sumbdomain */ \
1563: *ylow_loc = PetscMax(first_row, ylow); \
1564: /* xleft_loc is the offset of first element of the local subdomain within its grid row (might actually be outside the local subdomain) */ \
1565: *xleft_loc = *ylow_loc == first_row ? PetscMax(first % M, xleft) : xleft; \
1566: /* yhigh_loc is the grid row above the last local subdomain element */ \
1567: *yhigh_loc = PetscMin(last_row, yhigh); \
1568: /* xright is the offset of the end of the local subdomain within its grid row (might actually be outside the local subdomain) */ \
1569: *xright_loc = *yhigh_loc == last_row ? PetscMin(xright, last % M) : xright; \
1570: /* Now compute the size of the local subdomain n. */ \
1571: *n = 0; \
1572: if (*ylow_loc < *yhigh_loc) { \
1573: PetscInt width = xright - xleft; \
1574: *n += width * (*yhigh_loc - *ylow_loc - 1); \
1575: *n += PetscMin(PetscMax(*xright_loc - xleft, 0), width); \
1576: *n -= PetscMin(PetscMax(*xleft_loc - xleft, 0), width); \
1577: } \
1578: } while (0)
1580: /*@C
1581: PCGASMCreateSubdomains2D - Creates the index sets for the `PCGASM` overlapping Schwarz
1582: preconditioner for a two-dimensional problem on a regular grid.
1584: Collective
1586: Input Parameters:
1587: + pc - the preconditioner context
1588: . M - the global number of grid points in the x direction
1589: . N - the global number of grid points in the y direction
1590: . Mdomains - the global number of subdomains in the x direction
1591: . Ndomains - the global number of subdomains in the y direction
1592: . dof - degrees of freedom per node
1593: - overlap - overlap in mesh lines
1595: Output Parameters:
1596: + nsub - the number of local subdomains created
1597: . iis - array of index sets defining inner (nonoverlapping) subdomains
1598: - ois - array of index sets defining outer (overlapping, if overlap > 0) subdomains
1600: Level: advanced
1602: Note:
1603: Use `PCGASMDestroySubdomains()` to free the index sets and the arrays
1605: .seealso: [](ch_ksp), `PCGASM`, `PCGASMSetSubdomains()`, `PCGASMGetSubKSP()`, `PCGASMSetOverlap()`, `PCASMCreateSubdomains2D()`,
1606: `PCGASMDestroySubdomains()`
1607: @*/
1608: PetscErrorCode PCGASMCreateSubdomains2D(PC pc, PetscInt M, PetscInt N, PetscInt Mdomains, PetscInt Ndomains, PetscInt dof, PetscInt overlap, PetscInt *nsub, IS *iis[], IS *ois[])
1609: {
1610: PetscMPIInt size, rank;
1611: PetscInt maxheight, maxwidth;
1612: PetscInt xstart, xleft, xright, xleft_loc, xright_loc;
1613: PetscInt ystart, ylow, yhigh, ylow_loc, yhigh_loc;
1614: PetscInt x[2][2], y[2][2], n[2];
1615: PetscInt first, last;
1616: PetscInt nidx, *idx;
1617: PetscInt ii, jj, s, q, d;
1618: PetscInt k, kk;
1619: PetscMPIInt color;
1620: MPI_Comm comm, subcomm;
1621: IS **xis = NULL, **is = ois, **is_local = iis;
1623: PetscFunctionBegin;
1624: PetscCall(PetscObjectGetComm((PetscObject)pc, &comm));
1625: PetscCallMPI(MPI_Comm_size(comm, &size));
1626: PetscCallMPI(MPI_Comm_rank(comm, &rank));
1627: PetscCall(MatGetOwnershipRange(pc->pmat, &first, &last));
1628: PetscCheck((first % dof) == 0 && (last % dof) == 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE,
1629: "Matrix row partitioning unsuitable for domain decomposition: local row range (%" PetscInt_FMT ",%" PetscInt_FMT ") "
1630: "does not respect the number of degrees of freedom per grid point %" PetscInt_FMT,
1631: first, last, dof);
1633: /* Determine the number of domains with nonzero intersections with the local ownership range. */
1634: s = 0;
1635: ystart = 0;
1636: for (PetscInt j = 0; j < Ndomains; ++j) {
1637: maxheight = N / Ndomains + ((N % Ndomains) > j); /* Maximal height of subdomain */
1638: 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);
1639: /* Vertical domain limits with an overlap. */
1640: ylow = PetscMax(ystart - overlap, 0);
1641: yhigh = PetscMin(ystart + maxheight + overlap, N);
1642: xstart = 0;
1643: for (PetscInt i = 0; i < Mdomains; ++i) {
1644: maxwidth = M / Mdomains + ((M % Mdomains) > i); /* Maximal width of subdomain */
1645: 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);
1646: /* Horizontal domain limits with an overlap. */
1647: xleft = PetscMax(xstart - overlap, 0);
1648: xright = PetscMin(xstart + maxwidth + overlap, M);
1649: /*
1650: Determine whether this subdomain intersects this rank's ownership range of pc->pmat.
1651: */
1652: PCGASMLocalSubdomainBounds2D(M, N, xleft, ylow, xright, yhigh, first, last, (&xleft_loc), (&ylow_loc), (&xright_loc), (&yhigh_loc), (&nidx));
1653: if (nidx) ++s;
1654: xstart += maxwidth;
1655: } /* for (PetscInt i = 0; i < Mdomains; ++i) */
1656: ystart += maxheight;
1657: } /* for (PetscInt j = 0; j < Ndomains; ++j) */
1659: /* Now we can allocate the necessary number of ISs. */
1660: *nsub = s;
1661: PetscCall(PetscMalloc1(*nsub, is));
1662: PetscCall(PetscMalloc1(*nsub, is_local));
1663: s = 0;
1664: ystart = 0;
1665: for (PetscInt j = 0; j < Ndomains; ++j) {
1666: maxheight = N / Ndomains + ((N % Ndomains) > j); /* Maximal height of subdomain */
1667: 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);
1668: /* Vertical domain limits with an overlap. */
1669: y[0][0] = PetscMax(ystart - overlap, 0);
1670: y[0][1] = PetscMin(ystart + maxheight + overlap, N);
1671: /* Vertical domain limits without an overlap. */
1672: y[1][0] = ystart;
1673: y[1][1] = PetscMin(ystart + maxheight, N);
1674: xstart = 0;
1675: for (PetscInt i = 0; i < Mdomains; ++i) {
1676: maxwidth = M / Mdomains + ((M % Mdomains) > i); /* Maximal width of subdomain */
1677: 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);
1678: /* Horizontal domain limits with an overlap. */
1679: x[0][0] = PetscMax(xstart - overlap, 0);
1680: x[0][1] = PetscMin(xstart + maxwidth + overlap, M);
1681: /* Horizontal domain limits without an overlap. */
1682: x[1][0] = xstart;
1683: x[1][1] = PetscMin(xstart + maxwidth, M);
1684: /*
1685: Determine whether this domain intersects this rank's ownership range of pc->pmat.
1686: Do this twice: first for the domains with overlaps, and once without.
1687: During the first pass create the subcommunicators, and use them on the second pass as well.
1688: */
1689: for (q = 0; q < 2; ++q) {
1690: PetscBool split = PETSC_FALSE;
1691: /*
1692: domain limits, (xleft, xright) and (ylow, yheigh) are adjusted
1693: according to whether the domain with an overlap or without is considered.
1694: */
1695: xleft = x[q][0];
1696: xright = x[q][1];
1697: ylow = y[q][0];
1698: yhigh = y[q][1];
1699: PCGASMLocalSubdomainBounds2D(M, N, xleft, ylow, xright, yhigh, first, last, (&xleft_loc), (&ylow_loc), (&xright_loc), (&yhigh_loc), (&nidx));
1700: nidx *= dof;
1701: n[q] = nidx;
1702: /*
1703: Based on the counted number of indices in the local domain *with an overlap*,
1704: construct a subcommunicator of all the MPI ranks supporting this domain.
1705: Observe that a domain with an overlap might have nontrivial local support,
1706: while the domain without an overlap might not. Hence, the decision to participate
1707: in the subcommunicator must be based on the domain with an overlap.
1708: */
1709: if (q == 0) {
1710: if (nidx) color = 1;
1711: else color = MPI_UNDEFINED;
1712: PetscCallMPI(MPI_Comm_split(comm, color, rank, &subcomm));
1713: split = PETSC_TRUE;
1714: }
1715: /*
1716: Proceed only if the number of local indices *with an overlap* is nonzero.
1717: */
1718: if (n[0]) {
1719: if (q == 0) xis = is;
1720: if (q == 1) {
1721: /*
1722: The IS for the no-overlap subdomain shares a communicator with the overlapping domain.
1723: Moreover, if the overlap is zero, the two ISs are identical.
1724: */
1725: if (overlap == 0) {
1726: (*is_local)[s] = (*is)[s];
1727: PetscCall(PetscObjectReference((PetscObject)(*is)[s]));
1728: continue;
1729: } else {
1730: xis = is_local;
1731: subcomm = ((PetscObject)(*is)[s])->comm;
1732: }
1733: } /* if (q == 1) */
1734: idx = NULL;
1735: PetscCall(PetscMalloc1(nidx, &idx));
1736: if (nidx) {
1737: k = 0;
1738: for (jj = ylow_loc; jj < yhigh_loc; ++jj) {
1739: PetscInt x0 = (jj == ylow_loc) ? xleft_loc : xleft;
1740: PetscInt x1 = (jj == yhigh_loc - 1) ? xright_loc : xright;
1741: kk = dof * (M * jj + x0);
1742: for (ii = x0; ii < x1; ++ii) {
1743: for (d = 0; d < dof; ++d) idx[k++] = kk++;
1744: }
1745: }
1746: }
1747: PetscCall(ISCreateGeneral(subcomm, nidx, idx, PETSC_OWN_POINTER, (*xis) + s));
1748: if (split) PetscCallMPI(MPI_Comm_free(&subcomm));
1749: } /* if (n[0]) */
1750: } /* for (q = 0; q < 2; ++q) */
1751: if (n[0]) ++s;
1752: xstart += maxwidth;
1753: } /* for (PetscInt i = 0; i < Mdomains; ++i) */
1754: ystart += maxheight;
1755: } /* for (PetscInt j = 0; j < Ndomains; ++j) */
1756: PetscFunctionReturn(PETSC_SUCCESS);
1757: }
1759: /*@C
1760: PCGASMGetSubdomains - Gets the subdomains supported on this MPI process
1761: for the `PCGASM` additive Schwarz preconditioner.
1763: Not Collective
1765: Input Parameter:
1766: . pc - the preconditioner context
1768: Output Parameters:
1769: + n - the number of subdomains for this MPI process (default value = 1)
1770: . iis - the index sets that define the inner subdomains (without overlap) supported on this process (can be `NULL`)
1771: - ois - the index sets that define the outer subdomains (with overlap) supported on this process (can be `NULL`)
1773: Level: advanced
1775: Notes:
1776: The user is responsible for destroying the `IS`s and freeing the returned arrays, this can be done with
1777: `PCGASMDestroySubdomains()`
1779: The `IS` numbering is in the parallel, global numbering of the vector.
1781: .seealso: [](ch_ksp), `PCGASM`, `PCGASMSetOverlap()`, `PCGASMGetSubKSP()`, `PCGASMCreateSubdomains2D()`,
1782: `PCGASMSetSubdomains()`, `PCGASMGetSubmatrices()`, `PCGASMDestroySubdomains()`
1783: @*/
1784: PetscErrorCode PCGASMGetSubdomains(PC pc, PetscInt *n, IS *iis[], IS *ois[])
1785: {
1786: PC_GASM *osm;
1787: PetscBool match;
1789: PetscFunctionBegin;
1791: PetscCall(PetscObjectTypeCompare((PetscObject)pc, PCGASM, &match));
1792: PetscCheck(match, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONG, "Incorrect object type: expected %s, got %s instead", PCGASM, ((PetscObject)pc)->type_name);
1793: osm = (PC_GASM *)pc->data;
1794: if (n) *n = osm->n;
1795: if (iis) PetscCall(PetscMalloc1(osm->n, iis));
1796: if (ois) PetscCall(PetscMalloc1(osm->n, ois));
1797: if (iis || ois) {
1798: for (PetscInt i = 0; i < osm->n; ++i) {
1799: if (iis) (*iis)[i] = osm->iis[i];
1800: if (ois) (*ois)[i] = osm->ois[i];
1801: }
1802: }
1803: PetscFunctionReturn(PETSC_SUCCESS);
1804: }
1806: /*@C
1807: PCGASMGetSubmatrices - Gets the local submatrices (for this MPI process
1808: only) for the `PCGASM` additive Schwarz preconditioner.
1810: Not Collective
1812: Input Parameter:
1813: . pc - the preconditioner context
1815: Output Parameters:
1816: + n - the number of matrices for this MPI process (default value = 1)
1817: - mat - the matrices
1819: Level: advanced
1821: Note:
1822: Matrices returned by this routine have the same communicators as the index sets (`IS`)
1823: used to define subdomains in `PCGASMSetSubdomains()`
1825: .seealso: [](ch_ksp), `PCGASM`, `PCGASMSetOverlap()`, `PCGASMGetSubKSP()`,
1826: `PCGASMCreateSubdomains2D()`, `PCGASMSetSubdomains()`, `PCGASMGetSubdomains()`
1827: @*/
1828: PetscErrorCode PCGASMGetSubmatrices(PC pc, PetscInt *n, Mat *mat[])
1829: {
1830: PC_GASM *osm;
1831: PetscBool match;
1833: PetscFunctionBegin;
1835: PetscAssertPointer(n, 2);
1836: if (mat) PetscAssertPointer(mat, 3);
1837: PetscCheck(pc->setupcalled, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONGSTATE, "Must call after KSPSetUp() or PCSetUp().");
1838: PetscCall(PetscObjectTypeCompare((PetscObject)pc, PCGASM, &match));
1839: PetscCheck(match, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONG, "Expected %s, got %s instead", PCGASM, ((PetscObject)pc)->type_name);
1840: osm = (PC_GASM *)pc->data;
1841: if (n) *n = osm->n;
1842: if (mat) *mat = osm->pmat;
1843: PetscFunctionReturn(PETSC_SUCCESS);
1844: }
1846: /*@
1847: PCGASMSetUseDMSubdomains - Indicates whether to use `DMCreateDomainDecomposition()` to define the subdomains, whenever possible for `PCGASM`
1849: Logically Collective
1851: Input Parameters:
1852: + pc - the preconditioner
1853: - flg - boolean indicating whether to use subdomains defined by the `DM`
1855: Options Database Key:
1856: + -pc_gasm_dm_subdomains - configure subdomains
1857: . -pc_gasm_overlap - set overlap
1858: - -pc_gasm_total_subdomains - set number of subdomains
1860: Level: intermediate
1862: Note:
1863: `PCGASMSetSubdomains()`, `PCGASMSetTotalSubdomains()` or `PCGASMSetOverlap()` take precedence over `PCGASMSetUseDMSubdomains()`,
1864: so setting `PCGASMSetSubdomains()` with nontrivial subdomain ISs or any of `PCGASMSetTotalSubdomains()` and `PCGASMSetOverlap()`
1865: automatically turns the latter off.
1867: .seealso: [](ch_ksp), `PCGASM`, `PCGASMGetUseDMSubdomains()`, `PCGASMSetSubdomains()`, `PCGASMSetOverlap()`,
1868: `PCGASMCreateSubdomains2D()`
1869: @*/
1870: PetscErrorCode PCGASMSetUseDMSubdomains(PC pc, PetscBool flg)
1871: {
1872: PC_GASM *osm = (PC_GASM *)pc->data;
1873: PetscBool match;
1875: PetscFunctionBegin;
1878: PetscCheck(!pc->setupcalled, ((PetscObject)pc)->comm, PETSC_ERR_ARG_WRONGSTATE, "Not for a setup PC.");
1879: PetscCall(PetscObjectTypeCompare((PetscObject)pc, PCGASM, &match));
1880: if (match && !osm->user_subdomains && osm->N == PETSC_DETERMINE && osm->overlap < 0) osm->dm_subdomains = flg;
1881: PetscFunctionReturn(PETSC_SUCCESS);
1882: }
1884: /*@
1885: PCGASMGetUseDMSubdomains - Returns flag indicating whether to use `DMCreateDomainDecomposition()` to define the subdomains, whenever possible with `PCGASM`
1887: Not Collective
1889: Input Parameter:
1890: . pc - the preconditioner
1892: Output Parameter:
1893: . flg - boolean indicating whether to use subdomains defined by the `DM`
1895: Level: intermediate
1897: .seealso: [](ch_ksp), `PCGASM`, `PCGASMSetUseDMSubdomains()`, `PCGASMSetOverlap()`,
1898: `PCGASMCreateSubdomains2D()`
1899: @*/
1900: PetscErrorCode PCGASMGetUseDMSubdomains(PC pc, PetscBool *flg)
1901: {
1902: PC_GASM *osm = (PC_GASM *)pc->data;
1903: PetscBool match;
1905: PetscFunctionBegin;
1907: PetscAssertPointer(flg, 2);
1908: PetscCall(PetscObjectTypeCompare((PetscObject)pc, PCGASM, &match));
1909: if (match) {
1910: if (flg) *flg = osm->dm_subdomains;
1911: }
1912: PetscFunctionReturn(PETSC_SUCCESS);
1913: }