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 j, 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 (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 (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 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 */
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, &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: }
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: 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: }
381: /* Now the subdomains are defined. Determine their global and max local numbers, if necessary. */
382: if (osm->nmax == PETSC_DETERMINE) {
383: PetscMPIInt inwork, outwork;
384: /* determine global number of subdomains and the max number of local subdomains */
385: inwork = osm->n;
386: PetscCall(MPIU_Allreduce(&inwork, &outwork, 1, MPI_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: }
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));
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));
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));
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));
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: }
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: }
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));
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: }
590: static PetscErrorCode PCSetUpOnBlocks_GASM(PC pc)
591: {
592: PC_GASM *osm = (PC_GASM *)pc->data;
593: PetscInt i;
595: PetscFunctionBegin;
596: for (i = 0; i < osm->n; i++) PetscCall(KSPSetUp(osm->ksp[i]));
597: PetscFunctionReturn(PETSC_SUCCESS);
598: }
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;
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: }
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;
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: }
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;
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).
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: }
796: static PetscErrorCode PCReset_GASM(PC pc)
797: {
798: PC_GASM *osm = (PC_GASM *)pc->data;
799: PetscInt i;
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));
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: }
842: static PetscErrorCode PCDestroy_GASM(PC pc)
843: {
844: PC_GASM *osm = (PC_GASM *)pc->data;
845: PetscInt i;
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: }
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;
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: }
891: /*@
892: PCGASMSetTotalSubdomains - sets the total number of subdomains to use across the communicator for `PCGASM`
894: Logically Collective
896: Input Parameters:
897: + pc - the preconditioner
898: - N - total number of subdomains
900: Level: beginner
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;
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().");
914: PetscCall(PCGASMDestroySubdomains(osm->n, &osm->iis, &osm->ois));
915: osm->ois = osm->iis = NULL;
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: }
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;
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().");
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: }
990: static PetscErrorCode PCGASMSetOverlap_GASM(PC pc, PetscInt ovl)
991: {
992: PC_GASM *osm = (PC_GASM *)pc->data;
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: }
1001: static PetscErrorCode PCGASMSetType_GASM(PC pc, PCGASMType type)
1002: {
1003: PC_GASM *osm = (PC_GASM *)pc->data;
1005: PetscFunctionBegin;
1006: osm->type = type;
1007: osm->type_set = PETSC_TRUE;
1008: PetscFunctionReturn(PETSC_SUCCESS);
1009: }
1011: static PetscErrorCode PCGASMSetSortIndices_GASM(PC pc, PetscBool doSort)
1012: {
1013: PC_GASM *osm = (PC_GASM *)pc->data;
1015: PetscFunctionBegin;
1016: osm->sort_indices = doSort;
1017: PetscFunctionReturn(PETSC_SUCCESS);
1018: }
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;
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");
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() */
1045: /*@
1046: PCGASMSetSubdomains - Sets the subdomains for this MPI process
1047: for the additive Schwarz preconditioner with multiple MPI processes per subdomain, `PCGASM`
1049: Collective
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.
1059: Level: advanced
1061: Notes:
1062: The `IS` indices use the parallel, global numbering of the vector entries.
1064: Inner subdomains are those where the correction is applied.
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).
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.
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.
1077: By default the `PGASM` preconditioner uses 1 (local) subdomain per MPI process.
1079: The `iis` and `ois` arrays may be freed after this call using `PCGASMDestroySubdomains()`
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;
1088: PetscFunctionBegin;
1090: PetscTryMethod(pc, "PCGASMSetSubdomains_C", (PC, PetscInt, IS[], IS[]), (pc, n, iis, ois));
1091: osm->dm_subdomains = PETSC_FALSE;
1092: PetscFunctionReturn(PETSC_SUCCESS);
1093: }
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.
1100: Logically Collective
1102: Input Parameters:
1103: + pc - the preconditioner context
1104: - ovl - the amount of overlap between subdomains (ovl >= 0, default value = 0)
1106: Options Database Key:
1107: . -pc_gasm_overlap <overlap> - Sets overlap
1109: Level: intermediate
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>).
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.
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.
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;
1134: PetscFunctionBegin;
1137: PetscTryMethod(pc, "PCGASMSetOverlap_C", (PC, PetscInt), (pc, ovl));
1138: osm->dm_subdomains = PETSC_FALSE;
1139: PetscFunctionReturn(PETSC_SUCCESS);
1140: }
1142: /*@
1143: PCGASMSetType - Sets the type of restriction and interpolation used
1144: for local problems in the `PCGASM` additive Schwarz method.
1146: Logically Collective
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
1158: Options Database Key:
1159: . -pc_gasm_type [basic,restrict,interpolate,none] - Sets `PCGASM` type
1161: Level: intermediate
1163: .seealso: [](ch_ksp), `PCGASM`, `PCGASMSetSubdomains()`, `PCGASMGetSubKSP()`,
1164: `PCGASMCreateSubdomains2D()`, `PCASM`, `PCASMSetType()`
1165: @*/
1166: PetscErrorCode PCGASMSetType(PC pc, PCGASMType type)
1167: {
1168: PetscFunctionBegin;
1171: PetscTryMethod(pc, "PCGASMSetType_C", (PC, PCGASMType), (pc, type));
1172: PetscFunctionReturn(PETSC_SUCCESS);
1173: }
1175: /*@
1176: PCGASMSetSortIndices - Determines whether subdomain indices are sorted.
1178: Logically Collective
1180: Input Parameters:
1181: + pc - the preconditioner context
1182: - doSort - sort the subdomain indices
1184: Level: intermediate
1186: .seealso: [](ch_ksp), `PCGASM`, `PCGASMSetSubdomains()`, `PCGASMGetSubKSP()`,
1187: `PCGASMCreateSubdomains2D()`
1188: @*/
1189: PetscErrorCode PCGASMSetSortIndices(PC pc, PetscBool doSort)
1190: {
1191: PetscFunctionBegin;
1194: PetscTryMethod(pc, "PCGASMSetSortIndices_C", (PC, PetscBool), (pc, doSort));
1195: PetscFunctionReturn(PETSC_SUCCESS);
1196: }
1198: /*@C
1199: PCGASMGetSubKSP - Gets the local `KSP` contexts for all subdomains on this MPI process.
1201: Collective iff first_local is requested
1203: Input Parameter:
1204: . pc - the preconditioner context
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
1211: Level: advanced
1213: Note:
1214: After `PCGASMGetSubKSP()` the array of `KSP`es is not to be freed
1216: Currently for some matrix implementations only 1 block per MPI process
1217: is supported.
1219: You must call `KSPSetUp()` before calling `PCGASMGetSubKSP()`.
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;
1228: PetscUseMethod(pc, "PCGASMGetSubKSP_C", (PC, PetscInt *, PetscInt *, KSP **), (pc, n_local, first_local, ksp));
1229: PetscFunctionReturn(PETSC_SUCCESS);
1230: }
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
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`
1243: Level: beginner
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`
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()`)
1253: See {cite}`dryja1987additive` and {cite}`1sbg` for details on additive Schwarz algorithms
1255: .seealso: [](ch_ksp), `PCCreate()`, `PCSetType()`, `PCType`, `PC`, `PCASM`, `PCGASMType`, `PCGASMSetType()`,
1256: `PCBJACOBI`, `PCGASMGetSubKSP()`, `PCGASMSetSubdomains()`,
1257: `PCSetModifySubMatrices()`, `PCGASMSetOverlap()`, `PCGASMSetType()`
1258: M*/
1260: PETSC_EXTERN PetscErrorCode PCCreate_GASM(PC pc)
1261: {
1262: PC_GASM *osm;
1264: PetscFunctionBegin;
1265: PetscCall(PetscNew(&osm));
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;
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;
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: }
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;
1322: PetscFunctionBegin;
1323: PetscCheck(nloc >= 1, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "number of local subdomains must > 0, got nloc = %" PetscInt_FMT, nloc);
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);
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 */
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: }
1408: } else {
1409: /* Partitioning by adjacency of diagonal block */
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;
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: }
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: }
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: }
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.
1465: Collective
1467: Input Parameters:
1468: + A - The global matrix operator
1469: - N - the number of global subdomains requested
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)
1475: Level: advanced
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.
1484: Use `PCGASMDestroySubdomains()` to free the array and the list of index sets.
1486: .seealso: [](ch_ksp), `PCGASM`, `PCGASMSetSubdomains()`, `PCGASMDestroySubdomains()`
1487: @*/
1488: PetscErrorCode PCGASMCreateSubdomains(Mat A, PetscInt N, PetscInt *n, IS *iis[])
1489: {
1490: PetscMPIInt size;
1492: PetscFunctionBegin;
1494: PetscAssertPointer(iis, 4);
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: }
1507: /*@C
1508: PCGASMDestroySubdomains - Destroys the index sets created with
1509: `PCGASMCreateSubdomains()` or `PCGASMCreateSubdomains2D()`. Should be
1510: called after setting subdomains with `PCGASMSetSubdomains()`.
1512: Collective
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`
1519: Level: intermediate
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`.
1526: Fortran Note:
1527: The arrays are not freed, only the `IS` within the arrays are destroyed
1529: .seealso: [](ch_ksp), `PCGASM`, `PCGASMCreateSubdomains()`, `PCGASMSetSubdomains()`
1530: @*/
1531: PetscErrorCode PCGASMDestroySubdomains(PetscInt n, IS *iis[], IS *ois[])
1532: {
1533: PetscInt i;
1535: PetscFunctionBegin;
1536: if (n <= 0) PetscFunctionReturn(PETSC_SUCCESS);
1537: if (ois) {
1538: PetscAssertPointer(ois, 3);
1539: if (*ois) {
1540: PetscAssertPointer(*ois, 3);
1541: for (i = 0; i < n; i++) PetscCall(ISDestroy(&(*ois)[i]));
1542: PetscCall(PetscFree(*ois));
1543: }
1544: }
1545: if (iis) {
1546: PetscAssertPointer(iis, 2);
1547: if (*iis) {
1548: PetscAssertPointer(*iis, 2);
1549: for (i = 0; i < n; i++) PetscCall(ISDestroy(&(*iis)[i]));
1550: PetscCall(PetscFree(*iis));
1551: }
1552: }
1553: PetscFunctionReturn(PETSC_SUCCESS);
1554: }
1556: #define PCGASMLocalSubdomainBounds2D(M, N, xleft, ylow, xright, yhigh, first, last, xleft_loc, ylow_loc, xright_loc, yhigh_loc, n) \
1557: do { \
1558: PetscInt first_row = first / M, last_row = last / M + 1; \
1559: /* \
1560: Compute ylow_loc and yhigh_loc so that (ylow_loc,xleft) and (yhigh_loc,xright) are the corners \
1561: of the bounding box of the intersection of the subdomain with the local ownership range (local \
1562: subdomain). \
1563: Also compute xleft_loc and xright_loc as the lower and upper bounds on the first and last rows \
1564: of the intersection. \
1565: */ \
1566: /* ylow_loc is the grid row containing the first element of the local sumbdomain */ \
1567: *ylow_loc = PetscMax(first_row, ylow); \
1568: /* xleft_loc is the offset of first element of the local subdomain within its grid row (might actually be outside the local subdomain) */ \
1569: *xleft_loc = *ylow_loc == first_row ? PetscMax(first % M, xleft) : xleft; \
1570: /* yhigh_loc is the grid row above the last local subdomain element */ \
1571: *yhigh_loc = PetscMin(last_row, yhigh); \
1572: /* xright is the offset of the end of the local subdomain within its grid row (might actually be outside the local subdomain) */ \
1573: *xright_loc = *yhigh_loc == last_row ? PetscMin(xright, last % M) : xright; \
1574: /* Now compute the size of the local subdomain n. */ \
1575: *n = 0; \
1576: if (*ylow_loc < *yhigh_loc) { \
1577: PetscInt width = xright - xleft; \
1578: *n += width * (*yhigh_loc - *ylow_loc - 1); \
1579: *n += PetscMin(PetscMax(*xright_loc - xleft, 0), width); \
1580: *n -= PetscMin(PetscMax(*xleft_loc - xleft, 0), width); \
1581: } \
1582: } while (0)
1584: /*@C
1585: PCGASMCreateSubdomains2D - Creates the index sets for the `PCGASM` overlapping Schwarz
1586: preconditioner for a two-dimensional problem on a regular grid.
1588: Collective
1590: Input Parameters:
1591: + pc - the preconditioner context
1592: . M - the global number of grid points in the x direction
1593: . N - the global number of grid points in the y direction
1594: . Mdomains - the global number of subdomains in the x direction
1595: . Ndomains - the global number of subdomains in the y direction
1596: . dof - degrees of freedom per node
1597: - overlap - overlap in mesh lines
1599: Output Parameters:
1600: + nsub - the number of local subdomains created
1601: . iis - array of index sets defining inner (nonoverlapping) subdomains
1602: - ois - array of index sets defining outer (overlapping, if overlap > 0) subdomains
1604: Level: advanced
1606: Note:
1607: Use `PCGASMDestroySubdomains()` to free the index sets and the arrays
1609: Fortran Notes:
1610: The `IS` must be declared as an array of length long enough to hold `Nsub` entries
1612: .seealso: [](ch_ksp), `PCGASM`, `PCGASMSetSubdomains()`, `PCGASMGetSubKSP()`, `PCGASMSetOverlap()`, `PCASMCreateSubdomains2D()`,
1613: `PCGASMDestroySubdomains()`
1614: @*/
1615: PetscErrorCode PCGASMCreateSubdomains2D(PC pc, PetscInt M, PetscInt N, PetscInt Mdomains, PetscInt Ndomains, PetscInt dof, PetscInt overlap, PetscInt *nsub, IS *iis[], IS *ois[])
1616: {
1617: PetscMPIInt size, rank;
1618: PetscInt i, j;
1619: PetscInt maxheight, maxwidth;
1620: PetscInt xstart, xleft, xright, xleft_loc, xright_loc;
1621: PetscInt ystart, ylow, yhigh, ylow_loc, yhigh_loc;
1622: PetscInt x[2][2], y[2][2], n[2];
1623: PetscInt first, last;
1624: PetscInt nidx, *idx;
1625: PetscInt ii, jj, s, q, d;
1626: PetscInt k, kk;
1627: PetscMPIInt color;
1628: MPI_Comm comm, subcomm;
1629: IS **xis = NULL, **is = ois, **is_local = iis;
1631: PetscFunctionBegin;
1632: PetscCall(PetscObjectGetComm((PetscObject)pc, &comm));
1633: PetscCallMPI(MPI_Comm_size(comm, &size));
1634: PetscCallMPI(MPI_Comm_rank(comm, &rank));
1635: PetscCall(MatGetOwnershipRange(pc->pmat, &first, &last));
1636: PetscCheck((first % dof) == 0 && (last % dof) == 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE,
1637: "Matrix row partitioning unsuitable for domain decomposition: local row range (%" PetscInt_FMT ",%" PetscInt_FMT ") "
1638: "does not respect the number of degrees of freedom per grid point %" PetscInt_FMT,
1639: first, last, dof);
1641: /* Determine the number of domains with nonzero intersections with the local ownership range. */
1642: s = 0;
1643: ystart = 0;
1644: for (j = 0; j < Ndomains; ++j) {
1645: maxheight = N / Ndomains + ((N % Ndomains) > j); /* Maximal height of subdomain */
1646: 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);
1647: /* Vertical domain limits with an overlap. */
1648: ylow = PetscMax(ystart - overlap, 0);
1649: yhigh = PetscMin(ystart + maxheight + overlap, N);
1650: xstart = 0;
1651: for (i = 0; i < Mdomains; ++i) {
1652: maxwidth = M / Mdomains + ((M % Mdomains) > i); /* Maximal width of subdomain */
1653: 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);
1654: /* Horizontal domain limits with an overlap. */
1655: xleft = PetscMax(xstart - overlap, 0);
1656: xright = PetscMin(xstart + maxwidth + overlap, M);
1657: /*
1658: Determine whether this subdomain intersects this rank's ownership range of pc->pmat.
1659: */
1660: PCGASMLocalSubdomainBounds2D(M, N, xleft, ylow, xright, yhigh, first, last, (&xleft_loc), (&ylow_loc), (&xright_loc), (&yhigh_loc), (&nidx));
1661: if (nidx) ++s;
1662: xstart += maxwidth;
1663: } /* for (i = 0; i < Mdomains; ++i) */
1664: ystart += maxheight;
1665: } /* for (j = 0; j < Ndomains; ++j) */
1667: /* Now we can allocate the necessary number of ISs. */
1668: *nsub = s;
1669: PetscCall(PetscMalloc1(*nsub, is));
1670: PetscCall(PetscMalloc1(*nsub, is_local));
1671: s = 0;
1672: ystart = 0;
1673: for (j = 0; j < Ndomains; ++j) {
1674: maxheight = N / Ndomains + ((N % Ndomains) > j); /* Maximal height of subdomain */
1675: 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);
1676: /* Vertical domain limits with an overlap. */
1677: y[0][0] = PetscMax(ystart - overlap, 0);
1678: y[0][1] = PetscMin(ystart + maxheight + overlap, N);
1679: /* Vertical domain limits without an overlap. */
1680: y[1][0] = ystart;
1681: y[1][1] = PetscMin(ystart + maxheight, N);
1682: xstart = 0;
1683: for (i = 0; i < Mdomains; ++i) {
1684: maxwidth = M / Mdomains + ((M % Mdomains) > i); /* Maximal width of subdomain */
1685: 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);
1686: /* Horizontal domain limits with an overlap. */
1687: x[0][0] = PetscMax(xstart - overlap, 0);
1688: x[0][1] = PetscMin(xstart + maxwidth + overlap, M);
1689: /* Horizontal domain limits without an overlap. */
1690: x[1][0] = xstart;
1691: x[1][1] = PetscMin(xstart + maxwidth, M);
1692: /*
1693: Determine whether this domain intersects this rank's ownership range of pc->pmat.
1694: Do this twice: first for the domains with overlaps, and once without.
1695: During the first pass create the subcommunicators, and use them on the second pass as well.
1696: */
1697: for (q = 0; q < 2; ++q) {
1698: PetscBool split = PETSC_FALSE;
1699: /*
1700: domain limits, (xleft, xright) and (ylow, yheigh) are adjusted
1701: according to whether the domain with an overlap or without is considered.
1702: */
1703: xleft = x[q][0];
1704: xright = x[q][1];
1705: ylow = y[q][0];
1706: yhigh = y[q][1];
1707: PCGASMLocalSubdomainBounds2D(M, N, xleft, ylow, xright, yhigh, first, last, (&xleft_loc), (&ylow_loc), (&xright_loc), (&yhigh_loc), (&nidx));
1708: nidx *= dof;
1709: n[q] = nidx;
1710: /*
1711: Based on the counted number of indices in the local domain *with an overlap*,
1712: construct a subcommunicator of all the MPI ranks supporting this domain.
1713: Observe that a domain with an overlap might have nontrivial local support,
1714: while the domain without an overlap might not. Hence, the decision to participate
1715: in the subcommunicator must be based on the domain with an overlap.
1716: */
1717: if (q == 0) {
1718: if (nidx) color = 1;
1719: else color = MPI_UNDEFINED;
1720: PetscCallMPI(MPI_Comm_split(comm, color, rank, &subcomm));
1721: split = PETSC_TRUE;
1722: }
1723: /*
1724: Proceed only if the number of local indices *with an overlap* is nonzero.
1725: */
1726: if (n[0]) {
1727: if (q == 0) xis = is;
1728: if (q == 1) {
1729: /*
1730: The IS for the no-overlap subdomain shares a communicator with the overlapping domain.
1731: Moreover, if the overlap is zero, the two ISs are identical.
1732: */
1733: if (overlap == 0) {
1734: (*is_local)[s] = (*is)[s];
1735: PetscCall(PetscObjectReference((PetscObject)(*is)[s]));
1736: continue;
1737: } else {
1738: xis = is_local;
1739: subcomm = ((PetscObject)(*is)[s])->comm;
1740: }
1741: } /* if (q == 1) */
1742: idx = NULL;
1743: PetscCall(PetscMalloc1(nidx, &idx));
1744: if (nidx) {
1745: k = 0;
1746: for (jj = ylow_loc; jj < yhigh_loc; ++jj) {
1747: PetscInt x0 = (jj == ylow_loc) ? xleft_loc : xleft;
1748: PetscInt x1 = (jj == yhigh_loc - 1) ? xright_loc : xright;
1749: kk = dof * (M * jj + x0);
1750: for (ii = x0; ii < x1; ++ii) {
1751: for (d = 0; d < dof; ++d) idx[k++] = kk++;
1752: }
1753: }
1754: }
1755: PetscCall(ISCreateGeneral(subcomm, nidx, idx, PETSC_OWN_POINTER, (*xis) + s));
1756: if (split) PetscCallMPI(MPI_Comm_free(&subcomm));
1757: } /* if (n[0]) */
1758: } /* for (q = 0; q < 2; ++q) */
1759: if (n[0]) ++s;
1760: xstart += maxwidth;
1761: } /* for (i = 0; i < Mdomains; ++i) */
1762: ystart += maxheight;
1763: } /* for (j = 0; j < Ndomains; ++j) */
1764: PetscFunctionReturn(PETSC_SUCCESS);
1765: }
1767: /*@C
1768: PCGASMGetSubdomains - Gets the subdomains supported on this MPI process
1769: for the `PCGASM` additive Schwarz preconditioner.
1771: Not Collective
1773: Input Parameter:
1774: . pc - the preconditioner context
1776: Output Parameters:
1777: + n - the number of subdomains for this MPI process (default value = 1)
1778: . iis - the index sets that define the inner subdomains (without overlap) supported on this process (can be `NULL`)
1779: - ois - the index sets that define the outer subdomains (with overlap) supported on this process (can be `NULL`)
1781: Level: advanced
1783: Notes:
1784: The user is responsible for destroying the `IS`s and freeing the returned arrays, this can be done with
1785: `PCGASMDestroySubdomains()`
1787: The `IS` numbering is in the parallel, global numbering of the vector.
1789: .seealso: [](ch_ksp), `PCGASM`, `PCGASMSetOverlap()`, `PCGASMGetSubKSP()`, `PCGASMCreateSubdomains2D()`,
1790: `PCGASMSetSubdomains()`, `PCGASMGetSubmatrices()`, `PCGASMDestroySubdomains()`
1791: @*/
1792: PetscErrorCode PCGASMGetSubdomains(PC pc, PetscInt *n, IS *iis[], IS *ois[])
1793: {
1794: PC_GASM *osm;
1795: PetscBool match;
1796: PetscInt i;
1798: PetscFunctionBegin;
1800: PetscCall(PetscObjectTypeCompare((PetscObject)pc, PCGASM, &match));
1801: PetscCheck(match, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONG, "Incorrect object type: expected %s, got %s instead", PCGASM, ((PetscObject)pc)->type_name);
1802: osm = (PC_GASM *)pc->data;
1803: if (n) *n = osm->n;
1804: if (iis) PetscCall(PetscMalloc1(osm->n, iis));
1805: if (ois) PetscCall(PetscMalloc1(osm->n, ois));
1806: if (iis || ois) {
1807: for (i = 0; i < osm->n; ++i) {
1808: if (iis) (*iis)[i] = osm->iis[i];
1809: if (ois) (*ois)[i] = osm->ois[i];
1810: }
1811: }
1812: PetscFunctionReturn(PETSC_SUCCESS);
1813: }
1815: /*@C
1816: PCGASMGetSubmatrices - Gets the local submatrices (for this MPI process
1817: only) for the `PCGASM` additive Schwarz preconditioner.
1819: Not Collective
1821: Input Parameter:
1822: . pc - the preconditioner context
1824: Output Parameters:
1825: + n - the number of matrices for this MPI process (default value = 1)
1826: - mat - the matrices
1828: Level: advanced
1830: Note:
1831: Matrices returned by this routine have the same communicators as the index sets (`IS`)
1832: used to define subdomains in `PCGASMSetSubdomains()`
1834: .seealso: [](ch_ksp), `PCGASM`, `PCGASMSetOverlap()`, `PCGASMGetSubKSP()`,
1835: `PCGASMCreateSubdomains2D()`, `PCGASMSetSubdomains()`, `PCGASMGetSubdomains()`
1836: @*/
1837: PetscErrorCode PCGASMGetSubmatrices(PC pc, PetscInt *n, Mat *mat[])
1838: {
1839: PC_GASM *osm;
1840: PetscBool match;
1842: PetscFunctionBegin;
1844: PetscAssertPointer(n, 2);
1845: if (mat) PetscAssertPointer(mat, 3);
1846: PetscCheck(pc->setupcalled, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONGSTATE, "Must call after KSPSetUp() or PCSetUp().");
1847: PetscCall(PetscObjectTypeCompare((PetscObject)pc, PCGASM, &match));
1848: PetscCheck(match, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONG, "Expected %s, got %s instead", PCGASM, ((PetscObject)pc)->type_name);
1849: osm = (PC_GASM *)pc->data;
1850: if (n) *n = osm->n;
1851: if (mat) *mat = osm->pmat;
1852: PetscFunctionReturn(PETSC_SUCCESS);
1853: }
1855: /*@
1856: PCGASMSetUseDMSubdomains - Indicates whether to use `DMCreateDomainDecomposition()` to define the subdomains, whenever possible for `PCGASM`
1858: Logically Collective
1860: Input Parameters:
1861: + pc - the preconditioner
1862: - flg - boolean indicating whether to use subdomains defined by the `DM`
1864: Options Database Key:
1865: + -pc_gasm_dm_subdomains - configure subdomains
1866: . -pc_gasm_overlap - set overlap
1867: - -pc_gasm_total_subdomains - set number of subdomains
1869: Level: intermediate
1871: Note:
1872: `PCGASMSetSubdomains()`, `PCGASMSetTotalSubdomains()` or `PCGASMSetOverlap()` take precedence over `PCGASMSetUseDMSubdomains()`,
1873: so setting `PCGASMSetSubdomains()` with nontrivial subdomain ISs or any of `PCGASMSetTotalSubdomains()` and `PCGASMSetOverlap()`
1874: automatically turns the latter off.
1876: .seealso: [](ch_ksp), `PCGASM`, `PCGASMGetUseDMSubdomains()`, `PCGASMSetSubdomains()`, `PCGASMSetOverlap()`
1877: `PCGASMCreateSubdomains2D()`
1878: @*/
1879: PetscErrorCode PCGASMSetUseDMSubdomains(PC pc, PetscBool flg)
1880: {
1881: PC_GASM *osm = (PC_GASM *)pc->data;
1882: PetscBool match;
1884: PetscFunctionBegin;
1887: PetscCheck(!pc->setupcalled, ((PetscObject)pc)->comm, PETSC_ERR_ARG_WRONGSTATE, "Not for a setup PC.");
1888: PetscCall(PetscObjectTypeCompare((PetscObject)pc, PCGASM, &match));
1889: if (match) {
1890: if (!osm->user_subdomains && osm->N == PETSC_DETERMINE && osm->overlap < 0) osm->dm_subdomains = flg;
1891: }
1892: PetscFunctionReturn(PETSC_SUCCESS);
1893: }
1895: /*@
1896: PCGASMGetUseDMSubdomains - Returns flag indicating whether to use `DMCreateDomainDecomposition()` to define the subdomains, whenever possible with `PCGASM`
1898: Not Collective
1900: Input Parameter:
1901: . pc - the preconditioner
1903: Output Parameter:
1904: . flg - boolean indicating whether to use subdomains defined by the `DM`
1906: Level: intermediate
1908: .seealso: [](ch_ksp), `PCGASM`, `PCGASMSetUseDMSubdomains()`, `PCGASMSetOverlap()`
1909: `PCGASMCreateSubdomains2D()`
1910: @*/
1911: PetscErrorCode PCGASMGetUseDMSubdomains(PC pc, PetscBool *flg)
1912: {
1913: PC_GASM *osm = (PC_GASM *)pc->data;
1914: PetscBool match;
1916: PetscFunctionBegin;
1918: PetscAssertPointer(flg, 2);
1919: PetscCall(PetscObjectTypeCompare((PetscObject)pc, PCGASM, &match));
1920: if (match) {
1921: if (flg) *flg = osm->dm_subdomains;
1922: }
1923: PetscFunctionReturn(PETSC_SUCCESS);
1924: }