Actual source code: plexdistribute.c

  1: #include <petsc/private/dmpleximpl.h>
  2: #include <petsc/private/dmlabelimpl.h>

  4: /*@C
  5:   DMPlexSetAdjacencyUser - Define adjacency in the mesh using a user-provided callback

  7:   Input Parameters:
  8: + dm   - The DM object
  9: . user - The user callback, may be `NULL` (to clear the callback)
 10: - ctx  - context for callback evaluation, may be `NULL`

 12:   Level: advanced

 14:   Notes:
 15:   The caller of `DMPlexGetAdjacency()` may need to arrange that a large enough array is available for the adjacency.

 17:   Any setting here overrides other configuration of `DMPLEX` adjacency determination.

 19: .seealso: `DMPLEX`, `DMSetAdjacency()`, `DMPlexDistribute()`, `DMPlexPreallocateOperator()`, `DMPlexGetAdjacency()`, `DMPlexGetAdjacencyUser()`
 20: @*/
 21: PetscErrorCode DMPlexSetAdjacencyUser(DM dm, PetscErrorCode (*user)(DM, PetscInt, PetscInt *, PetscInt[], void *), void *ctx)
 22: {
 23:   DM_Plex *mesh = (DM_Plex *)dm->data;

 25:   PetscFunctionBegin;
 27:   mesh->useradjacency    = user;
 28:   mesh->useradjacencyctx = ctx;
 29:   PetscFunctionReturn(PETSC_SUCCESS);
 30: }

 32: /*@C
 33:   DMPlexGetAdjacencyUser - get the user-defined adjacency callback

 35:   Input Parameter:
 36: . dm - The `DM` object

 38:   Output Parameters:
 39: + user - The callback
 40: - ctx  - context for callback evaluation

 42:   Level: advanced

 44: .seealso: `DMPLEX`, `DMSetAdjacency()`, `DMPlexDistribute()`, `DMPlexPreallocateOperator()`, `DMPlexGetAdjacency()`, `DMPlexSetAdjacencyUser()`
 45: @*/
 46: PetscErrorCode DMPlexGetAdjacencyUser(DM dm, PetscErrorCode (**user)(DM, PetscInt, PetscInt *, PetscInt[], void *), void **ctx)
 47: {
 48:   DM_Plex *mesh = (DM_Plex *)dm->data;

 50:   PetscFunctionBegin;
 52:   if (user) *user = mesh->useradjacency;
 53:   if (ctx) *ctx = mesh->useradjacencyctx;
 54:   PetscFunctionReturn(PETSC_SUCCESS);
 55: }

 57: /*@
 58:   DMPlexSetAdjacencyUseAnchors - Define adjacency in the mesh using the point-to-point constraints.

 60:   Input Parameters:
 61: + dm         - The `DM` object
 62: - useAnchors - Flag to use the constraints.  If PETSC_TRUE, then constrained points are omitted from DMPlexGetAdjacency(), and their anchor points appear in their place.

 64:   Level: intermediate

 66: .seealso: `DMPLEX`, `DMGetAdjacency()`, `DMSetAdjacency()`, `DMPlexDistribute()`, `DMPlexPreallocateOperator()`, `DMPlexSetAnchors()`
 67: @*/
 68: PetscErrorCode DMPlexSetAdjacencyUseAnchors(DM dm, PetscBool useAnchors)
 69: {
 70:   DM_Plex *mesh = (DM_Plex *)dm->data;

 72:   PetscFunctionBegin;
 74:   mesh->useAnchors = useAnchors;
 75:   PetscFunctionReturn(PETSC_SUCCESS);
 76: }

 78: /*@
 79:   DMPlexGetAdjacencyUseAnchors - Query whether adjacency in the mesh uses the point-to-point constraints.

 81:   Input Parameter:
 82: . dm - The `DM` object

 84:   Output Parameter:
 85: . useAnchors - Flag to use the closure.  If PETSC_TRUE, then constrained points are omitted from DMPlexGetAdjacency(), and their anchor points appear in their place.

 87:   Level: intermediate

 89: .seealso: `DMPLEX`, `DMPlexSetAdjacencyUseAnchors()`, `DMSetAdjacency()`, `DMGetAdjacency()`, `DMPlexDistribute()`, `DMPlexPreallocateOperator()`, `DMPlexSetAnchors()`
 90: @*/
 91: PetscErrorCode DMPlexGetAdjacencyUseAnchors(DM dm, PetscBool *useAnchors)
 92: {
 93:   DM_Plex *mesh = (DM_Plex *)dm->data;

 95:   PetscFunctionBegin;
 97:   PetscAssertPointer(useAnchors, 2);
 98:   *useAnchors = mesh->useAnchors;
 99:   PetscFunctionReturn(PETSC_SUCCESS);
100: }

102: static PetscErrorCode DMPlexGetAdjacency_Cone_Internal(DM dm, PetscInt p, PetscInt *adjSize, PetscInt adj[])
103: {
104:   const PetscInt *cone   = NULL;
105:   PetscInt        numAdj = 0, maxAdjSize = *adjSize, coneSize, c;

107:   PetscFunctionBeginHot;
108:   PetscCall(DMPlexGetConeSize(dm, p, &coneSize));
109:   PetscCall(DMPlexGetCone(dm, p, &cone));
110:   for (c = 0; c <= coneSize; ++c) {
111:     const PetscInt  point   = !c ? p : cone[c - 1];
112:     const PetscInt *support = NULL;
113:     PetscInt        supportSize, s, q;

115:     PetscCall(DMPlexGetSupportSize(dm, point, &supportSize));
116:     PetscCall(DMPlexGetSupport(dm, point, &support));
117:     for (s = 0; s < supportSize; ++s) {
118:       for (q = 0; q < numAdj || ((void)(adj[numAdj++] = support[s]), 0); ++q) {
119:         if (support[s] == adj[q]) break;
120:       }
121:       PetscCheck(numAdj <= maxAdjSize, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Invalid mesh exceeded adjacency allocation (%" PetscInt_FMT ")", maxAdjSize);
122:     }
123:   }
124:   *adjSize = numAdj;
125:   PetscFunctionReturn(PETSC_SUCCESS);
126: }

128: static PetscErrorCode DMPlexGetAdjacency_Support_Internal(DM dm, PetscInt p, PetscInt *adjSize, PetscInt adj[])
129: {
130:   const PetscInt *support = NULL;
131:   PetscInt        numAdj = 0, maxAdjSize = *adjSize, supportSize, s;

133:   PetscFunctionBeginHot;
134:   PetscCall(DMPlexGetSupportSize(dm, p, &supportSize));
135:   PetscCall(DMPlexGetSupport(dm, p, &support));
136:   for (s = 0; s <= supportSize; ++s) {
137:     const PetscInt  point = !s ? p : support[s - 1];
138:     const PetscInt *cone  = NULL;
139:     PetscInt        coneSize, c, q;

141:     PetscCall(DMPlexGetConeSize(dm, point, &coneSize));
142:     PetscCall(DMPlexGetCone(dm, point, &cone));
143:     for (c = 0; c < coneSize; ++c) {
144:       for (q = 0; q < numAdj || ((void)(adj[numAdj++] = cone[c]), 0); ++q) {
145:         if (cone[c] == adj[q]) break;
146:       }
147:       PetscCheck(numAdj <= maxAdjSize, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Invalid mesh exceeded adjacency allocation (%" PetscInt_FMT ")", maxAdjSize);
148:     }
149:   }
150:   *adjSize = numAdj;
151:   PetscFunctionReturn(PETSC_SUCCESS);
152: }

154: static PetscErrorCode DMPlexGetAdjacency_Transitive_Internal(DM dm, PetscInt p, PetscBool useClosure, PetscInt *adjSize, PetscInt adj[])
155: {
156:   PetscInt *star   = NULL;
157:   PetscInt  numAdj = 0, maxAdjSize = *adjSize, starSize, s;

159:   PetscFunctionBeginHot;
160:   PetscCall(DMPlexGetTransitiveClosure(dm, p, useClosure, &starSize, &star));
161:   for (s = 0; s < starSize * 2; s += 2) {
162:     const PetscInt *closure = NULL;
163:     PetscInt        closureSize, c, q;

165:     PetscCall(DMPlexGetTransitiveClosure(dm, star[s], (PetscBool)!useClosure, &closureSize, (PetscInt **)&closure));
166:     for (c = 0; c < closureSize * 2; c += 2) {
167:       for (q = 0; q < numAdj || ((void)(adj[numAdj++] = closure[c]), 0); ++q) {
168:         if (closure[c] == adj[q]) break;
169:       }
170:       PetscCheck(numAdj <= maxAdjSize, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Invalid mesh exceeded adjacency allocation (%" PetscInt_FMT ")", maxAdjSize);
171:     }
172:     PetscCall(DMPlexRestoreTransitiveClosure(dm, star[s], (PetscBool)!useClosure, &closureSize, (PetscInt **)&closure));
173:   }
174:   PetscCall(DMPlexRestoreTransitiveClosure(dm, p, useClosure, &starSize, &star));
175:   *adjSize = numAdj;
176:   PetscFunctionReturn(PETSC_SUCCESS);
177: }

179: PetscErrorCode DMPlexGetAdjacency_Internal(DM dm, PetscInt p, PetscBool useCone, PetscBool useTransitiveClosure, PetscBool useAnchors, PetscInt *adjSize, PetscInt *adj[])
180: {
181:   static PetscInt asiz       = 0;
182:   PetscInt        maxAnchors = 1;
183:   PetscInt        aStart = -1, aEnd = -1;
184:   PetscInt        maxAdjSize;
185:   PetscSection    aSec = NULL;
186:   IS              aIS  = NULL;
187:   const PetscInt *anchors;
188:   DM_Plex        *mesh = (DM_Plex *)dm->data;

190:   PetscFunctionBeginHot;
191:   if (useAnchors) {
192:     PetscCall(DMPlexGetAnchors(dm, &aSec, &aIS));
193:     if (aSec) {
194:       PetscCall(PetscSectionGetMaxDof(aSec, &maxAnchors));
195:       maxAnchors = PetscMax(1, maxAnchors);
196:       PetscCall(PetscSectionGetChart(aSec, &aStart, &aEnd));
197:       PetscCall(ISGetIndices(aIS, &anchors));
198:     }
199:   }
200:   if (!*adj) {
201:     PetscInt depth, maxC, maxS, maxP, pStart, pEnd;

203:     PetscCall(DMPlexGetChart(dm, &pStart, &pEnd));
204:     PetscCall(DMPlexGetDepth(dm, &depth));
205:     depth = PetscMax(depth, -depth);
206:     PetscCall(DMPlexGetMaxSizes(dm, &maxC, &maxS));
207:     maxP = maxS * maxC;
208:     /* Adjacency can be as large as supp(cl(cell)) or cl(supp(vertex)),
209:            supp(cell) + supp(maxC faces) + supp(maxC^2 edges) + supp(maxC^3 vertices)
210:          = 0 + maxS*maxC + maxS^2*maxC^2 + maxS^3*maxC^3
211:          = \sum^d_{i=0} (maxS*maxC)^i - 1
212:          = (maxS*maxC)^{d+1} - 1 / (maxS*maxC - 1) - 1
213:       We could improve this by getting the max by strata:
214:            supp[d](cell) + supp[d-1](maxC[d] faces) + supp[1](maxC[d]*maxC[d-1] edges) + supp[0](maxC[d]*maxC[d-1]*maxC[d-2] vertices)
215:          = 0 + maxS[d-1]*maxC[d] + maxS[1]*maxC[d]*maxC[d-1] + maxS[0]*maxC[d]*maxC[d-1]*maxC[d-2]
216:       and the same with S and C reversed
217:     */
218:     if ((depth == 3 && maxP > 200) || (depth == 2 && maxP > 580)) asiz = pEnd - pStart;
219:     else asiz = (maxP > 1) ? ((PetscPowInt(maxP, depth + 1) - 1) / (maxP - 1)) : depth + 1;
220:     asiz *= maxAnchors;
221:     asiz = PetscMin(asiz, pEnd - pStart);
222:     PetscCall(PetscMalloc1(asiz, adj));
223:   }
224:   if (*adjSize < 0) *adjSize = asiz;
225:   maxAdjSize = *adjSize;
226:   if (mesh->useradjacency) {
227:     PetscCall((*mesh->useradjacency)(dm, p, adjSize, *adj, mesh->useradjacencyctx));
228:   } else if (useTransitiveClosure) {
229:     PetscCall(DMPlexGetAdjacency_Transitive_Internal(dm, p, useCone, adjSize, *adj));
230:   } else if (useCone) {
231:     PetscCall(DMPlexGetAdjacency_Cone_Internal(dm, p, adjSize, *adj));
232:   } else {
233:     PetscCall(DMPlexGetAdjacency_Support_Internal(dm, p, adjSize, *adj));
234:   }
235:   if (useAnchors && aSec) {
236:     PetscInt  origSize = *adjSize;
237:     PetscInt  numAdj   = origSize;
238:     PetscInt  i        = 0, j;
239:     PetscInt *orig     = *adj;

241:     while (i < origSize) {
242:       PetscInt p    = orig[i];
243:       PetscInt aDof = 0;

245:       if (p >= aStart && p < aEnd) PetscCall(PetscSectionGetDof(aSec, p, &aDof));
246:       if (aDof) {
247:         PetscInt aOff;
248:         PetscInt s, q;

250:         for (j = i + 1; j < numAdj; j++) orig[j - 1] = orig[j];
251:         origSize--;
252:         numAdj--;
253:         PetscCall(PetscSectionGetOffset(aSec, p, &aOff));
254:         for (s = 0; s < aDof; ++s) {
255:           for (q = 0; q < numAdj || ((void)(orig[numAdj++] = anchors[aOff + s]), 0); ++q) {
256:             if (anchors[aOff + s] == orig[q]) break;
257:           }
258:           PetscCheck(numAdj <= maxAdjSize, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Invalid mesh exceeded adjacency allocation (%" PetscInt_FMT ")", maxAdjSize);
259:         }
260:       } else {
261:         i++;
262:       }
263:     }
264:     *adjSize = numAdj;
265:     PetscCall(ISRestoreIndices(aIS, &anchors));
266:   }
267:   PetscFunctionReturn(PETSC_SUCCESS);
268: }

270: /*@
271:   DMPlexGetAdjacency - Return all points adjacent to the given point

273:   Input Parameters:
274: + dm - The `DM` object
275: - p  - The point

277:   Input/Output Parameters:
278: + adjSize - The maximum size of `adj` if it is non-`NULL`, or `PETSC_DETERMINE`;
279:             on output the number of adjacent points
280: - adj     - Either `NULL` so that the array is allocated, or an existing array with size `adjSize`;
281:         on output contains the adjacent points

283:   Level: advanced

285:   Notes:
286:   The user must `PetscFree()` the `adj` array if it was not passed in.

288: .seealso: `DMPLEX`, `DMSetAdjacency()`, `DMPlexDistribute()`, `DMCreateMatrix()`, `DMPlexPreallocateOperator()`
289: @*/
290: PetscErrorCode DMPlexGetAdjacency(DM dm, PetscInt p, PetscInt *adjSize, PetscInt *adj[])
291: {
292:   PetscBool useCone, useClosure, useAnchors;

294:   PetscFunctionBeginHot;
296:   PetscAssertPointer(adjSize, 3);
297:   PetscAssertPointer(adj, 4);
298:   PetscCall(DMGetBasicAdjacency(dm, &useCone, &useClosure));
299:   PetscCall(DMPlexGetAdjacencyUseAnchors(dm, &useAnchors));
300:   PetscCall(DMPlexGetAdjacency_Internal(dm, p, useCone, useClosure, useAnchors, adjSize, adj));
301:   PetscFunctionReturn(PETSC_SUCCESS);
302: }

304: /*@
305:   DMPlexCreateTwoSidedProcessSF - Create an `PetscSF` which just has process connectivity

307:   Collective

309:   Input Parameters:
310: + dm              - The `DM`
311: . sfPoint         - The `PetscSF` which encodes point connectivity
312: . rootRankSection - to be documented
313: . rootRanks       - to be documented
314: . leafRankSection - to be documented
315: - leafRanks       - to be documented

317:   Output Parameters:
318: + processRanks - A list of process neighbors, or `NULL`
319: - sfProcess    - An `PetscSF` encoding the two-sided process connectivity, or `NULL`

321:   Level: developer

323: .seealso: `DMPLEX`, `PetscSFCreate()`, `DMPlexCreateProcessSF()`
324: @*/
325: PetscErrorCode DMPlexCreateTwoSidedProcessSF(DM dm, PetscSF sfPoint, PetscSection rootRankSection, IS rootRanks, PetscSection leafRankSection, IS leafRanks, IS *processRanks, PetscSF *sfProcess)
326: {
327:   const PetscSFNode *remotePoints;
328:   PetscInt          *localPointsNew;
329:   PetscSFNode       *remotePointsNew;
330:   const PetscInt    *nranks;
331:   PetscInt          *ranksNew;
332:   PetscBT            neighbors;
333:   PetscInt           pStart, pEnd, p, numLeaves, l, numNeighbors, n;
334:   PetscMPIInt        size, proc, rank;

336:   PetscFunctionBegin;
339:   if (processRanks) PetscAssertPointer(processRanks, 7);
340:   if (sfProcess) PetscAssertPointer(sfProcess, 8);
341:   PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)dm), &size));
342:   PetscCallMPI(MPI_Comm_rank(PetscObjectComm((PetscObject)dm), &rank));
343:   PetscCall(PetscSFGetGraph(sfPoint, NULL, &numLeaves, NULL, &remotePoints));
344:   PetscCall(PetscBTCreate(size, &neighbors));
345:   PetscCall(PetscBTMemzero(size, neighbors));
346:   /* Compute root-to-leaf process connectivity */
347:   PetscCall(PetscSectionGetChart(rootRankSection, &pStart, &pEnd));
348:   PetscCall(ISGetIndices(rootRanks, &nranks));
349:   for (p = pStart; p < pEnd; ++p) {
350:     PetscInt ndof, noff, n;

352:     PetscCall(PetscSectionGetDof(rootRankSection, p, &ndof));
353:     PetscCall(PetscSectionGetOffset(rootRankSection, p, &noff));
354:     for (n = 0; n < ndof; ++n) PetscCall(PetscBTSet(neighbors, nranks[noff + n]));
355:   }
356:   PetscCall(ISRestoreIndices(rootRanks, &nranks));
357:   /* Compute leaf-to-neighbor process connectivity */
358:   PetscCall(PetscSectionGetChart(leafRankSection, &pStart, &pEnd));
359:   PetscCall(ISGetIndices(leafRanks, &nranks));
360:   for (p = pStart; p < pEnd; ++p) {
361:     PetscInt ndof, noff, n;

363:     PetscCall(PetscSectionGetDof(leafRankSection, p, &ndof));
364:     PetscCall(PetscSectionGetOffset(leafRankSection, p, &noff));
365:     for (n = 0; n < ndof; ++n) PetscCall(PetscBTSet(neighbors, nranks[noff + n]));
366:   }
367:   PetscCall(ISRestoreIndices(leafRanks, &nranks));
368:   /* Compute leaf-to-root process connectivity */
369:   for (l = 0; l < numLeaves; ++l) PetscCall(PetscBTSet(neighbors, remotePoints[l].rank));
370:   /* Calculate edges */
371:   PetscCall(PetscBTClear(neighbors, rank));
372:   for (proc = 0, numNeighbors = 0; proc < size; ++proc) {
373:     if (PetscBTLookup(neighbors, proc)) ++numNeighbors;
374:   }
375:   PetscCall(PetscMalloc1(numNeighbors, &ranksNew));
376:   PetscCall(PetscMalloc1(numNeighbors, &localPointsNew));
377:   PetscCall(PetscMalloc1(numNeighbors, &remotePointsNew));
378:   for (proc = 0, n = 0; proc < size; ++proc) {
379:     if (PetscBTLookup(neighbors, proc)) {
380:       ranksNew[n]              = proc;
381:       localPointsNew[n]        = proc;
382:       remotePointsNew[n].index = rank;
383:       remotePointsNew[n].rank  = proc;
384:       ++n;
385:     }
386:   }
387:   PetscCall(PetscBTDestroy(&neighbors));
388:   if (processRanks) PetscCall(ISCreateGeneral(PetscObjectComm((PetscObject)dm), numNeighbors, ranksNew, PETSC_OWN_POINTER, processRanks));
389:   else PetscCall(PetscFree(ranksNew));
390:   if (sfProcess) {
391:     PetscCall(PetscSFCreate(PetscObjectComm((PetscObject)dm), sfProcess));
392:     PetscCall(PetscObjectSetName((PetscObject)*sfProcess, "Two-Sided Process SF"));
393:     PetscCall(PetscSFSetFromOptions(*sfProcess));
394:     PetscCall(PetscSFSetGraph(*sfProcess, size, numNeighbors, localPointsNew, PETSC_OWN_POINTER, remotePointsNew, PETSC_OWN_POINTER));
395:   }
396:   PetscFunctionReturn(PETSC_SUCCESS);
397: }

399: /*@
400:   DMPlexDistributeOwnership - Compute owner information for shared points. This basically gets two-sided for an SF.

402:   Collective

404:   Input Parameter:
405: . dm - The `DM`

407:   Output Parameters:
408: + rootSection - The number of leaves for a given root point
409: . rootrank    - The rank of each edge into the root point
410: . leafSection - The number of processes sharing a given leaf point
411: - leafrank    - The rank of each process sharing a leaf point

413:   Level: developer

415: .seealso: `DMPLEX`, `DMPlexCreateOverlapLabel()`, `DMPlexDistribute()`, `DMPlexDistributeOverlap()`
416: @*/
417: PetscErrorCode DMPlexDistributeOwnership(DM dm, PetscSection rootSection, IS *rootrank, PetscSection leafSection, IS *leafrank)
418: {
419:   MPI_Comm        comm;
420:   PetscSF         sfPoint;
421:   const PetscInt *rootdegree;
422:   PetscInt       *myrank, *remoterank;
423:   PetscInt        pStart, pEnd, p, nedges;
424:   PetscMPIInt     rank;

426:   PetscFunctionBegin;
427:   PetscCall(PetscObjectGetComm((PetscObject)dm, &comm));
428:   PetscCallMPI(MPI_Comm_rank(comm, &rank));
429:   PetscCall(DMPlexGetChart(dm, &pStart, &pEnd));
430:   PetscCall(DMGetPointSF(dm, &sfPoint));
431:   /* Compute number of leaves for each root */
432:   PetscCall(PetscObjectSetName((PetscObject)rootSection, "Root Section"));
433:   PetscCall(PetscSectionSetChart(rootSection, pStart, pEnd));
434:   PetscCall(PetscSFComputeDegreeBegin(sfPoint, &rootdegree));
435:   PetscCall(PetscSFComputeDegreeEnd(sfPoint, &rootdegree));
436:   for (p = pStart; p < pEnd; ++p) PetscCall(PetscSectionSetDof(rootSection, p, rootdegree[p - pStart]));
437:   PetscCall(PetscSectionSetUp(rootSection));
438:   /* Gather rank of each leaf to root */
439:   PetscCall(PetscSectionGetStorageSize(rootSection, &nedges));
440:   PetscCall(PetscMalloc1(pEnd - pStart, &myrank));
441:   PetscCall(PetscMalloc1(nedges, &remoterank));
442:   for (p = 0; p < pEnd - pStart; ++p) myrank[p] = rank;
443:   PetscCall(PetscSFGatherBegin(sfPoint, MPIU_INT, myrank, remoterank));
444:   PetscCall(PetscSFGatherEnd(sfPoint, MPIU_INT, myrank, remoterank));
445:   PetscCall(PetscFree(myrank));
446:   PetscCall(ISCreateGeneral(comm, nedges, remoterank, PETSC_OWN_POINTER, rootrank));
447:   /* Distribute remote ranks to leaves */
448:   PetscCall(PetscObjectSetName((PetscObject)leafSection, "Leaf Section"));
449:   PetscCall(DMPlexDistributeFieldIS(dm, sfPoint, rootSection, *rootrank, leafSection, leafrank));
450:   PetscFunctionReturn(PETSC_SUCCESS);
451: }

453: /*@C
454:   DMPlexCreateOverlapLabel - Compute a label indicating what overlap points should be sent to new processes

456:   Collective

458:   Input Parameters:
459: + dm          - The `DM`
460: . levels      - Number of overlap levels
461: . rootSection - The number of leaves for a given root point
462: . rootrank    - The rank of each edge into the root point
463: . leafSection - The number of processes sharing a given leaf point
464: - leafrank    - The rank of each process sharing a leaf point

466:   Output Parameter:
467: . ovLabel - `DMLabel` containing remote overlap contributions as point/rank pairings

469:   Level: developer

471: .seealso: `DMPLEX`, `DMPlexCreateOverlapLabelFromLabels()`, `DMPlexGetAdjacency()`, `DMPlexDistributeOwnership()`, `DMPlexDistribute()`
472: @*/
473: PetscErrorCode DMPlexCreateOverlapLabel(DM dm, PetscInt levels, PetscSection rootSection, IS rootrank, PetscSection leafSection, IS leafrank, DMLabel *ovLabel)
474: {
475:   MPI_Comm           comm;
476:   DMLabel            ovAdjByRank; /* A DMLabel containing all points adjacent to shared points, separated by rank (value in label) */
477:   PetscSF            sfPoint;
478:   const PetscSFNode *remote;
479:   const PetscInt    *local;
480:   const PetscInt    *nrank, *rrank;
481:   PetscInt          *adj = NULL;
482:   PetscInt           pStart, pEnd, p, sStart, sEnd, nleaves, l;
483:   PetscMPIInt        rank, size;
484:   PetscBool          flg;

486:   PetscFunctionBegin;
487:   *ovLabel = NULL;
488:   PetscCall(PetscObjectGetComm((PetscObject)dm, &comm));
489:   PetscCallMPI(MPI_Comm_size(comm, &size));
490:   PetscCallMPI(MPI_Comm_rank(comm, &rank));
491:   if (size == 1) PetscFunctionReturn(PETSC_SUCCESS);
492:   PetscCall(DMGetPointSF(dm, &sfPoint));
493:   PetscCall(DMPlexGetChart(dm, &pStart, &pEnd));
494:   if (!levels) {
495:     /* Add owned points */
496:     PetscCall(DMLabelCreate(PETSC_COMM_SELF, "Overlap label", ovLabel));
497:     for (p = pStart; p < pEnd; ++p) PetscCall(DMLabelSetValue(*ovLabel, p, rank));
498:     PetscFunctionReturn(PETSC_SUCCESS);
499:   }
500:   PetscCall(PetscSectionGetChart(leafSection, &sStart, &sEnd));
501:   PetscCall(PetscSFGetGraph(sfPoint, NULL, &nleaves, &local, &remote));
502:   PetscCall(DMLabelCreate(PETSC_COMM_SELF, "Overlap adjacency", &ovAdjByRank));
503:   /* Handle leaves: shared with the root point */
504:   for (l = 0; l < nleaves; ++l) {
505:     PetscInt adjSize = PETSC_DETERMINE, a;

507:     PetscCall(DMPlexGetAdjacency(dm, local ? local[l] : l, &adjSize, &adj));
508:     for (a = 0; a < adjSize; ++a) PetscCall(DMLabelSetValue(ovAdjByRank, adj[a], remote[l].rank));
509:   }
510:   PetscCall(ISGetIndices(rootrank, &rrank));
511:   PetscCall(ISGetIndices(leafrank, &nrank));
512:   /* Handle roots */
513:   for (p = pStart; p < pEnd; ++p) {
514:     PetscInt adjSize = PETSC_DETERMINE, neighbors = 0, noff, n, a;

516:     if ((p >= sStart) && (p < sEnd)) {
517:       /* Some leaves share a root with other leaves on different processes */
518:       PetscCall(PetscSectionGetDof(leafSection, p, &neighbors));
519:       if (neighbors) {
520:         PetscCall(PetscSectionGetOffset(leafSection, p, &noff));
521:         PetscCall(DMPlexGetAdjacency(dm, p, &adjSize, &adj));
522:         for (n = 0; n < neighbors; ++n) {
523:           const PetscInt remoteRank = nrank[noff + n];

525:           if (remoteRank == rank) continue;
526:           for (a = 0; a < adjSize; ++a) PetscCall(DMLabelSetValue(ovAdjByRank, adj[a], remoteRank));
527:         }
528:       }
529:     }
530:     /* Roots are shared with leaves */
531:     PetscCall(PetscSectionGetDof(rootSection, p, &neighbors));
532:     if (!neighbors) continue;
533:     PetscCall(PetscSectionGetOffset(rootSection, p, &noff));
534:     PetscCall(DMPlexGetAdjacency(dm, p, &adjSize, &adj));
535:     for (n = 0; n < neighbors; ++n) {
536:       const PetscInt remoteRank = rrank[noff + n];

538:       if (remoteRank == rank) continue;
539:       for (a = 0; a < adjSize; ++a) PetscCall(DMLabelSetValue(ovAdjByRank, adj[a], remoteRank));
540:     }
541:   }
542:   PetscCall(PetscFree(adj));
543:   PetscCall(ISRestoreIndices(rootrank, &rrank));
544:   PetscCall(ISRestoreIndices(leafrank, &nrank));
545:   /* Add additional overlap levels */
546:   for (l = 1; l < levels; l++) {
547:     /* Propagate point donations over SF to capture remote connections */
548:     PetscCall(DMPlexPartitionLabelPropagate(dm, ovAdjByRank));
549:     /* Add next level of point donations to the label */
550:     PetscCall(DMPlexPartitionLabelAdjacency(dm, ovAdjByRank));
551:   }
552:   /* We require the closure in the overlap */
553:   PetscCall(DMPlexPartitionLabelClosure(dm, ovAdjByRank));
554:   PetscCall(PetscOptionsHasName(((PetscObject)dm)->options, ((PetscObject)dm)->prefix, "-overlap_view", &flg));
555:   if (flg) {
556:     PetscViewer viewer;
557:     PetscCall(PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)dm), &viewer));
558:     PetscCall(DMLabelView(ovAdjByRank, viewer));
559:   }
560:   /* Invert sender to receiver label */
561:   PetscCall(DMLabelCreate(PETSC_COMM_SELF, "Overlap label", ovLabel));
562:   PetscCall(DMPlexPartitionLabelInvert(dm, ovAdjByRank, NULL, *ovLabel));
563:   /* Add owned points, except for shared local points */
564:   for (p = pStart; p < pEnd; ++p) PetscCall(DMLabelSetValue(*ovLabel, p, rank));
565:   for (l = 0; l < nleaves; ++l) {
566:     PetscCall(DMLabelClearValue(*ovLabel, local[l], rank));
567:     PetscCall(DMLabelSetValue(*ovLabel, remote[l].index, remote[l].rank));
568:   }
569:   /* Clean up */
570:   PetscCall(DMLabelDestroy(&ovAdjByRank));
571:   PetscFunctionReturn(PETSC_SUCCESS);
572: }

574: static PetscErrorCode HandlePoint_Private(DM dm, PetscInt p, PetscSection section, const PetscInt ranks[], PetscInt numExLabels, const DMLabel exLabel[], const PetscInt exValue[], DMLabel ovAdjByRank)
575: {
576:   PetscInt neighbors, el;

578:   PetscFunctionBegin;
579:   PetscCall(PetscSectionGetDof(section, p, &neighbors));
580:   if (neighbors) {
581:     PetscInt   *adj     = NULL;
582:     PetscInt    adjSize = PETSC_DETERMINE, noff, n, a;
583:     PetscMPIInt rank;

585:     PetscCallMPI(MPI_Comm_rank(PetscObjectComm((PetscObject)dm), &rank));
586:     PetscCall(PetscSectionGetOffset(section, p, &noff));
587:     PetscCall(DMPlexGetAdjacency(dm, p, &adjSize, &adj));
588:     for (n = 0; n < neighbors; ++n) {
589:       const PetscInt remoteRank = ranks[noff + n];

591:       if (remoteRank == rank) continue;
592:       for (a = 0; a < adjSize; ++a) {
593:         PetscBool insert = PETSC_TRUE;

595:         for (el = 0; el < numExLabels; ++el) {
596:           PetscInt exVal;
597:           PetscCall(DMLabelGetValue(exLabel[el], adj[a], &exVal));
598:           if (exVal == exValue[el]) {
599:             insert = PETSC_FALSE;
600:             break;
601:           }
602:         }
603:         if (insert) PetscCall(DMLabelSetValue(ovAdjByRank, adj[a], remoteRank));
604:       }
605:     }
606:     PetscCall(PetscFree(adj));
607:   }
608:   PetscFunctionReturn(PETSC_SUCCESS);
609: }

611: /*@C
612:   DMPlexCreateOverlapLabelFromLabels - Compute a label indicating what overlap points should be sent to new processes

614:   Collective

616:   Input Parameters:
617: + dm          - The `DM`
618: . numLabels   - The number of labels to draw candidate points from
619: . label       - An array of labels containing candidate points
620: . value       - An array of label values marking the candidate points
621: . numExLabels - The number of labels to use for exclusion
622: . exLabel     - An array of labels indicating points to be excluded, or `NULL`
623: . exValue     - An array of label values to be excluded, or `NULL`
624: . rootSection - The number of leaves for a given root point
625: . rootrank    - The rank of each edge into the root point
626: . leafSection - The number of processes sharing a given leaf point
627: - leafrank    - The rank of each process sharing a leaf point

629:   Output Parameter:
630: . ovLabel - `DMLabel` containing remote overlap contributions as point/rank pairings

632:   Level: developer

634:   Note:
635:   The candidate points are only added to the overlap if they are adjacent to a shared point

637: .seealso: `DMPLEX`, `DMPlexCreateOverlapLabel()`, `DMPlexGetAdjacency()`, `DMPlexDistributeOwnership()`, `DMPlexDistribute()`
638: @*/
639: PetscErrorCode DMPlexCreateOverlapLabelFromLabels(DM dm, PetscInt numLabels, const DMLabel label[], const PetscInt value[], PetscInt numExLabels, const DMLabel exLabel[], const PetscInt exValue[], PetscSection rootSection, IS rootrank, PetscSection leafSection, IS leafrank, DMLabel *ovLabel)
640: {
641:   MPI_Comm           comm;
642:   DMLabel            ovAdjByRank; /* A DMLabel containing all points adjacent to shared points, separated by rank (value in label) */
643:   PetscSF            sfPoint;
644:   const PetscSFNode *remote;
645:   const PetscInt    *local;
646:   const PetscInt    *nrank, *rrank;
647:   PetscInt          *adj = NULL;
648:   PetscInt           pStart, pEnd, p, sStart, sEnd, nleaves, l, el;
649:   PetscMPIInt        rank, size;
650:   PetscBool          flg;

652:   PetscFunctionBegin;
653:   *ovLabel = NULL;
654:   PetscCall(PetscObjectGetComm((PetscObject)dm, &comm));
655:   PetscCallMPI(MPI_Comm_size(comm, &size));
656:   PetscCallMPI(MPI_Comm_rank(comm, &rank));
657:   if (size == 1) PetscFunctionReturn(PETSC_SUCCESS);
658:   PetscCall(DMGetPointSF(dm, &sfPoint));
659:   PetscCall(DMPlexGetChart(dm, &pStart, &pEnd));
660:   PetscCall(PetscSectionGetChart(leafSection, &sStart, &sEnd));
661:   PetscCall(PetscSFGetGraph(sfPoint, NULL, &nleaves, &local, &remote));
662:   PetscCall(DMLabelCreate(PETSC_COMM_SELF, "Overlap adjacency", &ovAdjByRank));
663:   PetscCall(ISGetIndices(rootrank, &rrank));
664:   PetscCall(ISGetIndices(leafrank, &nrank));
665:   for (l = 0; l < numLabels; ++l) {
666:     IS              valIS;
667:     const PetscInt *points;
668:     PetscInt        n;

670:     PetscCall(DMLabelGetStratumIS(label[l], value[l], &valIS));
671:     if (!valIS) continue;
672:     PetscCall(ISGetIndices(valIS, &points));
673:     PetscCall(ISGetLocalSize(valIS, &n));
674:     for (PetscInt i = 0; i < n; ++i) {
675:       const PetscInt p = points[i];

677:       if ((p >= sStart) && (p < sEnd)) {
678:         PetscInt loc, adjSize = PETSC_DETERMINE;

680:         /* Handle leaves: shared with the root point */
681:         if (local) PetscCall(PetscFindInt(p, nleaves, local, &loc));
682:         else loc = (p >= 0 && p < nleaves) ? p : -1;
683:         if (loc >= 0) {
684:           const PetscInt remoteRank = remote[loc].rank;

686:           PetscCall(DMPlexGetAdjacency(dm, p, &adjSize, &adj));
687:           for (PetscInt a = 0; a < adjSize; ++a) {
688:             PetscBool insert = PETSC_TRUE;

690:             for (el = 0; el < numExLabels; ++el) {
691:               PetscInt exVal;
692:               PetscCall(DMLabelGetValue(exLabel[el], adj[a], &exVal));
693:               if (exVal == exValue[el]) {
694:                 insert = PETSC_FALSE;
695:                 break;
696:               }
697:             }
698:             if (insert) PetscCall(DMLabelSetValue(ovAdjByRank, adj[a], remoteRank));
699:           }
700:         }
701:         /* Some leaves share a root with other leaves on different processes */
702:         PetscCall(HandlePoint_Private(dm, p, leafSection, nrank, numExLabels, exLabel, exValue, ovAdjByRank));
703:       }
704:       /* Roots are shared with leaves */
705:       PetscCall(HandlePoint_Private(dm, p, rootSection, rrank, numExLabels, exLabel, exValue, ovAdjByRank));
706:     }
707:     PetscCall(ISRestoreIndices(valIS, &points));
708:     PetscCall(ISDestroy(&valIS));
709:   }
710:   PetscCall(PetscFree(adj));
711:   PetscCall(ISRestoreIndices(rootrank, &rrank));
712:   PetscCall(ISRestoreIndices(leafrank, &nrank));
713:   /* We require the closure in the overlap */
714:   PetscCall(DMPlexPartitionLabelClosure(dm, ovAdjByRank));
715:   PetscCall(PetscOptionsHasName(((PetscObject)dm)->options, ((PetscObject)dm)->prefix, "-overlap_view", &flg));
716:   if (flg) {
717:     PetscViewer viewer;
718:     PetscCall(PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)dm), &viewer));
719:     PetscCall(DMLabelView(ovAdjByRank, viewer));
720:   }
721:   /* Invert sender to receiver label */
722:   PetscCall(DMLabelCreate(PETSC_COMM_SELF, "Overlap label", ovLabel));
723:   PetscCall(DMPlexPartitionLabelInvert(dm, ovAdjByRank, NULL, *ovLabel));
724:   /* Add owned points, except for shared local points */
725:   for (p = pStart; p < pEnd; ++p) PetscCall(DMLabelSetValue(*ovLabel, p, rank));
726:   for (l = 0; l < nleaves; ++l) {
727:     PetscCall(DMLabelClearValue(*ovLabel, local[l], rank));
728:     PetscCall(DMLabelSetValue(*ovLabel, remote[l].index, remote[l].rank));
729:   }
730:   /* Clean up */
731:   PetscCall(DMLabelDestroy(&ovAdjByRank));
732:   PetscFunctionReturn(PETSC_SUCCESS);
733: }

735: /*@
736:   DMPlexCreateOverlapMigrationSF - Create a `PetscSF` describing the new mesh distribution to make the overlap described by the input `PetscSF`

738:   Collective

740:   Input Parameters:
741: + dm        - The `DM`
742: - overlapSF - The `PetscSF` mapping ghost points in overlap to owner points on other processes

744:   Output Parameter:
745: . migrationSF - A `PetscSF` that maps original points in old locations to points in new locations

747:   Level: developer

749: .seealso: `DMPLEX`, `DMPlexCreateOverlapLabel()`, `DMPlexDistributeOverlap()`, `DMPlexDistribute()`
750: @*/
751: PetscErrorCode DMPlexCreateOverlapMigrationSF(DM dm, PetscSF overlapSF, PetscSF *migrationSF)
752: {
753:   MPI_Comm           comm;
754:   PetscMPIInt        rank, size;
755:   PetscInt           d, dim, p, pStart, pEnd, nroots, nleaves, newLeaves, point, numSharedPoints;
756:   PetscInt          *pointDepths, *remoteDepths, *ilocal;
757:   PetscInt          *depthRecv, *depthShift, *depthIdx;
758:   PetscSFNode       *iremote;
759:   PetscSF            pointSF;
760:   const PetscInt    *sharedLocal;
761:   const PetscSFNode *overlapRemote, *sharedRemote;

763:   PetscFunctionBegin;
765:   PetscCall(PetscObjectGetComm((PetscObject)dm, &comm));
766:   PetscCallMPI(MPI_Comm_rank(comm, &rank));
767:   PetscCallMPI(MPI_Comm_size(comm, &size));
768:   PetscCall(DMGetDimension(dm, &dim));

770:   /* Before building the migration SF we need to know the new stratum offsets */
771:   PetscCall(PetscSFGetGraph(overlapSF, &nroots, &nleaves, NULL, &overlapRemote));
772:   PetscCall(PetscMalloc2(nroots, &pointDepths, nleaves, &remoteDepths));
773:   for (d = 0; d < dim + 1; d++) {
774:     PetscCall(DMPlexGetDepthStratum(dm, d, &pStart, &pEnd));
775:     for (p = pStart; p < pEnd; p++) pointDepths[p] = d;
776:   }
777:   for (p = 0; p < nleaves; p++) remoteDepths[p] = -1;
778:   PetscCall(PetscSFBcastBegin(overlapSF, MPIU_INT, pointDepths, remoteDepths, MPI_REPLACE));
779:   PetscCall(PetscSFBcastEnd(overlapSF, MPIU_INT, pointDepths, remoteDepths, MPI_REPLACE));

781:   /* Count received points in each stratum and compute the internal strata shift */
782:   PetscCall(PetscMalloc3(dim + 1, &depthRecv, dim + 1, &depthShift, dim + 1, &depthIdx));
783:   for (d = 0; d < dim + 1; d++) depthRecv[d] = 0;
784:   for (p = 0; p < nleaves; p++) depthRecv[remoteDepths[p]]++;
785:   depthShift[dim] = 0;
786:   for (d = 0; d < dim; d++) depthShift[d] = depthRecv[dim];
787:   for (d = 1; d < dim; d++) depthShift[d] += depthRecv[0];
788:   for (d = dim - 2; d > 0; d--) depthShift[d] += depthRecv[d + 1];
789:   for (d = 0; d < dim + 1; d++) {
790:     PetscCall(DMPlexGetDepthStratum(dm, d, &pStart, &pEnd));
791:     depthIdx[d] = pStart + depthShift[d];
792:   }

794:   /* Form the overlap SF build an SF that describes the full overlap migration SF */
795:   PetscCall(DMPlexGetChart(dm, &pStart, &pEnd));
796:   newLeaves = pEnd - pStart + nleaves;
797:   PetscCall(PetscMalloc1(newLeaves, &ilocal));
798:   PetscCall(PetscMalloc1(newLeaves, &iremote));
799:   /* First map local points to themselves */
800:   for (d = 0; d < dim + 1; d++) {
801:     PetscCall(DMPlexGetDepthStratum(dm, d, &pStart, &pEnd));
802:     for (p = pStart; p < pEnd; p++) {
803:       point                = p + depthShift[d];
804:       ilocal[point]        = point;
805:       iremote[point].index = p;
806:       iremote[point].rank  = rank;
807:       depthIdx[d]++;
808:     }
809:   }

811:   /* Add in the remote roots for currently shared points */
812:   PetscCall(DMGetPointSF(dm, &pointSF));
813:   PetscCall(PetscSFGetGraph(pointSF, NULL, &numSharedPoints, &sharedLocal, &sharedRemote));
814:   for (d = 0; d < dim + 1; d++) {
815:     PetscCall(DMPlexGetDepthStratum(dm, d, &pStart, &pEnd));
816:     for (p = 0; p < numSharedPoints; p++) {
817:       if (pStart <= sharedLocal[p] && sharedLocal[p] < pEnd) {
818:         point                = sharedLocal[p] + depthShift[d];
819:         iremote[point].index = sharedRemote[p].index;
820:         iremote[point].rank  = sharedRemote[p].rank;
821:       }
822:     }
823:   }

825:   /* Now add the incoming overlap points */
826:   for (p = 0; p < nleaves; p++) {
827:     point                = depthIdx[remoteDepths[p]];
828:     ilocal[point]        = point;
829:     iremote[point].index = overlapRemote[p].index;
830:     iremote[point].rank  = overlapRemote[p].rank;
831:     depthIdx[remoteDepths[p]]++;
832:   }
833:   PetscCall(PetscFree2(pointDepths, remoteDepths));

835:   PetscCall(PetscSFCreate(comm, migrationSF));
836:   PetscCall(PetscObjectSetName((PetscObject)*migrationSF, "Overlap Migration SF"));
837:   PetscCall(PetscSFSetFromOptions(*migrationSF));
838:   PetscCall(DMPlexGetChart(dm, &pStart, &pEnd));
839:   PetscCall(PetscSFSetGraph(*migrationSF, pEnd - pStart, newLeaves, ilocal, PETSC_OWN_POINTER, iremote, PETSC_OWN_POINTER));

841:   PetscCall(PetscFree3(depthRecv, depthShift, depthIdx));
842:   PetscFunctionReturn(PETSC_SUCCESS);
843: }

845: /*@
846:   DMPlexStratifyMigrationSF - Rearrange the leaves of a migration sf for stratification.

848:   Input Parameters:
849: + dm - The DM
850: - sf - A star forest with non-ordered leaves, usually defining a DM point migration

852:   Output Parameter:
853: . migrationSF - A star forest with added leaf indirection that ensures the resulting DM is stratified

855:   Level: developer

857:   Note:
858:   This lexicographically sorts by (depth, cellType)

860: .seealso: `DMPLEX`, `DMPlexPartitionLabelCreateSF()`, `DMPlexDistribute()`, `DMPlexDistributeOverlap()`
861: @*/
862: PetscErrorCode DMPlexStratifyMigrationSF(DM dm, PetscSF sf, PetscSF *migrationSF)
863: {
864:   MPI_Comm           comm;
865:   PetscMPIInt        rank, size;
866:   PetscInt           d, ldepth, depth, dim, p, pStart, pEnd, nroots, nleaves;
867:   PetscSFNode       *pointDepths, *remoteDepths;
868:   PetscInt          *ilocal;
869:   PetscInt          *depthRecv, *depthShift, *depthIdx;
870:   PetscInt          *ctRecv, *ctShift, *ctIdx;
871:   const PetscSFNode *iremote;

873:   PetscFunctionBegin;
875:   PetscCall(PetscObjectGetComm((PetscObject)dm, &comm));
876:   PetscCallMPI(MPI_Comm_rank(comm, &rank));
877:   PetscCallMPI(MPI_Comm_size(comm, &size));
878:   PetscCall(DMPlexGetDepth(dm, &ldepth));
879:   PetscCall(DMGetDimension(dm, &dim));
880:   PetscCallMPI(MPIU_Allreduce(&ldepth, &depth, 1, MPIU_INT, MPI_MAX, comm));
881:   PetscCheck(!(ldepth >= 0) || !(depth != ldepth), PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Inconsistent Plex depth %" PetscInt_FMT " != %" PetscInt_FMT, ldepth, depth);
882:   PetscCall(PetscLogEventBegin(DMPLEX_PartStratSF, dm, 0, 0, 0));

884:   /* Before building the migration SF we need to know the new stratum offsets */
885:   PetscCall(PetscSFGetGraph(sf, &nroots, &nleaves, NULL, &iremote));
886:   PetscCall(PetscMalloc2(nroots, &pointDepths, nleaves, &remoteDepths));
887:   for (d = 0; d < depth + 1; ++d) {
888:     PetscCall(DMPlexGetDepthStratum(dm, d, &pStart, &pEnd));
889:     for (p = pStart; p < pEnd; ++p) {
890:       DMPolytopeType ct;

892:       PetscCall(DMPlexGetCellType(dm, p, &ct));
893:       pointDepths[p].index = d;
894:       pointDepths[p].rank  = ct;
895:     }
896:   }
897:   for (p = 0; p < nleaves; ++p) {
898:     remoteDepths[p].index = -1;
899:     remoteDepths[p].rank  = -1;
900:   }
901:   PetscCall(PetscSFBcastBegin(sf, MPIU_SF_NODE, pointDepths, remoteDepths, MPI_REPLACE));
902:   PetscCall(PetscSFBcastEnd(sf, MPIU_SF_NODE, pointDepths, remoteDepths, MPI_REPLACE));
903:   /* Count received points in each stratum and compute the internal strata shift */
904:   PetscCall(PetscCalloc6(depth + 1, &depthRecv, depth + 1, &depthShift, depth + 1, &depthIdx, DM_NUM_POLYTOPES, &ctRecv, DM_NUM_POLYTOPES, &ctShift, DM_NUM_POLYTOPES, &ctIdx));
905:   for (p = 0; p < nleaves; ++p) {
906:     if (remoteDepths[p].rank < 0) {
907:       ++depthRecv[remoteDepths[p].index];
908:     } else {
909:       ++ctRecv[remoteDepths[p].rank];
910:     }
911:   }
912:   {
913:     PetscInt depths[4], dims[4], shift = 0, i, c;

915:     /* Cells (depth), Vertices (0), Faces (depth-1), Edges (1)
916:          Consider DM_POLYTOPE_FV_GHOST, DM_POLYTOPE_INTERIOR_GHOST and DM_POLYTOPE_UNKNOWN_CELL as cells
917:      */
918:     depths[0] = depth;
919:     depths[1] = 0;
920:     depths[2] = depth - 1;
921:     depths[3] = 1;
922:     dims[0]   = dim;
923:     dims[1]   = 0;
924:     dims[2]   = dim - 1;
925:     dims[3]   = 1;
926:     for (i = 0; i <= depth; ++i) {
927:       const PetscInt dep = depths[i];
928:       const PetscInt dim = dims[i];

930:       for (c = 0; c < DM_NUM_POLYTOPES; ++c) {
931:         if (DMPolytopeTypeGetDim((DMPolytopeType)c) != dim && !(i == 0 && (c == DM_POLYTOPE_FV_GHOST || c == DM_POLYTOPE_INTERIOR_GHOST || c == DM_POLYTOPE_UNKNOWN_CELL))) continue;
932:         ctShift[c] = shift;
933:         shift += ctRecv[c];
934:       }
935:       depthShift[dep] = shift;
936:       shift += depthRecv[dep];
937:     }
938:     for (c = 0; c < DM_NUM_POLYTOPES; ++c) {
939:       const PetscInt ctDim = DMPolytopeTypeGetDim((DMPolytopeType)c);

941:       if ((ctDim < 0 || ctDim > dim) && (c != DM_POLYTOPE_FV_GHOST && c != DM_POLYTOPE_INTERIOR_GHOST && c != DM_POLYTOPE_UNKNOWN_CELL)) {
942:         ctShift[c] = shift;
943:         shift += ctRecv[c];
944:       }
945:     }
946:   }
947:   /* Derive a new local permutation based on stratified indices */
948:   PetscCall(PetscMalloc1(nleaves, &ilocal));
949:   for (p = 0; p < nleaves; ++p) {
950:     const DMPolytopeType ct = (DMPolytopeType)remoteDepths[p].rank;

952:     ilocal[p] = ctShift[ct] + ctIdx[ct];
953:     ++ctIdx[ct];
954:   }
955:   PetscCall(PetscSFCreate(comm, migrationSF));
956:   PetscCall(PetscObjectSetName((PetscObject)*migrationSF, "Migration SF"));
957:   PetscCall(PetscSFSetGraph(*migrationSF, nroots, nleaves, ilocal, PETSC_OWN_POINTER, (PetscSFNode *)iremote, PETSC_COPY_VALUES));
958:   PetscCall(PetscFree2(pointDepths, remoteDepths));
959:   PetscCall(PetscFree6(depthRecv, depthShift, depthIdx, ctRecv, ctShift, ctIdx));
960:   PetscCall(PetscLogEventEnd(DMPLEX_PartStratSF, dm, 0, 0, 0));
961:   PetscFunctionReturn(PETSC_SUCCESS);
962: }

964: /*@
965:   DMPlexDistributeField - Distribute field data to match a given `PetscSF`, usually the `PetscSF` from mesh distribution

967:   Collective

969:   Input Parameters:
970: + dm              - The `DMPLEX` object
971: . pointSF         - The `PetscSF` describing the communication pattern
972: . originalSection - The `PetscSection` for existing data layout
973: - originalVec     - The existing data in a local vector

975:   Output Parameters:
976: + newSection - The `PetscSF` describing the new data layout
977: - newVec     - The new data in a local vector

979:   Level: developer

981: .seealso: `DMPLEX`, `DMPlexDistribute()`, `DMPlexDistributeFieldIS()`, `DMPlexDistributeData()`
982: @*/
983: PetscErrorCode DMPlexDistributeField(DM dm, PetscSF pointSF, PetscSection originalSection, Vec originalVec, PetscSection newSection, Vec newVec)
984: {
985:   PetscSF      fieldSF;
986:   PetscInt    *remoteOffsets, fieldSize;
987:   PetscScalar *originalValues, *newValues;

989:   PetscFunctionBegin;
990:   PetscCall(PetscLogEventBegin(DMPLEX_DistributeField, dm, 0, 0, 0));
991:   PetscCall(PetscSFDistributeSection(pointSF, originalSection, &remoteOffsets, newSection));

993:   PetscCall(PetscSectionGetStorageSize(newSection, &fieldSize));
994:   PetscCall(VecSetSizes(newVec, fieldSize, PETSC_DETERMINE));
995:   PetscCall(VecSetType(newVec, dm->vectype));

997:   PetscCall(VecGetArray(originalVec, &originalValues));
998:   PetscCall(VecGetArray(newVec, &newValues));
999:   PetscCall(PetscSFCreateSectionSF(pointSF, originalSection, remoteOffsets, newSection, &fieldSF));
1000:   PetscCall(PetscFree(remoteOffsets));
1001:   PetscCall(PetscSFBcastBegin(fieldSF, MPIU_SCALAR, originalValues, newValues, MPI_REPLACE));
1002:   PetscCall(PetscSFBcastEnd(fieldSF, MPIU_SCALAR, originalValues, newValues, MPI_REPLACE));
1003:   PetscCall(PetscSFDestroy(&fieldSF));
1004:   PetscCall(VecRestoreArray(newVec, &newValues));
1005:   PetscCall(VecRestoreArray(originalVec, &originalValues));
1006:   PetscCall(PetscLogEventEnd(DMPLEX_DistributeField, dm, 0, 0, 0));
1007:   PetscFunctionReturn(PETSC_SUCCESS);
1008: }

1010: /*@
1011:   DMPlexDistributeFieldIS - Distribute field data to match a given `PetscSF`, usually the `PetscSF` from mesh distribution

1013:   Collective

1015:   Input Parameters:
1016: + dm              - The `DMPLEX` object
1017: . pointSF         - The `PetscSF` describing the communication pattern
1018: . originalSection - The `PetscSection` for existing data layout
1019: - originalIS      - The existing data

1021:   Output Parameters:
1022: + newSection - The `PetscSF` describing the new data layout
1023: - newIS      - The new data

1025:   Level: developer

1027: .seealso: `DMPLEX`, `DMPlexDistribute()`, `DMPlexDistributeField()`, `DMPlexDistributeData()`
1028: @*/
1029: PetscErrorCode DMPlexDistributeFieldIS(DM dm, PetscSF pointSF, PetscSection originalSection, IS originalIS, PetscSection newSection, IS *newIS)
1030: {
1031:   PetscSF         fieldSF;
1032:   PetscInt       *newValues, *remoteOffsets, fieldSize;
1033:   const PetscInt *originalValues;

1035:   PetscFunctionBegin;
1036:   PetscCall(PetscLogEventBegin(DMPLEX_DistributeField, dm, 0, 0, 0));
1037:   PetscCall(PetscSFDistributeSection(pointSF, originalSection, &remoteOffsets, newSection));

1039:   PetscCall(PetscSectionGetStorageSize(newSection, &fieldSize));
1040:   PetscCall(PetscMalloc1(fieldSize, &newValues));

1042:   PetscCall(ISGetIndices(originalIS, &originalValues));
1043:   PetscCall(PetscSFCreateSectionSF(pointSF, originalSection, remoteOffsets, newSection, &fieldSF));
1044:   PetscCall(PetscFree(remoteOffsets));
1045:   PetscCall(PetscSFBcastBegin(fieldSF, MPIU_INT, (PetscInt *)originalValues, newValues, MPI_REPLACE));
1046:   PetscCall(PetscSFBcastEnd(fieldSF, MPIU_INT, (PetscInt *)originalValues, newValues, MPI_REPLACE));
1047:   PetscCall(PetscSFDestroy(&fieldSF));
1048:   PetscCall(ISRestoreIndices(originalIS, &originalValues));
1049:   PetscCall(ISCreateGeneral(PetscObjectComm((PetscObject)pointSF), fieldSize, newValues, PETSC_OWN_POINTER, newIS));
1050:   PetscCall(PetscLogEventEnd(DMPLEX_DistributeField, dm, 0, 0, 0));
1051:   PetscFunctionReturn(PETSC_SUCCESS);
1052: }

1054: /*@
1055:   DMPlexDistributeData - Distribute field data to match a given `PetscSF`, usually the `PetscSF` from mesh distribution

1057:   Collective

1059:   Input Parameters:
1060: + dm              - The `DMPLEX` object
1061: . pointSF         - The `PetscSF` describing the communication pattern
1062: . originalSection - The `PetscSection` for existing data layout
1063: . datatype        - The type of data
1064: - originalData    - The existing data

1066:   Output Parameters:
1067: + newSection - The `PetscSection` describing the new data layout
1068: - newData    - The new data

1070:   Level: developer

1072: .seealso: `DMPLEX`, `DMPlexDistribute()`, `DMPlexDistributeField()`
1073: @*/
1074: PetscErrorCode DMPlexDistributeData(DM dm, PetscSF pointSF, PetscSection originalSection, MPI_Datatype datatype, void *originalData, PetscSection newSection, void **newData)
1075: {
1076:   PetscSF     fieldSF;
1077:   PetscInt   *remoteOffsets, fieldSize;
1078:   PetscMPIInt dataSize;

1080:   PetscFunctionBegin;
1081:   PetscCall(PetscLogEventBegin(DMPLEX_DistributeData, dm, 0, 0, 0));
1082:   PetscCall(PetscSFDistributeSection(pointSF, originalSection, &remoteOffsets, newSection));

1084:   PetscCall(PetscSectionGetStorageSize(newSection, &fieldSize));
1085:   PetscCallMPI(MPI_Type_size(datatype, &dataSize));
1086:   PetscCall(PetscMalloc(fieldSize * dataSize, newData));

1088:   PetscCall(PetscSFCreateSectionSF(pointSF, originalSection, remoteOffsets, newSection, &fieldSF));
1089:   PetscCall(PetscFree(remoteOffsets));
1090:   PetscCall(PetscSFBcastBegin(fieldSF, datatype, originalData, *newData, MPI_REPLACE));
1091:   PetscCall(PetscSFBcastEnd(fieldSF, datatype, originalData, *newData, MPI_REPLACE));
1092:   PetscCall(PetscSFDestroy(&fieldSF));
1093:   PetscCall(PetscLogEventEnd(DMPLEX_DistributeData, dm, 0, 0, 0));
1094:   PetscFunctionReturn(PETSC_SUCCESS);
1095: }

1097: static PetscErrorCode DMPlexDistributeCones(DM dm, PetscSF migrationSF, ISLocalToGlobalMapping original, ISLocalToGlobalMapping renumbering, DM dmParallel)
1098: {
1099:   DM_Plex     *pmesh = (DM_Plex *)dmParallel->data;
1100:   MPI_Comm     comm;
1101:   PetscSF      coneSF;
1102:   PetscSection originalConeSection, newConeSection;
1103:   PetscInt    *remoteOffsets, *cones, *globCones, *newCones, newConesSize;
1104:   PetscBool    flg;

1106:   PetscFunctionBegin;
1109:   PetscCall(PetscLogEventBegin(DMPLEX_DistributeCones, dm, 0, 0, 0));
1110:   /* Distribute cone section */
1111:   PetscCall(PetscObjectGetComm((PetscObject)dm, &comm));
1112:   PetscCall(DMPlexGetConeSection(dm, &originalConeSection));
1113:   PetscCall(DMPlexGetConeSection(dmParallel, &newConeSection));
1114:   PetscCall(PetscSFDistributeSection(migrationSF, originalConeSection, &remoteOffsets, newConeSection));
1115:   PetscCall(DMSetUp(dmParallel));
1116:   /* Communicate and renumber cones */
1117:   PetscCall(PetscSFCreateSectionSF(migrationSF, originalConeSection, remoteOffsets, newConeSection, &coneSF));
1118:   PetscCall(PetscFree(remoteOffsets));
1119:   PetscCall(DMPlexGetCones(dm, &cones));
1120:   if (original) {
1121:     PetscInt numCones;

1123:     PetscCall(PetscSectionGetStorageSize(originalConeSection, &numCones));
1124:     PetscCall(PetscMalloc1(numCones, &globCones));
1125:     PetscCall(ISLocalToGlobalMappingApplyBlock(original, numCones, cones, globCones));
1126:   } else {
1127:     globCones = cones;
1128:   }
1129:   PetscCall(DMPlexGetCones(dmParallel, &newCones));
1130:   PetscCall(PetscSFBcastBegin(coneSF, MPIU_INT, globCones, newCones, MPI_REPLACE));
1131:   PetscCall(PetscSFBcastEnd(coneSF, MPIU_INT, globCones, newCones, MPI_REPLACE));
1132:   if (original) PetscCall(PetscFree(globCones));
1133:   PetscCall(PetscSectionGetStorageSize(newConeSection, &newConesSize));
1134:   PetscCall(ISGlobalToLocalMappingApplyBlock(renumbering, IS_GTOLM_MASK, newConesSize, newCones, NULL, newCones));
1135:   if (PetscDefined(USE_DEBUG)) {
1136:     PetscInt  p;
1137:     PetscBool valid = PETSC_TRUE;
1138:     for (p = 0; p < newConesSize; ++p) {
1139:       if (newCones[p] < 0) {
1140:         valid = PETSC_FALSE;
1141:         PetscCall(PetscPrintf(PETSC_COMM_SELF, "[%d] Point %" PetscInt_FMT " not in overlap SF\n", PetscGlobalRank, p));
1142:       }
1143:     }
1144:     PetscCheck(valid, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Invalid global to local map");
1145:   }
1146:   PetscCall(PetscOptionsHasName(((PetscObject)dm)->options, ((PetscObject)dm)->prefix, "-cones_view", &flg));
1147:   if (flg) {
1148:     PetscCall(PetscPrintf(comm, "Serial Cone Section:\n"));
1149:     PetscCall(PetscSectionView(originalConeSection, PETSC_VIEWER_STDOUT_(comm)));
1150:     PetscCall(PetscPrintf(comm, "Parallel Cone Section:\n"));
1151:     PetscCall(PetscSectionView(newConeSection, PETSC_VIEWER_STDOUT_(comm)));
1152:     PetscCall(PetscSFView(coneSF, NULL));
1153:   }
1154:   PetscCall(DMPlexGetConeOrientations(dm, &cones));
1155:   PetscCall(DMPlexGetConeOrientations(dmParallel, &newCones));
1156:   PetscCall(PetscSFBcastBegin(coneSF, MPIU_INT, cones, newCones, MPI_REPLACE));
1157:   PetscCall(PetscSFBcastEnd(coneSF, MPIU_INT, cones, newCones, MPI_REPLACE));
1158:   PetscCall(PetscSFDestroy(&coneSF));
1159:   PetscCall(PetscLogEventEnd(DMPLEX_DistributeCones, dm, 0, 0, 0));
1160:   /* Create supports and stratify DMPlex */
1161:   {
1162:     PetscInt pStart, pEnd;

1164:     PetscCall(PetscSectionGetChart(pmesh->coneSection, &pStart, &pEnd));
1165:     PetscCall(PetscSectionSetChart(pmesh->supportSection, pStart, pEnd));
1166:   }
1167:   PetscCall(DMPlexSymmetrize(dmParallel));
1168:   PetscCall(DMPlexStratify(dmParallel));
1169:   {
1170:     PetscBool useCone, useClosure, useAnchors;

1172:     PetscCall(DMGetBasicAdjacency(dm, &useCone, &useClosure));
1173:     PetscCall(DMSetBasicAdjacency(dmParallel, useCone, useClosure));
1174:     PetscCall(DMPlexGetAdjacencyUseAnchors(dm, &useAnchors));
1175:     PetscCall(DMPlexSetAdjacencyUseAnchors(dmParallel, useAnchors));
1176:   }
1177:   PetscFunctionReturn(PETSC_SUCCESS);
1178: }

1180: static PetscErrorCode DMPlexDistributeCoordinates(DM dm, PetscSF migrationSF, DM dmParallel)
1181: {
1182:   MPI_Comm         comm;
1183:   DM               cdm, cdmParallel;
1184:   PetscSection     originalCoordSection, newCoordSection;
1185:   Vec              originalCoordinates, newCoordinates;
1186:   PetscInt         bs;
1187:   const char      *name;
1188:   const PetscReal *maxCell, *Lstart, *L;

1190:   PetscFunctionBegin;

1194:   PetscCall(PetscObjectGetComm((PetscObject)dm, &comm));
1195:   PetscCall(DMGetCoordinateDM(dm, &cdm));
1196:   PetscCall(DMGetCoordinateDM(dmParallel, &cdmParallel));
1197:   PetscCall(DMCopyDisc(cdm, cdmParallel));
1198:   PetscCall(DMGetCoordinateSection(dm, &originalCoordSection));
1199:   PetscCall(DMGetCoordinateSection(dmParallel, &newCoordSection));
1200:   PetscCall(DMGetCoordinatesLocal(dm, &originalCoordinates));
1201:   if (originalCoordinates) {
1202:     PetscCall(VecCreate(PETSC_COMM_SELF, &newCoordinates));
1203:     PetscCall(PetscObjectGetName((PetscObject)originalCoordinates, &name));
1204:     PetscCall(PetscObjectSetName((PetscObject)newCoordinates, name));

1206:     PetscCall(DMPlexDistributeField(dm, migrationSF, originalCoordSection, originalCoordinates, newCoordSection, newCoordinates));
1207:     PetscCall(DMSetCoordinatesLocal(dmParallel, newCoordinates));
1208:     PetscCall(VecGetBlockSize(originalCoordinates, &bs));
1209:     PetscCall(VecSetBlockSize(newCoordinates, bs));
1210:     PetscCall(VecDestroy(&newCoordinates));
1211:   }

1213:   PetscCall(PetscObjectGetComm((PetscObject)dm, &comm));
1214:   PetscCall(DMGetPeriodicity(dm, &maxCell, &Lstart, &L));
1215:   PetscCall(DMSetPeriodicity(dmParallel, maxCell, Lstart, L));
1216:   PetscCall(DMGetCellCoordinateDM(dm, &cdm));
1217:   if (cdm) {
1218:     PetscCall(DMClone(dmParallel, &cdmParallel));
1219:     PetscCall(DMSetCellCoordinateDM(dmParallel, cdmParallel));
1220:     PetscCall(DMCopyDisc(cdm, cdmParallel));
1221:     PetscCall(DMDestroy(&cdmParallel));
1222:     PetscCall(DMGetCellCoordinateSection(dm, &originalCoordSection));
1223:     PetscCall(DMGetCellCoordinatesLocal(dm, &originalCoordinates));
1224:     PetscCall(PetscSectionCreate(comm, &newCoordSection));
1225:     if (originalCoordinates) {
1226:       PetscCall(VecCreate(PETSC_COMM_SELF, &newCoordinates));
1227:       PetscCall(PetscObjectGetName((PetscObject)originalCoordinates, &name));
1228:       PetscCall(PetscObjectSetName((PetscObject)newCoordinates, name));

1230:       PetscCall(DMPlexDistributeField(dm, migrationSF, originalCoordSection, originalCoordinates, newCoordSection, newCoordinates));
1231:       PetscCall(VecGetBlockSize(originalCoordinates, &bs));
1232:       PetscCall(VecSetBlockSize(newCoordinates, bs));
1233:       PetscCall(DMSetCellCoordinateSection(dmParallel, bs, newCoordSection));
1234:       PetscCall(DMSetCellCoordinatesLocal(dmParallel, newCoordinates));
1235:       PetscCall(VecDestroy(&newCoordinates));
1236:     }
1237:     PetscCall(PetscSectionDestroy(&newCoordSection));
1238:   }
1239:   PetscFunctionReturn(PETSC_SUCCESS);
1240: }

1242: static PetscErrorCode DMPlexDistributeLabels(DM dm, PetscSF migrationSF, DM dmParallel)
1243: {
1244:   DM_Plex         *mesh = (DM_Plex *)dm->data;
1245:   MPI_Comm         comm;
1246:   DMLabel          depthLabel;
1247:   PetscMPIInt      rank;
1248:   PetscInt         depth, d, numLabels, numLocalLabels, l;
1249:   PetscBool        hasLabels  = PETSC_FALSE, lsendDepth, sendDepth;
1250:   PetscObjectState depthState = -1;

1252:   PetscFunctionBegin;

1256:   PetscCall(PetscLogEventBegin(DMPLEX_DistributeLabels, dm, 0, 0, 0));
1257:   PetscCall(PetscObjectGetComm((PetscObject)dm, &comm));
1258:   PetscCallMPI(MPI_Comm_rank(comm, &rank));

1260:   /* If the user has changed the depth label, communicate it instead */
1261:   PetscCall(DMPlexGetDepth(dm, &depth));
1262:   PetscCall(DMPlexGetDepthLabel(dm, &depthLabel));
1263:   if (depthLabel) PetscCall(PetscObjectStateGet((PetscObject)depthLabel, &depthState));
1264:   lsendDepth = mesh->depthState != depthState ? PETSC_TRUE : PETSC_FALSE;
1265:   PetscCallMPI(MPIU_Allreduce(&lsendDepth, &sendDepth, 1, MPIU_BOOL, MPI_LOR, comm));
1266:   if (sendDepth) {
1267:     PetscCall(DMPlexGetDepthLabel(dmParallel, &dmParallel->depthLabel));
1268:     PetscCall(DMRemoveLabelBySelf(dmParallel, &dmParallel->depthLabel, PETSC_FALSE));
1269:   }
1270:   /* Everyone must have either the same number of labels, or none */
1271:   PetscCall(DMGetNumLabels(dm, &numLocalLabels));
1272:   numLabels = numLocalLabels;
1273:   PetscCallMPI(MPI_Bcast(&numLabels, 1, MPIU_INT, 0, comm));
1274:   if (numLabels == numLocalLabels) hasLabels = PETSC_TRUE;
1275:   for (l = 0; l < numLabels; ++l) {
1276:     DMLabel     label = NULL, labelNew = NULL;
1277:     PetscBool   isDepth, lisOutput     = PETSC_TRUE, isOutput;
1278:     const char *name = NULL;

1280:     if (hasLabels) {
1281:       PetscCall(DMGetLabelByNum(dm, l, &label));
1282:       /* Skip "depth" because it is recreated */
1283:       PetscCall(PetscObjectGetName((PetscObject)label, &name));
1284:       PetscCall(PetscStrcmp(name, "depth", &isDepth));
1285:     } else {
1286:       isDepth = PETSC_FALSE;
1287:     }
1288:     PetscCallMPI(MPI_Bcast(&isDepth, 1, MPIU_BOOL, 0, comm));
1289:     if (isDepth && !sendDepth) continue;
1290:     PetscCall(DMLabelDistribute(label, migrationSF, &labelNew));
1291:     if (isDepth) {
1292:       /* Put in any missing strata which can occur if users are managing the depth label themselves */
1293:       PetscInt gdepth;

1295:       PetscCallMPI(MPIU_Allreduce(&depth, &gdepth, 1, MPIU_INT, MPI_MAX, comm));
1296:       PetscCheck(!(depth >= 0) || !(gdepth != depth), PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Inconsistent Plex depth %" PetscInt_FMT " != %" PetscInt_FMT, depth, gdepth);
1297:       for (d = 0; d <= gdepth; ++d) {
1298:         PetscBool has;

1300:         PetscCall(DMLabelHasStratum(labelNew, d, &has));
1301:         if (!has) PetscCall(DMLabelAddStratum(labelNew, d));
1302:       }
1303:     }
1304:     PetscCall(DMAddLabel(dmParallel, labelNew));
1305:     /* Put the output flag in the new label */
1306:     if (hasLabels) PetscCall(DMGetLabelOutput(dm, name, &lisOutput));
1307:     PetscCallMPI(MPIU_Allreduce(&lisOutput, &isOutput, 1, MPIU_BOOL, MPI_LAND, comm));
1308:     PetscCall(PetscObjectGetName((PetscObject)labelNew, &name));
1309:     PetscCall(DMSetLabelOutput(dmParallel, name, isOutput));
1310:     PetscCall(DMLabelDestroy(&labelNew));
1311:   }
1312:   {
1313:     DMLabel ctLabel;

1315:     // Reset label for fast lookup
1316:     PetscCall(DMPlexGetCellTypeLabel(dmParallel, &ctLabel));
1317:     PetscCall(DMLabelMakeAllInvalid_Internal(ctLabel));
1318:   }
1319:   PetscCall(PetscLogEventEnd(DMPLEX_DistributeLabels, dm, 0, 0, 0));
1320:   PetscFunctionReturn(PETSC_SUCCESS);
1321: }

1323: static PetscErrorCode DMPlexDistributeSetupTree(DM dm, PetscSF migrationSF, ISLocalToGlobalMapping original, ISLocalToGlobalMapping renumbering, DM dmParallel)
1324: {
1325:   DM_Plex     *mesh  = (DM_Plex *)dm->data;
1326:   DM_Plex     *pmesh = (DM_Plex *)dmParallel->data;
1327:   MPI_Comm     comm;
1328:   DM           refTree;
1329:   PetscSection origParentSection, newParentSection;
1330:   PetscInt    *origParents, *origChildIDs;
1331:   PetscBool    flg;

1333:   PetscFunctionBegin;
1336:   PetscCall(PetscObjectGetComm((PetscObject)dm, &comm));

1338:   /* Set up tree */
1339:   PetscCall(DMPlexGetReferenceTree(dm, &refTree));
1340:   PetscCall(DMPlexSetReferenceTree(dmParallel, refTree));
1341:   PetscCall(DMPlexGetTree(dm, &origParentSection, &origParents, &origChildIDs, NULL, NULL));
1342:   if (origParentSection) {
1343:     PetscInt  pStart, pEnd;
1344:     PetscInt *newParents, *newChildIDs, *globParents;
1345:     PetscInt *remoteOffsetsParents, newParentSize;
1346:     PetscSF   parentSF;

1348:     PetscCall(DMPlexGetChart(dmParallel, &pStart, &pEnd));
1349:     PetscCall(PetscSectionCreate(PetscObjectComm((PetscObject)dmParallel), &newParentSection));
1350:     PetscCall(PetscSectionSetChart(newParentSection, pStart, pEnd));
1351:     PetscCall(PetscSFDistributeSection(migrationSF, origParentSection, &remoteOffsetsParents, newParentSection));
1352:     PetscCall(PetscSFCreateSectionSF(migrationSF, origParentSection, remoteOffsetsParents, newParentSection, &parentSF));
1353:     PetscCall(PetscFree(remoteOffsetsParents));
1354:     PetscCall(PetscSectionGetStorageSize(newParentSection, &newParentSize));
1355:     PetscCall(PetscMalloc2(newParentSize, &newParents, newParentSize, &newChildIDs));
1356:     if (original) {
1357:       PetscInt numParents;

1359:       PetscCall(PetscSectionGetStorageSize(origParentSection, &numParents));
1360:       PetscCall(PetscMalloc1(numParents, &globParents));
1361:       PetscCall(ISLocalToGlobalMappingApplyBlock(original, numParents, origParents, globParents));
1362:     } else {
1363:       globParents = origParents;
1364:     }
1365:     PetscCall(PetscSFBcastBegin(parentSF, MPIU_INT, globParents, newParents, MPI_REPLACE));
1366:     PetscCall(PetscSFBcastEnd(parentSF, MPIU_INT, globParents, newParents, MPI_REPLACE));
1367:     if (original) PetscCall(PetscFree(globParents));
1368:     PetscCall(PetscSFBcastBegin(parentSF, MPIU_INT, origChildIDs, newChildIDs, MPI_REPLACE));
1369:     PetscCall(PetscSFBcastEnd(parentSF, MPIU_INT, origChildIDs, newChildIDs, MPI_REPLACE));
1370:     PetscCall(ISGlobalToLocalMappingApplyBlock(renumbering, IS_GTOLM_MASK, newParentSize, newParents, NULL, newParents));
1371:     if (PetscDefined(USE_DEBUG)) {
1372:       PetscInt  p;
1373:       PetscBool valid = PETSC_TRUE;
1374:       for (p = 0; p < newParentSize; ++p) {
1375:         if (newParents[p] < 0) {
1376:           valid = PETSC_FALSE;
1377:           PetscCall(PetscPrintf(PETSC_COMM_SELF, "Point %" PetscInt_FMT " not in overlap SF\n", p));
1378:         }
1379:       }
1380:       PetscCheck(valid, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Invalid global to local map");
1381:     }
1382:     PetscCall(PetscOptionsHasName(((PetscObject)dm)->options, ((PetscObject)dm)->prefix, "-parents_view", &flg));
1383:     if (flg) {
1384:       PetscCall(PetscPrintf(comm, "Serial Parent Section: \n"));
1385:       PetscCall(PetscSectionView(origParentSection, PETSC_VIEWER_STDOUT_(comm)));
1386:       PetscCall(PetscPrintf(comm, "Parallel Parent Section: \n"));
1387:       PetscCall(PetscSectionView(newParentSection, PETSC_VIEWER_STDOUT_(comm)));
1388:       PetscCall(PetscSFView(parentSF, NULL));
1389:     }
1390:     PetscCall(DMPlexSetTree(dmParallel, newParentSection, newParents, newChildIDs));
1391:     PetscCall(PetscSectionDestroy(&newParentSection));
1392:     PetscCall(PetscFree2(newParents, newChildIDs));
1393:     PetscCall(PetscSFDestroy(&parentSF));
1394:   }
1395:   pmesh->useAnchors = mesh->useAnchors;
1396:   PetscFunctionReturn(PETSC_SUCCESS);
1397: }

1399: /*@
1400:   DMPlexSetPartitionBalance - Should distribution of the `DM` attempt to balance the shared point partition?

1402:   Input Parameters:
1403: + dm  - The `DMPLEX` object
1404: - flg - Balance the partition?

1406:   Level: intermediate

1408: .seealso: `DMPLEX`, `DMPlexDistribute()`, `DMPlexGetPartitionBalance()`
1409: @*/
1410: PetscErrorCode DMPlexSetPartitionBalance(DM dm, PetscBool flg)
1411: {
1412:   DM_Plex *mesh = (DM_Plex *)dm->data;

1414:   PetscFunctionBegin;
1415:   mesh->partitionBalance = flg;
1416:   PetscFunctionReturn(PETSC_SUCCESS);
1417: }

1419: /*@
1420:   DMPlexGetPartitionBalance - Does distribution of the `DM` attempt to balance the shared point partition?

1422:   Input Parameter:
1423: . dm - The `DMPLEX` object

1425:   Output Parameter:
1426: . flg - Balance the partition?

1428:   Level: intermediate

1430: .seealso: `DMPLEX`, `DMPlexDistribute()`, `DMPlexSetPartitionBalance()`
1431: @*/
1432: PetscErrorCode DMPlexGetPartitionBalance(DM dm, PetscBool *flg)
1433: {
1434:   DM_Plex *mesh = (DM_Plex *)dm->data;

1436:   PetscFunctionBegin;
1438:   PetscAssertPointer(flg, 2);
1439:   *flg = mesh->partitionBalance;
1440:   PetscFunctionReturn(PETSC_SUCCESS);
1441: }

1443: typedef struct {
1444:   PetscInt vote, rank, index;
1445: } Petsc3Int;

1447: /* MaxLoc, but carry a third piece of information around */
1448: static void MPIAPI MaxLocCarry(void *in_, void *inout_, PetscMPIInt *len_, MPI_Datatype *dtype)
1449: {
1450:   Petsc3Int *a = (Petsc3Int *)inout_;
1451:   Petsc3Int *b = (Petsc3Int *)in_;
1452:   PetscInt   i, len = *len_;
1453:   for (i = 0; i < len; i++) {
1454:     if (a[i].vote < b[i].vote) {
1455:       a[i].vote  = b[i].vote;
1456:       a[i].rank  = b[i].rank;
1457:       a[i].index = b[i].index;
1458:     } else if (a[i].vote <= b[i].vote) {
1459:       if (a[i].rank >= b[i].rank) {
1460:         a[i].rank  = b[i].rank;
1461:         a[i].index = b[i].index;
1462:       }
1463:     }
1464:   }
1465: }

1467: /*@
1468:   DMPlexCreatePointSF - Build a point `PetscSF` from an `PetscSF` describing a point migration

1470:   Input Parameters:
1471: + dm          - The source `DMPLEX` object
1472: . migrationSF - The star forest that describes the parallel point remapping
1473: - ownership   - Flag causing a vote to determine point ownership

1475:   Output Parameter:
1476: . pointSF - The star forest describing the point overlap in the remapped `DM`

1478:   Level: developer

1480:   Note:
1481:   Output `pointSF` is guaranteed to have the array of local indices (leaves) sorted.

1483: .seealso: `DMPLEX`, `PetscSF`, `DM`, `DMPlexDistribute()`, `DMPlexDistributeOverlap()`
1484: @*/
1485: PetscErrorCode DMPlexCreatePointSF(DM dm, PetscSF migrationSF, PetscBool ownership, PetscSF *pointSF)
1486: {
1487:   PetscMPIInt        rank, size;
1488:   PetscInt           p, nroots, nleaves, idx, npointLeaves;
1489:   PetscInt          *pointLocal;
1490:   const PetscInt    *leaves;
1491:   const PetscSFNode *roots;
1492:   PetscSFNode       *rootNodes, *leafNodes, *pointRemote;
1493:   Vec                shifts;
1494:   const PetscInt     numShifts  = 13759;
1495:   const PetscScalar *shift      = NULL;
1496:   const PetscBool    shiftDebug = PETSC_FALSE;
1497:   PetscBool          balance;

1499:   PetscFunctionBegin;
1501:   PetscCallMPI(MPI_Comm_rank(PetscObjectComm((PetscObject)dm), &rank));
1502:   PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)dm), &size));
1503:   PetscCall(PetscLogEventBegin(DMPLEX_CreatePointSF, dm, 0, 0, 0));
1504:   PetscCall(PetscSFCreate(PetscObjectComm((PetscObject)dm), pointSF));
1505:   PetscCall(PetscSFSetFromOptions(*pointSF));
1506:   if (size == 1) PetscFunctionReturn(PETSC_SUCCESS);

1508:   PetscCall(DMPlexGetPartitionBalance(dm, &balance));
1509:   PetscCall(PetscSFGetGraph(migrationSF, &nroots, &nleaves, &leaves, &roots));
1510:   PetscCall(PetscMalloc2(nroots, &rootNodes, nleaves, &leafNodes));
1511:   if (ownership) {
1512:     MPI_Op       op;
1513:     MPI_Datatype datatype;
1514:     Petsc3Int   *rootVote = NULL, *leafVote = NULL;

1516:     /* If balancing, we compute a random cyclic shift of the rank for each remote point. That way, the max will evenly distribute among ranks. */
1517:     if (balance) {
1518:       PetscRandom r;

1520:       PetscCall(PetscRandomCreate(PETSC_COMM_SELF, &r));
1521:       PetscCall(PetscRandomSetInterval(r, 0, 2467 * size));
1522:       PetscCall(VecCreate(PETSC_COMM_SELF, &shifts));
1523:       PetscCall(VecSetSizes(shifts, numShifts, numShifts));
1524:       PetscCall(VecSetType(shifts, VECSTANDARD));
1525:       PetscCall(VecSetRandom(shifts, r));
1526:       PetscCall(PetscRandomDestroy(&r));
1527:       PetscCall(VecGetArrayRead(shifts, &shift));
1528:     }

1530:     PetscCall(PetscMalloc1(nroots, &rootVote));
1531:     PetscCall(PetscMalloc1(nleaves, &leafVote));
1532:     /* Point ownership vote: Process with highest rank owns shared points */
1533:     for (p = 0; p < nleaves; ++p) {
1534:       if (shiftDebug) {
1535:         PetscCall(PetscSynchronizedPrintf(PetscObjectComm((PetscObject)dm), "[%d] Point %" PetscInt_FMT " RemotePoint %" PetscInt_FMT " Shift %" PetscInt_FMT " MyRank %" PetscInt_FMT "\n", rank, leaves ? leaves[p] : p, roots[p].index,
1536:                                           (PetscInt)PetscRealPart(shift[roots[p].index % numShifts]), (rank + (shift ? (PetscInt)PetscRealPart(shift[roots[p].index % numShifts]) : 0)) % size));
1537:       }
1538:       /* Either put in a bid or we know we own it */
1539:       leafVote[p].vote  = (rank + (shift ? (PetscInt)PetscRealPart(shift[roots[p].index % numShifts]) : 0)) % size;
1540:       leafVote[p].rank  = rank;
1541:       leafVote[p].index = p;
1542:     }
1543:     for (p = 0; p < nroots; p++) {
1544:       /* Root must not participate in the reduction, flag so that MAXLOC does not use */
1545:       rootVote[p].vote  = -3;
1546:       rootVote[p].rank  = -3;
1547:       rootVote[p].index = -3;
1548:     }
1549:     PetscCallMPI(MPI_Type_contiguous(3, MPIU_INT, &datatype));
1550:     PetscCallMPI(MPI_Type_commit(&datatype));
1551:     PetscCallMPI(MPI_Op_create(&MaxLocCarry, 1, &op));
1552:     PetscCall(PetscSFReduceBegin(migrationSF, datatype, leafVote, rootVote, op));
1553:     PetscCall(PetscSFReduceEnd(migrationSF, datatype, leafVote, rootVote, op));
1554:     PetscCallMPI(MPI_Op_free(&op));
1555:     PetscCallMPI(MPI_Type_free(&datatype));
1556:     for (p = 0; p < nroots; p++) {
1557:       rootNodes[p].rank  = rootVote[p].rank;
1558:       rootNodes[p].index = rootVote[p].index;
1559:     }
1560:     PetscCall(PetscFree(leafVote));
1561:     PetscCall(PetscFree(rootVote));
1562:   } else {
1563:     for (p = 0; p < nroots; p++) {
1564:       rootNodes[p].index = -1;
1565:       rootNodes[p].rank  = rank;
1566:     }
1567:     for (p = 0; p < nleaves; p++) {
1568:       /* Write new local id into old location */
1569:       if (roots[p].rank == rank) rootNodes[roots[p].index].index = leaves ? leaves[p] : p;
1570:     }
1571:   }
1572:   PetscCall(PetscSFBcastBegin(migrationSF, MPIU_SF_NODE, rootNodes, leafNodes, MPI_REPLACE));
1573:   PetscCall(PetscSFBcastEnd(migrationSF, MPIU_SF_NODE, rootNodes, leafNodes, MPI_REPLACE));

1575:   for (npointLeaves = 0, p = 0; p < nleaves; p++) {
1576:     if (leafNodes[p].rank != rank) npointLeaves++;
1577:   }
1578:   PetscCall(PetscMalloc1(npointLeaves, &pointLocal));
1579:   PetscCall(PetscMalloc1(npointLeaves, &pointRemote));
1580:   for (idx = 0, p = 0; p < nleaves; p++) {
1581:     if (leafNodes[p].rank != rank) {
1582:       /* Note that pointLocal is automatically sorted as it is sublist of 0, ..., nleaves-1 */
1583:       pointLocal[idx]  = p;
1584:       pointRemote[idx] = leafNodes[p];
1585:       idx++;
1586:     }
1587:   }
1588:   if (shift) {
1589:     PetscCall(VecRestoreArrayRead(shifts, &shift));
1590:     PetscCall(VecDestroy(&shifts));
1591:   }
1592:   if (shiftDebug) PetscCall(PetscSynchronizedFlush(PetscObjectComm((PetscObject)dm), PETSC_STDOUT));
1593:   PetscCall(PetscSFSetGraph(*pointSF, nleaves, npointLeaves, pointLocal, PETSC_OWN_POINTER, pointRemote, PETSC_OWN_POINTER));
1594:   PetscCall(PetscFree2(rootNodes, leafNodes));
1595:   PetscCall(PetscLogEventEnd(DMPLEX_CreatePointSF, dm, 0, 0, 0));
1596:   if (PetscDefined(USE_DEBUG)) PetscCall(DMPlexCheckPointSF(dm, *pointSF, PETSC_FALSE));
1597:   PetscFunctionReturn(PETSC_SUCCESS);
1598: }

1600: /*@
1601:   DMPlexMigrate  - Migrates internal `DM` data over the supplied star forest

1603:   Collective

1605:   Input Parameters:
1606: + dm - The source `DMPLEX` object
1607: - sf - The star forest communication context describing the migration pattern

1609:   Output Parameter:
1610: . targetDM - The target `DMPLEX` object

1612:   Level: intermediate

1614: .seealso: `DMPLEX`, `PetscSF`, `DM`, `DMPlexDistribute()`, `DMPlexDistributeOverlap()`
1615: @*/
1616: PetscErrorCode DMPlexMigrate(DM dm, PetscSF sf, DM targetDM)
1617: {
1618:   MPI_Comm               comm;
1619:   PetscInt               dim, cdim, nroots;
1620:   PetscSF                sfPoint;
1621:   ISLocalToGlobalMapping ltogMigration;
1622:   ISLocalToGlobalMapping ltogOriginal = NULL;

1624:   PetscFunctionBegin;
1626:   PetscCall(PetscLogEventBegin(DMPLEX_Migrate, dm, 0, 0, 0));
1627:   PetscCall(PetscObjectGetComm((PetscObject)dm, &comm));
1628:   PetscCall(DMGetDimension(dm, &dim));
1629:   PetscCall(DMSetDimension(targetDM, dim));
1630:   PetscCall(DMGetCoordinateDim(dm, &cdim));
1631:   PetscCall(DMSetCoordinateDim(targetDM, cdim));

1633:   /* Check for a one-to-all distribution pattern */
1634:   PetscCall(DMGetPointSF(dm, &sfPoint));
1635:   PetscCall(PetscSFGetGraph(sfPoint, &nroots, NULL, NULL, NULL));
1636:   if (nroots >= 0) {
1637:     IS        isOriginal;
1638:     PetscInt  n, size, nleaves;
1639:     PetscInt *numbering_orig, *numbering_new;

1641:     /* Get the original point numbering */
1642:     PetscCall(DMPlexCreatePointNumbering(dm, &isOriginal));
1643:     PetscCall(ISLocalToGlobalMappingCreateIS(isOriginal, &ltogOriginal));
1644:     PetscCall(ISLocalToGlobalMappingGetSize(ltogOriginal, &size));
1645:     PetscCall(ISLocalToGlobalMappingGetBlockIndices(ltogOriginal, (const PetscInt **)&numbering_orig));
1646:     /* Convert to positive global numbers */
1647:     for (n = 0; n < size; n++) {
1648:       if (numbering_orig[n] < 0) numbering_orig[n] = -(numbering_orig[n] + 1);
1649:     }
1650:     /* Derive the new local-to-global mapping from the old one */
1651:     PetscCall(PetscSFGetGraph(sf, NULL, &nleaves, NULL, NULL));
1652:     PetscCall(PetscMalloc1(nleaves, &numbering_new));
1653:     PetscCall(PetscSFBcastBegin(sf, MPIU_INT, numbering_orig, numbering_new, MPI_REPLACE));
1654:     PetscCall(PetscSFBcastEnd(sf, MPIU_INT, numbering_orig, numbering_new, MPI_REPLACE));
1655:     PetscCall(ISLocalToGlobalMappingCreate(comm, 1, nleaves, numbering_new, PETSC_OWN_POINTER, &ltogMigration));
1656:     PetscCall(ISLocalToGlobalMappingRestoreIndices(ltogOriginal, (const PetscInt **)&numbering_orig));
1657:     PetscCall(ISDestroy(&isOriginal));
1658:   } else {
1659:     /* One-to-all distribution pattern: We can derive LToG from SF */
1660:     PetscCall(ISLocalToGlobalMappingCreateSF(sf, 0, &ltogMigration));
1661:   }
1662:   PetscCall(PetscObjectSetName((PetscObject)ltogMigration, "Point renumbering for DM migration"));
1663:   PetscCall(ISLocalToGlobalMappingViewFromOptions(ltogMigration, (PetscObject)dm, "-partition_view"));
1664:   /* Migrate DM data to target DM */
1665:   PetscCall(DMPlexDistributeCones(dm, sf, ltogOriginal, ltogMigration, targetDM));
1666:   PetscCall(DMPlexDistributeLabels(dm, sf, targetDM));
1667:   PetscCall(DMPlexDistributeCoordinates(dm, sf, targetDM));
1668:   PetscCall(DMPlexDistributeSetupTree(dm, sf, ltogOriginal, ltogMigration, targetDM));
1669:   PetscCall(ISLocalToGlobalMappingDestroy(&ltogOriginal));
1670:   PetscCall(ISLocalToGlobalMappingDestroy(&ltogMigration));
1671:   PetscCall(PetscLogEventEnd(DMPLEX_Migrate, dm, 0, 0, 0));
1672:   PetscFunctionReturn(PETSC_SUCCESS);
1673: }

1675: /*@
1676:   DMPlexRemapMigrationSF - Rewrite the distribution SF to account for overlap

1678:   Collective

1680:   Input Parameters:
1681: + sfOverlap   - The `PetscSF` object just for the overlap
1682: - sfMigration - The original distribution `PetscSF` object

1684:   Output Parameters:
1685: . sfMigrationNew - A rewritten `PetscSF` object that incorporates the overlap

1687:   Level: developer

1689: .seealso: `DMPLEX`, `DM`, `DMPlexDistribute()`, `DMPlexDistributeOverlap()`, `DMPlexGetOverlap()`
1690: @*/
1691: PetscErrorCode DMPlexRemapMigrationSF(PetscSF sfOverlap, PetscSF sfMigration, PetscSF *sfMigrationNew)
1692: {
1693:   PetscSFNode       *newRemote, *permRemote = NULL;
1694:   const PetscInt    *oldLeaves;
1695:   const PetscSFNode *oldRemote;
1696:   PetscInt           nroots, nleaves, noldleaves;

1698:   PetscFunctionBegin;
1699:   PetscCall(PetscSFGetGraph(sfMigration, &nroots, &noldleaves, &oldLeaves, &oldRemote));
1700:   PetscCall(PetscSFGetGraph(sfOverlap, NULL, &nleaves, NULL, NULL));
1701:   PetscCall(PetscMalloc1(nleaves, &newRemote));
1702:   /* oldRemote: original root point mapping to original leaf point
1703:      newRemote: original leaf point mapping to overlapped leaf point */
1704:   if (oldLeaves) {
1705:     /* After stratification, the migration remotes may not be in root (canonical) order, so we reorder using the leaf numbering */
1706:     PetscCall(PetscMalloc1(noldleaves, &permRemote));
1707:     for (PetscInt l = 0; l < noldleaves; ++l) permRemote[oldLeaves[l]] = oldRemote[l];
1708:     oldRemote = permRemote;
1709:   }
1710:   PetscCall(PetscSFBcastBegin(sfOverlap, MPIU_SF_NODE, oldRemote, newRemote, MPI_REPLACE));
1711:   PetscCall(PetscSFBcastEnd(sfOverlap, MPIU_SF_NODE, oldRemote, newRemote, MPI_REPLACE));
1712:   PetscCall(PetscFree(permRemote));
1713:   PetscCall(PetscSFCreate(PetscObjectComm((PetscObject)sfOverlap), sfMigrationNew));
1714:   PetscCall(PetscSFSetGraph(*sfMigrationNew, nroots, nleaves, NULL, PETSC_OWN_POINTER, newRemote, PETSC_OWN_POINTER));
1715:   PetscFunctionReturn(PETSC_SUCCESS);
1716: }

1718: /*@
1719:   DMPlexDistribute - Distributes the mesh and any associated sections.

1721:   Collective

1723:   Input Parameters:
1724: + dm      - The original `DMPLEX` object
1725: - overlap - The overlap of partitions, 0 is the default

1727:   Output Parameters:
1728: + sf         - The `PetscSF` used for point distribution, or `NULL` if not needed
1729: - dmParallel - The distributed `DMPLEX` object

1731:   Level: intermediate

1733:   Note:
1734:   If the mesh was not distributed, the output `dmParallel` will be `NULL`.

1736:   The user can control the definition of adjacency for the mesh using `DMSetAdjacency()`. They should choose the combination appropriate for the function
1737:   representation on the mesh.

1739: .seealso: `DMPLEX`, `DM`, `DMPlexCreate()`, `DMSetAdjacency()`, `DMPlexGetOverlap()`
1740: @*/
1741: PetscErrorCode DMPlexDistribute(DM dm, PetscInt overlap, PetscSF *sf, DM *dmParallel)
1742: {
1743:   MPI_Comm         comm;
1744:   PetscPartitioner partitioner;
1745:   IS               cellPart;
1746:   PetscSection     cellPartSection;
1747:   DM               dmCoord;
1748:   DMLabel          lblPartition, lblMigration;
1749:   PetscSF          sfMigration, sfStratified, sfPoint;
1750:   PetscBool        flg, balance;
1751:   PetscMPIInt      rank, size;

1753:   PetscFunctionBegin;
1756:   if (sf) PetscAssertPointer(sf, 3);
1757:   PetscAssertPointer(dmParallel, 4);

1759:   if (sf) *sf = NULL;
1760:   *dmParallel = NULL;
1761:   PetscCall(PetscObjectGetComm((PetscObject)dm, &comm));
1762:   PetscCallMPI(MPI_Comm_rank(comm, &rank));
1763:   PetscCallMPI(MPI_Comm_size(comm, &size));
1764:   if (size == 1) PetscFunctionReturn(PETSC_SUCCESS);

1766:   PetscCall(PetscLogEventBegin(DMPLEX_Distribute, dm, 0, 0, 0));
1767:   /* Create cell partition */
1768:   PetscCall(PetscLogEventBegin(DMPLEX_Partition, dm, 0, 0, 0));
1769:   PetscCall(PetscSectionCreate(comm, &cellPartSection));
1770:   PetscCall(DMPlexGetPartitioner(dm, &partitioner));
1771:   PetscCall(PetscPartitionerDMPlexPartition(partitioner, dm, NULL, cellPartSection, &cellPart));
1772:   PetscCall(PetscLogEventBegin(DMPLEX_PartSelf, dm, 0, 0, 0));
1773:   {
1774:     /* Convert partition to DMLabel */
1775:     IS              is;
1776:     PetscHSetI      ht;
1777:     const PetscInt *points;
1778:     PetscInt       *iranks;
1779:     PetscInt        pStart, pEnd, proc, npoints, poff = 0, nranks;

1781:     PetscCall(DMLabelCreate(PETSC_COMM_SELF, "Point Partition", &lblPartition));
1782:     /* Preallocate strata */
1783:     PetscCall(PetscHSetICreate(&ht));
1784:     PetscCall(PetscSectionGetChart(cellPartSection, &pStart, &pEnd));
1785:     for (proc = pStart; proc < pEnd; proc++) {
1786:       PetscCall(PetscSectionGetDof(cellPartSection, proc, &npoints));
1787:       if (npoints) PetscCall(PetscHSetIAdd(ht, proc));
1788:     }
1789:     PetscCall(PetscHSetIGetSize(ht, &nranks));
1790:     PetscCall(PetscMalloc1(nranks, &iranks));
1791:     PetscCall(PetscHSetIGetElems(ht, &poff, iranks));
1792:     PetscCall(PetscHSetIDestroy(&ht));
1793:     PetscCall(DMLabelAddStrata(lblPartition, nranks, iranks));
1794:     PetscCall(PetscFree(iranks));
1795:     /* Inline DMPlexPartitionLabelClosure() */
1796:     PetscCall(ISGetIndices(cellPart, &points));
1797:     PetscCall(PetscSectionGetChart(cellPartSection, &pStart, &pEnd));
1798:     for (proc = pStart; proc < pEnd; proc++) {
1799:       PetscCall(PetscSectionGetDof(cellPartSection, proc, &npoints));
1800:       if (!npoints) continue;
1801:       PetscCall(PetscSectionGetOffset(cellPartSection, proc, &poff));
1802:       PetscCall(DMPlexClosurePoints_Private(dm, npoints, points + poff, &is));
1803:       PetscCall(DMLabelSetStratumIS(lblPartition, proc, is));
1804:       PetscCall(ISDestroy(&is));
1805:     }
1806:     PetscCall(ISRestoreIndices(cellPart, &points));
1807:   }
1808:   PetscCall(PetscLogEventEnd(DMPLEX_PartSelf, dm, 0, 0, 0));

1810:   PetscCall(DMLabelCreate(PETSC_COMM_SELF, "Point migration", &lblMigration));
1811:   PetscCall(DMPlexPartitionLabelInvert(dm, lblPartition, NULL, lblMigration));
1812:   PetscCall(DMPlexPartitionLabelCreateSF(dm, lblMigration, PETSC_TRUE, &sfMigration));
1813:   PetscCall(DMPlexStratifyMigrationSF(dm, sfMigration, &sfStratified));
1814:   PetscCall(PetscSFDestroy(&sfMigration));
1815:   sfMigration = sfStratified;
1816:   PetscCall(PetscSFSetUp(sfMigration));
1817:   PetscCall(PetscLogEventEnd(DMPLEX_Partition, dm, 0, 0, 0));
1818:   PetscCall(PetscOptionsHasName(((PetscObject)dm)->options, ((PetscObject)dm)->prefix, "-partition_view", &flg));
1819:   if (flg) {
1820:     PetscCall(DMLabelView(lblPartition, PETSC_VIEWER_STDOUT_(comm)));
1821:     PetscCall(PetscSFView(sfMigration, PETSC_VIEWER_STDOUT_(comm)));
1822:   }

1824:   /* Create non-overlapping parallel DM and migrate internal data */
1825:   PetscCall(DMPlexCreate(comm, dmParallel));
1826:   PetscCall(PetscObjectSetName((PetscObject)*dmParallel, "Parallel Mesh"));
1827:   PetscCall(DMPlexMigrate(dm, sfMigration, *dmParallel));

1829:   /* Build the point SF without overlap */
1830:   PetscCall(DMPlexGetPartitionBalance(dm, &balance));
1831:   PetscCall(DMPlexSetPartitionBalance(*dmParallel, balance));
1832:   PetscCall(DMPlexCreatePointSF(*dmParallel, sfMigration, PETSC_TRUE, &sfPoint));
1833:   PetscCall(DMSetPointSF(*dmParallel, sfPoint));
1834:   PetscCall(DMPlexMigrateIsoperiodicFaceSF_Internal(dm, *dmParallel, sfMigration));
1835:   PetscCall(DMGetCoordinateDM(*dmParallel, &dmCoord));
1836:   if (dmCoord) PetscCall(DMSetPointSF(dmCoord, sfPoint));
1837:   if (flg) PetscCall(PetscSFView(sfPoint, NULL));

1839:   if (overlap > 0) {
1840:     DM      dmOverlap;
1841:     PetscSF sfOverlap, sfOverlapPoint;

1843:     /* Add the partition overlap to the distributed DM */
1844:     PetscCall(DMPlexDistributeOverlap(*dmParallel, overlap, &sfOverlap, &dmOverlap));
1845:     PetscCall(DMDestroy(dmParallel));
1846:     *dmParallel = dmOverlap;
1847:     if (flg) {
1848:       PetscCall(PetscPrintf(comm, "Overlap Migration SF:\n"));
1849:       PetscCall(PetscSFView(sfOverlap, NULL));
1850:     }

1852:     /* Re-map the migration SF to establish the full migration pattern */
1853:     PetscCall(DMPlexRemapMigrationSF(sfOverlap, sfMigration, &sfOverlapPoint));
1854:     PetscCall(PetscSFDestroy(&sfOverlap));
1855:     PetscCall(PetscSFDestroy(&sfMigration));
1856:     sfMigration = sfOverlapPoint;
1857:   }
1858:   /* Cleanup Partition */
1859:   PetscCall(DMLabelDestroy(&lblPartition));
1860:   PetscCall(DMLabelDestroy(&lblMigration));
1861:   PetscCall(PetscSectionDestroy(&cellPartSection));
1862:   PetscCall(ISDestroy(&cellPart));
1863:   PetscCall(DMPlexCopy_Internal(dm, PETSC_TRUE, PETSC_FALSE, *dmParallel));
1864:   // Create sfNatural, need discretization information
1865:   PetscCall(DMCopyDisc(dm, *dmParallel));
1866:   if (dm->localSection) {
1867:     PetscSection psection;
1868:     PetscCall(PetscSectionCreate(PetscObjectComm((PetscObject)dm), &psection));
1869:     PetscCall(PetscSFDistributeSection(sfMigration, dm->localSection, NULL, psection));
1870:     PetscCall(DMSetLocalSection(*dmParallel, psection));
1871:     PetscCall(PetscSectionDestroy(&psection));
1872:   }
1873:   if (dm->useNatural) {
1874:     PetscSection section;

1876:     PetscCall(DMSetUseNatural(*dmParallel, PETSC_TRUE));
1877:     PetscCall(DMGetLocalSection(dm, &section));

1879:     /* If DM has useNatural = PETSC_TRUE, but no sfNatural is set, the DM's Section is considered natural */
1880:     /* sfMigration and sfNatural are respectively the point and dofs SFs mapping to this natural DM */
1881:     /* Compose with a previous sfNatural if present */
1882:     if (dm->sfNatural) {
1883:       PetscCall(DMPlexMigrateGlobalToNaturalSF(dm, *dmParallel, dm->sfNatural, sfMigration, &(*dmParallel)->sfNatural));
1884:     } else {
1885:       PetscCall(DMPlexCreateGlobalToNaturalSF(*dmParallel, section, sfMigration, &(*dmParallel)->sfNatural));
1886:     }
1887:     /* Compose with a previous sfMigration if present */
1888:     if (dm->sfMigration) {
1889:       PetscSF naturalPointSF;

1891:       PetscCall(PetscSFCompose(dm->sfMigration, sfMigration, &naturalPointSF));
1892:       PetscCall(PetscSFDestroy(&sfMigration));
1893:       sfMigration = naturalPointSF;
1894:     }
1895:   }
1896:   /* Cleanup */
1897:   if (sf) {
1898:     *sf = sfMigration;
1899:   } else PetscCall(PetscSFDestroy(&sfMigration));
1900:   PetscCall(PetscSFDestroy(&sfPoint));
1901:   PetscCall(PetscLogEventEnd(DMPLEX_Distribute, dm, 0, 0, 0));
1902:   PetscFunctionReturn(PETSC_SUCCESS);
1903: }

1905: PetscErrorCode DMPlexDistributeOverlap_Internal(DM dm, PetscInt overlap, MPI_Comm newcomm, const char *ovlboundary, PetscSF *sf, DM *dmOverlap)
1906: {
1907:   DM_Plex     *mesh = (DM_Plex *)dm->data;
1908:   MPI_Comm     comm;
1909:   PetscMPIInt  size, rank;
1910:   PetscSection rootSection, leafSection;
1911:   IS           rootrank, leafrank;
1912:   DM           dmCoord;
1913:   DMLabel      lblOverlap;
1914:   PetscSF      sfOverlap, sfStratified, sfPoint;
1915:   PetscBool    clear_ovlboundary;

1917:   PetscFunctionBegin;
1918:   if (sf) *sf = NULL;
1919:   *dmOverlap = NULL;
1920:   PetscCall(PetscObjectGetComm((PetscObject)dm, &comm));
1921:   PetscCallMPI(MPI_Comm_size(comm, &size));
1922:   PetscCallMPI(MPI_Comm_rank(comm, &rank));
1923:   if (size == 1) PetscFunctionReturn(PETSC_SUCCESS);
1924:   {
1925:     // We need to get options for the _already_distributed mesh, so it must be done here
1926:     PetscInt    overlap;
1927:     const char *prefix;
1928:     char        oldPrefix[PETSC_MAX_PATH_LEN];

1930:     oldPrefix[0] = '\0';
1931:     PetscCall(PetscObjectGetOptionsPrefix((PetscObject)dm, &prefix));
1932:     PetscCall(PetscStrncpy(oldPrefix, prefix, sizeof(oldPrefix)));
1933:     PetscCall(PetscObjectAppendOptionsPrefix((PetscObject)dm, "dist_"));
1934:     PetscCall(DMPlexGetOverlap(dm, &overlap));
1935:     PetscObjectOptionsBegin((PetscObject)dm);
1936:     PetscCall(DMSetFromOptions_Overlap_Plex(dm, PetscOptionsObject, &overlap));
1937:     PetscOptionsEnd();
1938:     PetscCall(PetscObjectSetOptionsPrefix((PetscObject)dm, oldPrefix[0] == '\0' ? NULL : oldPrefix));
1939:   }
1940:   if (ovlboundary) {
1941:     PetscBool flg;
1942:     PetscCall(DMHasLabel(dm, ovlboundary, &flg));
1943:     if (!flg) {
1944:       DMLabel label;

1946:       PetscCall(DMCreateLabel(dm, ovlboundary));
1947:       PetscCall(DMGetLabel(dm, ovlboundary, &label));
1948:       PetscCall(DMPlexMarkBoundaryFaces(dm, 1, label));
1949:       clear_ovlboundary = PETSC_TRUE;
1950:     }
1951:   }
1952:   PetscCall(PetscLogEventBegin(DMPLEX_DistributeOverlap, dm, 0, 0, 0));
1953:   /* Compute point overlap with neighbouring processes on the distributed DM */
1954:   PetscCall(PetscLogEventBegin(DMPLEX_Partition, dm, 0, 0, 0));
1955:   PetscCall(PetscSectionCreate(newcomm, &rootSection));
1956:   PetscCall(PetscSectionCreate(newcomm, &leafSection));
1957:   PetscCall(DMPlexDistributeOwnership(dm, rootSection, &rootrank, leafSection, &leafrank));
1958:   if (mesh->numOvLabels) PetscCall(DMPlexCreateOverlapLabelFromLabels(dm, mesh->numOvLabels, mesh->ovLabels, mesh->ovValues, mesh->numOvExLabels, mesh->ovExLabels, mesh->ovExValues, rootSection, rootrank, leafSection, leafrank, &lblOverlap));
1959:   else PetscCall(DMPlexCreateOverlapLabel(dm, overlap, rootSection, rootrank, leafSection, leafrank, &lblOverlap));
1960:   /* Convert overlap label to stratified migration SF */
1961:   PetscCall(DMPlexPartitionLabelCreateSF(dm, lblOverlap, PETSC_FALSE, &sfOverlap));
1962:   PetscCall(DMPlexStratifyMigrationSF(dm, sfOverlap, &sfStratified));
1963:   PetscCall(PetscSFDestroy(&sfOverlap));
1964:   sfOverlap = sfStratified;
1965:   PetscCall(PetscObjectSetName((PetscObject)sfOverlap, "Overlap SF"));
1966:   PetscCall(PetscSFSetFromOptions(sfOverlap));

1968:   PetscCall(PetscSectionDestroy(&rootSection));
1969:   PetscCall(PetscSectionDestroy(&leafSection));
1970:   PetscCall(ISDestroy(&rootrank));
1971:   PetscCall(ISDestroy(&leafrank));
1972:   PetscCall(PetscLogEventEnd(DMPLEX_Partition, dm, 0, 0, 0));

1974:   /* Build the overlapping DM */
1975:   PetscCall(DMPlexCreate(newcomm, dmOverlap));
1976:   PetscCall(PetscObjectSetName((PetscObject)*dmOverlap, "Parallel Mesh"));
1977:   PetscCall(DMPlexMigrate(dm, sfOverlap, *dmOverlap));
1978:   /* Store the overlap in the new DM */
1979:   PetscCall(DMPlexSetOverlap_Plex(*dmOverlap, dm, overlap));
1980:   /* Build the new point SF */
1981:   PetscCall(DMPlexCreatePointSF(*dmOverlap, sfOverlap, PETSC_FALSE, &sfPoint));
1982:   PetscCall(DMSetPointSF(*dmOverlap, sfPoint));
1983:   PetscCall(DMGetCoordinateDM(*dmOverlap, &dmCoord));
1984:   if (dmCoord) PetscCall(DMSetPointSF(dmCoord, sfPoint));
1985:   PetscCall(DMGetCellCoordinateDM(*dmOverlap, &dmCoord));
1986:   if (dmCoord) PetscCall(DMSetPointSF(dmCoord, sfPoint));
1987:   PetscCall(PetscSFDestroy(&sfPoint));
1988:   PetscCall(DMPlexCopy_Internal(dm, PETSC_TRUE, PETSC_FALSE, *dmOverlap));
1989:   /* TODO: labels stored inside the DS for regions should be handled here */
1990:   PetscCall(DMCopyDisc(dm, *dmOverlap));
1991:   /* Cleanup overlap partition */
1992:   PetscCall(DMLabelDestroy(&lblOverlap));
1993:   if (sf) *sf = sfOverlap;
1994:   else PetscCall(PetscSFDestroy(&sfOverlap));
1995:   if (ovlboundary) {
1996:     DMLabel   label;
1997:     PetscBool flg;

1999:     if (clear_ovlboundary) PetscCall(DMRemoveLabel(dm, ovlboundary, NULL));
2000:     PetscCall(DMHasLabel(*dmOverlap, ovlboundary, &flg));
2001:     PetscCheck(flg, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Missing %s label", ovlboundary);
2002:     PetscCall(DMGetLabel(*dmOverlap, ovlboundary, &label));
2003:     PetscCall(DMPlexMarkBoundaryFaces_Internal(*dmOverlap, 1, 0, label, PETSC_TRUE));
2004:   }
2005:   PetscCall(PetscLogEventEnd(DMPLEX_DistributeOverlap, dm, 0, 0, 0));
2006:   PetscFunctionReturn(PETSC_SUCCESS);
2007: }

2009: /*@
2010:   DMPlexDistributeOverlap - Add partition overlap to a distributed non-overlapping `DM`.

2012:   Collective

2014:   Input Parameters:
2015: + dm      - The non-overlapping distributed `DMPLEX` object
2016: - overlap - The overlap of partitions (the same on all ranks)

2018:   Output Parameters:
2019: + sf        - The `PetscSF` used for point distribution, or pass `NULL` if not needed
2020: - dmOverlap - The overlapping distributed `DMPLEX` object

2022:   Options Database Keys:
2023: + -dm_plex_overlap_labels <name1,name2,...> - List of overlap label names
2024: . -dm_plex_overlap_values <int1,int2,...>   - List of overlap label values
2025: . -dm_plex_overlap_exclude_label <name>     - Label used to exclude points from overlap
2026: - -dm_plex_overlap_exclude_value <int>      - Label value used to exclude points from overlap

2028:   Level: advanced

2030:   Notes:
2031:   If the mesh was not distributed, the return value is `NULL`.

2033:   The user can control the definition of adjacency for the mesh using `DMSetAdjacency()`. They should choose the combination appropriate for the function
2034:   representation on the mesh.

2036: .seealso: `DMPLEX`, `PetscSF`, `DM`, `DMPlexCreate()`, `DMSetAdjacency()`, `DMPlexDistribute()`, `DMPlexCreateOverlapLabel()`, `DMPlexGetOverlap()`
2037: @*/
2038: PetscErrorCode DMPlexDistributeOverlap(DM dm, PetscInt overlap, PetscSF *sf, DM *dmOverlap)
2039: {
2040:   PetscFunctionBegin;
2043:   if (sf) PetscAssertPointer(sf, 3);
2044:   PetscAssertPointer(dmOverlap, 4);
2045:   PetscCall(DMPlexDistributeOverlap_Internal(dm, overlap, PetscObjectComm((PetscObject)dm), NULL, sf, dmOverlap));
2046:   PetscFunctionReturn(PETSC_SUCCESS);
2047: }

2049: PetscErrorCode DMPlexGetOverlap_Plex(DM dm, PetscInt *overlap)
2050: {
2051:   DM_Plex *mesh = (DM_Plex *)dm->data;

2053:   PetscFunctionBegin;
2054:   *overlap = mesh->overlap;
2055:   PetscFunctionReturn(PETSC_SUCCESS);
2056: }

2058: PetscErrorCode DMPlexSetOverlap_Plex(DM dm, DM dmSrc, PetscInt overlap)
2059: {
2060:   DM_Plex *mesh    = NULL;
2061:   DM_Plex *meshSrc = NULL;

2063:   PetscFunctionBegin;
2065:   mesh = (DM_Plex *)dm->data;
2066:   if (dmSrc) {
2068:     meshSrc       = (DM_Plex *)dmSrc->data;
2069:     mesh->overlap = meshSrc->overlap;
2070:   } else {
2071:     mesh->overlap = 0;
2072:   }
2073:   mesh->overlap += overlap;
2074:   PetscFunctionReturn(PETSC_SUCCESS);
2075: }

2077: /*@
2078:   DMPlexGetOverlap - Get the width of the cell overlap

2080:   Not Collective

2082:   Input Parameter:
2083: . dm - The `DM`

2085:   Output Parameter:
2086: . overlap - the width of the cell overlap

2088:   Level: intermediate

2090: .seealso: `DMPLEX`, `DMPlexSetOverlap()`, `DMPlexDistribute()`
2091: @*/
2092: PetscErrorCode DMPlexGetOverlap(DM dm, PetscInt *overlap)
2093: {
2094:   PetscFunctionBegin;
2096:   PetscAssertPointer(overlap, 2);
2097:   PetscUseMethod(dm, "DMPlexGetOverlap_C", (DM, PetscInt *), (dm, overlap));
2098:   PetscFunctionReturn(PETSC_SUCCESS);
2099: }

2101: /*@
2102:   DMPlexSetOverlap - Set the width of the cell overlap

2104:   Logically Collective

2106:   Input Parameters:
2107: + dm      - The `DM`
2108: . dmSrc   - The `DM` that produced this one, or `NULL`
2109: - overlap - the width of the cell overlap

2111:   Level: intermediate

2113:   Note:
2114:   The overlap from `dmSrc` is added to `dm`

2116: .seealso: `DMPLEX`, `DMPlexGetOverlap()`, `DMPlexDistribute()`
2117: @*/
2118: PetscErrorCode DMPlexSetOverlap(DM dm, DM dmSrc, PetscInt overlap)
2119: {
2120:   PetscFunctionBegin;
2123:   PetscTryMethod(dm, "DMPlexSetOverlap_C", (DM, DM, PetscInt), (dm, dmSrc, overlap));
2124:   PetscFunctionReturn(PETSC_SUCCESS);
2125: }

2127: PetscErrorCode DMPlexDistributeSetDefault_Plex(DM dm, PetscBool dist)
2128: {
2129:   DM_Plex *mesh = (DM_Plex *)dm->data;

2131:   PetscFunctionBegin;
2132:   mesh->distDefault = dist;
2133:   PetscFunctionReturn(PETSC_SUCCESS);
2134: }

2136: /*@
2137:   DMPlexDistributeSetDefault - Set flag indicating whether the `DM` should be distributed by default

2139:   Logically Collective

2141:   Input Parameters:
2142: + dm   - The `DM`
2143: - dist - Flag for distribution

2145:   Level: intermediate

2147: .seealso: `DMPLEX`, `DMPlexDistributeGetDefault()`, `DMPlexDistribute()`
2148: @*/
2149: PetscErrorCode DMPlexDistributeSetDefault(DM dm, PetscBool dist)
2150: {
2151:   PetscFunctionBegin;
2154:   PetscTryMethod(dm, "DMPlexDistributeSetDefault_C", (DM, PetscBool), (dm, dist));
2155:   PetscFunctionReturn(PETSC_SUCCESS);
2156: }

2158: PetscErrorCode DMPlexDistributeGetDefault_Plex(DM dm, PetscBool *dist)
2159: {
2160:   DM_Plex *mesh = (DM_Plex *)dm->data;

2162:   PetscFunctionBegin;
2163:   *dist = mesh->distDefault;
2164:   PetscFunctionReturn(PETSC_SUCCESS);
2165: }

2167: /*@
2168:   DMPlexDistributeGetDefault - Get flag indicating whether the `DM` should be distributed by default

2170:   Not Collective

2172:   Input Parameter:
2173: . dm - The `DM`

2175:   Output Parameter:
2176: . dist - Flag for distribution

2178:   Level: intermediate

2180: .seealso: `DMPLEX`, `DM`, `DMPlexDistributeSetDefault()`, `DMPlexDistribute()`
2181: @*/
2182: PetscErrorCode DMPlexDistributeGetDefault(DM dm, PetscBool *dist)
2183: {
2184:   PetscFunctionBegin;
2186:   PetscAssertPointer(dist, 2);
2187:   PetscUseMethod(dm, "DMPlexDistributeGetDefault_C", (DM, PetscBool *), (dm, dist));
2188:   PetscFunctionReturn(PETSC_SUCCESS);
2189: }

2191: /*@C
2192:   DMPlexGetGatherDM - Get a copy of the `DMPLEX` that gathers all points on the
2193:   root process of the original's communicator.

2195:   Collective

2197:   Input Parameter:
2198: . dm - the original `DMPLEX` object

2200:   Output Parameters:
2201: + sf         - the `PetscSF` used for point distribution (optional)
2202: - gatherMesh - the gathered `DM` object, or `NULL`

2204:   Level: intermediate

2206: .seealso: `DMPLEX`, `DM`, `PetscSF`, `DMPlexDistribute()`, `DMPlexGetRedundantDM()`
2207: @*/
2208: PetscErrorCode DMPlexGetGatherDM(DM dm, PetscSF *sf, DM *gatherMesh)
2209: {
2210:   MPI_Comm         comm;
2211:   PetscMPIInt      size;
2212:   PetscPartitioner oldPart, gatherPart;

2214:   PetscFunctionBegin;
2216:   PetscAssertPointer(gatherMesh, 3);
2217:   *gatherMesh = NULL;
2218:   if (sf) *sf = NULL;
2219:   comm = PetscObjectComm((PetscObject)dm);
2220:   PetscCallMPI(MPI_Comm_size(comm, &size));
2221:   if (size == 1) PetscFunctionReturn(PETSC_SUCCESS);
2222:   PetscCall(DMPlexGetPartitioner(dm, &oldPart));
2223:   PetscCall(PetscObjectReference((PetscObject)oldPart));
2224:   PetscCall(PetscPartitionerCreate(comm, &gatherPart));
2225:   PetscCall(PetscPartitionerSetType(gatherPart, PETSCPARTITIONERGATHER));
2226:   PetscCall(DMPlexSetPartitioner(dm, gatherPart));
2227:   PetscCall(DMPlexDistribute(dm, 0, sf, gatherMesh));

2229:   PetscCall(DMPlexSetPartitioner(dm, oldPart));
2230:   PetscCall(PetscPartitionerDestroy(&gatherPart));
2231:   PetscCall(PetscPartitionerDestroy(&oldPart));
2232:   PetscFunctionReturn(PETSC_SUCCESS);
2233: }

2235: /*@C
2236:   DMPlexGetRedundantDM - Get a copy of the `DMPLEX` that is completely copied on each process.

2238:   Collective

2240:   Input Parameter:
2241: . dm - the original `DMPLEX` object

2243:   Output Parameters:
2244: + sf            - the `PetscSF` used for point distribution (optional)
2245: - redundantMesh - the redundant `DM` object, or `NULL`

2247:   Level: intermediate

2249: .seealso: `DMPLEX`, `DMPlexDistribute()`, `DMPlexGetGatherDM()`
2250: @*/
2251: PetscErrorCode DMPlexGetRedundantDM(DM dm, PetscSF *sf, DM *redundantMesh)
2252: {
2253:   MPI_Comm     comm;
2254:   PetscMPIInt  size, rank;
2255:   PetscInt     pStart, pEnd, p;
2256:   PetscInt     numPoints = -1;
2257:   PetscSF      migrationSF, sfPoint, gatherSF;
2258:   DM           gatherDM, dmCoord;
2259:   PetscSFNode *points;

2261:   PetscFunctionBegin;
2263:   PetscAssertPointer(redundantMesh, 3);
2264:   *redundantMesh = NULL;
2265:   comm           = PetscObjectComm((PetscObject)dm);
2266:   PetscCallMPI(MPI_Comm_size(comm, &size));
2267:   if (size == 1) {
2268:     PetscCall(PetscObjectReference((PetscObject)dm));
2269:     *redundantMesh = dm;
2270:     if (sf) *sf = NULL;
2271:     PetscFunctionReturn(PETSC_SUCCESS);
2272:   }
2273:   PetscCall(DMPlexGetGatherDM(dm, &gatherSF, &gatherDM));
2274:   if (!gatherDM) PetscFunctionReturn(PETSC_SUCCESS);
2275:   PetscCallMPI(MPI_Comm_rank(comm, &rank));
2276:   PetscCall(DMPlexGetChart(gatherDM, &pStart, &pEnd));
2277:   numPoints = pEnd - pStart;
2278:   PetscCallMPI(MPI_Bcast(&numPoints, 1, MPIU_INT, 0, comm));
2279:   PetscCall(PetscMalloc1(numPoints, &points));
2280:   PetscCall(PetscSFCreate(comm, &migrationSF));
2281:   for (p = 0; p < numPoints; p++) {
2282:     points[p].index = p;
2283:     points[p].rank  = 0;
2284:   }
2285:   PetscCall(PetscSFSetGraph(migrationSF, pEnd - pStart, numPoints, NULL, PETSC_OWN_POINTER, points, PETSC_OWN_POINTER));
2286:   PetscCall(DMPlexCreate(comm, redundantMesh));
2287:   PetscCall(PetscObjectSetName((PetscObject)*redundantMesh, "Redundant Mesh"));
2288:   PetscCall(DMPlexMigrate(gatherDM, migrationSF, *redundantMesh));
2289:   /* This is to express that all point are in overlap */
2290:   PetscCall(DMPlexSetOverlap_Plex(*redundantMesh, NULL, PETSC_INT_MAX));
2291:   PetscCall(DMPlexCreatePointSF(*redundantMesh, migrationSF, PETSC_FALSE, &sfPoint));
2292:   PetscCall(DMSetPointSF(*redundantMesh, sfPoint));
2293:   PetscCall(DMGetCoordinateDM(*redundantMesh, &dmCoord));
2294:   if (dmCoord) PetscCall(DMSetPointSF(dmCoord, sfPoint));
2295:   PetscCall(PetscSFDestroy(&sfPoint));
2296:   if (sf) {
2297:     PetscSF tsf;

2299:     PetscCall(PetscSFCompose(gatherSF, migrationSF, &tsf));
2300:     PetscCall(DMPlexStratifyMigrationSF(dm, tsf, sf));
2301:     PetscCall(PetscSFDestroy(&tsf));
2302:   }
2303:   PetscCall(PetscSFDestroy(&migrationSF));
2304:   PetscCall(PetscSFDestroy(&gatherSF));
2305:   PetscCall(DMDestroy(&gatherDM));
2306:   PetscCall(DMCopyDisc(dm, *redundantMesh));
2307:   PetscCall(DMPlexCopy_Internal(dm, PETSC_TRUE, PETSC_FALSE, *redundantMesh));
2308:   PetscFunctionReturn(PETSC_SUCCESS);
2309: }

2311: /*@
2312:   DMPlexIsDistributed - Find out whether this `DM` is distributed, i.e. more than one rank owns some points.

2314:   Collective

2316:   Input Parameter:
2317: . dm - The `DM` object

2319:   Output Parameter:
2320: . distributed - Flag whether the `DM` is distributed

2322:   Level: intermediate

2324:   Notes:
2325:   This currently finds out whether at least two ranks have any DAG points.
2326:   This involves `MPI_Allreduce()` with one integer.
2327:   The result is currently not stashed so every call to this routine involves this global communication.

2329: .seealso: `DMPLEX`, `DMPlexDistribute()`, `DMPlexGetOverlap()`, `DMPlexIsInterpolated()`
2330: @*/
2331: PetscErrorCode DMPlexIsDistributed(DM dm, PetscBool *distributed)
2332: {
2333:   PetscInt    pStart, pEnd, count;
2334:   MPI_Comm    comm;
2335:   PetscMPIInt size;

2337:   PetscFunctionBegin;
2339:   PetscAssertPointer(distributed, 2);
2340:   PetscCall(PetscObjectGetComm((PetscObject)dm, &comm));
2341:   PetscCallMPI(MPI_Comm_size(comm, &size));
2342:   if (size == 1) {
2343:     *distributed = PETSC_FALSE;
2344:     PetscFunctionReturn(PETSC_SUCCESS);
2345:   }
2346:   PetscCall(DMPlexGetChart(dm, &pStart, &pEnd));
2347:   count = (pEnd - pStart) > 0 ? 1 : 0;
2348:   PetscCallMPI(MPIU_Allreduce(MPI_IN_PLACE, &count, 1, MPIU_INT, MPI_SUM, comm));
2349:   *distributed = count > 1 ? PETSC_TRUE : PETSC_FALSE;
2350:   PetscFunctionReturn(PETSC_SUCCESS);
2351: }

2353: /*@
2354:   DMPlexDistributionSetName - Set the name of the specific parallel distribution

2356:   Input Parameters:
2357: + dm   - The `DM`
2358: - name - The name of the specific parallel distribution

2360:   Level: developer

2362:   Note:
2363:   If distribution name is set when saving, `DMPlexTopologyView()` saves the plex's
2364:   parallel distribution (i.e., partition, ownership, and local ordering of points) under
2365:   this name. Conversely, if distribution name is set when loading, `DMPlexTopologyLoad()`
2366:   loads the parallel distribution stored in file under this name.

2368: .seealso: `DMPLEX`, `DMPlexDistributionGetName()`, `DMPlexTopologyView()`, `DMPlexTopologyLoad()`
2369: @*/
2370: PetscErrorCode DMPlexDistributionSetName(DM dm, const char name[])
2371: {
2372:   DM_Plex *mesh = (DM_Plex *)dm->data;

2374:   PetscFunctionBegin;
2376:   if (name) PetscAssertPointer(name, 2);
2377:   PetscCall(PetscFree(mesh->distributionName));
2378:   PetscCall(PetscStrallocpy(name, &mesh->distributionName));
2379:   PetscFunctionReturn(PETSC_SUCCESS);
2380: }

2382: /*@
2383:   DMPlexDistributionGetName - Retrieve the name of the specific parallel distribution

2385:   Input Parameter:
2386: . dm - The `DM`

2388:   Output Parameter:
2389: . name - The name of the specific parallel distribution

2391:   Level: developer

2393:   Note:
2394:   If distribution name is set when saving, `DMPlexTopologyView()` saves the plex's
2395:   parallel distribution (i.e., partition, ownership, and local ordering of points) under
2396:   this name. Conversely, if distribution name is set when loading, `DMPlexTopologyLoad()`
2397:   loads the parallel distribution stored in file under this name.

2399: .seealso: `DMPLEX`, `DMPlexDistributionSetName()`, `DMPlexTopologyView()`, `DMPlexTopologyLoad()`
2400: @*/
2401: PetscErrorCode DMPlexDistributionGetName(DM dm, const char *name[])
2402: {
2403:   DM_Plex *mesh = (DM_Plex *)dm->data;

2405:   PetscFunctionBegin;
2407:   PetscAssertPointer(name, 2);
2408:   *name = mesh->distributionName;
2409:   PetscFunctionReturn(PETSC_SUCCESS);
2410: }