Actual source code: plexorient.c

petsc-master 2020-10-26
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  1: #include <petsc/private/dmpleximpl.h>
  2: #include <petscsf.h>

  4: /*@
  5:   DMPlexCompareOrientations - Compare the cone of the given DAG point (cell) with the given reference cone (with the same cone points modulo order), and return relative orientation.

  7:   Not Collective

  9:   Input Parameters:
 10: + dm              - The DM (DMPLEX)
 11: . p               - The DAG point whose cone is compared
 12: . masterConeSize  - Number of the reference cone points passed (at least 2 and at most size of the cone of p)
 13: - masterCone      - The reference cone points

 15:   Output Parameters:
 16: + start           - The new starting point within the cone of p to make it conforming with the reference cone
 17: - reverse         - The flag whether the order of the cone points should be reversed

 19:   Level: advanced

 21: .seealso: DMPlexOrient(), DMPlexOrientCell()
 22: @*/
 23: PetscErrorCode DMPlexCompareOrientations(DM dm, PetscInt p, PetscInt masterConeSize, const PetscInt masterCone[], PetscInt *start, PetscBool *reverse)
 24: {
 25:   PetscInt        coneSize;
 26:   const PetscInt *cone;
 27:   PetscInt        i, start_;
 28:   PetscBool       reverse_;
 29:   PetscErrorCode  ierr;

 33:   DMPlexGetConeSize(dm, p, &coneSize);
 34:   if (coneSize < 2) SETERRQ1(PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Point %D has no cone", p);
 35:   DMPlexGetCone(dm, p, &cone);
 36:   if (masterConeSize < 2) SETERRQ1(PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Point %D: masterConeSize must be at least 2", p);
 37:   if (masterConeSize > coneSize) SETERRQ1(PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Point %D: masterConeSize must be at most coneSize", p);
 38:   start_ = 0;
 39:   for (i=0; i<coneSize; i++) {
 40:     if (cone[i] == masterCone[0]) {
 41:       start_ = i;
 42:       break;
 43:     }
 44:   }
 45:   if (PetscUnlikely(i==coneSize)) SETERRQ1(PETSC_COMM_SELF, PETSC_ERR_ARG_INCOMP, "Point %D: starting point of reference cone not found in slave cone", p);
 46:   reverse_ = PETSC_FALSE;
 47:   for (i=0; i<masterConeSize; i++) {if (cone[(start_+i)%coneSize] != masterCone[i]) break;}
 48:   if (i != masterConeSize) {
 49:     reverse_ = PETSC_TRUE;
 50:     for (i=0; i<masterConeSize; i++) {if (cone[(coneSize+start_-i)%coneSize] != masterCone[i]) break;}
 51:     if (i < masterConeSize) SETERRQ1(PETSC_COMM_SELF, PETSC_ERR_ARG_INCOMP, "Point %D: cone has non-conforming order of points with respect to reference cone", p);
 52:   }
 53:   if (start) *start = start_;
 54:   if (reverse) *reverse = reverse_;
 55:   if (PetscUnlikely(cone[start_] != masterCone[0])) SETERRQ4(PETSC_COMM_SELF, PETSC_ERR_PLIB, "Point %D: cone[%d] = %d != %d = masterCone[0]", p, start_, cone[start_], masterCone[0]);
 56:   return(0);
 57: }

 59: /*@
 60:   DMPlexOrientCell - Set the desired order of cone points of this DAG point, and fix orientations accordingly.

 62:   Not Collective

 64:   Input Parameters:
 65: + dm              - The DM
 66: . p               - The DAG point (from interval given by DMPlexGetChart())
 67: . masterConeSize  - Number of specified cone points (at least 2)
 68: - masterCone      - Specified cone points, i.e. ordered subset of current cone in DAG numbering (not cone-local numbering)

 70:   Level: intermediate

 72: .seealso: DMPlexOrient(), DMPlexGetCone(), DMPlexGetConeOrientation(), DMPlexInterpolate(), DMPlexGetChart()
 73: @*/
 74: PetscErrorCode DMPlexOrientCell(DM dm, PetscInt p, PetscInt masterConeSize, const PetscInt masterCone[])
 75: {
 76:   PetscInt        coneSize;
 77:   PetscInt        start1=0;
 78:   PetscBool       reverse1=PETSC_FALSE;
 79:   PetscErrorCode  ierr;

 84:   if (masterConeSize == 1) SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "masterConeSize cannot be 1");
 85:   DMPlexGetConeSize(dm, p, &coneSize);
 86:   if (!coneSize) return(0); /* do nothing for points with no cone */
 87:   DMPlexCompareOrientations(dm, p, masterConeSize, masterCone, &start1, &reverse1);
 88:   DMPlexOrientCell_Internal(dm, p, start1, reverse1);
 89:   if (PetscDefined(USE_DEBUG)) {
 90:     PetscInt        c;
 91:     const PetscInt *cone;
 92:     DMPlexGetCone(dm, p, &cone);
 93:     for (c = 0; c < masterConeSize; c++) {
 94:       if (PetscUnlikely(cone[c] != masterCone[c])) SETERRQ4(PETSC_COMM_SELF, PETSC_ERR_PLIB, "The algorithm above is wrong as cone[%d] = %d != %d = masterCone[%d]", c, cone[c], masterCone[c], c);
 95:     }
 96:   }
 97:   return(0);
 98: }

100: PetscErrorCode DMPlexOrientCell_Internal(DM dm, PetscInt p, PetscInt start1, PetscBool reverse1)
101: {
102:   PetscInt        i, j, k, maxConeSize, coneSize, coneConeSize, supportSize, supportConeSize;
103:   PetscInt        start0, start;
104:   PetscBool       reverse0, reverse;
105:   PetscInt        newornt;
106:   const PetscInt *cone=NULL, *support=NULL, *supportCone=NULL, *ornts=NULL;
107:   PetscInt       *newcone=NULL, *newornts=NULL;
108:   PetscErrorCode  ierr;

111:   if (!start1 && !reverse1) return(0);
112:   DMPlexGetConeSize(dm, p, &coneSize);
113:   if (!coneSize) return(0); /* do nothing for points with no cone */
114:   DMPlexGetCone(dm, p, &cone);
115:   DMPlexGetMaxSizes(dm, &maxConeSize, NULL);
116:   /* permute p's cone and orientations */
117:   DMPlexGetConeOrientation(dm, p, &ornts);
118:   DMGetWorkArray(dm, maxConeSize, MPIU_INT, &newcone);
119:   DMGetWorkArray(dm, maxConeSize, MPIU_INT, &newornts);
120:   DMPlexFixFaceOrientations_Permute_Private(coneSize, cone, start1, reverse1, newcone);
121:   DMPlexFixFaceOrientations_Permute_Private(coneSize, ornts, start1, reverse1, newornts);
122:   /* if direction of p (face) is flipped, flip also p's cone points (edges) */
123:   if (reverse1) {
124:     for (i=0; i<coneSize; i++) {
125:       DMPlexGetConeSize(dm, cone[i], &coneConeSize);
126:       DMPlexFixFaceOrientations_Translate_Private(newornts[i], &start0, &reverse0);
127:       DMPlexFixFaceOrientations_Combine_Private(coneConeSize, start0, reverse0, 1, PETSC_FALSE, &start, &reverse);
128:       DMPlexFixFaceOrientations_TranslateBack_Private(coneConeSize, start, reverse, &newornts[i]);
129:     }
130:   }
131:   DMPlexSetConeOrientation(dm, p, newornts);
132:   /* fix oriention of p within cones of p's support points */
133:   DMPlexGetSupport(dm, p, &support);
134:   DMPlexGetSupportSize(dm, p, &supportSize);
135:   for (j=0; j<supportSize; j++) {
136:     DMPlexGetCone(dm, support[j], &supportCone);
137:     DMPlexGetConeSize(dm, support[j], &supportConeSize);
138:     DMPlexGetConeOrientation(dm, support[j], &ornts);
139:     for (k=0; k<supportConeSize; k++) {
140:       if (supportCone[k] != p) continue;
141:       DMPlexFixFaceOrientations_Translate_Private(ornts[k], &start0, &reverse0);
142:       DMPlexFixFaceOrientations_Combine_Private(coneSize, start0, reverse0, start1, reverse1, &start, &reverse);
143:       DMPlexFixFaceOrientations_TranslateBack_Private(coneSize, start, reverse, &newornt);
144:       DMPlexInsertConeOrientation(dm, support[j], k, newornt);
145:     }
146:   }
147:   /* rewrite cone */
148:   DMPlexSetCone(dm, p, newcone);
149:   DMRestoreWorkArray(dm, maxConeSize, MPIU_INT, &newcone);
150:   DMRestoreWorkArray(dm, maxConeSize, MPIU_INT, &newornts);
151:   return(0);
152: }

154: /*@
155:   DMPlexReverseCell - Give a mesh cell the opposite orientation

157:   Input Parameters:
158: + dm   - The DM
159: - cell - The cell number

161:   Note: The modification of the DM is done in-place.

163:   Level: advanced

165: .seealso: DMPlexOrient(), DMCreate(), DMPLEX
166: @*/
167: PetscErrorCode DMPlexReverseCell(DM dm, PetscInt cell)
168: {
169:   /* Note that the reverse orientation ro of a face with orientation o is:

171:        ro = o >= 0 ? -(faceSize - o) : faceSize + o

173:      where faceSize is the size of the cone for the face.
174:   */
175:   const PetscInt *cone,    *coneO, *support;
176:   PetscInt       *revcone, *revconeO;
177:   PetscInt        maxConeSize, coneSize, supportSize, faceSize, cp, sp;
178:   PetscErrorCode  ierr;

181:   DMPlexGetMaxSizes(dm, &maxConeSize, NULL);
182:   DMGetWorkArray(dm, maxConeSize, MPIU_INT, &revcone);
183:   DMGetWorkArray(dm, maxConeSize, MPIU_INT, &revconeO);
184:   /* Reverse cone, and reverse orientations of faces */
185:   DMPlexGetConeSize(dm, cell, &coneSize);
186:   DMPlexGetCone(dm, cell, &cone);
187:   DMPlexGetConeOrientation(dm, cell, &coneO);
188:   for (cp = 0; cp < coneSize; ++cp) {
189:     const PetscInt rcp = coneSize-cp-1;

191:     DMPlexGetConeSize(dm, cone[rcp], &faceSize);
192:     revcone[cp]  = cone[rcp];
193:     revconeO[cp] = coneO[rcp] >= 0 ? -(faceSize-coneO[rcp]) : faceSize+coneO[rcp];
194:   }
195:   DMPlexSetCone(dm, cell, revcone);
196:   DMPlexSetConeOrientation(dm, cell, revconeO);
197:   /* Reverse orientation of this cell in the support hypercells */
198:   faceSize = coneSize;
199:   DMPlexGetSupportSize(dm, cell, &supportSize);
200:   DMPlexGetSupport(dm, cell, &support);
201:   for (sp = 0; sp < supportSize; ++sp) {
202:     DMPlexGetConeSize(dm, support[sp], &coneSize);
203:     DMPlexGetCone(dm, support[sp], &cone);
204:     DMPlexGetConeOrientation(dm, support[sp], &coneO);
205:     for (cp = 0; cp < coneSize; ++cp) {
206:       if (cone[cp] != cell) continue;
207:       DMPlexInsertConeOrientation(dm, support[sp], cp, coneO[cp] >= 0 ? -(faceSize-coneO[cp]) : faceSize+coneO[cp]);
208:     }
209:   }
210:   DMRestoreWorkArray(dm, maxConeSize, MPIU_INT, &revcone);
211:   DMRestoreWorkArray(dm, maxConeSize, MPIU_INT, &revconeO);
212:   return(0);
213: }

215: /*
216:   - Checks face match
217:     - Flips non-matching
218:   - Inserts faces of support cells in FIFO
219: */
220: static PetscErrorCode DMPlexCheckFace_Internal(DM dm, PetscInt *faceFIFO, PetscInt *fTop, PetscInt *fBottom, PetscInt cStart, PetscInt fStart, PetscInt fEnd, PetscBT seenCells, PetscBT flippedCells, PetscBT seenFaces)
221: {
222:   const PetscInt *support, *coneA, *coneB, *coneOA, *coneOB;
223:   PetscInt        supportSize, coneSizeA, coneSizeB, posA = -1, posB = -1;
224:   PetscInt        face, dim, seenA, flippedA, seenB, flippedB, mismatch, c;
225:   PetscErrorCode  ierr;

228:   face = faceFIFO[(*fTop)++];
229:   DMGetDimension(dm, &dim);
230:   DMPlexGetSupportSize(dm, face, &supportSize);
231:   DMPlexGetSupport(dm, face, &support);
232:   if (supportSize < 2) return(0);
233:   if (supportSize != 2) SETERRQ1(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Faces should separate only two cells, not %d", supportSize);
234:   seenA    = PetscBTLookup(seenCells,    support[0]-cStart);
235:   flippedA = PetscBTLookup(flippedCells, support[0]-cStart) ? 1 : 0;
236:   seenB    = PetscBTLookup(seenCells,    support[1]-cStart);
237:   flippedB = PetscBTLookup(flippedCells, support[1]-cStart) ? 1 : 0;

239:   DMPlexGetConeSize(dm, support[0], &coneSizeA);
240:   DMPlexGetConeSize(dm, support[1], &coneSizeB);
241:   DMPlexGetCone(dm, support[0], &coneA);
242:   DMPlexGetCone(dm, support[1], &coneB);
243:   DMPlexGetConeOrientation(dm, support[0], &coneOA);
244:   DMPlexGetConeOrientation(dm, support[1], &coneOB);
245:   for (c = 0; c < coneSizeA; ++c) {
246:     if (!PetscBTLookup(seenFaces, coneA[c]-fStart)) {
247:       faceFIFO[(*fBottom)++] = coneA[c];
248:       PetscBTSet(seenFaces, coneA[c]-fStart);
249:     }
250:     if (coneA[c] == face) posA = c;
251:     if (*fBottom > fEnd-fStart) SETERRQ3(PETSC_COMM_SELF, PETSC_ERR_PLIB, "Face %d was pushed exceeding capacity %d > %d", coneA[c], *fBottom, fEnd-fStart);
252:   }
253:   if (posA < 0) SETERRQ2(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Face %d could not be located in cell %d", face, support[0]);
254:   for (c = 0; c < coneSizeB; ++c) {
255:     if (!PetscBTLookup(seenFaces, coneB[c]-fStart)) {
256:       faceFIFO[(*fBottom)++] = coneB[c];
257:       PetscBTSet(seenFaces, coneB[c]-fStart);
258:     }
259:     if (coneB[c] == face) posB = c;
260:     if (*fBottom > fEnd-fStart) SETERRQ3(PETSC_COMM_SELF, PETSC_ERR_PLIB, "Face %d was pushed exceeding capacity %d > %d", coneA[c], *fBottom, fEnd-fStart);
261:   }
262:   if (posB < 0) SETERRQ2(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Face %d could not be located in cell %d", face, support[1]);

264:   if (dim == 1) {
265:     mismatch = posA == posB;
266:   } else {
267:     mismatch = coneOA[posA] == coneOB[posB];
268:   }

270:   if (mismatch ^ (flippedA ^ flippedB)) {
271:     if (seenA && seenB) SETERRQ2(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Previously seen cells %d and %d do not match: Fault mesh is non-orientable", support[0], support[1]);
272:     if (!seenA && !flippedA) {
273:       PetscBTSet(flippedCells, support[0]-cStart);
274:     } else if (!seenB && !flippedB) {
275:       PetscBTSet(flippedCells, support[1]-cStart);
276:     } else SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Inconsistent mesh orientation: Fault mesh is non-orientable");
277:   } else if (mismatch && flippedA && flippedB) SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Attempt to flip already flipped cell: Fault mesh is non-orientable");
278:   PetscBTSet(seenCells, support[0]-cStart);
279:   PetscBTSet(seenCells, support[1]-cStart);
280:   return(0);
281: }

283: /*@
284:   DMPlexOrient - Give a consistent orientation to the input mesh

286:   Input Parameters:
287: . dm - The DM

289:   Note: The orientation data for the DM are change in-place.
290: $ This routine will fail for non-orientable surfaces, such as the Moebius strip.

292:   Level: advanced

294: .seealso: DMCreate(), DMPLEX
295: @*/
296: PetscErrorCode DMPlexOrient(DM dm)
297: {
298:   MPI_Comm           comm;
299:   PetscSF            sf;
300:   const PetscInt    *lpoints;
301:   const PetscSFNode *rpoints;
302:   PetscSFNode       *rorntComp = NULL, *lorntComp = NULL;
303:   PetscInt          *numNeighbors, **neighbors;
304:   PetscSFNode       *nrankComp;
305:   PetscBool         *match, *flipped;
306:   PetscBT            seenCells, flippedCells, seenFaces;
307:   PetscInt          *faceFIFO, fTop, fBottom, *cellComp, *faceComp;
308:   PetscInt           numLeaves, numRoots, dim, h, cStart, cEnd, c, cell, fStart, fEnd, face, off, totNeighbors = 0;
309:   PetscMPIInt        rank, size, numComponents, comp = 0;
310:   PetscBool          flg, flg2;
311:   PetscViewer        viewer = NULL, selfviewer = NULL;
312:   PetscErrorCode     ierr;

315:   PetscObjectGetComm((PetscObject) dm, &comm);
316:   MPI_Comm_rank(comm, &rank);
317:   MPI_Comm_size(comm, &size);
318:   PetscOptionsHasName(((PetscObject) dm)->options,((PetscObject) dm)->prefix, "-orientation_view", &flg);
319:   PetscOptionsHasName(((PetscObject) dm)->options,((PetscObject) dm)->prefix, "-orientation_view_synchronized", &flg2);
320:   DMGetPointSF(dm, &sf);
321:   PetscSFGetGraph(sf, &numRoots, &numLeaves, &lpoints, &rpoints);
322:   /* Truth Table
323:      mismatch    flips   do action   mismatch   flipA ^ flipB   action
324:          F       0 flips     no         F             F           F
325:          F       1 flip      yes        F             T           T
326:          F       2 flips     no         T             F           T
327:          T       0 flips     yes        T             T           F
328:          T       1 flip      no
329:          T       2 flips     yes
330:   */
331:   DMGetDimension(dm, &dim);
332:   DMPlexGetVTKCellHeight(dm, &h);
333:   DMPlexGetHeightStratum(dm, h,   &cStart, &cEnd);
334:   DMPlexGetHeightStratum(dm, h+1, &fStart, &fEnd);
335:   PetscBTCreate(cEnd - cStart, &seenCells);
336:   PetscBTMemzero(cEnd - cStart, seenCells);
337:   PetscBTCreate(cEnd - cStart, &flippedCells);
338:   PetscBTMemzero(cEnd - cStart, flippedCells);
339:   PetscBTCreate(fEnd - fStart, &seenFaces);
340:   PetscBTMemzero(fEnd - fStart, seenFaces);
341:   PetscCalloc3(fEnd - fStart, &faceFIFO, cEnd-cStart, &cellComp, fEnd-fStart, &faceComp);
342:   /*
343:    OLD STYLE
344:    - Add an integer array over cells and faces (component) for connected component number
345:    Foreach component
346:      - Mark the initial cell as seen
347:      - Process component as usual
348:      - Set component for all seenCells
349:      - Wipe seenCells and seenFaces (flippedCells can stay)
350:    - Generate parallel adjacency for component using SF and seenFaces
351:    - Collect numComponents adj data from each proc to 0
352:    - Build same serial graph
353:    - Use same solver
354:    - Use Scatterv to to send back flipped flags for each component
355:    - Negate flippedCells by component

357:    NEW STYLE
358:    - Create the adj on each process
359:    - Bootstrap to complete graph on proc 0
360:   */
361:   /* Loop over components */
362:   for (cell = cStart; cell < cEnd; ++cell) cellComp[cell-cStart] = -1;
363:   do {
364:     /* Look for first unmarked cell */
365:     for (cell = cStart; cell < cEnd; ++cell) if (cellComp[cell-cStart] < 0) break;
366:     if (cell >= cEnd) break;
367:     /* Initialize FIFO with first cell in component */
368:     {
369:       const PetscInt *cone;
370:       PetscInt        coneSize;

372:       fTop = fBottom = 0;
373:       DMPlexGetConeSize(dm, cell, &coneSize);
374:       DMPlexGetCone(dm, cell, &cone);
375:       for (c = 0; c < coneSize; ++c) {
376:         faceFIFO[fBottom++] = cone[c];
377:         PetscBTSet(seenFaces, cone[c]-fStart);
378:       }
379:       PetscBTSet(seenCells, cell-cStart);
380:     }
381:     /* Consider each face in FIFO */
382:     while (fTop < fBottom) {
383:       DMPlexCheckFace_Internal(dm, faceFIFO, &fTop, &fBottom, cStart, fStart, fEnd, seenCells, flippedCells, seenFaces);
384:     }
385:     /* Set component for cells and faces */
386:     for (cell = 0; cell < cEnd-cStart; ++cell) {
387:       if (PetscBTLookup(seenCells, cell)) cellComp[cell] = comp;
388:     }
389:     for (face = 0; face < fEnd-fStart; ++face) {
390:       if (PetscBTLookup(seenFaces, face)) faceComp[face] = comp;
391:     }
392:     /* Wipe seenCells and seenFaces for next component */
393:     PetscBTMemzero(fEnd - fStart, seenFaces);
394:     PetscBTMemzero(cEnd - cStart, seenCells);
395:     ++comp;
396:   } while (1);
397:   numComponents = comp;
398:   if (flg) {
399:     PetscViewer v;

401:     PetscViewerASCIIGetStdout(comm, &v);
402:     PetscViewerASCIIPushSynchronized(v);
403:     PetscViewerASCIISynchronizedPrintf(v, "[%d]BT for serial flipped cells:\n", rank);
404:     PetscBTView(cEnd-cStart, flippedCells, v);
405:     PetscViewerFlush(v);
406:     PetscViewerASCIIPopSynchronized(v);
407:   }
408:   /* Now all subdomains are oriented, but we need a consistent parallel orientation */
409:   if (numLeaves >= 0) {
410:     /* Store orientations of boundary faces*/
411:     PetscCalloc2(numRoots,&rorntComp,numRoots,&lorntComp);
412:     for (face = fStart; face < fEnd; ++face) {
413:       const PetscInt *cone, *support, *ornt;
414:       PetscInt        coneSize, supportSize;

416:       DMPlexGetSupportSize(dm, face, &supportSize);
417:       if (supportSize != 1) continue;
418:       DMPlexGetSupport(dm, face, &support);

420:       DMPlexGetCone(dm, support[0], &cone);
421:       DMPlexGetConeSize(dm, support[0], &coneSize);
422:       DMPlexGetConeOrientation(dm, support[0], &ornt);
423:       for (c = 0; c < coneSize; ++c) if (cone[c] == face) break;
424:       if (dim == 1) {
425:         /* Use cone position instead, shifted to -1 or 1 */
426:         if (PetscBTLookup(flippedCells, support[0]-cStart)) rorntComp[face].rank = 1-c*2;
427:         else                                                rorntComp[face].rank = c*2-1;
428:       } else {
429:         if (PetscBTLookup(flippedCells, support[0]-cStart)) rorntComp[face].rank = ornt[c] < 0 ? -1 :  1;
430:         else                                                rorntComp[face].rank = ornt[c] < 0 ?  1 : -1;
431:       }
432:       rorntComp[face].index = faceComp[face-fStart];
433:     }
434:     /* Communicate boundary edge orientations */
435:     PetscSFBcastBegin(sf, MPIU_2INT, rorntComp, lorntComp);
436:     PetscSFBcastEnd(sf, MPIU_2INT, rorntComp, lorntComp);
437:   }
438:   /* Get process adjacency */
439:   PetscMalloc2(numComponents, &numNeighbors, numComponents, &neighbors);
440:   viewer = PETSC_VIEWER_STDOUT_(PetscObjectComm((PetscObject)dm));
441:   if (flg2) {PetscViewerASCIIPushSynchronized(viewer);}
442:   PetscViewerGetSubViewer(viewer,PETSC_COMM_SELF,&selfviewer);
443:   for (comp = 0; comp < numComponents; ++comp) {
444:     PetscInt  l, n;

446:     numNeighbors[comp] = 0;
447:     PetscMalloc1(PetscMax(numLeaves, 0), &neighbors[comp]);
448:     /* I know this is p^2 time in general, but for bounded degree its alright */
449:     for (l = 0; l < numLeaves; ++l) {
450:       const PetscInt face = lpoints[l];

452:       /* Find a representative face (edge) separating pairs of procs */
453:       if ((face >= fStart) && (face < fEnd) && (faceComp[face-fStart] == comp)) {
454:         const PetscInt rrank = rpoints[l].rank;
455:         const PetscInt rcomp = lorntComp[face].index;

457:         for (n = 0; n < numNeighbors[comp]; ++n) if ((rrank == rpoints[neighbors[comp][n]].rank) && (rcomp == lorntComp[lpoints[neighbors[comp][n]]].index)) break;
458:         if (n >= numNeighbors[comp]) {
459:           PetscInt supportSize;

461:           DMPlexGetSupportSize(dm, face, &supportSize);
462:           if (supportSize != 1) SETERRQ1(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Boundary faces should see one cell, not %d", supportSize);
463:           if (flg) {PetscViewerASCIIPrintf(selfviewer, "[%d]: component %d, Found representative leaf %d (face %d) connecting to face %d on (%d, %d) with orientation %d\n", rank, comp, l, face, rpoints[l].index, rrank, rcomp, lorntComp[face].rank);}
464:           neighbors[comp][numNeighbors[comp]++] = l;
465:         }
466:       }
467:     }
468:     totNeighbors += numNeighbors[comp];
469:   }
470:   PetscViewerRestoreSubViewer(viewer,PETSC_COMM_SELF,&selfviewer);
471:   PetscViewerFlush(viewer);
472:   if (flg2) {PetscViewerASCIIPopSynchronized(viewer);}
473:   PetscMalloc2(totNeighbors, &nrankComp, totNeighbors, &match);
474:   for (comp = 0, off = 0; comp < numComponents; ++comp) {
475:     PetscInt n;

477:     for (n = 0; n < numNeighbors[comp]; ++n, ++off) {
478:       const PetscInt face = lpoints[neighbors[comp][n]];
479:       const PetscInt o    = rorntComp[face].rank*lorntComp[face].rank;

481:       if      (o < 0) match[off] = PETSC_TRUE;
482:       else if (o > 0) match[off] = PETSC_FALSE;
483:       else SETERRQ5(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Invalid face %d (%d, %d) neighbor: %d comp: %d", face, rorntComp[face], lorntComp[face], neighbors[comp][n], comp);
484:       nrankComp[off].rank  = rpoints[neighbors[comp][n]].rank;
485:       nrankComp[off].index = lorntComp[lpoints[neighbors[comp][n]]].index;
486:     }
487:     PetscFree(neighbors[comp]);
488:   }
489:   /* Collect the graph on 0 */
490:   if (numLeaves >= 0) {
491:     Mat          G;
492:     PetscBT      seenProcs, flippedProcs;
493:     PetscInt    *procFIFO, pTop, pBottom;
494:     PetscInt    *N   = NULL, *Noff;
495:     PetscSFNode *adj = NULL;
496:     PetscBool   *val = NULL;
497:     PetscMPIInt *recvcounts = NULL, *displs = NULL, *Nc, p, o;
498:     PetscMPIInt  size = 0;

500:     PetscCalloc1(numComponents, &flipped);
501:     if (!rank) {MPI_Comm_size(comm, &size);}
502:     PetscCalloc4(size, &recvcounts, size+1, &displs, size, &Nc, size+1, &Noff);
503:     MPI_Gather(&numComponents, 1, MPI_INT, Nc, 1, MPI_INT, 0, comm);
504:     for (p = 0; p < size; ++p) {
505:       displs[p+1] = displs[p] + Nc[p];
506:     }
507:     if (!rank) {PetscMalloc1(displs[size],&N);}
508:     MPI_Gatherv(numNeighbors, numComponents, MPIU_INT, N, Nc, displs, MPIU_INT, 0, comm);
509:     for (p = 0, o = 0; p < size; ++p) {
510:       recvcounts[p] = 0;
511:       for (c = 0; c < Nc[p]; ++c, ++o) recvcounts[p] += N[o];
512:       displs[p+1] = displs[p] + recvcounts[p];
513:     }
514:     if (!rank) {PetscMalloc2(displs[size], &adj, displs[size], &val);}
515:     MPI_Gatherv(nrankComp, totNeighbors, MPIU_2INT, adj, recvcounts, displs, MPIU_2INT, 0, comm);
516:     MPI_Gatherv(match, totNeighbors, MPIU_BOOL, val, recvcounts, displs, MPIU_BOOL, 0, comm);
517:     PetscFree2(numNeighbors, neighbors);
518:     if (!rank) {
519:       for (p = 1; p <= size; ++p) {Noff[p] = Noff[p-1] + Nc[p-1];}
520:       if (flg) {
521:         PetscInt n;

523:         for (p = 0, off = 0; p < size; ++p) {
524:           for (c = 0; c < Nc[p]; ++c) {
525:             PetscPrintf(PETSC_COMM_SELF, "Proc %d Comp %d:\n", p, c);
526:             for (n = 0; n < N[Noff[p]+c]; ++n, ++off) {
527:               PetscPrintf(PETSC_COMM_SELF, "  edge (%d, %d) (%d):\n", adj[off].rank, adj[off].index, val[off]);
528:             }
529:           }
530:         }
531:       }
532:       /* Symmetrize the graph */
533:       MatCreate(PETSC_COMM_SELF, &G);
534:       MatSetSizes(G, Noff[size], Noff[size], Noff[size], Noff[size]);
535:       MatSetUp(G);
536:       for (p = 0, off = 0; p < size; ++p) {
537:         for (c = 0; c < Nc[p]; ++c) {
538:           const PetscInt r = Noff[p]+c;
539:           PetscInt       n;

541:           for (n = 0; n < N[r]; ++n, ++off) {
542:             const PetscInt    q = Noff[adj[off].rank] + adj[off].index;
543:             const PetscScalar o = val[off] ? 1.0 : 0.0;

545:             MatSetValues(G, 1, &r, 1, &q, &o, INSERT_VALUES);
546:             MatSetValues(G, 1, &q, 1, &r, &o, INSERT_VALUES);
547:           }
548:         }
549:       }
550:       MatAssemblyBegin(G, MAT_FINAL_ASSEMBLY);
551:       MatAssemblyEnd(G, MAT_FINAL_ASSEMBLY);

553:       PetscBTCreate(Noff[size], &seenProcs);
554:       PetscBTMemzero(Noff[size], seenProcs);
555:       PetscBTCreate(Noff[size], &flippedProcs);
556:       PetscBTMemzero(Noff[size], flippedProcs);
557:       PetscMalloc1(Noff[size], &procFIFO);
558:       pTop = pBottom = 0;
559:       for (p = 0; p < Noff[size]; ++p) {
560:         if (PetscBTLookup(seenProcs, p)) continue;
561:         /* Initialize FIFO with next proc */
562:         procFIFO[pBottom++] = p;
563:         PetscBTSet(seenProcs, p);
564:         /* Consider each proc in FIFO */
565:         while (pTop < pBottom) {
566:           const PetscScalar *ornt;
567:           const PetscInt    *neighbors;
568:           PetscInt           proc, nproc, seen, flippedA, flippedB, mismatch, numNeighbors, n;

570:           proc     = procFIFO[pTop++];
571:           flippedA = PetscBTLookup(flippedProcs, proc) ? 1 : 0;
572:           MatGetRow(G, proc, &numNeighbors, &neighbors, &ornt);
573:           /* Loop over neighboring procs */
574:           for (n = 0; n < numNeighbors; ++n) {
575:             nproc    = neighbors[n];
576:             mismatch = PetscRealPart(ornt[n]) > 0.5 ? 0 : 1;
577:             seen     = PetscBTLookup(seenProcs, nproc);
578:             flippedB = PetscBTLookup(flippedProcs, nproc) ? 1 : 0;

580:             if (mismatch ^ (flippedA ^ flippedB)) {
581:               if (seen) SETERRQ2(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Previously seen procs %d and %d do not match: Fault mesh is non-orientable", proc, nproc);
582:               if (!flippedB) {
583:                 PetscBTSet(flippedProcs, nproc);
584:               } else SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Inconsistent mesh orientation: Fault mesh is non-orientable");
585:             } else if (mismatch && flippedA && flippedB) SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Attempt to flip already flipped cell: Fault mesh is non-orientable");
586:             if (!seen) {
587:               procFIFO[pBottom++] = nproc;
588:               PetscBTSet(seenProcs, nproc);
589:             }
590:           }
591:         }
592:       }
593:       PetscFree(procFIFO);
594:       MatDestroy(&G);
595:       PetscFree2(adj, val);
596:       PetscBTDestroy(&seenProcs);
597:     }
598:     /* Scatter flip flags */
599:     {
600:       PetscBool *flips = NULL;

602:       if (!rank) {
603:         PetscMalloc1(Noff[size], &flips);
604:         for (p = 0; p < Noff[size]; ++p) {
605:           flips[p] = PetscBTLookup(flippedProcs, p) ? PETSC_TRUE : PETSC_FALSE;
606:           if (flg && flips[p]) {PetscPrintf(comm, "Flipping Proc+Comp %d:\n", p);}
607:         }
608:         for (p = 0; p < size; ++p) {
609:           displs[p+1] = displs[p] + Nc[p];
610:         }
611:       }
612:       MPI_Scatterv(flips, Nc, displs, MPIU_BOOL, flipped, numComponents, MPIU_BOOL, 0, comm);
613:       PetscFree(flips);
614:     }
615:     if (!rank) {PetscBTDestroy(&flippedProcs);}
616:     PetscFree(N);
617:     PetscFree4(recvcounts, displs, Nc, Noff);
618:     PetscFree2(nrankComp, match);

620:     /* Decide whether to flip cells in each component */
621:     for (c = 0; c < cEnd-cStart; ++c) {if (flipped[cellComp[c]]) {PetscBTNegate(flippedCells, c);}}
622:     PetscFree(flipped);
623:   }
624:   if (flg) {
625:     PetscViewer v;

627:     PetscViewerASCIIGetStdout(comm, &v);
628:     PetscViewerASCIIPushSynchronized(v);
629:     PetscViewerASCIISynchronizedPrintf(v, "[%d]BT for parallel flipped cells:\n", rank);
630:     PetscBTView(cEnd-cStart, flippedCells, v);
631:     PetscViewerFlush(v);
632:     PetscViewerASCIIPopSynchronized(v);
633:   }
634:   /* Reverse flipped cells in the mesh */
635:   for (c = cStart; c < cEnd; ++c) {
636:     if (PetscBTLookup(flippedCells, c-cStart)) {
637:       DMPlexReverseCell(dm, c);
638:     }
639:   }
640:   PetscBTDestroy(&seenCells);
641:   PetscBTDestroy(&flippedCells);
642:   PetscBTDestroy(&seenFaces);
643:   PetscFree2(numNeighbors, neighbors);
644:   PetscFree2(rorntComp, lorntComp);
645:   PetscFree3(faceFIFO, cellComp, faceComp);
646:   return(0);
647: }