xref: /petsc/src/dm/impls/plex/plexdistribute.c (revision 7bdf51c94ab34bb5ee23d1e71be7a8794867c0b9)
1 #include <petsc/private/dmpleximpl.h>    /*I      "petscdmplex.h"   I*/
2 #include <petsc/private/dmlabelimpl.h>   /*I      "petscdmlabel.h"  I*/
3 
4 /*@C
5   DMPlexSetAdjacencyUser - Define adjacency in the mesh using a user-provided callback
6 
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
11 
12   Level: advanced
13 
14   Notes:
15      The caller of DMPlexGetAdjacency may need to arrange that a large enough array is available for the adjacency.
16 
17      Any setting here overrides other configuration of DMPlex adjacency determination.
18 
19 .seealso: DMPlexSetAdjacencyUseCone(), DMPlexSetAdjacencyUseClosure(), 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;
24 
25   PetscFunctionBegin;
26   PetscValidHeaderSpecific(dm, DM_CLASSID, 1);
27   mesh->useradjacency = user;
28   mesh->useradjacencyctx = ctx;
29   PetscFunctionReturn(0);
30 }
31 
32 /*@C
33   DMPlexGetAdjacencyUser - get the user-defined adjacency callback
34 
35   Input Parameter:
36 . dm      - The DM object
37 
38   Output Parameters:
39 - user    - The user callback
40 - ctx     - context for callback evaluation
41 
42   Level: advanced
43 
44 .seealso: DMPlexSetAdjacencyUseCone(), DMPlexSetAdjacencyUseClosure(), 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;
49 
50   PetscFunctionBegin;
51   PetscValidHeaderSpecific(dm, DM_CLASSID, 1);
52   if (user) *user = mesh->useradjacency;
53   if (ctx) *ctx = mesh->useradjacencyctx;
54   PetscFunctionReturn(0);
55 }
56 
57 /*@
58   DMPlexSetAdjacencyUseCone - Define adjacency in the mesh using either the cone or the support first
59 
60   Input Parameters:
61 + dm      - The DM object
62 - useCone - Flag to use the cone first
63 
64   Level: intermediate
65 
66   Notes:
67 $     FEM:   Two points p and q are adjacent if q \in closure(star(p)),   useCone = PETSC_FALSE, useClosure = PETSC_TRUE
68 $     FVM:   Two points p and q are adjacent if q \in support(p+cone(p)), useCone = PETSC_TRUE,  useClosure = PETSC_FALSE
69 $     FVM++: Two points p and q are adjacent if q \in star(closure(p)),   useCone = PETSC_TRUE,  useClosure = PETSC_TRUE
70 
71 .seealso: DMPlexGetAdjacencyUseCone(), DMPlexSetAdjacencyUseClosure(), DMPlexGetAdjacencyUseClosure(), DMPlexDistribute(), DMPlexPreallocateOperator()
72 @*/
73 PetscErrorCode DMPlexSetAdjacencyUseCone(DM dm, PetscBool useCone)
74 {
75   PetscDS        prob;
76   PetscBool      useClosure;
77   PetscInt       Nf;
78   PetscErrorCode ierr;
79 
80   PetscFunctionBegin;
81   ierr = DMGetDS(dm, &prob);CHKERRQ(ierr);
82   ierr = PetscDSGetNumFields(prob, &Nf);CHKERRQ(ierr);
83   if (!Nf) {
84     ierr = PetscDSGetAdjacency(prob, PETSC_DEFAULT, NULL, &useClosure);CHKERRQ(ierr);
85     ierr = PetscDSSetAdjacency(prob, PETSC_DEFAULT, useCone, useClosure);CHKERRQ(ierr);
86   } else {
87     ierr = PetscDSGetAdjacency(prob, 0, NULL, &useClosure);CHKERRQ(ierr);
88     ierr = PetscDSSetAdjacency(prob, 0, useCone, useClosure);CHKERRQ(ierr);
89   }
90   PetscFunctionReturn(0);
91 }
92 
93 /*@
94   DMPlexGetAdjacencyUseCone - Query whether adjacency in the mesh uses the cone or the support first
95 
96   Input Parameter:
97 . dm      - The DM object
98 
99   Output Parameter:
100 . useCone - Flag to use the cone first
101 
102   Level: intermediate
103 
104   Notes:
105 $     FEM:   Two points p and q are adjacent if q \in closure(star(p)),   useCone = PETSC_FALSE, useClosure = PETSC_TRUE
106 $     FVM:   Two points p and q are adjacent if q \in support(p+cone(p)), useCone = PETSC_TRUE,  useClosure = PETSC_FALSE
107 $     FVM++: Two points p and q are adjacent if q \in star(closure(p)),   useCone = PETSC_TRUE,  useClosure = PETSC_TRUE
108 
109 .seealso: DMPlexSetAdjacencyUseCone(), DMPlexSetAdjacencyUseClosure(), DMPlexGetAdjacencyUseClosure(), DMPlexDistribute(), DMPlexPreallocateOperator()
110 @*/
111 PetscErrorCode DMPlexGetAdjacencyUseCone(DM dm, PetscBool *useCone)
112 {
113   PetscDS        prob;
114   PetscInt       Nf;
115   PetscErrorCode ierr;
116 
117   PetscFunctionBegin;
118   ierr = DMGetDS(dm, &prob);CHKERRQ(ierr);
119   ierr = PetscDSGetNumFields(prob, &Nf);CHKERRQ(ierr);
120   if (!Nf) {
121     ierr = PetscDSGetAdjacency(prob, PETSC_DEFAULT, useCone, NULL);CHKERRQ(ierr);
122   } else {
123     ierr = PetscDSGetAdjacency(prob, 0, useCone, NULL);CHKERRQ(ierr);
124   }
125   PetscFunctionReturn(0);
126 }
127 
128 /*@
129   DMPlexSetAdjacencyUseClosure - Define adjacency in the mesh using the transitive closure
130 
131   Input Parameters:
132 + dm      - The DM object
133 - useClosure - Flag to use the closure
134 
135   Level: intermediate
136 
137   Notes:
138 $     FEM:   Two points p and q are adjacent if q \in closure(star(p)),   useCone = PETSC_FALSE, useClosure = PETSC_TRUE
139 $     FVM:   Two points p and q are adjacent if q \in support(p+cone(p)), useCone = PETSC_TRUE,  useClosure = PETSC_FALSE
140 $     FVM++: Two points p and q are adjacent if q \in star(closure(p)),   useCone = PETSC_TRUE,  useClosure = PETSC_TRUE
141 
142 .seealso: DMPlexGetAdjacencyUseClosure(), DMPlexSetAdjacencyUseCone(), DMPlexGetAdjacencyUseCone(), DMPlexDistribute(), DMPlexPreallocateOperator()
143 @*/
144 PetscErrorCode DMPlexSetAdjacencyUseClosure(DM dm, PetscBool useClosure)
145 {
146   PetscDS        prob;
147   PetscBool      useCone;
148   PetscInt       Nf;
149   PetscErrorCode ierr;
150 
151   PetscFunctionBegin;
152   ierr = DMGetDS(dm, &prob);CHKERRQ(ierr);
153   ierr = PetscDSGetNumFields(prob, &Nf);CHKERRQ(ierr);
154   if (!Nf) {
155     ierr = PetscDSGetAdjacency(prob, PETSC_DEFAULT, &useCone, NULL);CHKERRQ(ierr);
156     ierr = PetscDSSetAdjacency(prob, PETSC_DEFAULT, useCone, useClosure);CHKERRQ(ierr);
157   } else {
158     ierr = PetscDSGetAdjacency(prob, 0, &useCone, NULL);CHKERRQ(ierr);
159     ierr = PetscDSSetAdjacency(prob, 0, useCone, useClosure);CHKERRQ(ierr);
160   }
161   PetscFunctionReturn(0);
162 }
163 
164 /*@
165   DMPlexGetAdjacencyUseClosure - Query whether adjacency in the mesh uses the transitive closure
166 
167   Input Parameter:
168 . dm      - The DM object
169 
170   Output Parameter:
171 . useClosure - Flag to use the closure
172 
173   Level: intermediate
174 
175   Notes:
176 $     FEM:   Two points p and q are adjacent if q \in closure(star(p)),   useCone = PETSC_FALSE, useClosure = PETSC_TRUE
177 $     FVM:   Two points p and q are adjacent if q \in support(p+cone(p)), useCone = PETSC_TRUE,  useClosure = PETSC_FALSE
178 $     FVM++: Two points p and q are adjacent if q \in star(closure(p)),   useCone = PETSC_TRUE,  useClosure = PETSC_TRUE
179 
180 .seealso: DMPlexSetAdjacencyUseClosure(), DMPlexSetAdjacencyUseCone(), DMPlexGetAdjacencyUseCone(), DMPlexDistribute(), DMPlexPreallocateOperator()
181 @*/
182 PetscErrorCode DMPlexGetAdjacencyUseClosure(DM dm, PetscBool *useClosure)
183 {
184   PetscDS        prob;
185   PetscInt       Nf;
186   PetscErrorCode ierr;
187 
188   PetscFunctionBegin;
189   ierr = DMGetDS(dm, &prob);CHKERRQ(ierr);
190   ierr = PetscDSGetNumFields(prob, &Nf);CHKERRQ(ierr);
191   if (!Nf) {
192     ierr = PetscDSGetAdjacency(prob, PETSC_DEFAULT, NULL, useClosure);CHKERRQ(ierr);
193   } else {
194     ierr = PetscDSGetAdjacency(prob, 0, NULL, useClosure);CHKERRQ(ierr);
195   }
196   PetscFunctionReturn(0);
197 }
198 
199 /*@
200   DMPlexSetAdjacencyUseAnchors - Define adjacency in the mesh using the point-to-point constraints.
201 
202   Input Parameters:
203 + dm      - The DM object
204 - useAnchors - Flag to use the constraints.  If PETSC_TRUE, then constrained points are omitted from DMPlexGetAdjacency(), and their anchor points appear in their place.
205 
206   Level: intermediate
207 
208 .seealso: DMPlexGetAdjacencyUseClosure(), DMPlexSetAdjacencyUseCone(), DMPlexGetAdjacencyUseCone(), DMPlexDistribute(), DMPlexPreallocateOperator(), DMPlexSetAnchors()
209 @*/
210 PetscErrorCode DMPlexSetAdjacencyUseAnchors(DM dm, PetscBool useAnchors)
211 {
212   DM_Plex *mesh = (DM_Plex *) dm->data;
213 
214   PetscFunctionBegin;
215   PetscValidHeaderSpecific(dm, DM_CLASSID, 1);
216   mesh->useAnchors = useAnchors;
217   PetscFunctionReturn(0);
218 }
219 
220 /*@
221   DMPlexGetAdjacencyUseAnchors - Query whether adjacency in the mesh uses the point-to-point constraints.
222 
223   Input Parameter:
224 . dm      - The DM object
225 
226   Output Parameter:
227 . useAnchors - Flag to use the closure.  If PETSC_TRUE, then constrained points are omitted from DMPlexGetAdjacency(), and their anchor points appear in their place.
228 
229   Level: intermediate
230 
231 .seealso: DMPlexSetAdjacencyUseAnchors(), DMPlexSetAdjacencyUseCone(), DMPlexGetAdjacencyUseCone(), DMPlexDistribute(), DMPlexPreallocateOperator(), DMPlexSetAnchors()
232 @*/
233 PetscErrorCode DMPlexGetAdjacencyUseAnchors(DM dm, PetscBool *useAnchors)
234 {
235   DM_Plex *mesh = (DM_Plex *) dm->data;
236 
237   PetscFunctionBegin;
238   PetscValidHeaderSpecific(dm, DM_CLASSID, 1);
239   PetscValidIntPointer(useAnchors, 2);
240   *useAnchors = mesh->useAnchors;
241   PetscFunctionReturn(0);
242 }
243 
244 static PetscErrorCode DMPlexGetAdjacency_Cone_Internal(DM dm, PetscInt p, PetscInt *adjSize, PetscInt adj[])
245 {
246   const PetscInt *cone = NULL;
247   PetscInt        numAdj = 0, maxAdjSize = *adjSize, coneSize, c;
248   PetscErrorCode  ierr;
249 
250   PetscFunctionBeginHot;
251   ierr = DMPlexGetConeSize(dm, p, &coneSize);CHKERRQ(ierr);
252   ierr = DMPlexGetCone(dm, p, &cone);CHKERRQ(ierr);
253   for (c = 0; c <= coneSize; ++c) {
254     const PetscInt  point   = !c ? p : cone[c-1];
255     const PetscInt *support = NULL;
256     PetscInt        supportSize, s, q;
257 
258     ierr = DMPlexGetSupportSize(dm, point, &supportSize);CHKERRQ(ierr);
259     ierr = DMPlexGetSupport(dm, point, &support);CHKERRQ(ierr);
260     for (s = 0; s < supportSize; ++s) {
261       for (q = 0; q < numAdj || ((void)(adj[numAdj++] = support[s]),0); ++q) {
262         if (support[s] == adj[q]) break;
263       }
264       if (numAdj > maxAdjSize) SETERRQ1(PETSC_COMM_SELF, PETSC_ERR_PLIB, "Invalid mesh exceeded adjacency allocation (%D)", maxAdjSize);
265     }
266   }
267   *adjSize = numAdj;
268   PetscFunctionReturn(0);
269 }
270 
271 static PetscErrorCode DMPlexGetAdjacency_Support_Internal(DM dm, PetscInt p, PetscInt *adjSize, PetscInt adj[])
272 {
273   const PetscInt *support = NULL;
274   PetscInt        numAdj   = 0, maxAdjSize = *adjSize, supportSize, s;
275   PetscErrorCode  ierr;
276 
277   PetscFunctionBeginHot;
278   ierr = DMPlexGetSupportSize(dm, p, &supportSize);CHKERRQ(ierr);
279   ierr = DMPlexGetSupport(dm, p, &support);CHKERRQ(ierr);
280   for (s = 0; s <= supportSize; ++s) {
281     const PetscInt  point = !s ? p : support[s-1];
282     const PetscInt *cone  = NULL;
283     PetscInt        coneSize, c, q;
284 
285     ierr = DMPlexGetConeSize(dm, point, &coneSize);CHKERRQ(ierr);
286     ierr = DMPlexGetCone(dm, point, &cone);CHKERRQ(ierr);
287     for (c = 0; c < coneSize; ++c) {
288       for (q = 0; q < numAdj || ((void)(adj[numAdj++] = cone[c]),0); ++q) {
289         if (cone[c] == adj[q]) break;
290       }
291       if (numAdj > maxAdjSize) SETERRQ1(PETSC_COMM_SELF, PETSC_ERR_PLIB, "Invalid mesh exceeded adjacency allocation (%D)", maxAdjSize);
292     }
293   }
294   *adjSize = numAdj;
295   PetscFunctionReturn(0);
296 }
297 
298 static PetscErrorCode DMPlexGetAdjacency_Transitive_Internal(DM dm, PetscInt p, PetscBool useClosure, PetscInt *adjSize, PetscInt adj[])
299 {
300   PetscInt      *star = NULL;
301   PetscInt       numAdj = 0, maxAdjSize = *adjSize, starSize, s;
302   PetscErrorCode ierr;
303 
304   PetscFunctionBeginHot;
305   ierr = DMPlexGetTransitiveClosure(dm, p, useClosure, &starSize, &star);CHKERRQ(ierr);
306   for (s = 0; s < starSize*2; s += 2) {
307     const PetscInt *closure = NULL;
308     PetscInt        closureSize, c, q;
309 
310     ierr = DMPlexGetTransitiveClosure(dm, star[s], (PetscBool)!useClosure, &closureSize, (PetscInt**) &closure);CHKERRQ(ierr);
311     for (c = 0; c < closureSize*2; c += 2) {
312       for (q = 0; q < numAdj || ((void)(adj[numAdj++] = closure[c]),0); ++q) {
313         if (closure[c] == adj[q]) break;
314       }
315       if (numAdj > maxAdjSize) SETERRQ1(PETSC_COMM_SELF, PETSC_ERR_PLIB, "Invalid mesh exceeded adjacency allocation (%D)", maxAdjSize);
316     }
317     ierr = DMPlexRestoreTransitiveClosure(dm, star[s], (PetscBool)!useClosure, &closureSize, (PetscInt**) &closure);CHKERRQ(ierr);
318   }
319   ierr = DMPlexRestoreTransitiveClosure(dm, p, useClosure, &starSize, &star);CHKERRQ(ierr);
320   *adjSize = numAdj;
321   PetscFunctionReturn(0);
322 }
323 
324 PetscErrorCode DMPlexGetAdjacency_Internal(DM dm, PetscInt p, PetscBool useCone, PetscBool useTransitiveClosure, PetscBool useAnchors, PetscInt *adjSize, PetscInt *adj[])
325 {
326   static PetscInt asiz = 0;
327   PetscInt maxAnchors = 1;
328   PetscInt aStart = -1, aEnd = -1;
329   PetscInt maxAdjSize;
330   PetscSection aSec = NULL;
331   IS aIS = NULL;
332   const PetscInt *anchors;
333   DM_Plex *mesh = (DM_Plex *)dm->data;
334   PetscErrorCode  ierr;
335 
336   PetscFunctionBeginHot;
337   if (useAnchors) {
338     ierr = DMPlexGetAnchors(dm,&aSec,&aIS);CHKERRQ(ierr);
339     if (aSec) {
340       ierr = PetscSectionGetMaxDof(aSec,&maxAnchors);CHKERRQ(ierr);
341       maxAnchors = PetscMax(1,maxAnchors);
342       ierr = PetscSectionGetChart(aSec,&aStart,&aEnd);CHKERRQ(ierr);
343       ierr = ISGetIndices(aIS,&anchors);CHKERRQ(ierr);
344     }
345   }
346   if (!*adj) {
347     PetscInt depth, coneSeries, supportSeries, maxC, maxS, pStart, pEnd;
348 
349     ierr  = DMPlexGetChart(dm, &pStart,&pEnd);CHKERRQ(ierr);
350     ierr  = DMPlexGetDepth(dm, &depth);CHKERRQ(ierr);
351     ierr  = DMPlexGetMaxSizes(dm, &maxC, &maxS);CHKERRQ(ierr);
352     coneSeries    = (maxC > 1) ? ((PetscPowInt(maxC,depth+1)-1)/(maxC-1)) : depth+1;
353     supportSeries = (maxS > 1) ? ((PetscPowInt(maxS,depth+1)-1)/(maxS-1)) : depth+1;
354     asiz  = PetscMax(PetscPowInt(maxS,depth)*coneSeries,PetscPowInt(maxC,depth)*supportSeries);
355     asiz *= maxAnchors;
356     asiz  = PetscMin(asiz,pEnd-pStart);
357     ierr  = PetscMalloc1(asiz,adj);CHKERRQ(ierr);
358   }
359   if (*adjSize < 0) *adjSize = asiz;
360   maxAdjSize = *adjSize;
361   if (mesh->useradjacency) {
362     ierr = mesh->useradjacency(dm, p, adjSize, *adj, mesh->useradjacencyctx);CHKERRQ(ierr);
363   } else if (useTransitiveClosure) {
364     ierr = DMPlexGetAdjacency_Transitive_Internal(dm, p, useCone, adjSize, *adj);CHKERRQ(ierr);
365   } else if (useCone) {
366     ierr = DMPlexGetAdjacency_Cone_Internal(dm, p, adjSize, *adj);CHKERRQ(ierr);
367   } else {
368     ierr = DMPlexGetAdjacency_Support_Internal(dm, p, adjSize, *adj);CHKERRQ(ierr);
369   }
370   if (useAnchors && aSec) {
371     PetscInt origSize = *adjSize;
372     PetscInt numAdj = origSize;
373     PetscInt i = 0, j;
374     PetscInt *orig = *adj;
375 
376     while (i < origSize) {
377       PetscInt p = orig[i];
378       PetscInt aDof = 0;
379 
380       if (p >= aStart && p < aEnd) {
381         ierr = PetscSectionGetDof(aSec,p,&aDof);CHKERRQ(ierr);
382       }
383       if (aDof) {
384         PetscInt aOff;
385         PetscInt s, q;
386 
387         for (j = i + 1; j < numAdj; j++) {
388           orig[j - 1] = orig[j];
389         }
390         origSize--;
391         numAdj--;
392         ierr = PetscSectionGetOffset(aSec,p,&aOff);CHKERRQ(ierr);
393         for (s = 0; s < aDof; ++s) {
394           for (q = 0; q < numAdj || ((void)(orig[numAdj++] = anchors[aOff+s]),0); ++q) {
395             if (anchors[aOff+s] == orig[q]) break;
396           }
397           if (numAdj > maxAdjSize) SETERRQ1(PETSC_COMM_SELF, PETSC_ERR_PLIB, "Invalid mesh exceeded adjacency allocation (%D)", maxAdjSize);
398         }
399       }
400       else {
401         i++;
402       }
403     }
404     *adjSize = numAdj;
405     ierr = ISRestoreIndices(aIS,&anchors);CHKERRQ(ierr);
406   }
407   PetscFunctionReturn(0);
408 }
409 
410 /*@
411   DMPlexGetAdjacency - Return all points adjacent to the given point
412 
413   Input Parameters:
414 + dm - The DM object
415 . p  - The point
416 . adjSize - The maximum size of adj if it is non-NULL, or PETSC_DETERMINE
417 - adj - Either NULL so that the array is allocated, or an existing array with size adjSize
418 
419   Output Parameters:
420 + adjSize - The number of adjacent points
421 - adj - The adjacent points
422 
423   Level: advanced
424 
425   Notes: The user must PetscFree the adj array if it was not passed in.
426 
427 .seealso: DMPlexSetAdjacencyUseCone(), DMPlexSetAdjacencyUseClosure(), DMPlexDistribute(), DMCreateMatrix(), DMPlexPreallocateOperator()
428 @*/
429 PetscErrorCode DMPlexGetAdjacency(DM dm, PetscInt p, PetscInt *adjSize, PetscInt *adj[])
430 {
431   PetscBool      useCone, useClosure, useAnchors;
432   PetscErrorCode ierr;
433 
434   PetscFunctionBeginHot;
435   PetscValidHeaderSpecific(dm, DM_CLASSID, 1);
436   PetscValidPointer(adjSize,3);
437   PetscValidPointer(adj,4);
438   ierr = DMPlexGetAdjacencyUseCone(dm, &useCone);CHKERRQ(ierr);
439   ierr = DMPlexGetAdjacencyUseClosure(dm, &useClosure);CHKERRQ(ierr);
440   ierr = DMPlexGetAdjacencyUseAnchors(dm, &useAnchors);CHKERRQ(ierr);
441   ierr = DMPlexGetAdjacency_Internal(dm, p, useCone, useClosure, useAnchors, adjSize, adj);CHKERRQ(ierr);
442   PetscFunctionReturn(0);
443 }
444 
445 /*@
446   DMPlexCreateTwoSidedProcessSF - Create an SF which just has process connectivity
447 
448   Collective on DM
449 
450   Input Parameters:
451 + dm      - The DM
452 - sfPoint - The PetscSF which encodes point connectivity
453 
454   Output Parameters:
455 + processRanks - A list of process neighbors, or NULL
456 - sfProcess    - An SF encoding the two-sided process connectivity, or NULL
457 
458   Level: developer
459 
460 .seealso: PetscSFCreate(), DMPlexCreateProcessSF()
461 @*/
462 PetscErrorCode DMPlexCreateTwoSidedProcessSF(DM dm, PetscSF sfPoint, PetscSection rootRankSection, IS rootRanks, PetscSection leafRankSection, IS leafRanks, IS *processRanks, PetscSF *sfProcess)
463 {
464   const PetscSFNode *remotePoints;
465   PetscInt          *localPointsNew;
466   PetscSFNode       *remotePointsNew;
467   const PetscInt    *nranks;
468   PetscInt          *ranksNew;
469   PetscBT            neighbors;
470   PetscInt           pStart, pEnd, p, numLeaves, l, numNeighbors, n;
471   PetscMPIInt        size, proc, rank;
472   PetscErrorCode     ierr;
473 
474   PetscFunctionBegin;
475   PetscValidHeaderSpecific(dm, DM_CLASSID, 1);
476   PetscValidHeaderSpecific(sfPoint, PETSCSF_CLASSID, 2);
477   if (processRanks) {PetscValidPointer(processRanks, 3);}
478   if (sfProcess)    {PetscValidPointer(sfProcess, 4);}
479   ierr = MPI_Comm_size(PetscObjectComm((PetscObject) dm), &size);CHKERRQ(ierr);
480   ierr = MPI_Comm_rank(PetscObjectComm((PetscObject) dm), &rank);CHKERRQ(ierr);
481   ierr = PetscSFGetGraph(sfPoint, NULL, &numLeaves, NULL, &remotePoints);CHKERRQ(ierr);
482   ierr = PetscBTCreate(size, &neighbors);CHKERRQ(ierr);
483   ierr = PetscBTMemzero(size, neighbors);CHKERRQ(ierr);
484   /* Compute root-to-leaf process connectivity */
485   ierr = PetscSectionGetChart(rootRankSection, &pStart, &pEnd);CHKERRQ(ierr);
486   ierr = ISGetIndices(rootRanks, &nranks);CHKERRQ(ierr);
487   for (p = pStart; p < pEnd; ++p) {
488     PetscInt ndof, noff, n;
489 
490     ierr = PetscSectionGetDof(rootRankSection, p, &ndof);CHKERRQ(ierr);
491     ierr = PetscSectionGetOffset(rootRankSection, p, &noff);CHKERRQ(ierr);
492     for (n = 0; n < ndof; ++n) {ierr = PetscBTSet(neighbors, nranks[noff+n]);CHKERRQ(ierr);}
493   }
494   ierr = ISRestoreIndices(rootRanks, &nranks);CHKERRQ(ierr);
495   /* Compute leaf-to-neighbor process connectivity */
496   ierr = PetscSectionGetChart(leafRankSection, &pStart, &pEnd);CHKERRQ(ierr);
497   ierr = ISGetIndices(leafRanks, &nranks);CHKERRQ(ierr);
498   for (p = pStart; p < pEnd; ++p) {
499     PetscInt ndof, noff, n;
500 
501     ierr = PetscSectionGetDof(leafRankSection, p, &ndof);CHKERRQ(ierr);
502     ierr = PetscSectionGetOffset(leafRankSection, p, &noff);CHKERRQ(ierr);
503     for (n = 0; n < ndof; ++n) {ierr = PetscBTSet(neighbors, nranks[noff+n]);CHKERRQ(ierr);}
504   }
505   ierr = ISRestoreIndices(leafRanks, &nranks);CHKERRQ(ierr);
506   /* Compute leaf-to-root process connectivity */
507   for (l = 0; l < numLeaves; ++l) {PetscBTSet(neighbors, remotePoints[l].rank);}
508   /* Calculate edges */
509   PetscBTClear(neighbors, rank);
510   for(proc = 0, numNeighbors = 0; proc < size; ++proc) {if (PetscBTLookup(neighbors, proc)) ++numNeighbors;}
511   ierr = PetscMalloc1(numNeighbors, &ranksNew);CHKERRQ(ierr);
512   ierr = PetscMalloc1(numNeighbors, &localPointsNew);CHKERRQ(ierr);
513   ierr = PetscMalloc1(numNeighbors, &remotePointsNew);CHKERRQ(ierr);
514   for(proc = 0, n = 0; proc < size; ++proc) {
515     if (PetscBTLookup(neighbors, proc)) {
516       ranksNew[n]              = proc;
517       localPointsNew[n]        = proc;
518       remotePointsNew[n].index = rank;
519       remotePointsNew[n].rank  = proc;
520       ++n;
521     }
522   }
523   ierr = PetscBTDestroy(&neighbors);CHKERRQ(ierr);
524   if (processRanks) {ierr = ISCreateGeneral(PetscObjectComm((PetscObject)dm), numNeighbors, ranksNew, PETSC_OWN_POINTER, processRanks);CHKERRQ(ierr);}
525   else              {ierr = PetscFree(ranksNew);CHKERRQ(ierr);}
526   if (sfProcess) {
527     ierr = PetscSFCreate(PetscObjectComm((PetscObject)dm), sfProcess);CHKERRQ(ierr);
528     ierr = PetscObjectSetName((PetscObject) *sfProcess, "Two-Sided Process SF");CHKERRQ(ierr);
529     ierr = PetscSFSetFromOptions(*sfProcess);CHKERRQ(ierr);
530     ierr = PetscSFSetGraph(*sfProcess, size, numNeighbors, localPointsNew, PETSC_OWN_POINTER, remotePointsNew, PETSC_OWN_POINTER);CHKERRQ(ierr);
531   }
532   PetscFunctionReturn(0);
533 }
534 
535 /*@
536   DMPlexDistributeOwnership - Compute owner information for shared points. This basically gets two-sided for an SF.
537 
538   Collective on DM
539 
540   Input Parameter:
541 . dm - The DM
542 
543   Output Parameters:
544 + rootSection - The number of leaves for a given root point
545 . rootrank    - The rank of each edge into the root point
546 . leafSection - The number of processes sharing a given leaf point
547 - leafrank    - The rank of each process sharing a leaf point
548 
549   Level: developer
550 
551 .seealso: DMPlexCreateOverlap()
552 @*/
553 PetscErrorCode DMPlexDistributeOwnership(DM dm, PetscSection rootSection, IS *rootrank, PetscSection leafSection, IS *leafrank)
554 {
555   MPI_Comm        comm;
556   PetscSF         sfPoint;
557   const PetscInt *rootdegree;
558   PetscInt       *myrank, *remoterank;
559   PetscInt        pStart, pEnd, p, nedges;
560   PetscMPIInt     rank;
561   PetscErrorCode  ierr;
562 
563   PetscFunctionBegin;
564   ierr = PetscObjectGetComm((PetscObject) dm, &comm);CHKERRQ(ierr);
565   ierr = MPI_Comm_rank(comm, &rank);CHKERRQ(ierr);
566   ierr = DMPlexGetChart(dm, &pStart, &pEnd);CHKERRQ(ierr);
567   ierr = DMGetPointSF(dm, &sfPoint);CHKERRQ(ierr);
568   /* Compute number of leaves for each root */
569   ierr = PetscObjectSetName((PetscObject) rootSection, "Root Section");CHKERRQ(ierr);
570   ierr = PetscSectionSetChart(rootSection, pStart, pEnd);CHKERRQ(ierr);
571   ierr = PetscSFComputeDegreeBegin(sfPoint, &rootdegree);CHKERRQ(ierr);
572   ierr = PetscSFComputeDegreeEnd(sfPoint, &rootdegree);CHKERRQ(ierr);
573   for (p = pStart; p < pEnd; ++p) {ierr = PetscSectionSetDof(rootSection, p, rootdegree[p-pStart]);CHKERRQ(ierr);}
574   ierr = PetscSectionSetUp(rootSection);CHKERRQ(ierr);
575   /* Gather rank of each leaf to root */
576   ierr = PetscSectionGetStorageSize(rootSection, &nedges);CHKERRQ(ierr);
577   ierr = PetscMalloc1(pEnd-pStart, &myrank);CHKERRQ(ierr);
578   ierr = PetscMalloc1(nedges,  &remoterank);CHKERRQ(ierr);
579   for (p = 0; p < pEnd-pStart; ++p) myrank[p] = rank;
580   ierr = PetscSFGatherBegin(sfPoint, MPIU_INT, myrank, remoterank);CHKERRQ(ierr);
581   ierr = PetscSFGatherEnd(sfPoint, MPIU_INT, myrank, remoterank);CHKERRQ(ierr);
582   ierr = PetscFree(myrank);CHKERRQ(ierr);
583   ierr = ISCreateGeneral(comm, nedges, remoterank, PETSC_OWN_POINTER, rootrank);CHKERRQ(ierr);
584   /* Distribute remote ranks to leaves */
585   ierr = PetscObjectSetName((PetscObject) leafSection, "Leaf Section");CHKERRQ(ierr);
586   ierr = DMPlexDistributeFieldIS(dm, sfPoint, rootSection, *rootrank, leafSection, leafrank);CHKERRQ(ierr);
587   PetscFunctionReturn(0);
588 }
589 
590 /*@C
591   DMPlexCreateOverlap - Compute owner information for shared points. This basically gets two-sided for an SF.
592 
593   Collective on DM
594 
595   Input Parameters:
596 + dm          - The DM
597 . levels      - Number of overlap levels
598 . rootSection - The number of leaves for a given root point
599 . rootrank    - The rank of each edge into the root point
600 . leafSection - The number of processes sharing a given leaf point
601 - leafrank    - The rank of each process sharing a leaf point
602 
603   Output Parameters:
604 + ovLabel     - DMLabel containing remote overlap contributions as point/rank pairings
605 
606   Level: developer
607 
608 .seealso: DMPlexDistributeOwnership(), DMPlexDistribute()
609 @*/
610 PetscErrorCode DMPlexCreateOverlap(DM dm, PetscInt levels, PetscSection rootSection, IS rootrank, PetscSection leafSection, IS leafrank, DMLabel *ovLabel)
611 {
612   MPI_Comm           comm;
613   DMLabel            ovAdjByRank; /* A DMLabel containing all points adjacent to shared points, separated by rank (value in label) */
614   PetscSF            sfPoint, sfProc;
615   const PetscSFNode *remote;
616   const PetscInt    *local;
617   const PetscInt    *nrank, *rrank;
618   PetscInt          *adj = NULL;
619   PetscInt           pStart, pEnd, p, sStart, sEnd, nleaves, l;
620   PetscMPIInt        rank, size;
621   PetscBool          useCone, useClosure, flg;
622   PetscErrorCode     ierr;
623 
624   PetscFunctionBegin;
625   ierr = PetscObjectGetComm((PetscObject) dm, &comm);CHKERRQ(ierr);
626   ierr = MPI_Comm_size(comm, &size);CHKERRQ(ierr);
627   ierr = MPI_Comm_rank(comm, &rank);CHKERRQ(ierr);
628   ierr = DMGetPointSF(dm, &sfPoint);CHKERRQ(ierr);
629   ierr = DMPlexGetChart(dm, &pStart, &pEnd);CHKERRQ(ierr);
630   ierr = PetscSectionGetChart(leafSection, &sStart, &sEnd);CHKERRQ(ierr);
631   ierr = PetscSFGetGraph(sfPoint, NULL, &nleaves, &local, &remote);CHKERRQ(ierr);
632   ierr = DMLabelCreate("Overlap adjacency", &ovAdjByRank);CHKERRQ(ierr);
633   /* Handle leaves: shared with the root point */
634   for (l = 0; l < nleaves; ++l) {
635     PetscInt adjSize = PETSC_DETERMINE, a;
636 
637     ierr = DMPlexGetAdjacency(dm, local[l], &adjSize, &adj);CHKERRQ(ierr);
638     for (a = 0; a < adjSize; ++a) {ierr = DMLabelSetValue(ovAdjByRank, adj[a], remote[l].rank);CHKERRQ(ierr);}
639   }
640   ierr = ISGetIndices(rootrank, &rrank);CHKERRQ(ierr);
641   ierr = ISGetIndices(leafrank, &nrank);CHKERRQ(ierr);
642   /* Handle roots */
643   for (p = pStart; p < pEnd; ++p) {
644     PetscInt adjSize = PETSC_DETERMINE, neighbors = 0, noff, n, a;
645 
646     if ((p >= sStart) && (p < sEnd)) {
647       /* Some leaves share a root with other leaves on different processes */
648       ierr = PetscSectionGetDof(leafSection, p, &neighbors);CHKERRQ(ierr);
649       if (neighbors) {
650         ierr = PetscSectionGetOffset(leafSection, p, &noff);CHKERRQ(ierr);
651         ierr = DMPlexGetAdjacency(dm, p, &adjSize, &adj);CHKERRQ(ierr);
652         for (n = 0; n < neighbors; ++n) {
653           const PetscInt remoteRank = nrank[noff+n];
654 
655           if (remoteRank == rank) continue;
656           for (a = 0; a < adjSize; ++a) {ierr = DMLabelSetValue(ovAdjByRank, adj[a], remoteRank);CHKERRQ(ierr);}
657         }
658       }
659     }
660     /* Roots are shared with leaves */
661     ierr = PetscSectionGetDof(rootSection, p, &neighbors);CHKERRQ(ierr);
662     if (!neighbors) continue;
663     ierr = PetscSectionGetOffset(rootSection, p, &noff);CHKERRQ(ierr);
664     ierr = DMPlexGetAdjacency(dm, p, &adjSize, &adj);CHKERRQ(ierr);
665     for (n = 0; n < neighbors; ++n) {
666       const PetscInt remoteRank = rrank[noff+n];
667 
668       if (remoteRank == rank) continue;
669       for (a = 0; a < adjSize; ++a) {ierr = DMLabelSetValue(ovAdjByRank, adj[a], remoteRank);CHKERRQ(ierr);}
670     }
671   }
672   ierr = PetscFree(adj);CHKERRQ(ierr);
673   ierr = ISRestoreIndices(rootrank, &rrank);CHKERRQ(ierr);
674   ierr = ISRestoreIndices(leafrank, &nrank);CHKERRQ(ierr);
675   /* Add additional overlap levels */
676   for (l = 1; l < levels; l++) {
677     /* Propagate point donations over SF to capture remote connections */
678     ierr = DMPlexPartitionLabelPropagate(dm, ovAdjByRank);CHKERRQ(ierr);
679     /* Add next level of point donations to the label */
680     ierr = DMPlexPartitionLabelAdjacency(dm, ovAdjByRank);CHKERRQ(ierr);
681   }
682   /* We require the closure in the overlap */
683   ierr = DMPlexGetAdjacencyUseCone(dm, &useCone);CHKERRQ(ierr);
684   ierr = DMPlexGetAdjacencyUseClosure(dm, &useClosure);CHKERRQ(ierr);
685   if (useCone || !useClosure) {
686     ierr = DMPlexPartitionLabelClosure(dm, ovAdjByRank);CHKERRQ(ierr);
687   }
688   ierr = PetscOptionsHasName(((PetscObject) dm)->options,((PetscObject) dm)->prefix, "-overlap_view", &flg);CHKERRQ(ierr);
689   if (flg) {
690     ierr = DMLabelView(ovAdjByRank, PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
691   }
692   /* Make global process SF and invert sender to receiver label */
693   {
694     /* Build a global process SF */
695     PetscSFNode *remoteProc;
696     ierr = PetscMalloc1(size, &remoteProc);CHKERRQ(ierr);
697     for (p = 0; p < size; ++p) {
698       remoteProc[p].rank  = p;
699       remoteProc[p].index = rank;
700     }
701     ierr = PetscSFCreate(comm, &sfProc);CHKERRQ(ierr);
702     ierr = PetscObjectSetName((PetscObject) sfProc, "Process SF");CHKERRQ(ierr);
703     ierr = PetscSFSetGraph(sfProc, size, size, NULL, PETSC_OWN_POINTER, remoteProc, PETSC_OWN_POINTER);CHKERRQ(ierr);
704   }
705   ierr = DMLabelCreate("Overlap label", ovLabel);CHKERRQ(ierr);
706   ierr = DMPlexPartitionLabelInvert(dm, ovAdjByRank, sfProc, *ovLabel);CHKERRQ(ierr);
707   /* Add owned points, except for shared local points */
708   for (p = pStart; p < pEnd; ++p) {ierr = DMLabelSetValue(*ovLabel, p, rank);CHKERRQ(ierr);}
709   for (l = 0; l < nleaves; ++l) {
710     ierr = DMLabelClearValue(*ovLabel, local[l], rank);CHKERRQ(ierr);
711     ierr = DMLabelSetValue(*ovLabel, remote[l].index, remote[l].rank);CHKERRQ(ierr);
712   }
713   /* Clean up */
714   ierr = DMLabelDestroy(&ovAdjByRank);CHKERRQ(ierr);
715   ierr = PetscSFDestroy(&sfProc);CHKERRQ(ierr);
716   PetscFunctionReturn(0);
717 }
718 
719 /*@C
720   DMPlexCreateOverlapMigrationSF - Create an SF describing the new mesh distribution to make the overlap described by the input SF
721 
722   Collective on DM
723 
724   Input Parameters:
725 + dm          - The DM
726 - overlapSF   - The SF mapping ghost points in overlap to owner points on other processes
727 
728   Output Parameters:
729 + migrationSF - An SF that maps original points in old locations to points in new locations
730 
731   Level: developer
732 
733 .seealso: DMPlexCreateOverlap(), DMPlexDistribute()
734 @*/
735 PetscErrorCode DMPlexCreateOverlapMigrationSF(DM dm, PetscSF overlapSF, PetscSF *migrationSF)
736 {
737   MPI_Comm           comm;
738   PetscMPIInt        rank, size;
739   PetscInt           d, dim, p, pStart, pEnd, nroots, nleaves, newLeaves, point, numSharedPoints;
740   PetscInt          *pointDepths, *remoteDepths, *ilocal;
741   PetscInt          *depthRecv, *depthShift, *depthIdx;
742   PetscSFNode       *iremote;
743   PetscSF            pointSF;
744   const PetscInt    *sharedLocal;
745   const PetscSFNode *overlapRemote, *sharedRemote;
746   PetscErrorCode     ierr;
747 
748   PetscFunctionBegin;
749   PetscValidHeaderSpecific(dm, DM_CLASSID, 1);
750   ierr = PetscObjectGetComm((PetscObject)dm, &comm);CHKERRQ(ierr);
751   ierr = MPI_Comm_rank(comm, &rank);CHKERRQ(ierr);
752   ierr = MPI_Comm_size(comm, &size);CHKERRQ(ierr);
753   ierr = DMGetDimension(dm, &dim);CHKERRQ(ierr);
754 
755   /* Before building the migration SF we need to know the new stratum offsets */
756   ierr = PetscSFGetGraph(overlapSF, &nroots, &nleaves, NULL, &overlapRemote);CHKERRQ(ierr);
757   ierr = PetscMalloc2(nroots, &pointDepths, nleaves, &remoteDepths);CHKERRQ(ierr);
758   for (d=0; d<dim+1; d++) {
759     ierr = DMPlexGetDepthStratum(dm, d, &pStart, &pEnd);CHKERRQ(ierr);
760     for (p=pStart; p<pEnd; p++) pointDepths[p] = d;
761   }
762   for (p=0; p<nleaves; p++) remoteDepths[p] = -1;
763   ierr = PetscSFBcastBegin(overlapSF, MPIU_INT, pointDepths, remoteDepths);CHKERRQ(ierr);
764   ierr = PetscSFBcastEnd(overlapSF, MPIU_INT, pointDepths, remoteDepths);CHKERRQ(ierr);
765 
766   /* Count recevied points in each stratum and compute the internal strata shift */
767   ierr = PetscMalloc3(dim+1, &depthRecv, dim+1, &depthShift, dim+1, &depthIdx);CHKERRQ(ierr);
768   for (d=0; d<dim+1; d++) depthRecv[d]=0;
769   for (p=0; p<nleaves; p++) depthRecv[remoteDepths[p]]++;
770   depthShift[dim] = 0;
771   for (d=0; d<dim; d++) depthShift[d] = depthRecv[dim];
772   for (d=1; d<dim; d++) depthShift[d] += depthRecv[0];
773   for (d=dim-2; d>0; d--) depthShift[d] += depthRecv[d+1];
774   for (d=0; d<dim+1; d++) {
775     ierr = DMPlexGetDepthStratum(dm, d, &pStart, &pEnd);CHKERRQ(ierr);
776     depthIdx[d] = pStart + depthShift[d];
777   }
778 
779   /* Form the overlap SF build an SF that describes the full overlap migration SF */
780   ierr = DMPlexGetChart(dm, &pStart, &pEnd);CHKERRQ(ierr);
781   newLeaves = pEnd - pStart + nleaves;
782   ierr = PetscMalloc1(newLeaves, &ilocal);CHKERRQ(ierr);
783   ierr = PetscMalloc1(newLeaves, &iremote);CHKERRQ(ierr);
784   /* First map local points to themselves */
785   for (d=0; d<dim+1; d++) {
786     ierr = DMPlexGetDepthStratum(dm, d, &pStart, &pEnd);CHKERRQ(ierr);
787     for (p=pStart; p<pEnd; p++) {
788       point = p + depthShift[d];
789       ilocal[point] = point;
790       iremote[point].index = p;
791       iremote[point].rank = rank;
792       depthIdx[d]++;
793     }
794   }
795 
796   /* Add in the remote roots for currently shared points */
797   ierr = DMGetPointSF(dm, &pointSF);CHKERRQ(ierr);
798   ierr = PetscSFGetGraph(pointSF, NULL, &numSharedPoints, &sharedLocal, &sharedRemote);CHKERRQ(ierr);
799   for (d=0; d<dim+1; d++) {
800     ierr = DMPlexGetDepthStratum(dm, d, &pStart, &pEnd);CHKERRQ(ierr);
801     for (p=0; p<numSharedPoints; p++) {
802       if (pStart <= sharedLocal[p] && sharedLocal[p] < pEnd) {
803         point = sharedLocal[p] + depthShift[d];
804         iremote[point].index = sharedRemote[p].index;
805         iremote[point].rank = sharedRemote[p].rank;
806       }
807     }
808   }
809 
810   /* Now add the incoming overlap points */
811   for (p=0; p<nleaves; p++) {
812     point = depthIdx[remoteDepths[p]];
813     ilocal[point] = point;
814     iremote[point].index = overlapRemote[p].index;
815     iremote[point].rank = overlapRemote[p].rank;
816     depthIdx[remoteDepths[p]]++;
817   }
818   ierr = PetscFree2(pointDepths,remoteDepths);CHKERRQ(ierr);
819 
820   ierr = PetscSFCreate(comm, migrationSF);CHKERRQ(ierr);
821   ierr = PetscObjectSetName((PetscObject) *migrationSF, "Overlap Migration SF");CHKERRQ(ierr);
822   ierr = PetscSFSetFromOptions(*migrationSF);CHKERRQ(ierr);
823   ierr = DMPlexGetChart(dm, &pStart, &pEnd);CHKERRQ(ierr);
824   ierr = PetscSFSetGraph(*migrationSF, pEnd-pStart, newLeaves, ilocal, PETSC_OWN_POINTER, iremote, PETSC_OWN_POINTER);CHKERRQ(ierr);
825 
826   ierr = PetscFree3(depthRecv, depthShift, depthIdx);CHKERRQ(ierr);
827   PetscFunctionReturn(0);
828 }
829 
830 /*@
831   DMPlexStratifyMigrationSF - Rearrange the leaves of a migration sf for stratification.
832 
833   Input Parameter:
834 + dm          - The DM
835 - sf          - A star forest with non-ordered leaves, usually defining a DM point migration
836 
837   Output Parameter:
838 . migrationSF - A star forest with added leaf indirection that ensures the resulting DM is stratified
839 
840   Level: developer
841 
842 .seealso: DMPlexPartitionLabelCreateSF(), DMPlexDistribute(), DMPlexDistributeOverlap()
843 @*/
844 PetscErrorCode DMPlexStratifyMigrationSF(DM dm, PetscSF sf, PetscSF *migrationSF)
845 {
846   MPI_Comm           comm;
847   PetscMPIInt        rank, size;
848   PetscInt           d, ldepth, depth, p, pStart, pEnd, nroots, nleaves;
849   PetscInt          *pointDepths, *remoteDepths, *ilocal;
850   PetscInt          *depthRecv, *depthShift, *depthIdx;
851   PetscInt           hybEnd[4];
852   const PetscSFNode *iremote;
853   PetscErrorCode     ierr;
854 
855   PetscFunctionBegin;
856   PetscValidHeaderSpecific(dm, DM_CLASSID, 1);
857   ierr = PetscObjectGetComm((PetscObject) dm, &comm);CHKERRQ(ierr);
858   ierr = MPI_Comm_rank(comm, &rank);CHKERRQ(ierr);
859   ierr = MPI_Comm_size(comm, &size);CHKERRQ(ierr);
860   ierr = DMPlexGetDepth(dm, &ldepth);CHKERRQ(ierr);
861   ierr = MPIU_Allreduce(&ldepth, &depth, 1, MPIU_INT, MPI_MAX, comm);CHKERRQ(ierr);
862   if ((ldepth >= 0) && (depth != ldepth)) SETERRQ2(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Inconsistent Plex depth %d != %d", ldepth, depth);
863 
864   /* Before building the migration SF we need to know the new stratum offsets */
865   ierr = PetscSFGetGraph(sf, &nroots, &nleaves, NULL, &iremote);CHKERRQ(ierr);
866   ierr = PetscMalloc2(nroots, &pointDepths, nleaves, &remoteDepths);CHKERRQ(ierr);
867   ierr = DMPlexGetHybridBounds(dm,&hybEnd[depth],&hybEnd[depth-1],&hybEnd[1],&hybEnd[0]);CHKERRQ(ierr);
868   for (d = 0; d < depth+1; ++d) {
869     ierr = DMPlexGetDepthStratum(dm, d, &pStart, &pEnd);CHKERRQ(ierr);
870     for (p = pStart; p < pEnd; ++p) {
871       if (hybEnd[d] >= 0 && p >= hybEnd[d]) { /* put in a separate value for hybrid points */
872         pointDepths[p] = 2 * d;
873       } else {
874         pointDepths[p] = 2 * d + 1;
875       }
876     }
877   }
878   for (p = 0; p < nleaves; ++p) remoteDepths[p] = -1;
879   ierr = PetscSFBcastBegin(sf, MPIU_INT, pointDepths, remoteDepths);CHKERRQ(ierr);
880   ierr = PetscSFBcastEnd(sf, MPIU_INT, pointDepths, remoteDepths);CHKERRQ(ierr);
881   /* Count recevied points in each stratum and compute the internal strata shift */
882   ierr = PetscMalloc3(2*(depth+1), &depthRecv, 2*(depth+1), &depthShift, 2*(depth+1), &depthIdx);CHKERRQ(ierr);
883   for (d = 0; d < 2*(depth+1); ++d) depthRecv[d] = 0;
884   for (p = 0; p < nleaves; ++p) depthRecv[remoteDepths[p]]++;
885   depthShift[2*depth+1] = 0;
886   for (d = 0; d < 2*depth+1; ++d) depthShift[d] = depthRecv[2 * depth + 1];
887   for (d = 0; d < 2*depth; ++d) depthShift[d] += depthRecv[2 * depth];
888   depthShift[0] += depthRecv[1];
889   for (d = 2; d < 2*depth; ++d) depthShift[d] += depthRecv[1];
890   for (d = 2; d < 2*depth; ++d) depthShift[d] += depthRecv[0];
891   for (d = 2 * depth-1; d > 2; --d) {
892     PetscInt e;
893 
894     for (e = d -1; e > 1; --e) depthShift[e] += depthRecv[d];
895   }
896   for (d = 0; d < 2*(depth+1); ++d) {depthIdx[d] = 0;}
897   /* Derive a new local permutation based on stratified indices */
898   ierr = PetscMalloc1(nleaves, &ilocal);CHKERRQ(ierr);
899   for (p = 0; p < nleaves; ++p) {
900     const PetscInt dep = remoteDepths[p];
901 
902     ilocal[p] = depthShift[dep] + depthIdx[dep];
903     depthIdx[dep]++;
904   }
905   ierr = PetscSFCreate(comm, migrationSF);CHKERRQ(ierr);
906   ierr = PetscObjectSetName((PetscObject) *migrationSF, "Migration SF");CHKERRQ(ierr);
907   ierr = PetscSFSetGraph(*migrationSF, nroots, nleaves, ilocal, PETSC_OWN_POINTER, iremote, PETSC_COPY_VALUES);CHKERRQ(ierr);
908   ierr = PetscFree2(pointDepths,remoteDepths);CHKERRQ(ierr);
909   ierr = PetscFree3(depthRecv, depthShift, depthIdx);CHKERRQ(ierr);
910   PetscFunctionReturn(0);
911 }
912 
913 /*@
914   DMPlexDistributeField - Distribute field data to match a given PetscSF, usually the SF from mesh distribution
915 
916   Collective on DM
917 
918   Input Parameters:
919 + dm - The DMPlex object
920 . pointSF - The PetscSF describing the communication pattern
921 . originalSection - The PetscSection for existing data layout
922 - originalVec - The existing data
923 
924   Output Parameters:
925 + newSection - The PetscSF describing the new data layout
926 - newVec - The new data
927 
928   Level: developer
929 
930 .seealso: DMPlexDistribute(), DMPlexDistributeFieldIS(), DMPlexDistributeData()
931 @*/
932 PetscErrorCode DMPlexDistributeField(DM dm, PetscSF pointSF, PetscSection originalSection, Vec originalVec, PetscSection newSection, Vec newVec)
933 {
934   PetscSF        fieldSF;
935   PetscInt      *remoteOffsets, fieldSize;
936   PetscScalar   *originalValues, *newValues;
937   PetscErrorCode ierr;
938 
939   PetscFunctionBegin;
940   ierr = PetscLogEventBegin(DMPLEX_DistributeField,dm,0,0,0);CHKERRQ(ierr);
941   ierr = PetscSFDistributeSection(pointSF, originalSection, &remoteOffsets, newSection);CHKERRQ(ierr);
942 
943   ierr = PetscSectionGetStorageSize(newSection, &fieldSize);CHKERRQ(ierr);
944   ierr = VecSetSizes(newVec, fieldSize, PETSC_DETERMINE);CHKERRQ(ierr);
945   ierr = VecSetType(newVec,dm->vectype);CHKERRQ(ierr);
946 
947   ierr = VecGetArray(originalVec, &originalValues);CHKERRQ(ierr);
948   ierr = VecGetArray(newVec, &newValues);CHKERRQ(ierr);
949   ierr = PetscSFCreateSectionSF(pointSF, originalSection, remoteOffsets, newSection, &fieldSF);CHKERRQ(ierr);
950   ierr = PetscFree(remoteOffsets);CHKERRQ(ierr);
951   ierr = PetscSFBcastBegin(fieldSF, MPIU_SCALAR, originalValues, newValues);CHKERRQ(ierr);
952   ierr = PetscSFBcastEnd(fieldSF, MPIU_SCALAR, originalValues, newValues);CHKERRQ(ierr);
953   ierr = PetscSFDestroy(&fieldSF);CHKERRQ(ierr);
954   ierr = VecRestoreArray(newVec, &newValues);CHKERRQ(ierr);
955   ierr = VecRestoreArray(originalVec, &originalValues);CHKERRQ(ierr);
956   ierr = PetscLogEventEnd(DMPLEX_DistributeField,dm,0,0,0);CHKERRQ(ierr);
957   PetscFunctionReturn(0);
958 }
959 
960 /*@
961   DMPlexDistributeFieldIS - Distribute field data to match a given PetscSF, usually the SF from mesh distribution
962 
963   Collective on DM
964 
965   Input Parameters:
966 + dm - The DMPlex object
967 . pointSF - The PetscSF describing the communication pattern
968 . originalSection - The PetscSection for existing data layout
969 - originalIS - The existing data
970 
971   Output Parameters:
972 + newSection - The PetscSF describing the new data layout
973 - newIS - The new data
974 
975   Level: developer
976 
977 .seealso: DMPlexDistribute(), DMPlexDistributeField(), DMPlexDistributeData()
978 @*/
979 PetscErrorCode DMPlexDistributeFieldIS(DM dm, PetscSF pointSF, PetscSection originalSection, IS originalIS, PetscSection newSection, IS *newIS)
980 {
981   PetscSF         fieldSF;
982   PetscInt       *newValues, *remoteOffsets, fieldSize;
983   const PetscInt *originalValues;
984   PetscErrorCode  ierr;
985 
986   PetscFunctionBegin;
987   ierr = PetscLogEventBegin(DMPLEX_DistributeField,dm,0,0,0);CHKERRQ(ierr);
988   ierr = PetscSFDistributeSection(pointSF, originalSection, &remoteOffsets, newSection);CHKERRQ(ierr);
989 
990   ierr = PetscSectionGetStorageSize(newSection, &fieldSize);CHKERRQ(ierr);
991   ierr = PetscMalloc1(fieldSize, &newValues);CHKERRQ(ierr);
992 
993   ierr = ISGetIndices(originalIS, &originalValues);CHKERRQ(ierr);
994   ierr = PetscSFCreateSectionSF(pointSF, originalSection, remoteOffsets, newSection, &fieldSF);CHKERRQ(ierr);
995   ierr = PetscFree(remoteOffsets);CHKERRQ(ierr);
996   ierr = PetscSFBcastBegin(fieldSF, MPIU_INT, (PetscInt *) originalValues, newValues);CHKERRQ(ierr);
997   ierr = PetscSFBcastEnd(fieldSF, MPIU_INT, (PetscInt *) originalValues, newValues);CHKERRQ(ierr);
998   ierr = PetscSFDestroy(&fieldSF);CHKERRQ(ierr);
999   ierr = ISRestoreIndices(originalIS, &originalValues);CHKERRQ(ierr);
1000   ierr = ISCreateGeneral(PetscObjectComm((PetscObject) pointSF), fieldSize, newValues, PETSC_OWN_POINTER, newIS);CHKERRQ(ierr);
1001   ierr = PetscLogEventEnd(DMPLEX_DistributeField,dm,0,0,0);CHKERRQ(ierr);
1002   PetscFunctionReturn(0);
1003 }
1004 
1005 /*@
1006   DMPlexDistributeData - Distribute field data to match a given PetscSF, usually the SF from mesh distribution
1007 
1008   Collective on DM
1009 
1010   Input Parameters:
1011 + dm - The DMPlex object
1012 . pointSF - The PetscSF describing the communication pattern
1013 . originalSection - The PetscSection for existing data layout
1014 . datatype - The type of data
1015 - originalData - The existing data
1016 
1017   Output Parameters:
1018 + newSection - The PetscSection describing the new data layout
1019 - newData - The new data
1020 
1021   Level: developer
1022 
1023 .seealso: DMPlexDistribute(), DMPlexDistributeField()
1024 @*/
1025 PetscErrorCode DMPlexDistributeData(DM dm, PetscSF pointSF, PetscSection originalSection, MPI_Datatype datatype, void *originalData, PetscSection newSection, void **newData)
1026 {
1027   PetscSF        fieldSF;
1028   PetscInt      *remoteOffsets, fieldSize;
1029   PetscMPIInt    dataSize;
1030   PetscErrorCode ierr;
1031 
1032   PetscFunctionBegin;
1033   ierr = PetscLogEventBegin(DMPLEX_DistributeData,dm,0,0,0);CHKERRQ(ierr);
1034   ierr = PetscSFDistributeSection(pointSF, originalSection, &remoteOffsets, newSection);CHKERRQ(ierr);
1035 
1036   ierr = PetscSectionGetStorageSize(newSection, &fieldSize);CHKERRQ(ierr);
1037   ierr = MPI_Type_size(datatype, &dataSize);CHKERRQ(ierr);
1038   ierr = PetscMalloc(fieldSize * dataSize, newData);CHKERRQ(ierr);
1039 
1040   ierr = PetscSFCreateSectionSF(pointSF, originalSection, remoteOffsets, newSection, &fieldSF);CHKERRQ(ierr);
1041   ierr = PetscFree(remoteOffsets);CHKERRQ(ierr);
1042   ierr = PetscSFBcastBegin(fieldSF, datatype, originalData, *newData);CHKERRQ(ierr);
1043   ierr = PetscSFBcastEnd(fieldSF, datatype, originalData, *newData);CHKERRQ(ierr);
1044   ierr = PetscSFDestroy(&fieldSF);CHKERRQ(ierr);
1045   ierr = PetscLogEventEnd(DMPLEX_DistributeData,dm,0,0,0);CHKERRQ(ierr);
1046   PetscFunctionReturn(0);
1047 }
1048 
1049 static PetscErrorCode DMPlexDistributeCones(DM dm, PetscSF migrationSF, ISLocalToGlobalMapping original, ISLocalToGlobalMapping renumbering, DM dmParallel)
1050 {
1051   DM_Plex               *pmesh = (DM_Plex*) (dmParallel)->data;
1052   MPI_Comm               comm;
1053   PetscSF                coneSF;
1054   PetscSection           originalConeSection, newConeSection;
1055   PetscInt              *remoteOffsets, *cones, *globCones, *newCones, newConesSize;
1056   PetscBool              flg;
1057   PetscErrorCode         ierr;
1058 
1059   PetscFunctionBegin;
1060   PetscValidHeaderSpecific(dm, DM_CLASSID, 1);
1061   PetscValidPointer(dmParallel,4);
1062   ierr = PetscLogEventBegin(DMPLEX_DistributeCones,dm,0,0,0);CHKERRQ(ierr);
1063 
1064   /* Distribute cone section */
1065   ierr = PetscObjectGetComm((PetscObject)dm, &comm);CHKERRQ(ierr);
1066   ierr = DMPlexGetConeSection(dm, &originalConeSection);CHKERRQ(ierr);
1067   ierr = DMPlexGetConeSection(dmParallel, &newConeSection);CHKERRQ(ierr);
1068   ierr = PetscSFDistributeSection(migrationSF, originalConeSection, &remoteOffsets, newConeSection);CHKERRQ(ierr);
1069   ierr = DMSetUp(dmParallel);CHKERRQ(ierr);
1070   {
1071     PetscInt pStart, pEnd, p;
1072 
1073     ierr = PetscSectionGetChart(newConeSection, &pStart, &pEnd);CHKERRQ(ierr);
1074     for (p = pStart; p < pEnd; ++p) {
1075       PetscInt coneSize;
1076       ierr               = PetscSectionGetDof(newConeSection, p, &coneSize);CHKERRQ(ierr);
1077       pmesh->maxConeSize = PetscMax(pmesh->maxConeSize, coneSize);
1078     }
1079   }
1080   /* Communicate and renumber cones */
1081   ierr = PetscSFCreateSectionSF(migrationSF, originalConeSection, remoteOffsets, newConeSection, &coneSF);CHKERRQ(ierr);
1082   ierr = PetscFree(remoteOffsets);CHKERRQ(ierr);
1083   ierr = DMPlexGetCones(dm, &cones);CHKERRQ(ierr);
1084   if (original) {
1085     PetscInt numCones;
1086 
1087     ierr = PetscSectionGetStorageSize(originalConeSection,&numCones);CHKERRQ(ierr); ierr = PetscMalloc1(numCones,&globCones);CHKERRQ(ierr);
1088     ierr = ISLocalToGlobalMappingApplyBlock(original, numCones, cones, globCones);CHKERRQ(ierr);
1089   }
1090   else {
1091     globCones = cones;
1092   }
1093   ierr = DMPlexGetCones(dmParallel, &newCones);CHKERRQ(ierr);
1094   ierr = PetscSFBcastBegin(coneSF, MPIU_INT, globCones, newCones);CHKERRQ(ierr);
1095   ierr = PetscSFBcastEnd(coneSF, MPIU_INT, globCones, newCones);CHKERRQ(ierr);
1096   if (original) {
1097     ierr = PetscFree(globCones);CHKERRQ(ierr);
1098   }
1099   ierr = PetscSectionGetStorageSize(newConeSection, &newConesSize);CHKERRQ(ierr);
1100   ierr = ISGlobalToLocalMappingApplyBlock(renumbering, IS_GTOLM_MASK, newConesSize, newCones, NULL, newCones);CHKERRQ(ierr);
1101 #if PETSC_USE_DEBUG
1102   {
1103     PetscInt  p;
1104     PetscBool valid = PETSC_TRUE;
1105     for (p = 0; p < newConesSize; ++p) {
1106       if (newCones[p] < 0) {valid = PETSC_FALSE; ierr = PetscPrintf(PETSC_COMM_SELF, "Point %d not in overlap SF\n", p);CHKERRQ(ierr);}
1107     }
1108     if (!valid) SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Invalid global to local map");
1109   }
1110 #endif
1111   ierr = PetscOptionsHasName(((PetscObject) dm)->options,((PetscObject) dm)->prefix, "-cones_view", &flg);CHKERRQ(ierr);
1112   if (flg) {
1113     ierr = PetscPrintf(comm, "Serial Cone Section:\n");CHKERRQ(ierr);
1114     ierr = PetscSectionView(originalConeSection, PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
1115     ierr = PetscPrintf(comm, "Parallel Cone Section:\n");CHKERRQ(ierr);
1116     ierr = PetscSectionView(newConeSection, PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
1117     ierr = PetscSFView(coneSF, NULL);CHKERRQ(ierr);
1118   }
1119   ierr = DMPlexGetConeOrientations(dm, &cones);CHKERRQ(ierr);
1120   ierr = DMPlexGetConeOrientations(dmParallel, &newCones);CHKERRQ(ierr);
1121   ierr = PetscSFBcastBegin(coneSF, MPIU_INT, cones, newCones);CHKERRQ(ierr);
1122   ierr = PetscSFBcastEnd(coneSF, MPIU_INT, cones, newCones);CHKERRQ(ierr);
1123   ierr = PetscSFDestroy(&coneSF);CHKERRQ(ierr);
1124   ierr = PetscLogEventEnd(DMPLEX_DistributeCones,dm,0,0,0);CHKERRQ(ierr);
1125   /* Create supports and stratify DMPlex */
1126   {
1127     PetscInt pStart, pEnd;
1128 
1129     ierr = PetscSectionGetChart(pmesh->coneSection, &pStart, &pEnd);CHKERRQ(ierr);
1130     ierr = PetscSectionSetChart(pmesh->supportSection, pStart, pEnd);CHKERRQ(ierr);
1131   }
1132   ierr = DMPlexSymmetrize(dmParallel);CHKERRQ(ierr);
1133   ierr = DMPlexStratify(dmParallel);CHKERRQ(ierr);
1134   {
1135     PetscBool useCone, useClosure, useAnchors;
1136 
1137     ierr = DMPlexGetAdjacencyUseCone(dm, &useCone);CHKERRQ(ierr);
1138     ierr = DMPlexGetAdjacencyUseClosure(dm, &useClosure);CHKERRQ(ierr);
1139     ierr = DMPlexGetAdjacencyUseAnchors(dm, &useAnchors);CHKERRQ(ierr);
1140     ierr = DMPlexSetAdjacencyUseCone(dmParallel, useCone);CHKERRQ(ierr);
1141     ierr = DMPlexSetAdjacencyUseClosure(dmParallel, useClosure);CHKERRQ(ierr);
1142     ierr = DMPlexSetAdjacencyUseAnchors(dmParallel, useAnchors);CHKERRQ(ierr);
1143   }
1144   PetscFunctionReturn(0);
1145 }
1146 
1147 static PetscErrorCode DMPlexDistributeCoordinates(DM dm, PetscSF migrationSF, DM dmParallel)
1148 {
1149   MPI_Comm         comm;
1150   PetscSection     originalCoordSection, newCoordSection;
1151   Vec              originalCoordinates, newCoordinates;
1152   PetscInt         bs;
1153   PetscBool        isper;
1154   const char      *name;
1155   const PetscReal *maxCell, *L;
1156   const DMBoundaryType *bd;
1157   PetscErrorCode   ierr;
1158 
1159   PetscFunctionBegin;
1160   PetscValidHeaderSpecific(dm, DM_CLASSID, 1);
1161   PetscValidPointer(dmParallel, 3);
1162 
1163   ierr = PetscObjectGetComm((PetscObject)dm, &comm);CHKERRQ(ierr);
1164   ierr = DMGetCoordinateSection(dm, &originalCoordSection);CHKERRQ(ierr);
1165   ierr = DMGetCoordinateSection(dmParallel, &newCoordSection);CHKERRQ(ierr);
1166   ierr = DMGetCoordinatesLocal(dm, &originalCoordinates);CHKERRQ(ierr);
1167   if (originalCoordinates) {
1168     ierr = VecCreate(PETSC_COMM_SELF, &newCoordinates);CHKERRQ(ierr);
1169     ierr = PetscObjectGetName((PetscObject) originalCoordinates, &name);CHKERRQ(ierr);
1170     ierr = PetscObjectSetName((PetscObject) newCoordinates, name);CHKERRQ(ierr);
1171 
1172     ierr = DMPlexDistributeField(dm, migrationSF, originalCoordSection, originalCoordinates, newCoordSection, newCoordinates);CHKERRQ(ierr);
1173     ierr = DMSetCoordinatesLocal(dmParallel, newCoordinates);CHKERRQ(ierr);
1174     ierr = VecGetBlockSize(originalCoordinates, &bs);CHKERRQ(ierr);
1175     ierr = VecSetBlockSize(newCoordinates, bs);CHKERRQ(ierr);
1176     ierr = VecDestroy(&newCoordinates);CHKERRQ(ierr);
1177   }
1178   ierr = DMGetPeriodicity(dm, &isper, &maxCell, &L, &bd);CHKERRQ(ierr);
1179   ierr = DMSetPeriodicity(dmParallel, isper, maxCell, L, bd);CHKERRQ(ierr);
1180   PetscFunctionReturn(0);
1181 }
1182 
1183 /* Here we are assuming that process 0 always has everything */
1184 static PetscErrorCode DMPlexDistributeLabels(DM dm, PetscSF migrationSF, DM dmParallel)
1185 {
1186   DM_Plex         *mesh = (DM_Plex*) dm->data;
1187   MPI_Comm         comm;
1188   DMLabel          depthLabel;
1189   PetscMPIInt      rank;
1190   PetscInt         depth, d, numLabels, numLocalLabels, l;
1191   PetscBool        hasLabels = PETSC_FALSE, lsendDepth, sendDepth;
1192   PetscObjectState depthState = -1;
1193   PetscErrorCode   ierr;
1194 
1195   PetscFunctionBegin;
1196   PetscValidHeaderSpecific(dm, DM_CLASSID, 1);
1197   PetscValidHeaderSpecific(dm, DM_CLASSID, 3);
1198   ierr = PetscLogEventBegin(DMPLEX_DistributeLabels,dm,0,0,0);CHKERRQ(ierr);
1199   ierr = PetscObjectGetComm((PetscObject)dm, &comm);CHKERRQ(ierr);
1200   ierr = MPI_Comm_rank(comm, &rank);CHKERRQ(ierr);
1201 
1202   /* If the user has changed the depth label, communicate it instead */
1203   ierr = DMPlexGetDepth(dm, &depth);CHKERRQ(ierr);
1204   ierr = DMPlexGetDepthLabel(dm, &depthLabel);CHKERRQ(ierr);
1205   if (depthLabel) {ierr = DMLabelGetState(depthLabel, &depthState);CHKERRQ(ierr);}
1206   lsendDepth = mesh->depthState != depthState ? PETSC_TRUE : PETSC_FALSE;
1207   ierr = MPIU_Allreduce(&lsendDepth, &sendDepth, 1, MPIU_BOOL, MPI_LOR, comm);CHKERRQ(ierr);
1208   if (sendDepth) {
1209     ierr = DMRemoveLabel(dmParallel, "depth", &depthLabel);CHKERRQ(ierr);
1210     ierr = DMLabelDestroy(&depthLabel);CHKERRQ(ierr);
1211   }
1212   /* Everyone must have either the same number of labels, or none */
1213   ierr = DMGetNumLabels(dm, &numLocalLabels);CHKERRQ(ierr);
1214   numLabels = numLocalLabels;
1215   ierr = MPI_Bcast(&numLabels, 1, MPIU_INT, 0, comm);CHKERRQ(ierr);
1216   if (numLabels == numLocalLabels) hasLabels = PETSC_TRUE;
1217   for (l = numLabels-1; l >= 0; --l) {
1218     DMLabel     label = NULL, labelNew = NULL;
1219     PetscBool   isDepth, lisOutput = PETSC_TRUE, isOutput;
1220 
1221     if (hasLabels) {ierr = DMGetLabelByNum(dm, l, &label);CHKERRQ(ierr);}
1222     /* Skip "depth" because it is recreated */
1223     if (hasLabels) {ierr = PetscStrcmp(label->name, "depth", &isDepth);CHKERRQ(ierr);}
1224     ierr = MPI_Bcast(&isDepth, 1, MPIU_BOOL, 0, comm);CHKERRQ(ierr);
1225     if (isDepth && !sendDepth) continue;
1226     ierr = DMLabelDistribute(label, migrationSF, &labelNew);CHKERRQ(ierr);
1227     if (isDepth) {
1228       /* Put in any missing strata which can occur if users are managing the depth label themselves */
1229       PetscInt gdepth;
1230 
1231       ierr = MPIU_Allreduce(&depth, &gdepth, 1, MPIU_INT, MPI_MAX, comm);CHKERRQ(ierr);
1232       if ((depth >= 0) && (gdepth != depth)) SETERRQ2(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Inconsistent Plex depth %d != %d", depth, gdepth);
1233       for (d = 0; d <= gdepth; ++d) {
1234         PetscBool has;
1235 
1236         ierr = DMLabelHasStratum(labelNew, d, &has);CHKERRQ(ierr);
1237         if (!has) {ierr = DMLabelAddStratum(labelNew, d);CHKERRQ(ierr);}
1238       }
1239     }
1240     ierr = DMAddLabel(dmParallel, labelNew);CHKERRQ(ierr);
1241     /* Put the output flag in the new label */
1242     if (hasLabels) {ierr = DMGetLabelOutput(dm, label->name, &lisOutput);CHKERRQ(ierr);}
1243     ierr = MPIU_Allreduce(&lisOutput, &isOutput, 1, MPIU_BOOL, MPI_LAND, comm);CHKERRQ(ierr);
1244     ierr = DMSetLabelOutput(dmParallel, labelNew->name, isOutput);CHKERRQ(ierr);
1245   }
1246   ierr = PetscLogEventEnd(DMPLEX_DistributeLabels,dm,0,0,0);CHKERRQ(ierr);
1247   PetscFunctionReturn(0);
1248 }
1249 
1250 static PetscErrorCode DMPlexDistributeSetupHybrid(DM dm, PetscSF migrationSF, ISLocalToGlobalMapping renumbering, DM dmParallel)
1251 {
1252   DM_Plex        *mesh  = (DM_Plex*) dm->data;
1253   DM_Plex        *pmesh = (DM_Plex*) (dmParallel)->data;
1254   PetscBool      *isHybrid, *isHybridParallel;
1255   PetscInt        dim, depth, d;
1256   PetscInt        pStart, pEnd, pStartP, pEndP;
1257   PetscErrorCode  ierr;
1258 
1259   PetscFunctionBegin;
1260   PetscValidHeaderSpecific(dm, DM_CLASSID, 1);
1261   PetscValidPointer(dmParallel, 4);
1262 
1263   ierr = DMGetDimension(dm, &dim);CHKERRQ(ierr);
1264   ierr = DMPlexGetDepth(dm, &depth);CHKERRQ(ierr);
1265   ierr = DMPlexGetChart(dm,&pStart,&pEnd);CHKERRQ(ierr);
1266   ierr = DMPlexGetChart(dmParallel,&pStartP,&pEndP);CHKERRQ(ierr);
1267   ierr = PetscCalloc2(pEnd-pStart,&isHybrid,pEndP-pStartP,&isHybridParallel);CHKERRQ(ierr);
1268   for (d = 0; d <= depth; d++) {
1269     PetscInt hybridMax = (depth == 1 && d == 1) ? mesh->hybridPointMax[dim] : mesh->hybridPointMax[d];
1270 
1271     if (hybridMax >= 0) {
1272       PetscInt sStart, sEnd, p;
1273 
1274       ierr = DMPlexGetDepthStratum(dm,d,&sStart,&sEnd);CHKERRQ(ierr);
1275       for (p = hybridMax; p < sEnd; p++) isHybrid[p-pStart] = PETSC_TRUE;
1276     }
1277   }
1278   ierr = PetscSFBcastBegin(migrationSF,MPIU_BOOL,isHybrid,isHybridParallel);CHKERRQ(ierr);
1279   ierr = PetscSFBcastEnd(migrationSF,MPIU_BOOL,isHybrid,isHybridParallel);CHKERRQ(ierr);
1280   for (d = 0; d <= dim; d++) pmesh->hybridPointMax[d] = -1;
1281   for (d = 0; d <= depth; d++) {
1282     PetscInt sStart, sEnd, p, dd;
1283 
1284     ierr = DMPlexGetDepthStratum(dmParallel,d,&sStart,&sEnd);CHKERRQ(ierr);
1285     dd = (depth == 1 && d == 1) ? dim : d;
1286     for (p = sStart; p < sEnd; p++) {
1287       if (isHybridParallel[p-pStartP]) {
1288         pmesh->hybridPointMax[dd] = p;
1289         break;
1290       }
1291     }
1292   }
1293   ierr = PetscFree2(isHybrid,isHybridParallel);CHKERRQ(ierr);
1294   PetscFunctionReturn(0);
1295 }
1296 
1297 static PetscErrorCode DMPlexDistributeSetupTree(DM dm, PetscSF migrationSF, ISLocalToGlobalMapping original, ISLocalToGlobalMapping renumbering, DM dmParallel)
1298 {
1299   DM_Plex        *mesh  = (DM_Plex*) dm->data;
1300   DM_Plex        *pmesh = (DM_Plex*) (dmParallel)->data;
1301   MPI_Comm        comm;
1302   DM              refTree;
1303   PetscSection    origParentSection, newParentSection;
1304   PetscInt        *origParents, *origChildIDs;
1305   PetscBool       flg;
1306   PetscErrorCode  ierr;
1307 
1308   PetscFunctionBegin;
1309   PetscValidHeaderSpecific(dm, DM_CLASSID, 1);
1310   PetscValidHeaderSpecific(dm, DM_CLASSID, 4);
1311   ierr = PetscObjectGetComm((PetscObject)dm, &comm);CHKERRQ(ierr);
1312 
1313   /* Set up tree */
1314   ierr = DMPlexGetReferenceTree(dm,&refTree);CHKERRQ(ierr);
1315   ierr = DMPlexSetReferenceTree(dmParallel,refTree);CHKERRQ(ierr);
1316   ierr = DMPlexGetTree(dm,&origParentSection,&origParents,&origChildIDs,NULL,NULL);CHKERRQ(ierr);
1317   if (origParentSection) {
1318     PetscInt        pStart, pEnd;
1319     PetscInt        *newParents, *newChildIDs, *globParents;
1320     PetscInt        *remoteOffsetsParents, newParentSize;
1321     PetscSF         parentSF;
1322 
1323     ierr = DMPlexGetChart(dmParallel, &pStart, &pEnd);CHKERRQ(ierr);
1324     ierr = PetscSectionCreate(PetscObjectComm((PetscObject)dmParallel),&newParentSection);CHKERRQ(ierr);
1325     ierr = PetscSectionSetChart(newParentSection,pStart,pEnd);CHKERRQ(ierr);
1326     ierr = PetscSFDistributeSection(migrationSF, origParentSection, &remoteOffsetsParents, newParentSection);CHKERRQ(ierr);
1327     ierr = PetscSFCreateSectionSF(migrationSF, origParentSection, remoteOffsetsParents, newParentSection, &parentSF);CHKERRQ(ierr);
1328     ierr = PetscFree(remoteOffsetsParents);CHKERRQ(ierr);
1329     ierr = PetscSectionGetStorageSize(newParentSection,&newParentSize);CHKERRQ(ierr);
1330     ierr = PetscMalloc2(newParentSize,&newParents,newParentSize,&newChildIDs);CHKERRQ(ierr);
1331     if (original) {
1332       PetscInt numParents;
1333 
1334       ierr = PetscSectionGetStorageSize(origParentSection,&numParents);CHKERRQ(ierr);
1335       ierr = PetscMalloc1(numParents,&globParents);CHKERRQ(ierr);
1336       ierr = ISLocalToGlobalMappingApplyBlock(original, numParents, origParents, globParents);CHKERRQ(ierr);
1337     }
1338     else {
1339       globParents = origParents;
1340     }
1341     ierr = PetscSFBcastBegin(parentSF, MPIU_INT, globParents, newParents);CHKERRQ(ierr);
1342     ierr = PetscSFBcastEnd(parentSF, MPIU_INT, globParents, newParents);CHKERRQ(ierr);
1343     if (original) {
1344       ierr = PetscFree(globParents);CHKERRQ(ierr);
1345     }
1346     ierr = PetscSFBcastBegin(parentSF, MPIU_INT, origChildIDs, newChildIDs);CHKERRQ(ierr);
1347     ierr = PetscSFBcastEnd(parentSF, MPIU_INT, origChildIDs, newChildIDs);CHKERRQ(ierr);
1348     ierr = ISGlobalToLocalMappingApplyBlock(renumbering,IS_GTOLM_MASK, newParentSize, newParents, NULL, newParents);CHKERRQ(ierr);
1349 #if PETSC_USE_DEBUG
1350     {
1351       PetscInt  p;
1352       PetscBool valid = PETSC_TRUE;
1353       for (p = 0; p < newParentSize; ++p) {
1354         if (newParents[p] < 0) {valid = PETSC_FALSE; ierr = PetscPrintf(PETSC_COMM_SELF, "Point %d not in overlap SF\n", p);CHKERRQ(ierr);}
1355       }
1356       if (!valid) SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Invalid global to local map");
1357     }
1358 #endif
1359     ierr = PetscOptionsHasName(((PetscObject) dm)->options,((PetscObject) dm)->prefix, "-parents_view", &flg);CHKERRQ(ierr);
1360     if (flg) {
1361       ierr = PetscPrintf(comm, "Serial Parent Section: \n");CHKERRQ(ierr);
1362       ierr = PetscSectionView(origParentSection, PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
1363       ierr = PetscPrintf(comm, "Parallel Parent Section: \n");CHKERRQ(ierr);
1364       ierr = PetscSectionView(newParentSection, PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
1365       ierr = PetscSFView(parentSF, NULL);CHKERRQ(ierr);
1366     }
1367     ierr = DMPlexSetTree(dmParallel,newParentSection,newParents,newChildIDs);CHKERRQ(ierr);
1368     ierr = PetscSectionDestroy(&newParentSection);CHKERRQ(ierr);
1369     ierr = PetscFree2(newParents,newChildIDs);CHKERRQ(ierr);
1370     ierr = PetscSFDestroy(&parentSF);CHKERRQ(ierr);
1371   }
1372   pmesh->useAnchors = mesh->useAnchors;
1373   PetscFunctionReturn(0);
1374 }
1375 
1376 PETSC_UNUSED static PetscErrorCode DMPlexDistributeSF(DM dm, PetscSF migrationSF, DM dmParallel)
1377 {
1378   PetscMPIInt            rank, size;
1379   MPI_Comm               comm;
1380   PetscErrorCode         ierr;
1381 
1382   PetscFunctionBegin;
1383   PetscValidHeaderSpecific(dm, DM_CLASSID, 1);
1384   PetscValidPointer(dmParallel,7);
1385 
1386   /* Create point SF for parallel mesh */
1387   ierr = PetscLogEventBegin(DMPLEX_DistributeSF,dm,0,0,0);CHKERRQ(ierr);
1388   ierr = PetscObjectGetComm((PetscObject)dm, &comm);CHKERRQ(ierr);
1389   ierr = MPI_Comm_rank(comm, &rank);CHKERRQ(ierr);
1390   ierr = MPI_Comm_size(comm, &size);CHKERRQ(ierr);
1391   {
1392     const PetscInt *leaves;
1393     PetscSFNode    *remotePoints, *rowners, *lowners;
1394     PetscInt        numRoots, numLeaves, numGhostPoints = 0, p, gp, *ghostPoints;
1395     PetscInt        pStart, pEnd;
1396 
1397     ierr = DMPlexGetChart(dmParallel, &pStart, &pEnd);CHKERRQ(ierr);
1398     ierr = PetscSFGetGraph(migrationSF, &numRoots, &numLeaves, &leaves, NULL);CHKERRQ(ierr);
1399     ierr = PetscMalloc2(numRoots,&rowners,numLeaves,&lowners);CHKERRQ(ierr);
1400     for (p=0; p<numRoots; p++) {
1401       rowners[p].rank  = -1;
1402       rowners[p].index = -1;
1403     }
1404     ierr = PetscSFBcastBegin(migrationSF, MPIU_2INT, rowners, lowners);CHKERRQ(ierr);
1405     ierr = PetscSFBcastEnd(migrationSF, MPIU_2INT, rowners, lowners);CHKERRQ(ierr);
1406     for (p = 0; p < numLeaves; ++p) {
1407       if (lowners[p].rank < 0 || lowners[p].rank == rank) { /* Either put in a bid or we know we own it */
1408         lowners[p].rank  = rank;
1409         lowners[p].index = leaves ? leaves[p] : p;
1410       } else if (lowners[p].rank >= 0) { /* Point already claimed so flag so that MAXLOC does not listen to us */
1411         lowners[p].rank  = -2;
1412         lowners[p].index = -2;
1413       }
1414     }
1415     for (p=0; p<numRoots; p++) { /* Root must not participate in the rediction, flag so that MAXLOC does not use */
1416       rowners[p].rank  = -3;
1417       rowners[p].index = -3;
1418     }
1419     ierr = PetscSFReduceBegin(migrationSF, MPIU_2INT, lowners, rowners, MPI_MAXLOC);CHKERRQ(ierr);
1420     ierr = PetscSFReduceEnd(migrationSF, MPIU_2INT, lowners, rowners, MPI_MAXLOC);CHKERRQ(ierr);
1421     ierr = PetscSFBcastBegin(migrationSF, MPIU_2INT, rowners, lowners);CHKERRQ(ierr);
1422     ierr = PetscSFBcastEnd(migrationSF, MPIU_2INT, rowners, lowners);CHKERRQ(ierr);
1423     for (p = 0; p < numLeaves; ++p) {
1424       if (lowners[p].rank < 0 || lowners[p].index < 0) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Cell partition corrupt: point not claimed");
1425       if (lowners[p].rank != rank) ++numGhostPoints;
1426     }
1427     ierr = PetscMalloc1(numGhostPoints, &ghostPoints);CHKERRQ(ierr);
1428     ierr = PetscMalloc1(numGhostPoints, &remotePoints);CHKERRQ(ierr);
1429     for (p = 0, gp = 0; p < numLeaves; ++p) {
1430       if (lowners[p].rank != rank) {
1431         ghostPoints[gp]        = leaves ? leaves[p] : p;
1432         remotePoints[gp].rank  = lowners[p].rank;
1433         remotePoints[gp].index = lowners[p].index;
1434         ++gp;
1435       }
1436     }
1437     ierr = PetscFree2(rowners,lowners);CHKERRQ(ierr);
1438     ierr = PetscSFSetGraph((dmParallel)->sf, pEnd - pStart, numGhostPoints, ghostPoints, PETSC_OWN_POINTER, remotePoints, PETSC_OWN_POINTER);CHKERRQ(ierr);
1439     ierr = PetscSFSetFromOptions((dmParallel)->sf);CHKERRQ(ierr);
1440   }
1441   {
1442     PetscBool useCone, useClosure, useAnchors;
1443 
1444     ierr = DMPlexGetAdjacencyUseCone(dm, &useCone);CHKERRQ(ierr);
1445     ierr = DMPlexGetAdjacencyUseClosure(dm, &useClosure);CHKERRQ(ierr);
1446     ierr = DMPlexGetAdjacencyUseAnchors(dm, &useAnchors);CHKERRQ(ierr);
1447     ierr = DMPlexSetAdjacencyUseCone(dmParallel, useCone);CHKERRQ(ierr);
1448     ierr = DMPlexSetAdjacencyUseClosure(dmParallel, useClosure);CHKERRQ(ierr);
1449     ierr = DMPlexSetAdjacencyUseAnchors(dmParallel, useAnchors);CHKERRQ(ierr);
1450   }
1451   ierr = PetscLogEventEnd(DMPLEX_DistributeSF,dm,0,0,0);CHKERRQ(ierr);
1452   PetscFunctionReturn(0);
1453 }
1454 
1455 /*@C
1456   DMPlexDerivePointSF - Build a point SF from an SF describing a point migration
1457 
1458   Input Parameter:
1459 + dm          - The source DMPlex object
1460 . migrationSF - The star forest that describes the parallel point remapping
1461 . ownership   - Flag causing a vote to determine point ownership
1462 
1463   Output Parameter:
1464 - pointSF     - The star forest describing the point overlap in the remapped DM
1465 
1466   Level: developer
1467 
1468 .seealso: DMPlexDistribute(), DMPlexDistributeOverlap()
1469 @*/
1470 PetscErrorCode DMPlexCreatePointSF(DM dm, PetscSF migrationSF, PetscBool ownership, PetscSF *pointSF)
1471 {
1472   PetscMPIInt        rank;
1473   PetscInt           p, nroots, nleaves, idx, npointLeaves;
1474   PetscInt          *pointLocal;
1475   const PetscInt    *leaves;
1476   const PetscSFNode *roots;
1477   PetscSFNode       *rootNodes, *leafNodes, *pointRemote;
1478   PetscErrorCode     ierr;
1479 
1480   PetscFunctionBegin;
1481   PetscValidHeaderSpecific(dm, DM_CLASSID, 1);
1482   ierr = MPI_Comm_rank(PetscObjectComm((PetscObject) dm), &rank);CHKERRQ(ierr);
1483 
1484   ierr = PetscSFGetGraph(migrationSF, &nroots, &nleaves, &leaves, &roots);CHKERRQ(ierr);
1485   ierr = PetscMalloc2(nroots, &rootNodes, nleaves, &leafNodes);CHKERRQ(ierr);
1486   if (ownership) {
1487     /* Point ownership vote: Process with highest rank ownes shared points */
1488     for (p = 0; p < nleaves; ++p) {
1489       /* Either put in a bid or we know we own it */
1490       leafNodes[p].rank  = rank;
1491       leafNodes[p].index = p;
1492     }
1493     for (p = 0; p < nroots; p++) {
1494       /* Root must not participate in the reduction, flag so that MAXLOC does not use */
1495       rootNodes[p].rank  = -3;
1496       rootNodes[p].index = -3;
1497     }
1498     ierr = PetscSFReduceBegin(migrationSF, MPIU_2INT, leafNodes, rootNodes, MPI_MAXLOC);CHKERRQ(ierr);
1499     ierr = PetscSFReduceEnd(migrationSF, MPIU_2INT, leafNodes, rootNodes, MPI_MAXLOC);CHKERRQ(ierr);
1500   } else {
1501     for (p = 0; p < nroots; p++) {
1502       rootNodes[p].index = -1;
1503       rootNodes[p].rank = rank;
1504     };
1505     for (p = 0; p < nleaves; p++) {
1506       /* Write new local id into old location */
1507       if (roots[p].rank == rank) {
1508         rootNodes[roots[p].index].index = leaves ? leaves[p] : p;
1509       }
1510     }
1511   }
1512   ierr = PetscSFBcastBegin(migrationSF, MPIU_2INT, rootNodes, leafNodes);CHKERRQ(ierr);
1513   ierr = PetscSFBcastEnd(migrationSF, MPIU_2INT, rootNodes, leafNodes);CHKERRQ(ierr);
1514 
1515   for (npointLeaves = 0, p = 0; p < nleaves; p++) {if (leafNodes[p].rank != rank) npointLeaves++;}
1516   ierr = PetscMalloc1(npointLeaves, &pointLocal);CHKERRQ(ierr);
1517   ierr = PetscMalloc1(npointLeaves, &pointRemote);CHKERRQ(ierr);
1518   for (idx = 0, p = 0; p < nleaves; p++) {
1519     if (leafNodes[p].rank != rank) {
1520       pointLocal[idx] = p;
1521       pointRemote[idx] = leafNodes[p];
1522       idx++;
1523     }
1524   }
1525   ierr = PetscSFCreate(PetscObjectComm((PetscObject) dm), pointSF);CHKERRQ(ierr);
1526   ierr = PetscSFSetFromOptions(*pointSF);CHKERRQ(ierr);
1527   ierr = PetscSFSetGraph(*pointSF, nleaves, npointLeaves, pointLocal, PETSC_OWN_POINTER, pointRemote, PETSC_OWN_POINTER);CHKERRQ(ierr);
1528   ierr = PetscFree2(rootNodes, leafNodes);CHKERRQ(ierr);
1529   PetscFunctionReturn(0);
1530 }
1531 
1532 /*@C
1533   DMPlexMigrate  - Migrates internal DM data over the supplied star forest
1534 
1535   Input Parameter:
1536 + dm       - The source DMPlex object
1537 . sf       - The star forest communication context describing the migration pattern
1538 
1539   Output Parameter:
1540 - targetDM - The target DMPlex object
1541 
1542   Level: intermediate
1543 
1544 .seealso: DMPlexDistribute(), DMPlexDistributeOverlap()
1545 @*/
1546 PetscErrorCode DMPlexMigrate(DM dm, PetscSF sf, DM targetDM)
1547 {
1548   MPI_Comm               comm;
1549   PetscInt               dim, nroots;
1550   PetscSF                sfPoint;
1551   ISLocalToGlobalMapping ltogMigration;
1552   ISLocalToGlobalMapping ltogOriginal = NULL;
1553   PetscBool              flg;
1554   PetscErrorCode         ierr;
1555 
1556   PetscFunctionBegin;
1557   PetscValidHeaderSpecific(dm, DM_CLASSID, 1);
1558   ierr = PetscLogEventBegin(DMPLEX_Migrate, dm, 0, 0, 0);CHKERRQ(ierr);
1559   ierr = PetscObjectGetComm((PetscObject) dm, &comm);CHKERRQ(ierr);
1560   ierr = DMGetDimension(dm, &dim);CHKERRQ(ierr);
1561   ierr = DMSetDimension(targetDM, dim);CHKERRQ(ierr);
1562 
1563   /* Check for a one-to-all distribution pattern */
1564   ierr = DMGetPointSF(dm, &sfPoint);CHKERRQ(ierr);
1565   ierr = PetscSFGetGraph(sfPoint, &nroots, NULL, NULL, NULL);CHKERRQ(ierr);
1566   if (nroots >= 0) {
1567     IS                     isOriginal;
1568     PetscInt               n, size, nleaves;
1569     PetscInt              *numbering_orig, *numbering_new;
1570     /* Get the original point numbering */
1571     ierr = DMPlexCreatePointNumbering(dm, &isOriginal);CHKERRQ(ierr);
1572     ierr = ISLocalToGlobalMappingCreateIS(isOriginal, &ltogOriginal);CHKERRQ(ierr);
1573     ierr = ISLocalToGlobalMappingGetSize(ltogOriginal, &size);CHKERRQ(ierr);
1574     ierr = ISLocalToGlobalMappingGetBlockIndices(ltogOriginal, (const PetscInt**)&numbering_orig);CHKERRQ(ierr);
1575     /* Convert to positive global numbers */
1576     for (n=0; n<size; n++) {if (numbering_orig[n] < 0) numbering_orig[n] = -(numbering_orig[n]+1);}
1577     /* Derive the new local-to-global mapping from the old one */
1578     ierr = PetscSFGetGraph(sf, NULL, &nleaves, NULL, NULL);CHKERRQ(ierr);
1579     ierr = PetscMalloc1(nleaves, &numbering_new);CHKERRQ(ierr);
1580     ierr = PetscSFBcastBegin(sf, MPIU_INT, (PetscInt *) numbering_orig, numbering_new);CHKERRQ(ierr);
1581     ierr = PetscSFBcastEnd(sf, MPIU_INT, (PetscInt *) numbering_orig, numbering_new);CHKERRQ(ierr);
1582     ierr = ISLocalToGlobalMappingCreate(comm, 1, nleaves, (const PetscInt*) numbering_new, PETSC_OWN_POINTER, &ltogMigration);CHKERRQ(ierr);
1583     ierr = ISLocalToGlobalMappingRestoreIndices(ltogOriginal, (const PetscInt**)&numbering_orig);CHKERRQ(ierr);
1584     ierr = ISDestroy(&isOriginal);CHKERRQ(ierr);
1585   } else {
1586     /* One-to-all distribution pattern: We can derive LToG from SF */
1587     ierr = ISLocalToGlobalMappingCreateSF(sf, 0, &ltogMigration);CHKERRQ(ierr);
1588   }
1589   ierr = PetscOptionsHasName(((PetscObject) dm)->options,((PetscObject) dm)->prefix, "-partition_view", &flg);CHKERRQ(ierr);
1590   if (flg) {
1591     ierr = PetscPrintf(comm, "Point renumbering for DM migration:\n");CHKERRQ(ierr);
1592     ierr = ISLocalToGlobalMappingView(ltogMigration, NULL);CHKERRQ(ierr);
1593   }
1594   /* Migrate DM data to target DM */
1595   ierr = DMPlexDistributeCones(dm, sf, ltogOriginal, ltogMigration, targetDM);CHKERRQ(ierr);
1596   ierr = DMPlexDistributeLabels(dm, sf, targetDM);CHKERRQ(ierr);
1597   ierr = DMPlexDistributeCoordinates(dm, sf, targetDM);CHKERRQ(ierr);
1598   ierr = DMPlexDistributeSetupHybrid(dm, sf, ltogMigration, targetDM);CHKERRQ(ierr);
1599   ierr = DMPlexDistributeSetupTree(dm, sf, ltogOriginal, ltogMigration, targetDM);CHKERRQ(ierr);
1600   ierr = ISLocalToGlobalMappingDestroy(&ltogOriginal);CHKERRQ(ierr);
1601   ierr = ISLocalToGlobalMappingDestroy(&ltogMigration);CHKERRQ(ierr);
1602   ierr = PetscLogEventEnd(DMPLEX_Migrate, dm, 0, 0, 0);CHKERRQ(ierr);
1603   PetscFunctionReturn(0);
1604 }
1605 
1606 /*@C
1607   DMPlexDistribute - Distributes the mesh and any associated sections.
1608 
1609   Not Collective
1610 
1611   Input Parameter:
1612 + dm  - The original DMPlex object
1613 - overlap - The overlap of partitions, 0 is the default
1614 
1615   Output Parameter:
1616 + sf - The PetscSF used for point distribution
1617 - parallelMesh - The distributed DMPlex object, or NULL
1618 
1619   Note: If the mesh was not distributed, the return value is NULL.
1620 
1621   The user can control the definition of adjacency for the mesh using DMPlexSetAdjacencyUseCone() and
1622   DMPlexSetAdjacencyUseClosure(). They should choose the combination appropriate for the function
1623   representation on the mesh.
1624 
1625   Level: intermediate
1626 
1627 .keywords: mesh, elements
1628 .seealso: DMPlexCreate(), DMPlexDistributeByFace(), DMPlexSetAdjacencyUseCone(), DMPlexSetAdjacencyUseClosure()
1629 @*/
1630 PetscErrorCode DMPlexDistribute(DM dm, PetscInt overlap, PetscSF *sf, DM *dmParallel)
1631 {
1632   MPI_Comm               comm;
1633   PetscPartitioner       partitioner;
1634   IS                     cellPart;
1635   PetscSection           cellPartSection;
1636   DM                     dmCoord;
1637   DMLabel                lblPartition, lblMigration;
1638   PetscSF                sfProcess, sfMigration, sfStratified, sfPoint;
1639   PetscBool              flg;
1640   PetscMPIInt            rank, size, p;
1641   PetscErrorCode         ierr;
1642 
1643   PetscFunctionBegin;
1644   PetscValidHeaderSpecific(dm, DM_CLASSID, 1);
1645   if (sf) PetscValidPointer(sf,4);
1646   PetscValidPointer(dmParallel,5);
1647 
1648   ierr = PetscLogEventBegin(DMPLEX_Distribute,dm,0,0,0);CHKERRQ(ierr);
1649   ierr = PetscObjectGetComm((PetscObject)dm,&comm);CHKERRQ(ierr);
1650   ierr = MPI_Comm_rank(comm, &rank);CHKERRQ(ierr);
1651   ierr = MPI_Comm_size(comm, &size);CHKERRQ(ierr);
1652 
1653   if (sf) *sf = NULL;
1654   *dmParallel = NULL;
1655   if (size == 1) {
1656     ierr = PetscLogEventEnd(DMPLEX_Distribute,dm,0,0,0);CHKERRQ(ierr);
1657     PetscFunctionReturn(0);
1658   }
1659 
1660   /* Create cell partition */
1661   ierr = PetscLogEventBegin(PETSCPARTITIONER_Partition,dm,0,0,0);CHKERRQ(ierr);
1662   ierr = PetscSectionCreate(comm, &cellPartSection);CHKERRQ(ierr);
1663   ierr = DMPlexGetPartitioner(dm, &partitioner);CHKERRQ(ierr);
1664   ierr = PetscPartitionerPartition(partitioner, dm, cellPartSection, &cellPart);CHKERRQ(ierr);
1665   {
1666     /* Convert partition to DMLabel */
1667     PetscInt proc, pStart, pEnd, npoints, poffset;
1668     const PetscInt *points;
1669     ierr = DMLabelCreate("Point Partition", &lblPartition);CHKERRQ(ierr);
1670     ierr = ISGetIndices(cellPart, &points);CHKERRQ(ierr);
1671     ierr = PetscSectionGetChart(cellPartSection, &pStart, &pEnd);CHKERRQ(ierr);
1672     for (proc = pStart; proc < pEnd; proc++) {
1673       ierr = PetscSectionGetDof(cellPartSection, proc, &npoints);CHKERRQ(ierr);
1674       ierr = PetscSectionGetOffset(cellPartSection, proc, &poffset);CHKERRQ(ierr);
1675       for (p = poffset; p < poffset+npoints; p++) {
1676         ierr = DMLabelSetValue(lblPartition, points[p], proc);CHKERRQ(ierr);
1677       }
1678     }
1679     ierr = ISRestoreIndices(cellPart, &points);CHKERRQ(ierr);
1680   }
1681   ierr = DMPlexPartitionLabelClosure(dm, lblPartition);CHKERRQ(ierr);
1682   {
1683     /* Build a global process SF */
1684     PetscSFNode *remoteProc;
1685     ierr = PetscMalloc1(size, &remoteProc);CHKERRQ(ierr);
1686     for (p = 0; p < size; ++p) {
1687       remoteProc[p].rank  = p;
1688       remoteProc[p].index = rank;
1689     }
1690     ierr = PetscSFCreate(comm, &sfProcess);CHKERRQ(ierr);
1691     ierr = PetscObjectSetName((PetscObject) sfProcess, "Process SF");CHKERRQ(ierr);
1692     ierr = PetscSFSetGraph(sfProcess, size, size, NULL, PETSC_OWN_POINTER, remoteProc, PETSC_OWN_POINTER);CHKERRQ(ierr);
1693   }
1694   ierr = DMLabelCreate("Point migration", &lblMigration);CHKERRQ(ierr);
1695   ierr = DMPlexPartitionLabelInvert(dm, lblPartition, sfProcess, lblMigration);CHKERRQ(ierr);
1696   ierr = DMPlexPartitionLabelCreateSF(dm, lblMigration, &sfMigration);CHKERRQ(ierr);
1697   /* Stratify the SF in case we are migrating an already parallel plex */
1698   ierr = DMPlexStratifyMigrationSF(dm, sfMigration, &sfStratified);CHKERRQ(ierr);
1699   ierr = PetscSFDestroy(&sfMigration);CHKERRQ(ierr);
1700   sfMigration = sfStratified;
1701   ierr = PetscLogEventEnd(PETSCPARTITIONER_Partition,dm,0,0,0);CHKERRQ(ierr);
1702   ierr = PetscOptionsHasName(((PetscObject) dm)->options,((PetscObject) dm)->prefix, "-partition_view", &flg);CHKERRQ(ierr);
1703   if (flg) {
1704     ierr = DMLabelView(lblPartition, PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
1705     ierr = PetscSFView(sfMigration, PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
1706   }
1707 
1708   /* Create non-overlapping parallel DM and migrate internal data */
1709   ierr = DMPlexCreate(comm, dmParallel);CHKERRQ(ierr);
1710   ierr = PetscObjectSetName((PetscObject) *dmParallel, "Parallel Mesh");CHKERRQ(ierr);
1711   ierr = DMPlexMigrate(dm, sfMigration, *dmParallel);CHKERRQ(ierr);
1712 
1713   /* Build the point SF without overlap */
1714   ierr = DMPlexCreatePointSF(*dmParallel, sfMigration, PETSC_TRUE, &sfPoint);CHKERRQ(ierr);
1715   ierr = DMSetPointSF(*dmParallel, sfPoint);CHKERRQ(ierr);
1716   ierr = DMGetCoordinateDM(*dmParallel, &dmCoord);CHKERRQ(ierr);
1717   if (dmCoord) {ierr = DMSetPointSF(dmCoord, sfPoint);CHKERRQ(ierr);}
1718   if (flg) {ierr = PetscSFView(sfPoint, PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);}
1719 
1720   if (overlap > 0) {
1721     DM                 dmOverlap;
1722     PetscInt           nroots, nleaves;
1723     PetscSFNode       *newRemote;
1724     const PetscSFNode *oldRemote;
1725     PetscSF            sfOverlap, sfOverlapPoint;
1726     /* Add the partition overlap to the distributed DM */
1727     ierr = DMPlexDistributeOverlap(*dmParallel, overlap, &sfOverlap, &dmOverlap);CHKERRQ(ierr);
1728     ierr = DMDestroy(dmParallel);CHKERRQ(ierr);
1729     *dmParallel = dmOverlap;
1730     if (flg) {
1731       ierr = PetscPrintf(comm, "Overlap Migration SF:\n");CHKERRQ(ierr);
1732       ierr = PetscSFView(sfOverlap, NULL);CHKERRQ(ierr);
1733     }
1734 
1735     /* Re-map the migration SF to establish the full migration pattern */
1736     ierr = PetscSFGetGraph(sfMigration, &nroots, NULL, NULL, &oldRemote);CHKERRQ(ierr);
1737     ierr = PetscSFGetGraph(sfOverlap, NULL, &nleaves, NULL, NULL);CHKERRQ(ierr);
1738     ierr = PetscMalloc1(nleaves, &newRemote);CHKERRQ(ierr);
1739     ierr = PetscSFBcastBegin(sfOverlap, MPIU_2INT, oldRemote, newRemote);CHKERRQ(ierr);
1740     ierr = PetscSFBcastEnd(sfOverlap, MPIU_2INT, oldRemote, newRemote);CHKERRQ(ierr);
1741     ierr = PetscSFCreate(comm, &sfOverlapPoint);CHKERRQ(ierr);
1742     ierr = PetscSFSetGraph(sfOverlapPoint, nroots, nleaves, NULL, PETSC_OWN_POINTER, newRemote, PETSC_OWN_POINTER);CHKERRQ(ierr);
1743     ierr = PetscSFDestroy(&sfOverlap);CHKERRQ(ierr);
1744     ierr = PetscSFDestroy(&sfMigration);CHKERRQ(ierr);
1745     sfMigration = sfOverlapPoint;
1746   }
1747   /* Cleanup Partition */
1748   ierr = PetscSFDestroy(&sfProcess);CHKERRQ(ierr);
1749   ierr = DMLabelDestroy(&lblPartition);CHKERRQ(ierr);
1750   ierr = DMLabelDestroy(&lblMigration);CHKERRQ(ierr);
1751   ierr = PetscSectionDestroy(&cellPartSection);CHKERRQ(ierr);
1752   ierr = ISDestroy(&cellPart);CHKERRQ(ierr);
1753   /* Copy BC */
1754   ierr = DMCopyBoundary(dm, *dmParallel);CHKERRQ(ierr);
1755   /* Create sfNatural */
1756   if (dm->useNatural) {
1757     PetscSection section;
1758 
1759     ierr = DMGetDefaultSection(dm, &section);CHKERRQ(ierr);
1760     ierr = DMPlexCreateGlobalToNaturalSF(*dmParallel, section, sfMigration, &(*dmParallel)->sfNatural);CHKERRQ(ierr);
1761     ierr = DMSetUseNatural(*dmParallel, PETSC_TRUE);CHKERRQ(ierr);
1762   }
1763   /* Cleanup */
1764   if (sf) {*sf = sfMigration;}
1765   else    {ierr = PetscSFDestroy(&sfMigration);CHKERRQ(ierr);}
1766   ierr = PetscSFDestroy(&sfPoint);CHKERRQ(ierr);
1767   ierr = PetscLogEventEnd(DMPLEX_Distribute,dm,0,0,0);CHKERRQ(ierr);
1768   PetscFunctionReturn(0);
1769 }
1770 
1771 /*@C
1772   DMPlexDistributeOverlap - Add partition overlap to a distributed non-overlapping DM.
1773 
1774   Not Collective
1775 
1776   Input Parameter:
1777 + dm  - The non-overlapping distrbuted DMPlex object
1778 - overlap - The overlap of partitions, 0 is the default
1779 
1780   Output Parameter:
1781 + sf - The PetscSF used for point distribution
1782 - dmOverlap - The overlapping distributed DMPlex object, or NULL
1783 
1784   Note: If the mesh was not distributed, the return value is NULL.
1785 
1786   The user can control the definition of adjacency for the mesh using DMPlexGetAdjacencyUseCone() and
1787   DMPlexSetAdjacencyUseClosure(). They should choose the combination appropriate for the function
1788   representation on the mesh.
1789 
1790   Level: intermediate
1791 
1792 .keywords: mesh, elements
1793 .seealso: DMPlexCreate(), DMPlexDistributeByFace(), DMPlexSetAdjacencyUseCone(), DMPlexSetAdjacencyUseClosure()
1794 @*/
1795 PetscErrorCode DMPlexDistributeOverlap(DM dm, PetscInt overlap, PetscSF *sf, DM *dmOverlap)
1796 {
1797   MPI_Comm               comm;
1798   PetscMPIInt            size, rank;
1799   PetscSection           rootSection, leafSection;
1800   IS                     rootrank, leafrank;
1801   DM                     dmCoord;
1802   DMLabel                lblOverlap;
1803   PetscSF                sfOverlap, sfStratified, sfPoint;
1804   PetscErrorCode         ierr;
1805 
1806   PetscFunctionBegin;
1807   PetscValidHeaderSpecific(dm, DM_CLASSID, 1);
1808   if (sf) PetscValidPointer(sf, 3);
1809   PetscValidPointer(dmOverlap, 4);
1810 
1811   ierr = PetscObjectGetComm((PetscObject)dm,&comm);CHKERRQ(ierr);
1812   ierr = MPI_Comm_size(comm, &size);CHKERRQ(ierr);
1813   ierr = MPI_Comm_rank(comm, &rank);CHKERRQ(ierr);
1814   if (size == 1) {*dmOverlap = NULL; PetscFunctionReturn(0);}
1815   ierr = PetscLogEventBegin(DMPLEX_DistributeOverlap, dm, 0, 0, 0);CHKERRQ(ierr);
1816 
1817   /* Compute point overlap with neighbouring processes on the distributed DM */
1818   ierr = PetscLogEventBegin(PETSCPARTITIONER_Partition,dm,0,0,0);CHKERRQ(ierr);
1819   ierr = PetscSectionCreate(comm, &rootSection);CHKERRQ(ierr);
1820   ierr = PetscSectionCreate(comm, &leafSection);CHKERRQ(ierr);
1821   ierr = DMPlexDistributeOwnership(dm, rootSection, &rootrank, leafSection, &leafrank);CHKERRQ(ierr);
1822   ierr = DMPlexCreateOverlap(dm, overlap, rootSection, rootrank, leafSection, leafrank, &lblOverlap);CHKERRQ(ierr);
1823   /* Convert overlap label to stratified migration SF */
1824   ierr = DMPlexPartitionLabelCreateSF(dm, lblOverlap, &sfOverlap);CHKERRQ(ierr);
1825   ierr = DMPlexStratifyMigrationSF(dm, sfOverlap, &sfStratified);CHKERRQ(ierr);
1826   ierr = PetscSFDestroy(&sfOverlap);CHKERRQ(ierr);
1827   sfOverlap = sfStratified;
1828   ierr = PetscObjectSetName((PetscObject) sfOverlap, "Overlap SF");CHKERRQ(ierr);
1829   ierr = PetscSFSetFromOptions(sfOverlap);CHKERRQ(ierr);
1830 
1831   ierr = PetscSectionDestroy(&rootSection);CHKERRQ(ierr);
1832   ierr = PetscSectionDestroy(&leafSection);CHKERRQ(ierr);
1833   ierr = ISDestroy(&rootrank);CHKERRQ(ierr);
1834   ierr = ISDestroy(&leafrank);CHKERRQ(ierr);
1835   ierr = PetscLogEventEnd(PETSCPARTITIONER_Partition,dm,0,0,0);CHKERRQ(ierr);
1836 
1837   /* Build the overlapping DM */
1838   ierr = DMPlexCreate(comm, dmOverlap);CHKERRQ(ierr);
1839   ierr = PetscObjectSetName((PetscObject) *dmOverlap, "Parallel Mesh");CHKERRQ(ierr);
1840   ierr = DMPlexMigrate(dm, sfOverlap, *dmOverlap);CHKERRQ(ierr);
1841   /* Build the new point SF */
1842   ierr = DMPlexCreatePointSF(*dmOverlap, sfOverlap, PETSC_FALSE, &sfPoint);CHKERRQ(ierr);
1843   ierr = DMSetPointSF(*dmOverlap, sfPoint);CHKERRQ(ierr);
1844   ierr = DMGetCoordinateDM(*dmOverlap, &dmCoord);CHKERRQ(ierr);
1845   if (dmCoord) {ierr = DMSetPointSF(dmCoord, sfPoint);CHKERRQ(ierr);}
1846   ierr = PetscSFDestroy(&sfPoint);CHKERRQ(ierr);
1847   /* Cleanup overlap partition */
1848   ierr = DMLabelDestroy(&lblOverlap);CHKERRQ(ierr);
1849   if (sf) *sf = sfOverlap;
1850   else    {ierr = PetscSFDestroy(&sfOverlap);CHKERRQ(ierr);}
1851   ierr = PetscLogEventEnd(DMPLEX_DistributeOverlap, dm, 0, 0, 0);CHKERRQ(ierr);
1852   PetscFunctionReturn(0);
1853 }
1854 
1855 /*@C
1856   DMPlexGetGatherDM - Get a copy of the DMPlex that gathers all points on the
1857   root process of the original's communicator.
1858 
1859   Input Parameters:
1860 . dm - the original DMPlex object
1861 
1862   Output Parameters:
1863 . gatherMesh - the gathered DM object, or NULL
1864 
1865   Level: intermediate
1866 
1867 .keywords: mesh
1868 .seealso: DMPlexDistribute(), DMPlexGetRedundantDM()
1869 @*/
1870 PetscErrorCode DMPlexGetGatherDM(DM dm, DM * gatherMesh)
1871 {
1872   MPI_Comm       comm;
1873   PetscMPIInt    size;
1874   PetscPartitioner oldPart, gatherPart;
1875   PetscErrorCode ierr;
1876 
1877   PetscFunctionBegin;
1878   PetscValidHeaderSpecific(dm,DM_CLASSID,1);
1879   comm = PetscObjectComm((PetscObject)dm);
1880   ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
1881   *gatherMesh = NULL;
1882   if (size == 1) PetscFunctionReturn(0);
1883   ierr = DMPlexGetPartitioner(dm,&oldPart);CHKERRQ(ierr);
1884   ierr = PetscObjectReference((PetscObject)oldPart);CHKERRQ(ierr);
1885   ierr = PetscPartitionerCreate(comm,&gatherPart);CHKERRQ(ierr);
1886   ierr = PetscPartitionerSetType(gatherPart,PETSCPARTITIONERGATHER);CHKERRQ(ierr);
1887   ierr = DMPlexSetPartitioner(dm,gatherPart);CHKERRQ(ierr);
1888   ierr = DMPlexDistribute(dm,0,NULL,gatherMesh);CHKERRQ(ierr);
1889   ierr = DMPlexSetPartitioner(dm,oldPart);CHKERRQ(ierr);
1890   ierr = PetscPartitionerDestroy(&gatherPart);CHKERRQ(ierr);
1891   ierr = PetscPartitionerDestroy(&oldPart);CHKERRQ(ierr);
1892   PetscFunctionReturn(0);
1893 }
1894 
1895 /*@C
1896   DMPlexGetRedundantDM - Get a copy of the DMPlex that is completely copied on each process.
1897 
1898   Input Parameters:
1899 . dm - the original DMPlex object
1900 
1901   Output Parameters:
1902 . redundantMesh - the redundant DM object, or NULL
1903 
1904   Level: intermediate
1905 
1906 .keywords: mesh
1907 .seealso: DMPlexDistribute(), DMPlexGetGatherDM()
1908 @*/
1909 PetscErrorCode DMPlexGetRedundantDM(DM dm, DM * redundantMesh)
1910 {
1911   MPI_Comm       comm;
1912   PetscMPIInt    size, rank;
1913   PetscInt       pStart, pEnd, p;
1914   PetscInt       numPoints = -1;
1915   PetscSF        migrationSF, sfPoint;
1916   DM             gatherDM, dmCoord;
1917   PetscSFNode    *points;
1918   PetscErrorCode ierr;
1919 
1920   PetscFunctionBegin;
1921   PetscValidHeaderSpecific(dm,DM_CLASSID,1);
1922   comm = PetscObjectComm((PetscObject)dm);
1923   ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
1924   *redundantMesh = NULL;
1925   if (size == 1) {
1926     ierr = PetscObjectReference((PetscObject) dm);CHKERRQ(ierr);
1927     *redundantMesh = dm;
1928     PetscFunctionReturn(0);
1929   }
1930   ierr = DMPlexGetGatherDM(dm,&gatherDM);CHKERRQ(ierr);
1931   if (!gatherDM) PetscFunctionReturn(0);
1932   ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr);
1933   ierr = DMPlexGetChart(gatherDM,&pStart,&pEnd);CHKERRQ(ierr);
1934   numPoints = pEnd - pStart;
1935   ierr = MPI_Bcast(&numPoints,1,MPIU_INT,0,comm);CHKERRQ(ierr);
1936   ierr = PetscMalloc1(numPoints,&points);CHKERRQ(ierr);
1937   ierr = PetscSFCreate(comm,&migrationSF);CHKERRQ(ierr);
1938   for (p = 0; p < numPoints; p++) {
1939     points[p].index = p;
1940     points[p].rank  = 0;
1941   }
1942   ierr = PetscSFSetGraph(migrationSF,pEnd-pStart,numPoints,NULL,PETSC_OWN_POINTER,points,PETSC_OWN_POINTER);CHKERRQ(ierr);
1943   ierr = DMPlexCreate(comm, redundantMesh);CHKERRQ(ierr);
1944   ierr = PetscObjectSetName((PetscObject) *redundantMesh, "Redundant Mesh");CHKERRQ(ierr);
1945   ierr = DMPlexMigrate(gatherDM, migrationSF, *redundantMesh);CHKERRQ(ierr);
1946   ierr = DMPlexCreatePointSF(*redundantMesh, migrationSF, PETSC_FALSE, &sfPoint);CHKERRQ(ierr);
1947   ierr = DMSetPointSF(*redundantMesh, sfPoint);CHKERRQ(ierr);
1948   ierr = DMGetCoordinateDM(*redundantMesh, &dmCoord);CHKERRQ(ierr);
1949   if (dmCoord) {ierr = DMSetPointSF(dmCoord, sfPoint);CHKERRQ(ierr);}
1950   ierr = PetscSFDestroy(&sfPoint);CHKERRQ(ierr);
1951   ierr = PetscSFDestroy(&migrationSF);CHKERRQ(ierr);
1952   ierr = DMDestroy(&gatherDM);CHKERRQ(ierr);
1953   PetscFunctionReturn(0);
1954 }
1955