xref: /petsc/src/dm/impls/plex/plexsubmesh.c (revision c5b75c40f2b03d062403f886ebcfc3786a9d710b)
1 #include <petsc-private/dmpleximpl.h>   /*I      "petscdmplex.h"   I*/
2 
3 #undef __FUNCT__
4 #define __FUNCT__ "DMPlexMarkBoundaryFaces"
5 /*@
6   DMPlexMarkBoundaryFaces - Mark all faces on the boundary
7 
8   Not Collective
9 
10   Input Parameter:
11 . dm - The original DM
12 
13   Output Parameter:
14 . label - The DMLabel marking boundary faces with value 1
15 
16   Level: developer
17 
18 .seealso: DMLabelCreate(), DMPlexCreateLabel()
19 @*/
20 PetscErrorCode DMPlexMarkBoundaryFaces(DM dm, DMLabel label)
21 {
22   PetscInt       fStart, fEnd, f;
23   PetscErrorCode ierr;
24 
25   PetscFunctionBegin;
26   PetscValidHeaderSpecific(dm, DM_CLASSID, 1);
27   ierr = DMPlexGetHeightStratum(dm, 1, &fStart, &fEnd);CHKERRQ(ierr);
28   for (f = fStart; f < fEnd; ++f) {
29     PetscInt supportSize;
30 
31     ierr = DMPlexGetSupportSize(dm, f, &supportSize);CHKERRQ(ierr);
32     if (supportSize == 1) {
33       ierr = DMLabelSetValue(label, f, 1);CHKERRQ(ierr);
34     }
35   }
36   PetscFunctionReturn(0);
37 }
38 
39 #undef __FUNCT__
40 #define __FUNCT__ "DMPlexLabelComplete"
41 /*@
42   DMPlexLabelComplete - Starting with a label marking points on a surface, we add the transitive closure to the surface
43 
44   Input Parameters:
45 + dm - The DM
46 - label - A DMLabel marking the surface points
47 
48   Output Parameter:
49 . label - A DMLabel marking all surface points in the transitive closure
50 
51   Level: developer
52 
53 .seealso: DMPlexLabelCohesiveComplete()
54 @*/
55 PetscErrorCode DMPlexLabelComplete(DM dm, DMLabel label)
56 {
57   IS              valueIS;
58   const PetscInt *values;
59   PetscInt        numValues, v;
60   PetscErrorCode  ierr;
61 
62   PetscFunctionBegin;
63   ierr = DMLabelGetNumValues(label, &numValues);CHKERRQ(ierr);
64   ierr = DMLabelGetValueIS(label, &valueIS);CHKERRQ(ierr);
65   ierr = ISGetIndices(valueIS, &values);CHKERRQ(ierr);
66   for (v = 0; v < numValues; ++v) {
67     IS              pointIS;
68     const PetscInt *points;
69     PetscInt        numPoints, p;
70 
71     ierr = DMLabelGetStratumSize(label, values[v], &numPoints);CHKERRQ(ierr);
72     ierr = DMLabelGetStratumIS(label, values[v], &pointIS);CHKERRQ(ierr);
73     ierr = ISGetIndices(pointIS, &points);CHKERRQ(ierr);
74     for (p = 0; p < numPoints; ++p) {
75       PetscInt *closure = NULL;
76       PetscInt  closureSize, c;
77 
78       ierr = DMPlexGetTransitiveClosure(dm, points[p], PETSC_TRUE, &closureSize, &closure);CHKERRQ(ierr);
79       for (c = 0; c < closureSize*2; c += 2) {
80         ierr = DMLabelSetValue(label, closure[c], values[v]);CHKERRQ(ierr);
81       }
82       ierr = DMPlexRestoreTransitiveClosure(dm, points[p], PETSC_TRUE, &closureSize, &closure);CHKERRQ(ierr);
83     }
84     ierr = ISRestoreIndices(pointIS, &points);CHKERRQ(ierr);
85     ierr = ISDestroy(&pointIS);CHKERRQ(ierr);
86   }
87   ierr = ISRestoreIndices(valueIS, &values);CHKERRQ(ierr);
88   ierr = ISDestroy(&valueIS);CHKERRQ(ierr);
89   PetscFunctionReturn(0);
90 }
91 
92 #undef __FUNCT__
93 #define __FUNCT__ "DMPlexShiftPoint_Internal"
94 PETSC_STATIC_INLINE PetscInt DMPlexShiftPoint_Internal(PetscInt p, PetscInt depth, PetscInt depthEnd[], PetscInt depthShift[])
95 {
96   if (depth < 0) return p;
97   /* Cells    */ if (p < depthEnd[depth])   return p;
98   /* Vertices */ if (p < depthEnd[0])       return p + depthShift[depth];
99   /* Faces    */ if (p < depthEnd[depth-1]) return p + depthShift[depth] + depthShift[0];
100   /* Edges    */                            return p + depthShift[depth] + depthShift[0] + depthShift[depth-1];
101 }
102 
103 #undef __FUNCT__
104 #define __FUNCT__ "DMPlexShiftSizes_Internal"
105 static PetscErrorCode DMPlexShiftSizes_Internal(DM dm, PetscInt depthShift[], DM dmNew)
106 {
107   PetscInt      *depthEnd;
108   PetscInt       depth = 0, d, pStart, pEnd, p;
109   PetscErrorCode ierr;
110 
111   PetscFunctionBegin;
112   ierr = DMPlexGetDepth(dm, &depth);CHKERRQ(ierr);
113   if (depth < 0) PetscFunctionReturn(0);
114   ierr = PetscMalloc((depth+1) * sizeof(PetscInt), &depthEnd);CHKERRQ(ierr);
115   /* Step 1: Expand chart */
116   ierr = DMPlexGetChart(dm, &pStart, &pEnd);CHKERRQ(ierr);
117   for (d = 0; d <= depth; ++d) {
118     pEnd += depthShift[d];
119     ierr  = DMPlexGetDepthStratum(dm, d, NULL, &depthEnd[d]);CHKERRQ(ierr);
120   }
121   ierr = DMPlexSetChart(dmNew, pStart, pEnd);CHKERRQ(ierr);
122   /* Step 2: Set cone and support sizes */
123   for (d = 0; d <= depth; ++d) {
124     ierr = DMPlexGetDepthStratum(dm, d, &pStart, &pEnd);CHKERRQ(ierr);
125     for (p = pStart; p < pEnd; ++p) {
126       PetscInt newp = DMPlexShiftPoint_Internal(p, depth, depthEnd, depthShift);
127       PetscInt size;
128 
129       ierr = DMPlexGetConeSize(dm, p, &size);CHKERRQ(ierr);
130       ierr = DMPlexSetConeSize(dmNew, newp, size);CHKERRQ(ierr);
131       ierr = DMPlexGetSupportSize(dm, p, &size);CHKERRQ(ierr);
132       ierr = DMPlexSetSupportSize(dmNew, newp, size);CHKERRQ(ierr);
133     }
134   }
135   ierr = PetscFree(depthEnd);CHKERRQ(ierr);
136   PetscFunctionReturn(0);
137 }
138 
139 #undef __FUNCT__
140 #define __FUNCT__ "DMPlexShiftPoints_Internal"
141 static PetscErrorCode DMPlexShiftPoints_Internal(DM dm, PetscInt depthShift[], DM dmNew)
142 {
143   PetscInt      *depthEnd, *newpoints;
144   PetscInt       depth = 0, d, maxConeSize, maxSupportSize, pStart, pEnd, p;
145   PetscErrorCode ierr;
146 
147   PetscFunctionBegin;
148   ierr = DMPlexGetDepth(dm, &depth);CHKERRQ(ierr);
149   if (depth < 0) PetscFunctionReturn(0);
150   ierr = DMPlexGetMaxSizes(dm, &maxConeSize, &maxSupportSize);CHKERRQ(ierr);
151   ierr = PetscMalloc2(depth+1,PetscInt,&depthEnd,PetscMax(maxConeSize, maxSupportSize),PetscInt,&newpoints);CHKERRQ(ierr);
152   for (d = 0; d <= depth; ++d) {
153     ierr = DMPlexGetDepthStratum(dm, d, NULL, &depthEnd[d]);CHKERRQ(ierr);
154   }
155   /* Step 5: Set cones and supports */
156   ierr = DMPlexGetChart(dm, &pStart, &pEnd);CHKERRQ(ierr);
157   for (p = pStart; p < pEnd; ++p) {
158     const PetscInt *points = NULL, *orientations = NULL;
159     PetscInt        size, i, newp = DMPlexShiftPoint_Internal(p, depth, depthEnd, depthShift);
160 
161     ierr = DMPlexGetConeSize(dm, p, &size);CHKERRQ(ierr);
162     ierr = DMPlexGetCone(dm, p, &points);CHKERRQ(ierr);
163     ierr = DMPlexGetConeOrientation(dm, p, &orientations);CHKERRQ(ierr);
164     for (i = 0; i < size; ++i) {
165       newpoints[i] = DMPlexShiftPoint_Internal(points[i], depth, depthEnd, depthShift);
166     }
167     ierr = DMPlexSetCone(dmNew, newp, newpoints);CHKERRQ(ierr);
168     ierr = DMPlexSetConeOrientation(dmNew, newp, orientations);CHKERRQ(ierr);
169     ierr = DMPlexGetSupportSize(dm, p, &size);CHKERRQ(ierr);
170     ierr = DMPlexGetSupport(dm, p, &points);CHKERRQ(ierr);
171     for (i = 0; i < size; ++i) {
172       newpoints[i] = DMPlexShiftPoint_Internal(points[i], depth, depthEnd, depthShift);
173     }
174     ierr = DMPlexSetSupport(dmNew, newp, newpoints);CHKERRQ(ierr);
175   }
176   ierr = PetscFree2(depthEnd,newpoints);CHKERRQ(ierr);
177   PetscFunctionReturn(0);
178 }
179 
180 #undef __FUNCT__
181 #define __FUNCT__ "DMPlexShiftCoordinates_Internal"
182 static PetscErrorCode DMPlexShiftCoordinates_Internal(DM dm, PetscInt depthShift[], DM dmNew)
183 {
184   PetscSection   coordSection, newCoordSection;
185   Vec            coordinates, newCoordinates;
186   PetscScalar   *coords, *newCoords;
187   PetscInt      *depthEnd, coordSize;
188   PetscInt       dim, depth = 0, d, vStart, vEnd, vStartNew, vEndNew, v;
189   PetscErrorCode ierr;
190 
191   PetscFunctionBegin;
192   ierr = DMPlexGetDimension(dm, &dim);CHKERRQ(ierr);
193   ierr = DMPlexGetDepth(dm, &depth);CHKERRQ(ierr);
194   ierr = PetscMalloc((depth+1) * sizeof(PetscInt), &depthEnd);CHKERRQ(ierr);
195   for (d = 0; d <= depth; ++d) {
196     ierr = DMPlexGetDepthStratum(dm, d, NULL, &depthEnd[d]);CHKERRQ(ierr);
197   }
198   /* Step 8: Convert coordinates */
199   ierr = DMPlexGetDepthStratum(dm, 0, &vStart, &vEnd);CHKERRQ(ierr);
200   ierr = DMPlexGetDepthStratum(dmNew, 0, &vStartNew, &vEndNew);CHKERRQ(ierr);
201   ierr = DMPlexGetCoordinateSection(dm, &coordSection);CHKERRQ(ierr);
202   ierr = PetscSectionCreate(PetscObjectComm((PetscObject)dm), &newCoordSection);CHKERRQ(ierr);
203   ierr = PetscSectionSetNumFields(newCoordSection, 1);CHKERRQ(ierr);
204   ierr = PetscSectionSetFieldComponents(newCoordSection, 0, dim);CHKERRQ(ierr);
205   ierr = PetscSectionSetChart(newCoordSection, vStartNew, vEndNew);CHKERRQ(ierr);
206   for (v = vStartNew; v < vEndNew; ++v) {
207     ierr = PetscSectionSetDof(newCoordSection, v, dim);CHKERRQ(ierr);
208     ierr = PetscSectionSetFieldDof(newCoordSection, v, 0, dim);CHKERRQ(ierr);
209   }
210   ierr = PetscSectionSetUp(newCoordSection);CHKERRQ(ierr);
211   ierr = DMPlexSetCoordinateSection(dmNew, newCoordSection);CHKERRQ(ierr);
212   ierr = PetscSectionGetStorageSize(newCoordSection, &coordSize);CHKERRQ(ierr);
213   ierr = VecCreate(PetscObjectComm((PetscObject)dm), &newCoordinates);CHKERRQ(ierr);
214   ierr = PetscObjectSetName((PetscObject) newCoordinates, "coordinates");CHKERRQ(ierr);
215   ierr = VecSetSizes(newCoordinates, coordSize, PETSC_DETERMINE);CHKERRQ(ierr);
216   ierr = VecSetFromOptions(newCoordinates);CHKERRQ(ierr);
217   ierr = DMSetCoordinatesLocal(dmNew, newCoordinates);CHKERRQ(ierr);
218   ierr = DMGetCoordinatesLocal(dm, &coordinates);CHKERRQ(ierr);
219   ierr = VecGetArray(coordinates, &coords);CHKERRQ(ierr);
220   ierr = VecGetArray(newCoordinates, &newCoords);CHKERRQ(ierr);
221   for (v = vStart; v < vEnd; ++v) {
222     PetscInt dof, off, noff, d;
223 
224     ierr = PetscSectionGetDof(coordSection, v, &dof);CHKERRQ(ierr);
225     ierr = PetscSectionGetOffset(coordSection, v, &off);CHKERRQ(ierr);
226     ierr = PetscSectionGetOffset(newCoordSection, DMPlexShiftPoint_Internal(v, depth, depthEnd, depthShift), &noff);CHKERRQ(ierr);
227     for (d = 0; d < dof; ++d) {
228       newCoords[noff+d] = coords[off+d];
229     }
230   }
231   ierr = VecRestoreArray(coordinates, &coords);CHKERRQ(ierr);
232   ierr = VecRestoreArray(newCoordinates, &newCoords);CHKERRQ(ierr);
233   ierr = VecDestroy(&newCoordinates);CHKERRQ(ierr);
234   ierr = PetscSectionDestroy(&newCoordSection);CHKERRQ(ierr);
235   ierr = PetscFree(depthEnd);CHKERRQ(ierr);
236   PetscFunctionReturn(0);
237 }
238 
239 #undef __FUNCT__
240 #define __FUNCT__ "DMPlexShiftSF_Internal"
241 static PetscErrorCode DMPlexShiftSF_Internal(DM dm, PetscInt depthShift[], DM dmNew)
242 {
243   PetscInt          *depthEnd;
244   PetscInt           depth = 0, d;
245   PetscSF            sfPoint, sfPointNew;
246   const PetscSFNode *remotePoints;
247   PetscSFNode       *gremotePoints;
248   const PetscInt    *localPoints;
249   PetscInt          *glocalPoints, *newLocation, *newRemoteLocation;
250   PetscInt           numRoots, numLeaves, l, pStart, pEnd, totShift = 0;
251   PetscMPIInt        numProcs;
252   PetscErrorCode     ierr;
253 
254   PetscFunctionBegin;
255   ierr = DMPlexGetDepth(dm, &depth);CHKERRQ(ierr);
256   ierr = PetscMalloc((depth+1) * sizeof(PetscInt), &depthEnd);CHKERRQ(ierr);
257   for (d = 0; d <= depth; ++d) {
258     totShift += depthShift[d];
259     ierr      = DMPlexGetDepthStratum(dm, d, NULL, &depthEnd[d]);CHKERRQ(ierr);
260   }
261   /* Step 9: Convert pointSF */
262   ierr = MPI_Comm_size(PetscObjectComm((PetscObject)dm), &numProcs);CHKERRQ(ierr);
263   ierr = DMGetPointSF(dm, &sfPoint);CHKERRQ(ierr);
264   ierr = DMGetPointSF(dmNew, &sfPointNew);CHKERRQ(ierr);
265   ierr = DMPlexGetChart(dm, &pStart, &pEnd);CHKERRQ(ierr);
266   ierr = PetscSFGetGraph(sfPoint, &numRoots, &numLeaves, &localPoints, &remotePoints);CHKERRQ(ierr);
267   if (numRoots >= 0) {
268     ierr = PetscMalloc2(numRoots,PetscInt,&newLocation,pEnd-pStart,PetscInt,&newRemoteLocation);CHKERRQ(ierr);
269     for (l=0; l<numRoots; l++) newLocation[l] = DMPlexShiftPoint_Internal(l, depth, depthEnd, depthShift);
270     ierr = PetscSFBcastBegin(sfPoint, MPIU_INT, newLocation, newRemoteLocation);CHKERRQ(ierr);
271     ierr = PetscSFBcastEnd(sfPoint, MPIU_INT, newLocation, newRemoteLocation);CHKERRQ(ierr);
272     ierr = PetscMalloc(numLeaves * sizeof(PetscInt),    &glocalPoints);CHKERRQ(ierr);
273     ierr = PetscMalloc(numLeaves * sizeof(PetscSFNode), &gremotePoints);CHKERRQ(ierr);
274     for (l = 0; l < numLeaves; ++l) {
275       glocalPoints[l]        = DMPlexShiftPoint_Internal(localPoints[l], depth, depthEnd, depthShift);
276       gremotePoints[l].rank  = remotePoints[l].rank;
277       gremotePoints[l].index = newRemoteLocation[localPoints[l]];
278     }
279     ierr = PetscFree2(newLocation,newRemoteLocation);CHKERRQ(ierr);
280     ierr = PetscSFSetGraph(sfPointNew, numRoots + totShift, numLeaves, glocalPoints, PETSC_OWN_POINTER, gremotePoints, PETSC_OWN_POINTER);CHKERRQ(ierr);
281   }
282   ierr = PetscFree(depthEnd);CHKERRQ(ierr);
283   PetscFunctionReturn(0);
284 }
285 
286 #undef __FUNCT__
287 #define __FUNCT__ "DMPlexShiftLabels_Internal"
288 static PetscErrorCode DMPlexShiftLabels_Internal(DM dm, PetscInt depthShift[], DM dmNew)
289 {
290   PetscSF            sfPoint;
291   DMLabel            vtkLabel, ghostLabel;
292   PetscInt          *depthEnd;
293   const PetscSFNode *leafRemote;
294   const PetscInt    *leafLocal;
295   PetscInt           depth = 0, d, numLeaves, numLabels, l, cStart, cEnd, c, fStart, fEnd, f;
296   PetscMPIInt        rank;
297   PetscErrorCode     ierr;
298 
299   PetscFunctionBegin;
300   ierr = DMPlexGetDepth(dm, &depth);CHKERRQ(ierr);
301   ierr = PetscMalloc((depth+1) * sizeof(PetscInt), &depthEnd);CHKERRQ(ierr);
302   for (d = 0; d <= depth; ++d) {
303     ierr = DMPlexGetDepthStratum(dm, d, NULL, &depthEnd[d]);CHKERRQ(ierr);
304   }
305   /* Step 10: Convert labels */
306   ierr = DMPlexGetNumLabels(dm, &numLabels);CHKERRQ(ierr);
307   for (l = 0; l < numLabels; ++l) {
308     DMLabel         label, newlabel;
309     const char     *lname;
310     PetscBool       isDepth;
311     IS              valueIS;
312     const PetscInt *values;
313     PetscInt        numValues, val;
314 
315     ierr = DMPlexGetLabelName(dm, l, &lname);CHKERRQ(ierr);
316     ierr = PetscStrcmp(lname, "depth", &isDepth);CHKERRQ(ierr);
317     if (isDepth) continue;
318     ierr = DMPlexCreateLabel(dmNew, lname);CHKERRQ(ierr);
319     ierr = DMPlexGetLabel(dm, lname, &label);CHKERRQ(ierr);
320     ierr = DMPlexGetLabel(dmNew, lname, &newlabel);CHKERRQ(ierr);
321     ierr = DMLabelGetValueIS(label, &valueIS);CHKERRQ(ierr);
322     ierr = ISGetLocalSize(valueIS, &numValues);CHKERRQ(ierr);
323     ierr = ISGetIndices(valueIS, &values);CHKERRQ(ierr);
324     for (val = 0; val < numValues; ++val) {
325       IS              pointIS;
326       const PetscInt *points;
327       PetscInt        numPoints, p;
328 
329       ierr = DMLabelGetStratumIS(label, values[val], &pointIS);CHKERRQ(ierr);
330       ierr = ISGetLocalSize(pointIS, &numPoints);CHKERRQ(ierr);
331       ierr = ISGetIndices(pointIS, &points);CHKERRQ(ierr);
332       for (p = 0; p < numPoints; ++p) {
333         const PetscInt newpoint = DMPlexShiftPoint_Internal(points[p], depth, depthEnd, depthShift);
334 
335         ierr = DMLabelSetValue(newlabel, newpoint, values[val]);CHKERRQ(ierr);
336       }
337       ierr = ISRestoreIndices(pointIS, &points);CHKERRQ(ierr);
338       ierr = ISDestroy(&pointIS);CHKERRQ(ierr);
339     }
340     ierr = ISRestoreIndices(valueIS, &values);CHKERRQ(ierr);
341     ierr = ISDestroy(&valueIS);CHKERRQ(ierr);
342   }
343   ierr = PetscFree(depthEnd);CHKERRQ(ierr);
344   /* Step 11: Make label for output (vtk) and to mark ghost points (ghost) */
345   ierr = MPI_Comm_rank(PetscObjectComm((PetscObject)dm), &rank);CHKERRQ(ierr);
346   ierr = DMGetPointSF(dm, &sfPoint);CHKERRQ(ierr);
347   ierr = DMPlexGetHeightStratum(dm, 0, &cStart, &cEnd);CHKERRQ(ierr);
348   ierr = PetscSFGetGraph(sfPoint, NULL, &numLeaves, &leafLocal, &leafRemote);CHKERRQ(ierr);
349   ierr = DMPlexCreateLabel(dmNew, "vtk");CHKERRQ(ierr);
350   ierr = DMPlexCreateLabel(dmNew, "ghost");CHKERRQ(ierr);
351   ierr = DMPlexGetLabel(dmNew, "vtk", &vtkLabel);CHKERRQ(ierr);
352   ierr = DMPlexGetLabel(dmNew, "ghost", &ghostLabel);CHKERRQ(ierr);
353   for (l = 0, c = cStart; l < numLeaves && c < cEnd; ++l, ++c) {
354     for (; c < leafLocal[l] && c < cEnd; ++c) {
355       ierr = DMLabelSetValue(vtkLabel, c, 1);CHKERRQ(ierr);
356     }
357     if (leafLocal[l] >= cEnd) break;
358     if (leafRemote[l].rank == rank) {
359       ierr = DMLabelSetValue(vtkLabel, c, 1);CHKERRQ(ierr);
360     } else {
361       ierr = DMLabelSetValue(ghostLabel, c, 2);CHKERRQ(ierr);
362     }
363   }
364   for (; c < cEnd; ++c) {
365     ierr = DMLabelSetValue(vtkLabel, c, 1);CHKERRQ(ierr);
366   }
367   if (0) {
368     ierr = PetscViewerASCIISynchronizedAllow(PETSC_VIEWER_STDOUT_WORLD, PETSC_TRUE);CHKERRQ(ierr);
369     ierr = DMLabelView(vtkLabel, PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
370     ierr = PetscViewerFlush(PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
371   }
372   ierr = DMPlexGetHeightStratum(dmNew, 1, &fStart, &fEnd);CHKERRQ(ierr);
373   for (f = fStart; f < fEnd; ++f) {
374     PetscInt numCells;
375 
376     ierr = DMPlexGetSupportSize(dmNew, f, &numCells);CHKERRQ(ierr);
377     if (numCells < 2) {
378       ierr = DMLabelSetValue(ghostLabel, f, 1);CHKERRQ(ierr);
379     } else {
380       const PetscInt *cells = NULL;
381       PetscInt        vA, vB;
382 
383       ierr = DMPlexGetSupport(dmNew, f, &cells);CHKERRQ(ierr);
384       ierr = DMLabelGetValue(vtkLabel, cells[0], &vA);CHKERRQ(ierr);
385       ierr = DMLabelGetValue(vtkLabel, cells[1], &vB);CHKERRQ(ierr);
386       if (!vA && !vB) {ierr = DMLabelSetValue(ghostLabel, f, 1);CHKERRQ(ierr);}
387     }
388   }
389   if (0) {
390     ierr = PetscViewerASCIISynchronizedAllow(PETSC_VIEWER_STDOUT_WORLD, PETSC_TRUE);CHKERRQ(ierr);
391     ierr = DMLabelView(ghostLabel, PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
392     ierr = PetscViewerFlush(PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
393   }
394   PetscFunctionReturn(0);
395 }
396 
397 #undef __FUNCT__
398 #define __FUNCT__ "DMPlexConstructGhostCells_Internal"
399 static PetscErrorCode DMPlexConstructGhostCells_Internal(DM dm, DMLabel label, PetscInt *numGhostCells, DM gdm)
400 {
401   IS              valueIS;
402   const PetscInt *values;
403   PetscInt       *depthShift;
404   PetscInt        depth = 0, numFS, fs, ghostCell, cEnd, c;
405   PetscErrorCode  ierr;
406 
407   PetscFunctionBegin;
408   /* Count ghost cells */
409   ierr = DMLabelGetValueIS(label, &valueIS);CHKERRQ(ierr);
410   ierr = ISGetLocalSize(valueIS, &numFS);CHKERRQ(ierr);
411   ierr = ISGetIndices(valueIS, &values);CHKERRQ(ierr);
412 
413   *numGhostCells = 0;
414   for (fs = 0; fs < numFS; ++fs) {
415     PetscInt numBdFaces;
416 
417     ierr = DMLabelGetStratumSize(label, values[fs], &numBdFaces);CHKERRQ(ierr);
418 
419     *numGhostCells += numBdFaces;
420   }
421   ierr = DMPlexGetDepth(dm, &depth);CHKERRQ(ierr);
422   ierr = PetscMalloc((depth+1) * sizeof(PetscInt), &depthShift);CHKERRQ(ierr);
423   ierr = PetscMemzero(depthShift, (depth+1) * sizeof(PetscInt));CHKERRQ(ierr);
424   if (depth >= 0) depthShift[depth] = *numGhostCells;
425   ierr = DMPlexShiftSizes_Internal(dm, depthShift, gdm);CHKERRQ(ierr);
426   /* Step 3: Set cone/support sizes for new points */
427   ierr = DMPlexGetHeightStratum(dm, 0, NULL, &cEnd);CHKERRQ(ierr);
428   for (c = cEnd; c < cEnd + *numGhostCells; ++c) {
429     ierr = DMPlexSetConeSize(gdm, c, 1);CHKERRQ(ierr);
430   }
431   for (fs = 0; fs < numFS; ++fs) {
432     IS              faceIS;
433     const PetscInt *faces;
434     PetscInt        numFaces, f;
435 
436     ierr = DMLabelGetStratumIS(label, values[fs], &faceIS);CHKERRQ(ierr);
437     ierr = ISGetLocalSize(faceIS, &numFaces);CHKERRQ(ierr);
438     ierr = ISGetIndices(faceIS, &faces);CHKERRQ(ierr);
439     for (f = 0; f < numFaces; ++f) {
440       PetscInt size;
441 
442       ierr = DMPlexGetSupportSize(dm, faces[f], &size);CHKERRQ(ierr);
443       if (size != 1) SETERRQ2(PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_WRONG, "DM has boundary face %d with %d support cells", faces[f], size);
444       ierr = DMPlexSetSupportSize(gdm, faces[f] + *numGhostCells, 2);CHKERRQ(ierr);
445     }
446     ierr = ISRestoreIndices(faceIS, &faces);CHKERRQ(ierr);
447     ierr = ISDestroy(&faceIS);CHKERRQ(ierr);
448   }
449   /* Step 4: Setup ghosted DM */
450   ierr = DMSetUp(gdm);CHKERRQ(ierr);
451   ierr = DMPlexShiftPoints_Internal(dm, depthShift, gdm);CHKERRQ(ierr);
452   /* Step 6: Set cones and supports for new points */
453   ghostCell = cEnd;
454   for (fs = 0; fs < numFS; ++fs) {
455     IS              faceIS;
456     const PetscInt *faces;
457     PetscInt        numFaces, f;
458 
459     ierr = DMLabelGetStratumIS(label, values[fs], &faceIS);CHKERRQ(ierr);
460     ierr = ISGetLocalSize(faceIS, &numFaces);CHKERRQ(ierr);
461     ierr = ISGetIndices(faceIS, &faces);CHKERRQ(ierr);
462     for (f = 0; f < numFaces; ++f, ++ghostCell) {
463       PetscInt newFace = faces[f] + *numGhostCells;
464 
465       ierr = DMPlexSetCone(gdm, ghostCell, &newFace);CHKERRQ(ierr);
466       ierr = DMPlexInsertSupport(gdm, newFace, 1, ghostCell);CHKERRQ(ierr);
467     }
468     ierr = ISRestoreIndices(faceIS, &faces);CHKERRQ(ierr);
469     ierr = ISDestroy(&faceIS);CHKERRQ(ierr);
470   }
471   ierr = ISRestoreIndices(valueIS, &values);CHKERRQ(ierr);
472   ierr = ISDestroy(&valueIS);CHKERRQ(ierr);
473   /* Step 7: Stratify */
474   ierr = DMPlexStratify(gdm);CHKERRQ(ierr);
475   ierr = DMPlexShiftCoordinates_Internal(dm, depthShift, gdm);CHKERRQ(ierr);
476   ierr = DMPlexShiftSF_Internal(dm, depthShift, gdm);CHKERRQ(ierr);
477   ierr = DMPlexShiftLabels_Internal(dm, depthShift, gdm);CHKERRQ(ierr);
478   ierr = PetscFree(depthShift);CHKERRQ(ierr);
479   PetscFunctionReturn(0);
480 }
481 
482 #undef __FUNCT__
483 #define __FUNCT__ "DMPlexConstructGhostCells"
484 /*@C
485   DMPlexConstructGhostCells - Construct ghost cells which connect to every boundary face
486 
487   Collective on dm
488 
489   Input Parameters:
490 + dm - The original DM
491 - labelName - The label specifying the boundary faces, or "Face Sets" if this is NULL
492 
493   Output Parameters:
494 + numGhostCells - The number of ghost cells added to the DM
495 - dmGhosted - The new DM
496 
497   Note: If no label exists of that name, one will be created marking all boundary faces
498 
499   Level: developer
500 
501 .seealso: DMCreate()
502 */
503 PetscErrorCode DMPlexConstructGhostCells(DM dm, const char labelName[], PetscInt *numGhostCells, DM *dmGhosted)
504 {
505   DM             gdm;
506   DMLabel        label;
507   const char    *name = labelName ? labelName : "Face Sets";
508   PetscInt       dim;
509   PetscErrorCode ierr;
510 
511   PetscFunctionBegin;
512   PetscValidHeaderSpecific(dm, DM_CLASSID, 1);
513   PetscValidPointer(numGhostCells, 3);
514   PetscValidPointer(dmGhosted, 4);
515   ierr = DMCreate(PetscObjectComm((PetscObject)dm), &gdm);CHKERRQ(ierr);
516   ierr = DMSetType(gdm, DMPLEX);CHKERRQ(ierr);
517   ierr = DMPlexGetDimension(dm, &dim);CHKERRQ(ierr);
518   ierr = DMPlexSetDimension(gdm, dim);CHKERRQ(ierr);
519   ierr = DMPlexGetLabel(dm, name, &label);CHKERRQ(ierr);
520   if (!label) {
521     /* Get label for boundary faces */
522     ierr = DMPlexCreateLabel(dm, name);CHKERRQ(ierr);
523     ierr = DMPlexGetLabel(dm, name, &label);CHKERRQ(ierr);
524     ierr = DMPlexMarkBoundaryFaces(dm, label);CHKERRQ(ierr);
525   }
526   ierr = DMPlexConstructGhostCells_Internal(dm, label, numGhostCells, gdm);CHKERRQ(ierr);
527   ierr = DMSetFromOptions(gdm);CHKERRQ(ierr);
528   *dmGhosted = gdm;
529   PetscFunctionReturn(0);
530 }
531 
532 #undef __FUNCT__
533 #define __FUNCT__ "DMPlexConstructCohesiveCells_Internal"
534 static PetscErrorCode DMPlexConstructCohesiveCells_Internal(DM dm, DMLabel label, DM sdm)
535 {
536   MPI_Comm        comm;
537   IS              valueIS, *pointIS;
538   const PetscInt *values, **splitPoints;
539   PetscSection    coordSection;
540   Vec             coordinates;
541   PetscScalar    *coords;
542   PetscInt       *depthShift, *depthOffset, *pMaxNew, *numSplitPoints, *coneNew, *supportNew;
543   PetscInt        shift = 100, depth = 0, dep, dim, d, numSP = 0, sp, maxConeSize, maxSupportSize, numLabels, p, v;
544   PetscErrorCode  ierr;
545 
546   PetscFunctionBegin;
547   ierr = PetscObjectGetComm((PetscObject)dm,&comm);CHKERRQ(ierr);
548   ierr = DMPlexGetDimension(dm, &dim);CHKERRQ(ierr);
549   /* Count split points and add cohesive cells */
550   if (label) {
551     ierr = DMLabelGetValueIS(label, &valueIS);CHKERRQ(ierr);
552     ierr = ISGetLocalSize(valueIS, &numSP);CHKERRQ(ierr);
553     ierr = ISGetIndices(valueIS, &values);CHKERRQ(ierr);
554   }
555   ierr = DMPlexGetDepth(dm, &depth);CHKERRQ(ierr);
556   ierr = DMPlexGetMaxSizes(dm, &maxConeSize, &maxSupportSize);CHKERRQ(ierr);
557   ierr = PetscMalloc5(depth+1,PetscInt,&depthShift,depth+1,PetscInt,&depthOffset,depth+1,PetscInt,&pMaxNew,maxConeSize*3,PetscInt,&coneNew,maxSupportSize,PetscInt,&supportNew);CHKERRQ(ierr);
558   ierr = PetscMalloc3(depth+1,IS,&pointIS,depth+1,PetscInt,&numSplitPoints,depth+1,const PetscInt*,&splitPoints);CHKERRQ(ierr);
559   ierr = PetscMemzero(depthShift, (depth+1) * sizeof(PetscInt));CHKERRQ(ierr);
560   for (d = 0; d <= depth; ++d) {
561     ierr              = DMPlexGetDepthStratum(dm, d, NULL, &pMaxNew[d]);CHKERRQ(ierr);
562     numSplitPoints[d] = 0;
563     splitPoints[d]    = NULL;
564     pointIS[d]        = NULL;
565   }
566   for (sp = 0; sp < numSP; ++sp) {
567     const PetscInt dep = values[sp];
568 
569     if ((dep < 0) || (dep > depth)) continue;
570     ierr = DMLabelGetStratumSize(label, dep, &depthShift[dep]);CHKERRQ(ierr);
571     ierr = DMLabelGetStratumIS(label, dep, &pointIS[dep]);CHKERRQ(ierr);
572     if (pointIS[dep]) {
573       ierr = ISGetLocalSize(pointIS[dep], &numSplitPoints[dep]);CHKERRQ(ierr);
574       ierr = ISGetIndices(pointIS[dep], &splitPoints[dep]);CHKERRQ(ierr);
575     }
576   }
577   if (depth >= 0) {
578     /* Calculate number of additional points */
579     depthShift[depth] = depthShift[depth-1]; /* There is a cohesive cell for every split face   */
580     depthShift[1]    += depthShift[0];       /* There is a cohesive edge for every split vertex */
581     /* Calculate hybrid bound for each dimension */
582     pMaxNew[0] += depthShift[depth];
583     if (depth > 1) pMaxNew[dim-1] += depthShift[depth] + depthShift[0];
584     if (depth > 2) pMaxNew[1]     += depthShift[depth] + depthShift[0] + depthShift[dim-1];
585 
586     /* Calculate point offset for each dimension */
587     depthOffset[depth] = 0;
588     depthOffset[0]     = depthOffset[depth] + depthShift[depth];
589     if (depth > 1) depthOffset[dim-1] = depthOffset[0]     + depthShift[0];
590     if (depth > 2) depthOffset[1]     = depthOffset[dim-1] + depthShift[dim-1];
591   }
592   ierr = DMPlexShiftSizes_Internal(dm, depthShift, sdm);CHKERRQ(ierr);
593   /* Step 3: Set cone/support sizes for new points */
594   for (dep = 0; dep <= depth; ++dep) {
595     for (p = 0; p < numSplitPoints[dep]; ++p) {
596       const PetscInt  oldp   = splitPoints[dep][p];
597       const PetscInt  newp   = depthOffset[dep] + oldp;
598       const PetscInt  splitp = pMaxNew[dep] + p;
599       const PetscInt *support;
600       PetscInt        coneSize, supportSize, q, e;
601 
602       ierr = DMPlexGetConeSize(dm, oldp, &coneSize);CHKERRQ(ierr);
603       ierr = DMPlexSetConeSize(sdm, splitp, coneSize);CHKERRQ(ierr);
604       ierr = DMPlexGetSupportSize(dm, oldp, &supportSize);CHKERRQ(ierr);
605       ierr = DMPlexSetSupportSize(sdm, splitp, supportSize);CHKERRQ(ierr);
606       if (dep == depth-1) {
607         const PetscInt ccell = pMaxNew[depth] + p;
608         /* Add cohesive cells, they are prisms */
609         ierr = DMPlexSetConeSize(sdm, ccell, 2 + coneSize);CHKERRQ(ierr);
610       } else if (dep == 0) {
611         const PetscInt cedge = pMaxNew[1] + (depthShift[1] - depthShift[0]) + p;
612 
613         ierr = DMPlexGetSupport(dm, oldp, &support);CHKERRQ(ierr);
614         /* Split old vertex: Edges in old split faces and new cohesive edge */
615         for (e = 0, q = 0; e < supportSize; ++e) {
616           PetscInt val;
617 
618           ierr = DMLabelGetValue(label, support[e], &val);CHKERRQ(ierr);
619           if ((val == 1) || (val == (shift + 1))) ++q;
620         }
621         ierr = DMPlexSetSupportSize(sdm, newp, q+1);CHKERRQ(ierr);
622         /* Split new vertex: Edges in new split faces and new cohesive edge */
623         for (e = 0, q = 0; e < supportSize; ++e) {
624           PetscInt val;
625 
626           ierr = DMLabelGetValue(label, support[e], &val);CHKERRQ(ierr);
627           if ((val == 1) || (val == -(shift + 1))) ++q;
628         }
629         ierr = DMPlexSetSupportSize(sdm, splitp, q+1);CHKERRQ(ierr);
630         /* Add cohesive edges */
631         ierr = DMPlexSetConeSize(sdm, cedge, 2);CHKERRQ(ierr);
632         /* Punt for now on support, you loop over closure, extract faces, check which ones are in the label */
633       } else if (dep == dim-2) {
634         ierr = DMPlexGetSupport(dm, oldp, &support);CHKERRQ(ierr);
635         /* Split old edge: Faces in positive side cells and old split faces */
636         for (e = 0, q = 0; e < supportSize; ++e) {
637           PetscInt val;
638 
639           ierr = DMLabelGetValue(label, support[e], &val);CHKERRQ(ierr);
640           if ((val == dim-1) || (val == (shift + dim-1))) ++q;
641         }
642         ierr = DMPlexSetSupportSize(sdm, newp, q);CHKERRQ(ierr);
643         /* Split new edge: Faces in negative side cells and new split faces */
644         for (e = 0, q = 0; e < supportSize; ++e) {
645           PetscInt val;
646 
647           ierr = DMLabelGetValue(label, support[e], &val);CHKERRQ(ierr);
648           if ((val == dim-1) || (val == -(shift + dim-1))) ++q;
649         }
650         ierr = DMPlexSetSupportSize(sdm, splitp, q);CHKERRQ(ierr);
651       }
652     }
653   }
654   /* Step 4: Setup split DM */
655   ierr = DMSetUp(sdm);CHKERRQ(ierr);
656   ierr = DMPlexShiftPoints_Internal(dm, depthShift, sdm);CHKERRQ(ierr);
657   /* Step 6: Set cones and supports for new points */
658   for (dep = 0; dep <= depth; ++dep) {
659     for (p = 0; p < numSplitPoints[dep]; ++p) {
660       const PetscInt  oldp   = splitPoints[dep][p];
661       const PetscInt  newp   = depthOffset[dep] + oldp;
662       const PetscInt  splitp = pMaxNew[dep] + p;
663       const PetscInt *cone, *support, *ornt;
664       PetscInt        coneSize, supportSize, q, v, e, s;
665 
666       ierr = DMPlexGetConeSize(dm, oldp, &coneSize);CHKERRQ(ierr);
667       ierr = DMPlexGetCone(dm, oldp, &cone);CHKERRQ(ierr);
668       ierr = DMPlexGetConeOrientation(dm, oldp, &ornt);CHKERRQ(ierr);
669       ierr = DMPlexGetSupportSize(dm, oldp, &supportSize);CHKERRQ(ierr);
670       ierr = DMPlexGetSupport(dm, oldp, &support);CHKERRQ(ierr);
671       if (dep == depth-1) {
672         const PetscInt  ccell = pMaxNew[depth] + p;
673         const PetscInt *supportF;
674 
675         /* Split face:       copy in old face to new face to start */
676         ierr = DMPlexGetSupport(sdm, newp,  &supportF);CHKERRQ(ierr);
677         ierr = DMPlexSetSupport(sdm, splitp, supportF);CHKERRQ(ierr);
678         /* Split old face:   old vertices/edges in cone so no change */
679         /* Split new face:   new vertices/edges in cone */
680         for (q = 0; q < coneSize; ++q) {
681           ierr = PetscFindInt(cone[q], numSplitPoints[dim-2], splitPoints[dim-2], &v);CHKERRQ(ierr);
682 
683           coneNew[2+q] = pMaxNew[dim-2] + v;
684         }
685         ierr = DMPlexSetCone(sdm, splitp, &coneNew[2]);CHKERRQ(ierr);
686         ierr = DMPlexSetConeOrientation(sdm, splitp, ornt);CHKERRQ(ierr);
687         /* Cohesive cell:    Old and new split face, then new cohesive edges */
688         coneNew[0] = newp;
689         coneNew[1] = splitp;
690         for (q = 0; q < coneSize; ++q) {
691           coneNew[2+q] = (pMaxNew[1] - pMaxNew[dim-2]) + (depthShift[1] - depthShift[0]) + coneNew[2+q];
692         }
693         ierr = DMPlexSetCone(sdm, ccell, coneNew);CHKERRQ(ierr);
694 
695 
696         for (s = 0; s < supportSize; ++s) {
697           PetscInt val;
698 
699           ierr = DMLabelGetValue(label, support[s], &val);CHKERRQ(ierr);
700           if (val < 0) {
701             /* Split old face:   Replace negative side cell with cohesive cell */
702             ierr = DMPlexInsertSupport(sdm, newp, s, ccell);CHKERRQ(ierr);
703           } else {
704             /* Split new face:   Replace positive side cell with cohesive cell */
705             ierr = DMPlexInsertSupport(sdm, splitp, s, ccell);CHKERRQ(ierr);
706           }
707         }
708       } else if (dep == 0) {
709         const PetscInt cedge = pMaxNew[1] + (depthShift[1] - depthShift[0]) + p;
710 
711         /* Split old vertex: Edges in old split faces and new cohesive edge */
712         for (e = 0, q = 0; e < supportSize; ++e) {
713           PetscInt val;
714 
715           ierr = DMLabelGetValue(label, support[e], &val);CHKERRQ(ierr);
716           if ((val == 1) || (val == (shift + 1))) {
717             supportNew[q++] = depthOffset[1] + support[e];
718           }
719         }
720         supportNew[q] = cedge;
721 
722         ierr = DMPlexSetSupport(sdm, newp, supportNew);CHKERRQ(ierr);
723         /* Split new vertex: Edges in new split faces and new cohesive edge */
724         for (e = 0, q = 0; e < supportSize; ++e) {
725           PetscInt val, edge;
726 
727           ierr = DMLabelGetValue(label, support[e], &val);CHKERRQ(ierr);
728           if (val == 1) {
729             ierr = PetscFindInt(support[e], numSplitPoints[1], splitPoints[1], &edge);CHKERRQ(ierr);
730             if (edge < 0) SETERRQ1(comm, PETSC_ERR_ARG_WRONG, "Edge %d is not a split edge", support[e]);
731             supportNew[q++] = pMaxNew[1] + edge;
732           } else if (val == -(shift + 1)) {
733             supportNew[q++] = depthOffset[1] + support[e];
734           }
735         }
736         supportNew[q] = cedge;
737         ierr          = DMPlexSetSupport(sdm, splitp, supportNew);CHKERRQ(ierr);
738         /* Cohesive edge:    Old and new split vertex, punting on support */
739         coneNew[0] = newp;
740         coneNew[1] = splitp;
741         ierr       = DMPlexSetCone(sdm, cedge, coneNew);CHKERRQ(ierr);
742       } else if (dep == dim-2) {
743         /* Split old edge:   old vertices in cone so no change */
744         /* Split new edge:   new vertices in cone */
745         for (q = 0; q < coneSize; ++q) {
746           ierr = PetscFindInt(cone[q], numSplitPoints[dim-3], splitPoints[dim-3], &v);CHKERRQ(ierr);
747 
748           coneNew[q] = pMaxNew[dim-3] + v;
749         }
750         ierr = DMPlexSetCone(sdm, splitp, coneNew);CHKERRQ(ierr);
751         /* Split old edge: Faces in positive side cells and old split faces */
752         for (e = 0, q = 0; e < supportSize; ++e) {
753           PetscInt val;
754 
755           ierr = DMLabelGetValue(label, support[e], &val);CHKERRQ(ierr);
756           if ((val == dim-1) || (val == (shift + dim-1))) {
757             supportNew[q++] = depthOffset[dim-1] + support[e];
758           }
759         }
760         ierr = DMPlexSetSupport(sdm, newp, supportNew);CHKERRQ(ierr);
761         /* Split new edge: Faces in negative side cells and new split faces */
762         for (e = 0, q = 0; e < supportSize; ++e) {
763           PetscInt val, face;
764 
765           ierr = DMLabelGetValue(label, support[e], &val);CHKERRQ(ierr);
766           if (val == dim-1) {
767             ierr = PetscFindInt(support[e], numSplitPoints[dim-1], splitPoints[dim-1], &face);CHKERRQ(ierr);
768             if (face < 0) SETERRQ1(comm, PETSC_ERR_ARG_WRONG, "Face %d is not a split face", support[e]);
769             supportNew[q++] = pMaxNew[dim-1] + face;
770           } else if (val == -(shift + dim-1)) {
771             supportNew[q++] = depthOffset[dim-1] + support[e];
772           }
773         }
774         ierr = DMPlexSetSupport(sdm, splitp, supportNew);CHKERRQ(ierr);
775       }
776     }
777   }
778   /* Step 6b: Replace split points in negative side cones */
779   for (sp = 0; sp < numSP; ++sp) {
780     PetscInt        dep = values[sp];
781     IS              pIS;
782     PetscInt        numPoints;
783     const PetscInt *points;
784 
785     if (dep >= 0) continue;
786     ierr = DMLabelGetStratumIS(label, dep, &pIS);CHKERRQ(ierr);
787     if (!pIS) continue;
788     dep  = -dep - shift;
789     ierr = ISGetLocalSize(pIS, &numPoints);CHKERRQ(ierr);
790     ierr = ISGetIndices(pIS, &points);CHKERRQ(ierr);
791     for (p = 0; p < numPoints; ++p) {
792       const PetscInt  oldp = points[p];
793       const PetscInt  newp = depthOffset[dep] + oldp;
794       const PetscInt *cone;
795       PetscInt        coneSize, c;
796       PetscBool       replaced = PETSC_FALSE;
797 
798       /* Negative edge: replace split vertex */
799       /* Negative cell: replace split face */
800       ierr = DMPlexGetConeSize(sdm, newp, &coneSize);CHKERRQ(ierr);
801       ierr = DMPlexGetCone(sdm, newp, &cone);CHKERRQ(ierr);
802       for (c = 0; c < coneSize; ++c) {
803         const PetscInt coldp = cone[c] - depthOffset[dep-1];
804         PetscInt       csplitp, cp, val;
805 
806         ierr = DMLabelGetValue(label, coldp, &val);CHKERRQ(ierr);
807         if (val == dep-1) {
808           ierr = PetscFindInt(coldp, numSplitPoints[dep-1], splitPoints[dep-1], &cp);CHKERRQ(ierr);
809           if (cp < 0) SETERRQ2(comm, PETSC_ERR_ARG_WRONG, "Point %d is not a split point of dimension %d", oldp, dep-1);
810           csplitp  = pMaxNew[dep-1] + cp;
811           ierr     = DMPlexInsertCone(sdm, newp, c, csplitp);CHKERRQ(ierr);
812           replaced = PETSC_TRUE;
813         }
814       }
815       if (!replaced) SETERRQ1(comm, PETSC_ERR_ARG_WRONG, "The cone of point %d does not contain split points", oldp);
816     }
817     ierr = ISRestoreIndices(pIS, &points);CHKERRQ(ierr);
818     ierr = ISDestroy(&pIS);CHKERRQ(ierr);
819   }
820   /* Step 7: Stratify */
821   ierr = DMPlexStratify(sdm);CHKERRQ(ierr);
822   /* Step 8: Coordinates */
823   ierr = DMPlexShiftCoordinates_Internal(dm, depthShift, sdm);CHKERRQ(ierr);
824   ierr = DMPlexGetCoordinateSection(sdm, &coordSection);CHKERRQ(ierr);
825   ierr = DMGetCoordinatesLocal(sdm, &coordinates);CHKERRQ(ierr);
826   ierr = VecGetArray(coordinates, &coords);CHKERRQ(ierr);
827   for (v = 0; v < (numSplitPoints ? numSplitPoints[0] : 0); ++v) {
828     const PetscInt newp   = depthOffset[0] + splitPoints[0][v];
829     const PetscInt splitp = pMaxNew[0] + v;
830     PetscInt       dof, off, soff, d;
831 
832     ierr = PetscSectionGetDof(coordSection, newp, &dof);CHKERRQ(ierr);
833     ierr = PetscSectionGetOffset(coordSection, newp, &off);CHKERRQ(ierr);
834     ierr = PetscSectionGetOffset(coordSection, splitp, &soff);CHKERRQ(ierr);
835     for (d = 0; d < dof; ++d) coords[soff+d] = coords[off+d];
836   }
837   ierr = VecRestoreArray(coordinates, &coords);CHKERRQ(ierr);
838   /* Step 9: SF, if I can figure this out we can split the mesh in parallel */
839   ierr = DMPlexShiftSF_Internal(dm, depthShift, sdm);CHKERRQ(ierr);
840   /* Step 10: Labels */
841   ierr = DMPlexShiftLabels_Internal(dm, depthShift, sdm);CHKERRQ(ierr);
842   ierr = DMPlexGetNumLabels(sdm, &numLabels);CHKERRQ(ierr);
843   for (dep = 0; dep <= depth; ++dep) {
844     for (p = 0; p < numSplitPoints[dep]; ++p) {
845       const PetscInt newp   = depthOffset[dep] + splitPoints[dep][p];
846       const PetscInt splitp = pMaxNew[dep] + p;
847       PetscInt       l;
848 
849       for (l = 0; l < numLabels; ++l) {
850         DMLabel     mlabel;
851         const char *lname;
852         PetscInt    val;
853 
854         ierr = DMPlexGetLabelName(sdm, l, &lname);CHKERRQ(ierr);
855         ierr = DMPlexGetLabel(sdm, lname, &mlabel);CHKERRQ(ierr);
856         ierr = DMLabelGetValue(mlabel, newp, &val);CHKERRQ(ierr);
857         if (val >= 0) {
858           ierr = DMLabelSetValue(mlabel, splitp, val);CHKERRQ(ierr);
859           if (dep == 0) {
860             const PetscInt cedge = pMaxNew[1] + (depthShift[1] - depthShift[0]) + p;
861             ierr = DMLabelSetValue(mlabel, cedge, val);CHKERRQ(ierr);
862           }
863         }
864       }
865     }
866   }
867   for (sp = 0; sp < numSP; ++sp) {
868     const PetscInt dep = values[sp];
869 
870     if ((dep < 0) || (dep > depth)) continue;
871     if (pointIS[dep]) {ierr = ISRestoreIndices(pointIS[dep], &splitPoints[dep]);CHKERRQ(ierr);}
872     ierr = ISDestroy(&pointIS[dep]);CHKERRQ(ierr);
873   }
874   if (label) {
875     ierr = ISRestoreIndices(valueIS, &values);CHKERRQ(ierr);
876     ierr = ISDestroy(&valueIS);CHKERRQ(ierr);
877   }
878   ierr = PetscFree5(depthShift, depthOffset, pMaxNew, coneNew, supportNew);CHKERRQ(ierr);
879   ierr = PetscFree3(pointIS, numSplitPoints, splitPoints);CHKERRQ(ierr);
880   PetscFunctionReturn(0);
881 }
882 
883 #undef __FUNCT__
884 #define __FUNCT__ "DMPlexConstructCohesiveCells"
885 /*@C
886   DMPlexConstructCohesiveCells - Construct cohesive cells which split the face along an internal interface
887 
888   Collective on dm
889 
890   Input Parameters:
891 + dm - The original DM
892 - labelName - The label specifying the boundary faces (this could be auto-generated)
893 
894   Output Parameters:
895 - dmSplit - The new DM
896 
897   Level: developer
898 
899 .seealso: DMCreate(), DMPlexLabelCohesiveComplete()
900 @*/
901 PetscErrorCode DMPlexConstructCohesiveCells(DM dm, DMLabel label, DM *dmSplit)
902 {
903   DM             sdm;
904   PetscInt       dim;
905   PetscErrorCode ierr;
906 
907   PetscFunctionBegin;
908   PetscValidHeaderSpecific(dm, DM_CLASSID, 1);
909   PetscValidPointer(dmSplit, 4);
910   ierr = DMCreate(PetscObjectComm((PetscObject)dm), &sdm);CHKERRQ(ierr);
911   ierr = DMSetType(sdm, DMPLEX);CHKERRQ(ierr);
912   ierr = DMPlexGetDimension(dm, &dim);CHKERRQ(ierr);
913   ierr = DMPlexSetDimension(sdm, dim);CHKERRQ(ierr);
914   switch (dim) {
915   case 2:
916   case 3:
917     ierr = DMPlexConstructCohesiveCells_Internal(dm, label, sdm);CHKERRQ(ierr);
918     break;
919   default:
920     SETERRQ1(PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_OUTOFRANGE, "Cannot construct cohesive cells for dimension %d", dim);
921   }
922   *dmSplit = sdm;
923   PetscFunctionReturn(0);
924 }
925 
926 #undef __FUNCT__
927 #define __FUNCT__ "DMPlexLabelCohesiveComplete"
928 /*@
929   DMPlexLabelCohesiveComplete - Starting with a label marking vertices on an internal surface, we add all other mesh pieces
930   to complete the surface
931 
932   Input Parameters:
933 + dm - The DM
934 - label - A DMLabel marking the surface vertices
935 
936   Output Parameter:
937 . label - A DMLabel marking all surface points
938 
939   Level: developer
940 
941 .seealso: DMPlexConstructCohesiveCells(), DMPlexLabelComplete()
942 @*/
943 PetscErrorCode DMPlexLabelCohesiveComplete(DM dm, DMLabel label)
944 {
945   IS              dimIS;
946   const PetscInt *points;
947   PetscInt        shift = 100, dim, dep, cStart, cEnd, numPoints, p, val;
948   PetscErrorCode  ierr;
949 
950   PetscFunctionBegin;
951   ierr = DMPlexGetDimension(dm, &dim);CHKERRQ(ierr);
952   /* Cell orientation for face gives the side of the fault */
953   ierr = DMLabelGetStratumIS(label, dim-1, &dimIS);CHKERRQ(ierr);
954   if (!dimIS) PetscFunctionReturn(0);
955   ierr = ISGetLocalSize(dimIS, &numPoints);CHKERRQ(ierr);
956   ierr = ISGetIndices(dimIS, &points);CHKERRQ(ierr);
957   for (p = 0; p < numPoints; ++p) {
958     const PetscInt *support;
959     PetscInt        supportSize, s;
960 
961     ierr = DMPlexGetSupportSize(dm, points[p], &supportSize);CHKERRQ(ierr);
962     if (supportSize != 2) SETERRQ2(PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_WRONG, "Split face %d has %d != 2 supports", points[p], supportSize);
963     ierr = DMPlexGetSupport(dm, points[p], &support);CHKERRQ(ierr);
964     for (s = 0; s < supportSize; ++s) {
965       const PetscInt *cone, *ornt;
966       PetscInt        coneSize, c;
967       PetscBool       pos = PETSC_TRUE;
968 
969       ierr = DMPlexGetConeSize(dm, support[s], &coneSize);CHKERRQ(ierr);
970       ierr = DMPlexGetCone(dm, support[s], &cone);CHKERRQ(ierr);
971       ierr = DMPlexGetConeOrientation(dm, support[s], &ornt);CHKERRQ(ierr);
972       for (c = 0; c < coneSize; ++c) {
973         if (cone[c] == points[p]) {
974           if (ornt[c] >= 0) {
975             ierr = DMLabelSetValue(label, support[s],   shift+dim);CHKERRQ(ierr);
976           } else {
977             ierr = DMLabelSetValue(label, support[s], -(shift+dim));CHKERRQ(ierr);
978             pos  = PETSC_FALSE;
979           }
980           break;
981         }
982       }
983       if (c == coneSize) SETERRQ1(PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_WRONG, "Cell split face %d support does not have it in the cone", points[p]);
984       /* Put faces touching the fault in the label */
985       for (c = 0; c < coneSize; ++c) {
986         const PetscInt point = cone[c];
987 
988         ierr = DMLabelGetValue(label, point, &val);CHKERRQ(ierr);
989         if (val == -1) {
990           PetscInt *closure = NULL;
991           PetscInt  closureSize, cl;
992 
993           ierr = DMPlexGetTransitiveClosure(dm, point, PETSC_TRUE, &closureSize, &closure);CHKERRQ(ierr);
994           for (cl = 0; cl < closureSize*2; cl += 2) {
995             const PetscInt clp = closure[cl];
996 
997             ierr = DMLabelGetValue(label, clp, &val);CHKERRQ(ierr);
998             if ((val >= 0) && (val < dim-1)) {
999               ierr = DMLabelSetValue(label, point, pos == PETSC_TRUE ? shift+dim-1 : -(shift+dim-1));CHKERRQ(ierr);
1000               break;
1001             }
1002           }
1003           ierr = DMPlexRestoreTransitiveClosure(dm, point, PETSC_TRUE, &closureSize, &closure);CHKERRQ(ierr);
1004         }
1005       }
1006     }
1007   }
1008   ierr = ISRestoreIndices(dimIS, &points);CHKERRQ(ierr);
1009   ierr = ISDestroy(&dimIS);CHKERRQ(ierr);
1010   /* Search for other cells/faces/edges connected to the fault by a vertex */
1011   ierr = DMPlexGetHeightStratum(dm, 0, &cStart, &cEnd);CHKERRQ(ierr);
1012   ierr = DMLabelGetStratumIS(label, 0, &dimIS);CHKERRQ(ierr);
1013   if (!dimIS) PetscFunctionReturn(0);
1014   ierr = ISGetLocalSize(dimIS, &numPoints);CHKERRQ(ierr);
1015   ierr = ISGetIndices(dimIS, &points);CHKERRQ(ierr);
1016   for (p = 0; p < numPoints; ++p) {
1017     PetscInt *star = NULL;
1018     PetscInt  starSize, s;
1019     PetscInt  again = 1;  /* 0: Finished 1: Keep iterating after a change 2: No change */
1020 
1021     /* First mark cells connected to the fault */
1022     ierr = DMPlexGetTransitiveClosure(dm, points[p], PETSC_FALSE, &starSize, &star);CHKERRQ(ierr);
1023     while (again) {
1024       if (again > 1) SETERRQ(PetscObjectComm((PetscObject)dm), PETSC_ERR_PLIB, "Could not classify all cells connected to the fault");
1025       again = 0;
1026       for (s = 0; s < starSize*2; s += 2) {
1027         const PetscInt  point = star[s];
1028         const PetscInt *cone;
1029         PetscInt        coneSize, c;
1030 
1031         if ((point < cStart) || (point >= cEnd)) continue;
1032         ierr = DMLabelGetValue(label, point, &val);CHKERRQ(ierr);
1033         if (val != -1) continue;
1034         again = 2;
1035         ierr  = DMPlexGetConeSize(dm, point, &coneSize);CHKERRQ(ierr);
1036         ierr  = DMPlexGetCone(dm, point, &cone);CHKERRQ(ierr);
1037         for (c = 0; c < coneSize; ++c) {
1038           ierr = DMLabelGetValue(label, cone[c], &val);CHKERRQ(ierr);
1039           if (val != -1) {
1040             if (abs(val) < shift) SETERRQ3(PetscObjectComm((PetscObject)dm), PETSC_ERR_PLIB, "Face %d on cell %d has an invalid label %d", cone[c], point, val);
1041             if (val > 0) {
1042               ierr = DMLabelSetValue(label, point,   shift+dim);CHKERRQ(ierr);
1043             } else {
1044               ierr = DMLabelSetValue(label, point, -(shift+dim));CHKERRQ(ierr);
1045             }
1046             again = 1;
1047             break;
1048           }
1049         }
1050       }
1051     }
1052     /* Classify the rest by cell membership */
1053     for (s = 0; s < starSize*2; s += 2) {
1054       const PetscInt point = star[s];
1055 
1056       ierr = DMLabelGetValue(label, point, &val);CHKERRQ(ierr);
1057       if (val == -1) {
1058         PetscInt  *sstar = NULL;
1059         PetscInt   sstarSize, ss;
1060         PetscBool  marked = PETSC_FALSE;
1061 
1062         ierr = DMPlexGetTransitiveClosure(dm, point, PETSC_FALSE, &sstarSize, &sstar);CHKERRQ(ierr);
1063         for (ss = 0; ss < sstarSize*2; ss += 2) {
1064           const PetscInt spoint = sstar[ss];
1065 
1066           if ((spoint < cStart) || (spoint >= cEnd)) continue;
1067           ierr = DMLabelGetValue(label, spoint, &val);CHKERRQ(ierr);
1068           if (val == -1) SETERRQ2(PetscObjectComm((PetscObject)dm), PETSC_ERR_PLIB, "Cell %d in star of %d does not have a valid label", spoint, point);
1069           ierr = DMPlexGetLabelValue(dm, "depth", point, &dep);CHKERRQ(ierr);
1070           if (val > 0) {
1071             ierr = DMLabelSetValue(label, point,   shift+dep);CHKERRQ(ierr);
1072           } else {
1073             ierr = DMLabelSetValue(label, point, -(shift+dep));CHKERRQ(ierr);
1074           }
1075           marked = PETSC_TRUE;
1076           break;
1077         }
1078         ierr = DMPlexRestoreTransitiveClosure(dm, point, PETSC_FALSE, &sstarSize, &sstar);CHKERRQ(ierr);
1079         if (!marked) SETERRQ1(PetscObjectComm((PetscObject)dm), PETSC_ERR_PLIB, "Point %d could not be classified", point);
1080       }
1081     }
1082     ierr = DMPlexRestoreTransitiveClosure(dm, points[p], PETSC_FALSE, &starSize, &star);CHKERRQ(ierr);
1083   }
1084   ierr = ISRestoreIndices(dimIS, &points);CHKERRQ(ierr);
1085   ierr = ISDestroy(&dimIS);CHKERRQ(ierr);
1086   PetscFunctionReturn(0);
1087 }
1088 
1089 #undef __FUNCT__
1090 #define __FUNCT__ "DMPlexMarkSubmesh_Uninterpolated"
1091 /* Here we need the explicit assumption that:
1092 
1093      For any marked cell, the marked vertices constitute a single face
1094 */
1095 static PetscErrorCode DMPlexMarkSubmesh_Uninterpolated(DM dm, DMLabel vertexLabel, DMLabel subpointMap, PetscInt *numFaces, PetscInt *nFV, DM subdm)
1096 {
1097   IS               subvertexIS;
1098   const PetscInt  *subvertices;
1099   PetscInt        *pStart, *pEnd, *pMax;
1100   PetscInt         depth, dim, d, numSubVerticesInitial = 0, v;
1101   PetscErrorCode   ierr;
1102 
1103   PetscFunctionBegin;
1104   *numFaces = 0;
1105   *nFV      = 0;
1106   ierr = DMPlexGetDepth(dm, &depth);CHKERRQ(ierr);
1107   ierr = DMPlexGetDimension(dm, &dim);CHKERRQ(ierr);
1108   ierr = PetscMalloc3(dim+1,PetscInt,&pStart,dim+1,PetscInt,&pEnd,dim+1,PetscInt,&pMax);CHKERRQ(ierr);
1109   ierr = DMPlexGetHybridBounds(dm, &pMax[depth], depth>1 ? &pMax[depth-1] : NULL, depth > 2 ? &pMax[1] : NULL, &pMax[0]);CHKERRQ(ierr);
1110   for (d = 0; d <= depth; ++d) {
1111     ierr = DMPlexGetDepthStratum(dm, d, &pStart[d], &pEnd[d]);CHKERRQ(ierr);
1112     if (pMax[d] >= 0) pEnd[d] = PetscMin(pEnd[d], pMax[d]);
1113   }
1114   /* Loop over initial vertices and mark all faces in the collective star() */
1115   ierr = DMLabelGetStratumIS(vertexLabel, 1, &subvertexIS);CHKERRQ(ierr);
1116   if (subvertexIS) {
1117     ierr = ISGetSize(subvertexIS, &numSubVerticesInitial);CHKERRQ(ierr);
1118     ierr = ISGetIndices(subvertexIS, &subvertices);CHKERRQ(ierr);
1119   }
1120   for (v = 0; v < numSubVerticesInitial; ++v) {
1121     const PetscInt vertex = subvertices[v];
1122     PetscInt      *star   = NULL;
1123     PetscInt       starSize, s, numCells = 0, c;
1124 
1125     ierr = DMPlexGetTransitiveClosure(dm, vertex, PETSC_FALSE, &starSize, &star);CHKERRQ(ierr);
1126     for (s = 0; s < starSize*2; s += 2) {
1127       const PetscInt point = star[s];
1128       if ((point >= pStart[depth]) && (point < pEnd[depth])) star[numCells++] = point;
1129     }
1130     for (c = 0; c < numCells; ++c) {
1131       const PetscInt cell    = star[c];
1132       PetscInt      *closure = NULL;
1133       PetscInt       closureSize, cl;
1134       PetscInt       cellLoc, numCorners = 0, faceSize = 0;
1135 
1136       ierr = DMLabelGetValue(subpointMap, cell, &cellLoc);CHKERRQ(ierr);
1137       if (cellLoc == 2) continue;
1138       if (cellLoc >= 0) SETERRQ2(PetscObjectComm((PetscObject)dm), PETSC_ERR_PLIB, "Cell %d has dimension %d in the surface label", cell, cellLoc);
1139       ierr = DMPlexGetTransitiveClosure(dm, cell, PETSC_TRUE, &closureSize, &closure);CHKERRQ(ierr);
1140       for (cl = 0; cl < closureSize*2; cl += 2) {
1141         const PetscInt point = closure[cl];
1142         PetscInt       vertexLoc;
1143 
1144         if ((point >= pStart[0]) && (point < pEnd[0])) {
1145           ++numCorners;
1146           ierr = DMLabelGetValue(vertexLabel, point, &vertexLoc);CHKERRQ(ierr);
1147           if (vertexLoc >= 0) closure[faceSize++] = point;
1148         }
1149       }
1150       if (!(*nFV)) {ierr = DMPlexGetNumFaceVertices(dm, dim, numCorners, nFV);CHKERRQ(ierr);}
1151       if (faceSize > *nFV) SETERRQ1(PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_WRONG, "Invalid submesh: Too many vertices %d of an element on the surface", faceSize);
1152       if (faceSize == *nFV) {
1153         ++(*numFaces);
1154         for (cl = 0; cl < faceSize; ++cl) {
1155           ierr = DMLabelSetValue(subpointMap, closure[cl], 0);CHKERRQ(ierr);
1156         }
1157         ierr = DMLabelSetValue(subpointMap, cell, 2);CHKERRQ(ierr);
1158       }
1159       ierr = DMPlexRestoreTransitiveClosure(dm, cell, PETSC_TRUE, &closureSize, &closure);CHKERRQ(ierr);
1160     }
1161     ierr = DMPlexRestoreTransitiveClosure(dm, vertex, PETSC_FALSE, &starSize, &star);CHKERRQ(ierr);
1162   }
1163   if (subvertexIS) {
1164     ierr = ISRestoreIndices(subvertexIS, &subvertices);CHKERRQ(ierr);
1165   }
1166   ierr = ISDestroy(&subvertexIS);CHKERRQ(ierr);
1167   ierr = PetscFree3(pStart,pEnd,pMax);CHKERRQ(ierr);
1168   PetscFunctionReturn(0);
1169 }
1170 
1171 #undef __FUNCT__
1172 #define __FUNCT__ "DMPlexMarkSubmesh_Interpolated"
1173 static PetscErrorCode DMPlexMarkSubmesh_Interpolated(DM dm, DMLabel vertexLabel, DMLabel subpointMap, DM subdm)
1174 {
1175   IS               subvertexIS;
1176   const PetscInt  *subvertices;
1177   PetscInt        *pStart, *pEnd, *pMax;
1178   PetscInt         dim, d, numSubVerticesInitial = 0, v;
1179   PetscErrorCode   ierr;
1180 
1181   PetscFunctionBegin;
1182   ierr = DMPlexGetDimension(dm, &dim);CHKERRQ(ierr);
1183   ierr = PetscMalloc3(dim+1,PetscInt,&pStart,dim+1,PetscInt,&pEnd,dim+1,PetscInt,&pMax);CHKERRQ(ierr);
1184   ierr = DMPlexGetHybridBounds(dm, &pMax[dim], dim>1 ? &pMax[dim-1] : NULL, dim > 2 ? &pMax[1] : NULL, &pMax[0]);CHKERRQ(ierr);
1185   for (d = 0; d <= dim; ++d) {
1186     ierr = DMPlexGetDepthStratum(dm, d, &pStart[d], &pEnd[d]);CHKERRQ(ierr);
1187     if (pMax[d] >= 0) pEnd[d] = PetscMin(pEnd[d], pMax[d]);
1188   }
1189   /* Loop over initial vertices and mark all faces in the collective star() */
1190   ierr = DMLabelGetStratumIS(vertexLabel, 1, &subvertexIS);CHKERRQ(ierr);
1191   if (subvertexIS) {
1192     ierr = ISGetSize(subvertexIS, &numSubVerticesInitial);CHKERRQ(ierr);
1193     ierr = ISGetIndices(subvertexIS, &subvertices);CHKERRQ(ierr);
1194   }
1195   for (v = 0; v < numSubVerticesInitial; ++v) {
1196     const PetscInt vertex = subvertices[v];
1197     PetscInt      *star   = NULL;
1198     PetscInt       starSize, s, numFaces = 0, f;
1199 
1200     ierr = DMPlexGetTransitiveClosure(dm, vertex, PETSC_FALSE, &starSize, &star);CHKERRQ(ierr);
1201     for (s = 0; s < starSize*2; s += 2) {
1202       const PetscInt point = star[s];
1203       if ((point >= pStart[dim-1]) && (point < pEnd[dim-1])) star[numFaces++] = point;
1204     }
1205     for (f = 0; f < numFaces; ++f) {
1206       const PetscInt face    = star[f];
1207       PetscInt      *closure = NULL;
1208       PetscInt       closureSize, c;
1209       PetscInt       faceLoc;
1210 
1211       ierr = DMLabelGetValue(subpointMap, face, &faceLoc);CHKERRQ(ierr);
1212       if (faceLoc == dim-1) continue;
1213       if (faceLoc >= 0) SETERRQ2(PetscObjectComm((PetscObject)dm), PETSC_ERR_PLIB, "Face %d has dimension %d in the surface label", face, faceLoc);
1214       ierr = DMPlexGetTransitiveClosure(dm, face, PETSC_TRUE, &closureSize, &closure);CHKERRQ(ierr);
1215       for (c = 0; c < closureSize*2; c += 2) {
1216         const PetscInt point = closure[c];
1217         PetscInt       vertexLoc;
1218 
1219         if ((point >= pStart[0]) && (point < pEnd[0])) {
1220           ierr = DMLabelGetValue(vertexLabel, point, &vertexLoc);CHKERRQ(ierr);
1221           if (vertexLoc < 0) break;
1222         }
1223       }
1224       if (c == closureSize*2) {
1225         const PetscInt *support;
1226         PetscInt        supportSize, s;
1227 
1228         for (c = 0; c < closureSize*2; c += 2) {
1229           const PetscInt point = closure[c];
1230 
1231           for (d = 0; d < dim; ++d) {
1232             if ((point >= pStart[d]) && (point < pEnd[d])) {
1233               ierr = DMLabelSetValue(subpointMap, point, d);CHKERRQ(ierr);
1234               break;
1235             }
1236           }
1237         }
1238         ierr = DMPlexGetSupportSize(dm, face, &supportSize);CHKERRQ(ierr);
1239         ierr = DMPlexGetSupport(dm, face, &support);CHKERRQ(ierr);
1240         for (s = 0; s < supportSize; ++s) {
1241           ierr = DMLabelSetValue(subpointMap, support[s], dim);CHKERRQ(ierr);
1242         }
1243       }
1244       ierr = DMPlexRestoreTransitiveClosure(dm, face, PETSC_TRUE, &closureSize, &closure);CHKERRQ(ierr);
1245     }
1246     ierr = DMPlexRestoreTransitiveClosure(dm, vertex, PETSC_FALSE, &starSize, &star);CHKERRQ(ierr);
1247   }
1248   if (subvertexIS) {
1249     ierr = ISRestoreIndices(subvertexIS, &subvertices);CHKERRQ(ierr);
1250   }
1251   ierr = ISDestroy(&subvertexIS);CHKERRQ(ierr);
1252   ierr = PetscFree3(pStart,pEnd,pMax);CHKERRQ(ierr);
1253   PetscFunctionReturn(0);
1254 }
1255 
1256 #undef __FUNCT__
1257 #define __FUNCT__ "DMPlexGetFaceOrientation"
1258 PetscErrorCode DMPlexGetFaceOrientation(DM dm, PetscInt cell, PetscInt numCorners, PetscInt indices[], PetscInt oppositeVertex, PetscInt origVertices[], PetscInt faceVertices[], PetscBool *posOriented)
1259 {
1260   MPI_Comm       comm;
1261   PetscBool      posOrient = PETSC_FALSE;
1262   const PetscInt debug     = 0;
1263   PetscInt       cellDim, faceSize, f;
1264   PetscErrorCode ierr;
1265 
1266   PetscFunctionBegin;
1267   ierr = PetscObjectGetComm((PetscObject)dm,&comm);CHKERRQ(ierr);
1268   ierr = DMPlexGetDimension(dm, &cellDim);CHKERRQ(ierr);
1269   if (debug) {PetscPrintf(comm, "cellDim: %d numCorners: %d\n", cellDim, numCorners);CHKERRQ(ierr);}
1270 
1271   if (cellDim == numCorners-1) {
1272     /* Simplices */
1273     faceSize  = numCorners-1;
1274     posOrient = !(oppositeVertex%2) ? PETSC_TRUE : PETSC_FALSE;
1275   } else if (cellDim == 1 && numCorners == 3) {
1276     /* Quadratic line */
1277     faceSize  = 1;
1278     posOrient = PETSC_TRUE;
1279   } else if (cellDim == 2 && numCorners == 4) {
1280     /* Quads */
1281     faceSize = 2;
1282     if ((indices[1] > indices[0]) && (indices[1] - indices[0] == 1)) {
1283       posOrient = PETSC_TRUE;
1284     } else if ((indices[0] == 3) && (indices[1] == 0)) {
1285       posOrient = PETSC_TRUE;
1286     } else {
1287       if (((indices[0] > indices[1]) && (indices[0] - indices[1] == 1)) || ((indices[0] == 0) && (indices[1] == 3))) {
1288         posOrient = PETSC_FALSE;
1289       } else SETERRQ(comm, PETSC_ERR_ARG_WRONG, "Invalid quad crossedge");
1290     }
1291   } else if (cellDim == 2 && numCorners == 6) {
1292     /* Quadratic triangle (I hate this) */
1293     /* Edges are determined by the first 2 vertices (corners of edges) */
1294     const PetscInt faceSizeTri = 3;
1295     PetscInt       sortedIndices[3], i, iFace;
1296     PetscBool      found                    = PETSC_FALSE;
1297     PetscInt       faceVerticesTriSorted[9] = {
1298       0, 3,  4, /* bottom */
1299       1, 4,  5, /* right */
1300       2, 3,  5, /* left */
1301     };
1302     PetscInt       faceVerticesTri[9] = {
1303       0, 3,  4, /* bottom */
1304       1, 4,  5, /* right */
1305       2, 5,  3, /* left */
1306     };
1307 
1308     faceSize = faceSizeTri;
1309     for (i = 0; i < faceSizeTri; ++i) sortedIndices[i] = indices[i];
1310     ierr = PetscSortInt(faceSizeTri, sortedIndices);CHKERRQ(ierr);
1311     for (iFace = 0; iFace < 3; ++iFace) {
1312       const PetscInt ii = iFace*faceSizeTri;
1313       PetscInt       fVertex, cVertex;
1314 
1315       if ((sortedIndices[0] == faceVerticesTriSorted[ii+0]) &&
1316           (sortedIndices[1] == faceVerticesTriSorted[ii+1])) {
1317         for (fVertex = 0; fVertex < faceSizeTri; ++fVertex) {
1318           for (cVertex = 0; cVertex < faceSizeTri; ++cVertex) {
1319             if (indices[cVertex] == faceVerticesTri[ii+fVertex]) {
1320               faceVertices[fVertex] = origVertices[cVertex];
1321               break;
1322             }
1323           }
1324         }
1325         found = PETSC_TRUE;
1326         break;
1327       }
1328     }
1329     if (!found) SETERRQ(comm, PETSC_ERR_ARG_WRONG, "Invalid tri crossface");
1330     if (posOriented) *posOriented = PETSC_TRUE;
1331     PetscFunctionReturn(0);
1332   } else if (cellDim == 2 && numCorners == 9) {
1333     /* Quadratic quad (I hate this) */
1334     /* Edges are determined by the first 2 vertices (corners of edges) */
1335     const PetscInt faceSizeQuad = 3;
1336     PetscInt       sortedIndices[3], i, iFace;
1337     PetscBool      found                      = PETSC_FALSE;
1338     PetscInt       faceVerticesQuadSorted[12] = {
1339       0, 1,  4, /* bottom */
1340       1, 2,  5, /* right */
1341       2, 3,  6, /* top */
1342       0, 3,  7, /* left */
1343     };
1344     PetscInt       faceVerticesQuad[12] = {
1345       0, 1,  4, /* bottom */
1346       1, 2,  5, /* right */
1347       2, 3,  6, /* top */
1348       3, 0,  7, /* left */
1349     };
1350 
1351     faceSize = faceSizeQuad;
1352     for (i = 0; i < faceSizeQuad; ++i) sortedIndices[i] = indices[i];
1353     ierr = PetscSortInt(faceSizeQuad, sortedIndices);CHKERRQ(ierr);
1354     for (iFace = 0; iFace < 4; ++iFace) {
1355       const PetscInt ii = iFace*faceSizeQuad;
1356       PetscInt       fVertex, cVertex;
1357 
1358       if ((sortedIndices[0] == faceVerticesQuadSorted[ii+0]) &&
1359           (sortedIndices[1] == faceVerticesQuadSorted[ii+1])) {
1360         for (fVertex = 0; fVertex < faceSizeQuad; ++fVertex) {
1361           for (cVertex = 0; cVertex < faceSizeQuad; ++cVertex) {
1362             if (indices[cVertex] == faceVerticesQuad[ii+fVertex]) {
1363               faceVertices[fVertex] = origVertices[cVertex];
1364               break;
1365             }
1366           }
1367         }
1368         found = PETSC_TRUE;
1369         break;
1370       }
1371     }
1372     if (!found) SETERRQ(comm, PETSC_ERR_ARG_WRONG, "Invalid quad crossface");
1373     if (posOriented) *posOriented = PETSC_TRUE;
1374     PetscFunctionReturn(0);
1375   } else if (cellDim == 3 && numCorners == 8) {
1376     /* Hexes
1377        A hex is two oriented quads with the normal of the first
1378        pointing up at the second.
1379 
1380           7---6
1381          /|  /|
1382         4---5 |
1383         | 3-|-2
1384         |/  |/
1385         0---1
1386 
1387         Faces are determined by the first 4 vertices (corners of faces) */
1388     const PetscInt faceSizeHex = 4;
1389     PetscInt       sortedIndices[4], i, iFace;
1390     PetscBool      found                     = PETSC_FALSE;
1391     PetscInt       faceVerticesHexSorted[24] = {
1392       0, 1, 2, 3,  /* bottom */
1393       4, 5, 6, 7,  /* top */
1394       0, 1, 4, 5,  /* front */
1395       1, 2, 5, 6,  /* right */
1396       2, 3, 6, 7,  /* back */
1397       0, 3, 4, 7,  /* left */
1398     };
1399     PetscInt       faceVerticesHex[24] = {
1400       3, 2, 1, 0,  /* bottom */
1401       4, 5, 6, 7,  /* top */
1402       0, 1, 5, 4,  /* front */
1403       1, 2, 6, 5,  /* right */
1404       2, 3, 7, 6,  /* back */
1405       3, 0, 4, 7,  /* left */
1406     };
1407 
1408     faceSize = faceSizeHex;
1409     for (i = 0; i < faceSizeHex; ++i) sortedIndices[i] = indices[i];
1410     ierr = PetscSortInt(faceSizeHex, sortedIndices);CHKERRQ(ierr);
1411     for (iFace = 0; iFace < 6; ++iFace) {
1412       const PetscInt ii = iFace*faceSizeHex;
1413       PetscInt       fVertex, cVertex;
1414 
1415       if ((sortedIndices[0] == faceVerticesHexSorted[ii+0]) &&
1416           (sortedIndices[1] == faceVerticesHexSorted[ii+1]) &&
1417           (sortedIndices[2] == faceVerticesHexSorted[ii+2]) &&
1418           (sortedIndices[3] == faceVerticesHexSorted[ii+3])) {
1419         for (fVertex = 0; fVertex < faceSizeHex; ++fVertex) {
1420           for (cVertex = 0; cVertex < faceSizeHex; ++cVertex) {
1421             if (indices[cVertex] == faceVerticesHex[ii+fVertex]) {
1422               faceVertices[fVertex] = origVertices[cVertex];
1423               break;
1424             }
1425           }
1426         }
1427         found = PETSC_TRUE;
1428         break;
1429       }
1430     }
1431     if (!found) SETERRQ(comm, PETSC_ERR_ARG_WRONG, "Invalid hex crossface");
1432     if (posOriented) *posOriented = PETSC_TRUE;
1433     PetscFunctionReturn(0);
1434   } else if (cellDim == 3 && numCorners == 10) {
1435     /* Quadratic tet */
1436     /* Faces are determined by the first 3 vertices (corners of faces) */
1437     const PetscInt faceSizeTet = 6;
1438     PetscInt       sortedIndices[6], i, iFace;
1439     PetscBool      found                     = PETSC_FALSE;
1440     PetscInt       faceVerticesTetSorted[24] = {
1441       0, 1, 2,  6, 7, 8, /* bottom */
1442       0, 3, 4,  6, 7, 9,  /* front */
1443       1, 4, 5,  7, 8, 9,  /* right */
1444       2, 3, 5,  6, 8, 9,  /* left */
1445     };
1446     PetscInt       faceVerticesTet[24] = {
1447       0, 1, 2,  6, 7, 8, /* bottom */
1448       0, 4, 3,  6, 7, 9,  /* front */
1449       1, 5, 4,  7, 8, 9,  /* right */
1450       2, 3, 5,  8, 6, 9,  /* left */
1451     };
1452 
1453     faceSize = faceSizeTet;
1454     for (i = 0; i < faceSizeTet; ++i) sortedIndices[i] = indices[i];
1455     ierr = PetscSortInt(faceSizeTet, sortedIndices);CHKERRQ(ierr);
1456     for (iFace=0; iFace < 4; ++iFace) {
1457       const PetscInt ii = iFace*faceSizeTet;
1458       PetscInt       fVertex, cVertex;
1459 
1460       if ((sortedIndices[0] == faceVerticesTetSorted[ii+0]) &&
1461           (sortedIndices[1] == faceVerticesTetSorted[ii+1]) &&
1462           (sortedIndices[2] == faceVerticesTetSorted[ii+2]) &&
1463           (sortedIndices[3] == faceVerticesTetSorted[ii+3])) {
1464         for (fVertex = 0; fVertex < faceSizeTet; ++fVertex) {
1465           for (cVertex = 0; cVertex < faceSizeTet; ++cVertex) {
1466             if (indices[cVertex] == faceVerticesTet[ii+fVertex]) {
1467               faceVertices[fVertex] = origVertices[cVertex];
1468               break;
1469             }
1470           }
1471         }
1472         found = PETSC_TRUE;
1473         break;
1474       }
1475     }
1476     if (!found) SETERRQ(comm, PETSC_ERR_ARG_WRONG, "Invalid tet crossface");
1477     if (posOriented) *posOriented = PETSC_TRUE;
1478     PetscFunctionReturn(0);
1479   } else if (cellDim == 3 && numCorners == 27) {
1480     /* Quadratic hexes (I hate this)
1481        A hex is two oriented quads with the normal of the first
1482        pointing up at the second.
1483 
1484          7---6
1485         /|  /|
1486        4---5 |
1487        | 3-|-2
1488        |/  |/
1489        0---1
1490 
1491        Faces are determined by the first 4 vertices (corners of faces) */
1492     const PetscInt faceSizeQuadHex = 9;
1493     PetscInt       sortedIndices[9], i, iFace;
1494     PetscBool      found                         = PETSC_FALSE;
1495     PetscInt       faceVerticesQuadHexSorted[54] = {
1496       0, 1, 2, 3,  8, 9, 10, 11,  24, /* bottom */
1497       4, 5, 6, 7,  12, 13, 14, 15,  25, /* top */
1498       0, 1, 4, 5,  8, 12, 16, 17,  22, /* front */
1499       1, 2, 5, 6,  9, 13, 17, 18,  21, /* right */
1500       2, 3, 6, 7,  10, 14, 18, 19,  23, /* back */
1501       0, 3, 4, 7,  11, 15, 16, 19,  20, /* left */
1502     };
1503     PetscInt       faceVerticesQuadHex[54] = {
1504       3, 2, 1, 0,  10, 9, 8, 11,  24, /* bottom */
1505       4, 5, 6, 7,  12, 13, 14, 15,  25, /* top */
1506       0, 1, 5, 4,  8, 17, 12, 16,  22, /* front */
1507       1, 2, 6, 5,  9, 18, 13, 17,  21, /* right */
1508       2, 3, 7, 6,  10, 19, 14, 18,  23, /* back */
1509       3, 0, 4, 7,  11, 16, 15, 19,  20 /* left */
1510     };
1511 
1512     faceSize = faceSizeQuadHex;
1513     for (i = 0; i < faceSizeQuadHex; ++i) sortedIndices[i] = indices[i];
1514     ierr = PetscSortInt(faceSizeQuadHex, sortedIndices);CHKERRQ(ierr);
1515     for (iFace = 0; iFace < 6; ++iFace) {
1516       const PetscInt ii = iFace*faceSizeQuadHex;
1517       PetscInt       fVertex, cVertex;
1518 
1519       if ((sortedIndices[0] == faceVerticesQuadHexSorted[ii+0]) &&
1520           (sortedIndices[1] == faceVerticesQuadHexSorted[ii+1]) &&
1521           (sortedIndices[2] == faceVerticesQuadHexSorted[ii+2]) &&
1522           (sortedIndices[3] == faceVerticesQuadHexSorted[ii+3])) {
1523         for (fVertex = 0; fVertex < faceSizeQuadHex; ++fVertex) {
1524           for (cVertex = 0; cVertex < faceSizeQuadHex; ++cVertex) {
1525             if (indices[cVertex] == faceVerticesQuadHex[ii+fVertex]) {
1526               faceVertices[fVertex] = origVertices[cVertex];
1527               break;
1528             }
1529           }
1530         }
1531         found = PETSC_TRUE;
1532         break;
1533       }
1534     }
1535     if (!found) SETERRQ(comm, PETSC_ERR_ARG_WRONG, "Invalid hex crossface");
1536     if (posOriented) *posOriented = PETSC_TRUE;
1537     PetscFunctionReturn(0);
1538   } else SETERRQ(comm, PETSC_ERR_ARG_WRONG, "Unknown cell type for faceOrientation().");
1539   if (!posOrient) {
1540     if (debug) {ierr = PetscPrintf(comm, "  Reversing initial face orientation\n");CHKERRQ(ierr);}
1541     for (f = 0; f < faceSize; ++f) faceVertices[f] = origVertices[faceSize-1 - f];
1542   } else {
1543     if (debug) {ierr = PetscPrintf(comm, "  Keeping initial face orientation\n");CHKERRQ(ierr);}
1544     for (f = 0; f < faceSize; ++f) faceVertices[f] = origVertices[f];
1545   }
1546   if (posOriented) *posOriented = posOrient;
1547   PetscFunctionReturn(0);
1548 }
1549 
1550 #undef __FUNCT__
1551 #define __FUNCT__ "DMPlexGetOrientedFace"
1552 /*
1553     Given a cell and a face, as a set of vertices,
1554       return the oriented face, as a set of vertices, in faceVertices
1555     The orientation is such that the face normal points out of the cell
1556 */
1557 PetscErrorCode DMPlexGetOrientedFace(DM dm, PetscInt cell, PetscInt faceSize, const PetscInt face[], PetscInt numCorners, PetscInt indices[], PetscInt origVertices[], PetscInt faceVertices[], PetscBool *posOriented)
1558 {
1559   const PetscInt *cone = NULL;
1560   PetscInt        coneSize, v, f, v2;
1561   PetscInt        oppositeVertex = -1;
1562   PetscErrorCode  ierr;
1563 
1564   PetscFunctionBegin;
1565   ierr = DMPlexGetConeSize(dm, cell, &coneSize);CHKERRQ(ierr);
1566   ierr = DMPlexGetCone(dm, cell, &cone);CHKERRQ(ierr);
1567   for (v = 0, v2 = 0; v < coneSize; ++v) {
1568     PetscBool found = PETSC_FALSE;
1569 
1570     for (f = 0; f < faceSize; ++f) {
1571       if (face[f] == cone[v]) {
1572         found = PETSC_TRUE; break;
1573       }
1574     }
1575     if (found) {
1576       indices[v2]      = v;
1577       origVertices[v2] = cone[v];
1578       ++v2;
1579     } else {
1580       oppositeVertex = v;
1581     }
1582   }
1583   ierr = DMPlexGetFaceOrientation(dm, cell, numCorners, indices, oppositeVertex, origVertices, faceVertices, posOriented);CHKERRQ(ierr);
1584   PetscFunctionReturn(0);
1585 }
1586 
1587 #undef __FUNCT__
1588 #define __FUNCT__ "DMPlexInsertFace_Internal"
1589 /*
1590   DMPlexInsertFace_Internal - Puts a face into the mesh
1591 
1592   Not collective
1593 
1594   Input Parameters:
1595   + dm              - The DMPlex
1596   . numFaceVertex   - The number of vertices in the face
1597   . faceVertices    - The vertices in the face for dm
1598   . subfaceVertices - The vertices in the face for subdm
1599   . numCorners      - The number of vertices in the cell
1600   . cell            - A cell in dm containing the face
1601   . subcell         - A cell in subdm containing the face
1602   . firstFace       - First face in the mesh
1603   - newFacePoint    - Next face in the mesh
1604 
1605   Output Parameters:
1606   . newFacePoint - Contains next face point number on input, updated on output
1607 
1608   Level: developer
1609 */
1610 static PetscErrorCode DMPlexInsertFace_Internal(DM dm, DM subdm, PetscInt numFaceVertices, const PetscInt faceVertices[], const PetscInt subfaceVertices[], PetscInt numCorners, PetscInt cell, PetscInt subcell, PetscInt firstFace, PetscInt *newFacePoint)
1611 {
1612   MPI_Comm        comm;
1613   DM_Plex        *submesh = (DM_Plex*) subdm->data;
1614   const PetscInt *faces;
1615   PetscInt        numFaces, coneSize;
1616   PetscErrorCode  ierr;
1617 
1618   PetscFunctionBegin;
1619   ierr = PetscObjectGetComm((PetscObject)dm,&comm);CHKERRQ(ierr);
1620   ierr = DMPlexGetConeSize(subdm, subcell, &coneSize);CHKERRQ(ierr);
1621   if (coneSize != 1) SETERRQ2(comm, PETSC_ERR_ARG_OUTOFRANGE, "Cone size of cell %d is %d != 1", cell, coneSize);
1622 #if 0
1623   /* Cannot use this because support() has not been constructed yet */
1624   ierr = DMPlexGetJoin(subdm, numFaceVertices, subfaceVertices, &numFaces, &faces);CHKERRQ(ierr);
1625 #else
1626   {
1627     PetscInt f;
1628 
1629     numFaces = 0;
1630     ierr     = DMGetWorkArray(subdm, 1, PETSC_INT, (void**) &faces);CHKERRQ(ierr);
1631     for (f = firstFace; f < *newFacePoint; ++f) {
1632       PetscInt dof, off, d;
1633 
1634       ierr = PetscSectionGetDof(submesh->coneSection, f, &dof);CHKERRQ(ierr);
1635       ierr = PetscSectionGetOffset(submesh->coneSection, f, &off);CHKERRQ(ierr);
1636       /* Yes, I know this is quadratic, but I expect the sizes to be <5 */
1637       for (d = 0; d < dof; ++d) {
1638         const PetscInt p = submesh->cones[off+d];
1639         PetscInt       v;
1640 
1641         for (v = 0; v < numFaceVertices; ++v) {
1642           if (subfaceVertices[v] == p) break;
1643         }
1644         if (v == numFaceVertices) break;
1645       }
1646       if (d == dof) {
1647         numFaces               = 1;
1648         ((PetscInt*) faces)[0] = f;
1649       }
1650     }
1651   }
1652 #endif
1653   if (numFaces > 1) SETERRQ1(comm, PETSC_ERR_ARG_WRONG, "Vertex set had %d faces, not one", numFaces);
1654   else if (numFaces == 1) {
1655     /* Add the other cell neighbor for this face */
1656     ierr = DMPlexSetCone(subdm, cell, faces);CHKERRQ(ierr);
1657   } else {
1658     PetscInt *indices, *origVertices, *orientedVertices, *orientedSubVertices, v, ov;
1659     PetscBool posOriented;
1660 
1661     ierr                = DMGetWorkArray(subdm, 4*numFaceVertices * sizeof(PetscInt), PETSC_INT, &orientedVertices);CHKERRQ(ierr);
1662     origVertices        = &orientedVertices[numFaceVertices];
1663     indices             = &orientedVertices[numFaceVertices*2];
1664     orientedSubVertices = &orientedVertices[numFaceVertices*3];
1665     ierr                = DMPlexGetOrientedFace(dm, cell, numFaceVertices, faceVertices, numCorners, indices, origVertices, orientedVertices, &posOriented);CHKERRQ(ierr);
1666     /* TODO: I know that routine should return a permutation, not the indices */
1667     for (v = 0; v < numFaceVertices; ++v) {
1668       const PetscInt vertex = faceVertices[v], subvertex = subfaceVertices[v];
1669       for (ov = 0; ov < numFaceVertices; ++ov) {
1670         if (orientedVertices[ov] == vertex) {
1671           orientedSubVertices[ov] = subvertex;
1672           break;
1673         }
1674       }
1675       if (ov == numFaceVertices) SETERRQ1(comm, PETSC_ERR_PLIB, "Could not find face vertex %d in orientated set", vertex);
1676     }
1677     ierr = DMPlexSetCone(subdm, *newFacePoint, orientedSubVertices);CHKERRQ(ierr);
1678     ierr = DMPlexSetCone(subdm, subcell, newFacePoint);CHKERRQ(ierr);
1679     ierr = DMRestoreWorkArray(subdm, 4*numFaceVertices * sizeof(PetscInt), PETSC_INT, &orientedVertices);CHKERRQ(ierr);
1680     ++(*newFacePoint);
1681   }
1682   ierr = DMPlexRestoreJoin(subdm, numFaceVertices, subfaceVertices, &numFaces, &faces);CHKERRQ(ierr);
1683   PetscFunctionReturn(0);
1684 }
1685 
1686 #undef __FUNCT__
1687 #define __FUNCT__ "DMPlexCreateSubmesh_Uninterpolated"
1688 static PetscErrorCode DMPlexCreateSubmesh_Uninterpolated(DM dm, const char vertexLabelName[], DM subdm)
1689 {
1690   MPI_Comm        comm;
1691   DMLabel         vertexLabel, subpointMap;
1692   IS              subvertexIS,  subcellIS;
1693   const PetscInt *subVertices, *subCells;
1694   PetscInt        numSubVertices, firstSubVertex, numSubCells;
1695   PetscInt       *subface, maxConeSize, numSubFaces, firstSubFace, newFacePoint, nFV;
1696   PetscInt        vStart, vEnd, c, f;
1697   PetscErrorCode  ierr;
1698 
1699   PetscFunctionBegin;
1700   ierr = PetscObjectGetComm((PetscObject)dm,&comm);CHKERRQ(ierr);
1701   /* Create subpointMap which marks the submesh */
1702   ierr = DMLabelCreate("subpoint_map", &subpointMap);CHKERRQ(ierr);
1703   ierr = DMPlexSetSubpointMap(subdm, subpointMap);CHKERRQ(ierr);
1704   ierr = DMLabelDestroy(&subpointMap);CHKERRQ(ierr);
1705   ierr = DMPlexGetLabel(dm, vertexLabelName, &vertexLabel);CHKERRQ(ierr);
1706   ierr = DMPlexMarkSubmesh_Uninterpolated(dm, vertexLabel, subpointMap, &numSubFaces, &nFV, subdm);CHKERRQ(ierr);
1707   /* Setup chart */
1708   ierr = DMLabelGetStratumSize(subpointMap, 0, &numSubVertices);CHKERRQ(ierr);
1709   ierr = DMLabelGetStratumSize(subpointMap, 2, &numSubCells);CHKERRQ(ierr);
1710   ierr = DMPlexSetChart(subdm, 0, numSubCells+numSubFaces+numSubVertices);CHKERRQ(ierr);
1711   ierr = DMPlexSetVTKCellHeight(subdm, 1);CHKERRQ(ierr);
1712   /* Set cone sizes */
1713   firstSubVertex = numSubCells;
1714   firstSubFace   = numSubCells+numSubVertices;
1715   newFacePoint   = firstSubFace;
1716   ierr = DMLabelGetStratumIS(subpointMap, 0, &subvertexIS);CHKERRQ(ierr);
1717   if (subvertexIS) {ierr = ISGetIndices(subvertexIS, &subVertices);CHKERRQ(ierr);}
1718   ierr = DMLabelGetStratumIS(subpointMap, 2, &subcellIS);CHKERRQ(ierr);
1719   if (subcellIS) {ierr = ISGetIndices(subcellIS, &subCells);CHKERRQ(ierr);}
1720   for (c = 0; c < numSubCells; ++c) {
1721     ierr = DMPlexSetConeSize(subdm, c, 1);CHKERRQ(ierr);
1722   }
1723   for (f = firstSubFace; f < firstSubFace+numSubFaces; ++f) {
1724     ierr = DMPlexSetConeSize(subdm, f, nFV);CHKERRQ(ierr);
1725   }
1726   ierr = DMSetUp(subdm);CHKERRQ(ierr);
1727   /* Create face cones */
1728   ierr = DMPlexGetDepthStratum(dm, 0, &vStart, &vEnd);CHKERRQ(ierr);
1729   ierr = DMPlexGetMaxSizes(dm, &maxConeSize, NULL);CHKERRQ(ierr);
1730   ierr = DMGetWorkArray(subdm, maxConeSize, PETSC_INT, (void**) &subface);CHKERRQ(ierr);
1731   for (c = 0; c < numSubCells; ++c) {
1732     const PetscInt cell    = subCells[c];
1733     const PetscInt subcell = c;
1734     PetscInt      *closure = NULL;
1735     PetscInt       closureSize, cl, numCorners = 0, faceSize = 0;
1736 
1737     ierr = DMPlexGetTransitiveClosure(dm, cell, PETSC_TRUE, &closureSize, &closure);CHKERRQ(ierr);
1738     for (cl = 0; cl < closureSize*2; cl += 2) {
1739       const PetscInt point = closure[cl];
1740       PetscInt       subVertex;
1741 
1742       if ((point >= vStart) && (point < vEnd)) {
1743         ++numCorners;
1744         ierr = PetscFindInt(point, numSubVertices, subVertices, &subVertex);CHKERRQ(ierr);
1745         if (subVertex >= 0) {
1746           closure[faceSize] = point;
1747           subface[faceSize] = firstSubVertex+subVertex;
1748           ++faceSize;
1749         }
1750       }
1751     }
1752     if (faceSize > nFV) SETERRQ1(comm, PETSC_ERR_ARG_WRONG, "Invalid submesh: Too many vertices %d of an element on the surface", faceSize);
1753     if (faceSize == nFV) {
1754       ierr = DMPlexInsertFace_Internal(dm, subdm, faceSize, closure, subface, numCorners, cell, subcell, firstSubFace, &newFacePoint);CHKERRQ(ierr);
1755     }
1756     ierr = DMPlexRestoreTransitiveClosure(dm, cell, PETSC_TRUE, &closureSize, &closure);CHKERRQ(ierr);
1757   }
1758   ierr = DMRestoreWorkArray(subdm, maxConeSize, PETSC_INT, (void**) &subface);CHKERRQ(ierr);
1759   ierr = DMPlexSymmetrize(subdm);CHKERRQ(ierr);
1760   ierr = DMPlexStratify(subdm);CHKERRQ(ierr);
1761   /* Build coordinates */
1762   {
1763     PetscSection coordSection, subCoordSection;
1764     Vec          coordinates, subCoordinates;
1765     PetscScalar *coords, *subCoords;
1766     PetscInt     coordSize, v;
1767 
1768     ierr = DMPlexGetCoordinateSection(dm, &coordSection);CHKERRQ(ierr);
1769     ierr = DMGetCoordinatesLocal(dm, &coordinates);CHKERRQ(ierr);
1770     ierr = DMPlexGetCoordinateSection(subdm, &subCoordSection);CHKERRQ(ierr);
1771     ierr = PetscSectionSetChart(subCoordSection, firstSubVertex, firstSubVertex+numSubVertices);CHKERRQ(ierr);
1772     for (v = 0; v < numSubVertices; ++v) {
1773       const PetscInt vertex    = subVertices[v];
1774       const PetscInt subvertex = firstSubVertex+v;
1775       PetscInt       dof;
1776 
1777       ierr = PetscSectionGetDof(coordSection, vertex, &dof);CHKERRQ(ierr);
1778       ierr = PetscSectionSetDof(subCoordSection, subvertex, dof);CHKERRQ(ierr);
1779     }
1780     ierr = PetscSectionSetUp(subCoordSection);CHKERRQ(ierr);
1781     ierr = PetscSectionGetStorageSize(subCoordSection, &coordSize);CHKERRQ(ierr);
1782     ierr = VecCreate(comm, &subCoordinates);CHKERRQ(ierr);
1783     ierr = VecSetSizes(subCoordinates, coordSize, PETSC_DETERMINE);CHKERRQ(ierr);
1784     ierr = VecSetFromOptions(subCoordinates);CHKERRQ(ierr);
1785     ierr = VecGetArray(coordinates,    &coords);CHKERRQ(ierr);
1786     ierr = VecGetArray(subCoordinates, &subCoords);CHKERRQ(ierr);
1787     for (v = 0; v < numSubVertices; ++v) {
1788       const PetscInt vertex    = subVertices[v];
1789       const PetscInt subvertex = firstSubVertex+v;
1790       PetscInt       dof, off, sdof, soff, d;
1791 
1792       ierr = PetscSectionGetDof(coordSection, vertex, &dof);CHKERRQ(ierr);
1793       ierr = PetscSectionGetOffset(coordSection, vertex, &off);CHKERRQ(ierr);
1794       ierr = PetscSectionGetDof(subCoordSection, subvertex, &sdof);CHKERRQ(ierr);
1795       ierr = PetscSectionGetOffset(subCoordSection, subvertex, &soff);CHKERRQ(ierr);
1796       if (dof != sdof) SETERRQ4(comm, PETSC_ERR_PLIB, "Coordinate dimension %d on subvertex %d, vertex %d should be %d", sdof, subvertex, vertex, dof);
1797       for (d = 0; d < dof; ++d) subCoords[soff+d] = coords[off+d];
1798     }
1799     ierr = VecRestoreArray(coordinates,    &coords);CHKERRQ(ierr);
1800     ierr = VecRestoreArray(subCoordinates, &subCoords);CHKERRQ(ierr);
1801     ierr = DMSetCoordinatesLocal(subdm, subCoordinates);CHKERRQ(ierr);
1802     ierr = VecDestroy(&subCoordinates);CHKERRQ(ierr);
1803   }
1804   /* Cleanup */
1805   if (subvertexIS) {ierr = ISRestoreIndices(subvertexIS, &subVertices);CHKERRQ(ierr);}
1806   ierr = ISDestroy(&subvertexIS);CHKERRQ(ierr);
1807   if (subcellIS) {ierr = ISRestoreIndices(subcellIS, &subCells);CHKERRQ(ierr);}
1808   ierr = ISDestroy(&subcellIS);CHKERRQ(ierr);
1809   PetscFunctionReturn(0);
1810 }
1811 
1812 #undef __FUNCT__
1813 #define __FUNCT__ "DMPlexCreateSubmesh_Interpolated"
1814 static PetscErrorCode DMPlexCreateSubmesh_Interpolated(DM dm, const char vertexLabelName[], DM subdm)
1815 {
1816   MPI_Comm         comm;
1817   DMLabel          subpointMap, vertexLabel;
1818   IS              *subpointIS;
1819   const PetscInt **subpoints;
1820   PetscInt        *numSubPoints, *firstSubPoint, *coneNew;
1821   PetscInt         totSubPoints = 0, maxConeSize, dim, p, d, v;
1822   PetscErrorCode   ierr;
1823 
1824   PetscFunctionBegin;
1825   ierr = PetscObjectGetComm((PetscObject)dm,&comm);CHKERRQ(ierr);
1826   /* Create subpointMap which marks the submesh */
1827   ierr = DMLabelCreate("subpoint_map", &subpointMap);CHKERRQ(ierr);
1828   ierr = DMPlexSetSubpointMap(subdm, subpointMap);CHKERRQ(ierr);
1829   ierr = DMLabelDestroy(&subpointMap);CHKERRQ(ierr);
1830   ierr = DMPlexGetLabel(dm, vertexLabelName, &vertexLabel);CHKERRQ(ierr);
1831   ierr = DMPlexMarkSubmesh_Interpolated(dm, vertexLabel, subpointMap, subdm);CHKERRQ(ierr);
1832   /* Setup chart */
1833   ierr = DMPlexGetDimension(dm, &dim);CHKERRQ(ierr);
1834   ierr = PetscMalloc4(dim+1,PetscInt,&numSubPoints,dim+1,PetscInt,&firstSubPoint,dim+1,IS,&subpointIS,dim+1,const PetscInt *,&subpoints);CHKERRQ(ierr);
1835   for (d = 0; d <= dim; ++d) {
1836     ierr = DMLabelGetStratumSize(subpointMap, d, &numSubPoints[d]);CHKERRQ(ierr);
1837     totSubPoints += numSubPoints[d];
1838   }
1839   ierr = DMPlexSetChart(subdm, 0, totSubPoints);CHKERRQ(ierr);
1840   ierr = DMPlexSetVTKCellHeight(subdm, 1);CHKERRQ(ierr);
1841   /* Set cone sizes */
1842   firstSubPoint[dim] = 0;
1843   firstSubPoint[0]   = firstSubPoint[dim] + numSubPoints[dim];
1844   if (dim > 1) {firstSubPoint[dim-1] = firstSubPoint[0]     + numSubPoints[0];}
1845   if (dim > 2) {firstSubPoint[dim-2] = firstSubPoint[dim-1] + numSubPoints[dim-1];}
1846   for (d = 0; d <= dim; ++d) {
1847     ierr = DMLabelGetStratumIS(subpointMap, d, &subpointIS[d]);CHKERRQ(ierr);
1848     ierr = ISGetIndices(subpointIS[d], &subpoints[d]);CHKERRQ(ierr);
1849   }
1850   for (d = 0; d <= dim; ++d) {
1851     for (p = 0; p < numSubPoints[d]; ++p) {
1852       const PetscInt  point    = subpoints[d][p];
1853       const PetscInt  subpoint = firstSubPoint[d] + p;
1854       const PetscInt *cone;
1855       PetscInt        coneSize, coneSizeNew, c, val;
1856 
1857       ierr = DMPlexGetConeSize(dm, point, &coneSize);CHKERRQ(ierr);
1858       ierr = DMPlexSetConeSize(subdm, subpoint, coneSize);CHKERRQ(ierr);
1859       if (d == dim) {
1860         ierr = DMPlexGetCone(dm, point, &cone);CHKERRQ(ierr);
1861         for (c = 0, coneSizeNew = 0; c < coneSize; ++c) {
1862           ierr = DMLabelGetValue(subpointMap, cone[c], &val);CHKERRQ(ierr);
1863           if (val >= 0) coneSizeNew++;
1864         }
1865         ierr = DMPlexSetConeSize(subdm, subpoint, coneSizeNew);CHKERRQ(ierr);
1866       }
1867     }
1868   }
1869   ierr = DMSetUp(subdm);CHKERRQ(ierr);
1870   /* Set cones */
1871   ierr = DMPlexGetMaxSizes(dm, &maxConeSize, NULL);CHKERRQ(ierr);
1872   ierr = PetscMalloc(maxConeSize * sizeof(PetscInt), &coneNew);CHKERRQ(ierr);
1873   for (d = 0; d <= dim; ++d) {
1874     for (p = 0; p < numSubPoints[d]; ++p) {
1875       const PetscInt  point    = subpoints[d][p];
1876       const PetscInt  subpoint = firstSubPoint[d] + p;
1877       const PetscInt *cone;
1878       PetscInt        coneSize, subconeSize, coneSizeNew, c, subc;
1879 
1880       ierr = DMPlexGetConeSize(dm, point, &coneSize);CHKERRQ(ierr);
1881       ierr = DMPlexGetConeSize(subdm, subpoint, &subconeSize);CHKERRQ(ierr);
1882       ierr = DMPlexGetCone(dm, point, &cone);CHKERRQ(ierr);
1883       for (c = 0, coneSizeNew = 0; c < coneSize; ++c) {
1884         ierr = PetscFindInt(cone[c], numSubPoints[d-1], subpoints[d-1], &subc);CHKERRQ(ierr);
1885         if (subc >= 0) coneNew[coneSizeNew++] = firstSubPoint[d-1] + subc;
1886       }
1887       if (coneSizeNew != subconeSize) SETERRQ2(comm, PETSC_ERR_PLIB, "Number of cone points located %d does not match subcone size %d", coneSizeNew, subconeSize);
1888       ierr = DMPlexSetCone(subdm, subpoint, coneNew);CHKERRQ(ierr);
1889     }
1890   }
1891   ierr = PetscFree(coneNew);CHKERRQ(ierr);
1892   ierr = DMPlexSymmetrize(subdm);CHKERRQ(ierr);
1893   ierr = DMPlexStratify(subdm);CHKERRQ(ierr);
1894   /* Build coordinates */
1895   {
1896     PetscSection coordSection, subCoordSection;
1897     Vec          coordinates, subCoordinates;
1898     PetscScalar *coords, *subCoords;
1899     PetscInt     coordSize;
1900 
1901     ierr = DMPlexGetCoordinateSection(dm, &coordSection);CHKERRQ(ierr);
1902     ierr = DMGetCoordinatesLocal(dm, &coordinates);CHKERRQ(ierr);
1903     ierr = DMPlexGetCoordinateSection(subdm, &subCoordSection);CHKERRQ(ierr);
1904     ierr = PetscSectionSetChart(subCoordSection, firstSubPoint[0], firstSubPoint[0]+numSubPoints[0]);CHKERRQ(ierr);
1905     for (v = 0; v < numSubPoints[0]; ++v) {
1906       const PetscInt vertex    = subpoints[0][v];
1907       const PetscInt subvertex = firstSubPoint[0]+v;
1908       PetscInt       dof;
1909 
1910       ierr = PetscSectionGetDof(coordSection, vertex, &dof);CHKERRQ(ierr);
1911       ierr = PetscSectionSetDof(subCoordSection, subvertex, dof);CHKERRQ(ierr);
1912     }
1913     ierr = PetscSectionSetUp(subCoordSection);CHKERRQ(ierr);
1914     ierr = PetscSectionGetStorageSize(subCoordSection, &coordSize);CHKERRQ(ierr);
1915     ierr = VecCreate(comm, &subCoordinates);CHKERRQ(ierr);
1916     ierr = VecSetSizes(subCoordinates, coordSize, PETSC_DETERMINE);CHKERRQ(ierr);
1917     ierr = VecSetFromOptions(subCoordinates);CHKERRQ(ierr);
1918     ierr = VecGetArray(coordinates,    &coords);CHKERRQ(ierr);
1919     ierr = VecGetArray(subCoordinates, &subCoords);CHKERRQ(ierr);
1920     for (v = 0; v < numSubPoints[0]; ++v) {
1921       const PetscInt vertex    = subpoints[0][v];
1922       const PetscInt subvertex = firstSubPoint[0]+v;
1923       PetscInt dof, off, sdof, soff, d;
1924 
1925       ierr = PetscSectionGetDof(coordSection, vertex, &dof);CHKERRQ(ierr);
1926       ierr = PetscSectionGetOffset(coordSection, vertex, &off);CHKERRQ(ierr);
1927       ierr = PetscSectionGetDof(subCoordSection, subvertex, &sdof);CHKERRQ(ierr);
1928       ierr = PetscSectionGetOffset(subCoordSection, subvertex, &soff);CHKERRQ(ierr);
1929       if (dof != sdof) SETERRQ4(comm, PETSC_ERR_PLIB, "Coordinate dimension %d on subvertex %d, vertex %d should be %d", sdof, subvertex, vertex, dof);
1930       for (d = 0; d < dof; ++d) subCoords[soff+d] = coords[off+d];
1931     }
1932     ierr = VecRestoreArray(coordinates,    &coords);CHKERRQ(ierr);
1933     ierr = VecRestoreArray(subCoordinates, &subCoords);CHKERRQ(ierr);
1934     ierr = DMSetCoordinatesLocal(subdm, subCoordinates);CHKERRQ(ierr);
1935     ierr = VecDestroy(&subCoordinates);CHKERRQ(ierr);
1936   }
1937   /* Cleanup */
1938   for (d = 0; d <= dim; ++d) {
1939     ierr = ISRestoreIndices(subpointIS[d], &subpoints[d]);CHKERRQ(ierr);
1940     ierr = ISDestroy(&subpointIS[d]);CHKERRQ(ierr);
1941   }
1942   ierr = PetscFree4(numSubPoints,firstSubPoint,subpointIS,subpoints);CHKERRQ(ierr);
1943   PetscFunctionReturn(0);
1944 }
1945 
1946 #undef __FUNCT__
1947 #define __FUNCT__ "DMPlexCreateSubmesh"
1948 /*
1949   DMPlexCreateSubmesh - Extract a hypersurface from the mesh using vertices defined by a label
1950 
1951   Input Parameters:
1952 + dm           - The original mesh
1953 - vertexLabel  - The DMLabel marking vertices contained in the surface
1954 
1955   Output Parameter:
1956 . subdm - The surface mesh
1957 
1958   Note: This function produces a DMLabel mapping original points in the submesh to their depth. This can be obtained using DMPlexGetSubpointMap().
1959 
1960   Level: developer
1961 
1962 .seealso: DMPlexGetSubpointMap(), DMPlexGetLabel(), DMLabelSetValue()
1963 */
1964 PetscErrorCode DMPlexCreateSubmesh(DM dm, const char vertexLabel[], DM *subdm)
1965 {
1966   PetscInt       dim, depth;
1967   PetscErrorCode ierr;
1968 
1969   PetscFunctionBegin;
1970   PetscValidHeaderSpecific(dm, DM_CLASSID, 1);
1971   PetscValidCharPointer(vertexLabel, 2);
1972   PetscValidPointer(subdm, 4);
1973   ierr = DMPlexGetDimension(dm, &dim);CHKERRQ(ierr);
1974   ierr = DMPlexGetDepth(dm, &depth);CHKERRQ(ierr);
1975   ierr = DMCreate(PetscObjectComm((PetscObject)dm), subdm);CHKERRQ(ierr);
1976   ierr = DMSetType(*subdm, DMPLEX);CHKERRQ(ierr);
1977   ierr = DMPlexSetDimension(*subdm, dim-1);CHKERRQ(ierr);
1978   if (depth == dim) {
1979     ierr = DMPlexCreateSubmesh_Interpolated(dm, vertexLabel, *subdm);CHKERRQ(ierr);
1980   } else {
1981     ierr = DMPlexCreateSubmesh_Uninterpolated(dm, vertexLabel, *subdm);CHKERRQ(ierr);
1982   }
1983   PetscFunctionReturn(0);
1984 }
1985 
1986 #undef __FUNCT__
1987 #define __FUNCT__ "DMPlexGetSubpointMap"
1988 PetscErrorCode DMPlexGetSubpointMap(DM dm, DMLabel *subpointMap)
1989 {
1990   DM_Plex *mesh = (DM_Plex*) dm->data;
1991 
1992   PetscFunctionBegin;
1993   PetscValidHeaderSpecific(dm, DM_CLASSID, 1);
1994   PetscValidPointer(subpointMap, 2);
1995   *subpointMap = mesh->subpointMap;
1996   PetscFunctionReturn(0);
1997 }
1998 
1999 #undef __FUNCT__
2000 #define __FUNCT__ "DMPlexSetSubpointMap"
2001 /* Note: Should normally not be called by the user, since it is set in DMPlexCreateSubmesh() */
2002 PetscErrorCode DMPlexSetSubpointMap(DM dm, DMLabel subpointMap)
2003 {
2004   DM_Plex       *mesh = (DM_Plex *) dm->data;
2005   PetscErrorCode ierr;
2006 
2007   PetscFunctionBegin;
2008   PetscValidHeaderSpecific(dm, DM_CLASSID, 1);
2009   ierr = DMLabelDestroy(&mesh->subpointMap);CHKERRQ(ierr);
2010   mesh->subpointMap = subpointMap;
2011   ++mesh->subpointMap->refct;CHKERRQ(ierr);
2012   PetscFunctionReturn(0);
2013 }
2014 
2015 #undef __FUNCT__
2016 #define __FUNCT__ "DMPlexCreateSubpointIS"
2017 /*
2018   DMPlexCreateSubpointIS - Creates an IS covering the entire subdm chart with the original points as data
2019 
2020   Input Parameter:
2021 . dm - The submesh DM
2022 
2023   Output Parameter:
2024 . subpointIS - The IS of all the points from the original mesh in this submesh, or NULL if this is not a submesh
2025 
2026   Note: This is IS is guaranteed to be sorted by the construction of the submesh
2027 */
2028 PetscErrorCode DMPlexCreateSubpointIS(DM dm, IS *subpointIS)
2029 {
2030   MPI_Comm        comm;
2031   DMLabel         subpointMap;
2032   IS              is;
2033   const PetscInt *opoints;
2034   PetscInt       *points, *depths;
2035   PetscInt        depth, depStart, depEnd, d, pStart, pEnd, p, n, off;
2036   PetscErrorCode  ierr;
2037 
2038   PetscFunctionBegin;
2039   PetscValidHeaderSpecific(dm, DM_CLASSID, 1);
2040   PetscValidPointer(subpointIS, 2);
2041   ierr = PetscObjectGetComm((PetscObject)dm,&comm);CHKERRQ(ierr);
2042   *subpointIS = NULL;
2043   ierr = DMPlexGetSubpointMap(dm, &subpointMap);CHKERRQ(ierr);
2044   if (subpointMap) {
2045     ierr = DMPlexGetDepth(dm, &depth);CHKERRQ(ierr);
2046     ierr = DMPlexGetChart(dm, &pStart, &pEnd);CHKERRQ(ierr);
2047     if (pStart) SETERRQ1(comm, PETSC_ERR_ARG_WRONG, "Submeshes must start the point numbering at 0, not %d", pStart);
2048     ierr = DMGetWorkArray(dm, depth+1, PETSC_INT, &depths);CHKERRQ(ierr);
2049     depths[0] = depth;
2050     depths[1] = 0;
2051     for(d = 2; d <= depth; ++d) {depths[d] = depth+1 - d;}
2052     ierr = PetscMalloc(pEnd * sizeof(PetscInt), &points);CHKERRQ(ierr);
2053     for(d = 0, off = 0; d <= depth; ++d) {
2054       const PetscInt dep = depths[d];
2055 
2056       ierr = DMPlexGetDepthStratum(dm, dep, &depStart, &depEnd);CHKERRQ(ierr);
2057       ierr = DMLabelGetStratumSize(subpointMap, dep, &n);CHKERRQ(ierr);
2058       if (((d < 2) && (depth > 1)) || (d == 1)) { /* Only check vertices and cells for now since the map is broken for others */
2059         if (n != depEnd-depStart) SETERRQ3(comm, PETSC_ERR_ARG_WRONG, "The number of mapped submesh points %d at depth %d should be %d", n, dep, depEnd-depStart);
2060       } else {
2061         if (!n) {
2062           if (d == 0) {
2063             /* Missing cells */
2064             for(p = 0; p < depEnd-depStart; ++p, ++off) points[off] = -1;
2065           } else {
2066             /* Missing faces */
2067             for(p = 0; p < depEnd-depStart; ++p, ++off) points[off] = PETSC_MAX_INT;
2068           }
2069         }
2070       }
2071       if (n) {
2072         ierr = DMLabelGetStratumIS(subpointMap, dep, &is);CHKERRQ(ierr);
2073         ierr = ISGetIndices(is, &opoints);CHKERRQ(ierr);
2074         for(p = 0; p < n; ++p, ++off) points[off] = opoints[p];
2075         ierr = ISRestoreIndices(is, &opoints);CHKERRQ(ierr);
2076         ierr = ISDestroy(&is);CHKERRQ(ierr);
2077       }
2078     }
2079     ierr = DMRestoreWorkArray(dm, depth+1, PETSC_INT, &depths);CHKERRQ(ierr);
2080     if (off != pEnd) SETERRQ2(comm, PETSC_ERR_ARG_WRONG, "The number of mapped submesh points %d should be %d", off, pEnd);
2081     ierr = ISCreateGeneral(comm, pEnd, points, PETSC_OWN_POINTER, subpointIS);CHKERRQ(ierr);
2082   }
2083   PetscFunctionReturn(0);
2084 }
2085