xref: /petsc/src/dm/impls/plex/plexsubmesh.c (revision 3cf725829722bbed11c247f4c19c417cde988f81)
1 #include <petsc-private/dmpleximpl.h>   /*I      "petscdmplex.h"   I*/
2 #include <petscsf.h>
3 
4 #undef __FUNCT__
5 #define __FUNCT__ "DMPlexMarkBoundaryFaces"
6 /*@
7   DMPlexMarkBoundaryFaces - Mark all faces on the boundary
8 
9   Not Collective
10 
11   Input Parameter:
12 . dm - The original DM
13 
14   Output Parameter:
15 . label - The DMLabel marking boundary faces with value 1
16 
17   Level: developer
18 
19 .seealso: DMLabelCreate(), DMPlexCreateLabel()
20 @*/
21 PetscErrorCode DMPlexMarkBoundaryFaces(DM dm, DMLabel label)
22 {
23   PetscInt       fStart, fEnd, f;
24   PetscErrorCode ierr;
25 
26   PetscFunctionBegin;
27   PetscValidHeaderSpecific(dm, DM_CLASSID, 1);
28   ierr = DMPlexGetHeightStratum(dm, 1, &fStart, &fEnd);CHKERRQ(ierr);
29   for (f = fStart; f < fEnd; ++f) {
30     PetscInt supportSize;
31 
32     ierr = DMPlexGetSupportSize(dm, f, &supportSize);CHKERRQ(ierr);
33     if (supportSize == 1) {
34       ierr = DMLabelSetValue(label, f, 1);CHKERRQ(ierr);
35     }
36   }
37   PetscFunctionReturn(0);
38 }
39 
40 #undef __FUNCT__
41 #define __FUNCT__ "DMPlexLabelComplete"
42 /*@
43   DMPlexLabelComplete - Starting with a label marking points on a surface, we add the transitive closure to the surface
44 
45   Input Parameters:
46 + dm - The DM
47 - label - A DMLabel marking the surface points
48 
49   Output Parameter:
50 . label - A DMLabel marking all surface points in the transitive closure
51 
52   Level: developer
53 
54 .seealso: DMPlexLabelCohesiveComplete()
55 @*/
56 PetscErrorCode DMPlexLabelComplete(DM dm, DMLabel label)
57 {
58   IS              valueIS;
59   const PetscInt *values;
60   PetscInt        numValues, v;
61   PetscErrorCode  ierr;
62 
63   PetscFunctionBegin;
64   ierr = DMLabelGetNumValues(label, &numValues);CHKERRQ(ierr);
65   ierr = DMLabelGetValueIS(label, &valueIS);CHKERRQ(ierr);
66   ierr = ISGetIndices(valueIS, &values);CHKERRQ(ierr);
67   for (v = 0; v < numValues; ++v) {
68     IS              pointIS;
69     const PetscInt *points;
70     PetscInt        numPoints, p;
71 
72     ierr = DMLabelGetStratumSize(label, values[v], &numPoints);CHKERRQ(ierr);
73     ierr = DMLabelGetStratumIS(label, values[v], &pointIS);CHKERRQ(ierr);
74     ierr = ISGetIndices(pointIS, &points);CHKERRQ(ierr);
75     for (p = 0; p < numPoints; ++p) {
76       PetscInt *closure = NULL;
77       PetscInt  closureSize, c;
78 
79       ierr = DMPlexGetTransitiveClosure(dm, points[p], PETSC_TRUE, &closureSize, &closure);CHKERRQ(ierr);
80       for (c = 0; c < closureSize*2; c += 2) {
81         ierr = DMLabelSetValue(label, closure[c], values[v]);CHKERRQ(ierr);
82       }
83       ierr = DMPlexRestoreTransitiveClosure(dm, points[p], PETSC_TRUE, &closureSize, &closure);CHKERRQ(ierr);
84     }
85     ierr = ISRestoreIndices(pointIS, &points);CHKERRQ(ierr);
86     ierr = ISDestroy(&pointIS);CHKERRQ(ierr);
87   }
88   ierr = ISRestoreIndices(valueIS, &values);CHKERRQ(ierr);
89   ierr = ISDestroy(&valueIS);CHKERRQ(ierr);
90   PetscFunctionReturn(0);
91 }
92 
93 #undef __FUNCT__
94 #define __FUNCT__ "DMPlexShiftPoint_Internal"
95 PETSC_STATIC_INLINE PetscInt DMPlexShiftPoint_Internal(PetscInt p, PetscInt depth, PetscInt depthEnd[], PetscInt depthShift[])
96 {
97   if (depth < 0) return p;
98   /* Cells    */ if (p < depthEnd[depth])   return p;
99   /* Vertices */ if (p < depthEnd[0])       return p + depthShift[depth];
100   /* Faces    */ if (p < depthEnd[depth-1]) return p + depthShift[depth] + depthShift[0];
101   /* Edges    */                            return p + depthShift[depth] + depthShift[0] + depthShift[depth-1];
102 }
103 
104 #undef __FUNCT__
105 #define __FUNCT__ "DMPlexShiftSizes_Internal"
106 static PetscErrorCode DMPlexShiftSizes_Internal(DM dm, PetscInt depthShift[], DM dmNew)
107 {
108   PetscInt      *depthEnd;
109   PetscInt       depth = 0, d, pStart, pEnd, p;
110   PetscErrorCode ierr;
111 
112   PetscFunctionBegin;
113   ierr = DMPlexGetDepth(dm, &depth);CHKERRQ(ierr);
114   if (depth < 0) PetscFunctionReturn(0);
115   ierr = PetscMalloc((depth+1) * sizeof(PetscInt), &depthEnd);CHKERRQ(ierr);
116   /* Step 1: Expand chart */
117   ierr = DMPlexGetChart(dm, &pStart, &pEnd);CHKERRQ(ierr);
118   for (d = 0; d <= depth; ++d) {
119     pEnd += depthShift[d];
120     ierr  = DMPlexGetDepthStratum(dm, d, NULL, &depthEnd[d]);CHKERRQ(ierr);
121   }
122   ierr = DMPlexSetChart(dmNew, pStart, pEnd);CHKERRQ(ierr);
123   /* Step 2: Set cone and support sizes */
124   for (d = 0; d <= depth; ++d) {
125     ierr = DMPlexGetDepthStratum(dm, d, &pStart, &pEnd);CHKERRQ(ierr);
126     for (p = pStart; p < pEnd; ++p) {
127       PetscInt newp = DMPlexShiftPoint_Internal(p, depth, depthEnd, depthShift);
128       PetscInt size;
129 
130       ierr = DMPlexGetConeSize(dm, p, &size);CHKERRQ(ierr);
131       ierr = DMPlexSetConeSize(dmNew, newp, size);CHKERRQ(ierr);
132       ierr = DMPlexGetSupportSize(dm, p, &size);CHKERRQ(ierr);
133       ierr = DMPlexSetSupportSize(dmNew, newp, size);CHKERRQ(ierr);
134     }
135   }
136   ierr = PetscFree(depthEnd);CHKERRQ(ierr);
137   PetscFunctionReturn(0);
138 }
139 
140 #undef __FUNCT__
141 #define __FUNCT__ "DMPlexShiftPoints_Internal"
142 static PetscErrorCode DMPlexShiftPoints_Internal(DM dm, PetscInt depthShift[], DM dmNew)
143 {
144   PetscInt      *depthEnd, *newpoints;
145   PetscInt       depth = 0, d, maxConeSize, maxSupportSize, pStart, pEnd, p;
146   PetscErrorCode ierr;
147 
148   PetscFunctionBegin;
149   ierr = DMPlexGetDepth(dm, &depth);CHKERRQ(ierr);
150   if (depth < 0) PetscFunctionReturn(0);
151   ierr = DMPlexGetMaxSizes(dm, &maxConeSize, &maxSupportSize);CHKERRQ(ierr);
152   ierr = PetscMalloc2(depth+1,PetscInt,&depthEnd,PetscMax(maxConeSize, maxSupportSize),PetscInt,&newpoints);CHKERRQ(ierr);
153   for (d = 0; d <= depth; ++d) {
154     ierr = DMPlexGetDepthStratum(dm, d, NULL, &depthEnd[d]);CHKERRQ(ierr);
155   }
156   /* Step 5: Set cones and supports */
157   ierr = DMPlexGetChart(dm, &pStart, &pEnd);CHKERRQ(ierr);
158   for (p = pStart; p < pEnd; ++p) {
159     const PetscInt *points = NULL, *orientations = NULL;
160     PetscInt        size, i, newp = DMPlexShiftPoint_Internal(p, depth, depthEnd, depthShift);
161 
162     ierr = DMPlexGetConeSize(dm, p, &size);CHKERRQ(ierr);
163     ierr = DMPlexGetCone(dm, p, &points);CHKERRQ(ierr);
164     ierr = DMPlexGetConeOrientation(dm, p, &orientations);CHKERRQ(ierr);
165     for (i = 0; i < size; ++i) {
166       newpoints[i] = DMPlexShiftPoint_Internal(points[i], depth, depthEnd, depthShift);
167     }
168     ierr = DMPlexSetCone(dmNew, newp, newpoints);CHKERRQ(ierr);
169     ierr = DMPlexSetConeOrientation(dmNew, newp, orientations);CHKERRQ(ierr);
170     ierr = DMPlexGetSupportSize(dm, p, &size);CHKERRQ(ierr);
171     ierr = DMPlexGetSupport(dm, p, &points);CHKERRQ(ierr);
172     for (i = 0; i < size; ++i) {
173       newpoints[i] = DMPlexShiftPoint_Internal(points[i], depth, depthEnd, depthShift);
174     }
175     ierr = DMPlexSetSupport(dmNew, newp, newpoints);CHKERRQ(ierr);
176   }
177   ierr = PetscFree2(depthEnd,newpoints);CHKERRQ(ierr);
178   PetscFunctionReturn(0);
179 }
180 
181 #undef __FUNCT__
182 #define __FUNCT__ "DMPlexShiftCoordinates_Internal"
183 static PetscErrorCode DMPlexShiftCoordinates_Internal(DM dm, PetscInt depthShift[], DM dmNew)
184 {
185   PetscSection   coordSection, newCoordSection;
186   Vec            coordinates, newCoordinates;
187   PetscScalar   *coords, *newCoords;
188   PetscInt      *depthEnd, coordSize;
189   PetscInt       dim, depth = 0, d, vStart, vEnd, vStartNew, vEndNew, v;
190   PetscErrorCode ierr;
191 
192   PetscFunctionBegin;
193   ierr = DMPlexGetDimension(dm, &dim);CHKERRQ(ierr);
194   ierr = DMPlexGetDepth(dm, &depth);CHKERRQ(ierr);
195   ierr = PetscMalloc((depth+1) * sizeof(PetscInt), &depthEnd);CHKERRQ(ierr);
196   for (d = 0; d <= depth; ++d) {
197     ierr = DMPlexGetDepthStratum(dm, d, NULL, &depthEnd[d]);CHKERRQ(ierr);
198   }
199   /* Step 8: Convert coordinates */
200   ierr = DMPlexGetDepthStratum(dm, 0, &vStart, &vEnd);CHKERRQ(ierr);
201   ierr = DMPlexGetDepthStratum(dmNew, 0, &vStartNew, &vEndNew);CHKERRQ(ierr);
202   ierr = DMPlexGetCoordinateSection(dm, &coordSection);CHKERRQ(ierr);
203   ierr = PetscSectionCreate(PetscObjectComm((PetscObject)dm), &newCoordSection);CHKERRQ(ierr);
204   ierr = PetscSectionSetNumFields(newCoordSection, 1);CHKERRQ(ierr);
205   ierr = PetscSectionSetFieldComponents(newCoordSection, 0, dim);CHKERRQ(ierr);
206   ierr = PetscSectionSetChart(newCoordSection, vStartNew, vEndNew);CHKERRQ(ierr);
207   for (v = vStartNew; v < vEndNew; ++v) {
208     ierr = PetscSectionSetDof(newCoordSection, v, dim);CHKERRQ(ierr);
209     ierr = PetscSectionSetFieldDof(newCoordSection, v, 0, dim);CHKERRQ(ierr);
210   }
211   ierr = PetscSectionSetUp(newCoordSection);CHKERRQ(ierr);
212   ierr = DMPlexSetCoordinateSection(dmNew, newCoordSection);CHKERRQ(ierr);
213   ierr = PetscSectionGetStorageSize(newCoordSection, &coordSize);CHKERRQ(ierr);
214   ierr = VecCreate(PetscObjectComm((PetscObject)dm), &newCoordinates);CHKERRQ(ierr);
215   ierr = PetscObjectSetName((PetscObject) newCoordinates, "coordinates");CHKERRQ(ierr);
216   ierr = VecSetSizes(newCoordinates, coordSize, PETSC_DETERMINE);CHKERRQ(ierr);
217   ierr = VecSetType(newCoordinates,dm->vectype);CHKERRQ(ierr);
218   ierr = DMSetCoordinatesLocal(dmNew, newCoordinates);CHKERRQ(ierr);
219   ierr = DMGetCoordinatesLocal(dm, &coordinates);CHKERRQ(ierr);
220   ierr = VecGetArray(coordinates, &coords);CHKERRQ(ierr);
221   ierr = VecGetArray(newCoordinates, &newCoords);CHKERRQ(ierr);
222   for (v = vStart; v < vEnd; ++v) {
223     PetscInt dof, off, noff, d;
224 
225     ierr = PetscSectionGetDof(coordSection, v, &dof);CHKERRQ(ierr);
226     ierr = PetscSectionGetOffset(coordSection, v, &off);CHKERRQ(ierr);
227     ierr = PetscSectionGetOffset(newCoordSection, DMPlexShiftPoint_Internal(v, depth, depthEnd, depthShift), &noff);CHKERRQ(ierr);
228     for (d = 0; d < dof; ++d) {
229       newCoords[noff+d] = coords[off+d];
230     }
231   }
232   ierr = VecRestoreArray(coordinates, &coords);CHKERRQ(ierr);
233   ierr = VecRestoreArray(newCoordinates, &newCoords);CHKERRQ(ierr);
234   ierr = VecDestroy(&newCoordinates);CHKERRQ(ierr);
235   ierr = PetscSectionDestroy(&newCoordSection);CHKERRQ(ierr);
236   ierr = PetscFree(depthEnd);CHKERRQ(ierr);
237   PetscFunctionReturn(0);
238 }
239 
240 #undef __FUNCT__
241 #define __FUNCT__ "DMPlexShiftSF_Internal"
242 static PetscErrorCode DMPlexShiftSF_Internal(DM dm, PetscInt depthShift[], DM dmNew)
243 {
244   PetscInt          *depthEnd;
245   PetscInt           depth = 0, d;
246   PetscSF            sfPoint, sfPointNew;
247   const PetscSFNode *remotePoints;
248   PetscSFNode       *gremotePoints;
249   const PetscInt    *localPoints;
250   PetscInt          *glocalPoints, *newLocation, *newRemoteLocation;
251   PetscInt           numRoots, numLeaves, l, pStart, pEnd, totShift = 0;
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 = DMGetPointSF(dm, &sfPoint);CHKERRQ(ierr);
263   ierr = DMGetPointSF(dmNew, &sfPointNew);CHKERRQ(ierr);
264   ierr = DMPlexGetChart(dm, &pStart, &pEnd);CHKERRQ(ierr);
265   ierr = PetscSFGetGraph(sfPoint, &numRoots, &numLeaves, &localPoints, &remotePoints);CHKERRQ(ierr);
266   if (numRoots >= 0) {
267     ierr = PetscMalloc2(numRoots,PetscInt,&newLocation,pEnd-pStart,PetscInt,&newRemoteLocation);CHKERRQ(ierr);
268     for (l=0; l<numRoots; l++) newLocation[l] = DMPlexShiftPoint_Internal(l, depth, depthEnd, depthShift);
269     ierr = PetscSFBcastBegin(sfPoint, MPIU_INT, newLocation, newRemoteLocation);CHKERRQ(ierr);
270     ierr = PetscSFBcastEnd(sfPoint, MPIU_INT, newLocation, newRemoteLocation);CHKERRQ(ierr);
271     ierr = PetscMalloc(numLeaves * sizeof(PetscInt),    &glocalPoints);CHKERRQ(ierr);
272     ierr = PetscMalloc(numLeaves * sizeof(PetscSFNode), &gremotePoints);CHKERRQ(ierr);
273     for (l = 0; l < numLeaves; ++l) {
274       glocalPoints[l]        = DMPlexShiftPoint_Internal(localPoints[l], depth, depthEnd, depthShift);
275       gremotePoints[l].rank  = remotePoints[l].rank;
276       gremotePoints[l].index = newRemoteLocation[localPoints[l]];
277     }
278     ierr = PetscFree2(newLocation,newRemoteLocation);CHKERRQ(ierr);
279     ierr = PetscSFSetGraph(sfPointNew, numRoots + totShift, numLeaves, glocalPoints, PETSC_OWN_POINTER, gremotePoints, PETSC_OWN_POINTER);CHKERRQ(ierr);
280   }
281   ierr = PetscFree(depthEnd);CHKERRQ(ierr);
282   PetscFunctionReturn(0);
283 }
284 
285 #undef __FUNCT__
286 #define __FUNCT__ "DMPlexShiftLabels_Internal"
287 static PetscErrorCode DMPlexShiftLabels_Internal(DM dm, PetscInt depthShift[], DM dmNew)
288 {
289   PetscSF            sfPoint;
290   DMLabel            vtkLabel, ghostLabel;
291   PetscInt          *depthEnd;
292   const PetscSFNode *leafRemote;
293   const PetscInt    *leafLocal;
294   PetscInt           depth = 0, d, numLeaves, numLabels, l, cStart, cEnd, c, fStart, fEnd, f;
295   PetscMPIInt        rank;
296   PetscErrorCode     ierr;
297 
298   PetscFunctionBegin;
299   ierr = DMPlexGetDepth(dm, &depth);CHKERRQ(ierr);
300   ierr = PetscMalloc((depth+1) * sizeof(PetscInt), &depthEnd);CHKERRQ(ierr);
301   for (d = 0; d <= depth; ++d) {
302     ierr = DMPlexGetDepthStratum(dm, d, NULL, &depthEnd[d]);CHKERRQ(ierr);
303   }
304   /* Step 10: Convert labels */
305   ierr = DMPlexGetNumLabels(dm, &numLabels);CHKERRQ(ierr);
306   for (l = 0; l < numLabels; ++l) {
307     DMLabel         label, newlabel;
308     const char     *lname;
309     PetscBool       isDepth;
310     IS              valueIS;
311     const PetscInt *values;
312     PetscInt        numValues, val;
313 
314     ierr = DMPlexGetLabelName(dm, l, &lname);CHKERRQ(ierr);
315     ierr = PetscStrcmp(lname, "depth", &isDepth);CHKERRQ(ierr);
316     if (isDepth) continue;
317     ierr = DMPlexCreateLabel(dmNew, lname);CHKERRQ(ierr);
318     ierr = DMPlexGetLabel(dm, lname, &label);CHKERRQ(ierr);
319     ierr = DMPlexGetLabel(dmNew, lname, &newlabel);CHKERRQ(ierr);
320     ierr = DMLabelGetValueIS(label, &valueIS);CHKERRQ(ierr);
321     ierr = ISGetLocalSize(valueIS, &numValues);CHKERRQ(ierr);
322     ierr = ISGetIndices(valueIS, &values);CHKERRQ(ierr);
323     for (val = 0; val < numValues; ++val) {
324       IS              pointIS;
325       const PetscInt *points;
326       PetscInt        numPoints, p;
327 
328       ierr = DMLabelGetStratumIS(label, values[val], &pointIS);CHKERRQ(ierr);
329       ierr = ISGetLocalSize(pointIS, &numPoints);CHKERRQ(ierr);
330       ierr = ISGetIndices(pointIS, &points);CHKERRQ(ierr);
331       for (p = 0; p < numPoints; ++p) {
332         const PetscInt newpoint = DMPlexShiftPoint_Internal(points[p], depth, depthEnd, depthShift);
333 
334         ierr = DMLabelSetValue(newlabel, newpoint, values[val]);CHKERRQ(ierr);
335       }
336       ierr = ISRestoreIndices(pointIS, &points);CHKERRQ(ierr);
337       ierr = ISDestroy(&pointIS);CHKERRQ(ierr);
338     }
339     ierr = ISRestoreIndices(valueIS, &values);CHKERRQ(ierr);
340     ierr = ISDestroy(&valueIS);CHKERRQ(ierr);
341   }
342   ierr = PetscFree(depthEnd);CHKERRQ(ierr);
343   /* Step 11: Make label for output (vtk) and to mark ghost points (ghost) */
344   ierr = MPI_Comm_rank(PetscObjectComm((PetscObject)dm), &rank);CHKERRQ(ierr);
345   ierr = DMGetPointSF(dm, &sfPoint);CHKERRQ(ierr);
346   ierr = DMPlexGetHeightStratum(dm, 0, &cStart, &cEnd);CHKERRQ(ierr);
347   ierr = PetscSFGetGraph(sfPoint, NULL, &numLeaves, &leafLocal, &leafRemote);CHKERRQ(ierr);
348   ierr = DMPlexCreateLabel(dmNew, "vtk");CHKERRQ(ierr);
349   ierr = DMPlexCreateLabel(dmNew, "ghost");CHKERRQ(ierr);
350   ierr = DMPlexGetLabel(dmNew, "vtk", &vtkLabel);CHKERRQ(ierr);
351   ierr = DMPlexGetLabel(dmNew, "ghost", &ghostLabel);CHKERRQ(ierr);
352   for (l = 0, c = cStart; l < numLeaves && c < cEnd; ++l, ++c) {
353     for (; c < leafLocal[l] && c < cEnd; ++c) {
354       ierr = DMLabelSetValue(vtkLabel, c, 1);CHKERRQ(ierr);
355     }
356     if (leafLocal[l] >= cEnd) break;
357     if (leafRemote[l].rank == rank) {
358       ierr = DMLabelSetValue(vtkLabel, c, 1);CHKERRQ(ierr);
359     } else {
360       ierr = DMLabelSetValue(ghostLabel, c, 2);CHKERRQ(ierr);
361     }
362   }
363   for (; c < cEnd; ++c) {
364     ierr = DMLabelSetValue(vtkLabel, c, 1);CHKERRQ(ierr);
365   }
366   if (0) {
367     ierr = PetscViewerASCIISynchronizedAllow(PETSC_VIEWER_STDOUT_WORLD, PETSC_TRUE);CHKERRQ(ierr);
368     ierr = DMLabelView(vtkLabel, PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
369     ierr = PetscViewerFlush(PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
370   }
371   ierr = DMPlexGetHeightStratum(dmNew, 1, &fStart, &fEnd);CHKERRQ(ierr);
372   for (f = fStart; f < fEnd; ++f) {
373     PetscInt numCells;
374 
375     ierr = DMPlexGetSupportSize(dmNew, f, &numCells);CHKERRQ(ierr);
376     if (numCells < 2) {
377       ierr = DMLabelSetValue(ghostLabel, f, 1);CHKERRQ(ierr);
378     } else {
379       const PetscInt *cells = NULL;
380       PetscInt        vA, vB;
381 
382       ierr = DMPlexGetSupport(dmNew, f, &cells);CHKERRQ(ierr);
383       ierr = DMLabelGetValue(vtkLabel, cells[0], &vA);CHKERRQ(ierr);
384       ierr = DMLabelGetValue(vtkLabel, cells[1], &vB);CHKERRQ(ierr);
385       if (!vA && !vB) {ierr = DMLabelSetValue(ghostLabel, f, 1);CHKERRQ(ierr);}
386     }
387   }
388   if (0) {
389     ierr = PetscViewerASCIISynchronizedAllow(PETSC_VIEWER_STDOUT_WORLD, PETSC_TRUE);CHKERRQ(ierr);
390     ierr = DMLabelView(ghostLabel, PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
391     ierr = PetscViewerFlush(PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
392   }
393   PetscFunctionReturn(0);
394 }
395 
396 #undef __FUNCT__
397 #define __FUNCT__ "DMPlexConstructGhostCells_Internal"
398 static PetscErrorCode DMPlexConstructGhostCells_Internal(DM dm, DMLabel label, PetscInt *numGhostCells, DM gdm)
399 {
400   IS              valueIS;
401   const PetscInt *values;
402   PetscInt       *depthShift;
403   PetscInt        depth = 0, numFS, fs, ghostCell, cEnd, c;
404   PetscErrorCode  ierr;
405 
406   PetscFunctionBegin;
407   /* Count ghost cells */
408   ierr = DMLabelGetValueIS(label, &valueIS);CHKERRQ(ierr);
409   ierr = ISGetLocalSize(valueIS, &numFS);CHKERRQ(ierr);
410   ierr = ISGetIndices(valueIS, &values);CHKERRQ(ierr);
411 
412   *numGhostCells = 0;
413   for (fs = 0; fs < numFS; ++fs) {
414     PetscInt numBdFaces;
415 
416     ierr = DMLabelGetStratumSize(label, values[fs], &numBdFaces);CHKERRQ(ierr);
417 
418     *numGhostCells += numBdFaces;
419   }
420   ierr = DMPlexGetDepth(dm, &depth);CHKERRQ(ierr);
421   ierr = PetscMalloc((depth+1) * sizeof(PetscInt), &depthShift);CHKERRQ(ierr);
422   ierr = PetscMemzero(depthShift, (depth+1) * sizeof(PetscInt));CHKERRQ(ierr);
423   if (depth >= 0) depthShift[depth] = *numGhostCells;
424   ierr = DMPlexShiftSizes_Internal(dm, depthShift, gdm);CHKERRQ(ierr);
425   /* Step 3: Set cone/support sizes for new points */
426   ierr = DMPlexGetHeightStratum(dm, 0, NULL, &cEnd);CHKERRQ(ierr);
427   for (c = cEnd; c < cEnd + *numGhostCells; ++c) {
428     ierr = DMPlexSetConeSize(gdm, c, 1);CHKERRQ(ierr);
429   }
430   for (fs = 0; fs < numFS; ++fs) {
431     IS              faceIS;
432     const PetscInt *faces;
433     PetscInt        numFaces, f;
434 
435     ierr = DMLabelGetStratumIS(label, values[fs], &faceIS);CHKERRQ(ierr);
436     ierr = ISGetLocalSize(faceIS, &numFaces);CHKERRQ(ierr);
437     ierr = ISGetIndices(faceIS, &faces);CHKERRQ(ierr);
438     for (f = 0; f < numFaces; ++f) {
439       PetscInt size;
440 
441       ierr = DMPlexGetSupportSize(dm, faces[f], &size);CHKERRQ(ierr);
442       if (size != 1) SETERRQ2(PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_WRONG, "DM has boundary face %d with %d support cells", faces[f], size);
443       ierr = DMPlexSetSupportSize(gdm, faces[f] + *numGhostCells, 2);CHKERRQ(ierr);
444     }
445     ierr = ISRestoreIndices(faceIS, &faces);CHKERRQ(ierr);
446     ierr = ISDestroy(&faceIS);CHKERRQ(ierr);
447   }
448   /* Step 4: Setup ghosted DM */
449   ierr = DMSetUp(gdm);CHKERRQ(ierr);
450   ierr = DMPlexShiftPoints_Internal(dm, depthShift, gdm);CHKERRQ(ierr);
451   /* Step 6: Set cones and supports for new points */
452   ghostCell = cEnd;
453   for (fs = 0; fs < numFS; ++fs) {
454     IS              faceIS;
455     const PetscInt *faces;
456     PetscInt        numFaces, f;
457 
458     ierr = DMLabelGetStratumIS(label, values[fs], &faceIS);CHKERRQ(ierr);
459     ierr = ISGetLocalSize(faceIS, &numFaces);CHKERRQ(ierr);
460     ierr = ISGetIndices(faceIS, &faces);CHKERRQ(ierr);
461     for (f = 0; f < numFaces; ++f, ++ghostCell) {
462       PetscInt newFace = faces[f] + *numGhostCells;
463 
464       ierr = DMPlexSetCone(gdm, ghostCell, &newFace);CHKERRQ(ierr);
465       ierr = DMPlexInsertSupport(gdm, newFace, 1, ghostCell);CHKERRQ(ierr);
466     }
467     ierr = ISRestoreIndices(faceIS, &faces);CHKERRQ(ierr);
468     ierr = ISDestroy(&faceIS);CHKERRQ(ierr);
469   }
470   ierr = ISRestoreIndices(valueIS, &values);CHKERRQ(ierr);
471   ierr = ISDestroy(&valueIS);CHKERRQ(ierr);
472   /* Step 7: Stratify */
473   ierr = DMPlexStratify(gdm);CHKERRQ(ierr);
474   ierr = DMPlexShiftCoordinates_Internal(dm, depthShift, gdm);CHKERRQ(ierr);
475   ierr = DMPlexShiftSF_Internal(dm, depthShift, gdm);CHKERRQ(ierr);
476   ierr = DMPlexShiftLabels_Internal(dm, depthShift, gdm);CHKERRQ(ierr);
477   ierr = PetscFree(depthShift);CHKERRQ(ierr);
478   PetscFunctionReturn(0);
479 }
480 
481 #undef __FUNCT__
482 #define __FUNCT__ "DMPlexConstructGhostCells"
483 /*@C
484   DMPlexConstructGhostCells - Construct ghost cells which connect to every boundary face
485 
486   Collective on dm
487 
488   Input Parameters:
489 + dm - The original DM
490 - labelName - The label specifying the boundary faces, or "Face Sets" if this is NULL
491 
492   Output Parameters:
493 + numGhostCells - The number of ghost cells added to the DM
494 - dmGhosted - The new DM
495 
496   Note: If no label exists of that name, one will be created marking all boundary faces
497 
498   Level: developer
499 
500 .seealso: DMCreate()
501 */
502 PetscErrorCode DMPlexConstructGhostCells(DM dm, const char labelName[], PetscInt *numGhostCells, DM *dmGhosted)
503 {
504   DM             gdm;
505   DMLabel        label;
506   const char    *name = labelName ? labelName : "Face Sets";
507   PetscInt       dim;
508   PetscErrorCode ierr;
509 
510   PetscFunctionBegin;
511   PetscValidHeaderSpecific(dm, DM_CLASSID, 1);
512   PetscValidPointer(numGhostCells, 3);
513   PetscValidPointer(dmGhosted, 4);
514   ierr = DMCreate(PetscObjectComm((PetscObject)dm), &gdm);CHKERRQ(ierr);
515   ierr = DMSetType(gdm, DMPLEX);CHKERRQ(ierr);
516   ierr = DMPlexGetDimension(dm, &dim);CHKERRQ(ierr);
517   ierr = DMPlexSetDimension(gdm, dim);CHKERRQ(ierr);
518   ierr = DMPlexGetLabel(dm, name, &label);CHKERRQ(ierr);
519   if (!label) {
520     /* Get label for boundary faces */
521     ierr = DMPlexCreateLabel(dm, name);CHKERRQ(ierr);
522     ierr = DMPlexGetLabel(dm, name, &label);CHKERRQ(ierr);
523     ierr = DMPlexMarkBoundaryFaces(dm, label);CHKERRQ(ierr);
524   }
525   ierr = DMPlexConstructGhostCells_Internal(dm, label, numGhostCells, gdm);CHKERRQ(ierr);
526   ierr = DMSetFromOptions(gdm);CHKERRQ(ierr);
527   *dmGhosted = gdm;
528   PetscFunctionReturn(0);
529 }
530 
531 #undef __FUNCT__
532 #define __FUNCT__ "DMPlexConstructCohesiveCells_Internal"
533 /*
534   We are adding two kinds of points here:
535     Replicated: Copies of points which exist in the mesh, such as vertices identified across a fault
536     Hybrid:     Entirely new points, such as cohesive cells
537 */
538 static PetscErrorCode DMPlexConstructCohesiveCells_Internal(DM dm, DMLabel label, DM sdm)
539 {
540   MPI_Comm         comm;
541   IS               valueIS;
542   PetscInt         numSP = 0;       /* The number of depths for which we have replicated points */
543   const PetscInt  *values;          /* List of depths for which we have replicated points */
544   IS              *pointIS;
545   PetscInt        *numSplitPoints;  /* The number of replicated points at each depth */
546   PetscInt        *numHybridPoints; /* The number of hybrid points at each depth */
547   const PetscInt **splitPoints;     /* Replicated points for each depth */
548   PetscSection     coordSection;
549   Vec              coordinates;
550   PetscScalar     *coords;
551   PetscInt         depths[4];       /* Depths in the order that plex points are numbered */
552   PetscInt        *depthShift;      /* Number of replicated+hybrid points at each depth */
553   PetscInt        *depthOffset;     /* Prefix sums of depthShift */
554   PetscInt        *pMaxNew;         /* The first replicated point at each depth in the new mesh, hybrids come after this */
555   PetscInt        *coneNew, *coneONew, *supportNew;
556   PetscInt         shift = 100, depth = 0, dep, dim, d, sp, maxConeSize, maxSupportSize, numLabels, vStart, vEnd, pEnd, p, v;
557   PetscErrorCode   ierr;
558 
559   PetscFunctionBegin;
560   ierr = PetscObjectGetComm((PetscObject)dm,&comm);CHKERRQ(ierr);
561   ierr = DMPlexGetDimension(dm, &dim);CHKERRQ(ierr);
562   ierr = DMPlexGetDepth(dm, &depth);CHKERRQ(ierr);
563   ierr = DMPlexGetDepthStratum(dm, 0, &vStart, &vEnd);CHKERRQ(ierr);
564   depths[0] = depth;
565   depths[1] = 0;
566   depths[2] = depth-1;
567   depths[3] = 1;
568   /* Count split points and add cohesive cells */
569   ierr = DMPlexGetMaxSizes(dm, &maxConeSize, &maxSupportSize);CHKERRQ(ierr);
570   ierr = PetscMalloc6(depth+1,PetscInt,&depthShift,depth+1,PetscInt,&depthOffset,depth+1,PetscInt,&pMaxNew,maxConeSize*3,PetscInt,&coneNew,maxConeSize*3,PetscInt,&coneONew,maxSupportSize,PetscInt,&supportNew);CHKERRQ(ierr);
571   ierr = PetscMalloc4(depth+1,IS,&pointIS,depth+1,PetscInt,&numSplitPoints,depth+1,PetscInt,&numHybridPoints,depth+1,const PetscInt*,&splitPoints);CHKERRQ(ierr);
572   ierr = PetscMemzero(depthShift,  (depth+1) * sizeof(PetscInt));CHKERRQ(ierr);
573   ierr = PetscMemzero(depthOffset, (depth+1) * sizeof(PetscInt));CHKERRQ(ierr);
574   for (d = 0; d <= depth; ++d) {
575     ierr               = DMPlexGetDepthStratum(dm, d, NULL, &pMaxNew[d]);CHKERRQ(ierr);
576     numSplitPoints[d]  = 0;
577     numHybridPoints[d] = 0;
578     splitPoints[d]     = NULL;
579     pointIS[d]         = NULL;
580   }
581   if (label) {
582     ierr = DMLabelGetValueIS(label, &valueIS);CHKERRQ(ierr);
583     ierr = ISGetLocalSize(valueIS, &numSP);CHKERRQ(ierr);
584     ierr = ISGetIndices(valueIS, &values);CHKERRQ(ierr);
585   }
586   for (sp = 0; sp < numSP; ++sp) {
587     const PetscInt dep = values[sp];
588 
589     if ((dep < 0) || (dep > depth)) continue;
590     ierr = DMLabelGetStratumIS(label, dep, &pointIS[dep]);CHKERRQ(ierr);
591     if (pointIS[dep]) {
592       ierr = ISGetLocalSize(pointIS[dep], &numSplitPoints[dep]);CHKERRQ(ierr);
593       ierr = ISGetIndices(pointIS[dep], &splitPoints[dep]);CHKERRQ(ierr);
594     }
595   }
596   /* Calculate number of hybrid points */
597   for (d = 1; d <= depth; ++d) numHybridPoints[d]     = numSplitPoints[d-1]; /* There is a hybrid cell/face/edge for every split face/edge/vertex   */
598   for (d = 0; d <= depth; ++d) depthShift[d]          = numSplitPoints[d] + numHybridPoints[d];
599   for (d = 1; d <= depth; ++d) depthOffset[depths[d]] = depthOffset[depths[d-1]] + depthShift[depths[d-1]];
600   for (d = 0; d <= depth; ++d) pMaxNew[d]            += depthOffset[d];
601   ierr = DMPlexShiftSizes_Internal(dm, depthShift, sdm);CHKERRQ(ierr);
602   /* Step 3: Set cone/support sizes for new points */
603   for (dep = 0; dep <= depth; ++dep) {
604     for (p = 0; p < numSplitPoints[dep]; ++p) {
605       const PetscInt  oldp   = splitPoints[dep][p];
606       const PetscInt  newp   = oldp + depthOffset[dep];
607       const PetscInt  splitp = p    + pMaxNew[dep];
608       const PetscInt *support;
609       PetscInt        coneSize, supportSize, qf, qn, qp, e;
610 
611       ierr = DMPlexGetConeSize(dm, oldp, &coneSize);CHKERRQ(ierr);
612       ierr = DMPlexSetConeSize(sdm, splitp, coneSize);CHKERRQ(ierr);
613       ierr = DMPlexGetSupportSize(dm, oldp, &supportSize);CHKERRQ(ierr);
614       ierr = DMPlexSetSupportSize(sdm, splitp, supportSize);CHKERRQ(ierr);
615       if (dep == depth-1) {
616         const PetscInt hybcell = p + pMaxNew[dep+1] + numSplitPoints[dep+1];
617 
618         /* Add cohesive cells, they are prisms */
619         ierr = DMPlexSetConeSize(sdm, hybcell, 2 + coneSize);CHKERRQ(ierr);
620       } else if (dep == 0) {
621         const PetscInt hybedge = p + pMaxNew[dep+1] + numSplitPoints[dep+1];
622 
623         ierr = DMPlexGetSupport(dm, oldp, &support);CHKERRQ(ierr);
624         for (e = 0, qn = 0, qp = 0, qf = 0; e < supportSize; ++e) {
625           PetscInt val;
626 
627           ierr = DMLabelGetValue(label, support[e], &val);CHKERRQ(ierr);
628           if (val == 1) ++qf;
629           if ((val == 1) || (val ==  (shift + 1))) ++qn;
630           if ((val == 1) || (val == -(shift + 1))) ++qp;
631         }
632         /* Split old vertex: Edges into original vertex and new cohesive edge */
633         ierr = DMPlexSetSupportSize(sdm, newp, qn+1);CHKERRQ(ierr);
634         /* Split new vertex: Edges into split vertex and new cohesive edge */
635         ierr = DMPlexSetSupportSize(sdm, splitp, qp+1);CHKERRQ(ierr);
636         /* Add hybrid edge */
637         ierr = DMPlexSetConeSize(sdm, hybedge, 2);CHKERRQ(ierr);
638         ierr = DMPlexSetSupportSize(sdm, hybedge, qf);CHKERRQ(ierr);
639       } else if (dep == dim-2) {
640         const PetscInt hybface = p + pMaxNew[dep+1] + numSplitPoints[dep+1];
641 
642         ierr = DMPlexGetSupport(dm, oldp, &support);CHKERRQ(ierr);
643         for (e = 0, qn = 0, qp = 0, qf = 0; e < supportSize; ++e) {
644           PetscInt val;
645 
646           ierr = DMLabelGetValue(label, support[e], &val);CHKERRQ(ierr);
647           if (val == dim-1) ++qf;
648           if ((val == dim-1) || (val ==  (shift + dim-1))) ++qn;
649           if ((val == dim-1) || (val == -(shift + dim-1))) ++qp;
650         }
651         /* Split old edge: Faces into original edge and cohesive face (positive side?) */
652         ierr = DMPlexSetSupportSize(sdm, newp, qn+1);CHKERRQ(ierr);
653         /* Split new edge: Faces into split edge and cohesive face (negative side?) */
654         ierr = DMPlexSetSupportSize(sdm, splitp, qp+1);CHKERRQ(ierr);
655         /* Add hybrid face */
656         ierr = DMPlexSetConeSize(sdm, hybface, 4);CHKERRQ(ierr);
657         ierr = DMPlexSetSupportSize(sdm, hybface, qf);CHKERRQ(ierr);
658       }
659     }
660   }
661   /* Step 4: Setup split DM */
662   ierr = DMSetUp(sdm);CHKERRQ(ierr);
663   ierr = DMPlexShiftPoints_Internal(dm, depthShift, sdm);CHKERRQ(ierr);
664   /* Step 6: Set cones and supports for new points */
665   for (dep = 0; dep <= depth; ++dep) {
666     for (p = 0; p < numSplitPoints[dep]; ++p) {
667       const PetscInt  oldp   = splitPoints[dep][p];
668       const PetscInt  newp   = oldp + depthOffset[dep];
669       const PetscInt  splitp = p    + pMaxNew[dep];
670       const PetscInt *cone, *support, *ornt;
671       PetscInt        coneSize, supportSize, q, qf, qn, qp, v, e, s;
672 
673       ierr = DMPlexGetConeSize(dm, oldp, &coneSize);CHKERRQ(ierr);
674       ierr = DMPlexGetCone(dm, oldp, &cone);CHKERRQ(ierr);
675       ierr = DMPlexGetConeOrientation(dm, oldp, &ornt);CHKERRQ(ierr);
676       ierr = DMPlexGetSupportSize(dm, oldp, &supportSize);CHKERRQ(ierr);
677       ierr = DMPlexGetSupport(dm, oldp, &support);CHKERRQ(ierr);
678       if (dep == depth-1) {
679         const PetscInt  hybcell = p + pMaxNew[dep+1] + numSplitPoints[dep+1];
680         const PetscInt *supportF;
681 
682         /* Split face:       copy in old face to new face to start */
683         ierr = DMPlexGetSupport(sdm, newp,  &supportF);CHKERRQ(ierr);
684         ierr = DMPlexSetSupport(sdm, splitp, supportF);CHKERRQ(ierr);
685         /* Split old face:   old vertices/edges in cone so no change */
686         /* Split new face:   new vertices/edges in cone */
687         for (q = 0; q < coneSize; ++q) {
688           ierr = PetscFindInt(cone[q], numSplitPoints[dep-1], splitPoints[dep-1], &v);CHKERRQ(ierr);
689 
690           coneNew[2+q] = v + pMaxNew[dep-1];
691         }
692         ierr = DMPlexSetCone(sdm, splitp, &coneNew[2]);CHKERRQ(ierr);
693         ierr = DMPlexSetConeOrientation(sdm, splitp, ornt);CHKERRQ(ierr);
694         /* Face support */
695         for (s = 0; s < supportSize; ++s) {
696           PetscInt val;
697 
698           ierr = DMLabelGetValue(label, support[s], &val);CHKERRQ(ierr);
699           if (val < 0) {
700             /* Split old face:   Replace negative side cell with cohesive cell */
701              ierr = DMPlexInsertSupport(sdm, newp, s, hybcell);CHKERRQ(ierr);
702           } else {
703             /* Split new face:   Replace positive side cell with cohesive cell */
704             ierr = DMPlexInsertSupport(sdm, splitp, s, hybcell);CHKERRQ(ierr);
705             /* Get orientation for cohesive face */
706             {
707               const PetscInt *ncone, *nconeO;
708               PetscInt        nconeSize, nc;
709 
710               ierr = DMPlexGetConeSize(dm, support[s], &nconeSize);CHKERRQ(ierr);
711               ierr = DMPlexGetCone(dm, support[s], &ncone);CHKERRQ(ierr);
712               ierr = DMPlexGetConeOrientation(dm, support[s], &nconeO);CHKERRQ(ierr);
713               for (nc = 0; nc < nconeSize; ++nc) {
714                 if (ncone[nc] == oldp) {
715                   coneONew[0] = nconeO[nc];
716                   break;
717                 }
718               }
719               if (nc >= nconeSize) SETERRQ2(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Could not locate face %d in neighboring cell %d", oldp, support[s]);
720             }
721           }
722         }
723         /* Cohesive cell:    Old and new split face, then new cohesive faces */
724         coneNew[0]  = newp;   /* Extracted negative side orientation above */
725         coneNew[1]  = splitp;
726         coneONew[1] = coneONew[0];
727         for (q = 0; q < coneSize; ++q) {
728           coneNew[2+q] += (pMaxNew[dep] - pMaxNew[dep-1]) + numSplitPoints[dep];
729           coneONew[2+q] = 0;
730         }
731         ierr = DMPlexSetCone(sdm, hybcell, coneNew);CHKERRQ(ierr);
732         ierr = DMPlexSetConeOrientation(sdm, hybcell, coneONew);CHKERRQ(ierr);
733       } else if (dep == 0) {
734         const PetscInt hybedge = p + pMaxNew[dep+1] + numSplitPoints[dep+1];
735 
736         /* Split old vertex: Edges in old split faces and new cohesive edge */
737         for (e = 0, qn = 0; e < supportSize; ++e) {
738           PetscInt val;
739 
740           ierr = DMLabelGetValue(label, support[e], &val);CHKERRQ(ierr);
741           if ((val == 1) || (val == (shift + 1))) {
742             supportNew[qn++] = support[e] + depthOffset[dep+1];
743           }
744         }
745         supportNew[qn] = hybedge;
746         ierr = DMPlexSetSupport(sdm, newp, supportNew);CHKERRQ(ierr);
747         /* Split new vertex: Edges in new split faces and new cohesive edge */
748         for (e = 0, qp = 0; e < supportSize; ++e) {
749           PetscInt val, edge;
750 
751           ierr = DMLabelGetValue(label, support[e], &val);CHKERRQ(ierr);
752           if (val == 1) {
753             ierr = PetscFindInt(support[e], numSplitPoints[dep+1], splitPoints[dep+1], &edge);CHKERRQ(ierr);
754             if (edge < 0) SETERRQ1(comm, PETSC_ERR_ARG_WRONG, "Edge %d is not a split edge", support[e]);
755             supportNew[qp++] = edge + pMaxNew[dep+1];
756           } else if (val == -(shift + 1)) {
757             supportNew[qp++] = support[e] + depthOffset[dep+1];
758           }
759         }
760         supportNew[qp] = hybedge;
761         ierr = DMPlexSetSupport(sdm, splitp, supportNew);CHKERRQ(ierr);
762         /* Hybrid edge:    Old and new split vertex */
763         coneNew[0] = newp;
764         coneNew[1] = splitp;
765         ierr = DMPlexSetCone(sdm, hybedge, coneNew);CHKERRQ(ierr);
766         for (e = 0, qf = 0; e < supportSize; ++e) {
767           PetscInt val, edge;
768 
769           ierr = DMLabelGetValue(label, support[e], &val);CHKERRQ(ierr);
770           if (val == 1) {
771             ierr = PetscFindInt(support[e], numSplitPoints[dep+1], splitPoints[dep+1], &edge);CHKERRQ(ierr);
772             if (edge < 0) SETERRQ1(comm, PETSC_ERR_ARG_WRONG, "Edge %d is not a split edge", support[e]);
773             supportNew[qf++] = edge + pMaxNew[dep+2] + numSplitPoints[dep+2];
774           }
775         }
776         ierr = DMPlexSetSupport(sdm, hybedge, supportNew);CHKERRQ(ierr);
777       } else if (dep == dim-2) {
778         const PetscInt hybface = p + pMaxNew[dep+1] + numSplitPoints[dep+1];
779 
780         /* Split old edge:   old vertices in cone so no change */
781         /* Split new edge:   new vertices in cone */
782         for (q = 0; q < coneSize; ++q) {
783           ierr = PetscFindInt(cone[q], numSplitPoints[dep-1], splitPoints[dep-1], &v);CHKERRQ(ierr);
784 
785           coneNew[q] = v + pMaxNew[dep-1];
786         }
787         ierr = DMPlexSetCone(sdm, splitp, coneNew);CHKERRQ(ierr);
788         /* Split old edge: Faces in positive side cells and old split faces */
789         for (e = 0, q = 0; e < supportSize; ++e) {
790           PetscInt val;
791 
792           ierr = DMLabelGetValue(label, support[e], &val);CHKERRQ(ierr);
793           if (val == dim-1) {
794             supportNew[q++] = support[e] + depthOffset[dep+1];
795           } else if (val == (shift + dim-1)) {
796             supportNew[q++] = support[e] + depthOffset[dep+1];
797           }
798         }
799         supportNew[q++] = p + pMaxNew[dep+1] + numSplitPoints[dep+1];
800         ierr = DMPlexSetSupport(sdm, newp, supportNew);CHKERRQ(ierr);
801         /* Split new edge: Faces in negative side cells and new split faces */
802         for (e = 0, q = 0; e < supportSize; ++e) {
803           PetscInt val, face;
804 
805           ierr = DMLabelGetValue(label, support[e], &val);CHKERRQ(ierr);
806           if (val == dim-1) {
807             ierr = PetscFindInt(support[e], numSplitPoints[dep+1], splitPoints[dep+1], &face);CHKERRQ(ierr);
808             if (face < 0) SETERRQ1(comm, PETSC_ERR_ARG_WRONG, "Face %d is not a split face", support[e]);
809             supportNew[q++] = face + pMaxNew[dep+1];
810           } else if (val == -(shift + dim-1)) {
811             supportNew[q++] = support[e] + depthOffset[dep+1];
812           }
813         }
814         supportNew[q++] = p + pMaxNew[dep+1] + numSplitPoints[dep+1];
815         ierr = DMPlexSetSupport(sdm, splitp, supportNew);CHKERRQ(ierr);
816         /* Hybrid face */
817         coneNew[0] = newp;
818         coneNew[1] = splitp;
819         for (v = 0; v < coneSize; ++v) {
820           PetscInt vertex;
821           ierr = PetscFindInt(cone[v], numSplitPoints[dep-1], splitPoints[dep-1], &vertex);CHKERRQ(ierr);
822           if (vertex < 0) SETERRQ1(comm, PETSC_ERR_ARG_WRONG, "Vertex %d is not a split vertex", support[e]);
823           coneNew[2+v] = vertex + pMaxNew[dep] + numSplitPoints[dep];
824         }
825         ierr = DMPlexSetCone(sdm, hybface, coneNew);CHKERRQ(ierr);
826         for (e = 0, qf = 0; e < supportSize; ++e) {
827           PetscInt val, face;
828 
829           ierr = DMLabelGetValue(label, support[e], &val);CHKERRQ(ierr);
830           if (val == dim-1) {
831             ierr = PetscFindInt(support[e], numSplitPoints[dep+1], splitPoints[dep+1], &face);CHKERRQ(ierr);
832             if (face < 0) SETERRQ1(comm, PETSC_ERR_ARG_WRONG, "Face %d is not a split face", support[e]);
833             supportNew[qf++] = face + pMaxNew[dep+2] + numSplitPoints[dep+2];
834           }
835         }
836         ierr = DMPlexSetSupport(sdm, hybface, supportNew);CHKERRQ(ierr);
837       }
838     }
839   }
840   /* Step 6b: Replace split points in negative side cones */
841   for (sp = 0; sp < numSP; ++sp) {
842     PetscInt        dep = values[sp];
843     IS              pIS;
844     PetscInt        numPoints;
845     const PetscInt *points;
846 
847     if (dep >= 0) continue;
848     ierr = DMLabelGetStratumIS(label, dep, &pIS);CHKERRQ(ierr);
849     if (!pIS) continue;
850     dep  = -dep - shift;
851     ierr = ISGetLocalSize(pIS, &numPoints);CHKERRQ(ierr);
852     ierr = ISGetIndices(pIS, &points);CHKERRQ(ierr);
853     for (p = 0; p < numPoints; ++p) {
854       const PetscInt  oldp = points[p];
855       const PetscInt  newp = depthOffset[dep] + oldp;
856       const PetscInt *cone;
857       PetscInt        coneSize, c;
858       /* PetscBool       replaced = PETSC_FALSE; */
859 
860       /* Negative edge: replace split vertex */
861       /* Negative cell: replace split face */
862       ierr = DMPlexGetConeSize(sdm, newp, &coneSize);CHKERRQ(ierr);
863       ierr = DMPlexGetCone(sdm, newp, &cone);CHKERRQ(ierr);
864       for (c = 0; c < coneSize; ++c) {
865         const PetscInt coldp = cone[c] - depthOffset[dep-1];
866         PetscInt       csplitp, cp, val;
867 
868         ierr = DMLabelGetValue(label, coldp, &val);CHKERRQ(ierr);
869         if (val == dep-1) {
870           ierr = PetscFindInt(coldp, numSplitPoints[dep-1], splitPoints[dep-1], &cp);CHKERRQ(ierr);
871           if (cp < 0) SETERRQ2(comm, PETSC_ERR_ARG_WRONG, "Point %d is not a split point of dimension %d", oldp, dep-1);
872           csplitp  = pMaxNew[dep-1] + cp;
873           ierr     = DMPlexInsertCone(sdm, newp, c, csplitp);CHKERRQ(ierr);
874           /* replaced = PETSC_TRUE; */
875         }
876       }
877       /* Cells with only a vertex or edge on the submesh have no replacement */
878       /* if (!replaced) SETERRQ1(comm, PETSC_ERR_ARG_WRONG, "The cone of point %d does not contain split points", oldp); */
879     }
880     ierr = ISRestoreIndices(pIS, &points);CHKERRQ(ierr);
881     ierr = ISDestroy(&pIS);CHKERRQ(ierr);
882   }
883   /* Step 7: Stratify */
884   ierr = DMPlexStratify(sdm);CHKERRQ(ierr);
885   /* Step 8: Coordinates */
886   ierr = DMPlexShiftCoordinates_Internal(dm, depthShift, sdm);CHKERRQ(ierr);
887   ierr = DMPlexGetCoordinateSection(sdm, &coordSection);CHKERRQ(ierr);
888   ierr = DMGetCoordinatesLocal(sdm, &coordinates);CHKERRQ(ierr);
889   ierr = VecGetArray(coordinates, &coords);CHKERRQ(ierr);
890   for (v = 0; v < (numSplitPoints ? numSplitPoints[0] : 0); ++v) {
891     const PetscInt newp   = depthOffset[0] + splitPoints[0][v];
892     const PetscInt splitp = pMaxNew[0] + v;
893     PetscInt       dof, off, soff, d;
894 
895     ierr = PetscSectionGetDof(coordSection, newp, &dof);CHKERRQ(ierr);
896     ierr = PetscSectionGetOffset(coordSection, newp, &off);CHKERRQ(ierr);
897     ierr = PetscSectionGetOffset(coordSection, splitp, &soff);CHKERRQ(ierr);
898     for (d = 0; d < dof; ++d) coords[soff+d] = coords[off+d];
899   }
900   ierr = VecRestoreArray(coordinates, &coords);CHKERRQ(ierr);
901   /* Step 9: SF, if I can figure this out we can split the mesh in parallel */
902   ierr = DMPlexShiftSF_Internal(dm, depthShift, sdm);CHKERRQ(ierr);
903   /* Step 10: Labels */
904   ierr = DMPlexShiftLabels_Internal(dm, depthShift, sdm);CHKERRQ(ierr);
905   ierr = DMPlexGetNumLabels(sdm, &numLabels);CHKERRQ(ierr);
906   for (dep = 0; dep <= depth; ++dep) {
907     for (p = 0; p < numSplitPoints[dep]; ++p) {
908       const PetscInt newp   = depthOffset[dep] + splitPoints[dep][p];
909       const PetscInt splitp = pMaxNew[dep] + p;
910       PetscInt       l;
911 
912       for (l = 0; l < numLabels; ++l) {
913         DMLabel     mlabel;
914         const char *lname;
915         PetscInt    val;
916         PetscBool   isDepth;
917 
918         ierr = DMPlexGetLabelName(sdm, l, &lname);CHKERRQ(ierr);
919         ierr = PetscStrcmp(lname, "depth", &isDepth);CHKERRQ(ierr);
920         if (isDepth) continue;
921         ierr = DMPlexGetLabel(sdm, lname, &mlabel);CHKERRQ(ierr);
922         ierr = DMLabelGetValue(mlabel, newp, &val);CHKERRQ(ierr);
923         if (val >= 0) {
924           ierr = DMLabelSetValue(mlabel, splitp, val);CHKERRQ(ierr);
925 #if 0
926           /* Do not put cohesive edges into the label */
927           if (dep == 0) {
928             const PetscInt cedge = p + pMaxNew[dep+1] + numSplitPoints[dep+1];
929             ierr = DMLabelSetValue(mlabel, cedge, val);CHKERRQ(ierr);
930           } else if (dep == dim-2) {
931             const PetscInt cface = p + pMaxNew[dep+1] + numSplitPoints[dep+1];
932             ierr = DMLabelSetValue(mlabel, cface, val);CHKERRQ(ierr);
933           }
934           /* Do not put cohesive faces into the label */
935 #endif
936         }
937       }
938     }
939   }
940   for (sp = 0; sp < numSP; ++sp) {
941     const PetscInt dep = values[sp];
942 
943     if ((dep < 0) || (dep > depth)) continue;
944     if (pointIS[dep]) {ierr = ISRestoreIndices(pointIS[dep], &splitPoints[dep]);CHKERRQ(ierr);}
945     ierr = ISDestroy(&pointIS[dep]);CHKERRQ(ierr);
946   }
947   if (label) {
948     ierr = ISRestoreIndices(valueIS, &values);CHKERRQ(ierr);
949     ierr = ISDestroy(&valueIS);CHKERRQ(ierr);
950   }
951   for (d = 0; d <= depth; ++d) {
952     ierr = DMPlexGetDepthStratum(sdm, d, NULL, &pEnd);CHKERRQ(ierr);
953     pMaxNew[d] = pEnd - numHybridPoints[d];
954   }
955   ierr = DMPlexSetHybridBounds(sdm, depth >= 0 ? pMaxNew[depth] : PETSC_DETERMINE, depth>1 ? pMaxNew[depth-1] : PETSC_DETERMINE, depth>2 ? pMaxNew[1] : PETSC_DETERMINE, depth >= 0 ? pMaxNew[0] : PETSC_DETERMINE);CHKERRQ(ierr);
956   ierr = PetscFree6(depthShift, depthOffset, pMaxNew, coneNew, coneONew, supportNew);CHKERRQ(ierr);
957   ierr = PetscFree4(pointIS, numSplitPoints, numHybridPoints, splitPoints);CHKERRQ(ierr);
958   PetscFunctionReturn(0);
959 }
960 
961 #undef __FUNCT__
962 #define __FUNCT__ "DMPlexConstructCohesiveCells"
963 /*@C
964   DMPlexConstructCohesiveCells - Construct cohesive cells which split the face along an internal interface
965 
966   Collective on dm
967 
968   Input Parameters:
969 + dm - The original DM
970 - label - The label specifying the boundary faces (this could be auto-generated)
971 
972   Output Parameters:
973 - dmSplit - The new DM
974 
975   Level: developer
976 
977 .seealso: DMCreate(), DMPlexLabelCohesiveComplete()
978 @*/
979 PetscErrorCode DMPlexConstructCohesiveCells(DM dm, DMLabel label, DM *dmSplit)
980 {
981   DM             sdm;
982   PetscInt       dim;
983   PetscErrorCode ierr;
984 
985   PetscFunctionBegin;
986   PetscValidHeaderSpecific(dm, DM_CLASSID, 1);
987   PetscValidPointer(dmSplit, 3);
988   ierr = DMCreate(PetscObjectComm((PetscObject)dm), &sdm);CHKERRQ(ierr);
989   ierr = DMSetType(sdm, DMPLEX);CHKERRQ(ierr);
990   ierr = DMPlexGetDimension(dm, &dim);CHKERRQ(ierr);
991   ierr = DMPlexSetDimension(sdm, dim);CHKERRQ(ierr);
992   switch (dim) {
993   case 2:
994   case 3:
995     ierr = DMPlexConstructCohesiveCells_Internal(dm, label, sdm);CHKERRQ(ierr);
996     break;
997   default:
998     SETERRQ1(PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_OUTOFRANGE, "Cannot construct cohesive cells for dimension %d", dim);
999   }
1000   *dmSplit = sdm;
1001   PetscFunctionReturn(0);
1002 }
1003 
1004 #undef __FUNCT__
1005 #define __FUNCT__ "DMPlexLabelCohesiveComplete"
1006 /*@
1007   DMPlexLabelCohesiveComplete - Starting with a label marking vertices on an internal surface, we add all other mesh pieces
1008   to complete the surface
1009 
1010   Input Parameters:
1011 + dm - The DM
1012 . label - A DMLabel marking the surface vertices
1013 . flip  - Flag to flip the submesh normal and replace points on the other side
1014 - subdm - The subDM associated with the label, or NULL
1015 
1016   Output Parameter:
1017 . label - A DMLabel marking all surface points
1018 
1019   Level: developer
1020 
1021 .seealso: DMPlexConstructCohesiveCells(), DMPlexLabelComplete()
1022 @*/
1023 PetscErrorCode DMPlexLabelCohesiveComplete(DM dm, DMLabel label, PetscBool flip, DM subdm)
1024 {
1025   DMLabel         depthLabel;
1026   IS              dimIS, subpointIS;
1027   const PetscInt *points, *subpoints;
1028   const PetscInt  rev   = flip ? -1 : 1;
1029   PetscInt        shift = 100, dim, dep, cStart, cEnd, numPoints, numSubpoints, p, val;
1030   PetscErrorCode  ierr;
1031 
1032   PetscFunctionBegin;
1033   ierr = DMPlexGetDepthLabel(dm, &depthLabel);CHKERRQ(ierr);
1034   ierr = DMPlexGetDimension(dm, &dim);CHKERRQ(ierr);
1035   if (subdm) {
1036     ierr = DMPlexCreateSubpointIS(subdm, &subpointIS);CHKERRQ(ierr);
1037     if (subpointIS) {
1038       ierr = ISGetLocalSize(subpointIS, &numSubpoints);CHKERRQ(ierr);
1039       ierr = ISGetIndices(subpointIS, &subpoints);CHKERRQ(ierr);
1040     }
1041   }
1042   /* Cell orientation for face gives the side of the fault */
1043   ierr = DMLabelGetStratumIS(label, dim-1, &dimIS);CHKERRQ(ierr);
1044   if (!dimIS) PetscFunctionReturn(0);
1045   ierr = ISGetLocalSize(dimIS, &numPoints);CHKERRQ(ierr);
1046   ierr = ISGetIndices(dimIS, &points);CHKERRQ(ierr);
1047   for (p = 0; p < numPoints; ++p) {
1048     const PetscInt *support;
1049     PetscInt        supportSize, s;
1050 
1051     ierr = DMPlexGetSupportSize(dm, points[p], &supportSize);CHKERRQ(ierr);
1052     if (supportSize != 2) SETERRQ2(PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_WRONG, "Split face %d has %d != 2 supports", points[p], supportSize);
1053     ierr = DMPlexGetSupport(dm, points[p], &support);CHKERRQ(ierr);
1054     for (s = 0; s < supportSize; ++s) {
1055       const PetscInt *cone, *ornt;
1056       PetscInt        coneSize, c;
1057       PetscBool       pos = PETSC_TRUE;
1058 
1059       ierr = DMPlexGetConeSize(dm, support[s], &coneSize);CHKERRQ(ierr);
1060       ierr = DMPlexGetCone(dm, support[s], &cone);CHKERRQ(ierr);
1061       ierr = DMPlexGetConeOrientation(dm, support[s], &ornt);CHKERRQ(ierr);
1062       for (c = 0; c < coneSize; ++c) {
1063         if (cone[c] == points[p]) {
1064           PetscInt o = ornt[c];
1065 
1066           if (subdm) {
1067             const PetscInt *subcone, *subornt;
1068             PetscInt        subpoint, subface, subconeSize, sc;
1069 
1070             ierr = PetscFindInt(support[s], numSubpoints, subpoints, &subpoint);CHKERRQ(ierr);
1071             ierr = PetscFindInt(points[p],  numSubpoints, subpoints, &subface);CHKERRQ(ierr);
1072             ierr = DMPlexGetConeSize(subdm, subpoint, &subconeSize);CHKERRQ(ierr);
1073             ierr = DMPlexGetCone(subdm, subpoint, &subcone);CHKERRQ(ierr);
1074             ierr = DMPlexGetConeOrientation(subdm, subpoint, &subornt);CHKERRQ(ierr);
1075             for (sc = 0; sc < subconeSize; ++sc) {
1076               if (subcone[sc] == subface) {
1077                 o = subornt[0];
1078                 break;
1079               }
1080             }
1081             if (sc >= subconeSize) SETERRQ2(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Could not find point %d in cone for subpoint %d", points[p], subpoint);
1082           }
1083           if (o >= 0) {
1084             ierr = DMLabelSetValue(label, support[s],  rev*(shift+dim));CHKERRQ(ierr);
1085             pos  = rev > 0 ? PETSC_TRUE : PETSC_FALSE;
1086           } else {
1087             ierr = DMLabelSetValue(label, support[s], -rev*(shift+dim));CHKERRQ(ierr);
1088             pos  = rev > 0 ? PETSC_FALSE : PETSC_TRUE;
1089           }
1090           break;
1091         }
1092       }
1093       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]);
1094       /* Put faces touching the fault in the label */
1095       for (c = 0; c < coneSize; ++c) {
1096         const PetscInt point = cone[c];
1097 
1098         ierr = DMLabelGetValue(label, point, &val);CHKERRQ(ierr);
1099         if (val == -1) {
1100           PetscInt *closure = NULL;
1101           PetscInt  closureSize, cl;
1102 
1103           ierr = DMPlexGetTransitiveClosure(dm, point, PETSC_TRUE, &closureSize, &closure);CHKERRQ(ierr);
1104           for (cl = 0; cl < closureSize*2; cl += 2) {
1105             const PetscInt clp = closure[cl];
1106 
1107             ierr = DMLabelGetValue(label, clp, &val);CHKERRQ(ierr);
1108             if ((val >= 0) && (val < dim-1)) {
1109               ierr = DMLabelSetValue(label, point, pos == PETSC_TRUE ? shift+dim-1 : -(shift+dim-1));CHKERRQ(ierr);
1110               break;
1111             }
1112           }
1113           ierr = DMPlexRestoreTransitiveClosure(dm, point, PETSC_TRUE, &closureSize, &closure);CHKERRQ(ierr);
1114         }
1115       }
1116     }
1117   }
1118   if (subdm) {
1119     if (subpointIS) {ierr = ISRestoreIndices(subpointIS, &subpoints);CHKERRQ(ierr);}
1120     ierr = ISDestroy(&subpointIS);CHKERRQ(ierr);
1121   }
1122   ierr = ISRestoreIndices(dimIS, &points);CHKERRQ(ierr);
1123   ierr = ISDestroy(&dimIS);CHKERRQ(ierr);
1124   /* Search for other cells/faces/edges connected to the fault by a vertex */
1125   ierr = DMPlexGetHeightStratum(dm, 0, &cStart, &cEnd);CHKERRQ(ierr);
1126   ierr = DMLabelGetStratumIS(label, 0, &dimIS);CHKERRQ(ierr);
1127   if (!dimIS) PetscFunctionReturn(0);
1128   ierr = ISGetLocalSize(dimIS, &numPoints);CHKERRQ(ierr);
1129   ierr = ISGetIndices(dimIS, &points);CHKERRQ(ierr);
1130   for (p = 0; p < numPoints; ++p) {
1131     PetscInt *star = NULL;
1132     PetscInt  starSize, s;
1133     PetscInt  again = 1;  /* 0: Finished 1: Keep iterating after a change 2: No change */
1134 
1135     /* First mark cells connected to the fault */
1136     ierr = DMPlexGetTransitiveClosure(dm, points[p], PETSC_FALSE, &starSize, &star);CHKERRQ(ierr);
1137     while (again) {
1138       if (again > 1) SETERRQ(PetscObjectComm((PetscObject)dm), PETSC_ERR_PLIB, "Could not classify all cells connected to the fault");
1139       again = 0;
1140       for (s = 0; s < starSize*2; s += 2) {
1141         const PetscInt  point = star[s];
1142         const PetscInt *cone;
1143         PetscInt        coneSize, c;
1144 
1145         if ((point < cStart) || (point >= cEnd)) continue;
1146         ierr = DMLabelGetValue(label, point, &val);CHKERRQ(ierr);
1147         if (val != -1) continue;
1148         again = 2;
1149         ierr  = DMPlexGetConeSize(dm, point, &coneSize);CHKERRQ(ierr);
1150         ierr  = DMPlexGetCone(dm, point, &cone);CHKERRQ(ierr);
1151         for (c = 0; c < coneSize; ++c) {
1152           ierr = DMLabelGetValue(label, cone[c], &val);CHKERRQ(ierr);
1153           if (val != -1) {
1154             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);
1155             if (val > 0) {
1156               ierr = DMLabelSetValue(label, point,   shift+dim);CHKERRQ(ierr);
1157             } else {
1158               ierr = DMLabelSetValue(label, point, -(shift+dim));CHKERRQ(ierr);
1159             }
1160             again = 1;
1161             break;
1162           }
1163         }
1164       }
1165     }
1166     /* Classify the rest by cell membership */
1167     for (s = 0; s < starSize*2; s += 2) {
1168       const PetscInt point = star[s];
1169 
1170       ierr = DMLabelGetValue(label, point, &val);CHKERRQ(ierr);
1171       if (val == -1) {
1172         PetscInt  *sstar = NULL;
1173         PetscInt   sstarSize, ss;
1174         PetscBool  marked = PETSC_FALSE;
1175 
1176         ierr = DMPlexGetTransitiveClosure(dm, point, PETSC_FALSE, &sstarSize, &sstar);CHKERRQ(ierr);
1177         for (ss = 0; ss < sstarSize*2; ss += 2) {
1178           const PetscInt spoint = sstar[ss];
1179 
1180           if ((spoint < cStart) || (spoint >= cEnd)) continue;
1181           ierr = DMLabelGetValue(label, spoint, &val);CHKERRQ(ierr);
1182           if (val == -1) SETERRQ2(PetscObjectComm((PetscObject)dm), PETSC_ERR_PLIB, "Cell %d in star of %d does not have a valid label", spoint, point);
1183           ierr = DMLabelGetValue(depthLabel, point, &dep);CHKERRQ(ierr);
1184           if (val > 0) {
1185             ierr = DMLabelSetValue(label, point,   shift+dep);CHKERRQ(ierr);
1186           } else {
1187             ierr = DMLabelSetValue(label, point, -(shift+dep));CHKERRQ(ierr);
1188           }
1189           marked = PETSC_TRUE;
1190           break;
1191         }
1192         ierr = DMPlexRestoreTransitiveClosure(dm, point, PETSC_FALSE, &sstarSize, &sstar);CHKERRQ(ierr);
1193         if (!marked) SETERRQ1(PetscObjectComm((PetscObject)dm), PETSC_ERR_PLIB, "Point %d could not be classified", point);
1194       }
1195     }
1196     ierr = DMPlexRestoreTransitiveClosure(dm, points[p], PETSC_FALSE, &starSize, &star);CHKERRQ(ierr);
1197   }
1198   ierr = ISRestoreIndices(dimIS, &points);CHKERRQ(ierr);
1199   ierr = ISDestroy(&dimIS);CHKERRQ(ierr);
1200   PetscFunctionReturn(0);
1201 }
1202 
1203 #undef __FUNCT__
1204 #define __FUNCT__ "DMPlexCreateHybridMesh"
1205 /*@C
1206   DMPlexCreateHybridMesh - Create a mesh with hybrid cells along an internal interface
1207 
1208   Collective on dm
1209 
1210   Input Parameters:
1211 + dm - The original DM
1212 - labelName - The label specifying the interface vertices
1213 
1214   Output Parameters:
1215 + hybridLabel - The label fully marking the interface
1216 - dmHybrid - The new DM
1217 
1218   Level: developer
1219 
1220 .seealso: DMPlexConstructCohesiveCells(), DMPlexLabelCohesiveComplete(), DMCreate()
1221 @*/
1222 PetscErrorCode DMPlexCreateHybridMesh(DM dm, DMLabel label, DMLabel *hybridLabel, DM *dmHybrid)
1223 {
1224   DM             idm;
1225   DMLabel        subpointMap, hlabel;
1226   PetscInt       dim;
1227   PetscErrorCode ierr;
1228 
1229   PetscFunctionBegin;
1230   PetscValidHeaderSpecific(dm, DM_CLASSID, 1);
1231   if (hybridLabel) PetscValidPointer(hybridLabel, 3);
1232   PetscValidPointer(dmHybrid, 4);
1233   ierr = DMPlexGetDimension(dm, &dim);CHKERRQ(ierr);
1234   ierr = DMPlexCreateSubmesh(dm, label, 1, &idm);CHKERRQ(ierr);
1235   ierr = DMPlexOrient(idm);CHKERRQ(ierr);
1236   ierr = DMPlexGetSubpointMap(idm, &subpointMap);CHKERRQ(ierr);
1237   ierr = DMLabelDuplicate(subpointMap, &hlabel);CHKERRQ(ierr);
1238   ierr = DMLabelClearStratum(hlabel, dim);CHKERRQ(ierr);
1239   ierr = DMPlexLabelCohesiveComplete(dm, hlabel, PETSC_FALSE, idm);CHKERRQ(ierr);
1240   ierr = DMDestroy(&idm);CHKERRQ(ierr);
1241   ierr = DMPlexConstructCohesiveCells(dm, hlabel, dmHybrid);CHKERRQ(ierr);
1242   if (hybridLabel) *hybridLabel = hlabel;
1243   PetscFunctionReturn(0);
1244 }
1245 
1246 #undef __FUNCT__
1247 #define __FUNCT__ "DMPlexMarkSubmesh_Uninterpolated"
1248 /* Here we need the explicit assumption that:
1249 
1250      For any marked cell, the marked vertices constitute a single face
1251 */
1252 static PetscErrorCode DMPlexMarkSubmesh_Uninterpolated(DM dm, DMLabel vertexLabel, PetscInt value, DMLabel subpointMap, PetscInt *numFaces, PetscInt *nFV, DM subdm)
1253 {
1254   IS               subvertexIS = NULL;
1255   const PetscInt  *subvertices;
1256   PetscInt        *pStart, *pEnd, *pMax, pSize;
1257   PetscInt         depth, dim, d, numSubVerticesInitial = 0, v;
1258   PetscErrorCode   ierr;
1259 
1260   PetscFunctionBegin;
1261   *numFaces = 0;
1262   *nFV      = 0;
1263   ierr = DMPlexGetDepth(dm, &depth);CHKERRQ(ierr);
1264   ierr = DMPlexGetDimension(dm, &dim);CHKERRQ(ierr);
1265   pSize = PetscMax(depth, dim) + 1;
1266   ierr = PetscMalloc3(pSize,PetscInt,&pStart,pSize,PetscInt,&pEnd,pSize,PetscInt,&pMax);CHKERRQ(ierr);
1267   ierr = DMPlexGetHybridBounds(dm, depth >= 0 ? &pMax[depth] : NULL, depth>1 ? &pMax[depth-1] : NULL, depth>2 ? &pMax[1] : NULL, &pMax[0]);CHKERRQ(ierr);
1268   for (d = 0; d <= depth; ++d) {
1269     ierr = DMPlexGetDepthStratum(dm, d, &pStart[d], &pEnd[d]);CHKERRQ(ierr);
1270     if (pMax[d] >= 0) pEnd[d] = PetscMin(pEnd[d], pMax[d]);
1271   }
1272   /* Loop over initial vertices and mark all faces in the collective star() */
1273   if (vertexLabel) {ierr = DMLabelGetStratumIS(vertexLabel, value, &subvertexIS);CHKERRQ(ierr);}
1274   if (subvertexIS) {
1275     ierr = ISGetSize(subvertexIS, &numSubVerticesInitial);CHKERRQ(ierr);
1276     ierr = ISGetIndices(subvertexIS, &subvertices);CHKERRQ(ierr);
1277   }
1278   for (v = 0; v < numSubVerticesInitial; ++v) {
1279     const PetscInt vertex = subvertices[v];
1280     PetscInt      *star   = NULL;
1281     PetscInt       starSize, s, numCells = 0, c;
1282 
1283     ierr = DMPlexGetTransitiveClosure(dm, vertex, PETSC_FALSE, &starSize, &star);CHKERRQ(ierr);
1284     for (s = 0; s < starSize*2; s += 2) {
1285       const PetscInt point = star[s];
1286       if ((point >= pStart[depth]) && (point < pEnd[depth])) star[numCells++] = point;
1287     }
1288     for (c = 0; c < numCells; ++c) {
1289       const PetscInt cell    = star[c];
1290       PetscInt      *closure = NULL;
1291       PetscInt       closureSize, cl;
1292       PetscInt       cellLoc, numCorners = 0, faceSize = 0;
1293 
1294       ierr = DMLabelGetValue(subpointMap, cell, &cellLoc);CHKERRQ(ierr);
1295       if (cellLoc == 2) continue;
1296       if (cellLoc >= 0) SETERRQ2(PetscObjectComm((PetscObject)dm), PETSC_ERR_PLIB, "Cell %d has dimension %d in the surface label", cell, cellLoc);
1297       ierr = DMPlexGetTransitiveClosure(dm, cell, PETSC_TRUE, &closureSize, &closure);CHKERRQ(ierr);
1298       for (cl = 0; cl < closureSize*2; cl += 2) {
1299         const PetscInt point = closure[cl];
1300         PetscInt       vertexLoc;
1301 
1302         if ((point >= pStart[0]) && (point < pEnd[0])) {
1303           ++numCorners;
1304           ierr = DMLabelGetValue(vertexLabel, point, &vertexLoc);CHKERRQ(ierr);
1305           if (vertexLoc == value) closure[faceSize++] = point;
1306         }
1307       }
1308       if (!(*nFV)) {ierr = DMPlexGetNumFaceVertices(dm, dim, numCorners, nFV);CHKERRQ(ierr);}
1309       if (faceSize > *nFV) SETERRQ1(PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_WRONG, "Invalid submesh: Too many vertices %d of an element on the surface", faceSize);
1310       if (faceSize == *nFV) {
1311         const PetscInt *cells = NULL;
1312         PetscInt        numCells, nc;
1313 
1314         ++(*numFaces);
1315         for (cl = 0; cl < faceSize; ++cl) {
1316           ierr = DMLabelSetValue(subpointMap, closure[cl], 0);CHKERRQ(ierr);
1317         }
1318         ierr = DMPlexGetJoin(dm, faceSize, closure, &numCells, &cells);CHKERRQ(ierr);
1319         for (nc = 0; nc < numCells; ++nc) {
1320           ierr = DMLabelSetValue(subpointMap, cells[nc], 2);CHKERRQ(ierr);
1321         }
1322         ierr = DMPlexRestoreJoin(dm, faceSize, closure, &numCells, &cells);CHKERRQ(ierr);
1323       }
1324       ierr = DMPlexRestoreTransitiveClosure(dm, cell, PETSC_TRUE, &closureSize, &closure);CHKERRQ(ierr);
1325     }
1326     ierr = DMPlexRestoreTransitiveClosure(dm, vertex, PETSC_FALSE, &starSize, &star);CHKERRQ(ierr);
1327   }
1328   if (subvertexIS) {
1329     ierr = ISRestoreIndices(subvertexIS, &subvertices);CHKERRQ(ierr);
1330   }
1331   ierr = ISDestroy(&subvertexIS);CHKERRQ(ierr);
1332   ierr = PetscFree3(pStart,pEnd,pMax);CHKERRQ(ierr);
1333   PetscFunctionReturn(0);
1334 }
1335 
1336 #undef __FUNCT__
1337 #define __FUNCT__ "DMPlexMarkSubmesh_Interpolated"
1338 static PetscErrorCode DMPlexMarkSubmesh_Interpolated(DM dm, DMLabel vertexLabel, PetscInt value, DMLabel subpointMap, DM subdm)
1339 {
1340   IS               subvertexIS;
1341   const PetscInt  *subvertices;
1342   PetscInt        *pStart, *pEnd, *pMax;
1343   PetscInt         dim, d, numSubVerticesInitial = 0, v;
1344   PetscErrorCode   ierr;
1345 
1346   PetscFunctionBegin;
1347   ierr = DMPlexGetDimension(dm, &dim);CHKERRQ(ierr);
1348   ierr = PetscMalloc3(dim+1,PetscInt,&pStart,dim+1,PetscInt,&pEnd,dim+1,PetscInt,&pMax);CHKERRQ(ierr);
1349   ierr = DMPlexGetHybridBounds(dm, &pMax[dim], dim>1 ? &pMax[dim-1] : NULL, dim > 2 ? &pMax[1] : NULL, &pMax[0]);CHKERRQ(ierr);
1350   for (d = 0; d <= dim; ++d) {
1351     ierr = DMPlexGetDepthStratum(dm, d, &pStart[d], &pEnd[d]);CHKERRQ(ierr);
1352     if (pMax[d] >= 0) pEnd[d] = PetscMin(pEnd[d], pMax[d]);
1353   }
1354   /* Loop over initial vertices and mark all faces in the collective star() */
1355   ierr = DMLabelGetStratumIS(vertexLabel, value, &subvertexIS);CHKERRQ(ierr);
1356   if (subvertexIS) {
1357     ierr = ISGetSize(subvertexIS, &numSubVerticesInitial);CHKERRQ(ierr);
1358     ierr = ISGetIndices(subvertexIS, &subvertices);CHKERRQ(ierr);
1359   }
1360   for (v = 0; v < numSubVerticesInitial; ++v) {
1361     const PetscInt vertex = subvertices[v];
1362     PetscInt      *star   = NULL;
1363     PetscInt       starSize, s, numFaces = 0, f;
1364 
1365     ierr = DMPlexGetTransitiveClosure(dm, vertex, PETSC_FALSE, &starSize, &star);CHKERRQ(ierr);
1366     for (s = 0; s < starSize*2; s += 2) {
1367       const PetscInt point = star[s];
1368       if ((point >= pStart[dim-1]) && (point < pEnd[dim-1])) star[numFaces++] = point;
1369     }
1370     for (f = 0; f < numFaces; ++f) {
1371       const PetscInt face    = star[f];
1372       PetscInt      *closure = NULL;
1373       PetscInt       closureSize, c;
1374       PetscInt       faceLoc;
1375 
1376       ierr = DMLabelGetValue(subpointMap, face, &faceLoc);CHKERRQ(ierr);
1377       if (faceLoc == dim-1) continue;
1378       if (faceLoc >= 0) SETERRQ2(PetscObjectComm((PetscObject)dm), PETSC_ERR_PLIB, "Face %d has dimension %d in the surface label", face, faceLoc);
1379       ierr = DMPlexGetTransitiveClosure(dm, face, PETSC_TRUE, &closureSize, &closure);CHKERRQ(ierr);
1380       for (c = 0; c < closureSize*2; c += 2) {
1381         const PetscInt point = closure[c];
1382         PetscInt       vertexLoc;
1383 
1384         if ((point >= pStart[0]) && (point < pEnd[0])) {
1385           ierr = DMLabelGetValue(vertexLabel, point, &vertexLoc);CHKERRQ(ierr);
1386           if (vertexLoc != value) break;
1387         }
1388       }
1389       if (c == closureSize*2) {
1390         const PetscInt *support;
1391         PetscInt        supportSize, s;
1392 
1393         for (c = 0; c < closureSize*2; c += 2) {
1394           const PetscInt point = closure[c];
1395 
1396           for (d = 0; d < dim; ++d) {
1397             if ((point >= pStart[d]) && (point < pEnd[d])) {
1398               ierr = DMLabelSetValue(subpointMap, point, d);CHKERRQ(ierr);
1399               break;
1400             }
1401           }
1402         }
1403         ierr = DMPlexGetSupportSize(dm, face, &supportSize);CHKERRQ(ierr);
1404         ierr = DMPlexGetSupport(dm, face, &support);CHKERRQ(ierr);
1405         for (s = 0; s < supportSize; ++s) {
1406           ierr = DMLabelSetValue(subpointMap, support[s], dim);CHKERRQ(ierr);
1407         }
1408       }
1409       ierr = DMPlexRestoreTransitiveClosure(dm, face, PETSC_TRUE, &closureSize, &closure);CHKERRQ(ierr);
1410     }
1411     ierr = DMPlexRestoreTransitiveClosure(dm, vertex, PETSC_FALSE, &starSize, &star);CHKERRQ(ierr);
1412   }
1413   if (subvertexIS) {
1414     ierr = ISRestoreIndices(subvertexIS, &subvertices);CHKERRQ(ierr);
1415   }
1416   ierr = ISDestroy(&subvertexIS);CHKERRQ(ierr);
1417   ierr = PetscFree3(pStart,pEnd,pMax);CHKERRQ(ierr);
1418   PetscFunctionReturn(0);
1419 }
1420 
1421 #undef __FUNCT__
1422 #define __FUNCT__ "DMPlexMarkCohesiveSubmesh_Uninterpolated"
1423 static PetscErrorCode DMPlexMarkCohesiveSubmesh_Uninterpolated(DM dm, PetscBool hasLagrange, const char labelname[], PetscInt value, DMLabel subpointMap, PetscInt *numFaces, PetscInt *nFV, PetscInt *subCells[], DM subdm)
1424 {
1425   DMLabel         label = NULL;
1426   const PetscInt *cone;
1427   PetscInt        dim, cMax, cEnd, c, subc = 0, p, coneSize;
1428   PetscErrorCode  ierr;
1429 
1430   PetscFunctionBegin;
1431   *numFaces = 0;
1432   *nFV = 0;
1433   if (labelname) {ierr = DMPlexGetLabel(dm, labelname, &label);CHKERRQ(ierr);}
1434   *subCells = NULL;
1435   ierr = DMPlexGetDimension(dm, &dim);CHKERRQ(ierr);
1436   ierr = DMPlexGetHeightStratum(dm, 0, NULL, &cEnd);CHKERRQ(ierr);
1437   ierr = DMPlexGetHybridBounds(dm, &cMax, NULL, NULL, NULL);CHKERRQ(ierr);
1438   if (cMax < 0) PetscFunctionReturn(0);
1439   if (label) {
1440     for (c = cMax; c < cEnd; ++c) {
1441       PetscInt val;
1442 
1443       ierr = DMLabelGetValue(label, c, &val);CHKERRQ(ierr);
1444       if (val == value) {
1445         ++(*numFaces);
1446         ierr = DMPlexGetConeSize(dm, c, &coneSize);CHKERRQ(ierr);
1447       }
1448     }
1449   } else {
1450     *numFaces = cEnd - cMax;
1451     ierr = DMPlexGetConeSize(dm, cMax, &coneSize);CHKERRQ(ierr);
1452   }
1453   *nFV = hasLagrange ? coneSize/3 : coneSize/2;
1454   ierr = PetscMalloc(*numFaces *2 * sizeof(PetscInt), subCells);CHKERRQ(ierr);
1455   for (c = cMax; c < cEnd; ++c) {
1456     const PetscInt *cells;
1457     PetscInt        numCells;
1458 
1459     if (label) {
1460       PetscInt val;
1461 
1462       ierr = DMLabelGetValue(label, c, &val);CHKERRQ(ierr);
1463       if (val != value) continue;
1464     }
1465     ierr = DMPlexGetCone(dm, c, &cone);CHKERRQ(ierr);
1466     for (p = 0; p < *nFV; ++p) {
1467       ierr = DMLabelSetValue(subpointMap, cone[p], 0);CHKERRQ(ierr);
1468     }
1469     /* Negative face */
1470     ierr = DMPlexGetJoin(dm, *nFV, cone, &numCells, &cells);CHKERRQ(ierr);
1471     /* Not true in parallel
1472     if (numCells != 2) SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Cohesive cells should separate two cells"); */
1473     for (p = 0; p < numCells; ++p) {
1474       ierr = DMLabelSetValue(subpointMap, cells[p], 2);CHKERRQ(ierr);
1475       (*subCells)[subc++] = cells[p];
1476     }
1477     ierr = DMPlexRestoreJoin(dm, *nFV, cone, &numCells, &cells);CHKERRQ(ierr);
1478     /* Positive face is not included */
1479   }
1480   PetscFunctionReturn(0);
1481 }
1482 
1483 #undef __FUNCT__
1484 #define __FUNCT__ "DMPlexMarkCohesiveSubmesh_Interpolated"
1485 static PetscErrorCode DMPlexMarkCohesiveSubmesh_Interpolated(DM dm, PetscBool hasLagrange, const char labelname[], PetscInt value, DMLabel subpointMap, DM subdm)
1486 {
1487   DMLabel        label = NULL;
1488   PetscInt      *pStart, *pEnd;
1489   PetscInt       dim, cMax, cEnd, c, d;
1490   PetscErrorCode ierr;
1491 
1492   PetscFunctionBegin;
1493   if (labelname) {ierr = DMPlexGetLabel(dm, labelname, &label);CHKERRQ(ierr);}
1494   ierr = DMPlexGetDimension(dm, &dim);CHKERRQ(ierr);
1495   ierr = DMPlexGetHeightStratum(dm, 0, NULL, &cEnd);CHKERRQ(ierr);
1496   ierr = DMPlexGetHybridBounds(dm, &cMax, NULL, NULL, NULL);CHKERRQ(ierr);
1497   if (cMax < 0) PetscFunctionReturn(0);
1498   ierr = PetscMalloc2(dim+1,PetscInt,&pStart,dim+1,PetscInt,&pEnd);CHKERRQ(ierr);
1499   for (d = 0; d <= dim; ++d) {
1500     ierr = DMPlexGetDepthStratum(dm, d, &pStart[d], &pEnd[d]);CHKERRQ(ierr);
1501   }
1502   for (c = cMax; c < cEnd; ++c) {
1503     const PetscInt *cone;
1504     PetscInt       *closure = NULL;
1505     PetscInt        coneSize, closureSize, cl;
1506 
1507     if (label) {
1508       PetscInt val;
1509 
1510       ierr = DMLabelGetValue(label, c, &val);CHKERRQ(ierr);
1511       if (val != value) continue;
1512     }
1513     ierr = DMPlexGetConeSize(dm, c, &coneSize);CHKERRQ(ierr);
1514     if (hasLagrange) {
1515       if (coneSize != 3) SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Cohesive cells should separate two cells");
1516     } else {
1517       if (coneSize != 2) SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Cohesive cells should separate two cells");
1518     }
1519     /* Negative face */
1520     ierr = DMPlexGetCone(dm, c, &cone);CHKERRQ(ierr);
1521     ierr = DMPlexGetTransitiveClosure(dm, cone[0], PETSC_TRUE, &closureSize, &closure);CHKERRQ(ierr);
1522     for (cl = 0; cl < closureSize*2; cl += 2) {
1523       const PetscInt point = closure[cl];
1524 
1525       for (d = 0; d <= dim; ++d) {
1526         if ((point >= pStart[d]) && (point < pEnd[d])) {
1527           ierr = DMLabelSetValue(subpointMap, point, d);CHKERRQ(ierr);
1528           break;
1529         }
1530       }
1531     }
1532     ierr = DMPlexRestoreTransitiveClosure(dm, cone[0], PETSC_TRUE, &closureSize, &closure);CHKERRQ(ierr);
1533     /* Cells -- positive face is not included */
1534     for (cl = 0; cl < 1; ++cl) {
1535       const PetscInt *support;
1536       PetscInt        supportSize, s;
1537 
1538       ierr = DMPlexGetSupportSize(dm, cone[cl], &supportSize);CHKERRQ(ierr);
1539       if (supportSize != 2) SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Cohesive faces should separate two cells");
1540       ierr = DMPlexGetSupport(dm, cone[cl], &support);CHKERRQ(ierr);
1541       for (s = 0; s < supportSize; ++s) {
1542         ierr = DMLabelSetValue(subpointMap, support[s], dim);CHKERRQ(ierr);
1543       }
1544     }
1545   }
1546   ierr = PetscFree2(pStart, pEnd);CHKERRQ(ierr);
1547   PetscFunctionReturn(0);
1548 }
1549 
1550 #undef __FUNCT__
1551 #define __FUNCT__ "DMPlexGetFaceOrientation"
1552 PetscErrorCode DMPlexGetFaceOrientation(DM dm, PetscInt cell, PetscInt numCorners, PetscInt indices[], PetscInt oppositeVertex, PetscInt origVertices[], PetscInt faceVertices[], PetscBool *posOriented)
1553 {
1554   MPI_Comm       comm;
1555   PetscBool      posOrient = PETSC_FALSE;
1556   const PetscInt debug     = 0;
1557   PetscInt       cellDim, faceSize, f;
1558   PetscErrorCode ierr;
1559 
1560   PetscFunctionBegin;
1561   ierr = PetscObjectGetComm((PetscObject)dm,&comm);CHKERRQ(ierr);
1562   ierr = DMPlexGetDimension(dm, &cellDim);CHKERRQ(ierr);
1563   if (debug) {PetscPrintf(comm, "cellDim: %d numCorners: %d\n", cellDim, numCorners);CHKERRQ(ierr);}
1564 
1565   if (cellDim == 1 && numCorners == 2) {
1566     /* Triangle */
1567     faceSize  = numCorners-1;
1568     posOrient = !(oppositeVertex%2) ? PETSC_TRUE : PETSC_FALSE;
1569   } else if (cellDim == 2 && numCorners == 3) {
1570     /* Triangle */
1571     faceSize  = numCorners-1;
1572     posOrient = !(oppositeVertex%2) ? PETSC_TRUE : PETSC_FALSE;
1573   } else if (cellDim == 3 && numCorners == 4) {
1574     /* Tetrahedron */
1575     faceSize  = numCorners-1;
1576     posOrient = (oppositeVertex%2) ? PETSC_TRUE : PETSC_FALSE;
1577   } else if (cellDim == 1 && numCorners == 3) {
1578     /* Quadratic line */
1579     faceSize  = 1;
1580     posOrient = PETSC_TRUE;
1581   } else if (cellDim == 2 && numCorners == 4) {
1582     /* Quads */
1583     faceSize = 2;
1584     if ((indices[1] > indices[0]) && (indices[1] - indices[0] == 1)) {
1585       posOrient = PETSC_TRUE;
1586     } else if ((indices[0] == 3) && (indices[1] == 0)) {
1587       posOrient = PETSC_TRUE;
1588     } else {
1589       if (((indices[0] > indices[1]) && (indices[0] - indices[1] == 1)) || ((indices[0] == 0) && (indices[1] == 3))) {
1590         posOrient = PETSC_FALSE;
1591       } else SETERRQ(comm, PETSC_ERR_ARG_WRONG, "Invalid quad crossedge");
1592     }
1593   } else if (cellDim == 2 && numCorners == 6) {
1594     /* Quadratic triangle (I hate this) */
1595     /* Edges are determined by the first 2 vertices (corners of edges) */
1596     const PetscInt faceSizeTri = 3;
1597     PetscInt       sortedIndices[3], i, iFace;
1598     PetscBool      found                    = PETSC_FALSE;
1599     PetscInt       faceVerticesTriSorted[9] = {
1600       0, 3,  4, /* bottom */
1601       1, 4,  5, /* right */
1602       2, 3,  5, /* left */
1603     };
1604     PetscInt       faceVerticesTri[9] = {
1605       0, 3,  4, /* bottom */
1606       1, 4,  5, /* right */
1607       2, 5,  3, /* left */
1608     };
1609 
1610     faceSize = faceSizeTri;
1611     for (i = 0; i < faceSizeTri; ++i) sortedIndices[i] = indices[i];
1612     ierr = PetscSortInt(faceSizeTri, sortedIndices);CHKERRQ(ierr);
1613     for (iFace = 0; iFace < 3; ++iFace) {
1614       const PetscInt ii = iFace*faceSizeTri;
1615       PetscInt       fVertex, cVertex;
1616 
1617       if ((sortedIndices[0] == faceVerticesTriSorted[ii+0]) &&
1618           (sortedIndices[1] == faceVerticesTriSorted[ii+1])) {
1619         for (fVertex = 0; fVertex < faceSizeTri; ++fVertex) {
1620           for (cVertex = 0; cVertex < faceSizeTri; ++cVertex) {
1621             if (indices[cVertex] == faceVerticesTri[ii+fVertex]) {
1622               faceVertices[fVertex] = origVertices[cVertex];
1623               break;
1624             }
1625           }
1626         }
1627         found = PETSC_TRUE;
1628         break;
1629       }
1630     }
1631     if (!found) SETERRQ(comm, PETSC_ERR_ARG_WRONG, "Invalid tri crossface");
1632     if (posOriented) *posOriented = PETSC_TRUE;
1633     PetscFunctionReturn(0);
1634   } else if (cellDim == 2 && numCorners == 9) {
1635     /* Quadratic quad (I hate this) */
1636     /* Edges are determined by the first 2 vertices (corners of edges) */
1637     const PetscInt faceSizeQuad = 3;
1638     PetscInt       sortedIndices[3], i, iFace;
1639     PetscBool      found                      = PETSC_FALSE;
1640     PetscInt       faceVerticesQuadSorted[12] = {
1641       0, 1,  4, /* bottom */
1642       1, 2,  5, /* right */
1643       2, 3,  6, /* top */
1644       0, 3,  7, /* left */
1645     };
1646     PetscInt       faceVerticesQuad[12] = {
1647       0, 1,  4, /* bottom */
1648       1, 2,  5, /* right */
1649       2, 3,  6, /* top */
1650       3, 0,  7, /* left */
1651     };
1652 
1653     faceSize = faceSizeQuad;
1654     for (i = 0; i < faceSizeQuad; ++i) sortedIndices[i] = indices[i];
1655     ierr = PetscSortInt(faceSizeQuad, sortedIndices);CHKERRQ(ierr);
1656     for (iFace = 0; iFace < 4; ++iFace) {
1657       const PetscInt ii = iFace*faceSizeQuad;
1658       PetscInt       fVertex, cVertex;
1659 
1660       if ((sortedIndices[0] == faceVerticesQuadSorted[ii+0]) &&
1661           (sortedIndices[1] == faceVerticesQuadSorted[ii+1])) {
1662         for (fVertex = 0; fVertex < faceSizeQuad; ++fVertex) {
1663           for (cVertex = 0; cVertex < faceSizeQuad; ++cVertex) {
1664             if (indices[cVertex] == faceVerticesQuad[ii+fVertex]) {
1665               faceVertices[fVertex] = origVertices[cVertex];
1666               break;
1667             }
1668           }
1669         }
1670         found = PETSC_TRUE;
1671         break;
1672       }
1673     }
1674     if (!found) SETERRQ(comm, PETSC_ERR_ARG_WRONG, "Invalid quad crossface");
1675     if (posOriented) *posOriented = PETSC_TRUE;
1676     PetscFunctionReturn(0);
1677   } else if (cellDim == 3 && numCorners == 8) {
1678     /* Hexes
1679        A hex is two oriented quads with the normal of the first
1680        pointing up at the second.
1681 
1682           7---6
1683          /|  /|
1684         4---5 |
1685         | 1-|-2
1686         |/  |/
1687         0---3
1688 
1689         Faces are determined by the first 4 vertices (corners of faces) */
1690     const PetscInt faceSizeHex = 4;
1691     PetscInt       sortedIndices[4], i, iFace;
1692     PetscBool      found                     = PETSC_FALSE;
1693     PetscInt       faceVerticesHexSorted[24] = {
1694       0, 1, 2, 3,  /* bottom */
1695       4, 5, 6, 7,  /* top */
1696       0, 3, 4, 5,  /* front */
1697       2, 3, 5, 6,  /* right */
1698       1, 2, 6, 7,  /* back */
1699       0, 1, 4, 7,  /* left */
1700     };
1701     PetscInt       faceVerticesHex[24] = {
1702       1, 2, 3, 0,  /* bottom */
1703       4, 5, 6, 7,  /* top */
1704       0, 3, 5, 4,  /* front */
1705       3, 2, 6, 5,  /* right */
1706       2, 1, 7, 6,  /* back */
1707       1, 0, 4, 7,  /* left */
1708     };
1709 
1710     faceSize = faceSizeHex;
1711     for (i = 0; i < faceSizeHex; ++i) sortedIndices[i] = indices[i];
1712     ierr = PetscSortInt(faceSizeHex, sortedIndices);CHKERRQ(ierr);
1713     for (iFace = 0; iFace < 6; ++iFace) {
1714       const PetscInt ii = iFace*faceSizeHex;
1715       PetscInt       fVertex, cVertex;
1716 
1717       if ((sortedIndices[0] == faceVerticesHexSorted[ii+0]) &&
1718           (sortedIndices[1] == faceVerticesHexSorted[ii+1]) &&
1719           (sortedIndices[2] == faceVerticesHexSorted[ii+2]) &&
1720           (sortedIndices[3] == faceVerticesHexSorted[ii+3])) {
1721         for (fVertex = 0; fVertex < faceSizeHex; ++fVertex) {
1722           for (cVertex = 0; cVertex < faceSizeHex; ++cVertex) {
1723             if (indices[cVertex] == faceVerticesHex[ii+fVertex]) {
1724               faceVertices[fVertex] = origVertices[cVertex];
1725               break;
1726             }
1727           }
1728         }
1729         found = PETSC_TRUE;
1730         break;
1731       }
1732     }
1733     if (!found) SETERRQ(comm, PETSC_ERR_ARG_WRONG, "Invalid hex crossface");
1734     if (posOriented) *posOriented = PETSC_TRUE;
1735     PetscFunctionReturn(0);
1736   } else if (cellDim == 3 && numCorners == 10) {
1737     /* Quadratic tet */
1738     /* Faces are determined by the first 3 vertices (corners of faces) */
1739     const PetscInt faceSizeTet = 6;
1740     PetscInt       sortedIndices[6], i, iFace;
1741     PetscBool      found                     = PETSC_FALSE;
1742     PetscInt       faceVerticesTetSorted[24] = {
1743       0, 1, 2,  6, 7, 8, /* bottom */
1744       0, 3, 4,  6, 7, 9,  /* front */
1745       1, 4, 5,  7, 8, 9,  /* right */
1746       2, 3, 5,  6, 8, 9,  /* left */
1747     };
1748     PetscInt       faceVerticesTet[24] = {
1749       0, 1, 2,  6, 7, 8, /* bottom */
1750       0, 4, 3,  6, 7, 9,  /* front */
1751       1, 5, 4,  7, 8, 9,  /* right */
1752       2, 3, 5,  8, 6, 9,  /* left */
1753     };
1754 
1755     faceSize = faceSizeTet;
1756     for (i = 0; i < faceSizeTet; ++i) sortedIndices[i] = indices[i];
1757     ierr = PetscSortInt(faceSizeTet, sortedIndices);CHKERRQ(ierr);
1758     for (iFace=0; iFace < 4; ++iFace) {
1759       const PetscInt ii = iFace*faceSizeTet;
1760       PetscInt       fVertex, cVertex;
1761 
1762       if ((sortedIndices[0] == faceVerticesTetSorted[ii+0]) &&
1763           (sortedIndices[1] == faceVerticesTetSorted[ii+1]) &&
1764           (sortedIndices[2] == faceVerticesTetSorted[ii+2]) &&
1765           (sortedIndices[3] == faceVerticesTetSorted[ii+3])) {
1766         for (fVertex = 0; fVertex < faceSizeTet; ++fVertex) {
1767           for (cVertex = 0; cVertex < faceSizeTet; ++cVertex) {
1768             if (indices[cVertex] == faceVerticesTet[ii+fVertex]) {
1769               faceVertices[fVertex] = origVertices[cVertex];
1770               break;
1771             }
1772           }
1773         }
1774         found = PETSC_TRUE;
1775         break;
1776       }
1777     }
1778     if (!found) SETERRQ(comm, PETSC_ERR_ARG_WRONG, "Invalid tet crossface");
1779     if (posOriented) *posOriented = PETSC_TRUE;
1780     PetscFunctionReturn(0);
1781   } else if (cellDim == 3 && numCorners == 27) {
1782     /* Quadratic hexes (I hate this)
1783        A hex is two oriented quads with the normal of the first
1784        pointing up at the second.
1785 
1786          7---6
1787         /|  /|
1788        4---5 |
1789        | 3-|-2
1790        |/  |/
1791        0---1
1792 
1793        Faces are determined by the first 4 vertices (corners of faces) */
1794     const PetscInt faceSizeQuadHex = 9;
1795     PetscInt       sortedIndices[9], i, iFace;
1796     PetscBool      found                         = PETSC_FALSE;
1797     PetscInt       faceVerticesQuadHexSorted[54] = {
1798       0, 1, 2, 3,  8, 9, 10, 11,  24, /* bottom */
1799       4, 5, 6, 7,  12, 13, 14, 15,  25, /* top */
1800       0, 1, 4, 5,  8, 12, 16, 17,  22, /* front */
1801       1, 2, 5, 6,  9, 13, 17, 18,  21, /* right */
1802       2, 3, 6, 7,  10, 14, 18, 19,  23, /* back */
1803       0, 3, 4, 7,  11, 15, 16, 19,  20, /* left */
1804     };
1805     PetscInt       faceVerticesQuadHex[54] = {
1806       3, 2, 1, 0,  10, 9, 8, 11,  24, /* bottom */
1807       4, 5, 6, 7,  12, 13, 14, 15,  25, /* top */
1808       0, 1, 5, 4,  8, 17, 12, 16,  22, /* front */
1809       1, 2, 6, 5,  9, 18, 13, 17,  21, /* right */
1810       2, 3, 7, 6,  10, 19, 14, 18,  23, /* back */
1811       3, 0, 4, 7,  11, 16, 15, 19,  20 /* left */
1812     };
1813 
1814     faceSize = faceSizeQuadHex;
1815     for (i = 0; i < faceSizeQuadHex; ++i) sortedIndices[i] = indices[i];
1816     ierr = PetscSortInt(faceSizeQuadHex, sortedIndices);CHKERRQ(ierr);
1817     for (iFace = 0; iFace < 6; ++iFace) {
1818       const PetscInt ii = iFace*faceSizeQuadHex;
1819       PetscInt       fVertex, cVertex;
1820 
1821       if ((sortedIndices[0] == faceVerticesQuadHexSorted[ii+0]) &&
1822           (sortedIndices[1] == faceVerticesQuadHexSorted[ii+1]) &&
1823           (sortedIndices[2] == faceVerticesQuadHexSorted[ii+2]) &&
1824           (sortedIndices[3] == faceVerticesQuadHexSorted[ii+3])) {
1825         for (fVertex = 0; fVertex < faceSizeQuadHex; ++fVertex) {
1826           for (cVertex = 0; cVertex < faceSizeQuadHex; ++cVertex) {
1827             if (indices[cVertex] == faceVerticesQuadHex[ii+fVertex]) {
1828               faceVertices[fVertex] = origVertices[cVertex];
1829               break;
1830             }
1831           }
1832         }
1833         found = PETSC_TRUE;
1834         break;
1835       }
1836     }
1837     if (!found) SETERRQ(comm, PETSC_ERR_ARG_WRONG, "Invalid hex crossface");
1838     if (posOriented) *posOriented = PETSC_TRUE;
1839     PetscFunctionReturn(0);
1840   } else SETERRQ(comm, PETSC_ERR_ARG_WRONG, "Unknown cell type for faceOrientation().");
1841   if (!posOrient) {
1842     if (debug) {ierr = PetscPrintf(comm, "  Reversing initial face orientation\n");CHKERRQ(ierr);}
1843     for (f = 0; f < faceSize; ++f) faceVertices[f] = origVertices[faceSize-1 - f];
1844   } else {
1845     if (debug) {ierr = PetscPrintf(comm, "  Keeping initial face orientation\n");CHKERRQ(ierr);}
1846     for (f = 0; f < faceSize; ++f) faceVertices[f] = origVertices[f];
1847   }
1848   if (posOriented) *posOriented = posOrient;
1849   PetscFunctionReturn(0);
1850 }
1851 
1852 #undef __FUNCT__
1853 #define __FUNCT__ "DMPlexGetOrientedFace"
1854 /*
1855     Given a cell and a face, as a set of vertices,
1856       return the oriented face, as a set of vertices, in faceVertices
1857     The orientation is such that the face normal points out of the cell
1858 */
1859 PetscErrorCode DMPlexGetOrientedFace(DM dm, PetscInt cell, PetscInt faceSize, const PetscInt face[], PetscInt numCorners, PetscInt indices[], PetscInt origVertices[], PetscInt faceVertices[], PetscBool *posOriented)
1860 {
1861   const PetscInt *cone = NULL;
1862   PetscInt        coneSize, v, f, v2;
1863   PetscInt        oppositeVertex = -1;
1864   PetscErrorCode  ierr;
1865 
1866   PetscFunctionBegin;
1867   ierr = DMPlexGetConeSize(dm, cell, &coneSize);CHKERRQ(ierr);
1868   ierr = DMPlexGetCone(dm, cell, &cone);CHKERRQ(ierr);
1869   for (v = 0, v2 = 0; v < coneSize; ++v) {
1870     PetscBool found = PETSC_FALSE;
1871 
1872     for (f = 0; f < faceSize; ++f) {
1873       if (face[f] == cone[v]) {
1874         found = PETSC_TRUE; break;
1875       }
1876     }
1877     if (found) {
1878       indices[v2]      = v;
1879       origVertices[v2] = cone[v];
1880       ++v2;
1881     } else {
1882       oppositeVertex = v;
1883     }
1884   }
1885   ierr = DMPlexGetFaceOrientation(dm, cell, numCorners, indices, oppositeVertex, origVertices, faceVertices, posOriented);CHKERRQ(ierr);
1886   PetscFunctionReturn(0);
1887 }
1888 
1889 #undef __FUNCT__
1890 #define __FUNCT__ "DMPlexInsertFace_Internal"
1891 /*
1892   DMPlexInsertFace_Internal - Puts a face into the mesh
1893 
1894   Not collective
1895 
1896   Input Parameters:
1897   + dm              - The DMPlex
1898   . numFaceVertex   - The number of vertices in the face
1899   . faceVertices    - The vertices in the face for dm
1900   . subfaceVertices - The vertices in the face for subdm
1901   . numCorners      - The number of vertices in the cell
1902   . cell            - A cell in dm containing the face
1903   . subcell         - A cell in subdm containing the face
1904   . firstFace       - First face in the mesh
1905   - newFacePoint    - Next face in the mesh
1906 
1907   Output Parameters:
1908   . newFacePoint - Contains next face point number on input, updated on output
1909 
1910   Level: developer
1911 */
1912 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)
1913 {
1914   MPI_Comm        comm;
1915   DM_Plex        *submesh = (DM_Plex*) subdm->data;
1916   const PetscInt *faces;
1917   PetscInt        numFaces, coneSize;
1918   PetscErrorCode  ierr;
1919 
1920   PetscFunctionBegin;
1921   ierr = PetscObjectGetComm((PetscObject)dm,&comm);CHKERRQ(ierr);
1922   ierr = DMPlexGetConeSize(subdm, subcell, &coneSize);CHKERRQ(ierr);
1923   if (coneSize != 1) SETERRQ2(comm, PETSC_ERR_ARG_OUTOFRANGE, "Cone size of cell %d is %d != 1", cell, coneSize);
1924 #if 0
1925   /* Cannot use this because support() has not been constructed yet */
1926   ierr = DMPlexGetJoin(subdm, numFaceVertices, subfaceVertices, &numFaces, &faces);CHKERRQ(ierr);
1927 #else
1928   {
1929     PetscInt f;
1930 
1931     numFaces = 0;
1932     ierr     = DMGetWorkArray(subdm, 1, PETSC_INT, (void **) &faces);CHKERRQ(ierr);
1933     for (f = firstFace; f < *newFacePoint; ++f) {
1934       PetscInt dof, off, d;
1935 
1936       ierr = PetscSectionGetDof(submesh->coneSection, f, &dof);CHKERRQ(ierr);
1937       ierr = PetscSectionGetOffset(submesh->coneSection, f, &off);CHKERRQ(ierr);
1938       /* Yes, I know this is quadratic, but I expect the sizes to be <5 */
1939       for (d = 0; d < dof; ++d) {
1940         const PetscInt p = submesh->cones[off+d];
1941         PetscInt       v;
1942 
1943         for (v = 0; v < numFaceVertices; ++v) {
1944           if (subfaceVertices[v] == p) break;
1945         }
1946         if (v == numFaceVertices) break;
1947       }
1948       if (d == dof) {
1949         numFaces               = 1;
1950         ((PetscInt*) faces)[0] = f;
1951       }
1952     }
1953   }
1954 #endif
1955   if (numFaces > 1) SETERRQ1(comm, PETSC_ERR_ARG_WRONG, "Vertex set had %d faces, not one", numFaces);
1956   else if (numFaces == 1) {
1957     /* Add the other cell neighbor for this face */
1958     ierr = DMPlexSetCone(subdm, subcell, faces);CHKERRQ(ierr);
1959   } else {
1960     PetscInt *indices, *origVertices, *orientedVertices, *orientedSubVertices, v, ov;
1961     PetscBool posOriented;
1962 
1963     ierr                = DMGetWorkArray(subdm, 4*numFaceVertices * sizeof(PetscInt), PETSC_INT, &orientedVertices);CHKERRQ(ierr);
1964     origVertices        = &orientedVertices[numFaceVertices];
1965     indices             = &orientedVertices[numFaceVertices*2];
1966     orientedSubVertices = &orientedVertices[numFaceVertices*3];
1967     ierr                = DMPlexGetOrientedFace(dm, cell, numFaceVertices, faceVertices, numCorners, indices, origVertices, orientedVertices, &posOriented);CHKERRQ(ierr);
1968     /* TODO: I know that routine should return a permutation, not the indices */
1969     for (v = 0; v < numFaceVertices; ++v) {
1970       const PetscInt vertex = faceVertices[v], subvertex = subfaceVertices[v];
1971       for (ov = 0; ov < numFaceVertices; ++ov) {
1972         if (orientedVertices[ov] == vertex) {
1973           orientedSubVertices[ov] = subvertex;
1974           break;
1975         }
1976       }
1977       if (ov == numFaceVertices) SETERRQ1(comm, PETSC_ERR_PLIB, "Could not find face vertex %d in orientated set", vertex);
1978     }
1979     ierr = DMPlexSetCone(subdm, *newFacePoint, orientedSubVertices);CHKERRQ(ierr);
1980     ierr = DMPlexSetCone(subdm, subcell, newFacePoint);CHKERRQ(ierr);
1981     ierr = DMRestoreWorkArray(subdm, 4*numFaceVertices * sizeof(PetscInt), PETSC_INT, &orientedVertices);CHKERRQ(ierr);
1982     ++(*newFacePoint);
1983   }
1984 #if 0
1985   ierr = DMPlexRestoreJoin(subdm, numFaceVertices, subfaceVertices, &numFaces, &faces);CHKERRQ(ierr);
1986 #else
1987   ierr = DMRestoreWorkArray(subdm, 1, PETSC_INT, (void **) &faces);CHKERRQ(ierr);
1988 #endif
1989   PetscFunctionReturn(0);
1990 }
1991 
1992 #undef __FUNCT__
1993 #define __FUNCT__ "DMPlexCreateSubmesh_Uninterpolated"
1994 static PetscErrorCode DMPlexCreateSubmesh_Uninterpolated(DM dm, DMLabel vertexLabel, PetscInt value, DM subdm)
1995 {
1996   MPI_Comm        comm;
1997   DMLabel         subpointMap;
1998   IS              subvertexIS,  subcellIS;
1999   const PetscInt *subVertices, *subCells;
2000   PetscInt        numSubVertices, firstSubVertex, numSubCells;
2001   PetscInt       *subface, maxConeSize, numSubFaces = 0, firstSubFace, newFacePoint, nFV = 0;
2002   PetscInt        vStart, vEnd, c, f;
2003   PetscErrorCode  ierr;
2004 
2005   PetscFunctionBegin;
2006   ierr = PetscObjectGetComm((PetscObject)dm,&comm);CHKERRQ(ierr);
2007   /* Create subpointMap which marks the submesh */
2008   ierr = DMLabelCreate("subpoint_map", &subpointMap);CHKERRQ(ierr);
2009   ierr = DMPlexSetSubpointMap(subdm, subpointMap);CHKERRQ(ierr);
2010   ierr = DMLabelDestroy(&subpointMap);CHKERRQ(ierr);
2011   if (vertexLabel) {ierr = DMPlexMarkSubmesh_Uninterpolated(dm, vertexLabel, value, subpointMap, &numSubFaces, &nFV, subdm);CHKERRQ(ierr);}
2012   /* Setup chart */
2013   ierr = DMLabelGetStratumSize(subpointMap, 0, &numSubVertices);CHKERRQ(ierr);
2014   ierr = DMLabelGetStratumSize(subpointMap, 2, &numSubCells);CHKERRQ(ierr);
2015   ierr = DMPlexSetChart(subdm, 0, numSubCells+numSubFaces+numSubVertices);CHKERRQ(ierr);
2016   ierr = DMPlexSetVTKCellHeight(subdm, 1);CHKERRQ(ierr);
2017   /* Set cone sizes */
2018   firstSubVertex = numSubCells;
2019   firstSubFace   = numSubCells+numSubVertices;
2020   newFacePoint   = firstSubFace;
2021   ierr = DMLabelGetStratumIS(subpointMap, 0, &subvertexIS);CHKERRQ(ierr);
2022   if (subvertexIS) {ierr = ISGetIndices(subvertexIS, &subVertices);CHKERRQ(ierr);}
2023   ierr = DMLabelGetStratumIS(subpointMap, 2, &subcellIS);CHKERRQ(ierr);
2024   if (subcellIS) {ierr = ISGetIndices(subcellIS, &subCells);CHKERRQ(ierr);}
2025   for (c = 0; c < numSubCells; ++c) {
2026     ierr = DMPlexSetConeSize(subdm, c, 1);CHKERRQ(ierr);
2027   }
2028   for (f = firstSubFace; f < firstSubFace+numSubFaces; ++f) {
2029     ierr = DMPlexSetConeSize(subdm, f, nFV);CHKERRQ(ierr);
2030   }
2031   ierr = DMSetUp(subdm);CHKERRQ(ierr);
2032   /* Create face cones */
2033   ierr = DMPlexGetDepthStratum(dm, 0, &vStart, &vEnd);CHKERRQ(ierr);
2034   ierr = DMPlexGetMaxSizes(dm, &maxConeSize, NULL);CHKERRQ(ierr);
2035   ierr = DMGetWorkArray(subdm, maxConeSize, PETSC_INT, (void**) &subface);CHKERRQ(ierr);
2036   for (c = 0; c < numSubCells; ++c) {
2037     const PetscInt cell    = subCells[c];
2038     const PetscInt subcell = c;
2039     PetscInt      *closure = NULL;
2040     PetscInt       closureSize, cl, numCorners = 0, faceSize = 0;
2041 
2042     ierr = DMPlexGetTransitiveClosure(dm, cell, PETSC_TRUE, &closureSize, &closure);CHKERRQ(ierr);
2043     for (cl = 0; cl < closureSize*2; cl += 2) {
2044       const PetscInt point = closure[cl];
2045       PetscInt       subVertex;
2046 
2047       if ((point >= vStart) && (point < vEnd)) {
2048         ++numCorners;
2049         ierr = PetscFindInt(point, numSubVertices, subVertices, &subVertex);CHKERRQ(ierr);
2050         if (subVertex >= 0) {
2051           closure[faceSize] = point;
2052           subface[faceSize] = firstSubVertex+subVertex;
2053           ++faceSize;
2054         }
2055       }
2056     }
2057     if (faceSize > nFV) SETERRQ1(comm, PETSC_ERR_ARG_WRONG, "Invalid submesh: Too many vertices %d of an element on the surface", faceSize);
2058     if (faceSize == nFV) {
2059       ierr = DMPlexInsertFace_Internal(dm, subdm, faceSize, closure, subface, numCorners, cell, subcell, firstSubFace, &newFacePoint);CHKERRQ(ierr);
2060     }
2061     ierr = DMPlexRestoreTransitiveClosure(dm, cell, PETSC_TRUE, &closureSize, &closure);CHKERRQ(ierr);
2062   }
2063   ierr = DMRestoreWorkArray(subdm, maxConeSize, PETSC_INT, (void**) &subface);CHKERRQ(ierr);
2064   ierr = DMPlexSymmetrize(subdm);CHKERRQ(ierr);
2065   ierr = DMPlexStratify(subdm);CHKERRQ(ierr);
2066   /* Build coordinates */
2067   {
2068     PetscSection coordSection, subCoordSection;
2069     Vec          coordinates, subCoordinates;
2070     PetscScalar *coords, *subCoords;
2071     PetscInt     numComp, coordSize, v;
2072 
2073     ierr = DMPlexGetCoordinateSection(dm, &coordSection);CHKERRQ(ierr);
2074     ierr = DMGetCoordinatesLocal(dm, &coordinates);CHKERRQ(ierr);
2075     ierr = DMPlexGetCoordinateSection(subdm, &subCoordSection);CHKERRQ(ierr);
2076     ierr = PetscSectionSetNumFields(subCoordSection, 1);CHKERRQ(ierr);
2077     ierr = PetscSectionGetFieldComponents(coordSection, 0, &numComp);CHKERRQ(ierr);
2078     ierr = PetscSectionSetFieldComponents(subCoordSection, 0, numComp);CHKERRQ(ierr);
2079     ierr = PetscSectionSetChart(subCoordSection, firstSubVertex, firstSubVertex+numSubVertices);CHKERRQ(ierr);
2080     for (v = 0; v < numSubVertices; ++v) {
2081       const PetscInt vertex    = subVertices[v];
2082       const PetscInt subvertex = firstSubVertex+v;
2083       PetscInt       dof;
2084 
2085       ierr = PetscSectionGetDof(coordSection, vertex, &dof);CHKERRQ(ierr);
2086       ierr = PetscSectionSetDof(subCoordSection, subvertex, dof);CHKERRQ(ierr);
2087       ierr = PetscSectionSetFieldDof(subCoordSection, subvertex, 0, dof);CHKERRQ(ierr);
2088     }
2089     ierr = PetscSectionSetUp(subCoordSection);CHKERRQ(ierr);
2090     ierr = PetscSectionGetStorageSize(subCoordSection, &coordSize);CHKERRQ(ierr);
2091     ierr = VecCreate(comm, &subCoordinates);CHKERRQ(ierr);
2092     ierr = VecSetSizes(subCoordinates, coordSize, PETSC_DETERMINE);CHKERRQ(ierr);
2093     ierr = VecSetType(subCoordinates,dm->vectype);CHKERRQ(ierr);
2094     if (coordSize) {
2095       ierr = VecGetArray(coordinates,    &coords);CHKERRQ(ierr);
2096       ierr = VecGetArray(subCoordinates, &subCoords);CHKERRQ(ierr);
2097       for (v = 0; v < numSubVertices; ++v) {
2098         const PetscInt vertex    = subVertices[v];
2099         const PetscInt subvertex = firstSubVertex+v;
2100         PetscInt       dof, off, sdof, soff, d;
2101 
2102         ierr = PetscSectionGetDof(coordSection, vertex, &dof);CHKERRQ(ierr);
2103         ierr = PetscSectionGetOffset(coordSection, vertex, &off);CHKERRQ(ierr);
2104         ierr = PetscSectionGetDof(subCoordSection, subvertex, &sdof);CHKERRQ(ierr);
2105         ierr = PetscSectionGetOffset(subCoordSection, subvertex, &soff);CHKERRQ(ierr);
2106         if (dof != sdof) SETERRQ4(comm, PETSC_ERR_PLIB, "Coordinate dimension %d on subvertex %d, vertex %d should be %d", sdof, subvertex, vertex, dof);
2107         for (d = 0; d < dof; ++d) subCoords[soff+d] = coords[off+d];
2108       }
2109       ierr = VecRestoreArray(coordinates,    &coords);CHKERRQ(ierr);
2110       ierr = VecRestoreArray(subCoordinates, &subCoords);CHKERRQ(ierr);
2111     }
2112     ierr = DMSetCoordinatesLocal(subdm, subCoordinates);CHKERRQ(ierr);
2113     ierr = VecDestroy(&subCoordinates);CHKERRQ(ierr);
2114   }
2115   /* Cleanup */
2116   if (subvertexIS) {ierr = ISRestoreIndices(subvertexIS, &subVertices);CHKERRQ(ierr);}
2117   ierr = ISDestroy(&subvertexIS);CHKERRQ(ierr);
2118   if (subcellIS) {ierr = ISRestoreIndices(subcellIS, &subCells);CHKERRQ(ierr);}
2119   ierr = ISDestroy(&subcellIS);CHKERRQ(ierr);
2120   PetscFunctionReturn(0);
2121 }
2122 
2123 #undef __FUNCT__
2124 #define __FUNCT__ "DMPlexCreateSubmesh_Interpolated"
2125 static PetscErrorCode DMPlexCreateSubmesh_Interpolated(DM dm, DMLabel vertexLabel, PetscInt value, DM subdm)
2126 {
2127   MPI_Comm         comm;
2128   DMLabel          subpointMap;
2129   IS              *subpointIS;
2130   const PetscInt **subpoints;
2131   PetscInt        *numSubPoints, *firstSubPoint, *coneNew, *coneONew;
2132   PetscInt         totSubPoints = 0, maxConeSize, dim, p, d, v;
2133   PetscErrorCode   ierr;
2134 
2135   PetscFunctionBegin;
2136   ierr = PetscObjectGetComm((PetscObject)dm,&comm);CHKERRQ(ierr);
2137   /* Create subpointMap which marks the submesh */
2138   ierr = DMLabelCreate("subpoint_map", &subpointMap);CHKERRQ(ierr);
2139   ierr = DMPlexSetSubpointMap(subdm, subpointMap);CHKERRQ(ierr);
2140   ierr = DMLabelDestroy(&subpointMap);CHKERRQ(ierr);
2141   if (vertexLabel) {ierr = DMPlexMarkSubmesh_Interpolated(dm, vertexLabel, value, subpointMap, subdm);CHKERRQ(ierr);}
2142   /* Setup chart */
2143   ierr = DMPlexGetDimension(dm, &dim);CHKERRQ(ierr);
2144   ierr = PetscMalloc4(dim+1,PetscInt,&numSubPoints,dim+1,PetscInt,&firstSubPoint,dim+1,IS,&subpointIS,dim+1,const PetscInt *,&subpoints);CHKERRQ(ierr);
2145   for (d = 0; d <= dim; ++d) {
2146     ierr = DMLabelGetStratumSize(subpointMap, d, &numSubPoints[d]);CHKERRQ(ierr);
2147     totSubPoints += numSubPoints[d];
2148   }
2149   ierr = DMPlexSetChart(subdm, 0, totSubPoints);CHKERRQ(ierr);
2150   ierr = DMPlexSetVTKCellHeight(subdm, 1);CHKERRQ(ierr);
2151   /* Set cone sizes */
2152   firstSubPoint[dim] = 0;
2153   firstSubPoint[0]   = firstSubPoint[dim] + numSubPoints[dim];
2154   if (dim > 1) {firstSubPoint[dim-1] = firstSubPoint[0]     + numSubPoints[0];}
2155   if (dim > 2) {firstSubPoint[dim-2] = firstSubPoint[dim-1] + numSubPoints[dim-1];}
2156   for (d = 0; d <= dim; ++d) {
2157     ierr = DMLabelGetStratumIS(subpointMap, d, &subpointIS[d]);CHKERRQ(ierr);
2158     ierr = ISGetIndices(subpointIS[d], &subpoints[d]);CHKERRQ(ierr);
2159   }
2160   for (d = 0; d <= dim; ++d) {
2161     for (p = 0; p < numSubPoints[d]; ++p) {
2162       const PetscInt  point    = subpoints[d][p];
2163       const PetscInt  subpoint = firstSubPoint[d] + p;
2164       const PetscInt *cone;
2165       PetscInt        coneSize, coneSizeNew, c, val;
2166 
2167       ierr = DMPlexGetConeSize(dm, point, &coneSize);CHKERRQ(ierr);
2168       ierr = DMPlexSetConeSize(subdm, subpoint, coneSize);CHKERRQ(ierr);
2169       if (d == dim) {
2170         ierr = DMPlexGetCone(dm, point, &cone);CHKERRQ(ierr);
2171         for (c = 0, coneSizeNew = 0; c < coneSize; ++c) {
2172           ierr = DMLabelGetValue(subpointMap, cone[c], &val);CHKERRQ(ierr);
2173           if (val >= 0) coneSizeNew++;
2174         }
2175         ierr = DMPlexSetConeSize(subdm, subpoint, coneSizeNew);CHKERRQ(ierr);
2176       }
2177     }
2178   }
2179   ierr = DMSetUp(subdm);CHKERRQ(ierr);
2180   /* Set cones */
2181   ierr = DMPlexGetMaxSizes(dm, &maxConeSize, NULL);CHKERRQ(ierr);
2182   ierr = PetscMalloc2(maxConeSize,PetscInt,&coneNew,maxConeSize,PetscInt,&coneONew);CHKERRQ(ierr);
2183   for (d = 0; d <= dim; ++d) {
2184     for (p = 0; p < numSubPoints[d]; ++p) {
2185       const PetscInt  point    = subpoints[d][p];
2186       const PetscInt  subpoint = firstSubPoint[d] + p;
2187       const PetscInt *cone, *ornt;
2188       PetscInt        coneSize, subconeSize, coneSizeNew, c, subc;
2189 
2190       ierr = DMPlexGetConeSize(dm, point, &coneSize);CHKERRQ(ierr);
2191       ierr = DMPlexGetConeSize(subdm, subpoint, &subconeSize);CHKERRQ(ierr);
2192       ierr = DMPlexGetCone(dm, point, &cone);CHKERRQ(ierr);
2193       ierr = DMPlexGetConeOrientation(dm, point, &ornt);CHKERRQ(ierr);
2194       for (c = 0, coneSizeNew = 0; c < coneSize; ++c) {
2195         ierr = PetscFindInt(cone[c], numSubPoints[d-1], subpoints[d-1], &subc);CHKERRQ(ierr);
2196         if (subc >= 0) {
2197           coneNew[coneSizeNew]  = firstSubPoint[d-1] + subc;
2198           coneONew[coneSizeNew] = ornt[c];
2199           ++coneSizeNew;
2200         }
2201       }
2202       if (coneSizeNew != subconeSize) SETERRQ2(comm, PETSC_ERR_PLIB, "Number of cone points located %d does not match subcone size %d", coneSizeNew, subconeSize);
2203       ierr = DMPlexSetCone(subdm, subpoint, coneNew);CHKERRQ(ierr);
2204       ierr = DMPlexSetConeOrientation(subdm, subpoint, coneONew);CHKERRQ(ierr);
2205     }
2206   }
2207   ierr = PetscFree2(coneNew,coneONew);CHKERRQ(ierr);
2208   ierr = DMPlexSymmetrize(subdm);CHKERRQ(ierr);
2209   ierr = DMPlexStratify(subdm);CHKERRQ(ierr);
2210   /* Build coordinates */
2211   {
2212     PetscSection coordSection, subCoordSection;
2213     Vec          coordinates, subCoordinates;
2214     PetscScalar *coords, *subCoords;
2215     PetscInt     numComp, coordSize;
2216 
2217     ierr = DMPlexGetCoordinateSection(dm, &coordSection);CHKERRQ(ierr);
2218     ierr = DMGetCoordinatesLocal(dm, &coordinates);CHKERRQ(ierr);
2219     ierr = DMPlexGetCoordinateSection(subdm, &subCoordSection);CHKERRQ(ierr);
2220     ierr = PetscSectionSetNumFields(subCoordSection, 1);CHKERRQ(ierr);
2221     ierr = PetscSectionGetFieldComponents(coordSection, 0, &numComp);CHKERRQ(ierr);
2222     ierr = PetscSectionSetFieldComponents(subCoordSection, 0, numComp);CHKERRQ(ierr);
2223     ierr = PetscSectionSetChart(subCoordSection, firstSubPoint[0], firstSubPoint[0]+numSubPoints[0]);CHKERRQ(ierr);
2224     for (v = 0; v < numSubPoints[0]; ++v) {
2225       const PetscInt vertex    = subpoints[0][v];
2226       const PetscInt subvertex = firstSubPoint[0]+v;
2227       PetscInt       dof;
2228 
2229       ierr = PetscSectionGetDof(coordSection, vertex, &dof);CHKERRQ(ierr);
2230       ierr = PetscSectionSetDof(subCoordSection, subvertex, dof);CHKERRQ(ierr);
2231       ierr = PetscSectionSetFieldDof(subCoordSection, subvertex, 0, dof);CHKERRQ(ierr);
2232     }
2233     ierr = PetscSectionSetUp(subCoordSection);CHKERRQ(ierr);
2234     ierr = PetscSectionGetStorageSize(subCoordSection, &coordSize);CHKERRQ(ierr);
2235     ierr = VecCreate(comm, &subCoordinates);CHKERRQ(ierr);
2236     ierr = VecSetSizes(subCoordinates, coordSize, PETSC_DETERMINE);CHKERRQ(ierr);
2237     ierr = VecSetType(subCoordinates,dm->vectype);CHKERRQ(ierr);
2238     ierr = VecGetArray(coordinates,    &coords);CHKERRQ(ierr);
2239     ierr = VecGetArray(subCoordinates, &subCoords);CHKERRQ(ierr);
2240     for (v = 0; v < numSubPoints[0]; ++v) {
2241       const PetscInt vertex    = subpoints[0][v];
2242       const PetscInt subvertex = firstSubPoint[0]+v;
2243       PetscInt dof, off, sdof, soff, d;
2244 
2245       ierr = PetscSectionGetDof(coordSection, vertex, &dof);CHKERRQ(ierr);
2246       ierr = PetscSectionGetOffset(coordSection, vertex, &off);CHKERRQ(ierr);
2247       ierr = PetscSectionGetDof(subCoordSection, subvertex, &sdof);CHKERRQ(ierr);
2248       ierr = PetscSectionGetOffset(subCoordSection, subvertex, &soff);CHKERRQ(ierr);
2249       if (dof != sdof) SETERRQ4(comm, PETSC_ERR_PLIB, "Coordinate dimension %d on subvertex %d, vertex %d should be %d", sdof, subvertex, vertex, dof);
2250       for (d = 0; d < dof; ++d) subCoords[soff+d] = coords[off+d];
2251     }
2252     ierr = VecRestoreArray(coordinates,    &coords);CHKERRQ(ierr);
2253     ierr = VecRestoreArray(subCoordinates, &subCoords);CHKERRQ(ierr);
2254     ierr = DMSetCoordinatesLocal(subdm, subCoordinates);CHKERRQ(ierr);
2255     ierr = VecDestroy(&subCoordinates);CHKERRQ(ierr);
2256   }
2257   /* Cleanup */
2258   for (d = 0; d <= dim; ++d) {
2259     ierr = ISRestoreIndices(subpointIS[d], &subpoints[d]);CHKERRQ(ierr);
2260     ierr = ISDestroy(&subpointIS[d]);CHKERRQ(ierr);
2261   }
2262   ierr = PetscFree4(numSubPoints,firstSubPoint,subpointIS,subpoints);CHKERRQ(ierr);
2263   PetscFunctionReturn(0);
2264 }
2265 
2266 #undef __FUNCT__
2267 #define __FUNCT__ "DMPlexCreateSubmesh"
2268 /*@C
2269   DMPlexCreateSubmesh - Extract a hypersurface from the mesh using vertices defined by a label
2270 
2271   Input Parameters:
2272 + dm           - The original mesh
2273 . vertexLabel  - The DMLabel marking vertices contained in the surface
2274 - value        - The label value to use
2275 
2276   Output Parameter:
2277 . subdm - The surface mesh
2278 
2279   Note: This function produces a DMLabel mapping original points in the submesh to their depth. This can be obtained using DMPlexGetSubpointMap().
2280 
2281   Level: developer
2282 
2283 .seealso: DMPlexGetSubpointMap(), DMPlexGetLabel(), DMLabelSetValue()
2284 @*/
2285 PetscErrorCode DMPlexCreateSubmesh(DM dm, DMLabel vertexLabel, PetscInt value, DM *subdm)
2286 {
2287   PetscInt       dim, depth;
2288   PetscErrorCode ierr;
2289 
2290   PetscFunctionBegin;
2291   PetscValidHeaderSpecific(dm, DM_CLASSID, 1);
2292   PetscValidPointer(subdm, 3);
2293   ierr = DMPlexGetDimension(dm, &dim);CHKERRQ(ierr);
2294   ierr = DMPlexGetDepth(dm, &depth);CHKERRQ(ierr);
2295   ierr = DMCreate(PetscObjectComm((PetscObject)dm), subdm);CHKERRQ(ierr);
2296   ierr = DMSetType(*subdm, DMPLEX);CHKERRQ(ierr);
2297   ierr = DMPlexSetDimension(*subdm, dim-1);CHKERRQ(ierr);
2298   if (depth == dim) {
2299     ierr = DMPlexCreateSubmesh_Interpolated(dm, vertexLabel, value, *subdm);CHKERRQ(ierr);
2300   } else {
2301     ierr = DMPlexCreateSubmesh_Uninterpolated(dm, vertexLabel, value, *subdm);CHKERRQ(ierr);
2302   }
2303   PetscFunctionReturn(0);
2304 }
2305 
2306 #undef __FUNCT__
2307 #define __FUNCT__ "DMPlexFilterPoint_Internal"
2308 PETSC_STATIC_INLINE PetscInt DMPlexFilterPoint_Internal(PetscInt point, PetscInt firstSubPoint, PetscInt numSubPoints, const PetscInt subPoints[])
2309 {
2310   PetscInt       subPoint;
2311   PetscErrorCode ierr;
2312 
2313   ierr = PetscFindInt(point, numSubPoints, subPoints, &subPoint); if (ierr < 0) return ierr;
2314   return subPoint < 0 ? subPoint : firstSubPoint+subPoint;
2315 }
2316 
2317 #undef __FUNCT__
2318 #define __FUNCT__ "DMPlexCreateCohesiveSubmesh_Uninterpolated"
2319 static PetscErrorCode DMPlexCreateCohesiveSubmesh_Uninterpolated(DM dm, PetscBool hasLagrange, const char label[], PetscInt value, DM subdm)
2320 {
2321   MPI_Comm        comm;
2322   DMLabel         subpointMap;
2323   IS              subvertexIS;
2324   const PetscInt *subVertices;
2325   PetscInt        numSubVertices, firstSubVertex, numSubCells, *subCells = NULL;
2326   PetscInt       *subface, maxConeSize, numSubFaces, firstSubFace, newFacePoint, nFV;
2327   PetscInt        cMax, c, f;
2328   PetscErrorCode  ierr;
2329 
2330   PetscFunctionBegin;
2331   ierr = PetscObjectGetComm((PetscObject)dm, &comm);CHKERRQ(ierr);
2332   /* Create subpointMap which marks the submesh */
2333   ierr = DMLabelCreate("subpoint_map", &subpointMap);CHKERRQ(ierr);
2334   ierr = DMPlexSetSubpointMap(subdm, subpointMap);CHKERRQ(ierr);
2335   ierr = DMLabelDestroy(&subpointMap);CHKERRQ(ierr);
2336   ierr = DMPlexMarkCohesiveSubmesh_Uninterpolated(dm, hasLagrange, label, value, subpointMap, &numSubFaces, &nFV, &subCells, subdm);CHKERRQ(ierr);
2337   /* Setup chart */
2338   ierr = DMLabelGetStratumSize(subpointMap, 0, &numSubVertices);CHKERRQ(ierr);
2339   ierr = DMLabelGetStratumSize(subpointMap, 2, &numSubCells);CHKERRQ(ierr);
2340   ierr = DMPlexSetChart(subdm, 0, numSubCells+numSubFaces+numSubVertices);CHKERRQ(ierr);
2341   ierr = DMPlexSetVTKCellHeight(subdm, 1);CHKERRQ(ierr);
2342   /* Set cone sizes */
2343   firstSubVertex = numSubCells;
2344   firstSubFace   = numSubCells+numSubVertices;
2345   newFacePoint   = firstSubFace;
2346   ierr = DMLabelGetStratumIS(subpointMap, 0, &subvertexIS);CHKERRQ(ierr);
2347   if (subvertexIS) {ierr = ISGetIndices(subvertexIS, &subVertices);CHKERRQ(ierr);}
2348   for (c = 0; c < numSubCells; ++c) {
2349     ierr = DMPlexSetConeSize(subdm, c, 1);CHKERRQ(ierr);
2350   }
2351   for (f = firstSubFace; f < firstSubFace+numSubFaces; ++f) {
2352     ierr = DMPlexSetConeSize(subdm, f, nFV);CHKERRQ(ierr);
2353   }
2354   ierr = DMSetUp(subdm);CHKERRQ(ierr);
2355   /* Create face cones */
2356   ierr = DMPlexGetMaxSizes(dm, &maxConeSize, NULL);CHKERRQ(ierr);
2357   ierr = DMPlexGetHybridBounds(dm, &cMax, NULL, NULL, NULL);CHKERRQ(ierr);
2358   ierr = DMGetWorkArray(subdm, maxConeSize, PETSC_INT, (void**) &subface);CHKERRQ(ierr);
2359   for (c = 0; c < numSubCells; ++c) {
2360     const PetscInt  cell    = subCells[c];
2361     const PetscInt  subcell = c;
2362     const PetscInt *cone, *cells;
2363     PetscInt        numCells, subVertex, p, v;
2364 
2365     if (cell < cMax) continue;
2366     ierr = DMPlexGetCone(dm, cell, &cone);CHKERRQ(ierr);
2367     for (v = 0; v < nFV; ++v) {
2368       ierr = PetscFindInt(cone[v], numSubVertices, subVertices, &subVertex);CHKERRQ(ierr);
2369       subface[v] = firstSubVertex+subVertex;
2370     }
2371     ierr = DMPlexSetCone(subdm, newFacePoint, subface);CHKERRQ(ierr);
2372     ierr = DMPlexSetCone(subdm, subcell, &newFacePoint);CHKERRQ(ierr);
2373     ierr = DMPlexGetJoin(dm, nFV, cone, &numCells, &cells);CHKERRQ(ierr);
2374     /* Not true in parallel
2375     if (numCells != 2) SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Cohesive cells should separate two cells"); */
2376     for (p = 0; p < numCells; ++p) {
2377       PetscInt negsubcell;
2378 
2379       if (cells[p] >= cMax) continue;
2380       /* I know this is a crap search */
2381       for (negsubcell = 0; negsubcell < numSubCells; ++negsubcell) {
2382         if (subCells[negsubcell] == cells[p]) break;
2383       }
2384       if (negsubcell == numSubCells) SETERRQ1(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Could not find negative face neighbor for cohesive cell %d", cell);
2385       ierr = DMPlexSetCone(subdm, negsubcell, &newFacePoint);CHKERRQ(ierr);
2386     }
2387     ierr = DMPlexRestoreJoin(dm, nFV, cone, &numCells, &cells);CHKERRQ(ierr);
2388     ++newFacePoint;
2389   }
2390   ierr = DMRestoreWorkArray(subdm, maxConeSize, PETSC_INT, (void**) &subface);CHKERRQ(ierr);
2391   ierr = DMPlexSymmetrize(subdm);CHKERRQ(ierr);
2392   ierr = DMPlexStratify(subdm);CHKERRQ(ierr);
2393   /* Build coordinates */
2394   {
2395     PetscSection coordSection, subCoordSection;
2396     Vec          coordinates, subCoordinates;
2397     PetscScalar *coords, *subCoords;
2398     PetscInt     numComp, coordSize, v;
2399 
2400     ierr = DMPlexGetCoordinateSection(dm, &coordSection);CHKERRQ(ierr);
2401     ierr = DMGetCoordinatesLocal(dm, &coordinates);CHKERRQ(ierr);
2402     ierr = DMPlexGetCoordinateSection(subdm, &subCoordSection);CHKERRQ(ierr);
2403     ierr = PetscSectionSetNumFields(subCoordSection, 1);CHKERRQ(ierr);
2404     ierr = PetscSectionGetFieldComponents(coordSection, 0, &numComp);CHKERRQ(ierr);
2405     ierr = PetscSectionSetFieldComponents(subCoordSection, 0, numComp);CHKERRQ(ierr);
2406     ierr = PetscSectionSetChart(subCoordSection, firstSubVertex, firstSubVertex+numSubVertices);CHKERRQ(ierr);
2407     for (v = 0; v < numSubVertices; ++v) {
2408       const PetscInt vertex    = subVertices[v];
2409       const PetscInt subvertex = firstSubVertex+v;
2410       PetscInt       dof;
2411 
2412       ierr = PetscSectionGetDof(coordSection, vertex, &dof);CHKERRQ(ierr);
2413       ierr = PetscSectionSetDof(subCoordSection, subvertex, dof);CHKERRQ(ierr);
2414       ierr = PetscSectionSetFieldDof(subCoordSection, subvertex, 0, dof);CHKERRQ(ierr);
2415     }
2416     ierr = PetscSectionSetUp(subCoordSection);CHKERRQ(ierr);
2417     ierr = PetscSectionGetStorageSize(subCoordSection, &coordSize);CHKERRQ(ierr);
2418     ierr = VecCreate(comm, &subCoordinates);CHKERRQ(ierr);
2419     ierr = VecSetSizes(subCoordinates, coordSize, PETSC_DETERMINE);CHKERRQ(ierr);
2420     ierr = VecSetType(subCoordinates,dm->vectype);CHKERRQ(ierr);
2421     ierr = VecGetArray(coordinates,    &coords);CHKERRQ(ierr);
2422     ierr = VecGetArray(subCoordinates, &subCoords);CHKERRQ(ierr);
2423     for (v = 0; v < numSubVertices; ++v) {
2424       const PetscInt vertex    = subVertices[v];
2425       const PetscInt subvertex = firstSubVertex+v;
2426       PetscInt       dof, off, sdof, soff, d;
2427 
2428       ierr = PetscSectionGetDof(coordSection, vertex, &dof);CHKERRQ(ierr);
2429       ierr = PetscSectionGetOffset(coordSection, vertex, &off);CHKERRQ(ierr);
2430       ierr = PetscSectionGetDof(subCoordSection, subvertex, &sdof);CHKERRQ(ierr);
2431       ierr = PetscSectionGetOffset(subCoordSection, subvertex, &soff);CHKERRQ(ierr);
2432       if (dof != sdof) SETERRQ4(comm, PETSC_ERR_PLIB, "Coordinate dimension %d on subvertex %d, vertex %d should be %d", sdof, subvertex, vertex, dof);
2433       for (d = 0; d < dof; ++d) subCoords[soff+d] = coords[off+d];
2434     }
2435     ierr = VecRestoreArray(coordinates,    &coords);CHKERRQ(ierr);
2436     ierr = VecRestoreArray(subCoordinates, &subCoords);CHKERRQ(ierr);
2437     ierr = DMSetCoordinatesLocal(subdm, subCoordinates);CHKERRQ(ierr);
2438     ierr = VecDestroy(&subCoordinates);CHKERRQ(ierr);
2439   }
2440   /* Build SF */
2441   CHKMEMQ;
2442   {
2443     PetscSF            sfPoint, sfPointSub;
2444     const PetscSFNode *remotePoints;
2445     PetscSFNode       *sremotePoints, *newLocalPoints, *newOwners;
2446     const PetscInt    *localPoints;
2447     PetscInt          *slocalPoints;
2448     PetscInt           numRoots, numLeaves, numSubRoots = numSubCells+numSubFaces+numSubVertices, numSubLeaves = 0, l, sl, ll, pStart, pEnd, p, vStart, vEnd;
2449     PetscMPIInt        rank;
2450 
2451     ierr = MPI_Comm_rank(PetscObjectComm((PetscObject) dm), &rank);CHKERRQ(ierr);
2452     ierr = DMGetPointSF(dm, &sfPoint);CHKERRQ(ierr);
2453     ierr = DMGetPointSF(subdm, &sfPointSub);CHKERRQ(ierr);
2454     ierr = DMPlexGetChart(dm, &pStart, &pEnd);CHKERRQ(ierr);
2455     ierr = DMPlexGetDepthStratum(dm, 0, &vStart, &vEnd);CHKERRQ(ierr);
2456     ierr = PetscSFGetGraph(sfPoint, &numRoots, &numLeaves, &localPoints, &remotePoints);CHKERRQ(ierr);
2457     if (numRoots >= 0) {
2458       /* Only vertices should be shared */
2459       ierr = PetscMalloc2(pEnd-pStart,PetscSFNode,&newLocalPoints,numRoots,PetscSFNode,&newOwners);CHKERRQ(ierr);
2460       for (p = 0; p < pEnd-pStart; ++p) {
2461         newLocalPoints[p].rank  = -2;
2462         newLocalPoints[p].index = -2;
2463       }
2464       /* Set subleaves */
2465       for (l = 0; l < numLeaves; ++l) {
2466         const PetscInt point    = localPoints[l];
2467         const PetscInt subPoint = DMPlexFilterPoint_Internal(point, firstSubVertex, numSubVertices, subVertices);
2468 
2469         if ((point < vStart) && (point >= vEnd)) SETERRQ1(PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Should not be mapping anything but vertices, %d", point);
2470         if (subPoint < 0) continue;
2471         newLocalPoints[point-pStart].rank  = rank;
2472         newLocalPoints[point-pStart].index = subPoint;
2473         ++numSubLeaves;
2474       }
2475       /* Must put in owned subpoints */
2476       for (p = pStart; p < pEnd; ++p) {
2477         const PetscInt subPoint = DMPlexFilterPoint_Internal(p, firstSubVertex, numSubVertices, subVertices);
2478 
2479         if (subPoint < 0) {
2480           newOwners[p-pStart].rank  = -3;
2481           newOwners[p-pStart].index = -3;
2482         } else {
2483           newOwners[p-pStart].rank  = rank;
2484           newOwners[p-pStart].index = subPoint;
2485         }
2486       }
2487       ierr = PetscSFReduceBegin(sfPoint, MPIU_2INT, newLocalPoints, newOwners, MPI_MAXLOC);CHKERRQ(ierr);
2488       ierr = PetscSFReduceEnd(sfPoint, MPIU_2INT, newLocalPoints, newOwners, MPI_MAXLOC);CHKERRQ(ierr);
2489       ierr = PetscSFBcastBegin(sfPoint, MPIU_2INT, newOwners, newLocalPoints);CHKERRQ(ierr);
2490       ierr = PetscSFBcastEnd(sfPoint, MPIU_2INT, newOwners, newLocalPoints);CHKERRQ(ierr);
2491       ierr = PetscMalloc(numSubLeaves * sizeof(PetscInt),    &slocalPoints);CHKERRQ(ierr);
2492       ierr = PetscMalloc(numSubLeaves * sizeof(PetscSFNode), &sremotePoints);CHKERRQ(ierr);
2493       for (l = 0, sl = 0, ll = 0; l < numLeaves; ++l) {
2494         const PetscInt point    = localPoints[l];
2495         const PetscInt subPoint = DMPlexFilterPoint_Internal(point, firstSubVertex, numSubVertices, subVertices);
2496 
2497         if (subPoint < 0) continue;
2498         if (newLocalPoints[point].rank == rank) {++ll; continue;}
2499         slocalPoints[sl]        = subPoint;
2500         sremotePoints[sl].rank  = newLocalPoints[point].rank;
2501         sremotePoints[sl].index = newLocalPoints[point].index;
2502         if (sremotePoints[sl].rank  < 0) SETERRQ1(PETSC_COMM_SELF, PETSC_ERR_PLIB, "Invalid remote rank for local point %d", point);
2503         if (sremotePoints[sl].index < 0) SETERRQ1(PETSC_COMM_SELF, PETSC_ERR_PLIB, "Invalid remote subpoint for local point %d", point);
2504         ++sl;
2505       }
2506       ierr = PetscFree2(newLocalPoints,newOwners);CHKERRQ(ierr);
2507       if (sl + ll != numSubLeaves) SETERRQ3(PETSC_COMM_SELF, PETSC_ERR_PLIB, "Mismatch in number of subleaves %d + %d != %d", sl, ll, numSubLeaves);
2508       ierr = PetscSFSetGraph(sfPointSub, numSubRoots, sl, slocalPoints, PETSC_OWN_POINTER, sremotePoints, PETSC_OWN_POINTER);CHKERRQ(ierr);
2509     }
2510   }
2511   CHKMEMQ;
2512   /* Cleanup */
2513   if (subvertexIS) {ierr = ISRestoreIndices(subvertexIS, &subVertices);CHKERRQ(ierr);}
2514   ierr = ISDestroy(&subvertexIS);CHKERRQ(ierr);
2515   ierr = PetscFree(subCells);CHKERRQ(ierr);
2516   PetscFunctionReturn(0);
2517 }
2518 
2519 #undef __FUNCT__
2520 #define __FUNCT__ "DMPlexCreateCohesiveSubmesh_Interpolated"
2521 static PetscErrorCode DMPlexCreateCohesiveSubmesh_Interpolated(DM dm, PetscBool hasLagrange, const char label[], PetscInt value, DM subdm)
2522 {
2523   MPI_Comm         comm;
2524   DMLabel          subpointMap;
2525   IS              *subpointIS;
2526   const PetscInt **subpoints;
2527   PetscInt        *numSubPoints, *firstSubPoint, *coneNew;
2528   PetscInt         totSubPoints = 0, maxConeSize, dim, p, d, v;
2529   PetscErrorCode   ierr;
2530 
2531   PetscFunctionBegin;
2532   ierr = PetscObjectGetComm((PetscObject)dm,&comm);CHKERRQ(ierr);
2533   /* Create subpointMap which marks the submesh */
2534   ierr = DMLabelCreate("subpoint_map", &subpointMap);CHKERRQ(ierr);
2535   ierr = DMPlexSetSubpointMap(subdm, subpointMap);CHKERRQ(ierr);
2536   ierr = DMLabelDestroy(&subpointMap);CHKERRQ(ierr);
2537   ierr = DMPlexMarkCohesiveSubmesh_Interpolated(dm, hasLagrange, label, value, subpointMap, subdm);CHKERRQ(ierr);
2538   /* Setup chart */
2539   ierr = DMPlexGetDimension(dm, &dim);CHKERRQ(ierr);
2540   ierr = PetscMalloc4(dim+1,PetscInt,&numSubPoints,dim+1,PetscInt,&firstSubPoint,dim+1,IS,&subpointIS,dim+1,const PetscInt *,&subpoints);CHKERRQ(ierr);
2541   for (d = 0; d <= dim; ++d) {
2542     ierr = DMLabelGetStratumSize(subpointMap, d, &numSubPoints[d]);CHKERRQ(ierr);
2543     totSubPoints += numSubPoints[d];
2544   }
2545   ierr = DMPlexSetChart(subdm, 0, totSubPoints);CHKERRQ(ierr);
2546   ierr = DMPlexSetVTKCellHeight(subdm, 1);CHKERRQ(ierr);
2547   /* Set cone sizes */
2548   firstSubPoint[dim] = 0;
2549   firstSubPoint[0]   = firstSubPoint[dim] + numSubPoints[dim];
2550   if (dim > 1) {firstSubPoint[dim-1] = firstSubPoint[0]     + numSubPoints[0];}
2551   if (dim > 2) {firstSubPoint[dim-2] = firstSubPoint[dim-1] + numSubPoints[dim-1];}
2552   for (d = 0; d <= dim; ++d) {
2553     ierr = DMLabelGetStratumIS(subpointMap, d, &subpointIS[d]);CHKERRQ(ierr);
2554     ierr = ISGetIndices(subpointIS[d], &subpoints[d]);CHKERRQ(ierr);
2555   }
2556   for (d = 0; d <= dim; ++d) {
2557     for (p = 0; p < numSubPoints[d]; ++p) {
2558       const PetscInt  point    = subpoints[d][p];
2559       const PetscInt  subpoint = firstSubPoint[d] + p;
2560       const PetscInt *cone;
2561       PetscInt        coneSize, coneSizeNew, c, val;
2562 
2563       ierr = DMPlexGetConeSize(dm, point, &coneSize);CHKERRQ(ierr);
2564       ierr = DMPlexSetConeSize(subdm, subpoint, coneSize);CHKERRQ(ierr);
2565       if (d == dim) {
2566         ierr = DMPlexGetCone(dm, point, &cone);CHKERRQ(ierr);
2567         for (c = 0, coneSizeNew = 0; c < coneSize; ++c) {
2568           ierr = DMLabelGetValue(subpointMap, cone[c], &val);CHKERRQ(ierr);
2569           if (val >= 0) coneSizeNew++;
2570         }
2571         ierr = DMPlexSetConeSize(subdm, subpoint, coneSizeNew);CHKERRQ(ierr);
2572       }
2573     }
2574   }
2575   ierr = DMSetUp(subdm);CHKERRQ(ierr);
2576   /* Set cones */
2577   ierr = DMPlexGetMaxSizes(dm, &maxConeSize, NULL);CHKERRQ(ierr);
2578   ierr = PetscMalloc(maxConeSize * sizeof(PetscInt), &coneNew);CHKERRQ(ierr);
2579   for (d = 0; d <= dim; ++d) {
2580     for (p = 0; p < numSubPoints[d]; ++p) {
2581       const PetscInt  point    = subpoints[d][p];
2582       const PetscInt  subpoint = firstSubPoint[d] + p;
2583       const PetscInt *cone;
2584       PetscInt        coneSize, subconeSize, coneSizeNew, c, subc;
2585 
2586       ierr = DMPlexGetConeSize(dm, point, &coneSize);CHKERRQ(ierr);
2587       ierr = DMPlexGetConeSize(subdm, subpoint, &subconeSize);CHKERRQ(ierr);
2588       ierr = DMPlexGetCone(dm, point, &cone);CHKERRQ(ierr);
2589       for (c = 0, coneSizeNew = 0; c < coneSize; ++c) {
2590         ierr = PetscFindInt(cone[c], numSubPoints[d-1], subpoints[d-1], &subc);CHKERRQ(ierr);
2591         if (subc >= 0) coneNew[coneSizeNew++] = firstSubPoint[d-1] + subc;
2592       }
2593       if (coneSizeNew != subconeSize) SETERRQ2(comm, PETSC_ERR_PLIB, "Number of cone points located %d does not match subcone size %d", coneSizeNew, subconeSize);
2594       ierr = DMPlexSetCone(subdm, subpoint, coneNew);CHKERRQ(ierr);
2595     }
2596   }
2597   ierr = PetscFree(coneNew);CHKERRQ(ierr);
2598   ierr = DMPlexSymmetrize(subdm);CHKERRQ(ierr);
2599   ierr = DMPlexStratify(subdm);CHKERRQ(ierr);
2600   /* Build coordinates */
2601   {
2602     PetscSection coordSection, subCoordSection;
2603     Vec          coordinates, subCoordinates;
2604     PetscScalar *coords, *subCoords;
2605     PetscInt     numComp, coordSize;
2606 
2607     ierr = DMPlexGetCoordinateSection(dm, &coordSection);CHKERRQ(ierr);
2608     ierr = DMGetCoordinatesLocal(dm, &coordinates);CHKERRQ(ierr);
2609     ierr = DMPlexGetCoordinateSection(subdm, &subCoordSection);CHKERRQ(ierr);
2610     ierr = PetscSectionSetNumFields(subCoordSection, 1);CHKERRQ(ierr);
2611     ierr = PetscSectionGetFieldComponents(coordSection, 0, &numComp);CHKERRQ(ierr);
2612     ierr = PetscSectionSetFieldComponents(subCoordSection, 0, numComp);CHKERRQ(ierr);
2613     ierr = PetscSectionSetChart(subCoordSection, firstSubPoint[0], firstSubPoint[0]+numSubPoints[0]);CHKERRQ(ierr);
2614     for (v = 0; v < numSubPoints[0]; ++v) {
2615       const PetscInt vertex    = subpoints[0][v];
2616       const PetscInt subvertex = firstSubPoint[0]+v;
2617       PetscInt       dof;
2618 
2619       ierr = PetscSectionGetDof(coordSection, vertex, &dof);CHKERRQ(ierr);
2620       ierr = PetscSectionSetDof(subCoordSection, subvertex, dof);CHKERRQ(ierr);
2621       ierr = PetscSectionSetFieldDof(subCoordSection, subvertex, 0, dof);CHKERRQ(ierr);
2622     }
2623     ierr = PetscSectionSetUp(subCoordSection);CHKERRQ(ierr);
2624     ierr = PetscSectionGetStorageSize(subCoordSection, &coordSize);CHKERRQ(ierr);
2625     ierr = VecCreate(comm, &subCoordinates);CHKERRQ(ierr);
2626     ierr = VecSetSizes(subCoordinates, coordSize, PETSC_DETERMINE);CHKERRQ(ierr);
2627     ierr = VecSetType(subCoordinates,dm->vectype);CHKERRQ(ierr);
2628     ierr = VecGetArray(coordinates,    &coords);CHKERRQ(ierr);
2629     ierr = VecGetArray(subCoordinates, &subCoords);CHKERRQ(ierr);
2630     for (v = 0; v < numSubPoints[0]; ++v) {
2631       const PetscInt vertex    = subpoints[0][v];
2632       const PetscInt subvertex = firstSubPoint[0]+v;
2633       PetscInt dof, off, sdof, soff, d;
2634 
2635       ierr = PetscSectionGetDof(coordSection, vertex, &dof);CHKERRQ(ierr);
2636       ierr = PetscSectionGetOffset(coordSection, vertex, &off);CHKERRQ(ierr);
2637       ierr = PetscSectionGetDof(subCoordSection, subvertex, &sdof);CHKERRQ(ierr);
2638       ierr = PetscSectionGetOffset(subCoordSection, subvertex, &soff);CHKERRQ(ierr);
2639       if (dof != sdof) SETERRQ4(comm, PETSC_ERR_PLIB, "Coordinate dimension %d on subvertex %d, vertex %d should be %d", sdof, subvertex, vertex, dof);
2640       for (d = 0; d < dof; ++d) subCoords[soff+d] = coords[off+d];
2641     }
2642     ierr = VecRestoreArray(coordinates,    &coords);CHKERRQ(ierr);
2643     ierr = VecRestoreArray(subCoordinates, &subCoords);CHKERRQ(ierr);
2644     ierr = DMSetCoordinatesLocal(subdm, subCoordinates);CHKERRQ(ierr);
2645     ierr = VecDestroy(&subCoordinates);CHKERRQ(ierr);
2646   }
2647   /* Cleanup */
2648   for (d = 0; d <= dim; ++d) {
2649     ierr = ISRestoreIndices(subpointIS[d], &subpoints[d]);CHKERRQ(ierr);
2650     ierr = ISDestroy(&subpointIS[d]);CHKERRQ(ierr);
2651   }
2652   ierr = PetscFree4(numSubPoints,firstSubPoint,subpointIS,subpoints);CHKERRQ(ierr);
2653   PetscFunctionReturn(0);
2654 }
2655 
2656 #undef __FUNCT__
2657 #define __FUNCT__ "DMPlexCreateCohesiveSubmesh"
2658 /*
2659   DMPlexCreateCohesiveSubmesh - Extract from a mesh with cohesive cells the hypersurface defined by one face of the cells. Optionally, a Label an be given to restrict the cells.
2660 
2661   Input Parameters:
2662 + dm          - The original mesh
2663 . hasLagrange - The mesh has Lagrange unknowns in the cohesive cells
2664 . label       - A label name, or PETSC_NULL
2665 - value  - A label value
2666 
2667   Output Parameter:
2668 . subdm - The surface mesh
2669 
2670   Note: This function produces a DMLabel mapping original points in the submesh to their depth. This can be obtained using DMPlexGetSubpointMap().
2671 
2672   Level: developer
2673 
2674 .seealso: DMPlexGetSubpointMap(), DMPlexCreateSubmesh()
2675 */
2676 PetscErrorCode DMPlexCreateCohesiveSubmesh(DM dm, PetscBool hasLagrange, const char label[], PetscInt value, DM *subdm)
2677 {
2678   PetscInt       dim, depth;
2679   PetscErrorCode ierr;
2680 
2681   PetscFunctionBegin;
2682   PetscValidHeaderSpecific(dm, DM_CLASSID, 1);
2683   PetscValidPointer(subdm, 5);
2684   ierr = DMPlexGetDimension(dm, &dim);CHKERRQ(ierr);
2685   ierr = DMPlexGetDepth(dm, &depth);CHKERRQ(ierr);
2686   ierr = DMCreate(PetscObjectComm((PetscObject)dm), subdm);CHKERRQ(ierr);
2687   ierr = DMSetType(*subdm, DMPLEX);CHKERRQ(ierr);
2688   ierr = DMPlexSetDimension(*subdm, dim-1);CHKERRQ(ierr);
2689   if (depth == dim) {
2690     ierr = DMPlexCreateCohesiveSubmesh_Interpolated(dm, hasLagrange, label, value, *subdm);CHKERRQ(ierr);
2691   } else {
2692     ierr = DMPlexCreateCohesiveSubmesh_Uninterpolated(dm, hasLagrange, label, value, *subdm);CHKERRQ(ierr);
2693   }
2694   PetscFunctionReturn(0);
2695 }
2696 
2697 #undef __FUNCT__
2698 #define __FUNCT__ "DMPlexGetSubpointMap"
2699 /*@
2700   DMPlexGetSubpointMap - Returns a DMLabel with point dimension as values
2701 
2702   Input Parameter:
2703 . dm - The submesh DM
2704 
2705   Output Parameter:
2706 . subpointMap - The DMLabel of all the points from the original mesh in this submesh, or NULL if this is not a submesh
2707 
2708   Level: developer
2709 
2710 .seealso: DMPlexCreateSubmesh(), DMPlexCreateSubpointIS()
2711 @*/
2712 PetscErrorCode DMPlexGetSubpointMap(DM dm, DMLabel *subpointMap)
2713 {
2714   DM_Plex *mesh = (DM_Plex*) dm->data;
2715 
2716   PetscFunctionBegin;
2717   PetscValidHeaderSpecific(dm, DM_CLASSID, 1);
2718   PetscValidPointer(subpointMap, 2);
2719   *subpointMap = mesh->subpointMap;
2720   PetscFunctionReturn(0);
2721 }
2722 
2723 #undef __FUNCT__
2724 #define __FUNCT__ "DMPlexSetSubpointMap"
2725 /* Note: Should normally not be called by the user, since it is set in DMPlexCreateSubmesh() */
2726 PetscErrorCode DMPlexSetSubpointMap(DM dm, DMLabel subpointMap)
2727 {
2728   DM_Plex       *mesh = (DM_Plex *) dm->data;
2729   DMLabel        tmp;
2730   PetscErrorCode ierr;
2731 
2732   PetscFunctionBegin;
2733   PetscValidHeaderSpecific(dm, DM_CLASSID, 1);
2734   tmp  = mesh->subpointMap;
2735   mesh->subpointMap = subpointMap;
2736   ++mesh->subpointMap->refct;
2737   ierr = DMLabelDestroy(&tmp);CHKERRQ(ierr);
2738   PetscFunctionReturn(0);
2739 }
2740 
2741 #undef __FUNCT__
2742 #define __FUNCT__ "DMPlexCreateSubpointIS"
2743 /*@
2744   DMPlexCreateSubpointIS - Creates an IS covering the entire subdm chart with the original points as data
2745 
2746   Input Parameter:
2747 . dm - The submesh DM
2748 
2749   Output Parameter:
2750 . subpointIS - The IS of all the points from the original mesh in this submesh, or NULL if this is not a submesh
2751 
2752   Note: This is IS is guaranteed to be sorted by the construction of the submesh
2753 
2754   Level: developer
2755 
2756 .seealso: DMPlexCreateSubmesh(), DMPlexGetSubpointMap()
2757 @*/
2758 PetscErrorCode DMPlexCreateSubpointIS(DM dm, IS *subpointIS)
2759 {
2760   MPI_Comm        comm;
2761   DMLabel         subpointMap;
2762   IS              is;
2763   const PetscInt *opoints;
2764   PetscInt       *points, *depths;
2765   PetscInt        depth, depStart, depEnd, d, pStart, pEnd, p, n, off;
2766   PetscErrorCode  ierr;
2767 
2768   PetscFunctionBegin;
2769   PetscValidHeaderSpecific(dm, DM_CLASSID, 1);
2770   PetscValidPointer(subpointIS, 2);
2771   ierr = PetscObjectGetComm((PetscObject)dm,&comm);CHKERRQ(ierr);
2772   *subpointIS = NULL;
2773   ierr = DMPlexGetSubpointMap(dm, &subpointMap);CHKERRQ(ierr);
2774   ierr = DMPlexGetDepth(dm, &depth);CHKERRQ(ierr);
2775   if (subpointMap && depth >= 0) {
2776     ierr = DMPlexGetChart(dm, &pStart, &pEnd);CHKERRQ(ierr);
2777     if (pStart) SETERRQ1(comm, PETSC_ERR_ARG_WRONG, "Submeshes must start the point numbering at 0, not %d", pStart);
2778     ierr = DMGetWorkArray(dm, depth+1, PETSC_INT, &depths);CHKERRQ(ierr);
2779     depths[0] = depth;
2780     depths[1] = 0;
2781     for(d = 2; d <= depth; ++d) {depths[d] = depth+1 - d;}
2782     ierr = PetscMalloc(pEnd * sizeof(PetscInt), &points);CHKERRQ(ierr);
2783     for(d = 0, off = 0; d <= depth; ++d) {
2784       const PetscInt dep = depths[d];
2785 
2786       ierr = DMPlexGetDepthStratum(dm, dep, &depStart, &depEnd);CHKERRQ(ierr);
2787       ierr = DMLabelGetStratumSize(subpointMap, dep, &n);CHKERRQ(ierr);
2788       if (((d < 2) && (depth > 1)) || (d == 1)) { /* Only check vertices and cells for now since the map is broken for others */
2789         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);
2790       } else {
2791         if (!n) {
2792           if (d == 0) {
2793             /* Missing cells */
2794             for(p = 0; p < depEnd-depStart; ++p, ++off) points[off] = -1;
2795           } else {
2796             /* Missing faces */
2797             for(p = 0; p < depEnd-depStart; ++p, ++off) points[off] = PETSC_MAX_INT;
2798           }
2799         }
2800       }
2801       if (n) {
2802         ierr = DMLabelGetStratumIS(subpointMap, dep, &is);CHKERRQ(ierr);
2803         ierr = ISGetIndices(is, &opoints);CHKERRQ(ierr);
2804         for(p = 0; p < n; ++p, ++off) points[off] = opoints[p];
2805         ierr = ISRestoreIndices(is, &opoints);CHKERRQ(ierr);
2806         ierr = ISDestroy(&is);CHKERRQ(ierr);
2807       }
2808     }
2809     ierr = DMRestoreWorkArray(dm, depth+1, PETSC_INT, &depths);CHKERRQ(ierr);
2810     if (off != pEnd) SETERRQ2(comm, PETSC_ERR_ARG_WRONG, "The number of mapped submesh points %d should be %d", off, pEnd);
2811     ierr = ISCreateGeneral(PETSC_COMM_SELF, pEnd, points, PETSC_OWN_POINTER, subpointIS);CHKERRQ(ierr);
2812   }
2813   PetscFunctionReturn(0);
2814 }
2815