xref: /petsc/src/dm/impls/plex/plexsubmesh.c (revision 47946fd8e6647c5067cb75110e1ed3a9dfc16047)
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 = VecSetFromOptions(newCoordinates);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   PetscMPIInt        numProcs;
253   PetscErrorCode     ierr;
254 
255   PetscFunctionBegin;
256   ierr = DMPlexGetDepth(dm, &depth);CHKERRQ(ierr);
257   ierr = PetscMalloc((depth+1) * sizeof(PetscInt), &depthEnd);CHKERRQ(ierr);
258   for (d = 0; d <= depth; ++d) {
259     totShift += depthShift[d];
260     ierr      = DMPlexGetDepthStratum(dm, d, NULL, &depthEnd[d]);CHKERRQ(ierr);
261   }
262   /* Step 9: Convert pointSF */
263   ierr = MPI_Comm_size(PetscObjectComm((PetscObject)dm), &numProcs);CHKERRQ(ierr);
264   ierr = DMGetPointSF(dm, &sfPoint);CHKERRQ(ierr);
265   ierr = DMGetPointSF(dmNew, &sfPointNew);CHKERRQ(ierr);
266   ierr = DMPlexGetChart(dm, &pStart, &pEnd);CHKERRQ(ierr);
267   ierr = PetscSFGetGraph(sfPoint, &numRoots, &numLeaves, &localPoints, &remotePoints);CHKERRQ(ierr);
268   if (numRoots >= 0) {
269     ierr = PetscMalloc2(numRoots,PetscInt,&newLocation,pEnd-pStart,PetscInt,&newRemoteLocation);CHKERRQ(ierr);
270     for (l=0; l<numRoots; l++) newLocation[l] = DMPlexShiftPoint_Internal(l, depth, depthEnd, depthShift);
271     ierr = PetscSFBcastBegin(sfPoint, MPIU_INT, newLocation, newRemoteLocation);CHKERRQ(ierr);
272     ierr = PetscSFBcastEnd(sfPoint, MPIU_INT, newLocation, newRemoteLocation);CHKERRQ(ierr);
273     ierr = PetscMalloc(numLeaves * sizeof(PetscInt),    &glocalPoints);CHKERRQ(ierr);
274     ierr = PetscMalloc(numLeaves * sizeof(PetscSFNode), &gremotePoints);CHKERRQ(ierr);
275     for (l = 0; l < numLeaves; ++l) {
276       glocalPoints[l]        = DMPlexShiftPoint_Internal(localPoints[l], depth, depthEnd, depthShift);
277       gremotePoints[l].rank  = remotePoints[l].rank;
278       gremotePoints[l].index = newRemoteLocation[localPoints[l]];
279     }
280     ierr = PetscFree2(newLocation,newRemoteLocation);CHKERRQ(ierr);
281     ierr = PetscSFSetGraph(sfPointNew, numRoots + totShift, numLeaves, glocalPoints, PETSC_OWN_POINTER, gremotePoints, PETSC_OWN_POINTER);CHKERRQ(ierr);
282   }
283   ierr = PetscFree(depthEnd);CHKERRQ(ierr);
284   PetscFunctionReturn(0);
285 }
286 
287 #undef __FUNCT__
288 #define __FUNCT__ "DMPlexShiftLabels_Internal"
289 static PetscErrorCode DMPlexShiftLabels_Internal(DM dm, PetscInt depthShift[], DM dmNew)
290 {
291   PetscSF            sfPoint;
292   DMLabel            vtkLabel, ghostLabel;
293   PetscInt          *depthEnd;
294   const PetscSFNode *leafRemote;
295   const PetscInt    *leafLocal;
296   PetscInt           depth = 0, d, numLeaves, numLabels, l, cStart, cEnd, c, fStart, fEnd, f;
297   PetscMPIInt        rank;
298   PetscErrorCode     ierr;
299 
300   PetscFunctionBegin;
301   ierr = DMPlexGetDepth(dm, &depth);CHKERRQ(ierr);
302   ierr = PetscMalloc((depth+1) * sizeof(PetscInt), &depthEnd);CHKERRQ(ierr);
303   for (d = 0; d <= depth; ++d) {
304     ierr = DMPlexGetDepthStratum(dm, d, NULL, &depthEnd[d]);CHKERRQ(ierr);
305   }
306   /* Step 10: Convert labels */
307   ierr = DMPlexGetNumLabels(dm, &numLabels);CHKERRQ(ierr);
308   for (l = 0; l < numLabels; ++l) {
309     DMLabel         label, newlabel;
310     const char     *lname;
311     PetscBool       isDepth;
312     IS              valueIS;
313     const PetscInt *values;
314     PetscInt        numValues, val;
315 
316     ierr = DMPlexGetLabelName(dm, l, &lname);CHKERRQ(ierr);
317     ierr = PetscStrcmp(lname, "depth", &isDepth);CHKERRQ(ierr);
318     if (isDepth) continue;
319     ierr = DMPlexCreateLabel(dmNew, lname);CHKERRQ(ierr);
320     ierr = DMPlexGetLabel(dm, lname, &label);CHKERRQ(ierr);
321     ierr = DMPlexGetLabel(dmNew, lname, &newlabel);CHKERRQ(ierr);
322     ierr = DMLabelGetValueIS(label, &valueIS);CHKERRQ(ierr);
323     ierr = ISGetLocalSize(valueIS, &numValues);CHKERRQ(ierr);
324     ierr = ISGetIndices(valueIS, &values);CHKERRQ(ierr);
325     for (val = 0; val < numValues; ++val) {
326       IS              pointIS;
327       const PetscInt *points;
328       PetscInt        numPoints, p;
329 
330       ierr = DMLabelGetStratumIS(label, values[val], &pointIS);CHKERRQ(ierr);
331       ierr = ISGetLocalSize(pointIS, &numPoints);CHKERRQ(ierr);
332       ierr = ISGetIndices(pointIS, &points);CHKERRQ(ierr);
333       for (p = 0; p < numPoints; ++p) {
334         const PetscInt newpoint = DMPlexShiftPoint_Internal(points[p], depth, depthEnd, depthShift);
335 
336         ierr = DMLabelSetValue(newlabel, newpoint, values[val]);CHKERRQ(ierr);
337       }
338       ierr = ISRestoreIndices(pointIS, &points);CHKERRQ(ierr);
339       ierr = ISDestroy(&pointIS);CHKERRQ(ierr);
340     }
341     ierr = ISRestoreIndices(valueIS, &values);CHKERRQ(ierr);
342     ierr = ISDestroy(&valueIS);CHKERRQ(ierr);
343   }
344   ierr = PetscFree(depthEnd);CHKERRQ(ierr);
345   /* Step 11: Make label for output (vtk) and to mark ghost points (ghost) */
346   ierr = MPI_Comm_rank(PetscObjectComm((PetscObject)dm), &rank);CHKERRQ(ierr);
347   ierr = DMGetPointSF(dm, &sfPoint);CHKERRQ(ierr);
348   ierr = DMPlexGetHeightStratum(dm, 0, &cStart, &cEnd);CHKERRQ(ierr);
349   ierr = PetscSFGetGraph(sfPoint, NULL, &numLeaves, &leafLocal, &leafRemote);CHKERRQ(ierr);
350   ierr = DMPlexCreateLabel(dmNew, "vtk");CHKERRQ(ierr);
351   ierr = DMPlexCreateLabel(dmNew, "ghost");CHKERRQ(ierr);
352   ierr = DMPlexGetLabel(dmNew, "vtk", &vtkLabel);CHKERRQ(ierr);
353   ierr = DMPlexGetLabel(dmNew, "ghost", &ghostLabel);CHKERRQ(ierr);
354   for (l = 0, c = cStart; l < numLeaves && c < cEnd; ++l, ++c) {
355     for (; c < leafLocal[l] && c < cEnd; ++c) {
356       ierr = DMLabelSetValue(vtkLabel, c, 1);CHKERRQ(ierr);
357     }
358     if (leafLocal[l] >= cEnd) break;
359     if (leafRemote[l].rank == rank) {
360       ierr = DMLabelSetValue(vtkLabel, c, 1);CHKERRQ(ierr);
361     } else {
362       ierr = DMLabelSetValue(ghostLabel, c, 2);CHKERRQ(ierr);
363     }
364   }
365   for (; c < cEnd; ++c) {
366     ierr = DMLabelSetValue(vtkLabel, c, 1);CHKERRQ(ierr);
367   }
368   if (0) {
369     ierr = PetscViewerASCIISynchronizedAllow(PETSC_VIEWER_STDOUT_WORLD, PETSC_TRUE);CHKERRQ(ierr);
370     ierr = DMLabelView(vtkLabel, PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
371     ierr = PetscViewerFlush(PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
372   }
373   ierr = DMPlexGetHeightStratum(dmNew, 1, &fStart, &fEnd);CHKERRQ(ierr);
374   for (f = fStart; f < fEnd; ++f) {
375     PetscInt numCells;
376 
377     ierr = DMPlexGetSupportSize(dmNew, f, &numCells);CHKERRQ(ierr);
378     if (numCells < 2) {
379       ierr = DMLabelSetValue(ghostLabel, f, 1);CHKERRQ(ierr);
380     } else {
381       const PetscInt *cells = NULL;
382       PetscInt        vA, vB;
383 
384       ierr = DMPlexGetSupport(dmNew, f, &cells);CHKERRQ(ierr);
385       ierr = DMLabelGetValue(vtkLabel, cells[0], &vA);CHKERRQ(ierr);
386       ierr = DMLabelGetValue(vtkLabel, cells[1], &vB);CHKERRQ(ierr);
387       if (!vA && !vB) {ierr = DMLabelSetValue(ghostLabel, f, 1);CHKERRQ(ierr);}
388     }
389   }
390   if (0) {
391     ierr = PetscViewerASCIISynchronizedAllow(PETSC_VIEWER_STDOUT_WORLD, PETSC_TRUE);CHKERRQ(ierr);
392     ierr = DMLabelView(ghostLabel, PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
393     ierr = PetscViewerFlush(PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
394   }
395   PetscFunctionReturn(0);
396 }
397 
398 #undef __FUNCT__
399 #define __FUNCT__ "DMPlexConstructGhostCells_Internal"
400 static PetscErrorCode DMPlexConstructGhostCells_Internal(DM dm, DMLabel label, PetscInt *numGhostCells, DM gdm)
401 {
402   IS              valueIS;
403   const PetscInt *values;
404   PetscInt       *depthShift;
405   PetscInt        depth = 0, numFS, fs, ghostCell, cEnd, c;
406   PetscErrorCode  ierr;
407 
408   PetscFunctionBegin;
409   /* Count ghost cells */
410   ierr = DMLabelGetValueIS(label, &valueIS);CHKERRQ(ierr);
411   ierr = ISGetLocalSize(valueIS, &numFS);CHKERRQ(ierr);
412   ierr = ISGetIndices(valueIS, &values);CHKERRQ(ierr);
413 
414   *numGhostCells = 0;
415   for (fs = 0; fs < numFS; ++fs) {
416     PetscInt numBdFaces;
417 
418     ierr = DMLabelGetStratumSize(label, values[fs], &numBdFaces);CHKERRQ(ierr);
419 
420     *numGhostCells += numBdFaces;
421   }
422   ierr = DMPlexGetDepth(dm, &depth);CHKERRQ(ierr);
423   ierr = PetscMalloc((depth+1) * sizeof(PetscInt), &depthShift);CHKERRQ(ierr);
424   ierr = PetscMemzero(depthShift, (depth+1) * sizeof(PetscInt));CHKERRQ(ierr);
425   if (depth >= 0) depthShift[depth] = *numGhostCells;
426   ierr = DMPlexShiftSizes_Internal(dm, depthShift, gdm);CHKERRQ(ierr);
427   /* Step 3: Set cone/support sizes for new points */
428   ierr = DMPlexGetHeightStratum(dm, 0, NULL, &cEnd);CHKERRQ(ierr);
429   for (c = cEnd; c < cEnd + *numGhostCells; ++c) {
430     ierr = DMPlexSetConeSize(gdm, c, 1);CHKERRQ(ierr);
431   }
432   for (fs = 0; fs < numFS; ++fs) {
433     IS              faceIS;
434     const PetscInt *faces;
435     PetscInt        numFaces, f;
436 
437     ierr = DMLabelGetStratumIS(label, values[fs], &faceIS);CHKERRQ(ierr);
438     ierr = ISGetLocalSize(faceIS, &numFaces);CHKERRQ(ierr);
439     ierr = ISGetIndices(faceIS, &faces);CHKERRQ(ierr);
440     for (f = 0; f < numFaces; ++f) {
441       PetscInt size;
442 
443       ierr = DMPlexGetSupportSize(dm, faces[f], &size);CHKERRQ(ierr);
444       if (size != 1) SETERRQ2(PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_WRONG, "DM has boundary face %d with %d support cells", faces[f], size);
445       ierr = DMPlexSetSupportSize(gdm, faces[f] + *numGhostCells, 2);CHKERRQ(ierr);
446     }
447     ierr = ISRestoreIndices(faceIS, &faces);CHKERRQ(ierr);
448     ierr = ISDestroy(&faceIS);CHKERRQ(ierr);
449   }
450   /* Step 4: Setup ghosted DM */
451   ierr = DMSetUp(gdm);CHKERRQ(ierr);
452   ierr = DMPlexShiftPoints_Internal(dm, depthShift, gdm);CHKERRQ(ierr);
453   /* Step 6: Set cones and supports for new points */
454   ghostCell = cEnd;
455   for (fs = 0; fs < numFS; ++fs) {
456     IS              faceIS;
457     const PetscInt *faces;
458     PetscInt        numFaces, f;
459 
460     ierr = DMLabelGetStratumIS(label, values[fs], &faceIS);CHKERRQ(ierr);
461     ierr = ISGetLocalSize(faceIS, &numFaces);CHKERRQ(ierr);
462     ierr = ISGetIndices(faceIS, &faces);CHKERRQ(ierr);
463     for (f = 0; f < numFaces; ++f, ++ghostCell) {
464       PetscInt newFace = faces[f] + *numGhostCells;
465 
466       ierr = DMPlexSetCone(gdm, ghostCell, &newFace);CHKERRQ(ierr);
467       ierr = DMPlexInsertSupport(gdm, newFace, 1, ghostCell);CHKERRQ(ierr);
468     }
469     ierr = ISRestoreIndices(faceIS, &faces);CHKERRQ(ierr);
470     ierr = ISDestroy(&faceIS);CHKERRQ(ierr);
471   }
472   ierr = ISRestoreIndices(valueIS, &values);CHKERRQ(ierr);
473   ierr = ISDestroy(&valueIS);CHKERRQ(ierr);
474   /* Step 7: Stratify */
475   ierr = DMPlexStratify(gdm);CHKERRQ(ierr);
476   ierr = DMPlexShiftCoordinates_Internal(dm, depthShift, gdm);CHKERRQ(ierr);
477   ierr = DMPlexShiftSF_Internal(dm, depthShift, gdm);CHKERRQ(ierr);
478   ierr = DMPlexShiftLabels_Internal(dm, depthShift, gdm);CHKERRQ(ierr);
479   ierr = PetscFree(depthShift);CHKERRQ(ierr);
480   PetscFunctionReturn(0);
481 }
482 
483 #undef __FUNCT__
484 #define __FUNCT__ "DMPlexConstructGhostCells"
485 /*@C
486   DMPlexConstructGhostCells - Construct ghost cells which connect to every boundary face
487 
488   Collective on dm
489 
490   Input Parameters:
491 + dm - The original DM
492 - labelName - The label specifying the boundary faces, or "Face Sets" if this is NULL
493 
494   Output Parameters:
495 + numGhostCells - The number of ghost cells added to the DM
496 - dmGhosted - The new DM
497 
498   Note: If no label exists of that name, one will be created marking all boundary faces
499 
500   Level: developer
501 
502 .seealso: DMCreate()
503 */
504 PetscErrorCode DMPlexConstructGhostCells(DM dm, const char labelName[], PetscInt *numGhostCells, DM *dmGhosted)
505 {
506   DM             gdm;
507   DMLabel        label;
508   const char    *name = labelName ? labelName : "Face Sets";
509   PetscInt       dim;
510   PetscErrorCode ierr;
511 
512   PetscFunctionBegin;
513   PetscValidHeaderSpecific(dm, DM_CLASSID, 1);
514   PetscValidPointer(numGhostCells, 3);
515   PetscValidPointer(dmGhosted, 4);
516   ierr = DMCreate(PetscObjectComm((PetscObject)dm), &gdm);CHKERRQ(ierr);
517   ierr = DMSetType(gdm, DMPLEX);CHKERRQ(ierr);
518   ierr = DMPlexGetDimension(dm, &dim);CHKERRQ(ierr);
519   ierr = DMPlexSetDimension(gdm, dim);CHKERRQ(ierr);
520   ierr = DMPlexGetLabel(dm, name, &label);CHKERRQ(ierr);
521   if (!label) {
522     /* Get label for boundary faces */
523     ierr = DMPlexCreateLabel(dm, name);CHKERRQ(ierr);
524     ierr = DMPlexGetLabel(dm, name, &label);CHKERRQ(ierr);
525     ierr = DMPlexMarkBoundaryFaces(dm, label);CHKERRQ(ierr);
526   }
527   ierr = DMPlexConstructGhostCells_Internal(dm, label, numGhostCells, gdm);CHKERRQ(ierr);
528   ierr = DMSetFromOptions(gdm);CHKERRQ(ierr);
529   *dmGhosted = gdm;
530   PetscFunctionReturn(0);
531 }
532 
533 #undef __FUNCT__
534 #define __FUNCT__ "DMPlexConstructCohesiveCells_Internal"
535 static PetscErrorCode DMPlexConstructCohesiveCells_Internal(DM dm, DMLabel label, DM sdm)
536 {
537   MPI_Comm        comm;
538   IS              valueIS, *pointIS;
539   const PetscInt *values, **splitPoints;
540   PetscSection    coordSection;
541   Vec             coordinates;
542   PetscScalar    *coords;
543   PetscInt       *depthShift, *depthOffset, *pMaxNew, *numSplitPoints, *coneNew, *coneONew, *supportNew;
544   PetscInt        shift = 100, depth = 0, dep, dim, d, numSP = 0, sp, maxConeSize, maxSupportSize, numLabels, pEnd, p, v;
545   PetscErrorCode  ierr;
546 
547   PetscFunctionBegin;
548   ierr = PetscObjectGetComm((PetscObject)dm,&comm);CHKERRQ(ierr);
549   ierr = DMPlexGetDimension(dm, &dim);CHKERRQ(ierr);
550   /* Count split points and add cohesive cells */
551   if (label) {
552     ierr = DMLabelGetValueIS(label, &valueIS);CHKERRQ(ierr);
553     ierr = ISGetLocalSize(valueIS, &numSP);CHKERRQ(ierr);
554     ierr = ISGetIndices(valueIS, &values);CHKERRQ(ierr);
555   }
556   ierr = DMPlexGetDepth(dm, &depth);CHKERRQ(ierr);
557   ierr = DMPlexGetMaxSizes(dm, &maxConeSize, &maxSupportSize);CHKERRQ(ierr);
558   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);
559   ierr = PetscMalloc3(depth+1,IS,&pointIS,depth+1,PetscInt,&numSplitPoints,depth+1,const PetscInt*,&splitPoints);CHKERRQ(ierr);
560   ierr = PetscMemzero(depthShift, (depth+1) * sizeof(PetscInt));CHKERRQ(ierr);
561   for (d = 0; d <= depth; ++d) {
562     ierr              = DMPlexGetDepthStratum(dm, d, NULL, &pMaxNew[d]);CHKERRQ(ierr);
563     numSplitPoints[d] = 0;
564     splitPoints[d]    = NULL;
565     pointIS[d]        = NULL;
566   }
567   for (sp = 0; sp < numSP; ++sp) {
568     const PetscInt dep = values[sp];
569 
570     if ((dep < 0) || (dep > depth)) continue;
571     ierr = DMLabelGetStratumSize(label, dep, &depthShift[dep]);CHKERRQ(ierr);
572     ierr = DMLabelGetStratumIS(label, dep, &pointIS[dep]);CHKERRQ(ierr);
573     if (pointIS[dep]) {
574       ierr = ISGetLocalSize(pointIS[dep], &numSplitPoints[dep]);CHKERRQ(ierr);
575       ierr = ISGetIndices(pointIS[dep], &splitPoints[dep]);CHKERRQ(ierr);
576     }
577   }
578   if (depth >= 0) {
579     /* Calculate number of additional points */
580     depthShift[depth] = depthShift[depth-1]; /* There is a cohesive cell for every split face   */
581     depthShift[1]    += depthShift[0];       /* There is a cohesive edge for every split vertex */
582     /* Calculate hybrid bound for each dimension */
583     pMaxNew[0] += depthShift[depth];
584     if (depth > 1) pMaxNew[dim-1] += depthShift[depth] + depthShift[0];
585     if (depth > 2) pMaxNew[1]     += depthShift[depth] + depthShift[0] + depthShift[dim-1];
586 
587     /* Calculate point offset for each dimension */
588     depthOffset[depth] = 0;
589     depthOffset[0]     = depthOffset[depth] + depthShift[depth];
590     if (depth > 1) depthOffset[dim-1] = depthOffset[0]     + depthShift[0];
591     if (depth > 2) depthOffset[1]     = depthOffset[dim-1] + depthShift[dim-1];
592   }
593   ierr = DMPlexShiftSizes_Internal(dm, depthShift, sdm);CHKERRQ(ierr);
594   /* Step 3: Set cone/support sizes for new points */
595   for (dep = 0; dep <= depth; ++dep) {
596     for (p = 0; p < numSplitPoints[dep]; ++p) {
597       const PetscInt  oldp   = splitPoints[dep][p];
598       const PetscInt  newp   = depthOffset[dep] + oldp;
599       const PetscInt  splitp = pMaxNew[dep] + p;
600       const PetscInt *support;
601       PetscInt        coneSize, supportSize, q, e;
602 
603       ierr = DMPlexGetConeSize(dm, oldp, &coneSize);CHKERRQ(ierr);
604       ierr = DMPlexSetConeSize(sdm, splitp, coneSize);CHKERRQ(ierr);
605       ierr = DMPlexGetSupportSize(dm, oldp, &supportSize);CHKERRQ(ierr);
606       ierr = DMPlexSetSupportSize(sdm, splitp, supportSize);CHKERRQ(ierr);
607       if (dep == depth-1) {
608         const PetscInt ccell = pMaxNew[depth] + p;
609         /* Add cohesive cells, they are prisms */
610         ierr = DMPlexSetConeSize(sdm, ccell, 2 + coneSize);CHKERRQ(ierr);
611       } else if (dep == 0) {
612         const PetscInt cedge = pMaxNew[1] + (depthShift[1] - depthShift[0]) + p;
613 
614         ierr = DMPlexGetSupport(dm, oldp, &support);CHKERRQ(ierr);
615         /* Split old vertex: Edges in old split faces and new cohesive edge */
616         for (e = 0, q = 0; e < supportSize; ++e) {
617           PetscInt val;
618 
619           ierr = DMLabelGetValue(label, support[e], &val);CHKERRQ(ierr);
620           if ((val == 1) || (val == (shift + 1))) ++q;
621         }
622         ierr = DMPlexSetSupportSize(sdm, newp, q+1);CHKERRQ(ierr);
623         /* Split new vertex: Edges in new split faces and new cohesive edge */
624         for (e = 0, q = 0; e < supportSize; ++e) {
625           PetscInt val;
626 
627           ierr = DMLabelGetValue(label, support[e], &val);CHKERRQ(ierr);
628           if ((val == 1) || (val == -(shift + 1))) ++q;
629         }
630         ierr = DMPlexSetSupportSize(sdm, splitp, q+1);CHKERRQ(ierr);
631         /* Add cohesive edges */
632         ierr = DMPlexSetConeSize(sdm, cedge, 2);CHKERRQ(ierr);
633         /* Punt for now on support, you loop over closure, extract faces, check which ones are in the label */
634       } else if (dep == dim-2) {
635         ierr = DMPlexGetSupport(dm, oldp, &support);CHKERRQ(ierr);
636         /* Split old edge: Faces in positive side cells and old split faces */
637         for (e = 0, q = 0; e < supportSize; ++e) {
638           PetscInt val;
639 
640           ierr = DMLabelGetValue(label, support[e], &val);CHKERRQ(ierr);
641           if ((val == dim-1) || (val == (shift + dim-1))) ++q;
642         }
643         ierr = DMPlexSetSupportSize(sdm, newp, q);CHKERRQ(ierr);
644         /* Split new edge: Faces in negative side cells and new split faces */
645         for (e = 0, q = 0; e < supportSize; ++e) {
646           PetscInt val;
647 
648           ierr = DMLabelGetValue(label, support[e], &val);CHKERRQ(ierr);
649           if ((val == dim-1) || (val == -(shift + dim-1))) ++q;
650         }
651         ierr = DMPlexSetSupportSize(sdm, splitp, q);CHKERRQ(ierr);
652       }
653     }
654   }
655   /* Step 4: Setup split DM */
656   ierr = DMSetUp(sdm);CHKERRQ(ierr);
657   ierr = DMPlexShiftPoints_Internal(dm, depthShift, sdm);CHKERRQ(ierr);
658   /* Step 6: Set cones and supports for new points */
659   for (dep = 0; dep <= depth; ++dep) {
660     for (p = 0; p < numSplitPoints[dep]; ++p) {
661       const PetscInt  oldp   = splitPoints[dep][p];
662       const PetscInt  newp   = depthOffset[dep] + oldp;
663       const PetscInt  splitp = pMaxNew[dep] + p;
664       const PetscInt *cone, *support, *ornt;
665       PetscInt        coneSize, supportSize, q, v, e, s;
666 
667       ierr = DMPlexGetConeSize(dm, oldp, &coneSize);CHKERRQ(ierr);
668       ierr = DMPlexGetCone(dm, oldp, &cone);CHKERRQ(ierr);
669       ierr = DMPlexGetConeOrientation(dm, oldp, &ornt);CHKERRQ(ierr);
670       ierr = DMPlexGetSupportSize(dm, oldp, &supportSize);CHKERRQ(ierr);
671       ierr = DMPlexGetSupport(dm, oldp, &support);CHKERRQ(ierr);
672       if (dep == depth-1) {
673         const PetscInt  ccell = pMaxNew[depth] + p;
674         const PetscInt *supportF;
675 
676         /* Split face:       copy in old face to new face to start */
677         ierr = DMPlexGetSupport(sdm, newp,  &supportF);CHKERRQ(ierr);
678         ierr = DMPlexSetSupport(sdm, splitp, supportF);CHKERRQ(ierr);
679         /* Split old face:   old vertices/edges in cone so no change */
680         /* Split new face:   new vertices/edges in cone */
681         for (q = 0; q < coneSize; ++q) {
682           ierr = PetscFindInt(cone[q], numSplitPoints[dim-2], splitPoints[dim-2], &v);CHKERRQ(ierr);
683 
684           coneNew[2+q] = pMaxNew[dim-2] + v;
685         }
686         ierr = DMPlexSetCone(sdm, splitp, &coneNew[2]);CHKERRQ(ierr);
687         ierr = DMPlexSetConeOrientation(sdm, splitp, ornt);CHKERRQ(ierr);
688         /* Cohesive cell:    Old and new split face, then new cohesive edges */
689         coneNew[0] = newp;   coneONew[0] = -coneSize; /* We know it has to be negative to be on the negative side */
690         coneNew[1] = splitp; coneONew[1] = coneONew[0];
691         for (q = 0; q < coneSize; ++q) {
692           coneNew[2+q]  = (pMaxNew[1] - pMaxNew[dim-2]) + (depthShift[1] - depthShift[0]) + coneNew[2+q];
693           coneONew[2+q] = 0;
694         }
695         ierr = DMPlexSetCone(sdm, ccell, coneNew);CHKERRQ(ierr);
696         ierr = DMPlexSetConeOrientation(sdm, ccell, coneONew);CHKERRQ(ierr);
697 
698         for (s = 0; s < supportSize; ++s) {
699           PetscInt val;
700 
701           ierr = DMLabelGetValue(label, support[s], &val);CHKERRQ(ierr);
702           if (val < 0) {
703             /* Split old face:   Replace negative side cell with cohesive cell */
704             ierr = DMPlexInsertSupport(sdm, newp, s, ccell);CHKERRQ(ierr);
705           } else {
706             /* Split new face:   Replace positive side cell with cohesive cell */
707             ierr = DMPlexInsertSupport(sdm, splitp, s, ccell);CHKERRQ(ierr);
708           }
709         }
710       } else if (dep == 0) {
711         const PetscInt cedge = pMaxNew[1] + (depthShift[1] - depthShift[0]) + p;
712 
713         /* Split old vertex: Edges in old split faces and new cohesive edge */
714         for (e = 0, q = 0; e < supportSize; ++e) {
715           PetscInt val;
716 
717           ierr = DMLabelGetValue(label, support[e], &val);CHKERRQ(ierr);
718           if ((val == 1) || (val == (shift + 1))) {
719             supportNew[q++] = depthOffset[1] + support[e];
720           }
721         }
722         supportNew[q] = cedge;
723 
724         ierr = DMPlexSetSupport(sdm, newp, supportNew);CHKERRQ(ierr);
725         /* Split new vertex: Edges in new split faces and new cohesive edge */
726         for (e = 0, q = 0; e < supportSize; ++e) {
727           PetscInt val, edge;
728 
729           ierr = DMLabelGetValue(label, support[e], &val);CHKERRQ(ierr);
730           if (val == 1) {
731             ierr = PetscFindInt(support[e], numSplitPoints[1], splitPoints[1], &edge);CHKERRQ(ierr);
732             if (edge < 0) SETERRQ1(comm, PETSC_ERR_ARG_WRONG, "Edge %d is not a split edge", support[e]);
733             supportNew[q++] = pMaxNew[1] + edge;
734           } else if (val == -(shift + 1)) {
735             supportNew[q++] = depthOffset[1] + support[e];
736           }
737         }
738         supportNew[q] = cedge;
739         ierr          = DMPlexSetSupport(sdm, splitp, supportNew);CHKERRQ(ierr);
740         /* Cohesive edge:    Old and new split vertex, punting on support */
741         coneNew[0] = newp;
742         coneNew[1] = splitp;
743         ierr       = DMPlexSetCone(sdm, cedge, coneNew);CHKERRQ(ierr);
744       } else if (dep == dim-2) {
745         /* Split old edge:   old vertices in cone so no change */
746         /* Split new edge:   new vertices in cone */
747         for (q = 0; q < coneSize; ++q) {
748           ierr = PetscFindInt(cone[q], numSplitPoints[dim-3], splitPoints[dim-3], &v);CHKERRQ(ierr);
749 
750           coneNew[q] = pMaxNew[dim-3] + v;
751         }
752         ierr = DMPlexSetCone(sdm, splitp, coneNew);CHKERRQ(ierr);
753         /* Split old edge: Faces in positive side cells and old split faces */
754         for (e = 0, q = 0; e < supportSize; ++e) {
755           PetscInt val;
756 
757           ierr = DMLabelGetValue(label, support[e], &val);CHKERRQ(ierr);
758           if ((val == dim-1) || (val == (shift + dim-1))) {
759             supportNew[q++] = depthOffset[dim-1] + support[e];
760           }
761         }
762         ierr = DMPlexSetSupport(sdm, newp, supportNew);CHKERRQ(ierr);
763         /* Split new edge: Faces in negative side cells and new split faces */
764         for (e = 0, q = 0; e < supportSize; ++e) {
765           PetscInt val, face;
766 
767           ierr = DMLabelGetValue(label, support[e], &val);CHKERRQ(ierr);
768           if (val == dim-1) {
769             ierr = PetscFindInt(support[e], numSplitPoints[dim-1], splitPoints[dim-1], &face);CHKERRQ(ierr);
770             if (face < 0) SETERRQ1(comm, PETSC_ERR_ARG_WRONG, "Face %d is not a split face", support[e]);
771             supportNew[q++] = pMaxNew[dim-1] + face;
772           } else if (val == -(shift + dim-1)) {
773             supportNew[q++] = depthOffset[dim-1] + support[e];
774           }
775         }
776         ierr = DMPlexSetSupport(sdm, splitp, supportNew);CHKERRQ(ierr);
777       }
778     }
779   }
780   /* Step 6b: Replace split points in negative side cones */
781   for (sp = 0; sp < numSP; ++sp) {
782     PetscInt        dep = values[sp];
783     IS              pIS;
784     PetscInt        numPoints;
785     const PetscInt *points;
786 
787     if (dep >= 0) continue;
788     ierr = DMLabelGetStratumIS(label, dep, &pIS);CHKERRQ(ierr);
789     if (!pIS) continue;
790     dep  = -dep - shift;
791     ierr = ISGetLocalSize(pIS, &numPoints);CHKERRQ(ierr);
792     ierr = ISGetIndices(pIS, &points);CHKERRQ(ierr);
793     for (p = 0; p < numPoints; ++p) {
794       const PetscInt  oldp = points[p];
795       const PetscInt  newp = depthOffset[dep] + oldp;
796       const PetscInt *cone;
797       PetscInt        coneSize, c;
798       PetscBool       replaced = PETSC_FALSE;
799 
800       /* Negative edge: replace split vertex */
801       /* Negative cell: replace split face */
802       ierr = DMPlexGetConeSize(sdm, newp, &coneSize);CHKERRQ(ierr);
803       ierr = DMPlexGetCone(sdm, newp, &cone);CHKERRQ(ierr);
804       for (c = 0; c < coneSize; ++c) {
805         const PetscInt coldp = cone[c] - depthOffset[dep-1];
806         PetscInt       csplitp, cp, val;
807 
808         ierr = DMLabelGetValue(label, coldp, &val);CHKERRQ(ierr);
809         if (val == dep-1) {
810           ierr = PetscFindInt(coldp, numSplitPoints[dep-1], splitPoints[dep-1], &cp);CHKERRQ(ierr);
811           if (cp < 0) SETERRQ2(comm, PETSC_ERR_ARG_WRONG, "Point %d is not a split point of dimension %d", oldp, dep-1);
812           csplitp  = pMaxNew[dep-1] + cp;
813           ierr     = DMPlexInsertCone(sdm, newp, c, csplitp);CHKERRQ(ierr);
814           replaced = PETSC_TRUE;
815         }
816       }
817       if (!replaced) SETERRQ1(comm, PETSC_ERR_ARG_WRONG, "The cone of point %d does not contain split points", oldp);
818     }
819     ierr = ISRestoreIndices(pIS, &points);CHKERRQ(ierr);
820     ierr = ISDestroy(&pIS);CHKERRQ(ierr);
821   }
822   /* Step 7: Stratify */
823   ierr = DMPlexStratify(sdm);CHKERRQ(ierr);
824   /* Step 8: Coordinates */
825   ierr = DMPlexShiftCoordinates_Internal(dm, depthShift, sdm);CHKERRQ(ierr);
826   ierr = DMPlexGetCoordinateSection(sdm, &coordSection);CHKERRQ(ierr);
827   ierr = DMGetCoordinatesLocal(sdm, &coordinates);CHKERRQ(ierr);
828   ierr = VecGetArray(coordinates, &coords);CHKERRQ(ierr);
829   for (v = 0; v < (numSplitPoints ? numSplitPoints[0] : 0); ++v) {
830     const PetscInt newp   = depthOffset[0] + splitPoints[0][v];
831     const PetscInt splitp = pMaxNew[0] + v;
832     PetscInt       dof, off, soff, d;
833 
834     ierr = PetscSectionGetDof(coordSection, newp, &dof);CHKERRQ(ierr);
835     ierr = PetscSectionGetOffset(coordSection, newp, &off);CHKERRQ(ierr);
836     ierr = PetscSectionGetOffset(coordSection, splitp, &soff);CHKERRQ(ierr);
837     for (d = 0; d < dof; ++d) coords[soff+d] = coords[off+d];
838   }
839   ierr = VecRestoreArray(coordinates, &coords);CHKERRQ(ierr);
840   /* Step 9: SF, if I can figure this out we can split the mesh in parallel */
841   ierr = DMPlexShiftSF_Internal(dm, depthShift, sdm);CHKERRQ(ierr);
842   /* Step 10: Labels */
843   ierr = DMPlexShiftLabels_Internal(dm, depthShift, sdm);CHKERRQ(ierr);
844   ierr = DMPlexGetNumLabels(sdm, &numLabels);CHKERRQ(ierr);
845   for (dep = 0; dep <= depth; ++dep) {
846     for (p = 0; p < numSplitPoints[dep]; ++p) {
847       const PetscInt newp   = depthOffset[dep] + splitPoints[dep][p];
848       const PetscInt splitp = pMaxNew[dep] + p;
849       PetscInt       l;
850 
851       for (l = 0; l < numLabels; ++l) {
852         DMLabel     mlabel;
853         const char *lname;
854         PetscInt    val;
855 
856         ierr = DMPlexGetLabelName(sdm, l, &lname);CHKERRQ(ierr);
857         ierr = DMPlexGetLabel(sdm, lname, &mlabel);CHKERRQ(ierr);
858         ierr = DMLabelGetValue(mlabel, newp, &val);CHKERRQ(ierr);
859         if (val >= 0) {
860           ierr = DMLabelSetValue(mlabel, splitp, val);CHKERRQ(ierr);
861           if (dep == 0) {
862             const PetscInt cedge = pMaxNew[1] + (depthShift[1] - depthShift[0]) + p;
863             ierr = DMLabelSetValue(mlabel, cedge, val);CHKERRQ(ierr);
864           }
865         }
866       }
867     }
868   }
869   for (sp = 0; sp < numSP; ++sp) {
870     const PetscInt dep = values[sp];
871 
872     if ((dep < 0) || (dep > depth)) continue;
873     if (pointIS[dep]) {ierr = ISRestoreIndices(pointIS[dep], &splitPoints[dep]);CHKERRQ(ierr);}
874     ierr = ISDestroy(&pointIS[dep]);CHKERRQ(ierr);
875   }
876   if (label) {
877     ierr = ISRestoreIndices(valueIS, &values);CHKERRQ(ierr);
878     ierr = ISDestroy(&valueIS);CHKERRQ(ierr);
879   }
880   ierr = DMPlexGetChart(sdm, NULL, &pEnd);CHKERRQ(ierr);
881   if (depth > 0) pMaxNew[0] += depthShift[0];        /* Account for shadow vertices */
882   if (depth > 1) pMaxNew[1]  = pEnd - depthShift[0]; /* There is a hybrid edge for every shadow vertex */
883   if (depth > 2) pMaxNew[2]  = -1;                   /* There are no hybrid faces */
884   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);
885   ierr = PetscFree6(depthShift, depthOffset, pMaxNew, coneNew, coneONew, supportNew);CHKERRQ(ierr);
886   ierr = PetscFree3(pointIS, numSplitPoints, splitPoints);CHKERRQ(ierr);
887   PetscFunctionReturn(0);
888 }
889 
890 #undef __FUNCT__
891 #define __FUNCT__ "DMPlexConstructCohesiveCells"
892 /*@C
893   DMPlexConstructCohesiveCells - Construct cohesive cells which split the face along an internal interface
894 
895   Collective on dm
896 
897   Input Parameters:
898 + dm - The original DM
899 - labelName - The label specifying the boundary faces (this could be auto-generated)
900 
901   Output Parameters:
902 - dmSplit - The new DM
903 
904   Level: developer
905 
906 .seealso: DMCreate(), DMPlexLabelCohesiveComplete()
907 @*/
908 PetscErrorCode DMPlexConstructCohesiveCells(DM dm, DMLabel label, DM *dmSplit)
909 {
910   DM             sdm;
911   PetscInt       dim;
912   PetscErrorCode ierr;
913 
914   PetscFunctionBegin;
915   PetscValidHeaderSpecific(dm, DM_CLASSID, 1);
916   PetscValidPointer(dmSplit, 4);
917   ierr = DMCreate(PetscObjectComm((PetscObject)dm), &sdm);CHKERRQ(ierr);
918   ierr = DMSetType(sdm, DMPLEX);CHKERRQ(ierr);
919   ierr = DMPlexGetDimension(dm, &dim);CHKERRQ(ierr);
920   ierr = DMPlexSetDimension(sdm, dim);CHKERRQ(ierr);
921   switch (dim) {
922   case 2:
923   case 3:
924     ierr = DMPlexConstructCohesiveCells_Internal(dm, label, sdm);CHKERRQ(ierr);
925     break;
926   default:
927     SETERRQ1(PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_OUTOFRANGE, "Cannot construct cohesive cells for dimension %d", dim);
928   }
929   *dmSplit = sdm;
930   PetscFunctionReturn(0);
931 }
932 
933 #undef __FUNCT__
934 #define __FUNCT__ "DMPlexLabelCohesiveComplete"
935 /*@
936   DMPlexLabelCohesiveComplete - Starting with a label marking vertices on an internal surface, we add all other mesh pieces
937   to complete the surface
938 
939   Input Parameters:
940 + dm - The DM
941 . label - A DMLabel marking the surface vertices
942 - subdm - The subDM associated with the label, or NULL
943 
944   Output Parameter:
945 . label - A DMLabel marking all surface points
946 
947   Level: developer
948 
949 .seealso: DMPlexConstructCohesiveCells(), DMPlexLabelComplete()
950 @*/
951 PetscErrorCode DMPlexLabelCohesiveComplete(DM dm, DMLabel label, DM subdm)
952 {
953   IS              dimIS, subpointIS;
954   const PetscInt *points, *subpoints;
955   PetscInt        shift = 100, dim, dep, cStart, cEnd, numPoints, numSubpoints, p, val;
956   PetscErrorCode  ierr;
957 
958   PetscFunctionBegin;
959   ierr = DMPlexGetDimension(dm, &dim);CHKERRQ(ierr);
960   if (subdm) {
961     ierr = DMPlexCreateSubpointIS(subdm, &subpointIS);CHKERRQ(ierr);
962     if (subpointIS) {
963       ierr = ISGetLocalSize(subpointIS, &numSubpoints);CHKERRQ(ierr);
964       ierr = ISGetIndices(subpointIS, &subpoints);CHKERRQ(ierr);
965     }
966   }
967   /* Cell orientation for face gives the side of the fault */
968   ierr = DMLabelGetStratumIS(label, dim-1, &dimIS);CHKERRQ(ierr);
969   if (!dimIS) PetscFunctionReturn(0);
970   ierr = ISGetLocalSize(dimIS, &numPoints);CHKERRQ(ierr);
971   ierr = ISGetIndices(dimIS, &points);CHKERRQ(ierr);
972   for (p = 0; p < numPoints; ++p) {
973     const PetscInt *support;
974     PetscInt        supportSize, s;
975 
976     ierr = DMPlexGetSupportSize(dm, points[p], &supportSize);CHKERRQ(ierr);
977     if (supportSize != 2) SETERRQ2(PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_WRONG, "Split face %d has %d != 2 supports", points[p], supportSize);
978     ierr = DMPlexGetSupport(dm, points[p], &support);CHKERRQ(ierr);
979     for (s = 0; s < supportSize; ++s) {
980       const PetscInt *cone, *ornt;
981       PetscInt        coneSize, c;
982       PetscBool       pos = PETSC_TRUE;
983 
984       ierr = DMPlexGetConeSize(dm, support[s], &coneSize);CHKERRQ(ierr);
985       ierr = DMPlexGetCone(dm, support[s], &cone);CHKERRQ(ierr);
986       ierr = DMPlexGetConeOrientation(dm, support[s], &ornt);CHKERRQ(ierr);
987       for (c = 0; c < coneSize; ++c) {
988         if (cone[c] == points[p]) {
989           PetscInt o = ornt[c];
990 
991           if (subdm) {
992             const PetscInt *subcone, *subornt;
993             PetscInt        subpoint, subface, subconeSize, sc;
994 
995             ierr = PetscFindInt(support[s], numSubpoints, subpoints, &subpoint);CHKERRQ(ierr);
996             ierr = PetscFindInt(points[p],  numSubpoints, subpoints, &subface);CHKERRQ(ierr);
997             ierr = DMPlexGetConeSize(subdm, subpoint, &subconeSize);CHKERRQ(ierr);
998             ierr = DMPlexGetCone(subdm, subpoint, &subcone);CHKERRQ(ierr);
999             ierr = DMPlexGetConeOrientation(subdm, subpoint, &subornt);CHKERRQ(ierr);
1000             for (sc = 0; sc < subconeSize; ++sc) {
1001               if (subcone[sc] == subface) {
1002                 o = subornt[0];
1003                 break;
1004               }
1005             }
1006             if (sc >= subconeSize) SETERRQ2(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Could not find point %d in cone for subpoint %d", points[p], subpoint);
1007           }
1008 #if 1
1009           if (o >= 0) {
1010 #else
1011           if (o < 0) {
1012 #endif
1013             ierr = DMLabelSetValue(label, support[s],   shift+dim);CHKERRQ(ierr);
1014           } else {
1015             ierr = DMLabelSetValue(label, support[s], -(shift+dim));CHKERRQ(ierr);
1016             pos  = PETSC_FALSE;
1017           }
1018           break;
1019         }
1020       }
1021       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]);
1022       /* Put faces touching the fault in the label */
1023       for (c = 0; c < coneSize; ++c) {
1024         const PetscInt point = cone[c];
1025 
1026         ierr = DMLabelGetValue(label, point, &val);CHKERRQ(ierr);
1027         if (val == -1) {
1028           PetscInt *closure = NULL;
1029           PetscInt  closureSize, cl;
1030 
1031           ierr = DMPlexGetTransitiveClosure(dm, point, PETSC_TRUE, &closureSize, &closure);CHKERRQ(ierr);
1032           for (cl = 0; cl < closureSize*2; cl += 2) {
1033             const PetscInt clp = closure[cl];
1034 
1035             ierr = DMLabelGetValue(label, clp, &val);CHKERRQ(ierr);
1036             if ((val >= 0) && (val < dim-1)) {
1037               ierr = DMLabelSetValue(label, point, pos == PETSC_TRUE ? shift+dim-1 : -(shift+dim-1));CHKERRQ(ierr);
1038               break;
1039             }
1040           }
1041           ierr = DMPlexRestoreTransitiveClosure(dm, point, PETSC_TRUE, &closureSize, &closure);CHKERRQ(ierr);
1042         }
1043       }
1044     }
1045   }
1046   if (subdm) {
1047     if (subpointIS) {ierr = ISRestoreIndices(subpointIS, &subpoints);CHKERRQ(ierr);}
1048     ierr = ISDestroy(&subpointIS);CHKERRQ(ierr);
1049   }
1050   ierr = ISRestoreIndices(dimIS, &points);CHKERRQ(ierr);
1051   ierr = ISDestroy(&dimIS);CHKERRQ(ierr);
1052   /* Search for other cells/faces/edges connected to the fault by a vertex */
1053   ierr = DMPlexGetHeightStratum(dm, 0, &cStart, &cEnd);CHKERRQ(ierr);
1054   ierr = DMLabelGetStratumIS(label, 0, &dimIS);CHKERRQ(ierr);
1055   if (!dimIS) PetscFunctionReturn(0);
1056   ierr = ISGetLocalSize(dimIS, &numPoints);CHKERRQ(ierr);
1057   ierr = ISGetIndices(dimIS, &points);CHKERRQ(ierr);
1058   for (p = 0; p < numPoints; ++p) {
1059     PetscInt *star = NULL;
1060     PetscInt  starSize, s;
1061     PetscInt  again = 1;  /* 0: Finished 1: Keep iterating after a change 2: No change */
1062 
1063     /* First mark cells connected to the fault */
1064     ierr = DMPlexGetTransitiveClosure(dm, points[p], PETSC_FALSE, &starSize, &star);CHKERRQ(ierr);
1065     while (again) {
1066       if (again > 1) SETERRQ(PetscObjectComm((PetscObject)dm), PETSC_ERR_PLIB, "Could not classify all cells connected to the fault");
1067       again = 0;
1068       for (s = 0; s < starSize*2; s += 2) {
1069         const PetscInt  point = star[s];
1070         const PetscInt *cone;
1071         PetscInt        coneSize, c;
1072 
1073         if ((point < cStart) || (point >= cEnd)) continue;
1074         ierr = DMLabelGetValue(label, point, &val);CHKERRQ(ierr);
1075         if (val != -1) continue;
1076         again = 2;
1077         ierr  = DMPlexGetConeSize(dm, point, &coneSize);CHKERRQ(ierr);
1078         ierr  = DMPlexGetCone(dm, point, &cone);CHKERRQ(ierr);
1079         for (c = 0; c < coneSize; ++c) {
1080           ierr = DMLabelGetValue(label, cone[c], &val);CHKERRQ(ierr);
1081           if (val != -1) {
1082             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);
1083             if (val > 0) {
1084               ierr = DMLabelSetValue(label, point,   shift+dim);CHKERRQ(ierr);
1085             } else {
1086               ierr = DMLabelSetValue(label, point, -(shift+dim));CHKERRQ(ierr);
1087             }
1088             again = 1;
1089             break;
1090           }
1091         }
1092       }
1093     }
1094     /* Classify the rest by cell membership */
1095     for (s = 0; s < starSize*2; s += 2) {
1096       const PetscInt point = star[s];
1097 
1098       ierr = DMLabelGetValue(label, point, &val);CHKERRQ(ierr);
1099       if (val == -1) {
1100         PetscInt  *sstar = NULL;
1101         PetscInt   sstarSize, ss;
1102         PetscBool  marked = PETSC_FALSE;
1103 
1104         ierr = DMPlexGetTransitiveClosure(dm, point, PETSC_FALSE, &sstarSize, &sstar);CHKERRQ(ierr);
1105         for (ss = 0; ss < sstarSize*2; ss += 2) {
1106           const PetscInt spoint = sstar[ss];
1107 
1108           if ((spoint < cStart) || (spoint >= cEnd)) continue;
1109           ierr = DMLabelGetValue(label, spoint, &val);CHKERRQ(ierr);
1110           if (val == -1) SETERRQ2(PetscObjectComm((PetscObject)dm), PETSC_ERR_PLIB, "Cell %d in star of %d does not have a valid label", spoint, point);
1111           ierr = DMPlexGetLabelValue(dm, "depth", point, &dep);CHKERRQ(ierr);
1112           if (val > 0) {
1113             ierr = DMLabelSetValue(label, point,   shift+dep);CHKERRQ(ierr);
1114           } else {
1115             ierr = DMLabelSetValue(label, point, -(shift+dep));CHKERRQ(ierr);
1116           }
1117           marked = PETSC_TRUE;
1118           break;
1119         }
1120         ierr = DMPlexRestoreTransitiveClosure(dm, point, PETSC_FALSE, &sstarSize, &sstar);CHKERRQ(ierr);
1121         if (!marked) SETERRQ1(PetscObjectComm((PetscObject)dm), PETSC_ERR_PLIB, "Point %d could not be classified", point);
1122       }
1123     }
1124     ierr = DMPlexRestoreTransitiveClosure(dm, points[p], PETSC_FALSE, &starSize, &star);CHKERRQ(ierr);
1125   }
1126   ierr = ISRestoreIndices(dimIS, &points);CHKERRQ(ierr);
1127   ierr = ISDestroy(&dimIS);CHKERRQ(ierr);
1128   PetscFunctionReturn(0);
1129 }
1130 
1131 #undef __FUNCT__
1132 #define __FUNCT__ "DMPlexMarkSubmesh_Uninterpolated"
1133 /* Here we need the explicit assumption that:
1134 
1135      For any marked cell, the marked vertices constitute a single face
1136 */
1137 static PetscErrorCode DMPlexMarkSubmesh_Uninterpolated(DM dm, DMLabel vertexLabel, PetscInt value, DMLabel subpointMap, PetscInt *numFaces, PetscInt *nFV, DM subdm)
1138 {
1139   IS               subvertexIS;
1140   const PetscInt  *subvertices;
1141   PetscInt        *pStart, *pEnd, *pMax, pSize;
1142   PetscInt         depth, dim, d, numSubVerticesInitial = 0, v;
1143   PetscErrorCode   ierr;
1144 
1145   PetscFunctionBegin;
1146   *numFaces = 0;
1147   *nFV      = 0;
1148   ierr = DMPlexGetDepth(dm, &depth);CHKERRQ(ierr);
1149   ierr = DMPlexGetDimension(dm, &dim);CHKERRQ(ierr);
1150   pSize = PetscMax(depth, dim) + 1;
1151   ierr = PetscMalloc3(pSize,PetscInt,&pStart,pSize,PetscInt,&pEnd,pSize,PetscInt,&pMax);CHKERRQ(ierr);
1152   ierr = DMPlexGetHybridBounds(dm, &pMax[depth], depth>1 ? &pMax[depth-1] : NULL, depth > 2 ? &pMax[1] : NULL, &pMax[0]);CHKERRQ(ierr);
1153   for (d = 0; d <= depth; ++d) {
1154     ierr = DMPlexGetDepthStratum(dm, d, &pStart[d], &pEnd[d]);CHKERRQ(ierr);
1155     if (pMax[d] >= 0) pEnd[d] = PetscMin(pEnd[d], pMax[d]);
1156   }
1157   /* Loop over initial vertices and mark all faces in the collective star() */
1158   ierr = DMLabelGetStratumIS(vertexLabel, value, &subvertexIS);CHKERRQ(ierr);
1159   if (subvertexIS) {
1160     ierr = ISGetSize(subvertexIS, &numSubVerticesInitial);CHKERRQ(ierr);
1161     ierr = ISGetIndices(subvertexIS, &subvertices);CHKERRQ(ierr);
1162   }
1163   for (v = 0; v < numSubVerticesInitial; ++v) {
1164     const PetscInt vertex = subvertices[v];
1165     PetscInt      *star   = NULL;
1166     PetscInt       starSize, s, numCells = 0, c;
1167 
1168     ierr = DMPlexGetTransitiveClosure(dm, vertex, PETSC_FALSE, &starSize, &star);CHKERRQ(ierr);
1169     for (s = 0; s < starSize*2; s += 2) {
1170       const PetscInt point = star[s];
1171       if ((point >= pStart[depth]) && (point < pEnd[depth])) star[numCells++] = point;
1172     }
1173     for (c = 0; c < numCells; ++c) {
1174       const PetscInt cell    = star[c];
1175       PetscInt      *closure = NULL;
1176       PetscInt       closureSize, cl;
1177       PetscInt       cellLoc, numCorners = 0, faceSize = 0;
1178 
1179       ierr = DMLabelGetValue(subpointMap, cell, &cellLoc);CHKERRQ(ierr);
1180       if (cellLoc == 2) continue;
1181       if (cellLoc >= 0) SETERRQ2(PetscObjectComm((PetscObject)dm), PETSC_ERR_PLIB, "Cell %d has dimension %d in the surface label", cell, cellLoc);
1182       ierr = DMPlexGetTransitiveClosure(dm, cell, PETSC_TRUE, &closureSize, &closure);CHKERRQ(ierr);
1183       for (cl = 0; cl < closureSize*2; cl += 2) {
1184         const PetscInt point = closure[cl];
1185         PetscInt       vertexLoc;
1186 
1187         if ((point >= pStart[0]) && (point < pEnd[0])) {
1188           ++numCorners;
1189           ierr = DMLabelGetValue(vertexLabel, point, &vertexLoc);CHKERRQ(ierr);
1190           if (vertexLoc == value) closure[faceSize++] = point;
1191         }
1192       }
1193       if (!(*nFV)) {ierr = DMPlexGetNumFaceVertices(dm, dim, numCorners, nFV);CHKERRQ(ierr);}
1194       if (faceSize > *nFV) SETERRQ1(PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_WRONG, "Invalid submesh: Too many vertices %d of an element on the surface", faceSize);
1195       if (faceSize == *nFV) {
1196         const PetscInt *cells = NULL;
1197         PetscInt        numCells, nc;
1198 
1199         ++(*numFaces);
1200         for (cl = 0; cl < faceSize; ++cl) {
1201           ierr = DMLabelSetValue(subpointMap, closure[cl], 0);CHKERRQ(ierr);
1202         }
1203         ierr = DMPlexGetJoin(dm, faceSize, closure, &numCells, &cells);CHKERRQ(ierr);
1204         for (nc = 0; nc < numCells; ++nc) {
1205           ierr = DMLabelSetValue(subpointMap, cells[nc], 2);CHKERRQ(ierr);
1206         }
1207         ierr = DMPlexRestoreJoin(dm, faceSize, closure, &numCells, &cells);CHKERRQ(ierr);
1208       }
1209       ierr = DMPlexRestoreTransitiveClosure(dm, cell, PETSC_TRUE, &closureSize, &closure);CHKERRQ(ierr);
1210     }
1211     ierr = DMPlexRestoreTransitiveClosure(dm, vertex, PETSC_FALSE, &starSize, &star);CHKERRQ(ierr);
1212   }
1213   if (subvertexIS) {
1214     ierr = ISRestoreIndices(subvertexIS, &subvertices);CHKERRQ(ierr);
1215   }
1216   ierr = ISDestroy(&subvertexIS);CHKERRQ(ierr);
1217   ierr = PetscFree3(pStart,pEnd,pMax);CHKERRQ(ierr);
1218   PetscFunctionReturn(0);
1219 }
1220 
1221 #undef __FUNCT__
1222 #define __FUNCT__ "DMPlexMarkSubmesh_Interpolated"
1223 static PetscErrorCode DMPlexMarkSubmesh_Interpolated(DM dm, DMLabel vertexLabel, PetscInt value, DMLabel subpointMap, DM subdm)
1224 {
1225   IS               subvertexIS;
1226   const PetscInt  *subvertices;
1227   PetscInt        *pStart, *pEnd, *pMax;
1228   PetscInt         dim, d, numSubVerticesInitial = 0, v;
1229   PetscErrorCode   ierr;
1230 
1231   PetscFunctionBegin;
1232   ierr = DMPlexGetDimension(dm, &dim);CHKERRQ(ierr);
1233   ierr = PetscMalloc3(dim+1,PetscInt,&pStart,dim+1,PetscInt,&pEnd,dim+1,PetscInt,&pMax);CHKERRQ(ierr);
1234   ierr = DMPlexGetHybridBounds(dm, &pMax[dim], dim>1 ? &pMax[dim-1] : NULL, dim > 2 ? &pMax[1] : NULL, &pMax[0]);CHKERRQ(ierr);
1235   for (d = 0; d <= dim; ++d) {
1236     ierr = DMPlexGetDepthStratum(dm, d, &pStart[d], &pEnd[d]);CHKERRQ(ierr);
1237     if (pMax[d] >= 0) pEnd[d] = PetscMin(pEnd[d], pMax[d]);
1238   }
1239   /* Loop over initial vertices and mark all faces in the collective star() */
1240   ierr = DMLabelGetStratumIS(vertexLabel, value, &subvertexIS);CHKERRQ(ierr);
1241   if (subvertexIS) {
1242     ierr = ISGetSize(subvertexIS, &numSubVerticesInitial);CHKERRQ(ierr);
1243     ierr = ISGetIndices(subvertexIS, &subvertices);CHKERRQ(ierr);
1244   }
1245   for (v = 0; v < numSubVerticesInitial; ++v) {
1246     const PetscInt vertex = subvertices[v];
1247     PetscInt      *star   = NULL;
1248     PetscInt       starSize, s, numFaces = 0, f;
1249 
1250     ierr = DMPlexGetTransitiveClosure(dm, vertex, PETSC_FALSE, &starSize, &star);CHKERRQ(ierr);
1251     for (s = 0; s < starSize*2; s += 2) {
1252       const PetscInt point = star[s];
1253       if ((point >= pStart[dim-1]) && (point < pEnd[dim-1])) star[numFaces++] = point;
1254     }
1255     for (f = 0; f < numFaces; ++f) {
1256       const PetscInt face    = star[f];
1257       PetscInt      *closure = NULL;
1258       PetscInt       closureSize, c;
1259       PetscInt       faceLoc;
1260 
1261       ierr = DMLabelGetValue(subpointMap, face, &faceLoc);CHKERRQ(ierr);
1262       if (faceLoc == dim-1) continue;
1263       if (faceLoc >= 0) SETERRQ2(PetscObjectComm((PetscObject)dm), PETSC_ERR_PLIB, "Face %d has dimension %d in the surface label", face, faceLoc);
1264       ierr = DMPlexGetTransitiveClosure(dm, face, PETSC_TRUE, &closureSize, &closure);CHKERRQ(ierr);
1265       for (c = 0; c < closureSize*2; c += 2) {
1266         const PetscInt point = closure[c];
1267         PetscInt       vertexLoc;
1268 
1269         if ((point >= pStart[0]) && (point < pEnd[0])) {
1270           ierr = DMLabelGetValue(vertexLabel, point, &vertexLoc);CHKERRQ(ierr);
1271           if (vertexLoc != value) break;
1272         }
1273       }
1274       if (c == closureSize*2) {
1275         const PetscInt *support;
1276         PetscInt        supportSize, s;
1277 
1278         for (c = 0; c < closureSize*2; c += 2) {
1279           const PetscInt point = closure[c];
1280 
1281           for (d = 0; d < dim; ++d) {
1282             if ((point >= pStart[d]) && (point < pEnd[d])) {
1283               ierr = DMLabelSetValue(subpointMap, point, d);CHKERRQ(ierr);
1284               break;
1285             }
1286           }
1287         }
1288         ierr = DMPlexGetSupportSize(dm, face, &supportSize);CHKERRQ(ierr);
1289         ierr = DMPlexGetSupport(dm, face, &support);CHKERRQ(ierr);
1290         for (s = 0; s < supportSize; ++s) {
1291           ierr = DMLabelSetValue(subpointMap, support[s], dim);CHKERRQ(ierr);
1292         }
1293       }
1294       ierr = DMPlexRestoreTransitiveClosure(dm, face, PETSC_TRUE, &closureSize, &closure);CHKERRQ(ierr);
1295     }
1296     ierr = DMPlexRestoreTransitiveClosure(dm, vertex, PETSC_FALSE, &starSize, &star);CHKERRQ(ierr);
1297   }
1298   if (subvertexIS) {
1299     ierr = ISRestoreIndices(subvertexIS, &subvertices);CHKERRQ(ierr);
1300   }
1301   ierr = ISDestroy(&subvertexIS);CHKERRQ(ierr);
1302   ierr = PetscFree3(pStart,pEnd,pMax);CHKERRQ(ierr);
1303   PetscFunctionReturn(0);
1304 }
1305 
1306 #undef __FUNCT__
1307 #define __FUNCT__ "DMPlexMarkCohesiveSubmesh_Uninterpolated"
1308 static PetscErrorCode DMPlexMarkCohesiveSubmesh_Uninterpolated(DM dm, PetscBool hasLagrange, DMLabel subpointMap, PetscInt *numFaces, PetscInt *nFV, PetscInt *subCells[], DM subdm)
1309 {
1310   const PetscInt *cone;
1311   PetscInt        dim, cMax, cEnd, c, p, coneSize;
1312   PetscErrorCode  ierr;
1313 
1314   PetscFunctionBegin;
1315   *numFaces = 0;
1316   *nFV = 0;
1317   ierr = DMPlexGetDimension(dm, &dim);CHKERRQ(ierr);
1318   ierr = DMPlexGetHeightStratum(dm, 0, NULL, &cEnd);CHKERRQ(ierr);
1319   ierr = DMPlexGetHybridBounds(dm, &cMax, NULL, NULL, NULL);CHKERRQ(ierr);
1320   if (cMax < 0) PetscFunctionReturn(0);
1321   ierr = DMPlexGetConeSize(dm, cMax, &coneSize);CHKERRQ(ierr);
1322   *numFaces = cEnd - cMax;
1323   *nFV      = hasLagrange ? coneSize/3 : coneSize/2;
1324   ierr = PetscMalloc(*numFaces *2 * sizeof(PetscInt), subCells);CHKERRQ(ierr);
1325   for (c = cMax; c < cEnd; ++c) {
1326     const PetscInt *cells;
1327     PetscInt        numCells;
1328 
1329     ierr = DMPlexGetCone(dm, c, &cone);CHKERRQ(ierr);
1330     for (p = 0; p < *nFV; ++p) {
1331       ierr = DMLabelSetValue(subpointMap, cone[p], 0);CHKERRQ(ierr);
1332     }
1333     /* Negative face */
1334     ierr = DMPlexGetJoin(dm, *nFV, cone, &numCells, &cells);CHKERRQ(ierr);
1335     if (numCells != 2) SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Cohesive cells should separate two cells");
1336     for (p = 0; p < numCells; ++p) {
1337       ierr = DMLabelSetValue(subpointMap, cells[p], 2);CHKERRQ(ierr);
1338       (*subCells)[(c-cMax)*2+p] = cells[p];
1339     }
1340     ierr = DMPlexRestoreJoin(dm, *nFV, cone, &numCells, &cells);CHKERRQ(ierr);
1341     /* Positive face is not included */
1342   }
1343   PetscFunctionReturn(0);
1344 }
1345 
1346 #undef __FUNCT__
1347 #define __FUNCT__ "DMPlexMarkCohesiveSubmesh_Interpolated"
1348 static PetscErrorCode DMPlexMarkCohesiveSubmesh_Interpolated(DM dm, PetscBool hasLagrange, DMLabel subpointMap, DM subdm)
1349 {
1350   PetscInt      *pStart, *pEnd;
1351   PetscInt       dim, cMax, cEnd, c, d;
1352   PetscErrorCode ierr;
1353 
1354   PetscFunctionBegin;
1355   ierr = DMPlexGetDimension(dm, &dim);CHKERRQ(ierr);
1356   ierr = DMPlexGetHeightStratum(dm, 0, NULL, &cEnd);CHKERRQ(ierr);
1357   ierr = DMPlexGetHybridBounds(dm, &cMax, NULL, NULL, NULL);CHKERRQ(ierr);
1358   if (cMax < 0) PetscFunctionReturn(0);
1359   ierr = PetscMalloc2(dim+1,PetscInt,&pStart,dim+1,PetscInt,&pEnd);CHKERRQ(ierr);
1360   for (d = 0; d <= dim; ++d) {
1361     ierr = DMPlexGetDepthStratum(dm, d, &pStart[d], &pEnd[d]);CHKERRQ(ierr);
1362   }
1363   for (c = cMax; c < cEnd; ++c) {
1364     const PetscInt *cone;
1365     PetscInt       *closure = NULL;
1366     PetscInt        coneSize, closureSize, cl;
1367 
1368     ierr = DMPlexGetConeSize(dm, c, &coneSize);CHKERRQ(ierr);
1369     if (hasLagrange) {
1370       if (coneSize != 3) SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Cohesive cells should separate two cells");
1371     } else {
1372       if (coneSize != 2) SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Cohesive cells should separate two cells");
1373     }
1374     /* Negative face */
1375     ierr = DMPlexGetCone(dm, c, &cone);CHKERRQ(ierr);
1376     ierr = DMPlexGetTransitiveClosure(dm, cone[0], PETSC_TRUE, &closureSize, &closure);CHKERRQ(ierr);
1377     for (cl = 0; cl < closureSize*2; cl += 2) {
1378       const PetscInt point = closure[cl];
1379 
1380       for (d = 0; d <= dim; ++d) {
1381         if ((point >= pStart[d]) && (point < pEnd[d])) {
1382           ierr = DMLabelSetValue(subpointMap, point, d);CHKERRQ(ierr);
1383           break;
1384         }
1385       }
1386     }
1387     ierr = DMPlexRestoreTransitiveClosure(dm, cone[0], PETSC_TRUE, &closureSize, &closure);CHKERRQ(ierr);
1388     /* Cells -- positive face is not included */
1389     for (cl = 0; cl < 1; ++cl) {
1390       const PetscInt *support;
1391       PetscInt        supportSize, s;
1392 
1393       ierr = DMPlexGetSupportSize(dm, cone[cl], &supportSize);CHKERRQ(ierr);
1394       if (supportSize != 2) SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Cohesive faces should separate two cells");
1395       ierr = DMPlexGetSupport(dm, cone[cl], &support);CHKERRQ(ierr);
1396       for (s = 0; s < supportSize; ++s) {
1397         ierr = DMLabelSetValue(subpointMap, support[s], dim);CHKERRQ(ierr);
1398       }
1399     }
1400   }
1401   ierr = PetscFree2(pStart, pEnd);CHKERRQ(ierr);
1402   PetscFunctionReturn(0);
1403 }
1404 
1405 #undef __FUNCT__
1406 #define __FUNCT__ "DMPlexGetFaceOrientation"
1407 PetscErrorCode DMPlexGetFaceOrientation(DM dm, PetscInt cell, PetscInt numCorners, PetscInt indices[], PetscInt oppositeVertex, PetscInt origVertices[], PetscInt faceVertices[], PetscBool *posOriented)
1408 {
1409   MPI_Comm       comm;
1410   PetscBool      posOrient = PETSC_FALSE;
1411   const PetscInt debug     = 0;
1412   PetscInt       cellDim, faceSize, f;
1413   PetscErrorCode ierr;
1414 
1415   PetscFunctionBegin;
1416   ierr = PetscObjectGetComm((PetscObject)dm,&comm);CHKERRQ(ierr);
1417   ierr = DMPlexGetDimension(dm, &cellDim);CHKERRQ(ierr);
1418   if (debug) {PetscPrintf(comm, "cellDim: %d numCorners: %d\n", cellDim, numCorners);CHKERRQ(ierr);}
1419 
1420   if (cellDim == numCorners-1) {
1421     /* Simplices */
1422     faceSize  = numCorners-1;
1423     posOrient = !(oppositeVertex%2) ? PETSC_TRUE : PETSC_FALSE;
1424   } else if (cellDim == 1 && numCorners == 3) {
1425     /* Quadratic line */
1426     faceSize  = 1;
1427     posOrient = PETSC_TRUE;
1428   } else if (cellDim == 2 && numCorners == 4) {
1429     /* Quads */
1430     faceSize = 2;
1431     if ((indices[1] > indices[0]) && (indices[1] - indices[0] == 1)) {
1432       posOrient = PETSC_TRUE;
1433     } else if ((indices[0] == 3) && (indices[1] == 0)) {
1434       posOrient = PETSC_TRUE;
1435     } else {
1436       if (((indices[0] > indices[1]) && (indices[0] - indices[1] == 1)) || ((indices[0] == 0) && (indices[1] == 3))) {
1437         posOrient = PETSC_FALSE;
1438       } else SETERRQ(comm, PETSC_ERR_ARG_WRONG, "Invalid quad crossedge");
1439     }
1440   } else if (cellDim == 2 && numCorners == 6) {
1441     /* Quadratic triangle (I hate this) */
1442     /* Edges are determined by the first 2 vertices (corners of edges) */
1443     const PetscInt faceSizeTri = 3;
1444     PetscInt       sortedIndices[3], i, iFace;
1445     PetscBool      found                    = PETSC_FALSE;
1446     PetscInt       faceVerticesTriSorted[9] = {
1447       0, 3,  4, /* bottom */
1448       1, 4,  5, /* right */
1449       2, 3,  5, /* left */
1450     };
1451     PetscInt       faceVerticesTri[9] = {
1452       0, 3,  4, /* bottom */
1453       1, 4,  5, /* right */
1454       2, 5,  3, /* left */
1455     };
1456 
1457     faceSize = faceSizeTri;
1458     for (i = 0; i < faceSizeTri; ++i) sortedIndices[i] = indices[i];
1459     ierr = PetscSortInt(faceSizeTri, sortedIndices);CHKERRQ(ierr);
1460     for (iFace = 0; iFace < 3; ++iFace) {
1461       const PetscInt ii = iFace*faceSizeTri;
1462       PetscInt       fVertex, cVertex;
1463 
1464       if ((sortedIndices[0] == faceVerticesTriSorted[ii+0]) &&
1465           (sortedIndices[1] == faceVerticesTriSorted[ii+1])) {
1466         for (fVertex = 0; fVertex < faceSizeTri; ++fVertex) {
1467           for (cVertex = 0; cVertex < faceSizeTri; ++cVertex) {
1468             if (indices[cVertex] == faceVerticesTri[ii+fVertex]) {
1469               faceVertices[fVertex] = origVertices[cVertex];
1470               break;
1471             }
1472           }
1473         }
1474         found = PETSC_TRUE;
1475         break;
1476       }
1477     }
1478     if (!found) SETERRQ(comm, PETSC_ERR_ARG_WRONG, "Invalid tri crossface");
1479     if (posOriented) *posOriented = PETSC_TRUE;
1480     PetscFunctionReturn(0);
1481   } else if (cellDim == 2 && numCorners == 9) {
1482     /* Quadratic quad (I hate this) */
1483     /* Edges are determined by the first 2 vertices (corners of edges) */
1484     const PetscInt faceSizeQuad = 3;
1485     PetscInt       sortedIndices[3], i, iFace;
1486     PetscBool      found                      = PETSC_FALSE;
1487     PetscInt       faceVerticesQuadSorted[12] = {
1488       0, 1,  4, /* bottom */
1489       1, 2,  5, /* right */
1490       2, 3,  6, /* top */
1491       0, 3,  7, /* left */
1492     };
1493     PetscInt       faceVerticesQuad[12] = {
1494       0, 1,  4, /* bottom */
1495       1, 2,  5, /* right */
1496       2, 3,  6, /* top */
1497       3, 0,  7, /* left */
1498     };
1499 
1500     faceSize = faceSizeQuad;
1501     for (i = 0; i < faceSizeQuad; ++i) sortedIndices[i] = indices[i];
1502     ierr = PetscSortInt(faceSizeQuad, sortedIndices);CHKERRQ(ierr);
1503     for (iFace = 0; iFace < 4; ++iFace) {
1504       const PetscInt ii = iFace*faceSizeQuad;
1505       PetscInt       fVertex, cVertex;
1506 
1507       if ((sortedIndices[0] == faceVerticesQuadSorted[ii+0]) &&
1508           (sortedIndices[1] == faceVerticesQuadSorted[ii+1])) {
1509         for (fVertex = 0; fVertex < faceSizeQuad; ++fVertex) {
1510           for (cVertex = 0; cVertex < faceSizeQuad; ++cVertex) {
1511             if (indices[cVertex] == faceVerticesQuad[ii+fVertex]) {
1512               faceVertices[fVertex] = origVertices[cVertex];
1513               break;
1514             }
1515           }
1516         }
1517         found = PETSC_TRUE;
1518         break;
1519       }
1520     }
1521     if (!found) SETERRQ(comm, PETSC_ERR_ARG_WRONG, "Invalid quad crossface");
1522     if (posOriented) *posOriented = PETSC_TRUE;
1523     PetscFunctionReturn(0);
1524   } else if (cellDim == 3 && numCorners == 8) {
1525     /* Hexes
1526        A hex is two oriented quads with the normal of the first
1527        pointing up at the second.
1528 
1529           7---6
1530          /|  /|
1531         4---5 |
1532         | 3-|-2
1533         |/  |/
1534         0---1
1535 
1536         Faces are determined by the first 4 vertices (corners of faces) */
1537     const PetscInt faceSizeHex = 4;
1538     PetscInt       sortedIndices[4], i, iFace;
1539     PetscBool      found                     = PETSC_FALSE;
1540     PetscInt       faceVerticesHexSorted[24] = {
1541       0, 1, 2, 3,  /* bottom */
1542       4, 5, 6, 7,  /* top */
1543       0, 1, 4, 5,  /* front */
1544       1, 2, 5, 6,  /* right */
1545       2, 3, 6, 7,  /* back */
1546       0, 3, 4, 7,  /* left */
1547     };
1548     PetscInt       faceVerticesHex[24] = {
1549       3, 2, 1, 0,  /* bottom */
1550       4, 5, 6, 7,  /* top */
1551       0, 1, 5, 4,  /* front */
1552       1, 2, 6, 5,  /* right */
1553       2, 3, 7, 6,  /* back */
1554       3, 0, 4, 7,  /* left */
1555     };
1556 
1557     faceSize = faceSizeHex;
1558     for (i = 0; i < faceSizeHex; ++i) sortedIndices[i] = indices[i];
1559     ierr = PetscSortInt(faceSizeHex, sortedIndices);CHKERRQ(ierr);
1560     for (iFace = 0; iFace < 6; ++iFace) {
1561       const PetscInt ii = iFace*faceSizeHex;
1562       PetscInt       fVertex, cVertex;
1563 
1564       if ((sortedIndices[0] == faceVerticesHexSorted[ii+0]) &&
1565           (sortedIndices[1] == faceVerticesHexSorted[ii+1]) &&
1566           (sortedIndices[2] == faceVerticesHexSorted[ii+2]) &&
1567           (sortedIndices[3] == faceVerticesHexSorted[ii+3])) {
1568         for (fVertex = 0; fVertex < faceSizeHex; ++fVertex) {
1569           for (cVertex = 0; cVertex < faceSizeHex; ++cVertex) {
1570             if (indices[cVertex] == faceVerticesHex[ii+fVertex]) {
1571               faceVertices[fVertex] = origVertices[cVertex];
1572               break;
1573             }
1574           }
1575         }
1576         found = PETSC_TRUE;
1577         break;
1578       }
1579     }
1580     if (!found) SETERRQ(comm, PETSC_ERR_ARG_WRONG, "Invalid hex crossface");
1581     if (posOriented) *posOriented = PETSC_TRUE;
1582     PetscFunctionReturn(0);
1583   } else if (cellDim == 3 && numCorners == 10) {
1584     /* Quadratic tet */
1585     /* Faces are determined by the first 3 vertices (corners of faces) */
1586     const PetscInt faceSizeTet = 6;
1587     PetscInt       sortedIndices[6], i, iFace;
1588     PetscBool      found                     = PETSC_FALSE;
1589     PetscInt       faceVerticesTetSorted[24] = {
1590       0, 1, 2,  6, 7, 8, /* bottom */
1591       0, 3, 4,  6, 7, 9,  /* front */
1592       1, 4, 5,  7, 8, 9,  /* right */
1593       2, 3, 5,  6, 8, 9,  /* left */
1594     };
1595     PetscInt       faceVerticesTet[24] = {
1596       0, 1, 2,  6, 7, 8, /* bottom */
1597       0, 4, 3,  6, 7, 9,  /* front */
1598       1, 5, 4,  7, 8, 9,  /* right */
1599       2, 3, 5,  8, 6, 9,  /* left */
1600     };
1601 
1602     faceSize = faceSizeTet;
1603     for (i = 0; i < faceSizeTet; ++i) sortedIndices[i] = indices[i];
1604     ierr = PetscSortInt(faceSizeTet, sortedIndices);CHKERRQ(ierr);
1605     for (iFace=0; iFace < 4; ++iFace) {
1606       const PetscInt ii = iFace*faceSizeTet;
1607       PetscInt       fVertex, cVertex;
1608 
1609       if ((sortedIndices[0] == faceVerticesTetSorted[ii+0]) &&
1610           (sortedIndices[1] == faceVerticesTetSorted[ii+1]) &&
1611           (sortedIndices[2] == faceVerticesTetSorted[ii+2]) &&
1612           (sortedIndices[3] == faceVerticesTetSorted[ii+3])) {
1613         for (fVertex = 0; fVertex < faceSizeTet; ++fVertex) {
1614           for (cVertex = 0; cVertex < faceSizeTet; ++cVertex) {
1615             if (indices[cVertex] == faceVerticesTet[ii+fVertex]) {
1616               faceVertices[fVertex] = origVertices[cVertex];
1617               break;
1618             }
1619           }
1620         }
1621         found = PETSC_TRUE;
1622         break;
1623       }
1624     }
1625     if (!found) SETERRQ(comm, PETSC_ERR_ARG_WRONG, "Invalid tet crossface");
1626     if (posOriented) *posOriented = PETSC_TRUE;
1627     PetscFunctionReturn(0);
1628   } else if (cellDim == 3 && numCorners == 27) {
1629     /* Quadratic hexes (I hate this)
1630        A hex is two oriented quads with the normal of the first
1631        pointing up at the second.
1632 
1633          7---6
1634         /|  /|
1635        4---5 |
1636        | 3-|-2
1637        |/  |/
1638        0---1
1639 
1640        Faces are determined by the first 4 vertices (corners of faces) */
1641     const PetscInt faceSizeQuadHex = 9;
1642     PetscInt       sortedIndices[9], i, iFace;
1643     PetscBool      found                         = PETSC_FALSE;
1644     PetscInt       faceVerticesQuadHexSorted[54] = {
1645       0, 1, 2, 3,  8, 9, 10, 11,  24, /* bottom */
1646       4, 5, 6, 7,  12, 13, 14, 15,  25, /* top */
1647       0, 1, 4, 5,  8, 12, 16, 17,  22, /* front */
1648       1, 2, 5, 6,  9, 13, 17, 18,  21, /* right */
1649       2, 3, 6, 7,  10, 14, 18, 19,  23, /* back */
1650       0, 3, 4, 7,  11, 15, 16, 19,  20, /* left */
1651     };
1652     PetscInt       faceVerticesQuadHex[54] = {
1653       3, 2, 1, 0,  10, 9, 8, 11,  24, /* bottom */
1654       4, 5, 6, 7,  12, 13, 14, 15,  25, /* top */
1655       0, 1, 5, 4,  8, 17, 12, 16,  22, /* front */
1656       1, 2, 6, 5,  9, 18, 13, 17,  21, /* right */
1657       2, 3, 7, 6,  10, 19, 14, 18,  23, /* back */
1658       3, 0, 4, 7,  11, 16, 15, 19,  20 /* left */
1659     };
1660 
1661     faceSize = faceSizeQuadHex;
1662     for (i = 0; i < faceSizeQuadHex; ++i) sortedIndices[i] = indices[i];
1663     ierr = PetscSortInt(faceSizeQuadHex, sortedIndices);CHKERRQ(ierr);
1664     for (iFace = 0; iFace < 6; ++iFace) {
1665       const PetscInt ii = iFace*faceSizeQuadHex;
1666       PetscInt       fVertex, cVertex;
1667 
1668       if ((sortedIndices[0] == faceVerticesQuadHexSorted[ii+0]) &&
1669           (sortedIndices[1] == faceVerticesQuadHexSorted[ii+1]) &&
1670           (sortedIndices[2] == faceVerticesQuadHexSorted[ii+2]) &&
1671           (sortedIndices[3] == faceVerticesQuadHexSorted[ii+3])) {
1672         for (fVertex = 0; fVertex < faceSizeQuadHex; ++fVertex) {
1673           for (cVertex = 0; cVertex < faceSizeQuadHex; ++cVertex) {
1674             if (indices[cVertex] == faceVerticesQuadHex[ii+fVertex]) {
1675               faceVertices[fVertex] = origVertices[cVertex];
1676               break;
1677             }
1678           }
1679         }
1680         found = PETSC_TRUE;
1681         break;
1682       }
1683     }
1684     if (!found) SETERRQ(comm, PETSC_ERR_ARG_WRONG, "Invalid hex crossface");
1685     if (posOriented) *posOriented = PETSC_TRUE;
1686     PetscFunctionReturn(0);
1687   } else SETERRQ(comm, PETSC_ERR_ARG_WRONG, "Unknown cell type for faceOrientation().");
1688   if (!posOrient) {
1689     if (debug) {ierr = PetscPrintf(comm, "  Reversing initial face orientation\n");CHKERRQ(ierr);}
1690     for (f = 0; f < faceSize; ++f) faceVertices[f] = origVertices[faceSize-1 - f];
1691   } else {
1692     if (debug) {ierr = PetscPrintf(comm, "  Keeping initial face orientation\n");CHKERRQ(ierr);}
1693     for (f = 0; f < faceSize; ++f) faceVertices[f] = origVertices[f];
1694   }
1695   if (posOriented) *posOriented = posOrient;
1696   PetscFunctionReturn(0);
1697 }
1698 
1699 #undef __FUNCT__
1700 #define __FUNCT__ "DMPlexGetOrientedFace"
1701 /*
1702     Given a cell and a face, as a set of vertices,
1703       return the oriented face, as a set of vertices, in faceVertices
1704     The orientation is such that the face normal points out of the cell
1705 */
1706 PetscErrorCode DMPlexGetOrientedFace(DM dm, PetscInt cell, PetscInt faceSize, const PetscInt face[], PetscInt numCorners, PetscInt indices[], PetscInt origVertices[], PetscInt faceVertices[], PetscBool *posOriented)
1707 {
1708   const PetscInt *cone = NULL;
1709   PetscInt        coneSize, v, f, v2;
1710   PetscInt        oppositeVertex = -1;
1711   PetscErrorCode  ierr;
1712 
1713   PetscFunctionBegin;
1714   ierr = DMPlexGetConeSize(dm, cell, &coneSize);CHKERRQ(ierr);
1715   ierr = DMPlexGetCone(dm, cell, &cone);CHKERRQ(ierr);
1716   for (v = 0, v2 = 0; v < coneSize; ++v) {
1717     PetscBool found = PETSC_FALSE;
1718 
1719     for (f = 0; f < faceSize; ++f) {
1720       if (face[f] == cone[v]) {
1721         found = PETSC_TRUE; break;
1722       }
1723     }
1724     if (found) {
1725       indices[v2]      = v;
1726       origVertices[v2] = cone[v];
1727       ++v2;
1728     } else {
1729       oppositeVertex = v;
1730     }
1731   }
1732   ierr = DMPlexGetFaceOrientation(dm, cell, numCorners, indices, oppositeVertex, origVertices, faceVertices, posOriented);CHKERRQ(ierr);
1733   PetscFunctionReturn(0);
1734 }
1735 
1736 #undef __FUNCT__
1737 #define __FUNCT__ "DMPlexInsertFace_Internal"
1738 /*
1739   DMPlexInsertFace_Internal - Puts a face into the mesh
1740 
1741   Not collective
1742 
1743   Input Parameters:
1744   + dm              - The DMPlex
1745   . numFaceVertex   - The number of vertices in the face
1746   . faceVertices    - The vertices in the face for dm
1747   . subfaceVertices - The vertices in the face for subdm
1748   . numCorners      - The number of vertices in the cell
1749   . cell            - A cell in dm containing the face
1750   . subcell         - A cell in subdm containing the face
1751   . firstFace       - First face in the mesh
1752   - newFacePoint    - Next face in the mesh
1753 
1754   Output Parameters:
1755   . newFacePoint - Contains next face point number on input, updated on output
1756 
1757   Level: developer
1758 */
1759 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)
1760 {
1761   MPI_Comm        comm;
1762   DM_Plex        *submesh = (DM_Plex*) subdm->data;
1763   const PetscInt *faces;
1764   PetscInt        numFaces, coneSize;
1765   PetscErrorCode  ierr;
1766 
1767   PetscFunctionBegin;
1768   ierr = PetscObjectGetComm((PetscObject)dm,&comm);CHKERRQ(ierr);
1769   ierr = DMPlexGetConeSize(subdm, subcell, &coneSize);CHKERRQ(ierr);
1770   if (coneSize != 1) SETERRQ2(comm, PETSC_ERR_ARG_OUTOFRANGE, "Cone size of cell %d is %d != 1", cell, coneSize);
1771 #if 0
1772   /* Cannot use this because support() has not been constructed yet */
1773   ierr = DMPlexGetJoin(subdm, numFaceVertices, subfaceVertices, &numFaces, &faces);CHKERRQ(ierr);
1774 #else
1775   {
1776     PetscInt f;
1777 
1778     numFaces = 0;
1779     ierr     = DMGetWorkArray(subdm, 1, PETSC_INT, (void **) &faces);CHKERRQ(ierr);
1780     for (f = firstFace; f < *newFacePoint; ++f) {
1781       PetscInt dof, off, d;
1782 
1783       ierr = PetscSectionGetDof(submesh->coneSection, f, &dof);CHKERRQ(ierr);
1784       ierr = PetscSectionGetOffset(submesh->coneSection, f, &off);CHKERRQ(ierr);
1785       /* Yes, I know this is quadratic, but I expect the sizes to be <5 */
1786       for (d = 0; d < dof; ++d) {
1787         const PetscInt p = submesh->cones[off+d];
1788         PetscInt       v;
1789 
1790         for (v = 0; v < numFaceVertices; ++v) {
1791           if (subfaceVertices[v] == p) break;
1792         }
1793         if (v == numFaceVertices) break;
1794       }
1795       if (d == dof) {
1796         numFaces               = 1;
1797         ((PetscInt*) faces)[0] = f;
1798       }
1799     }
1800   }
1801 #endif
1802   if (numFaces > 1) SETERRQ1(comm, PETSC_ERR_ARG_WRONG, "Vertex set had %d faces, not one", numFaces);
1803   else if (numFaces == 1) {
1804     /* Add the other cell neighbor for this face */
1805     ierr = DMPlexSetCone(subdm, subcell, faces);CHKERRQ(ierr);
1806   } else {
1807     PetscInt *indices, *origVertices, *orientedVertices, *orientedSubVertices, v, ov;
1808     PetscBool posOriented;
1809 
1810     ierr                = DMGetWorkArray(subdm, 4*numFaceVertices * sizeof(PetscInt), PETSC_INT, &orientedVertices);CHKERRQ(ierr);
1811     origVertices        = &orientedVertices[numFaceVertices];
1812     indices             = &orientedVertices[numFaceVertices*2];
1813     orientedSubVertices = &orientedVertices[numFaceVertices*3];
1814     ierr                = DMPlexGetOrientedFace(dm, cell, numFaceVertices, faceVertices, numCorners, indices, origVertices, orientedVertices, &posOriented);CHKERRQ(ierr);
1815     /* TODO: I know that routine should return a permutation, not the indices */
1816     for (v = 0; v < numFaceVertices; ++v) {
1817       const PetscInt vertex = faceVertices[v], subvertex = subfaceVertices[v];
1818       for (ov = 0; ov < numFaceVertices; ++ov) {
1819         if (orientedVertices[ov] == vertex) {
1820           orientedSubVertices[ov] = subvertex;
1821           break;
1822         }
1823       }
1824       if (ov == numFaceVertices) SETERRQ1(comm, PETSC_ERR_PLIB, "Could not find face vertex %d in orientated set", vertex);
1825     }
1826     ierr = DMPlexSetCone(subdm, *newFacePoint, orientedSubVertices);CHKERRQ(ierr);
1827     ierr = DMPlexSetCone(subdm, subcell, newFacePoint);CHKERRQ(ierr);
1828     ierr = DMRestoreWorkArray(subdm, 4*numFaceVertices * sizeof(PetscInt), PETSC_INT, &orientedVertices);CHKERRQ(ierr);
1829     ++(*newFacePoint);
1830   }
1831 #if 0
1832   ierr = DMPlexRestoreJoin(subdm, numFaceVertices, subfaceVertices, &numFaces, &faces);CHKERRQ(ierr);
1833 #else
1834   ierr = DMRestoreWorkArray(subdm, 1, PETSC_INT, (void **) &faces);CHKERRQ(ierr);
1835 #endif
1836   PetscFunctionReturn(0);
1837 }
1838 
1839 #undef __FUNCT__
1840 #define __FUNCT__ "DMPlexCreateSubmesh_Uninterpolated"
1841 static PetscErrorCode DMPlexCreateSubmesh_Uninterpolated(DM dm, const char vertexLabelName[], PetscInt value, DM subdm)
1842 {
1843   MPI_Comm        comm;
1844   DMLabel         vertexLabel, subpointMap;
1845   IS              subvertexIS,  subcellIS;
1846   const PetscInt *subVertices, *subCells;
1847   PetscInt        numSubVertices, firstSubVertex, numSubCells;
1848   PetscInt       *subface, maxConeSize, numSubFaces, firstSubFace, newFacePoint, nFV;
1849   PetscInt        vStart, vEnd, c, f;
1850   PetscErrorCode  ierr;
1851 
1852   PetscFunctionBegin;
1853   ierr = PetscObjectGetComm((PetscObject)dm,&comm);CHKERRQ(ierr);
1854   /* Create subpointMap which marks the submesh */
1855   ierr = DMLabelCreate("subpoint_map", &subpointMap);CHKERRQ(ierr);
1856   ierr = DMPlexSetSubpointMap(subdm, subpointMap);CHKERRQ(ierr);
1857   ierr = DMLabelDestroy(&subpointMap);CHKERRQ(ierr);
1858   ierr = DMPlexGetLabel(dm, vertexLabelName, &vertexLabel);CHKERRQ(ierr);
1859   ierr = DMPlexMarkSubmesh_Uninterpolated(dm, vertexLabel, value, subpointMap, &numSubFaces, &nFV, subdm);CHKERRQ(ierr);
1860   /* Setup chart */
1861   ierr = DMLabelGetStratumSize(subpointMap, 0, &numSubVertices);CHKERRQ(ierr);
1862   ierr = DMLabelGetStratumSize(subpointMap, 2, &numSubCells);CHKERRQ(ierr);
1863   ierr = DMPlexSetChart(subdm, 0, numSubCells+numSubFaces+numSubVertices);CHKERRQ(ierr);
1864   ierr = DMPlexSetVTKCellHeight(subdm, 1);CHKERRQ(ierr);
1865   /* Set cone sizes */
1866   firstSubVertex = numSubCells;
1867   firstSubFace   = numSubCells+numSubVertices;
1868   newFacePoint   = firstSubFace;
1869   ierr = DMLabelGetStratumIS(subpointMap, 0, &subvertexIS);CHKERRQ(ierr);
1870   if (subvertexIS) {ierr = ISGetIndices(subvertexIS, &subVertices);CHKERRQ(ierr);}
1871   ierr = DMLabelGetStratumIS(subpointMap, 2, &subcellIS);CHKERRQ(ierr);
1872   if (subcellIS) {ierr = ISGetIndices(subcellIS, &subCells);CHKERRQ(ierr);}
1873   for (c = 0; c < numSubCells; ++c) {
1874     ierr = DMPlexSetConeSize(subdm, c, 1);CHKERRQ(ierr);
1875   }
1876   for (f = firstSubFace; f < firstSubFace+numSubFaces; ++f) {
1877     ierr = DMPlexSetConeSize(subdm, f, nFV);CHKERRQ(ierr);
1878   }
1879   ierr = DMSetUp(subdm);CHKERRQ(ierr);
1880   /* Create face cones */
1881   ierr = DMPlexGetDepthStratum(dm, 0, &vStart, &vEnd);CHKERRQ(ierr);
1882   ierr = DMPlexGetMaxSizes(dm, &maxConeSize, NULL);CHKERRQ(ierr);
1883   ierr = DMGetWorkArray(subdm, maxConeSize, PETSC_INT, (void**) &subface);CHKERRQ(ierr);
1884   for (c = 0; c < numSubCells; ++c) {
1885     const PetscInt cell    = subCells[c];
1886     const PetscInt subcell = c;
1887     PetscInt      *closure = NULL;
1888     PetscInt       closureSize, cl, numCorners = 0, faceSize = 0;
1889 
1890     ierr = DMPlexGetTransitiveClosure(dm, cell, PETSC_TRUE, &closureSize, &closure);CHKERRQ(ierr);
1891     for (cl = 0; cl < closureSize*2; cl += 2) {
1892       const PetscInt point = closure[cl];
1893       PetscInt       subVertex;
1894 
1895       if ((point >= vStart) && (point < vEnd)) {
1896         ++numCorners;
1897         ierr = PetscFindInt(point, numSubVertices, subVertices, &subVertex);CHKERRQ(ierr);
1898         if (subVertex >= 0) {
1899           closure[faceSize] = point;
1900           subface[faceSize] = firstSubVertex+subVertex;
1901           ++faceSize;
1902         }
1903       }
1904     }
1905     if (faceSize > nFV) SETERRQ1(comm, PETSC_ERR_ARG_WRONG, "Invalid submesh: Too many vertices %d of an element on the surface", faceSize);
1906     if (faceSize == nFV) {
1907       ierr = DMPlexInsertFace_Internal(dm, subdm, faceSize, closure, subface, numCorners, cell, subcell, firstSubFace, &newFacePoint);CHKERRQ(ierr);
1908     }
1909     ierr = DMPlexRestoreTransitiveClosure(dm, cell, PETSC_TRUE, &closureSize, &closure);CHKERRQ(ierr);
1910   }
1911   ierr = DMRestoreWorkArray(subdm, maxConeSize, PETSC_INT, (void**) &subface);CHKERRQ(ierr);
1912   ierr = DMPlexSymmetrize(subdm);CHKERRQ(ierr);
1913   ierr = DMPlexStratify(subdm);CHKERRQ(ierr);
1914   /* Build coordinates */
1915   {
1916     PetscSection coordSection, subCoordSection;
1917     Vec          coordinates, subCoordinates;
1918     PetscScalar *coords, *subCoords;
1919     PetscInt     numComp, coordSize, v;
1920 
1921     ierr = DMPlexGetCoordinateSection(dm, &coordSection);CHKERRQ(ierr);
1922     ierr = DMGetCoordinatesLocal(dm, &coordinates);CHKERRQ(ierr);
1923     ierr = DMPlexGetCoordinateSection(subdm, &subCoordSection);CHKERRQ(ierr);
1924     ierr = PetscSectionSetNumFields(subCoordSection, 1);CHKERRQ(ierr);
1925     ierr = PetscSectionGetFieldComponents(coordSection, 0, &numComp);CHKERRQ(ierr);
1926     ierr = PetscSectionSetFieldComponents(subCoordSection, 0, numComp);CHKERRQ(ierr);
1927     ierr = PetscSectionSetChart(subCoordSection, firstSubVertex, firstSubVertex+numSubVertices);CHKERRQ(ierr);
1928     for (v = 0; v < numSubVertices; ++v) {
1929       const PetscInt vertex    = subVertices[v];
1930       const PetscInt subvertex = firstSubVertex+v;
1931       PetscInt       dof;
1932 
1933       ierr = PetscSectionGetDof(coordSection, vertex, &dof);CHKERRQ(ierr);
1934       ierr = PetscSectionSetDof(subCoordSection, subvertex, dof);CHKERRQ(ierr);
1935       ierr = PetscSectionSetFieldDof(subCoordSection, subvertex, 0, dof);CHKERRQ(ierr);
1936     }
1937     ierr = PetscSectionSetUp(subCoordSection);CHKERRQ(ierr);
1938     ierr = PetscSectionGetStorageSize(subCoordSection, &coordSize);CHKERRQ(ierr);
1939     ierr = VecCreate(comm, &subCoordinates);CHKERRQ(ierr);
1940     ierr = VecSetSizes(subCoordinates, coordSize, PETSC_DETERMINE);CHKERRQ(ierr);
1941     ierr = VecSetFromOptions(subCoordinates);CHKERRQ(ierr);
1942     if (coordSize) {
1943       ierr = VecGetArray(coordinates,    &coords);CHKERRQ(ierr);
1944       ierr = VecGetArray(subCoordinates, &subCoords);CHKERRQ(ierr);
1945       for (v = 0; v < numSubVertices; ++v) {
1946         const PetscInt vertex    = subVertices[v];
1947         const PetscInt subvertex = firstSubVertex+v;
1948         PetscInt       dof, off, sdof, soff, d;
1949 
1950         ierr = PetscSectionGetDof(coordSection, vertex, &dof);CHKERRQ(ierr);
1951         ierr = PetscSectionGetOffset(coordSection, vertex, &off);CHKERRQ(ierr);
1952         ierr = PetscSectionGetDof(subCoordSection, subvertex, &sdof);CHKERRQ(ierr);
1953         ierr = PetscSectionGetOffset(subCoordSection, subvertex, &soff);CHKERRQ(ierr);
1954         if (dof != sdof) SETERRQ4(comm, PETSC_ERR_PLIB, "Coordinate dimension %d on subvertex %d, vertex %d should be %d", sdof, subvertex, vertex, dof);
1955         for (d = 0; d < dof; ++d) subCoords[soff+d] = coords[off+d];
1956       }
1957       ierr = VecRestoreArray(coordinates,    &coords);CHKERRQ(ierr);
1958       ierr = VecRestoreArray(subCoordinates, &subCoords);CHKERRQ(ierr);
1959     }
1960     ierr = DMSetCoordinatesLocal(subdm, subCoordinates);CHKERRQ(ierr);
1961     ierr = VecDestroy(&subCoordinates);CHKERRQ(ierr);
1962   }
1963   /* Cleanup */
1964   if (subvertexIS) {ierr = ISRestoreIndices(subvertexIS, &subVertices);CHKERRQ(ierr);}
1965   ierr = ISDestroy(&subvertexIS);CHKERRQ(ierr);
1966   if (subcellIS) {ierr = ISRestoreIndices(subcellIS, &subCells);CHKERRQ(ierr);}
1967   ierr = ISDestroy(&subcellIS);CHKERRQ(ierr);
1968   PetscFunctionReturn(0);
1969 }
1970 
1971 #undef __FUNCT__
1972 #define __FUNCT__ "DMPlexCreateSubmesh_Interpolated"
1973 static PetscErrorCode DMPlexCreateSubmesh_Interpolated(DM dm, const char vertexLabelName[], PetscInt value, DM subdm)
1974 {
1975   MPI_Comm         comm;
1976   DMLabel          subpointMap, vertexLabel;
1977   IS              *subpointIS;
1978   const PetscInt **subpoints;
1979   PetscInt        *numSubPoints, *firstSubPoint, *coneNew;
1980   PetscInt         totSubPoints = 0, maxConeSize, dim, p, d, v;
1981   PetscErrorCode   ierr;
1982 
1983   PetscFunctionBegin;
1984   ierr = PetscObjectGetComm((PetscObject)dm,&comm);CHKERRQ(ierr);
1985   /* Create subpointMap which marks the submesh */
1986   ierr = DMLabelCreate("subpoint_map", &subpointMap);CHKERRQ(ierr);
1987   ierr = DMPlexSetSubpointMap(subdm, subpointMap);CHKERRQ(ierr);
1988   ierr = DMLabelDestroy(&subpointMap);CHKERRQ(ierr);
1989   ierr = DMPlexGetLabel(dm, vertexLabelName, &vertexLabel);CHKERRQ(ierr);
1990   ierr = DMPlexMarkSubmesh_Interpolated(dm, vertexLabel, value, subpointMap, subdm);CHKERRQ(ierr);
1991   /* Setup chart */
1992   ierr = DMPlexGetDimension(dm, &dim);CHKERRQ(ierr);
1993   ierr = PetscMalloc4(dim+1,PetscInt,&numSubPoints,dim+1,PetscInt,&firstSubPoint,dim+1,IS,&subpointIS,dim+1,const PetscInt *,&subpoints);CHKERRQ(ierr);
1994   for (d = 0; d <= dim; ++d) {
1995     ierr = DMLabelGetStratumSize(subpointMap, d, &numSubPoints[d]);CHKERRQ(ierr);
1996     totSubPoints += numSubPoints[d];
1997   }
1998   ierr = DMPlexSetChart(subdm, 0, totSubPoints);CHKERRQ(ierr);
1999   ierr = DMPlexSetVTKCellHeight(subdm, 1);CHKERRQ(ierr);
2000   /* Set cone sizes */
2001   firstSubPoint[dim] = 0;
2002   firstSubPoint[0]   = firstSubPoint[dim] + numSubPoints[dim];
2003   if (dim > 1) {firstSubPoint[dim-1] = firstSubPoint[0]     + numSubPoints[0];}
2004   if (dim > 2) {firstSubPoint[dim-2] = firstSubPoint[dim-1] + numSubPoints[dim-1];}
2005   for (d = 0; d <= dim; ++d) {
2006     ierr = DMLabelGetStratumIS(subpointMap, d, &subpointIS[d]);CHKERRQ(ierr);
2007     ierr = ISGetIndices(subpointIS[d], &subpoints[d]);CHKERRQ(ierr);
2008   }
2009   for (d = 0; d <= dim; ++d) {
2010     for (p = 0; p < numSubPoints[d]; ++p) {
2011       const PetscInt  point    = subpoints[d][p];
2012       const PetscInt  subpoint = firstSubPoint[d] + p;
2013       const PetscInt *cone;
2014       PetscInt        coneSize, coneSizeNew, c, val;
2015 
2016       ierr = DMPlexGetConeSize(dm, point, &coneSize);CHKERRQ(ierr);
2017       ierr = DMPlexSetConeSize(subdm, subpoint, coneSize);CHKERRQ(ierr);
2018       if (d == dim) {
2019         ierr = DMPlexGetCone(dm, point, &cone);CHKERRQ(ierr);
2020         for (c = 0, coneSizeNew = 0; c < coneSize; ++c) {
2021           ierr = DMLabelGetValue(subpointMap, cone[c], &val);CHKERRQ(ierr);
2022           if (val >= 0) coneSizeNew++;
2023         }
2024         ierr = DMPlexSetConeSize(subdm, subpoint, coneSizeNew);CHKERRQ(ierr);
2025       }
2026     }
2027   }
2028   ierr = DMSetUp(subdm);CHKERRQ(ierr);
2029   /* Set cones */
2030   ierr = DMPlexGetMaxSizes(dm, &maxConeSize, NULL);CHKERRQ(ierr);
2031   ierr = PetscMalloc(maxConeSize * sizeof(PetscInt), &coneNew);CHKERRQ(ierr);
2032   for (d = 0; d <= dim; ++d) {
2033     for (p = 0; p < numSubPoints[d]; ++p) {
2034       const PetscInt  point    = subpoints[d][p];
2035       const PetscInt  subpoint = firstSubPoint[d] + p;
2036       const PetscInt *cone, *ornt;
2037       PetscInt        coneSize, subconeSize, coneSizeNew, c, subc;
2038 
2039       ierr = DMPlexGetConeSize(dm, point, &coneSize);CHKERRQ(ierr);
2040       ierr = DMPlexGetConeSize(subdm, subpoint, &subconeSize);CHKERRQ(ierr);
2041       ierr = DMPlexGetCone(dm, point, &cone);CHKERRQ(ierr);
2042       ierr = DMPlexGetConeOrientation(dm, point, &ornt);CHKERRQ(ierr);
2043       for (c = 0, coneSizeNew = 0; c < coneSize; ++c) {
2044         ierr = PetscFindInt(cone[c], numSubPoints[d-1], subpoints[d-1], &subc);CHKERRQ(ierr);
2045         if (subc >= 0) coneNew[coneSizeNew++] = firstSubPoint[d-1] + subc;
2046       }
2047       if (coneSizeNew != subconeSize) SETERRQ2(comm, PETSC_ERR_PLIB, "Number of cone points located %d does not match subcone size %d", coneSizeNew, subconeSize);
2048       ierr = DMPlexSetCone(subdm, subpoint, coneNew);CHKERRQ(ierr);
2049       ierr = DMPlexSetConeOrientation(subdm, subpoint, ornt);CHKERRQ(ierr);
2050     }
2051   }
2052   ierr = PetscFree(coneNew);CHKERRQ(ierr);
2053   ierr = DMPlexSymmetrize(subdm);CHKERRQ(ierr);
2054   ierr = DMPlexStratify(subdm);CHKERRQ(ierr);
2055   /* Build coordinates */
2056   {
2057     PetscSection coordSection, subCoordSection;
2058     Vec          coordinates, subCoordinates;
2059     PetscScalar *coords, *subCoords;
2060     PetscInt     numComp, coordSize;
2061 
2062     ierr = DMPlexGetCoordinateSection(dm, &coordSection);CHKERRQ(ierr);
2063     ierr = DMGetCoordinatesLocal(dm, &coordinates);CHKERRQ(ierr);
2064     ierr = DMPlexGetCoordinateSection(subdm, &subCoordSection);CHKERRQ(ierr);
2065     ierr = PetscSectionSetNumFields(subCoordSection, 1);CHKERRQ(ierr);
2066     ierr = PetscSectionGetFieldComponents(coordSection, 0, &numComp);CHKERRQ(ierr);
2067     ierr = PetscSectionSetFieldComponents(subCoordSection, 0, numComp);CHKERRQ(ierr);
2068     ierr = PetscSectionSetChart(subCoordSection, firstSubPoint[0], firstSubPoint[0]+numSubPoints[0]);CHKERRQ(ierr);
2069     for (v = 0; v < numSubPoints[0]; ++v) {
2070       const PetscInt vertex    = subpoints[0][v];
2071       const PetscInt subvertex = firstSubPoint[0]+v;
2072       PetscInt       dof;
2073 
2074       ierr = PetscSectionGetDof(coordSection, vertex, &dof);CHKERRQ(ierr);
2075       ierr = PetscSectionSetDof(subCoordSection, subvertex, dof);CHKERRQ(ierr);
2076       ierr = PetscSectionSetFieldDof(subCoordSection, subvertex, 0, dof);CHKERRQ(ierr);
2077     }
2078     ierr = PetscSectionSetUp(subCoordSection);CHKERRQ(ierr);
2079     ierr = PetscSectionGetStorageSize(subCoordSection, &coordSize);CHKERRQ(ierr);
2080     ierr = VecCreate(comm, &subCoordinates);CHKERRQ(ierr);
2081     ierr = VecSetSizes(subCoordinates, coordSize, PETSC_DETERMINE);CHKERRQ(ierr);
2082     ierr = VecSetFromOptions(subCoordinates);CHKERRQ(ierr);
2083     ierr = VecGetArray(coordinates,    &coords);CHKERRQ(ierr);
2084     ierr = VecGetArray(subCoordinates, &subCoords);CHKERRQ(ierr);
2085     for (v = 0; v < numSubPoints[0]; ++v) {
2086       const PetscInt vertex    = subpoints[0][v];
2087       const PetscInt subvertex = firstSubPoint[0]+v;
2088       PetscInt dof, off, sdof, soff, d;
2089 
2090       ierr = PetscSectionGetDof(coordSection, vertex, &dof);CHKERRQ(ierr);
2091       ierr = PetscSectionGetOffset(coordSection, vertex, &off);CHKERRQ(ierr);
2092       ierr = PetscSectionGetDof(subCoordSection, subvertex, &sdof);CHKERRQ(ierr);
2093       ierr = PetscSectionGetOffset(subCoordSection, subvertex, &soff);CHKERRQ(ierr);
2094       if (dof != sdof) SETERRQ4(comm, PETSC_ERR_PLIB, "Coordinate dimension %d on subvertex %d, vertex %d should be %d", sdof, subvertex, vertex, dof);
2095       for (d = 0; d < dof; ++d) subCoords[soff+d] = coords[off+d];
2096     }
2097     ierr = VecRestoreArray(coordinates,    &coords);CHKERRQ(ierr);
2098     ierr = VecRestoreArray(subCoordinates, &subCoords);CHKERRQ(ierr);
2099     ierr = DMSetCoordinatesLocal(subdm, subCoordinates);CHKERRQ(ierr);
2100     ierr = VecDestroy(&subCoordinates);CHKERRQ(ierr);
2101   }
2102   /* Cleanup */
2103   for (d = 0; d <= dim; ++d) {
2104     ierr = ISRestoreIndices(subpointIS[d], &subpoints[d]);CHKERRQ(ierr);
2105     ierr = ISDestroy(&subpointIS[d]);CHKERRQ(ierr);
2106   }
2107   ierr = PetscFree4(numSubPoints,firstSubPoint,subpointIS,subpoints);CHKERRQ(ierr);
2108   PetscFunctionReturn(0);
2109 }
2110 
2111 #undef __FUNCT__
2112 #define __FUNCT__ "DMPlexCreateSubmesh"
2113 /*@C
2114   DMPlexCreateSubmesh - Extract a hypersurface from the mesh using vertices defined by a label
2115 
2116   Input Parameters:
2117 + dm           - The original mesh
2118 . vertexLabel  - The DMLabel marking vertices contained in the surface
2119 - value        - The label value to use
2120 
2121   Output Parameter:
2122 . subdm - The surface mesh
2123 
2124   Note: This function produces a DMLabel mapping original points in the submesh to their depth. This can be obtained using DMPlexGetSubpointMap().
2125 
2126   Level: developer
2127 
2128 .seealso: DMPlexGetSubpointMap(), DMPlexGetLabel(), DMLabelSetValue()
2129 @*/
2130 PetscErrorCode DMPlexCreateSubmesh(DM dm, const char vertexLabel[], PetscInt value, DM *subdm)
2131 {
2132   PetscInt       dim, depth;
2133   PetscErrorCode ierr;
2134 
2135   PetscFunctionBegin;
2136   PetscValidHeaderSpecific(dm, DM_CLASSID, 1);
2137   PetscValidCharPointer(vertexLabel, 2);
2138   PetscValidPointer(subdm, 3);
2139   ierr = DMPlexGetDimension(dm, &dim);CHKERRQ(ierr);
2140   ierr = DMPlexGetDepth(dm, &depth);CHKERRQ(ierr);
2141   ierr = DMCreate(PetscObjectComm((PetscObject)dm), subdm);CHKERRQ(ierr);
2142   ierr = DMSetType(*subdm, DMPLEX);CHKERRQ(ierr);
2143   ierr = DMPlexSetDimension(*subdm, dim-1);CHKERRQ(ierr);
2144   if (depth == dim) {
2145     ierr = DMPlexCreateSubmesh_Interpolated(dm, vertexLabel, value, *subdm);CHKERRQ(ierr);
2146   } else {
2147     ierr = DMPlexCreateSubmesh_Uninterpolated(dm, vertexLabel, value, *subdm);CHKERRQ(ierr);
2148   }
2149   PetscFunctionReturn(0);
2150 }
2151 
2152 #undef __FUNCT__
2153 #define __FUNCT__ "DMPlexCreateCohesiveSubmesh_Uninterpolated"
2154 static PetscErrorCode DMPlexCreateCohesiveSubmesh_Uninterpolated(DM dm, PetscBool hasLagrange, DM subdm)
2155 {
2156   MPI_Comm        comm;
2157   DMLabel         subpointMap;
2158   IS              subvertexIS;
2159   const PetscInt *subVertices;
2160   PetscInt        numSubVertices, firstSubVertex, numSubCells, *subCells;
2161   PetscInt       *subface, maxConeSize, numSubFaces, firstSubFace, newFacePoint, nFV;
2162   PetscInt        cMax, c, f;
2163   PetscErrorCode  ierr;
2164 
2165   PetscFunctionBegin;
2166   ierr = PetscObjectGetComm((PetscObject)dm, &comm);CHKERRQ(ierr);
2167   /* Create subpointMap which marks the submesh */
2168   ierr = DMLabelCreate("subpoint_map", &subpointMap);CHKERRQ(ierr);
2169   ierr = DMPlexSetSubpointMap(subdm, subpointMap);CHKERRQ(ierr);
2170   ierr = DMLabelDestroy(&subpointMap);CHKERRQ(ierr);
2171   ierr = DMPlexMarkCohesiveSubmesh_Uninterpolated(dm, hasLagrange, subpointMap, &numSubFaces, &nFV, &subCells, subdm);CHKERRQ(ierr);
2172   /* Setup chart */
2173   ierr = DMLabelGetStratumSize(subpointMap, 0, &numSubVertices);CHKERRQ(ierr);
2174   ierr = DMLabelGetStratumSize(subpointMap, 2, &numSubCells);CHKERRQ(ierr);
2175   ierr = DMPlexSetChart(subdm, 0, numSubCells+numSubFaces+numSubVertices);CHKERRQ(ierr);
2176   ierr = DMPlexSetVTKCellHeight(subdm, 1);CHKERRQ(ierr);
2177   /* Set cone sizes */
2178   firstSubVertex = numSubCells;
2179   firstSubFace   = numSubCells+numSubVertices;
2180   newFacePoint   = firstSubFace;
2181   ierr = DMLabelGetStratumIS(subpointMap, 0, &subvertexIS);CHKERRQ(ierr);
2182   if (subvertexIS) {ierr = ISGetIndices(subvertexIS, &subVertices);CHKERRQ(ierr);}
2183   for (c = 0; c < numSubCells; ++c) {
2184     ierr = DMPlexSetConeSize(subdm, c, 1);CHKERRQ(ierr);
2185   }
2186   for (f = firstSubFace; f < firstSubFace+numSubFaces; ++f) {
2187     ierr = DMPlexSetConeSize(subdm, f, nFV);CHKERRQ(ierr);
2188   }
2189   ierr = DMSetUp(subdm);CHKERRQ(ierr);
2190   /* Create face cones */
2191   ierr = DMPlexGetMaxSizes(dm, &maxConeSize, NULL);CHKERRQ(ierr);
2192   ierr = DMPlexGetHybridBounds(dm, &cMax, NULL, NULL, NULL);CHKERRQ(ierr);
2193   ierr = DMGetWorkArray(subdm, maxConeSize, PETSC_INT, (void**) &subface);CHKERRQ(ierr);
2194   for (c = 0; c < numSubCells; ++c) {
2195     const PetscInt  cell    = subCells[c];
2196     const PetscInt  subcell = c;
2197     const PetscInt *cone, *cells;
2198     PetscInt        numCells, subVertex, p, v;
2199 
2200     if (cell < cMax) continue;
2201     ierr = DMPlexGetCone(dm, cell, &cone);CHKERRQ(ierr);
2202     for (v = 0; v < nFV; ++v) {
2203       ierr = PetscFindInt(cone[v], numSubVertices, subVertices, &subVertex);CHKERRQ(ierr);
2204       subface[v] = firstSubVertex+subVertex;
2205     }
2206     ierr = DMPlexSetCone(subdm, newFacePoint, subface);CHKERRQ(ierr);
2207     ierr = DMPlexSetCone(subdm, subcell, &newFacePoint);CHKERRQ(ierr);
2208     ierr = DMPlexGetJoin(dm, nFV, cone, &numCells, &cells);CHKERRQ(ierr);
2209     if (numCells != 2) SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Cohesive cells should separate two cells");
2210     for (p = 0; p < numCells; ++p) {
2211       PetscInt negsubcell;
2212 
2213       if (cells[p] >= cMax) continue;
2214       /* I know this is a crap search */
2215       for (negsubcell = 0; negsubcell < numSubCells; ++negsubcell) {
2216         if (subCells[negsubcell] == cells[p]) break;
2217       }
2218       if (negsubcell == numSubCells) SETERRQ1(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Could not find negative face neighbor for cohesive cell %d", cell);
2219       ierr = DMPlexSetCone(subdm, negsubcell, &newFacePoint);CHKERRQ(ierr);
2220     }
2221     ierr = DMPlexRestoreJoin(dm, nFV, cone, &numCells, &cells);CHKERRQ(ierr);
2222     ++newFacePoint;
2223   }
2224   ierr = DMRestoreWorkArray(subdm, maxConeSize, PETSC_INT, (void**) &subface);CHKERRQ(ierr);
2225   ierr = DMPlexSymmetrize(subdm);CHKERRQ(ierr);
2226   ierr = DMPlexStratify(subdm);CHKERRQ(ierr);
2227   /* Build coordinates */
2228   {
2229     PetscSection coordSection, subCoordSection;
2230     Vec          coordinates, subCoordinates;
2231     PetscScalar *coords, *subCoords;
2232     PetscInt     numComp, coordSize, v;
2233 
2234     ierr = DMPlexGetCoordinateSection(dm, &coordSection);CHKERRQ(ierr);
2235     ierr = DMGetCoordinatesLocal(dm, &coordinates);CHKERRQ(ierr);
2236     ierr = DMPlexGetCoordinateSection(subdm, &subCoordSection);CHKERRQ(ierr);
2237     ierr = PetscSectionSetNumFields(subCoordSection, 1);CHKERRQ(ierr);
2238     ierr = PetscSectionGetFieldComponents(coordSection, 0, &numComp);CHKERRQ(ierr);
2239     ierr = PetscSectionSetFieldComponents(subCoordSection, 0, numComp);CHKERRQ(ierr);
2240     ierr = PetscSectionSetChart(subCoordSection, firstSubVertex, firstSubVertex+numSubVertices);CHKERRQ(ierr);
2241     for (v = 0; v < numSubVertices; ++v) {
2242       const PetscInt vertex    = subVertices[v];
2243       const PetscInt subvertex = firstSubVertex+v;
2244       PetscInt       dof;
2245 
2246       ierr = PetscSectionGetDof(coordSection, vertex, &dof);CHKERRQ(ierr);
2247       ierr = PetscSectionSetDof(subCoordSection, subvertex, dof);CHKERRQ(ierr);
2248       ierr = PetscSectionSetFieldDof(subCoordSection, subvertex, 0, dof);CHKERRQ(ierr);
2249     }
2250     ierr = PetscSectionSetUp(subCoordSection);CHKERRQ(ierr);
2251     ierr = PetscSectionGetStorageSize(subCoordSection, &coordSize);CHKERRQ(ierr);
2252     ierr = VecCreate(comm, &subCoordinates);CHKERRQ(ierr);
2253     if (coordSize) {
2254       ierr = VecSetSizes(subCoordinates, coordSize, PETSC_DETERMINE);CHKERRQ(ierr);
2255       ierr = VecSetFromOptions(subCoordinates);CHKERRQ(ierr);
2256       ierr = VecGetArray(coordinates,    &coords);CHKERRQ(ierr);
2257       ierr = VecGetArray(subCoordinates, &subCoords);CHKERRQ(ierr);
2258       for (v = 0; v < numSubVertices; ++v) {
2259         const PetscInt vertex    = subVertices[v];
2260         const PetscInt subvertex = firstSubVertex+v;
2261         PetscInt       dof, off, sdof, soff, d;
2262 
2263         ierr = PetscSectionGetDof(coordSection, vertex, &dof);CHKERRQ(ierr);
2264         ierr = PetscSectionGetOffset(coordSection, vertex, &off);CHKERRQ(ierr);
2265         ierr = PetscSectionGetDof(subCoordSection, subvertex, &sdof);CHKERRQ(ierr);
2266         ierr = PetscSectionGetOffset(subCoordSection, subvertex, &soff);CHKERRQ(ierr);
2267         if (dof != sdof) SETERRQ4(comm, PETSC_ERR_PLIB, "Coordinate dimension %d on subvertex %d, vertex %d should be %d", sdof, subvertex, vertex, dof);
2268         for (d = 0; d < dof; ++d) subCoords[soff+d] = coords[off+d];
2269       }
2270       ierr = VecRestoreArray(coordinates,    &coords);CHKERRQ(ierr);
2271       ierr = VecRestoreArray(subCoordinates, &subCoords);CHKERRQ(ierr);
2272     }
2273     ierr = DMSetCoordinatesLocal(subdm, subCoordinates);CHKERRQ(ierr);
2274     ierr = VecDestroy(&subCoordinates);CHKERRQ(ierr);
2275   }
2276   /* Cleanup */
2277   if (subvertexIS) {ierr = ISRestoreIndices(subvertexIS, &subVertices);CHKERRQ(ierr);}
2278   ierr = ISDestroy(&subvertexIS);CHKERRQ(ierr);
2279   ierr = PetscFree(subCells);CHKERRQ(ierr);
2280   PetscFunctionReturn(0);
2281 }
2282 
2283 #undef __FUNCT__
2284 #define __FUNCT__ "DMPlexCreateCohesiveSubmesh_Interpolated"
2285 static PetscErrorCode DMPlexCreateCohesiveSubmesh_Interpolated(DM dm, PetscBool hasLagrange, DM subdm)
2286 {
2287   MPI_Comm         comm;
2288   DMLabel          subpointMap;
2289   IS              *subpointIS;
2290   const PetscInt **subpoints;
2291   PetscInt        *numSubPoints, *firstSubPoint, *coneNew;
2292   PetscInt         totSubPoints = 0, maxConeSize, dim, p, d, v;
2293   PetscErrorCode   ierr;
2294 
2295   PetscFunctionBegin;
2296   ierr = PetscObjectGetComm((PetscObject)dm,&comm);CHKERRQ(ierr);
2297   /* Create subpointMap which marks the submesh */
2298   ierr = DMLabelCreate("subpoint_map", &subpointMap);CHKERRQ(ierr);
2299   ierr = DMPlexSetSubpointMap(subdm, subpointMap);CHKERRQ(ierr);
2300   ierr = DMLabelDestroy(&subpointMap);CHKERRQ(ierr);
2301   ierr = DMPlexMarkCohesiveSubmesh_Interpolated(dm, hasLagrange, subpointMap, subdm);CHKERRQ(ierr);
2302   /* Setup chart */
2303   ierr = DMPlexGetDimension(dm, &dim);CHKERRQ(ierr);
2304   ierr = PetscMalloc4(dim+1,PetscInt,&numSubPoints,dim+1,PetscInt,&firstSubPoint,dim+1,IS,&subpointIS,dim+1,const PetscInt *,&subpoints);CHKERRQ(ierr);
2305   for (d = 0; d <= dim; ++d) {
2306     ierr = DMLabelGetStratumSize(subpointMap, d, &numSubPoints[d]);CHKERRQ(ierr);
2307     totSubPoints += numSubPoints[d];
2308   }
2309   ierr = DMPlexSetChart(subdm, 0, totSubPoints);CHKERRQ(ierr);
2310   ierr = DMPlexSetVTKCellHeight(subdm, 1);CHKERRQ(ierr);
2311   /* Set cone sizes */
2312   firstSubPoint[dim] = 0;
2313   firstSubPoint[0]   = firstSubPoint[dim] + numSubPoints[dim];
2314   if (dim > 1) {firstSubPoint[dim-1] = firstSubPoint[0]     + numSubPoints[0];}
2315   if (dim > 2) {firstSubPoint[dim-2] = firstSubPoint[dim-1] + numSubPoints[dim-1];}
2316   for (d = 0; d <= dim; ++d) {
2317     ierr = DMLabelGetStratumIS(subpointMap, d, &subpointIS[d]);CHKERRQ(ierr);
2318     ierr = ISGetIndices(subpointIS[d], &subpoints[d]);CHKERRQ(ierr);
2319   }
2320   for (d = 0; d <= dim; ++d) {
2321     for (p = 0; p < numSubPoints[d]; ++p) {
2322       const PetscInt  point    = subpoints[d][p];
2323       const PetscInt  subpoint = firstSubPoint[d] + p;
2324       const PetscInt *cone;
2325       PetscInt        coneSize, coneSizeNew, c, val;
2326 
2327       ierr = DMPlexGetConeSize(dm, point, &coneSize);CHKERRQ(ierr);
2328       ierr = DMPlexSetConeSize(subdm, subpoint, coneSize);CHKERRQ(ierr);
2329       if (d == dim) {
2330         ierr = DMPlexGetCone(dm, point, &cone);CHKERRQ(ierr);
2331         for (c = 0, coneSizeNew = 0; c < coneSize; ++c) {
2332           ierr = DMLabelGetValue(subpointMap, cone[c], &val);CHKERRQ(ierr);
2333           if (val >= 0) coneSizeNew++;
2334         }
2335         ierr = DMPlexSetConeSize(subdm, subpoint, coneSizeNew);CHKERRQ(ierr);
2336       }
2337     }
2338   }
2339   ierr = DMSetUp(subdm);CHKERRQ(ierr);
2340   /* Set cones */
2341   ierr = DMPlexGetMaxSizes(dm, &maxConeSize, NULL);CHKERRQ(ierr);
2342   ierr = PetscMalloc(maxConeSize * sizeof(PetscInt), &coneNew);CHKERRQ(ierr);
2343   for (d = 0; d <= dim; ++d) {
2344     for (p = 0; p < numSubPoints[d]; ++p) {
2345       const PetscInt  point    = subpoints[d][p];
2346       const PetscInt  subpoint = firstSubPoint[d] + p;
2347       const PetscInt *cone;
2348       PetscInt        coneSize, subconeSize, coneSizeNew, c, subc;
2349 
2350       ierr = DMPlexGetConeSize(dm, point, &coneSize);CHKERRQ(ierr);
2351       ierr = DMPlexGetConeSize(subdm, subpoint, &subconeSize);CHKERRQ(ierr);
2352       ierr = DMPlexGetCone(dm, point, &cone);CHKERRQ(ierr);
2353       for (c = 0, coneSizeNew = 0; c < coneSize; ++c) {
2354         ierr = PetscFindInt(cone[c], numSubPoints[d-1], subpoints[d-1], &subc);CHKERRQ(ierr);
2355         if (subc >= 0) coneNew[coneSizeNew++] = firstSubPoint[d-1] + subc;
2356       }
2357       if (coneSizeNew != subconeSize) SETERRQ2(comm, PETSC_ERR_PLIB, "Number of cone points located %d does not match subcone size %d", coneSizeNew, subconeSize);
2358       ierr = DMPlexSetCone(subdm, subpoint, coneNew);CHKERRQ(ierr);
2359     }
2360   }
2361   ierr = PetscFree(coneNew);CHKERRQ(ierr);
2362   ierr = DMPlexSymmetrize(subdm);CHKERRQ(ierr);
2363   ierr = DMPlexStratify(subdm);CHKERRQ(ierr);
2364   /* Build coordinates */
2365   {
2366     PetscSection coordSection, subCoordSection;
2367     Vec          coordinates, subCoordinates;
2368     PetscScalar *coords, *subCoords;
2369     PetscInt     numComp, coordSize;
2370 
2371     ierr = DMPlexGetCoordinateSection(dm, &coordSection);CHKERRQ(ierr);
2372     ierr = DMGetCoordinatesLocal(dm, &coordinates);CHKERRQ(ierr);
2373     ierr = DMPlexGetCoordinateSection(subdm, &subCoordSection);CHKERRQ(ierr);
2374     ierr = PetscSectionSetNumFields(subCoordSection, 1);CHKERRQ(ierr);
2375     ierr = PetscSectionGetFieldComponents(coordSection, 0, &numComp);CHKERRQ(ierr);
2376     ierr = PetscSectionSetFieldComponents(subCoordSection, 0, numComp);CHKERRQ(ierr);
2377     ierr = PetscSectionSetChart(subCoordSection, firstSubPoint[0], firstSubPoint[0]+numSubPoints[0]);CHKERRQ(ierr);
2378     for (v = 0; v < numSubPoints[0]; ++v) {
2379       const PetscInt vertex    = subpoints[0][v];
2380       const PetscInt subvertex = firstSubPoint[0]+v;
2381       PetscInt       dof;
2382 
2383       ierr = PetscSectionGetDof(coordSection, vertex, &dof);CHKERRQ(ierr);
2384       ierr = PetscSectionSetDof(subCoordSection, subvertex, dof);CHKERRQ(ierr);
2385       ierr = PetscSectionSetFieldDof(subCoordSection, subvertex, 0, dof);CHKERRQ(ierr);
2386     }
2387     ierr = PetscSectionSetUp(subCoordSection);CHKERRQ(ierr);
2388     ierr = PetscSectionGetStorageSize(subCoordSection, &coordSize);CHKERRQ(ierr);
2389     ierr = VecCreate(comm, &subCoordinates);CHKERRQ(ierr);
2390     ierr = VecSetSizes(subCoordinates, coordSize, PETSC_DETERMINE);CHKERRQ(ierr);
2391     ierr = VecSetFromOptions(subCoordinates);CHKERRQ(ierr);
2392     ierr = VecGetArray(coordinates,    &coords);CHKERRQ(ierr);
2393     ierr = VecGetArray(subCoordinates, &subCoords);CHKERRQ(ierr);
2394     for (v = 0; v < numSubPoints[0]; ++v) {
2395       const PetscInt vertex    = subpoints[0][v];
2396       const PetscInt subvertex = firstSubPoint[0]+v;
2397       PetscInt dof, off, sdof, soff, d;
2398 
2399       ierr = PetscSectionGetDof(coordSection, vertex, &dof);CHKERRQ(ierr);
2400       ierr = PetscSectionGetOffset(coordSection, vertex, &off);CHKERRQ(ierr);
2401       ierr = PetscSectionGetDof(subCoordSection, subvertex, &sdof);CHKERRQ(ierr);
2402       ierr = PetscSectionGetOffset(subCoordSection, subvertex, &soff);CHKERRQ(ierr);
2403       if (dof != sdof) SETERRQ4(comm, PETSC_ERR_PLIB, "Coordinate dimension %d on subvertex %d, vertex %d should be %d", sdof, subvertex, vertex, dof);
2404       for (d = 0; d < dof; ++d) subCoords[soff+d] = coords[off+d];
2405     }
2406     ierr = VecRestoreArray(coordinates,    &coords);CHKERRQ(ierr);
2407     ierr = VecRestoreArray(subCoordinates, &subCoords);CHKERRQ(ierr);
2408     ierr = DMSetCoordinatesLocal(subdm, subCoordinates);CHKERRQ(ierr);
2409     ierr = VecDestroy(&subCoordinates);CHKERRQ(ierr);
2410   }
2411   /* Cleanup */
2412   for (d = 0; d <= dim; ++d) {
2413     ierr = ISRestoreIndices(subpointIS[d], &subpoints[d]);CHKERRQ(ierr);
2414     ierr = ISDestroy(&subpointIS[d]);CHKERRQ(ierr);
2415   }
2416   ierr = PetscFree4(numSubPoints,firstSubPoint,subpointIS,subpoints);CHKERRQ(ierr);
2417   PetscFunctionReturn(0);
2418 }
2419 
2420 #undef __FUNCT__
2421 #define __FUNCT__ "DMPlexCreateCohesiveSubmesh"
2422 /*
2423   DMPlexCreateCohesiveSubmesh - Extract from a mesh with cohesive cells the hypersurface defined by one face of the cells.
2424 
2425   Input Parameters:
2426 + dm          - The original mesh
2427 - hasLagrange - The mesh has Lagrange unknowns in the cohesive cells
2428 
2429   Output Parameter:
2430 . subdm - The surface mesh
2431 
2432   Note: This function produces a DMLabel mapping original points in the submesh to their depth. This can be obtained using DMPlexGetSubpointMap().
2433 
2434   Level: developer
2435 
2436 .seealso: DMPlexGetSubpointMap(), DMPlexCreateSubmesh()
2437 */
2438 PetscErrorCode DMPlexCreateCohesiveSubmesh(DM dm, PetscBool hasLagrange, DM *subdm)
2439 {
2440   PetscInt       dim, depth;
2441   PetscErrorCode ierr;
2442 
2443   PetscFunctionBegin;
2444   PetscValidHeaderSpecific(dm, DM_CLASSID, 1);
2445   PetscValidPointer(subdm, 3);
2446   ierr = DMPlexGetDimension(dm, &dim);CHKERRQ(ierr);
2447   ierr = DMPlexGetDepth(dm, &depth);CHKERRQ(ierr);
2448   ierr = DMCreate(PetscObjectComm((PetscObject)dm), subdm);CHKERRQ(ierr);
2449   ierr = DMSetType(*subdm, DMPLEX);CHKERRQ(ierr);
2450   ierr = DMPlexSetDimension(*subdm, dim-1);CHKERRQ(ierr);
2451   if (depth == dim) {
2452     ierr = DMPlexCreateCohesiveSubmesh_Interpolated(dm, hasLagrange, *subdm);CHKERRQ(ierr);
2453   } else {
2454     ierr = DMPlexCreateCohesiveSubmesh_Uninterpolated(dm, hasLagrange, *subdm);CHKERRQ(ierr);
2455   }
2456   PetscFunctionReturn(0);
2457 }
2458 
2459 #undef __FUNCT__
2460 #define __FUNCT__ "DMPlexGetSubpointMap"
2461 /*@
2462   DMPlexGetSubpointMap - Returns a DMLabel with point dimension as values
2463 
2464   Input Parameter:
2465 . dm - The submesh DM
2466 
2467   Output Parameter:
2468 . subpointMap - The DMLabel of all the points from the original mesh in this submesh, or NULL if this is not a submesh
2469 
2470   Level: developer
2471 
2472 .seealso: DMPlexCreateSubmesh(), DMPlexCreateSubpointIS()
2473 @*/
2474 PetscErrorCode DMPlexGetSubpointMap(DM dm, DMLabel *subpointMap)
2475 {
2476   DM_Plex *mesh = (DM_Plex*) dm->data;
2477 
2478   PetscFunctionBegin;
2479   PetscValidHeaderSpecific(dm, DM_CLASSID, 1);
2480   PetscValidPointer(subpointMap, 2);
2481   *subpointMap = mesh->subpointMap;
2482   PetscFunctionReturn(0);
2483 }
2484 
2485 #undef __FUNCT__
2486 #define __FUNCT__ "DMPlexSetSubpointMap"
2487 /* Note: Should normally not be called by the user, since it is set in DMPlexCreateSubmesh() */
2488 PetscErrorCode DMPlexSetSubpointMap(DM dm, DMLabel subpointMap)
2489 {
2490   DM_Plex       *mesh = (DM_Plex *) dm->data;
2491   DMLabel        tmp;
2492   PetscErrorCode ierr;
2493 
2494   PetscFunctionBegin;
2495   PetscValidHeaderSpecific(dm, DM_CLASSID, 1);
2496   tmp  = mesh->subpointMap;
2497   mesh->subpointMap = subpointMap;
2498   ++mesh->subpointMap->refct;
2499   ierr = DMLabelDestroy(&tmp);CHKERRQ(ierr);
2500   PetscFunctionReturn(0);
2501 }
2502 
2503 #undef __FUNCT__
2504 #define __FUNCT__ "DMPlexCreateSubpointIS"
2505 /*@
2506   DMPlexCreateSubpointIS - Creates an IS covering the entire subdm chart with the original points as data
2507 
2508   Input Parameter:
2509 . dm - The submesh DM
2510 
2511   Output Parameter:
2512 . subpointIS - The IS of all the points from the original mesh in this submesh, or NULL if this is not a submesh
2513 
2514   Note: This is IS is guaranteed to be sorted by the construction of the submesh
2515 
2516   Level: developer
2517 
2518 .seealso: DMPlexCreateSubmesh(), DMPlexGetSubpointMap()
2519 @*/
2520 PetscErrorCode DMPlexCreateSubpointIS(DM dm, IS *subpointIS)
2521 {
2522   MPI_Comm        comm;
2523   DMLabel         subpointMap;
2524   IS              is;
2525   const PetscInt *opoints;
2526   PetscInt       *points, *depths;
2527   PetscInt        depth, depStart, depEnd, d, pStart, pEnd, p, n, off;
2528   PetscErrorCode  ierr;
2529 
2530   PetscFunctionBegin;
2531   PetscValidHeaderSpecific(dm, DM_CLASSID, 1);
2532   PetscValidPointer(subpointIS, 2);
2533   ierr = PetscObjectGetComm((PetscObject)dm,&comm);CHKERRQ(ierr);
2534   *subpointIS = NULL;
2535   ierr = DMPlexGetSubpointMap(dm, &subpointMap);CHKERRQ(ierr);
2536   if (subpointMap) {
2537     ierr = DMPlexGetDepth(dm, &depth);CHKERRQ(ierr);
2538     ierr = DMPlexGetChart(dm, &pStart, &pEnd);CHKERRQ(ierr);
2539     if (pStart) SETERRQ1(comm, PETSC_ERR_ARG_WRONG, "Submeshes must start the point numbering at 0, not %d", pStart);
2540     ierr = DMGetWorkArray(dm, depth+1, PETSC_INT, &depths);CHKERRQ(ierr);
2541     depths[0] = depth;
2542     depths[1] = 0;
2543     for(d = 2; d <= depth; ++d) {depths[d] = depth+1 - d;}
2544     ierr = PetscMalloc(pEnd * sizeof(PetscInt), &points);CHKERRQ(ierr);
2545     for(d = 0, off = 0; d <= depth; ++d) {
2546       const PetscInt dep = depths[d];
2547 
2548       ierr = DMPlexGetDepthStratum(dm, dep, &depStart, &depEnd);CHKERRQ(ierr);
2549       ierr = DMLabelGetStratumSize(subpointMap, dep, &n);CHKERRQ(ierr);
2550       if (((d < 2) && (depth > 1)) || (d == 1)) { /* Only check vertices and cells for now since the map is broken for others */
2551         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);
2552       } else {
2553         if (!n) {
2554           if (d == 0) {
2555             /* Missing cells */
2556             for(p = 0; p < depEnd-depStart; ++p, ++off) points[off] = -1;
2557           } else {
2558             /* Missing faces */
2559             for(p = 0; p < depEnd-depStart; ++p, ++off) points[off] = PETSC_MAX_INT;
2560           }
2561         }
2562       }
2563       if (n) {
2564         ierr = DMLabelGetStratumIS(subpointMap, dep, &is);CHKERRQ(ierr);
2565         ierr = ISGetIndices(is, &opoints);CHKERRQ(ierr);
2566         for(p = 0; p < n; ++p, ++off) points[off] = opoints[p];
2567         ierr = ISRestoreIndices(is, &opoints);CHKERRQ(ierr);
2568         ierr = ISDestroy(&is);CHKERRQ(ierr);
2569       }
2570     }
2571     ierr = DMRestoreWorkArray(dm, depth+1, PETSC_INT, &depths);CHKERRQ(ierr);
2572     if (off != pEnd) SETERRQ2(comm, PETSC_ERR_ARG_WRONG, "The number of mapped submesh points %d should be %d", off, pEnd);
2573     ierr = ISCreateGeneral(comm, pEnd, points, PETSC_OWN_POINTER, subpointIS);CHKERRQ(ierr);
2574   }
2575   PetscFunctionReturn(0);
2576 }
2577