xref: /petsc/src/dm/impls/plex/plexsubmesh.c (revision bb55d31473ead100f96c2c78984730b38f9a9dd7)
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         /* Face support */
689         for (s = 0; s < supportSize; ++s) {
690           PetscInt val;
691 
692           ierr = DMLabelGetValue(label, support[s], &val);CHKERRQ(ierr);
693           if (val < 0) {
694             /* Split old face:   Replace negative side cell with cohesive cell */
695              ierr = DMPlexInsertSupport(sdm, newp, s, ccell);CHKERRQ(ierr);
696           } else {
697             /* Split new face:   Replace positive side cell with cohesive cell */
698             ierr = DMPlexInsertSupport(sdm, splitp, s, ccell);CHKERRQ(ierr);
699             /* Get orientation for cohesive face */
700             {
701               const PetscInt *ncone, *nconeO;
702               PetscInt        nconeSize, nc;
703 
704               ierr = DMPlexGetConeSize(dm, support[s], &nconeSize);CHKERRQ(ierr);
705               ierr = DMPlexGetCone(dm, support[s], &ncone);CHKERRQ(ierr);
706               ierr = DMPlexGetConeOrientation(dm, support[s], &nconeO);CHKERRQ(ierr);
707               for (nc = 0; nc < nconeSize; ++nc) {
708                 if (ncone[nc] == oldp) {
709                   coneONew[0] = nconeO[nc];
710                   break;
711                 }
712               }
713               if (nc >= nconeSize) SETERRQ2(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Could not locate face %d in neighboring cell %d", oldp, support[s]);
714             }
715           }
716         }
717         /* Cohesive cell:    Old and new split face, then new cohesive edges */
718         coneNew[0] = newp;   /* Extracted negative side orentation above */
719         coneNew[1] = splitp; coneONew[1] = coneONew[0];
720         for (q = 0; q < coneSize; ++q) {
721           coneNew[2+q]  = (pMaxNew[1] - pMaxNew[dim-2]) + (depthShift[1] - depthShift[0]) + coneNew[2+q];
722           coneONew[2+q] = 0;
723         }
724         ierr = DMPlexSetCone(sdm, ccell, coneNew);CHKERRQ(ierr);
725         ierr = DMPlexSetConeOrientation(sdm, ccell, coneONew);CHKERRQ(ierr);
726       } else if (dep == 0) {
727         const PetscInt cedge = pMaxNew[1] + (depthShift[1] - depthShift[0]) + p;
728 
729         /* Split old vertex: Edges in old split faces and new cohesive edge */
730         for (e = 0, q = 0; e < supportSize; ++e) {
731           PetscInt val;
732 
733           ierr = DMLabelGetValue(label, support[e], &val);CHKERRQ(ierr);
734           if ((val == 1) || (val == (shift + 1))) {
735             supportNew[q++] = depthOffset[1] + support[e];
736           }
737         }
738         supportNew[q] = cedge;
739 
740         ierr = DMPlexSetSupport(sdm, newp, supportNew);CHKERRQ(ierr);
741         /* Split new vertex: Edges in new split faces and new cohesive edge */
742         for (e = 0, q = 0; e < supportSize; ++e) {
743           PetscInt val, edge;
744 
745           ierr = DMLabelGetValue(label, support[e], &val);CHKERRQ(ierr);
746           if (val == 1) {
747             ierr = PetscFindInt(support[e], numSplitPoints[1], splitPoints[1], &edge);CHKERRQ(ierr);
748             if (edge < 0) SETERRQ1(comm, PETSC_ERR_ARG_WRONG, "Edge %d is not a split edge", support[e]);
749             supportNew[q++] = pMaxNew[1] + edge;
750           } else if (val == -(shift + 1)) {
751             supportNew[q++] = depthOffset[1] + support[e];
752           }
753         }
754         supportNew[q] = cedge;
755         ierr          = DMPlexSetSupport(sdm, splitp, supportNew);CHKERRQ(ierr);
756         /* Cohesive edge:    Old and new split vertex, punting on support */
757         coneNew[0] = newp;
758         coneNew[1] = splitp;
759         ierr       = DMPlexSetCone(sdm, cedge, coneNew);CHKERRQ(ierr);
760       } else if (dep == dim-2) {
761         /* Split old edge:   old vertices in cone so no change */
762         /* Split new edge:   new vertices in cone */
763         for (q = 0; q < coneSize; ++q) {
764           ierr = PetscFindInt(cone[q], numSplitPoints[dim-3], splitPoints[dim-3], &v);CHKERRQ(ierr);
765 
766           coneNew[q] = pMaxNew[dim-3] + v;
767         }
768         ierr = DMPlexSetCone(sdm, splitp, coneNew);CHKERRQ(ierr);
769         /* Split old edge: Faces in positive side cells and old split faces */
770         for (e = 0, q = 0; e < supportSize; ++e) {
771           PetscInt val;
772 
773           ierr = DMLabelGetValue(label, support[e], &val);CHKERRQ(ierr);
774           if ((val == dim-1) || (val == (shift + dim-1))) {
775             supportNew[q++] = depthOffset[dim-1] + support[e];
776           }
777         }
778         ierr = DMPlexSetSupport(sdm, newp, supportNew);CHKERRQ(ierr);
779         /* Split new edge: Faces in negative side cells and new split faces */
780         for (e = 0, q = 0; e < supportSize; ++e) {
781           PetscInt val, face;
782 
783           ierr = DMLabelGetValue(label, support[e], &val);CHKERRQ(ierr);
784           if (val == dim-1) {
785             ierr = PetscFindInt(support[e], numSplitPoints[dim-1], splitPoints[dim-1], &face);CHKERRQ(ierr);
786             if (face < 0) SETERRQ1(comm, PETSC_ERR_ARG_WRONG, "Face %d is not a split face", support[e]);
787             supportNew[q++] = pMaxNew[dim-1] + face;
788           } else if (val == -(shift + dim-1)) {
789             supportNew[q++] = depthOffset[dim-1] + support[e];
790           }
791         }
792         ierr = DMPlexSetSupport(sdm, splitp, supportNew);CHKERRQ(ierr);
793       }
794     }
795   }
796   /* Step 6b: Replace split points in negative side cones */
797   for (sp = 0; sp < numSP; ++sp) {
798     PetscInt        dep = values[sp];
799     IS              pIS;
800     PetscInt        numPoints;
801     const PetscInt *points;
802 
803     if (dep >= 0) continue;
804     ierr = DMLabelGetStratumIS(label, dep, &pIS);CHKERRQ(ierr);
805     if (!pIS) continue;
806     dep  = -dep - shift;
807     ierr = ISGetLocalSize(pIS, &numPoints);CHKERRQ(ierr);
808     ierr = ISGetIndices(pIS, &points);CHKERRQ(ierr);
809     for (p = 0; p < numPoints; ++p) {
810       const PetscInt  oldp = points[p];
811       const PetscInt  newp = depthOffset[dep] + oldp;
812       const PetscInt *cone;
813       PetscInt        coneSize, c;
814       PetscBool       replaced = PETSC_FALSE;
815 
816       /* Negative edge: replace split vertex */
817       /* Negative cell: replace split face */
818       ierr = DMPlexGetConeSize(sdm, newp, &coneSize);CHKERRQ(ierr);
819       ierr = DMPlexGetCone(sdm, newp, &cone);CHKERRQ(ierr);
820       for (c = 0; c < coneSize; ++c) {
821         const PetscInt coldp = cone[c] - depthOffset[dep-1];
822         PetscInt       csplitp, cp, val;
823 
824         ierr = DMLabelGetValue(label, coldp, &val);CHKERRQ(ierr);
825         if (val == dep-1) {
826           ierr = PetscFindInt(coldp, numSplitPoints[dep-1], splitPoints[dep-1], &cp);CHKERRQ(ierr);
827           if (cp < 0) SETERRQ2(comm, PETSC_ERR_ARG_WRONG, "Point %d is not a split point of dimension %d", oldp, dep-1);
828           csplitp  = pMaxNew[dep-1] + cp;
829           ierr     = DMPlexInsertCone(sdm, newp, c, csplitp);CHKERRQ(ierr);
830           replaced = PETSC_TRUE;
831         }
832       }
833       if (!replaced) SETERRQ1(comm, PETSC_ERR_ARG_WRONG, "The cone of point %d does not contain split points", oldp);
834     }
835     ierr = ISRestoreIndices(pIS, &points);CHKERRQ(ierr);
836     ierr = ISDestroy(&pIS);CHKERRQ(ierr);
837   }
838   /* Step 7: Stratify */
839   ierr = DMPlexStratify(sdm);CHKERRQ(ierr);
840   /* Step 8: Coordinates */
841   ierr = DMPlexShiftCoordinates_Internal(dm, depthShift, sdm);CHKERRQ(ierr);
842   ierr = DMPlexGetCoordinateSection(sdm, &coordSection);CHKERRQ(ierr);
843   ierr = DMGetCoordinatesLocal(sdm, &coordinates);CHKERRQ(ierr);
844   ierr = VecGetArray(coordinates, &coords);CHKERRQ(ierr);
845   for (v = 0; v < (numSplitPoints ? numSplitPoints[0] : 0); ++v) {
846     const PetscInt newp   = depthOffset[0] + splitPoints[0][v];
847     const PetscInt splitp = pMaxNew[0] + v;
848     PetscInt       dof, off, soff, d;
849 
850     ierr = PetscSectionGetDof(coordSection, newp, &dof);CHKERRQ(ierr);
851     ierr = PetscSectionGetOffset(coordSection, newp, &off);CHKERRQ(ierr);
852     ierr = PetscSectionGetOffset(coordSection, splitp, &soff);CHKERRQ(ierr);
853     for (d = 0; d < dof; ++d) coords[soff+d] = coords[off+d];
854   }
855   ierr = VecRestoreArray(coordinates, &coords);CHKERRQ(ierr);
856   /* Step 9: SF, if I can figure this out we can split the mesh in parallel */
857   ierr = DMPlexShiftSF_Internal(dm, depthShift, sdm);CHKERRQ(ierr);
858   /* Step 10: Labels */
859   ierr = DMPlexShiftLabels_Internal(dm, depthShift, sdm);CHKERRQ(ierr);
860   ierr = DMPlexGetNumLabels(sdm, &numLabels);CHKERRQ(ierr);
861   for (dep = 0; dep <= depth; ++dep) {
862     for (p = 0; p < numSplitPoints[dep]; ++p) {
863       const PetscInt newp   = depthOffset[dep] + splitPoints[dep][p];
864       const PetscInt splitp = pMaxNew[dep] + p;
865       PetscInt       l;
866 
867       for (l = 0; l < numLabels; ++l) {
868         DMLabel     mlabel;
869         const char *lname;
870         PetscInt    val;
871 
872         ierr = DMPlexGetLabelName(sdm, l, &lname);CHKERRQ(ierr);
873         ierr = DMPlexGetLabel(sdm, lname, &mlabel);CHKERRQ(ierr);
874         ierr = DMLabelGetValue(mlabel, newp, &val);CHKERRQ(ierr);
875         if (val >= 0) {
876           ierr = DMLabelSetValue(mlabel, splitp, val);CHKERRQ(ierr);
877           if (dep == 0) {
878             const PetscInt cedge = pMaxNew[1] + (depthShift[1] - depthShift[0]) + p;
879             ierr = DMLabelSetValue(mlabel, cedge, val);CHKERRQ(ierr);
880           }
881         }
882       }
883     }
884   }
885   for (sp = 0; sp < numSP; ++sp) {
886     const PetscInt dep = values[sp];
887 
888     if ((dep < 0) || (dep > depth)) continue;
889     if (pointIS[dep]) {ierr = ISRestoreIndices(pointIS[dep], &splitPoints[dep]);CHKERRQ(ierr);}
890     ierr = ISDestroy(&pointIS[dep]);CHKERRQ(ierr);
891   }
892   if (label) {
893     ierr = ISRestoreIndices(valueIS, &values);CHKERRQ(ierr);
894     ierr = ISDestroy(&valueIS);CHKERRQ(ierr);
895   }
896   ierr = DMPlexGetChart(sdm, NULL, &pEnd);CHKERRQ(ierr);
897   if (depth > 0) pMaxNew[0] += depthShift[0];        /* Account for shadow vertices */
898   if (depth > 1) pMaxNew[1]  = pEnd - depthShift[0]; /* There is a hybrid edge for every shadow vertex */
899   if (depth > 2) pMaxNew[2]  = -1;                   /* There are no hybrid faces */
900   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);
901   ierr = PetscFree6(depthShift, depthOffset, pMaxNew, coneNew, coneONew, supportNew);CHKERRQ(ierr);
902   ierr = PetscFree3(pointIS, numSplitPoints, splitPoints);CHKERRQ(ierr);
903   PetscFunctionReturn(0);
904 }
905 
906 #undef __FUNCT__
907 #define __FUNCT__ "DMPlexConstructCohesiveCells"
908 /*@C
909   DMPlexConstructCohesiveCells - Construct cohesive cells which split the face along an internal interface
910 
911   Collective on dm
912 
913   Input Parameters:
914 + dm - The original DM
915 - labelName - The label specifying the boundary faces (this could be auto-generated)
916 
917   Output Parameters:
918 - dmSplit - The new DM
919 
920   Level: developer
921 
922 .seealso: DMCreate(), DMPlexLabelCohesiveComplete()
923 @*/
924 PetscErrorCode DMPlexConstructCohesiveCells(DM dm, DMLabel label, DM *dmSplit)
925 {
926   DM             sdm;
927   PetscInt       dim;
928   PetscErrorCode ierr;
929 
930   PetscFunctionBegin;
931   PetscValidHeaderSpecific(dm, DM_CLASSID, 1);
932   PetscValidPointer(dmSplit, 4);
933   ierr = DMCreate(PetscObjectComm((PetscObject)dm), &sdm);CHKERRQ(ierr);
934   ierr = DMSetType(sdm, DMPLEX);CHKERRQ(ierr);
935   ierr = DMPlexGetDimension(dm, &dim);CHKERRQ(ierr);
936   ierr = DMPlexSetDimension(sdm, dim);CHKERRQ(ierr);
937   switch (dim) {
938   case 2:
939   case 3:
940     ierr = DMPlexConstructCohesiveCells_Internal(dm, label, sdm);CHKERRQ(ierr);
941     break;
942   default:
943     SETERRQ1(PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_OUTOFRANGE, "Cannot construct cohesive cells for dimension %d", dim);
944   }
945   *dmSplit = sdm;
946   PetscFunctionReturn(0);
947 }
948 
949 #undef __FUNCT__
950 #define __FUNCT__ "DMPlexLabelCohesiveComplete"
951 /*@
952   DMPlexLabelCohesiveComplete - Starting with a label marking vertices on an internal surface, we add all other mesh pieces
953   to complete the surface
954 
955   Input Parameters:
956 + dm - The DM
957 . label - A DMLabel marking the surface vertices
958 . flip  - Flag to flip the submesh normal and replace points on the other side
959 - subdm - The subDM associated with the label, or NULL
960 
961   Output Parameter:
962 . label - A DMLabel marking all surface points
963 
964   Level: developer
965 
966 .seealso: DMPlexConstructCohesiveCells(), DMPlexLabelComplete()
967 @*/
968 PetscErrorCode DMPlexLabelCohesiveComplete(DM dm, DMLabel label, PetscBool flip, DM subdm)
969 {
970   IS              dimIS, subpointIS;
971   const PetscInt *points, *subpoints;
972   const PetscInt  rev   = flip ? -1 : 1;
973   PetscInt        shift = 100, dim, dep, cStart, cEnd, numPoints, numSubpoints, p, val;
974   PetscErrorCode  ierr;
975 
976   PetscFunctionBegin;
977   ierr = DMPlexGetDimension(dm, &dim);CHKERRQ(ierr);
978   if (subdm) {
979     ierr = DMPlexCreateSubpointIS(subdm, &subpointIS);CHKERRQ(ierr);
980     if (subpointIS) {
981       ierr = ISGetLocalSize(subpointIS, &numSubpoints);CHKERRQ(ierr);
982       ierr = ISGetIndices(subpointIS, &subpoints);CHKERRQ(ierr);
983     }
984   }
985   /* Cell orientation for face gives the side of the fault */
986   ierr = DMLabelGetStratumIS(label, dim-1, &dimIS);CHKERRQ(ierr);
987   if (!dimIS) PetscFunctionReturn(0);
988   ierr = ISGetLocalSize(dimIS, &numPoints);CHKERRQ(ierr);
989   ierr = ISGetIndices(dimIS, &points);CHKERRQ(ierr);
990   for (p = 0; p < numPoints; ++p) {
991     const PetscInt *support;
992     PetscInt        supportSize, s;
993 
994     ierr = DMPlexGetSupportSize(dm, points[p], &supportSize);CHKERRQ(ierr);
995     if (supportSize != 2) SETERRQ2(PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_WRONG, "Split face %d has %d != 2 supports", points[p], supportSize);
996     ierr = DMPlexGetSupport(dm, points[p], &support);CHKERRQ(ierr);
997     for (s = 0; s < supportSize; ++s) {
998       const PetscInt *cone, *ornt;
999       PetscInt        coneSize, c;
1000       PetscBool       pos = PETSC_TRUE;
1001 
1002       ierr = DMPlexGetConeSize(dm, support[s], &coneSize);CHKERRQ(ierr);
1003       ierr = DMPlexGetCone(dm, support[s], &cone);CHKERRQ(ierr);
1004       ierr = DMPlexGetConeOrientation(dm, support[s], &ornt);CHKERRQ(ierr);
1005       for (c = 0; c < coneSize; ++c) {
1006         if (cone[c] == points[p]) {
1007           PetscInt o = ornt[c];
1008 
1009           if (subdm) {
1010             const PetscInt *subcone, *subornt;
1011             PetscInt        subpoint, subface, subconeSize, sc;
1012 
1013             ierr = PetscFindInt(support[s], numSubpoints, subpoints, &subpoint);CHKERRQ(ierr);
1014             ierr = PetscFindInt(points[p],  numSubpoints, subpoints, &subface);CHKERRQ(ierr);
1015             ierr = DMPlexGetConeSize(subdm, subpoint, &subconeSize);CHKERRQ(ierr);
1016             ierr = DMPlexGetCone(subdm, subpoint, &subcone);CHKERRQ(ierr);
1017             ierr = DMPlexGetConeOrientation(subdm, subpoint, &subornt);CHKERRQ(ierr);
1018             for (sc = 0; sc < subconeSize; ++sc) {
1019               if (subcone[sc] == subface) {
1020                 o = subornt[0];
1021                 break;
1022               }
1023             }
1024             if (sc >= subconeSize) SETERRQ2(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Could not find point %d in cone for subpoint %d", points[p], subpoint);
1025           }
1026           if (o >= 0) {
1027             ierr = DMLabelSetValue(label, support[s],  rev*(shift+dim));CHKERRQ(ierr);
1028           } else {
1029             ierr = DMLabelSetValue(label, support[s], -rev*(shift+dim));CHKERRQ(ierr);
1030             pos  = PETSC_FALSE;
1031           }
1032           break;
1033         }
1034       }
1035       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]);
1036       /* Put faces touching the fault in the label */
1037       for (c = 0; c < coneSize; ++c) {
1038         const PetscInt point = cone[c];
1039 
1040         ierr = DMLabelGetValue(label, point, &val);CHKERRQ(ierr);
1041         if (val == -1) {
1042           PetscInt *closure = NULL;
1043           PetscInt  closureSize, cl;
1044 
1045           ierr = DMPlexGetTransitiveClosure(dm, point, PETSC_TRUE, &closureSize, &closure);CHKERRQ(ierr);
1046           for (cl = 0; cl < closureSize*2; cl += 2) {
1047             const PetscInt clp = closure[cl];
1048 
1049             ierr = DMLabelGetValue(label, clp, &val);CHKERRQ(ierr);
1050             if ((val >= 0) && (val < dim-1)) {
1051               ierr = DMLabelSetValue(label, point, pos == PETSC_TRUE ? shift+dim-1 : -(shift+dim-1));CHKERRQ(ierr);
1052               break;
1053             }
1054           }
1055           ierr = DMPlexRestoreTransitiveClosure(dm, point, PETSC_TRUE, &closureSize, &closure);CHKERRQ(ierr);
1056         }
1057       }
1058     }
1059   }
1060   if (subdm) {
1061     if (subpointIS) {ierr = ISRestoreIndices(subpointIS, &subpoints);CHKERRQ(ierr);}
1062     ierr = ISDestroy(&subpointIS);CHKERRQ(ierr);
1063   }
1064   ierr = ISRestoreIndices(dimIS, &points);CHKERRQ(ierr);
1065   ierr = ISDestroy(&dimIS);CHKERRQ(ierr);
1066   /* Search for other cells/faces/edges connected to the fault by a vertex */
1067   ierr = DMPlexGetHeightStratum(dm, 0, &cStart, &cEnd);CHKERRQ(ierr);
1068   ierr = DMLabelGetStratumIS(label, 0, &dimIS);CHKERRQ(ierr);
1069   if (!dimIS) PetscFunctionReturn(0);
1070   ierr = ISGetLocalSize(dimIS, &numPoints);CHKERRQ(ierr);
1071   ierr = ISGetIndices(dimIS, &points);CHKERRQ(ierr);
1072   for (p = 0; p < numPoints; ++p) {
1073     PetscInt *star = NULL;
1074     PetscInt  starSize, s;
1075     PetscInt  again = 1;  /* 0: Finished 1: Keep iterating after a change 2: No change */
1076 
1077     /* First mark cells connected to the fault */
1078     ierr = DMPlexGetTransitiveClosure(dm, points[p], PETSC_FALSE, &starSize, &star);CHKERRQ(ierr);
1079     while (again) {
1080       if (again > 1) SETERRQ(PetscObjectComm((PetscObject)dm), PETSC_ERR_PLIB, "Could not classify all cells connected to the fault");
1081       again = 0;
1082       for (s = 0; s < starSize*2; s += 2) {
1083         const PetscInt  point = star[s];
1084         const PetscInt *cone;
1085         PetscInt        coneSize, c;
1086 
1087         if ((point < cStart) || (point >= cEnd)) continue;
1088         ierr = DMLabelGetValue(label, point, &val);CHKERRQ(ierr);
1089         if (val != -1) continue;
1090         again = 2;
1091         ierr  = DMPlexGetConeSize(dm, point, &coneSize);CHKERRQ(ierr);
1092         ierr  = DMPlexGetCone(dm, point, &cone);CHKERRQ(ierr);
1093         for (c = 0; c < coneSize; ++c) {
1094           ierr = DMLabelGetValue(label, cone[c], &val);CHKERRQ(ierr);
1095           if (val != -1) {
1096             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);
1097             if (val > 0) {
1098               ierr = DMLabelSetValue(label, point,   shift+dim);CHKERRQ(ierr);
1099             } else {
1100               ierr = DMLabelSetValue(label, point, -(shift+dim));CHKERRQ(ierr);
1101             }
1102             again = 1;
1103             break;
1104           }
1105         }
1106       }
1107     }
1108     /* Classify the rest by cell membership */
1109     for (s = 0; s < starSize*2; s += 2) {
1110       const PetscInt point = star[s];
1111 
1112       ierr = DMLabelGetValue(label, point, &val);CHKERRQ(ierr);
1113       if (val == -1) {
1114         PetscInt  *sstar = NULL;
1115         PetscInt   sstarSize, ss;
1116         PetscBool  marked = PETSC_FALSE;
1117 
1118         ierr = DMPlexGetTransitiveClosure(dm, point, PETSC_FALSE, &sstarSize, &sstar);CHKERRQ(ierr);
1119         for (ss = 0; ss < sstarSize*2; ss += 2) {
1120           const PetscInt spoint = sstar[ss];
1121 
1122           if ((spoint < cStart) || (spoint >= cEnd)) continue;
1123           ierr = DMLabelGetValue(label, spoint, &val);CHKERRQ(ierr);
1124           if (val == -1) SETERRQ2(PetscObjectComm((PetscObject)dm), PETSC_ERR_PLIB, "Cell %d in star of %d does not have a valid label", spoint, point);
1125           ierr = DMPlexGetLabelValue(dm, "depth", point, &dep);CHKERRQ(ierr);
1126           if (val > 0) {
1127             ierr = DMLabelSetValue(label, point,   shift+dep);CHKERRQ(ierr);
1128           } else {
1129             ierr = DMLabelSetValue(label, point, -(shift+dep));CHKERRQ(ierr);
1130           }
1131           marked = PETSC_TRUE;
1132           break;
1133         }
1134         ierr = DMPlexRestoreTransitiveClosure(dm, point, PETSC_FALSE, &sstarSize, &sstar);CHKERRQ(ierr);
1135         if (!marked) SETERRQ1(PetscObjectComm((PetscObject)dm), PETSC_ERR_PLIB, "Point %d could not be classified", point);
1136       }
1137     }
1138     ierr = DMPlexRestoreTransitiveClosure(dm, points[p], PETSC_FALSE, &starSize, &star);CHKERRQ(ierr);
1139   }
1140   ierr = ISRestoreIndices(dimIS, &points);CHKERRQ(ierr);
1141   ierr = ISDestroy(&dimIS);CHKERRQ(ierr);
1142   PetscFunctionReturn(0);
1143 }
1144 
1145 #undef __FUNCT__
1146 #define __FUNCT__ "DMPlexMarkSubmesh_Uninterpolated"
1147 /* Here we need the explicit assumption that:
1148 
1149      For any marked cell, the marked vertices constitute a single face
1150 */
1151 static PetscErrorCode DMPlexMarkSubmesh_Uninterpolated(DM dm, DMLabel vertexLabel, PetscInt value, DMLabel subpointMap, PetscInt *numFaces, PetscInt *nFV, DM subdm)
1152 {
1153   IS               subvertexIS;
1154   const PetscInt  *subvertices;
1155   PetscInt        *pStart, *pEnd, *pMax, pSize;
1156   PetscInt         depth, dim, d, numSubVerticesInitial = 0, v;
1157   PetscErrorCode   ierr;
1158 
1159   PetscFunctionBegin;
1160   *numFaces = 0;
1161   *nFV      = 0;
1162   ierr = DMPlexGetDepth(dm, &depth);CHKERRQ(ierr);
1163   ierr = DMPlexGetDimension(dm, &dim);CHKERRQ(ierr);
1164   pSize = PetscMax(depth, dim) + 1;
1165   ierr = PetscMalloc3(pSize,PetscInt,&pStart,pSize,PetscInt,&pEnd,pSize,PetscInt,&pMax);CHKERRQ(ierr);
1166   ierr = DMPlexGetHybridBounds(dm, &pMax[depth], depth>1 ? &pMax[depth-1] : NULL, depth > 2 ? &pMax[1] : NULL, &pMax[0]);CHKERRQ(ierr);
1167   for (d = 0; d <= depth; ++d) {
1168     ierr = DMPlexGetDepthStratum(dm, d, &pStart[d], &pEnd[d]);CHKERRQ(ierr);
1169     if (pMax[d] >= 0) pEnd[d] = PetscMin(pEnd[d], pMax[d]);
1170   }
1171   /* Loop over initial vertices and mark all faces in the collective star() */
1172   ierr = DMLabelGetStratumIS(vertexLabel, value, &subvertexIS);CHKERRQ(ierr);
1173   if (subvertexIS) {
1174     ierr = ISGetSize(subvertexIS, &numSubVerticesInitial);CHKERRQ(ierr);
1175     ierr = ISGetIndices(subvertexIS, &subvertices);CHKERRQ(ierr);
1176   }
1177   for (v = 0; v < numSubVerticesInitial; ++v) {
1178     const PetscInt vertex = subvertices[v];
1179     PetscInt      *star   = NULL;
1180     PetscInt       starSize, s, numCells = 0, c;
1181 
1182     ierr = DMPlexGetTransitiveClosure(dm, vertex, PETSC_FALSE, &starSize, &star);CHKERRQ(ierr);
1183     for (s = 0; s < starSize*2; s += 2) {
1184       const PetscInt point = star[s];
1185       if ((point >= pStart[depth]) && (point < pEnd[depth])) star[numCells++] = point;
1186     }
1187     for (c = 0; c < numCells; ++c) {
1188       const PetscInt cell    = star[c];
1189       PetscInt      *closure = NULL;
1190       PetscInt       closureSize, cl;
1191       PetscInt       cellLoc, numCorners = 0, faceSize = 0;
1192 
1193       ierr = DMLabelGetValue(subpointMap, cell, &cellLoc);CHKERRQ(ierr);
1194       if (cellLoc == 2) continue;
1195       if (cellLoc >= 0) SETERRQ2(PetscObjectComm((PetscObject)dm), PETSC_ERR_PLIB, "Cell %d has dimension %d in the surface label", cell, cellLoc);
1196       ierr = DMPlexGetTransitiveClosure(dm, cell, PETSC_TRUE, &closureSize, &closure);CHKERRQ(ierr);
1197       for (cl = 0; cl < closureSize*2; cl += 2) {
1198         const PetscInt point = closure[cl];
1199         PetscInt       vertexLoc;
1200 
1201         if ((point >= pStart[0]) && (point < pEnd[0])) {
1202           ++numCorners;
1203           ierr = DMLabelGetValue(vertexLabel, point, &vertexLoc);CHKERRQ(ierr);
1204           if (vertexLoc == value) closure[faceSize++] = point;
1205         }
1206       }
1207       if (!(*nFV)) {ierr = DMPlexGetNumFaceVertices(dm, dim, numCorners, nFV);CHKERRQ(ierr);}
1208       if (faceSize > *nFV) SETERRQ1(PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_WRONG, "Invalid submesh: Too many vertices %d of an element on the surface", faceSize);
1209       if (faceSize == *nFV) {
1210         const PetscInt *cells = NULL;
1211         PetscInt        numCells, nc;
1212 
1213         ++(*numFaces);
1214         for (cl = 0; cl < faceSize; ++cl) {
1215           ierr = DMLabelSetValue(subpointMap, closure[cl], 0);CHKERRQ(ierr);
1216         }
1217         ierr = DMPlexGetJoin(dm, faceSize, closure, &numCells, &cells);CHKERRQ(ierr);
1218         for (nc = 0; nc < numCells; ++nc) {
1219           ierr = DMLabelSetValue(subpointMap, cells[nc], 2);CHKERRQ(ierr);
1220         }
1221         ierr = DMPlexRestoreJoin(dm, faceSize, closure, &numCells, &cells);CHKERRQ(ierr);
1222       }
1223       ierr = DMPlexRestoreTransitiveClosure(dm, cell, PETSC_TRUE, &closureSize, &closure);CHKERRQ(ierr);
1224     }
1225     ierr = DMPlexRestoreTransitiveClosure(dm, vertex, PETSC_FALSE, &starSize, &star);CHKERRQ(ierr);
1226   }
1227   if (subvertexIS) {
1228     ierr = ISRestoreIndices(subvertexIS, &subvertices);CHKERRQ(ierr);
1229   }
1230   ierr = ISDestroy(&subvertexIS);CHKERRQ(ierr);
1231   ierr = PetscFree3(pStart,pEnd,pMax);CHKERRQ(ierr);
1232   PetscFunctionReturn(0);
1233 }
1234 
1235 #undef __FUNCT__
1236 #define __FUNCT__ "DMPlexMarkSubmesh_Interpolated"
1237 static PetscErrorCode DMPlexMarkSubmesh_Interpolated(DM dm, DMLabel vertexLabel, PetscInt value, DMLabel subpointMap, DM subdm)
1238 {
1239   IS               subvertexIS;
1240   const PetscInt  *subvertices;
1241   PetscInt        *pStart, *pEnd, *pMax;
1242   PetscInt         dim, d, numSubVerticesInitial = 0, v;
1243   PetscErrorCode   ierr;
1244 
1245   PetscFunctionBegin;
1246   ierr = DMPlexGetDimension(dm, &dim);CHKERRQ(ierr);
1247   ierr = PetscMalloc3(dim+1,PetscInt,&pStart,dim+1,PetscInt,&pEnd,dim+1,PetscInt,&pMax);CHKERRQ(ierr);
1248   ierr = DMPlexGetHybridBounds(dm, &pMax[dim], dim>1 ? &pMax[dim-1] : NULL, dim > 2 ? &pMax[1] : NULL, &pMax[0]);CHKERRQ(ierr);
1249   for (d = 0; d <= dim; ++d) {
1250     ierr = DMPlexGetDepthStratum(dm, d, &pStart[d], &pEnd[d]);CHKERRQ(ierr);
1251     if (pMax[d] >= 0) pEnd[d] = PetscMin(pEnd[d], pMax[d]);
1252   }
1253   /* Loop over initial vertices and mark all faces in the collective star() */
1254   ierr = DMLabelGetStratumIS(vertexLabel, value, &subvertexIS);CHKERRQ(ierr);
1255   if (subvertexIS) {
1256     ierr = ISGetSize(subvertexIS, &numSubVerticesInitial);CHKERRQ(ierr);
1257     ierr = ISGetIndices(subvertexIS, &subvertices);CHKERRQ(ierr);
1258   }
1259   for (v = 0; v < numSubVerticesInitial; ++v) {
1260     const PetscInt vertex = subvertices[v];
1261     PetscInt      *star   = NULL;
1262     PetscInt       starSize, s, numFaces = 0, f;
1263 
1264     ierr = DMPlexGetTransitiveClosure(dm, vertex, PETSC_FALSE, &starSize, &star);CHKERRQ(ierr);
1265     for (s = 0; s < starSize*2; s += 2) {
1266       const PetscInt point = star[s];
1267       if ((point >= pStart[dim-1]) && (point < pEnd[dim-1])) star[numFaces++] = point;
1268     }
1269     for (f = 0; f < numFaces; ++f) {
1270       const PetscInt face    = star[f];
1271       PetscInt      *closure = NULL;
1272       PetscInt       closureSize, c;
1273       PetscInt       faceLoc;
1274 
1275       ierr = DMLabelGetValue(subpointMap, face, &faceLoc);CHKERRQ(ierr);
1276       if (faceLoc == dim-1) continue;
1277       if (faceLoc >= 0) SETERRQ2(PetscObjectComm((PetscObject)dm), PETSC_ERR_PLIB, "Face %d has dimension %d in the surface label", face, faceLoc);
1278       ierr = DMPlexGetTransitiveClosure(dm, face, PETSC_TRUE, &closureSize, &closure);CHKERRQ(ierr);
1279       for (c = 0; c < closureSize*2; c += 2) {
1280         const PetscInt point = closure[c];
1281         PetscInt       vertexLoc;
1282 
1283         if ((point >= pStart[0]) && (point < pEnd[0])) {
1284           ierr = DMLabelGetValue(vertexLabel, point, &vertexLoc);CHKERRQ(ierr);
1285           if (vertexLoc != value) break;
1286         }
1287       }
1288       if (c == closureSize*2) {
1289         const PetscInt *support;
1290         PetscInt        supportSize, s;
1291 
1292         for (c = 0; c < closureSize*2; c += 2) {
1293           const PetscInt point = closure[c];
1294 
1295           for (d = 0; d < dim; ++d) {
1296             if ((point >= pStart[d]) && (point < pEnd[d])) {
1297               ierr = DMLabelSetValue(subpointMap, point, d);CHKERRQ(ierr);
1298               break;
1299             }
1300           }
1301         }
1302         ierr = DMPlexGetSupportSize(dm, face, &supportSize);CHKERRQ(ierr);
1303         ierr = DMPlexGetSupport(dm, face, &support);CHKERRQ(ierr);
1304         for (s = 0; s < supportSize; ++s) {
1305           ierr = DMLabelSetValue(subpointMap, support[s], dim);CHKERRQ(ierr);
1306         }
1307       }
1308       ierr = DMPlexRestoreTransitiveClosure(dm, face, PETSC_TRUE, &closureSize, &closure);CHKERRQ(ierr);
1309     }
1310     ierr = DMPlexRestoreTransitiveClosure(dm, vertex, PETSC_FALSE, &starSize, &star);CHKERRQ(ierr);
1311   }
1312   if (subvertexIS) {
1313     ierr = ISRestoreIndices(subvertexIS, &subvertices);CHKERRQ(ierr);
1314   }
1315   ierr = ISDestroy(&subvertexIS);CHKERRQ(ierr);
1316   ierr = PetscFree3(pStart,pEnd,pMax);CHKERRQ(ierr);
1317   PetscFunctionReturn(0);
1318 }
1319 
1320 #undef __FUNCT__
1321 #define __FUNCT__ "DMPlexMarkCohesiveSubmesh_Uninterpolated"
1322 static PetscErrorCode DMPlexMarkCohesiveSubmesh_Uninterpolated(DM dm, PetscBool hasLagrange, DMLabel subpointMap, PetscInt *numFaces, PetscInt *nFV, PetscInt *subCells[], DM subdm)
1323 {
1324   const PetscInt *cone;
1325   PetscInt        dim, cMax, cEnd, c, p, coneSize;
1326   PetscErrorCode  ierr;
1327 
1328   PetscFunctionBegin;
1329   *numFaces = 0;
1330   *nFV = 0;
1331   ierr = DMPlexGetDimension(dm, &dim);CHKERRQ(ierr);
1332   ierr = DMPlexGetHeightStratum(dm, 0, NULL, &cEnd);CHKERRQ(ierr);
1333   ierr = DMPlexGetHybridBounds(dm, &cMax, NULL, NULL, NULL);CHKERRQ(ierr);
1334   if (cMax < 0) PetscFunctionReturn(0);
1335   ierr = DMPlexGetConeSize(dm, cMax, &coneSize);CHKERRQ(ierr);
1336   *numFaces = cEnd - cMax;
1337   *nFV      = hasLagrange ? coneSize/3 : coneSize/2;
1338   ierr = PetscMalloc(*numFaces *2 * sizeof(PetscInt), subCells);CHKERRQ(ierr);
1339   for (c = cMax; c < cEnd; ++c) {
1340     const PetscInt *cells;
1341     PetscInt        numCells;
1342 
1343     ierr = DMPlexGetCone(dm, c, &cone);CHKERRQ(ierr);
1344     for (p = 0; p < *nFV; ++p) {
1345       ierr = DMLabelSetValue(subpointMap, cone[p], 0);CHKERRQ(ierr);
1346     }
1347     /* Negative face */
1348     ierr = DMPlexGetJoin(dm, *nFV, cone, &numCells, &cells);CHKERRQ(ierr);
1349     if (numCells != 2) SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Cohesive cells should separate two cells");
1350     for (p = 0; p < numCells; ++p) {
1351       ierr = DMLabelSetValue(subpointMap, cells[p], 2);CHKERRQ(ierr);
1352       (*subCells)[(c-cMax)*2+p] = cells[p];
1353     }
1354     ierr = DMPlexRestoreJoin(dm, *nFV, cone, &numCells, &cells);CHKERRQ(ierr);
1355     /* Positive face is not included */
1356   }
1357   PetscFunctionReturn(0);
1358 }
1359 
1360 #undef __FUNCT__
1361 #define __FUNCT__ "DMPlexMarkCohesiveSubmesh_Interpolated"
1362 static PetscErrorCode DMPlexMarkCohesiveSubmesh_Interpolated(DM dm, PetscBool hasLagrange, DMLabel subpointMap, DM subdm)
1363 {
1364   PetscInt      *pStart, *pEnd;
1365   PetscInt       dim, cMax, cEnd, c, d;
1366   PetscErrorCode ierr;
1367 
1368   PetscFunctionBegin;
1369   ierr = DMPlexGetDimension(dm, &dim);CHKERRQ(ierr);
1370   ierr = DMPlexGetHeightStratum(dm, 0, NULL, &cEnd);CHKERRQ(ierr);
1371   ierr = DMPlexGetHybridBounds(dm, &cMax, NULL, NULL, NULL);CHKERRQ(ierr);
1372   if (cMax < 0) PetscFunctionReturn(0);
1373   ierr = PetscMalloc2(dim+1,PetscInt,&pStart,dim+1,PetscInt,&pEnd);CHKERRQ(ierr);
1374   for (d = 0; d <= dim; ++d) {
1375     ierr = DMPlexGetDepthStratum(dm, d, &pStart[d], &pEnd[d]);CHKERRQ(ierr);
1376   }
1377   for (c = cMax; c < cEnd; ++c) {
1378     const PetscInt *cone;
1379     PetscInt       *closure = NULL;
1380     PetscInt        coneSize, closureSize, cl;
1381 
1382     ierr = DMPlexGetConeSize(dm, c, &coneSize);CHKERRQ(ierr);
1383     if (hasLagrange) {
1384       if (coneSize != 3) SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Cohesive cells should separate two cells");
1385     } else {
1386       if (coneSize != 2) SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Cohesive cells should separate two cells");
1387     }
1388     /* Negative face */
1389     ierr = DMPlexGetCone(dm, c, &cone);CHKERRQ(ierr);
1390     ierr = DMPlexGetTransitiveClosure(dm, cone[0], PETSC_TRUE, &closureSize, &closure);CHKERRQ(ierr);
1391     for (cl = 0; cl < closureSize*2; cl += 2) {
1392       const PetscInt point = closure[cl];
1393 
1394       for (d = 0; d <= dim; ++d) {
1395         if ((point >= pStart[d]) && (point < pEnd[d])) {
1396           ierr = DMLabelSetValue(subpointMap, point, d);CHKERRQ(ierr);
1397           break;
1398         }
1399       }
1400     }
1401     ierr = DMPlexRestoreTransitiveClosure(dm, cone[0], PETSC_TRUE, &closureSize, &closure);CHKERRQ(ierr);
1402     /* Cells -- positive face is not included */
1403     for (cl = 0; cl < 1; ++cl) {
1404       const PetscInt *support;
1405       PetscInt        supportSize, s;
1406 
1407       ierr = DMPlexGetSupportSize(dm, cone[cl], &supportSize);CHKERRQ(ierr);
1408       if (supportSize != 2) SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Cohesive faces should separate two cells");
1409       ierr = DMPlexGetSupport(dm, cone[cl], &support);CHKERRQ(ierr);
1410       for (s = 0; s < supportSize; ++s) {
1411         ierr = DMLabelSetValue(subpointMap, support[s], dim);CHKERRQ(ierr);
1412       }
1413     }
1414   }
1415   ierr = PetscFree2(pStart, pEnd);CHKERRQ(ierr);
1416   PetscFunctionReturn(0);
1417 }
1418 
1419 #undef __FUNCT__
1420 #define __FUNCT__ "DMPlexGetFaceOrientation"
1421 PetscErrorCode DMPlexGetFaceOrientation(DM dm, PetscInt cell, PetscInt numCorners, PetscInt indices[], PetscInt oppositeVertex, PetscInt origVertices[], PetscInt faceVertices[], PetscBool *posOriented)
1422 {
1423   MPI_Comm       comm;
1424   PetscBool      posOrient = PETSC_FALSE;
1425   const PetscInt debug     = 0;
1426   PetscInt       cellDim, faceSize, f;
1427   PetscErrorCode ierr;
1428 
1429   PetscFunctionBegin;
1430   ierr = PetscObjectGetComm((PetscObject)dm,&comm);CHKERRQ(ierr);
1431   ierr = DMPlexGetDimension(dm, &cellDim);CHKERRQ(ierr);
1432   if (debug) {PetscPrintf(comm, "cellDim: %d numCorners: %d\n", cellDim, numCorners);CHKERRQ(ierr);}
1433 
1434   if (cellDim == numCorners-1) {
1435     /* Simplices */
1436     faceSize  = numCorners-1;
1437     posOrient = !(oppositeVertex%2) ? PETSC_TRUE : PETSC_FALSE;
1438   } else if (cellDim == 1 && numCorners == 3) {
1439     /* Quadratic line */
1440     faceSize  = 1;
1441     posOrient = PETSC_TRUE;
1442   } else if (cellDim == 2 && numCorners == 4) {
1443     /* Quads */
1444     faceSize = 2;
1445     if ((indices[1] > indices[0]) && (indices[1] - indices[0] == 1)) {
1446       posOrient = PETSC_TRUE;
1447     } else if ((indices[0] == 3) && (indices[1] == 0)) {
1448       posOrient = PETSC_TRUE;
1449     } else {
1450       if (((indices[0] > indices[1]) && (indices[0] - indices[1] == 1)) || ((indices[0] == 0) && (indices[1] == 3))) {
1451         posOrient = PETSC_FALSE;
1452       } else SETERRQ(comm, PETSC_ERR_ARG_WRONG, "Invalid quad crossedge");
1453     }
1454   } else if (cellDim == 2 && numCorners == 6) {
1455     /* Quadratic triangle (I hate this) */
1456     /* Edges are determined by the first 2 vertices (corners of edges) */
1457     const PetscInt faceSizeTri = 3;
1458     PetscInt       sortedIndices[3], i, iFace;
1459     PetscBool      found                    = PETSC_FALSE;
1460     PetscInt       faceVerticesTriSorted[9] = {
1461       0, 3,  4, /* bottom */
1462       1, 4,  5, /* right */
1463       2, 3,  5, /* left */
1464     };
1465     PetscInt       faceVerticesTri[9] = {
1466       0, 3,  4, /* bottom */
1467       1, 4,  5, /* right */
1468       2, 5,  3, /* left */
1469     };
1470 
1471     faceSize = faceSizeTri;
1472     for (i = 0; i < faceSizeTri; ++i) sortedIndices[i] = indices[i];
1473     ierr = PetscSortInt(faceSizeTri, sortedIndices);CHKERRQ(ierr);
1474     for (iFace = 0; iFace < 3; ++iFace) {
1475       const PetscInt ii = iFace*faceSizeTri;
1476       PetscInt       fVertex, cVertex;
1477 
1478       if ((sortedIndices[0] == faceVerticesTriSorted[ii+0]) &&
1479           (sortedIndices[1] == faceVerticesTriSorted[ii+1])) {
1480         for (fVertex = 0; fVertex < faceSizeTri; ++fVertex) {
1481           for (cVertex = 0; cVertex < faceSizeTri; ++cVertex) {
1482             if (indices[cVertex] == faceVerticesTri[ii+fVertex]) {
1483               faceVertices[fVertex] = origVertices[cVertex];
1484               break;
1485             }
1486           }
1487         }
1488         found = PETSC_TRUE;
1489         break;
1490       }
1491     }
1492     if (!found) SETERRQ(comm, PETSC_ERR_ARG_WRONG, "Invalid tri crossface");
1493     if (posOriented) *posOriented = PETSC_TRUE;
1494     PetscFunctionReturn(0);
1495   } else if (cellDim == 2 && numCorners == 9) {
1496     /* Quadratic quad (I hate this) */
1497     /* Edges are determined by the first 2 vertices (corners of edges) */
1498     const PetscInt faceSizeQuad = 3;
1499     PetscInt       sortedIndices[3], i, iFace;
1500     PetscBool      found                      = PETSC_FALSE;
1501     PetscInt       faceVerticesQuadSorted[12] = {
1502       0, 1,  4, /* bottom */
1503       1, 2,  5, /* right */
1504       2, 3,  6, /* top */
1505       0, 3,  7, /* left */
1506     };
1507     PetscInt       faceVerticesQuad[12] = {
1508       0, 1,  4, /* bottom */
1509       1, 2,  5, /* right */
1510       2, 3,  6, /* top */
1511       3, 0,  7, /* left */
1512     };
1513 
1514     faceSize = faceSizeQuad;
1515     for (i = 0; i < faceSizeQuad; ++i) sortedIndices[i] = indices[i];
1516     ierr = PetscSortInt(faceSizeQuad, sortedIndices);CHKERRQ(ierr);
1517     for (iFace = 0; iFace < 4; ++iFace) {
1518       const PetscInt ii = iFace*faceSizeQuad;
1519       PetscInt       fVertex, cVertex;
1520 
1521       if ((sortedIndices[0] == faceVerticesQuadSorted[ii+0]) &&
1522           (sortedIndices[1] == faceVerticesQuadSorted[ii+1])) {
1523         for (fVertex = 0; fVertex < faceSizeQuad; ++fVertex) {
1524           for (cVertex = 0; cVertex < faceSizeQuad; ++cVertex) {
1525             if (indices[cVertex] == faceVerticesQuad[ii+fVertex]) {
1526               faceVertices[fVertex] = origVertices[cVertex];
1527               break;
1528             }
1529           }
1530         }
1531         found = PETSC_TRUE;
1532         break;
1533       }
1534     }
1535     if (!found) SETERRQ(comm, PETSC_ERR_ARG_WRONG, "Invalid quad crossface");
1536     if (posOriented) *posOriented = PETSC_TRUE;
1537     PetscFunctionReturn(0);
1538   } else if (cellDim == 3 && numCorners == 8) {
1539     /* Hexes
1540        A hex is two oriented quads with the normal of the first
1541        pointing up at the second.
1542 
1543           7---6
1544          /|  /|
1545         4---5 |
1546         | 3-|-2
1547         |/  |/
1548         0---1
1549 
1550         Faces are determined by the first 4 vertices (corners of faces) */
1551     const PetscInt faceSizeHex = 4;
1552     PetscInt       sortedIndices[4], i, iFace;
1553     PetscBool      found                     = PETSC_FALSE;
1554     PetscInt       faceVerticesHexSorted[24] = {
1555       0, 1, 2, 3,  /* bottom */
1556       4, 5, 6, 7,  /* top */
1557       0, 1, 4, 5,  /* front */
1558       1, 2, 5, 6,  /* right */
1559       2, 3, 6, 7,  /* back */
1560       0, 3, 4, 7,  /* left */
1561     };
1562     PetscInt       faceVerticesHex[24] = {
1563       3, 2, 1, 0,  /* bottom */
1564       4, 5, 6, 7,  /* top */
1565       0, 1, 5, 4,  /* front */
1566       1, 2, 6, 5,  /* right */
1567       2, 3, 7, 6,  /* back */
1568       3, 0, 4, 7,  /* left */
1569     };
1570 
1571     faceSize = faceSizeHex;
1572     for (i = 0; i < faceSizeHex; ++i) sortedIndices[i] = indices[i];
1573     ierr = PetscSortInt(faceSizeHex, sortedIndices);CHKERRQ(ierr);
1574     for (iFace = 0; iFace < 6; ++iFace) {
1575       const PetscInt ii = iFace*faceSizeHex;
1576       PetscInt       fVertex, cVertex;
1577 
1578       if ((sortedIndices[0] == faceVerticesHexSorted[ii+0]) &&
1579           (sortedIndices[1] == faceVerticesHexSorted[ii+1]) &&
1580           (sortedIndices[2] == faceVerticesHexSorted[ii+2]) &&
1581           (sortedIndices[3] == faceVerticesHexSorted[ii+3])) {
1582         for (fVertex = 0; fVertex < faceSizeHex; ++fVertex) {
1583           for (cVertex = 0; cVertex < faceSizeHex; ++cVertex) {
1584             if (indices[cVertex] == faceVerticesHex[ii+fVertex]) {
1585               faceVertices[fVertex] = origVertices[cVertex];
1586               break;
1587             }
1588           }
1589         }
1590         found = PETSC_TRUE;
1591         break;
1592       }
1593     }
1594     if (!found) SETERRQ(comm, PETSC_ERR_ARG_WRONG, "Invalid hex crossface");
1595     if (posOriented) *posOriented = PETSC_TRUE;
1596     PetscFunctionReturn(0);
1597   } else if (cellDim == 3 && numCorners == 10) {
1598     /* Quadratic tet */
1599     /* Faces are determined by the first 3 vertices (corners of faces) */
1600     const PetscInt faceSizeTet = 6;
1601     PetscInt       sortedIndices[6], i, iFace;
1602     PetscBool      found                     = PETSC_FALSE;
1603     PetscInt       faceVerticesTetSorted[24] = {
1604       0, 1, 2,  6, 7, 8, /* bottom */
1605       0, 3, 4,  6, 7, 9,  /* front */
1606       1, 4, 5,  7, 8, 9,  /* right */
1607       2, 3, 5,  6, 8, 9,  /* left */
1608     };
1609     PetscInt       faceVerticesTet[24] = {
1610       0, 1, 2,  6, 7, 8, /* bottom */
1611       0, 4, 3,  6, 7, 9,  /* front */
1612       1, 5, 4,  7, 8, 9,  /* right */
1613       2, 3, 5,  8, 6, 9,  /* left */
1614     };
1615 
1616     faceSize = faceSizeTet;
1617     for (i = 0; i < faceSizeTet; ++i) sortedIndices[i] = indices[i];
1618     ierr = PetscSortInt(faceSizeTet, sortedIndices);CHKERRQ(ierr);
1619     for (iFace=0; iFace < 4; ++iFace) {
1620       const PetscInt ii = iFace*faceSizeTet;
1621       PetscInt       fVertex, cVertex;
1622 
1623       if ((sortedIndices[0] == faceVerticesTetSorted[ii+0]) &&
1624           (sortedIndices[1] == faceVerticesTetSorted[ii+1]) &&
1625           (sortedIndices[2] == faceVerticesTetSorted[ii+2]) &&
1626           (sortedIndices[3] == faceVerticesTetSorted[ii+3])) {
1627         for (fVertex = 0; fVertex < faceSizeTet; ++fVertex) {
1628           for (cVertex = 0; cVertex < faceSizeTet; ++cVertex) {
1629             if (indices[cVertex] == faceVerticesTet[ii+fVertex]) {
1630               faceVertices[fVertex] = origVertices[cVertex];
1631               break;
1632             }
1633           }
1634         }
1635         found = PETSC_TRUE;
1636         break;
1637       }
1638     }
1639     if (!found) SETERRQ(comm, PETSC_ERR_ARG_WRONG, "Invalid tet crossface");
1640     if (posOriented) *posOriented = PETSC_TRUE;
1641     PetscFunctionReturn(0);
1642   } else if (cellDim == 3 && numCorners == 27) {
1643     /* Quadratic hexes (I hate this)
1644        A hex is two oriented quads with the normal of the first
1645        pointing up at the second.
1646 
1647          7---6
1648         /|  /|
1649        4---5 |
1650        | 3-|-2
1651        |/  |/
1652        0---1
1653 
1654        Faces are determined by the first 4 vertices (corners of faces) */
1655     const PetscInt faceSizeQuadHex = 9;
1656     PetscInt       sortedIndices[9], i, iFace;
1657     PetscBool      found                         = PETSC_FALSE;
1658     PetscInt       faceVerticesQuadHexSorted[54] = {
1659       0, 1, 2, 3,  8, 9, 10, 11,  24, /* bottom */
1660       4, 5, 6, 7,  12, 13, 14, 15,  25, /* top */
1661       0, 1, 4, 5,  8, 12, 16, 17,  22, /* front */
1662       1, 2, 5, 6,  9, 13, 17, 18,  21, /* right */
1663       2, 3, 6, 7,  10, 14, 18, 19,  23, /* back */
1664       0, 3, 4, 7,  11, 15, 16, 19,  20, /* left */
1665     };
1666     PetscInt       faceVerticesQuadHex[54] = {
1667       3, 2, 1, 0,  10, 9, 8, 11,  24, /* bottom */
1668       4, 5, 6, 7,  12, 13, 14, 15,  25, /* top */
1669       0, 1, 5, 4,  8, 17, 12, 16,  22, /* front */
1670       1, 2, 6, 5,  9, 18, 13, 17,  21, /* right */
1671       2, 3, 7, 6,  10, 19, 14, 18,  23, /* back */
1672       3, 0, 4, 7,  11, 16, 15, 19,  20 /* left */
1673     };
1674 
1675     faceSize = faceSizeQuadHex;
1676     for (i = 0; i < faceSizeQuadHex; ++i) sortedIndices[i] = indices[i];
1677     ierr = PetscSortInt(faceSizeQuadHex, sortedIndices);CHKERRQ(ierr);
1678     for (iFace = 0; iFace < 6; ++iFace) {
1679       const PetscInt ii = iFace*faceSizeQuadHex;
1680       PetscInt       fVertex, cVertex;
1681 
1682       if ((sortedIndices[0] == faceVerticesQuadHexSorted[ii+0]) &&
1683           (sortedIndices[1] == faceVerticesQuadHexSorted[ii+1]) &&
1684           (sortedIndices[2] == faceVerticesQuadHexSorted[ii+2]) &&
1685           (sortedIndices[3] == faceVerticesQuadHexSorted[ii+3])) {
1686         for (fVertex = 0; fVertex < faceSizeQuadHex; ++fVertex) {
1687           for (cVertex = 0; cVertex < faceSizeQuadHex; ++cVertex) {
1688             if (indices[cVertex] == faceVerticesQuadHex[ii+fVertex]) {
1689               faceVertices[fVertex] = origVertices[cVertex];
1690               break;
1691             }
1692           }
1693         }
1694         found = PETSC_TRUE;
1695         break;
1696       }
1697     }
1698     if (!found) SETERRQ(comm, PETSC_ERR_ARG_WRONG, "Invalid hex crossface");
1699     if (posOriented) *posOriented = PETSC_TRUE;
1700     PetscFunctionReturn(0);
1701   } else SETERRQ(comm, PETSC_ERR_ARG_WRONG, "Unknown cell type for faceOrientation().");
1702   if (!posOrient) {
1703     if (debug) {ierr = PetscPrintf(comm, "  Reversing initial face orientation\n");CHKERRQ(ierr);}
1704     for (f = 0; f < faceSize; ++f) faceVertices[f] = origVertices[faceSize-1 - f];
1705   } else {
1706     if (debug) {ierr = PetscPrintf(comm, "  Keeping initial face orientation\n");CHKERRQ(ierr);}
1707     for (f = 0; f < faceSize; ++f) faceVertices[f] = origVertices[f];
1708   }
1709   if (posOriented) *posOriented = posOrient;
1710   PetscFunctionReturn(0);
1711 }
1712 
1713 #undef __FUNCT__
1714 #define __FUNCT__ "DMPlexGetOrientedFace"
1715 /*
1716     Given a cell and a face, as a set of vertices,
1717       return the oriented face, as a set of vertices, in faceVertices
1718     The orientation is such that the face normal points out of the cell
1719 */
1720 PetscErrorCode DMPlexGetOrientedFace(DM dm, PetscInt cell, PetscInt faceSize, const PetscInt face[], PetscInt numCorners, PetscInt indices[], PetscInt origVertices[], PetscInt faceVertices[], PetscBool *posOriented)
1721 {
1722   const PetscInt *cone = NULL;
1723   PetscInt        coneSize, v, f, v2;
1724   PetscInt        oppositeVertex = -1;
1725   PetscErrorCode  ierr;
1726 
1727   PetscFunctionBegin;
1728   ierr = DMPlexGetConeSize(dm, cell, &coneSize);CHKERRQ(ierr);
1729   ierr = DMPlexGetCone(dm, cell, &cone);CHKERRQ(ierr);
1730   for (v = 0, v2 = 0; v < coneSize; ++v) {
1731     PetscBool found = PETSC_FALSE;
1732 
1733     for (f = 0; f < faceSize; ++f) {
1734       if (face[f] == cone[v]) {
1735         found = PETSC_TRUE; break;
1736       }
1737     }
1738     if (found) {
1739       indices[v2]      = v;
1740       origVertices[v2] = cone[v];
1741       ++v2;
1742     } else {
1743       oppositeVertex = v;
1744     }
1745   }
1746   ierr = DMPlexGetFaceOrientation(dm, cell, numCorners, indices, oppositeVertex, origVertices, faceVertices, posOriented);CHKERRQ(ierr);
1747   PetscFunctionReturn(0);
1748 }
1749 
1750 #undef __FUNCT__
1751 #define __FUNCT__ "DMPlexInsertFace_Internal"
1752 /*
1753   DMPlexInsertFace_Internal - Puts a face into the mesh
1754 
1755   Not collective
1756 
1757   Input Parameters:
1758   + dm              - The DMPlex
1759   . numFaceVertex   - The number of vertices in the face
1760   . faceVertices    - The vertices in the face for dm
1761   . subfaceVertices - The vertices in the face for subdm
1762   . numCorners      - The number of vertices in the cell
1763   . cell            - A cell in dm containing the face
1764   . subcell         - A cell in subdm containing the face
1765   . firstFace       - First face in the mesh
1766   - newFacePoint    - Next face in the mesh
1767 
1768   Output Parameters:
1769   . newFacePoint - Contains next face point number on input, updated on output
1770 
1771   Level: developer
1772 */
1773 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)
1774 {
1775   MPI_Comm        comm;
1776   DM_Plex        *submesh = (DM_Plex*) subdm->data;
1777   const PetscInt *faces;
1778   PetscInt        numFaces, coneSize;
1779   PetscErrorCode  ierr;
1780 
1781   PetscFunctionBegin;
1782   ierr = PetscObjectGetComm((PetscObject)dm,&comm);CHKERRQ(ierr);
1783   ierr = DMPlexGetConeSize(subdm, subcell, &coneSize);CHKERRQ(ierr);
1784   if (coneSize != 1) SETERRQ2(comm, PETSC_ERR_ARG_OUTOFRANGE, "Cone size of cell %d is %d != 1", cell, coneSize);
1785 #if 0
1786   /* Cannot use this because support() has not been constructed yet */
1787   ierr = DMPlexGetJoin(subdm, numFaceVertices, subfaceVertices, &numFaces, &faces);CHKERRQ(ierr);
1788 #else
1789   {
1790     PetscInt f;
1791 
1792     numFaces = 0;
1793     ierr     = DMGetWorkArray(subdm, 1, PETSC_INT, (void **) &faces);CHKERRQ(ierr);
1794     for (f = firstFace; f < *newFacePoint; ++f) {
1795       PetscInt dof, off, d;
1796 
1797       ierr = PetscSectionGetDof(submesh->coneSection, f, &dof);CHKERRQ(ierr);
1798       ierr = PetscSectionGetOffset(submesh->coneSection, f, &off);CHKERRQ(ierr);
1799       /* Yes, I know this is quadratic, but I expect the sizes to be <5 */
1800       for (d = 0; d < dof; ++d) {
1801         const PetscInt p = submesh->cones[off+d];
1802         PetscInt       v;
1803 
1804         for (v = 0; v < numFaceVertices; ++v) {
1805           if (subfaceVertices[v] == p) break;
1806         }
1807         if (v == numFaceVertices) break;
1808       }
1809       if (d == dof) {
1810         numFaces               = 1;
1811         ((PetscInt*) faces)[0] = f;
1812       }
1813     }
1814   }
1815 #endif
1816   if (numFaces > 1) SETERRQ1(comm, PETSC_ERR_ARG_WRONG, "Vertex set had %d faces, not one", numFaces);
1817   else if (numFaces == 1) {
1818     /* Add the other cell neighbor for this face */
1819     ierr = DMPlexSetCone(subdm, subcell, faces);CHKERRQ(ierr);
1820   } else {
1821     PetscInt *indices, *origVertices, *orientedVertices, *orientedSubVertices, v, ov;
1822     PetscBool posOriented;
1823 
1824     ierr                = DMGetWorkArray(subdm, 4*numFaceVertices * sizeof(PetscInt), PETSC_INT, &orientedVertices);CHKERRQ(ierr);
1825     origVertices        = &orientedVertices[numFaceVertices];
1826     indices             = &orientedVertices[numFaceVertices*2];
1827     orientedSubVertices = &orientedVertices[numFaceVertices*3];
1828     ierr                = DMPlexGetOrientedFace(dm, cell, numFaceVertices, faceVertices, numCorners, indices, origVertices, orientedVertices, &posOriented);CHKERRQ(ierr);
1829     /* TODO: I know that routine should return a permutation, not the indices */
1830     for (v = 0; v < numFaceVertices; ++v) {
1831       const PetscInt vertex = faceVertices[v], subvertex = subfaceVertices[v];
1832       for (ov = 0; ov < numFaceVertices; ++ov) {
1833         if (orientedVertices[ov] == vertex) {
1834           orientedSubVertices[ov] = subvertex;
1835           break;
1836         }
1837       }
1838       if (ov == numFaceVertices) SETERRQ1(comm, PETSC_ERR_PLIB, "Could not find face vertex %d in orientated set", vertex);
1839     }
1840     ierr = DMPlexSetCone(subdm, *newFacePoint, orientedSubVertices);CHKERRQ(ierr);
1841     ierr = DMPlexSetCone(subdm, subcell, newFacePoint);CHKERRQ(ierr);
1842     ierr = DMRestoreWorkArray(subdm, 4*numFaceVertices * sizeof(PetscInt), PETSC_INT, &orientedVertices);CHKERRQ(ierr);
1843     ++(*newFacePoint);
1844   }
1845 #if 0
1846   ierr = DMPlexRestoreJoin(subdm, numFaceVertices, subfaceVertices, &numFaces, &faces);CHKERRQ(ierr);
1847 #else
1848   ierr = DMRestoreWorkArray(subdm, 1, PETSC_INT, (void **) &faces);CHKERRQ(ierr);
1849 #endif
1850   PetscFunctionReturn(0);
1851 }
1852 
1853 #undef __FUNCT__
1854 #define __FUNCT__ "DMPlexCreateSubmesh_Uninterpolated"
1855 static PetscErrorCode DMPlexCreateSubmesh_Uninterpolated(DM dm, const char vertexLabelName[], PetscInt value, DM subdm)
1856 {
1857   MPI_Comm        comm;
1858   DMLabel         vertexLabel, subpointMap;
1859   IS              subvertexIS,  subcellIS;
1860   const PetscInt *subVertices, *subCells;
1861   PetscInt        numSubVertices, firstSubVertex, numSubCells;
1862   PetscInt       *subface, maxConeSize, numSubFaces, firstSubFace, newFacePoint, nFV;
1863   PetscInt        vStart, vEnd, c, f;
1864   PetscErrorCode  ierr;
1865 
1866   PetscFunctionBegin;
1867   ierr = PetscObjectGetComm((PetscObject)dm,&comm);CHKERRQ(ierr);
1868   /* Create subpointMap which marks the submesh */
1869   ierr = DMLabelCreate("subpoint_map", &subpointMap);CHKERRQ(ierr);
1870   ierr = DMPlexSetSubpointMap(subdm, subpointMap);CHKERRQ(ierr);
1871   ierr = DMLabelDestroy(&subpointMap);CHKERRQ(ierr);
1872   ierr = DMPlexGetLabel(dm, vertexLabelName, &vertexLabel);CHKERRQ(ierr);
1873   ierr = DMPlexMarkSubmesh_Uninterpolated(dm, vertexLabel, value, subpointMap, &numSubFaces, &nFV, subdm);CHKERRQ(ierr);
1874   /* Setup chart */
1875   ierr = DMLabelGetStratumSize(subpointMap, 0, &numSubVertices);CHKERRQ(ierr);
1876   ierr = DMLabelGetStratumSize(subpointMap, 2, &numSubCells);CHKERRQ(ierr);
1877   ierr = DMPlexSetChart(subdm, 0, numSubCells+numSubFaces+numSubVertices);CHKERRQ(ierr);
1878   ierr = DMPlexSetVTKCellHeight(subdm, 1);CHKERRQ(ierr);
1879   /* Set cone sizes */
1880   firstSubVertex = numSubCells;
1881   firstSubFace   = numSubCells+numSubVertices;
1882   newFacePoint   = firstSubFace;
1883   ierr = DMLabelGetStratumIS(subpointMap, 0, &subvertexIS);CHKERRQ(ierr);
1884   if (subvertexIS) {ierr = ISGetIndices(subvertexIS, &subVertices);CHKERRQ(ierr);}
1885   ierr = DMLabelGetStratumIS(subpointMap, 2, &subcellIS);CHKERRQ(ierr);
1886   if (subcellIS) {ierr = ISGetIndices(subcellIS, &subCells);CHKERRQ(ierr);}
1887   for (c = 0; c < numSubCells; ++c) {
1888     ierr = DMPlexSetConeSize(subdm, c, 1);CHKERRQ(ierr);
1889   }
1890   for (f = firstSubFace; f < firstSubFace+numSubFaces; ++f) {
1891     ierr = DMPlexSetConeSize(subdm, f, nFV);CHKERRQ(ierr);
1892   }
1893   ierr = DMSetUp(subdm);CHKERRQ(ierr);
1894   /* Create face cones */
1895   ierr = DMPlexGetDepthStratum(dm, 0, &vStart, &vEnd);CHKERRQ(ierr);
1896   ierr = DMPlexGetMaxSizes(dm, &maxConeSize, NULL);CHKERRQ(ierr);
1897   ierr = DMGetWorkArray(subdm, maxConeSize, PETSC_INT, (void**) &subface);CHKERRQ(ierr);
1898   for (c = 0; c < numSubCells; ++c) {
1899     const PetscInt cell    = subCells[c];
1900     const PetscInt subcell = c;
1901     PetscInt      *closure = NULL;
1902     PetscInt       closureSize, cl, numCorners = 0, faceSize = 0;
1903 
1904     ierr = DMPlexGetTransitiveClosure(dm, cell, PETSC_TRUE, &closureSize, &closure);CHKERRQ(ierr);
1905     for (cl = 0; cl < closureSize*2; cl += 2) {
1906       const PetscInt point = closure[cl];
1907       PetscInt       subVertex;
1908 
1909       if ((point >= vStart) && (point < vEnd)) {
1910         ++numCorners;
1911         ierr = PetscFindInt(point, numSubVertices, subVertices, &subVertex);CHKERRQ(ierr);
1912         if (subVertex >= 0) {
1913           closure[faceSize] = point;
1914           subface[faceSize] = firstSubVertex+subVertex;
1915           ++faceSize;
1916         }
1917       }
1918     }
1919     if (faceSize > nFV) SETERRQ1(comm, PETSC_ERR_ARG_WRONG, "Invalid submesh: Too many vertices %d of an element on the surface", faceSize);
1920     if (faceSize == nFV) {
1921       ierr = DMPlexInsertFace_Internal(dm, subdm, faceSize, closure, subface, numCorners, cell, subcell, firstSubFace, &newFacePoint);CHKERRQ(ierr);
1922     }
1923     ierr = DMPlexRestoreTransitiveClosure(dm, cell, PETSC_TRUE, &closureSize, &closure);CHKERRQ(ierr);
1924   }
1925   ierr = DMRestoreWorkArray(subdm, maxConeSize, PETSC_INT, (void**) &subface);CHKERRQ(ierr);
1926   ierr = DMPlexSymmetrize(subdm);CHKERRQ(ierr);
1927   ierr = DMPlexStratify(subdm);CHKERRQ(ierr);
1928   /* Build coordinates */
1929   {
1930     PetscSection coordSection, subCoordSection;
1931     Vec          coordinates, subCoordinates;
1932     PetscScalar *coords, *subCoords;
1933     PetscInt     numComp, coordSize, v;
1934 
1935     ierr = DMPlexGetCoordinateSection(dm, &coordSection);CHKERRQ(ierr);
1936     ierr = DMGetCoordinatesLocal(dm, &coordinates);CHKERRQ(ierr);
1937     ierr = DMPlexGetCoordinateSection(subdm, &subCoordSection);CHKERRQ(ierr);
1938     ierr = PetscSectionSetNumFields(subCoordSection, 1);CHKERRQ(ierr);
1939     ierr = PetscSectionGetFieldComponents(coordSection, 0, &numComp);CHKERRQ(ierr);
1940     ierr = PetscSectionSetFieldComponents(subCoordSection, 0, numComp);CHKERRQ(ierr);
1941     ierr = PetscSectionSetChart(subCoordSection, firstSubVertex, firstSubVertex+numSubVertices);CHKERRQ(ierr);
1942     for (v = 0; v < numSubVertices; ++v) {
1943       const PetscInt vertex    = subVertices[v];
1944       const PetscInt subvertex = firstSubVertex+v;
1945       PetscInt       dof;
1946 
1947       ierr = PetscSectionGetDof(coordSection, vertex, &dof);CHKERRQ(ierr);
1948       ierr = PetscSectionSetDof(subCoordSection, subvertex, dof);CHKERRQ(ierr);
1949       ierr = PetscSectionSetFieldDof(subCoordSection, subvertex, 0, dof);CHKERRQ(ierr);
1950     }
1951     ierr = PetscSectionSetUp(subCoordSection);CHKERRQ(ierr);
1952     ierr = PetscSectionGetStorageSize(subCoordSection, &coordSize);CHKERRQ(ierr);
1953     ierr = VecCreate(comm, &subCoordinates);CHKERRQ(ierr);
1954     ierr = VecSetSizes(subCoordinates, coordSize, PETSC_DETERMINE);CHKERRQ(ierr);
1955     ierr = VecSetFromOptions(subCoordinates);CHKERRQ(ierr);
1956     if (coordSize) {
1957       ierr = VecGetArray(coordinates,    &coords);CHKERRQ(ierr);
1958       ierr = VecGetArray(subCoordinates, &subCoords);CHKERRQ(ierr);
1959       for (v = 0; v < numSubVertices; ++v) {
1960         const PetscInt vertex    = subVertices[v];
1961         const PetscInt subvertex = firstSubVertex+v;
1962         PetscInt       dof, off, sdof, soff, d;
1963 
1964         ierr = PetscSectionGetDof(coordSection, vertex, &dof);CHKERRQ(ierr);
1965         ierr = PetscSectionGetOffset(coordSection, vertex, &off);CHKERRQ(ierr);
1966         ierr = PetscSectionGetDof(subCoordSection, subvertex, &sdof);CHKERRQ(ierr);
1967         ierr = PetscSectionGetOffset(subCoordSection, subvertex, &soff);CHKERRQ(ierr);
1968         if (dof != sdof) SETERRQ4(comm, PETSC_ERR_PLIB, "Coordinate dimension %d on subvertex %d, vertex %d should be %d", sdof, subvertex, vertex, dof);
1969         for (d = 0; d < dof; ++d) subCoords[soff+d] = coords[off+d];
1970       }
1971       ierr = VecRestoreArray(coordinates,    &coords);CHKERRQ(ierr);
1972       ierr = VecRestoreArray(subCoordinates, &subCoords);CHKERRQ(ierr);
1973     }
1974     ierr = DMSetCoordinatesLocal(subdm, subCoordinates);CHKERRQ(ierr);
1975     ierr = VecDestroy(&subCoordinates);CHKERRQ(ierr);
1976   }
1977   /* Cleanup */
1978   if (subvertexIS) {ierr = ISRestoreIndices(subvertexIS, &subVertices);CHKERRQ(ierr);}
1979   ierr = ISDestroy(&subvertexIS);CHKERRQ(ierr);
1980   if (subcellIS) {ierr = ISRestoreIndices(subcellIS, &subCells);CHKERRQ(ierr);}
1981   ierr = ISDestroy(&subcellIS);CHKERRQ(ierr);
1982   PetscFunctionReturn(0);
1983 }
1984 
1985 #undef __FUNCT__
1986 #define __FUNCT__ "DMPlexCreateSubmesh_Interpolated"
1987 static PetscErrorCode DMPlexCreateSubmesh_Interpolated(DM dm, const char vertexLabelName[], PetscInt value, DM subdm)
1988 {
1989   MPI_Comm         comm;
1990   DMLabel          subpointMap, vertexLabel;
1991   IS              *subpointIS;
1992   const PetscInt **subpoints;
1993   PetscInt        *numSubPoints, *firstSubPoint, *coneNew, *coneONew;
1994   PetscInt         totSubPoints = 0, maxConeSize, dim, p, d, v;
1995   PetscErrorCode   ierr;
1996 
1997   PetscFunctionBegin;
1998   ierr = PetscObjectGetComm((PetscObject)dm,&comm);CHKERRQ(ierr);
1999   /* Create subpointMap which marks the submesh */
2000   ierr = DMLabelCreate("subpoint_map", &subpointMap);CHKERRQ(ierr);
2001   ierr = DMPlexSetSubpointMap(subdm, subpointMap);CHKERRQ(ierr);
2002   ierr = DMLabelDestroy(&subpointMap);CHKERRQ(ierr);
2003   ierr = DMPlexGetLabel(dm, vertexLabelName, &vertexLabel);CHKERRQ(ierr);
2004   ierr = DMPlexMarkSubmesh_Interpolated(dm, vertexLabel, value, subpointMap, subdm);CHKERRQ(ierr);
2005   /* Setup chart */
2006   ierr = DMPlexGetDimension(dm, &dim);CHKERRQ(ierr);
2007   ierr = PetscMalloc4(dim+1,PetscInt,&numSubPoints,dim+1,PetscInt,&firstSubPoint,dim+1,IS,&subpointIS,dim+1,const PetscInt *,&subpoints);CHKERRQ(ierr);
2008   for (d = 0; d <= dim; ++d) {
2009     ierr = DMLabelGetStratumSize(subpointMap, d, &numSubPoints[d]);CHKERRQ(ierr);
2010     totSubPoints += numSubPoints[d];
2011   }
2012   ierr = DMPlexSetChart(subdm, 0, totSubPoints);CHKERRQ(ierr);
2013   ierr = DMPlexSetVTKCellHeight(subdm, 1);CHKERRQ(ierr);
2014   /* Set cone sizes */
2015   firstSubPoint[dim] = 0;
2016   firstSubPoint[0]   = firstSubPoint[dim] + numSubPoints[dim];
2017   if (dim > 1) {firstSubPoint[dim-1] = firstSubPoint[0]     + numSubPoints[0];}
2018   if (dim > 2) {firstSubPoint[dim-2] = firstSubPoint[dim-1] + numSubPoints[dim-1];}
2019   for (d = 0; d <= dim; ++d) {
2020     ierr = DMLabelGetStratumIS(subpointMap, d, &subpointIS[d]);CHKERRQ(ierr);
2021     ierr = ISGetIndices(subpointIS[d], &subpoints[d]);CHKERRQ(ierr);
2022   }
2023   for (d = 0; d <= dim; ++d) {
2024     for (p = 0; p < numSubPoints[d]; ++p) {
2025       const PetscInt  point    = subpoints[d][p];
2026       const PetscInt  subpoint = firstSubPoint[d] + p;
2027       const PetscInt *cone;
2028       PetscInt        coneSize, coneSizeNew, c, val;
2029 
2030       ierr = DMPlexGetConeSize(dm, point, &coneSize);CHKERRQ(ierr);
2031       ierr = DMPlexSetConeSize(subdm, subpoint, coneSize);CHKERRQ(ierr);
2032       if (d == dim) {
2033         ierr = DMPlexGetCone(dm, point, &cone);CHKERRQ(ierr);
2034         for (c = 0, coneSizeNew = 0; c < coneSize; ++c) {
2035           ierr = DMLabelGetValue(subpointMap, cone[c], &val);CHKERRQ(ierr);
2036           if (val >= 0) coneSizeNew++;
2037         }
2038         ierr = DMPlexSetConeSize(subdm, subpoint, coneSizeNew);CHKERRQ(ierr);
2039       }
2040     }
2041   }
2042   ierr = DMSetUp(subdm);CHKERRQ(ierr);
2043   /* Set cones */
2044   ierr = DMPlexGetMaxSizes(dm, &maxConeSize, NULL);CHKERRQ(ierr);
2045   ierr = PetscMalloc2(maxConeSize,PetscInt,&coneNew,maxConeSize,PetscInt,&coneONew);CHKERRQ(ierr);
2046   for (d = 0; d <= dim; ++d) {
2047     for (p = 0; p < numSubPoints[d]; ++p) {
2048       const PetscInt  point    = subpoints[d][p];
2049       const PetscInt  subpoint = firstSubPoint[d] + p;
2050       const PetscInt *cone, *ornt;
2051       PetscInt        coneSize, subconeSize, coneSizeNew, c, subc;
2052 
2053       ierr = DMPlexGetConeSize(dm, point, &coneSize);CHKERRQ(ierr);
2054       ierr = DMPlexGetConeSize(subdm, subpoint, &subconeSize);CHKERRQ(ierr);
2055       ierr = DMPlexGetCone(dm, point, &cone);CHKERRQ(ierr);
2056       ierr = DMPlexGetConeOrientation(dm, point, &ornt);CHKERRQ(ierr);
2057       for (c = 0, coneSizeNew = 0; c < coneSize; ++c) {
2058         ierr = PetscFindInt(cone[c], numSubPoints[d-1], subpoints[d-1], &subc);CHKERRQ(ierr);
2059         if (subc >= 0) {
2060           coneNew[coneSizeNew]  = firstSubPoint[d-1] + subc;
2061           coneONew[coneSizeNew] = ornt[c];
2062           ++coneSizeNew;
2063         }
2064       }
2065       if (coneSizeNew != subconeSize) SETERRQ2(comm, PETSC_ERR_PLIB, "Number of cone points located %d does not match subcone size %d", coneSizeNew, subconeSize);
2066       ierr = DMPlexSetCone(subdm, subpoint, coneNew);CHKERRQ(ierr);
2067       ierr = DMPlexSetConeOrientation(subdm, subpoint, coneONew);CHKERRQ(ierr);
2068     }
2069   }
2070   ierr = PetscFree2(coneNew,coneONew);CHKERRQ(ierr);
2071   ierr = DMPlexSymmetrize(subdm);CHKERRQ(ierr);
2072   ierr = DMPlexStratify(subdm);CHKERRQ(ierr);
2073   /* Build coordinates */
2074   {
2075     PetscSection coordSection, subCoordSection;
2076     Vec          coordinates, subCoordinates;
2077     PetscScalar *coords, *subCoords;
2078     PetscInt     numComp, coordSize;
2079 
2080     ierr = DMPlexGetCoordinateSection(dm, &coordSection);CHKERRQ(ierr);
2081     ierr = DMGetCoordinatesLocal(dm, &coordinates);CHKERRQ(ierr);
2082     ierr = DMPlexGetCoordinateSection(subdm, &subCoordSection);CHKERRQ(ierr);
2083     ierr = PetscSectionSetNumFields(subCoordSection, 1);CHKERRQ(ierr);
2084     ierr = PetscSectionGetFieldComponents(coordSection, 0, &numComp);CHKERRQ(ierr);
2085     ierr = PetscSectionSetFieldComponents(subCoordSection, 0, numComp);CHKERRQ(ierr);
2086     ierr = PetscSectionSetChart(subCoordSection, firstSubPoint[0], firstSubPoint[0]+numSubPoints[0]);CHKERRQ(ierr);
2087     for (v = 0; v < numSubPoints[0]; ++v) {
2088       const PetscInt vertex    = subpoints[0][v];
2089       const PetscInt subvertex = firstSubPoint[0]+v;
2090       PetscInt       dof;
2091 
2092       ierr = PetscSectionGetDof(coordSection, vertex, &dof);CHKERRQ(ierr);
2093       ierr = PetscSectionSetDof(subCoordSection, subvertex, dof);CHKERRQ(ierr);
2094       ierr = PetscSectionSetFieldDof(subCoordSection, subvertex, 0, dof);CHKERRQ(ierr);
2095     }
2096     ierr = PetscSectionSetUp(subCoordSection);CHKERRQ(ierr);
2097     ierr = PetscSectionGetStorageSize(subCoordSection, &coordSize);CHKERRQ(ierr);
2098     ierr = VecCreate(comm, &subCoordinates);CHKERRQ(ierr);
2099     ierr = VecSetSizes(subCoordinates, coordSize, PETSC_DETERMINE);CHKERRQ(ierr);
2100     ierr = VecSetFromOptions(subCoordinates);CHKERRQ(ierr);
2101     ierr = VecGetArray(coordinates,    &coords);CHKERRQ(ierr);
2102     ierr = VecGetArray(subCoordinates, &subCoords);CHKERRQ(ierr);
2103     for (v = 0; v < numSubPoints[0]; ++v) {
2104       const PetscInt vertex    = subpoints[0][v];
2105       const PetscInt subvertex = firstSubPoint[0]+v;
2106       PetscInt dof, off, sdof, soff, d;
2107 
2108       ierr = PetscSectionGetDof(coordSection, vertex, &dof);CHKERRQ(ierr);
2109       ierr = PetscSectionGetOffset(coordSection, vertex, &off);CHKERRQ(ierr);
2110       ierr = PetscSectionGetDof(subCoordSection, subvertex, &sdof);CHKERRQ(ierr);
2111       ierr = PetscSectionGetOffset(subCoordSection, subvertex, &soff);CHKERRQ(ierr);
2112       if (dof != sdof) SETERRQ4(comm, PETSC_ERR_PLIB, "Coordinate dimension %d on subvertex %d, vertex %d should be %d", sdof, subvertex, vertex, dof);
2113       for (d = 0; d < dof; ++d) subCoords[soff+d] = coords[off+d];
2114     }
2115     ierr = VecRestoreArray(coordinates,    &coords);CHKERRQ(ierr);
2116     ierr = VecRestoreArray(subCoordinates, &subCoords);CHKERRQ(ierr);
2117     ierr = DMSetCoordinatesLocal(subdm, subCoordinates);CHKERRQ(ierr);
2118     ierr = VecDestroy(&subCoordinates);CHKERRQ(ierr);
2119   }
2120   /* Cleanup */
2121   for (d = 0; d <= dim; ++d) {
2122     ierr = ISRestoreIndices(subpointIS[d], &subpoints[d]);CHKERRQ(ierr);
2123     ierr = ISDestroy(&subpointIS[d]);CHKERRQ(ierr);
2124   }
2125   ierr = PetscFree4(numSubPoints,firstSubPoint,subpointIS,subpoints);CHKERRQ(ierr);
2126   PetscFunctionReturn(0);
2127 }
2128 
2129 #undef __FUNCT__
2130 #define __FUNCT__ "DMPlexCreateSubmesh"
2131 /*@C
2132   DMPlexCreateSubmesh - Extract a hypersurface from the mesh using vertices defined by a label
2133 
2134   Input Parameters:
2135 + dm           - The original mesh
2136 . vertexLabel  - The DMLabel marking vertices contained in the surface
2137 - value        - The label value to use
2138 
2139   Output Parameter:
2140 . subdm - The surface mesh
2141 
2142   Note: This function produces a DMLabel mapping original points in the submesh to their depth. This can be obtained using DMPlexGetSubpointMap().
2143 
2144   Level: developer
2145 
2146 .seealso: DMPlexGetSubpointMap(), DMPlexGetLabel(), DMLabelSetValue()
2147 @*/
2148 PetscErrorCode DMPlexCreateSubmesh(DM dm, const char vertexLabel[], PetscInt value, DM *subdm)
2149 {
2150   PetscInt       dim, depth;
2151   PetscErrorCode ierr;
2152 
2153   PetscFunctionBegin;
2154   PetscValidHeaderSpecific(dm, DM_CLASSID, 1);
2155   PetscValidCharPointer(vertexLabel, 2);
2156   PetscValidPointer(subdm, 3);
2157   ierr = DMPlexGetDimension(dm, &dim);CHKERRQ(ierr);
2158   ierr = DMPlexGetDepth(dm, &depth);CHKERRQ(ierr);
2159   ierr = DMCreate(PetscObjectComm((PetscObject)dm), subdm);CHKERRQ(ierr);
2160   ierr = DMSetType(*subdm, DMPLEX);CHKERRQ(ierr);
2161   ierr = DMPlexSetDimension(*subdm, dim-1);CHKERRQ(ierr);
2162   if (depth == dim) {
2163     ierr = DMPlexCreateSubmesh_Interpolated(dm, vertexLabel, value, *subdm);CHKERRQ(ierr);
2164   } else {
2165     ierr = DMPlexCreateSubmesh_Uninterpolated(dm, vertexLabel, value, *subdm);CHKERRQ(ierr);
2166   }
2167   PetscFunctionReturn(0);
2168 }
2169 
2170 #undef __FUNCT__
2171 #define __FUNCT__ "DMPlexCreateCohesiveSubmesh_Uninterpolated"
2172 static PetscErrorCode DMPlexCreateCohesiveSubmesh_Uninterpolated(DM dm, PetscBool hasLagrange, DM subdm)
2173 {
2174   MPI_Comm        comm;
2175   DMLabel         subpointMap;
2176   IS              subvertexIS;
2177   const PetscInt *subVertices;
2178   PetscInt        numSubVertices, firstSubVertex, numSubCells, *subCells;
2179   PetscInt       *subface, maxConeSize, numSubFaces, firstSubFace, newFacePoint, nFV;
2180   PetscInt        cMax, c, f;
2181   PetscErrorCode  ierr;
2182 
2183   PetscFunctionBegin;
2184   ierr = PetscObjectGetComm((PetscObject)dm, &comm);CHKERRQ(ierr);
2185   /* Create subpointMap which marks the submesh */
2186   ierr = DMLabelCreate("subpoint_map", &subpointMap);CHKERRQ(ierr);
2187   ierr = DMPlexSetSubpointMap(subdm, subpointMap);CHKERRQ(ierr);
2188   ierr = DMLabelDestroy(&subpointMap);CHKERRQ(ierr);
2189   ierr = DMPlexMarkCohesiveSubmesh_Uninterpolated(dm, hasLagrange, subpointMap, &numSubFaces, &nFV, &subCells, subdm);CHKERRQ(ierr);
2190   /* Setup chart */
2191   ierr = DMLabelGetStratumSize(subpointMap, 0, &numSubVertices);CHKERRQ(ierr);
2192   ierr = DMLabelGetStratumSize(subpointMap, 2, &numSubCells);CHKERRQ(ierr);
2193   ierr = DMPlexSetChart(subdm, 0, numSubCells+numSubFaces+numSubVertices);CHKERRQ(ierr);
2194   ierr = DMPlexSetVTKCellHeight(subdm, 1);CHKERRQ(ierr);
2195   /* Set cone sizes */
2196   firstSubVertex = numSubCells;
2197   firstSubFace   = numSubCells+numSubVertices;
2198   newFacePoint   = firstSubFace;
2199   ierr = DMLabelGetStratumIS(subpointMap, 0, &subvertexIS);CHKERRQ(ierr);
2200   if (subvertexIS) {ierr = ISGetIndices(subvertexIS, &subVertices);CHKERRQ(ierr);}
2201   for (c = 0; c < numSubCells; ++c) {
2202     ierr = DMPlexSetConeSize(subdm, c, 1);CHKERRQ(ierr);
2203   }
2204   for (f = firstSubFace; f < firstSubFace+numSubFaces; ++f) {
2205     ierr = DMPlexSetConeSize(subdm, f, nFV);CHKERRQ(ierr);
2206   }
2207   ierr = DMSetUp(subdm);CHKERRQ(ierr);
2208   /* Create face cones */
2209   ierr = DMPlexGetMaxSizes(dm, &maxConeSize, NULL);CHKERRQ(ierr);
2210   ierr = DMPlexGetHybridBounds(dm, &cMax, NULL, NULL, NULL);CHKERRQ(ierr);
2211   ierr = DMGetWorkArray(subdm, maxConeSize, PETSC_INT, (void**) &subface);CHKERRQ(ierr);
2212   for (c = 0; c < numSubCells; ++c) {
2213     const PetscInt  cell    = subCells[c];
2214     const PetscInt  subcell = c;
2215     const PetscInt *cone, *cells;
2216     PetscInt        numCells, subVertex, p, v;
2217 
2218     if (cell < cMax) continue;
2219     ierr = DMPlexGetCone(dm, cell, &cone);CHKERRQ(ierr);
2220     for (v = 0; v < nFV; ++v) {
2221       ierr = PetscFindInt(cone[v], numSubVertices, subVertices, &subVertex);CHKERRQ(ierr);
2222       subface[v] = firstSubVertex+subVertex;
2223     }
2224     ierr = DMPlexSetCone(subdm, newFacePoint, subface);CHKERRQ(ierr);
2225     ierr = DMPlexSetCone(subdm, subcell, &newFacePoint);CHKERRQ(ierr);
2226     ierr = DMPlexGetJoin(dm, nFV, cone, &numCells, &cells);CHKERRQ(ierr);
2227     if (numCells != 2) SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Cohesive cells should separate two cells");
2228     for (p = 0; p < numCells; ++p) {
2229       PetscInt negsubcell;
2230 
2231       if (cells[p] >= cMax) continue;
2232       /* I know this is a crap search */
2233       for (negsubcell = 0; negsubcell < numSubCells; ++negsubcell) {
2234         if (subCells[negsubcell] == cells[p]) break;
2235       }
2236       if (negsubcell == numSubCells) SETERRQ1(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Could not find negative face neighbor for cohesive cell %d", cell);
2237       ierr = DMPlexSetCone(subdm, negsubcell, &newFacePoint);CHKERRQ(ierr);
2238     }
2239     ierr = DMPlexRestoreJoin(dm, nFV, cone, &numCells, &cells);CHKERRQ(ierr);
2240     ++newFacePoint;
2241   }
2242   ierr = DMRestoreWorkArray(subdm, maxConeSize, PETSC_INT, (void**) &subface);CHKERRQ(ierr);
2243   ierr = DMPlexSymmetrize(subdm);CHKERRQ(ierr);
2244   ierr = DMPlexStratify(subdm);CHKERRQ(ierr);
2245   /* Build coordinates */
2246   {
2247     PetscSection coordSection, subCoordSection;
2248     Vec          coordinates, subCoordinates;
2249     PetscScalar *coords, *subCoords;
2250     PetscInt     numComp, coordSize, v;
2251 
2252     ierr = DMPlexGetCoordinateSection(dm, &coordSection);CHKERRQ(ierr);
2253     ierr = DMGetCoordinatesLocal(dm, &coordinates);CHKERRQ(ierr);
2254     ierr = DMPlexGetCoordinateSection(subdm, &subCoordSection);CHKERRQ(ierr);
2255     ierr = PetscSectionSetNumFields(subCoordSection, 1);CHKERRQ(ierr);
2256     ierr = PetscSectionGetFieldComponents(coordSection, 0, &numComp);CHKERRQ(ierr);
2257     ierr = PetscSectionSetFieldComponents(subCoordSection, 0, numComp);CHKERRQ(ierr);
2258     ierr = PetscSectionSetChart(subCoordSection, firstSubVertex, firstSubVertex+numSubVertices);CHKERRQ(ierr);
2259     for (v = 0; v < numSubVertices; ++v) {
2260       const PetscInt vertex    = subVertices[v];
2261       const PetscInt subvertex = firstSubVertex+v;
2262       PetscInt       dof;
2263 
2264       ierr = PetscSectionGetDof(coordSection, vertex, &dof);CHKERRQ(ierr);
2265       ierr = PetscSectionSetDof(subCoordSection, subvertex, dof);CHKERRQ(ierr);
2266       ierr = PetscSectionSetFieldDof(subCoordSection, subvertex, 0, dof);CHKERRQ(ierr);
2267     }
2268     ierr = PetscSectionSetUp(subCoordSection);CHKERRQ(ierr);
2269     ierr = PetscSectionGetStorageSize(subCoordSection, &coordSize);CHKERRQ(ierr);
2270     ierr = VecCreate(comm, &subCoordinates);CHKERRQ(ierr);
2271     if (coordSize) {
2272       ierr = VecSetSizes(subCoordinates, coordSize, PETSC_DETERMINE);CHKERRQ(ierr);
2273       ierr = VecSetFromOptions(subCoordinates);CHKERRQ(ierr);
2274       ierr = VecGetArray(coordinates,    &coords);CHKERRQ(ierr);
2275       ierr = VecGetArray(subCoordinates, &subCoords);CHKERRQ(ierr);
2276       for (v = 0; v < numSubVertices; ++v) {
2277         const PetscInt vertex    = subVertices[v];
2278         const PetscInt subvertex = firstSubVertex+v;
2279         PetscInt       dof, off, sdof, soff, d;
2280 
2281         ierr = PetscSectionGetDof(coordSection, vertex, &dof);CHKERRQ(ierr);
2282         ierr = PetscSectionGetOffset(coordSection, vertex, &off);CHKERRQ(ierr);
2283         ierr = PetscSectionGetDof(subCoordSection, subvertex, &sdof);CHKERRQ(ierr);
2284         ierr = PetscSectionGetOffset(subCoordSection, subvertex, &soff);CHKERRQ(ierr);
2285         if (dof != sdof) SETERRQ4(comm, PETSC_ERR_PLIB, "Coordinate dimension %d on subvertex %d, vertex %d should be %d", sdof, subvertex, vertex, dof);
2286         for (d = 0; d < dof; ++d) subCoords[soff+d] = coords[off+d];
2287       }
2288       ierr = VecRestoreArray(coordinates,    &coords);CHKERRQ(ierr);
2289       ierr = VecRestoreArray(subCoordinates, &subCoords);CHKERRQ(ierr);
2290     }
2291     ierr = DMSetCoordinatesLocal(subdm, subCoordinates);CHKERRQ(ierr);
2292     ierr = VecDestroy(&subCoordinates);CHKERRQ(ierr);
2293   }
2294   /* Cleanup */
2295   if (subvertexIS) {ierr = ISRestoreIndices(subvertexIS, &subVertices);CHKERRQ(ierr);}
2296   ierr = ISDestroy(&subvertexIS);CHKERRQ(ierr);
2297   ierr = PetscFree(subCells);CHKERRQ(ierr);
2298   PetscFunctionReturn(0);
2299 }
2300 
2301 #undef __FUNCT__
2302 #define __FUNCT__ "DMPlexCreateCohesiveSubmesh_Interpolated"
2303 static PetscErrorCode DMPlexCreateCohesiveSubmesh_Interpolated(DM dm, PetscBool hasLagrange, DM subdm)
2304 {
2305   MPI_Comm         comm;
2306   DMLabel          subpointMap;
2307   IS              *subpointIS;
2308   const PetscInt **subpoints;
2309   PetscInt        *numSubPoints, *firstSubPoint, *coneNew;
2310   PetscInt         totSubPoints = 0, maxConeSize, dim, p, d, v;
2311   PetscErrorCode   ierr;
2312 
2313   PetscFunctionBegin;
2314   ierr = PetscObjectGetComm((PetscObject)dm,&comm);CHKERRQ(ierr);
2315   /* Create subpointMap which marks the submesh */
2316   ierr = DMLabelCreate("subpoint_map", &subpointMap);CHKERRQ(ierr);
2317   ierr = DMPlexSetSubpointMap(subdm, subpointMap);CHKERRQ(ierr);
2318   ierr = DMLabelDestroy(&subpointMap);CHKERRQ(ierr);
2319   ierr = DMPlexMarkCohesiveSubmesh_Interpolated(dm, hasLagrange, subpointMap, subdm);CHKERRQ(ierr);
2320   /* Setup chart */
2321   ierr = DMPlexGetDimension(dm, &dim);CHKERRQ(ierr);
2322   ierr = PetscMalloc4(dim+1,PetscInt,&numSubPoints,dim+1,PetscInt,&firstSubPoint,dim+1,IS,&subpointIS,dim+1,const PetscInt *,&subpoints);CHKERRQ(ierr);
2323   for (d = 0; d <= dim; ++d) {
2324     ierr = DMLabelGetStratumSize(subpointMap, d, &numSubPoints[d]);CHKERRQ(ierr);
2325     totSubPoints += numSubPoints[d];
2326   }
2327   ierr = DMPlexSetChart(subdm, 0, totSubPoints);CHKERRQ(ierr);
2328   ierr = DMPlexSetVTKCellHeight(subdm, 1);CHKERRQ(ierr);
2329   /* Set cone sizes */
2330   firstSubPoint[dim] = 0;
2331   firstSubPoint[0]   = firstSubPoint[dim] + numSubPoints[dim];
2332   if (dim > 1) {firstSubPoint[dim-1] = firstSubPoint[0]     + numSubPoints[0];}
2333   if (dim > 2) {firstSubPoint[dim-2] = firstSubPoint[dim-1] + numSubPoints[dim-1];}
2334   for (d = 0; d <= dim; ++d) {
2335     ierr = DMLabelGetStratumIS(subpointMap, d, &subpointIS[d]);CHKERRQ(ierr);
2336     ierr = ISGetIndices(subpointIS[d], &subpoints[d]);CHKERRQ(ierr);
2337   }
2338   for (d = 0; d <= dim; ++d) {
2339     for (p = 0; p < numSubPoints[d]; ++p) {
2340       const PetscInt  point    = subpoints[d][p];
2341       const PetscInt  subpoint = firstSubPoint[d] + p;
2342       const PetscInt *cone;
2343       PetscInt        coneSize, coneSizeNew, c, val;
2344 
2345       ierr = DMPlexGetConeSize(dm, point, &coneSize);CHKERRQ(ierr);
2346       ierr = DMPlexSetConeSize(subdm, subpoint, coneSize);CHKERRQ(ierr);
2347       if (d == dim) {
2348         ierr = DMPlexGetCone(dm, point, &cone);CHKERRQ(ierr);
2349         for (c = 0, coneSizeNew = 0; c < coneSize; ++c) {
2350           ierr = DMLabelGetValue(subpointMap, cone[c], &val);CHKERRQ(ierr);
2351           if (val >= 0) coneSizeNew++;
2352         }
2353         ierr = DMPlexSetConeSize(subdm, subpoint, coneSizeNew);CHKERRQ(ierr);
2354       }
2355     }
2356   }
2357   ierr = DMSetUp(subdm);CHKERRQ(ierr);
2358   /* Set cones */
2359   ierr = DMPlexGetMaxSizes(dm, &maxConeSize, NULL);CHKERRQ(ierr);
2360   ierr = PetscMalloc(maxConeSize * sizeof(PetscInt), &coneNew);CHKERRQ(ierr);
2361   for (d = 0; d <= dim; ++d) {
2362     for (p = 0; p < numSubPoints[d]; ++p) {
2363       const PetscInt  point    = subpoints[d][p];
2364       const PetscInt  subpoint = firstSubPoint[d] + p;
2365       const PetscInt *cone;
2366       PetscInt        coneSize, subconeSize, coneSizeNew, c, subc;
2367 
2368       ierr = DMPlexGetConeSize(dm, point, &coneSize);CHKERRQ(ierr);
2369       ierr = DMPlexGetConeSize(subdm, subpoint, &subconeSize);CHKERRQ(ierr);
2370       ierr = DMPlexGetCone(dm, point, &cone);CHKERRQ(ierr);
2371       for (c = 0, coneSizeNew = 0; c < coneSize; ++c) {
2372         ierr = PetscFindInt(cone[c], numSubPoints[d-1], subpoints[d-1], &subc);CHKERRQ(ierr);
2373         if (subc >= 0) coneNew[coneSizeNew++] = firstSubPoint[d-1] + subc;
2374       }
2375       if (coneSizeNew != subconeSize) SETERRQ2(comm, PETSC_ERR_PLIB, "Number of cone points located %d does not match subcone size %d", coneSizeNew, subconeSize);
2376       ierr = DMPlexSetCone(subdm, subpoint, coneNew);CHKERRQ(ierr);
2377     }
2378   }
2379   ierr = PetscFree(coneNew);CHKERRQ(ierr);
2380   ierr = DMPlexSymmetrize(subdm);CHKERRQ(ierr);
2381   ierr = DMPlexStratify(subdm);CHKERRQ(ierr);
2382   /* Build coordinates */
2383   {
2384     PetscSection coordSection, subCoordSection;
2385     Vec          coordinates, subCoordinates;
2386     PetscScalar *coords, *subCoords;
2387     PetscInt     numComp, coordSize;
2388 
2389     ierr = DMPlexGetCoordinateSection(dm, &coordSection);CHKERRQ(ierr);
2390     ierr = DMGetCoordinatesLocal(dm, &coordinates);CHKERRQ(ierr);
2391     ierr = DMPlexGetCoordinateSection(subdm, &subCoordSection);CHKERRQ(ierr);
2392     ierr = PetscSectionSetNumFields(subCoordSection, 1);CHKERRQ(ierr);
2393     ierr = PetscSectionGetFieldComponents(coordSection, 0, &numComp);CHKERRQ(ierr);
2394     ierr = PetscSectionSetFieldComponents(subCoordSection, 0, numComp);CHKERRQ(ierr);
2395     ierr = PetscSectionSetChart(subCoordSection, firstSubPoint[0], firstSubPoint[0]+numSubPoints[0]);CHKERRQ(ierr);
2396     for (v = 0; v < numSubPoints[0]; ++v) {
2397       const PetscInt vertex    = subpoints[0][v];
2398       const PetscInt subvertex = firstSubPoint[0]+v;
2399       PetscInt       dof;
2400 
2401       ierr = PetscSectionGetDof(coordSection, vertex, &dof);CHKERRQ(ierr);
2402       ierr = PetscSectionSetDof(subCoordSection, subvertex, dof);CHKERRQ(ierr);
2403       ierr = PetscSectionSetFieldDof(subCoordSection, subvertex, 0, dof);CHKERRQ(ierr);
2404     }
2405     ierr = PetscSectionSetUp(subCoordSection);CHKERRQ(ierr);
2406     ierr = PetscSectionGetStorageSize(subCoordSection, &coordSize);CHKERRQ(ierr);
2407     ierr = VecCreate(comm, &subCoordinates);CHKERRQ(ierr);
2408     ierr = VecSetSizes(subCoordinates, coordSize, PETSC_DETERMINE);CHKERRQ(ierr);
2409     ierr = VecSetFromOptions(subCoordinates);CHKERRQ(ierr);
2410     ierr = VecGetArray(coordinates,    &coords);CHKERRQ(ierr);
2411     ierr = VecGetArray(subCoordinates, &subCoords);CHKERRQ(ierr);
2412     for (v = 0; v < numSubPoints[0]; ++v) {
2413       const PetscInt vertex    = subpoints[0][v];
2414       const PetscInt subvertex = firstSubPoint[0]+v;
2415       PetscInt dof, off, sdof, soff, d;
2416 
2417       ierr = PetscSectionGetDof(coordSection, vertex, &dof);CHKERRQ(ierr);
2418       ierr = PetscSectionGetOffset(coordSection, vertex, &off);CHKERRQ(ierr);
2419       ierr = PetscSectionGetDof(subCoordSection, subvertex, &sdof);CHKERRQ(ierr);
2420       ierr = PetscSectionGetOffset(subCoordSection, subvertex, &soff);CHKERRQ(ierr);
2421       if (dof != sdof) SETERRQ4(comm, PETSC_ERR_PLIB, "Coordinate dimension %d on subvertex %d, vertex %d should be %d", sdof, subvertex, vertex, dof);
2422       for (d = 0; d < dof; ++d) subCoords[soff+d] = coords[off+d];
2423     }
2424     ierr = VecRestoreArray(coordinates,    &coords);CHKERRQ(ierr);
2425     ierr = VecRestoreArray(subCoordinates, &subCoords);CHKERRQ(ierr);
2426     ierr = DMSetCoordinatesLocal(subdm, subCoordinates);CHKERRQ(ierr);
2427     ierr = VecDestroy(&subCoordinates);CHKERRQ(ierr);
2428   }
2429   /* Cleanup */
2430   for (d = 0; d <= dim; ++d) {
2431     ierr = ISRestoreIndices(subpointIS[d], &subpoints[d]);CHKERRQ(ierr);
2432     ierr = ISDestroy(&subpointIS[d]);CHKERRQ(ierr);
2433   }
2434   ierr = PetscFree4(numSubPoints,firstSubPoint,subpointIS,subpoints);CHKERRQ(ierr);
2435   PetscFunctionReturn(0);
2436 }
2437 
2438 #undef __FUNCT__
2439 #define __FUNCT__ "DMPlexCreateCohesiveSubmesh"
2440 /*
2441   DMPlexCreateCohesiveSubmesh - Extract from a mesh with cohesive cells the hypersurface defined by one face of the cells.
2442 
2443   Input Parameters:
2444 + dm          - The original mesh
2445 - hasLagrange - The mesh has Lagrange unknowns in the cohesive cells
2446 
2447   Output Parameter:
2448 . subdm - The surface mesh
2449 
2450   Note: This function produces a DMLabel mapping original points in the submesh to their depth. This can be obtained using DMPlexGetSubpointMap().
2451 
2452   Level: developer
2453 
2454 .seealso: DMPlexGetSubpointMap(), DMPlexCreateSubmesh()
2455 */
2456 PetscErrorCode DMPlexCreateCohesiveSubmesh(DM dm, PetscBool hasLagrange, DM *subdm)
2457 {
2458   PetscInt       dim, depth;
2459   PetscErrorCode ierr;
2460 
2461   PetscFunctionBegin;
2462   PetscValidHeaderSpecific(dm, DM_CLASSID, 1);
2463   PetscValidPointer(subdm, 3);
2464   ierr = DMPlexGetDimension(dm, &dim);CHKERRQ(ierr);
2465   ierr = DMPlexGetDepth(dm, &depth);CHKERRQ(ierr);
2466   ierr = DMCreate(PetscObjectComm((PetscObject)dm), subdm);CHKERRQ(ierr);
2467   ierr = DMSetType(*subdm, DMPLEX);CHKERRQ(ierr);
2468   ierr = DMPlexSetDimension(*subdm, dim-1);CHKERRQ(ierr);
2469   if (depth == dim) {
2470     ierr = DMPlexCreateCohesiveSubmesh_Interpolated(dm, hasLagrange, *subdm);CHKERRQ(ierr);
2471   } else {
2472     ierr = DMPlexCreateCohesiveSubmesh_Uninterpolated(dm, hasLagrange, *subdm);CHKERRQ(ierr);
2473   }
2474   PetscFunctionReturn(0);
2475 }
2476 
2477 #undef __FUNCT__
2478 #define __FUNCT__ "DMPlexGetSubpointMap"
2479 /*@
2480   DMPlexGetSubpointMap - Returns a DMLabel with point dimension as values
2481 
2482   Input Parameter:
2483 . dm - The submesh DM
2484 
2485   Output Parameter:
2486 . subpointMap - The DMLabel of all the points from the original mesh in this submesh, or NULL if this is not a submesh
2487 
2488   Level: developer
2489 
2490 .seealso: DMPlexCreateSubmesh(), DMPlexCreateSubpointIS()
2491 @*/
2492 PetscErrorCode DMPlexGetSubpointMap(DM dm, DMLabel *subpointMap)
2493 {
2494   DM_Plex *mesh = (DM_Plex*) dm->data;
2495 
2496   PetscFunctionBegin;
2497   PetscValidHeaderSpecific(dm, DM_CLASSID, 1);
2498   PetscValidPointer(subpointMap, 2);
2499   *subpointMap = mesh->subpointMap;
2500   PetscFunctionReturn(0);
2501 }
2502 
2503 #undef __FUNCT__
2504 #define __FUNCT__ "DMPlexSetSubpointMap"
2505 /* Note: Should normally not be called by the user, since it is set in DMPlexCreateSubmesh() */
2506 PetscErrorCode DMPlexSetSubpointMap(DM dm, DMLabel subpointMap)
2507 {
2508   DM_Plex       *mesh = (DM_Plex *) dm->data;
2509   DMLabel        tmp;
2510   PetscErrorCode ierr;
2511 
2512   PetscFunctionBegin;
2513   PetscValidHeaderSpecific(dm, DM_CLASSID, 1);
2514   tmp  = mesh->subpointMap;
2515   mesh->subpointMap = subpointMap;
2516   ++mesh->subpointMap->refct;
2517   ierr = DMLabelDestroy(&tmp);CHKERRQ(ierr);
2518   PetscFunctionReturn(0);
2519 }
2520 
2521 #undef __FUNCT__
2522 #define __FUNCT__ "DMPlexCreateSubpointIS"
2523 /*@
2524   DMPlexCreateSubpointIS - Creates an IS covering the entire subdm chart with the original points as data
2525 
2526   Input Parameter:
2527 . dm - The submesh DM
2528 
2529   Output Parameter:
2530 . subpointIS - The IS of all the points from the original mesh in this submesh, or NULL if this is not a submesh
2531 
2532   Note: This is IS is guaranteed to be sorted by the construction of the submesh
2533 
2534   Level: developer
2535 
2536 .seealso: DMPlexCreateSubmesh(), DMPlexGetSubpointMap()
2537 @*/
2538 PetscErrorCode DMPlexCreateSubpointIS(DM dm, IS *subpointIS)
2539 {
2540   MPI_Comm        comm;
2541   DMLabel         subpointMap;
2542   IS              is;
2543   const PetscInt *opoints;
2544   PetscInt       *points, *depths;
2545   PetscInt        depth, depStart, depEnd, d, pStart, pEnd, p, n, off;
2546   PetscErrorCode  ierr;
2547 
2548   PetscFunctionBegin;
2549   PetscValidHeaderSpecific(dm, DM_CLASSID, 1);
2550   PetscValidPointer(subpointIS, 2);
2551   ierr = PetscObjectGetComm((PetscObject)dm,&comm);CHKERRQ(ierr);
2552   *subpointIS = NULL;
2553   ierr = DMPlexGetSubpointMap(dm, &subpointMap);CHKERRQ(ierr);
2554   if (subpointMap) {
2555     ierr = DMPlexGetDepth(dm, &depth);CHKERRQ(ierr);
2556     ierr = DMPlexGetChart(dm, &pStart, &pEnd);CHKERRQ(ierr);
2557     if (pStart) SETERRQ1(comm, PETSC_ERR_ARG_WRONG, "Submeshes must start the point numbering at 0, not %d", pStart);
2558     ierr = DMGetWorkArray(dm, depth+1, PETSC_INT, &depths);CHKERRQ(ierr);
2559     depths[0] = depth;
2560     depths[1] = 0;
2561     for(d = 2; d <= depth; ++d) {depths[d] = depth+1 - d;}
2562     ierr = PetscMalloc(pEnd * sizeof(PetscInt), &points);CHKERRQ(ierr);
2563     for(d = 0, off = 0; d <= depth; ++d) {
2564       const PetscInt dep = depths[d];
2565 
2566       ierr = DMPlexGetDepthStratum(dm, dep, &depStart, &depEnd);CHKERRQ(ierr);
2567       ierr = DMLabelGetStratumSize(subpointMap, dep, &n);CHKERRQ(ierr);
2568       if (((d < 2) && (depth > 1)) || (d == 1)) { /* Only check vertices and cells for now since the map is broken for others */
2569         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);
2570       } else {
2571         if (!n) {
2572           if (d == 0) {
2573             /* Missing cells */
2574             for(p = 0; p < depEnd-depStart; ++p, ++off) points[off] = -1;
2575           } else {
2576             /* Missing faces */
2577             for(p = 0; p < depEnd-depStart; ++p, ++off) points[off] = PETSC_MAX_INT;
2578           }
2579         }
2580       }
2581       if (n) {
2582         ierr = DMLabelGetStratumIS(subpointMap, dep, &is);CHKERRQ(ierr);
2583         ierr = ISGetIndices(is, &opoints);CHKERRQ(ierr);
2584         for(p = 0; p < n; ++p, ++off) points[off] = opoints[p];
2585         ierr = ISRestoreIndices(is, &opoints);CHKERRQ(ierr);
2586         ierr = ISDestroy(&is);CHKERRQ(ierr);
2587       }
2588     }
2589     ierr = DMRestoreWorkArray(dm, depth+1, PETSC_INT, &depths);CHKERRQ(ierr);
2590     if (off != pEnd) SETERRQ2(comm, PETSC_ERR_ARG_WRONG, "The number of mapped submesh points %d should be %d", off, pEnd);
2591     ierr = ISCreateGeneral(comm, pEnd, points, PETSC_OWN_POINTER, subpointIS);CHKERRQ(ierr);
2592   }
2593   PetscFunctionReturn(0);
2594 }
2595