xref: /petsc/src/dm/impls/plex/plexsection.c (revision c4762a1b19cd2af06abeed90e8f9d34fb975dd94)
1 #include <petsc/private/dmpleximpl.h>   /*I      "petscdmplex.h"   I*/
2 
3 /* Set the number of dof on each point and separate by fields */
4 static PetscErrorCode DMPlexCreateSectionFields(DM dm, const PetscInt numComp[], PetscSection *section)
5 {
6   DMLabel        depthLabel;
7   PetscInt       depth, Nf, f, pStart, pEnd;
8   PetscBool     *isFE;
9   PetscErrorCode ierr;
10 
11   PetscFunctionBegin;
12   ierr = DMPlexGetDepth(dm, &depth);CHKERRQ(ierr);
13   ierr = DMPlexGetDepthLabel(dm,&depthLabel);CHKERRQ(ierr);
14   ierr = DMGetNumFields(dm, &Nf);CHKERRQ(ierr);
15   ierr = PetscCalloc1(Nf, &isFE);CHKERRQ(ierr);
16   for (f = 0; f < Nf; ++f) {
17     PetscObject  obj;
18     PetscClassId id;
19 
20     ierr = DMGetField(dm, f, NULL, &obj);CHKERRQ(ierr);
21     ierr = PetscObjectGetClassId(obj, &id);CHKERRQ(ierr);
22     if (id == PETSCFE_CLASSID)      {isFE[f] = PETSC_TRUE;}
23     else if (id == PETSCFV_CLASSID) {isFE[f] = PETSC_FALSE;}
24   }
25 
26   ierr = PetscSectionCreate(PetscObjectComm((PetscObject)dm), section);CHKERRQ(ierr);
27   if (Nf > 0) {
28     ierr = PetscSectionSetNumFields(*section, Nf);CHKERRQ(ierr);
29     if (numComp) {
30       for (f = 0; f < Nf; ++f) {
31         ierr = PetscSectionSetFieldComponents(*section, f, numComp[f]);CHKERRQ(ierr);
32         if (isFE[f]) {
33           PetscFE           fe;
34           PetscDualSpace    dspace;
35           const PetscInt    ***perms;
36           const PetscScalar ***flips;
37           const PetscInt    *numDof;
38 
39           ierr = DMGetField(dm,f,NULL,(PetscObject *) &fe);CHKERRQ(ierr);
40           ierr = PetscFEGetDualSpace(fe,&dspace);CHKERRQ(ierr);
41           ierr = PetscDualSpaceGetSymmetries(dspace,&perms,&flips);CHKERRQ(ierr);
42           ierr = PetscDualSpaceGetNumDof(dspace,&numDof);CHKERRQ(ierr);
43           if (perms || flips) {
44             DM              K;
45             PetscInt        h;
46             PetscSectionSym sym;
47 
48             ierr = PetscDualSpaceGetDM(dspace,&K);CHKERRQ(ierr);
49             ierr = PetscSectionSymCreateLabel(PetscObjectComm((PetscObject)*section),depthLabel,&sym);CHKERRQ(ierr);
50             for (h = 0; h <= depth; h++) {
51               PetscDualSpace    hspace;
52               PetscInt          kStart, kEnd;
53               PetscInt          kConeSize;
54               const PetscInt    **perms0 = NULL;
55               const PetscScalar **flips0 = NULL;
56 
57               ierr = PetscDualSpaceGetHeightSubspace(dspace,h,&hspace);CHKERRQ(ierr);
58               ierr = DMPlexGetHeightStratum(K,h,&kStart,&kEnd);CHKERRQ(ierr);
59               if (!hspace) continue;
60               ierr = PetscDualSpaceGetSymmetries(hspace,&perms,&flips);CHKERRQ(ierr);
61               if (perms) perms0 = perms[0];
62               if (flips) flips0 = flips[0];
63               if (!(perms0 || flips0)) continue;
64               ierr = DMPlexGetConeSize(K,kStart,&kConeSize);CHKERRQ(ierr);
65               ierr = PetscSectionSymLabelSetStratum(sym,depth - h,numDof[depth - h],-kConeSize,kConeSize,PETSC_USE_POINTER,perms0 ? &perms0[-kConeSize] : NULL,flips0 ? &flips0[-kConeSize] : NULL);CHKERRQ(ierr);
66             }
67             ierr = PetscSectionSetFieldSym(*section,f,sym);CHKERRQ(ierr);
68             ierr = PetscSectionSymDestroy(&sym);CHKERRQ(ierr);
69           }
70         }
71       }
72     }
73   }
74   ierr = DMPlexGetChart(dm, &pStart, &pEnd);CHKERRQ(ierr);
75   ierr = PetscSectionSetChart(*section, pStart, pEnd);CHKERRQ(ierr);
76   ierr = PetscFree(isFE);CHKERRQ(ierr);
77   PetscFunctionReturn(0);
78 }
79 
80 /* Set the number of dof on each point and separate by fields */
81 static PetscErrorCode DMPlexCreateSectionDof(DM dm, DMLabel label[],const PetscInt numDof[], PetscSection section)
82 {
83   DMLabel        depthLabel;
84   PetscInt      *pMax;
85   PetscInt       depth, cellHeight, pStart = 0, pEnd = 0;
86   PetscInt       Nf, f, dim, d, dep, p;
87   PetscBool     *isFE;
88   PetscErrorCode ierr;
89 
90   PetscFunctionBegin;
91   ierr = DMGetDimension(dm, &dim);CHKERRQ(ierr);
92   ierr = DMPlexGetDepth(dm, &depth);CHKERRQ(ierr);
93   ierr = DMPlexGetDepthLabel(dm,&depthLabel);CHKERRQ(ierr);
94   ierr = DMGetNumFields(dm, &Nf);CHKERRQ(ierr);
95   ierr = PetscMalloc1(Nf, &isFE);CHKERRQ(ierr);
96   for (f = 0; f < Nf; ++f) {
97     PetscObject  obj;
98     PetscClassId id;
99 
100     ierr = DMGetField(dm, f, NULL, &obj);CHKERRQ(ierr);
101     ierr = PetscObjectGetClassId(obj, &id);CHKERRQ(ierr);
102     /* User is allowed to put a "placeholder" field in (c.f. DMCreateDS) */
103     isFE[f] = id == PETSCFE_CLASSID ? PETSC_TRUE : PETSC_FALSE;
104   }
105 
106   ierr = PetscMalloc1(depth+1, &pMax);CHKERRQ(ierr);
107   ierr = DMPlexGetHybridBounds(dm, depth >= 0 ? &pMax[depth] : NULL, depth>1 ? &pMax[depth-1] : NULL, depth>2 ? &pMax[1] : NULL, &pMax[0]);CHKERRQ(ierr);
108   ierr = DMPlexGetVTKCellHeight(dm, &cellHeight);CHKERRQ(ierr);
109   for (f = 0; f < Nf; ++f) {
110     if (label && label[f]) {
111       IS              pointIS;
112       const PetscInt *points;
113       PetscInt        n;
114 
115       ierr = DMLabelGetStratumIS(label[f], 1, &pointIS);CHKERRQ(ierr);
116       if (!pointIS) continue;
117       ierr = ISGetLocalSize(pointIS, &n);CHKERRQ(ierr);
118       ierr = ISGetIndices(pointIS, &points);CHKERRQ(ierr);
119       for (p = 0; p < n; ++p) {
120         const PetscInt point = points[p];
121         PetscInt       dof, d;
122 
123         ierr = DMLabelGetValue(depthLabel, point, &d);CHKERRQ(ierr);
124         ierr = DMPlexGetDepthStratum(dm, d, NULL, &pEnd);CHKERRQ(ierr);
125         /* If this is a hybrid point, use dof for one dimension lower */
126         if ((point >= pMax[d]) && (point < pEnd)) --d;
127         dof  = d < 0 ? 0 : numDof[f*(dim+1)+d];
128         ierr = PetscSectionSetFieldDof(section, point, f, dof);CHKERRQ(ierr);
129         ierr = PetscSectionAddDof(section, point, dof);CHKERRQ(ierr);
130       }
131       ierr = ISRestoreIndices(pointIS, &points);CHKERRQ(ierr);
132       ierr = ISDestroy(&pointIS);CHKERRQ(ierr);
133     } else {
134       for (dep = 0; dep <= depth - cellHeight; ++dep) {
135         /* Cases: dim > depth (cell-vertex mesh), dim == depth (fully interpolated), dim < depth (interpolated submesh) */
136         d    = dim <= depth ? dep : (!dep ? 0 : dim);
137         ierr = DMPlexGetDepthStratum(dm, dep, &pStart, &pEnd);CHKERRQ(ierr);
138         pMax[dep] = pMax[dep] < 0 ? pEnd : pMax[dep];
139         for (p = pStart; p < pEnd; ++p) {
140           const PetscInt dof = numDof[f*(dim+1)+d];
141 
142           if (isFE[f] && p >= pMax[dep]) continue;
143           ierr = PetscSectionSetFieldDof(section, p, f, dof);CHKERRQ(ierr);
144           ierr = PetscSectionAddDof(section, p, dof);CHKERRQ(ierr);
145         }
146       }
147     }
148   }
149   ierr = PetscFree(pMax);CHKERRQ(ierr);
150   ierr = PetscFree(isFE);CHKERRQ(ierr);
151   PetscFunctionReturn(0);
152 }
153 
154 /* Set the number of dof on each point and separate by fields
155    If bcComps is NULL or the IS is NULL, constrain every dof on the point
156 */
157 static PetscErrorCode DMPlexCreateSectionBCDof(DM dm, PetscInt numBC, const PetscInt bcField[], const IS bcComps[], const IS bcPoints[], PetscSection section)
158 {
159   PetscInt       Nf;
160   PetscInt       bc;
161   PetscSection   aSec;
162   PetscErrorCode ierr;
163 
164   PetscFunctionBegin;
165   ierr = PetscSectionGetNumFields(section, &Nf);CHKERRQ(ierr);
166   for (bc = 0; bc < numBC; ++bc) {
167     PetscInt        field = 0;
168     const PetscInt *comp;
169     const PetscInt *idx;
170     PetscInt        Nc = 0, cNc = -1, n, i;
171 
172     if (Nf) {
173       field = bcField[bc];
174       ierr = PetscSectionGetFieldComponents(section, field, &Nc);CHKERRQ(ierr);
175     }
176     if (bcComps && bcComps[bc]) {ierr = ISGetLocalSize(bcComps[bc], &cNc);CHKERRQ(ierr);}
177     if (bcComps && bcComps[bc]) {ierr = ISGetIndices(bcComps[bc], &comp);CHKERRQ(ierr);}
178     ierr = ISGetLocalSize(bcPoints[bc], &n);CHKERRQ(ierr);
179     ierr = ISGetIndices(bcPoints[bc], &idx);CHKERRQ(ierr);
180     for (i = 0; i < n; ++i) {
181       const PetscInt p = idx[i];
182       PetscInt       numConst;
183 
184       if (Nf) {
185         ierr = PetscSectionGetFieldDof(section, p, field, &numConst);CHKERRQ(ierr);
186       } else {
187         ierr = PetscSectionGetDof(section, p, &numConst);CHKERRQ(ierr);
188       }
189       /* If Nc <= 0, constrain every dof on the point */
190       if (cNc > 0) {
191         /* We assume that a point may have multiple "nodes", which are collections of Nc dofs,
192            and that those dofs are numbered n*Nc+c */
193         if (Nf) {
194           if (numConst % Nc) SETERRQ3(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Point %D has %D dof which is not divisible by %D field components", p, numConst, Nc);
195           numConst = (numConst/Nc) * cNc;
196         } else {
197           numConst = PetscMin(numConst, cNc);
198         }
199       }
200       if (Nf) {ierr = PetscSectionAddFieldConstraintDof(section, p, field, numConst);CHKERRQ(ierr);}
201       ierr = PetscSectionAddConstraintDof(section, p, numConst);CHKERRQ(ierr);
202     }
203     ierr = ISRestoreIndices(bcPoints[bc], &idx);CHKERRQ(ierr);
204     if (bcComps && bcComps[bc]) {ierr = ISRestoreIndices(bcComps[bc], &comp);CHKERRQ(ierr);}
205   }
206   ierr = DMPlexGetAnchors(dm, &aSec, NULL);CHKERRQ(ierr);
207   if (aSec) {
208     PetscInt aStart, aEnd, a;
209 
210     ierr = PetscSectionGetChart(aSec, &aStart, &aEnd);CHKERRQ(ierr);
211     for (a = aStart; a < aEnd; a++) {
212       PetscInt dof, f;
213 
214       ierr = PetscSectionGetDof(aSec, a, &dof);CHKERRQ(ierr);
215       if (dof) {
216         /* if there are point-to-point constraints, then all dofs are constrained */
217         ierr = PetscSectionGetDof(section, a, &dof);CHKERRQ(ierr);
218         ierr = PetscSectionSetConstraintDof(section, a, dof);CHKERRQ(ierr);
219         for (f = 0; f < Nf; f++) {
220           ierr = PetscSectionGetFieldDof(section, a, f, &dof);CHKERRQ(ierr);
221           ierr = PetscSectionSetFieldConstraintDof(section, a, f, dof);CHKERRQ(ierr);
222         }
223       }
224     }
225   }
226   PetscFunctionReturn(0);
227 }
228 
229 /* Set the constrained field indices on each point
230    If bcComps is NULL or the IS is NULL, constrain every dof on the point
231 */
232 static PetscErrorCode DMPlexCreateSectionBCIndicesField(DM dm, PetscInt numBC,const PetscInt bcField[], const IS bcComps[], const IS bcPoints[], PetscSection section)
233 {
234   PetscSection   aSec;
235   PetscInt      *indices;
236   PetscInt       Nf, cdof, maxDof = 0, pStart, pEnd, p, bc, f, d;
237   PetscErrorCode ierr;
238 
239   PetscFunctionBegin;
240   ierr = PetscSectionGetNumFields(section, &Nf);CHKERRQ(ierr);
241   if (!Nf) PetscFunctionReturn(0);
242   /* Initialize all field indices to -1 */
243   ierr = PetscSectionGetChart(section, &pStart, &pEnd);CHKERRQ(ierr);
244   for (p = pStart; p < pEnd; ++p) {ierr = PetscSectionGetConstraintDof(section, p, &cdof);CHKERRQ(ierr); maxDof = PetscMax(maxDof, cdof);}
245   ierr = PetscMalloc1(maxDof, &indices);CHKERRQ(ierr);
246   for (d = 0; d < maxDof; ++d) indices[d] = -1;
247   for (p = pStart; p < pEnd; ++p) for (f = 0; f < Nf; ++f) {ierr = PetscSectionSetFieldConstraintIndices(section, p, f, indices);CHKERRQ(ierr);}
248   /* Handle BC constraints */
249   for (bc = 0; bc < numBC; ++bc) {
250     const PetscInt  field = bcField[bc];
251     const PetscInt *comp, *idx;
252     PetscInt        Nc, cNc = -1, n, i;
253 
254     ierr = PetscSectionGetFieldComponents(section, field, &Nc);CHKERRQ(ierr);
255     if (bcComps && bcComps[bc]) {ierr = ISGetLocalSize(bcComps[bc], &cNc);CHKERRQ(ierr);}
256     if (bcComps && bcComps[bc]) {ierr = ISGetIndices(bcComps[bc], &comp);CHKERRQ(ierr);}
257     ierr = ISGetLocalSize(bcPoints[bc], &n);CHKERRQ(ierr);
258     ierr = ISGetIndices(bcPoints[bc], &idx);CHKERRQ(ierr);
259     for (i = 0; i < n; ++i) {
260       const PetscInt  p = idx[i];
261       const PetscInt *find;
262       PetscInt        fdof, fcdof, c, j;
263 
264       ierr = PetscSectionGetFieldDof(section, p, field, &fdof);CHKERRQ(ierr);
265       if (!fdof) continue;
266       if (cNc < 0) {
267         for (d = 0; d < fdof; ++d) indices[d] = d;
268         fcdof = fdof;
269       } else {
270         /* We assume that a point may have multiple "nodes", which are collections of Nc dofs,
271            and that those dofs are numbered n*Nc+c */
272         ierr = PetscSectionGetFieldConstraintDof(section, p, field, &fcdof);CHKERRQ(ierr);
273         ierr = PetscSectionGetFieldConstraintIndices(section, p, field, &find);CHKERRQ(ierr);
274         /* Get indices constrained by previous bcs */
275         for (d = 0; d < fcdof; ++d) {if (find[d] < 0) break; indices[d] = find[d];}
276         for (j = 0; j < fdof/Nc; ++j) for (c = 0; c < cNc; ++c) indices[d++] = j*Nc + comp[c];
277         ierr = PetscSortRemoveDupsInt(&d, indices);CHKERRQ(ierr);
278         for (c = d; c < fcdof; ++c) indices[c] = -1;
279         fcdof = d;
280       }
281       ierr = PetscSectionSetFieldConstraintDof(section, p, field, fcdof);CHKERRQ(ierr);
282       ierr = PetscSectionSetFieldConstraintIndices(section, p, field, indices);CHKERRQ(ierr);
283     }
284     if (bcComps && bcComps[bc]) {ierr = ISRestoreIndices(bcComps[bc], &comp);CHKERRQ(ierr);}
285     ierr = ISRestoreIndices(bcPoints[bc], &idx);CHKERRQ(ierr);
286   }
287   /* Handle anchors */
288   ierr = DMPlexGetAnchors(dm, &aSec, NULL);CHKERRQ(ierr);
289   if (aSec) {
290     PetscInt aStart, aEnd, a;
291 
292     for (d = 0; d < maxDof; ++d) indices[d] = d;
293     ierr = PetscSectionGetChart(aSec, &aStart, &aEnd);CHKERRQ(ierr);
294     for (a = aStart; a < aEnd; a++) {
295       PetscInt dof, f;
296 
297       ierr = PetscSectionGetDof(aSec, a, &dof);CHKERRQ(ierr);
298       if (dof) {
299         /* if there are point-to-point constraints, then all dofs are constrained */
300         for (f = 0; f < Nf; f++) {
301           ierr = PetscSectionSetFieldConstraintIndices(section, a, f, indices);CHKERRQ(ierr);
302         }
303       }
304     }
305   }
306   ierr = PetscFree(indices);CHKERRQ(ierr);
307   PetscFunctionReturn(0);
308 }
309 
310 /* Set the constrained indices on each point */
311 static PetscErrorCode DMPlexCreateSectionBCIndices(DM dm, PetscSection section)
312 {
313   PetscInt      *indices;
314   PetscInt       Nf, maxDof, pStart, pEnd, p, f, d;
315   PetscErrorCode ierr;
316 
317   PetscFunctionBegin;
318   ierr = PetscSectionGetNumFields(section, &Nf);CHKERRQ(ierr);
319   ierr = PetscSectionGetMaxDof(section, &maxDof);CHKERRQ(ierr);
320   ierr = PetscSectionGetChart(section, &pStart, &pEnd);CHKERRQ(ierr);
321   ierr = PetscMalloc1(maxDof, &indices);CHKERRQ(ierr);
322   for (d = 0; d < maxDof; ++d) indices[d] = -1;
323   for (p = pStart; p < pEnd; ++p) {
324     PetscInt cdof, d;
325 
326     ierr = PetscSectionGetConstraintDof(section, p, &cdof);CHKERRQ(ierr);
327     if (cdof) {
328       if (Nf) {
329         PetscInt numConst = 0, foff = 0;
330 
331         for (f = 0; f < Nf; ++f) {
332           const PetscInt *find;
333           PetscInt        fcdof, fdof;
334 
335           ierr = PetscSectionGetFieldDof(section, p, f, &fdof);CHKERRQ(ierr);
336           ierr = PetscSectionGetFieldConstraintDof(section, p, f, &fcdof);CHKERRQ(ierr);
337           /* Change constraint numbering from field component to local dof number */
338           ierr = PetscSectionGetFieldConstraintIndices(section, p, f, &find);CHKERRQ(ierr);
339           for (d = 0; d < fcdof; ++d) indices[numConst+d] = find[d] + foff;
340           numConst += fcdof;
341           foff     += fdof;
342         }
343         if (cdof != numConst) {ierr = PetscSectionSetConstraintDof(section, p, numConst);CHKERRQ(ierr);}
344       } else {
345         for (d = 0; d < cdof; ++d) indices[d] = d;
346       }
347       ierr = PetscSectionSetConstraintIndices(section, p, indices);CHKERRQ(ierr);
348     }
349   }
350   ierr = PetscFree(indices);CHKERRQ(ierr);
351   PetscFunctionReturn(0);
352 }
353 
354 /*@C
355   DMPlexCreateSection - Create a PetscSection based upon the dof layout specification provided.
356 
357   Not Collective
358 
359   Input Parameters:
360 + dm        - The DMPlex object
361 . label     - The label indicating the mesh support of each field, or NULL for the whole mesh
362 . numComp   - An array of size numFields that holds the number of components for each field
363 . numDof    - An array of size numFields*(dim+1) which holds the number of dof for each field on a mesh piece of dimension d
364 . numBC     - The number of boundary conditions
365 . bcField   - An array of size numBC giving the field number for each boundry condition
366 . bcComps   - [Optional] An array of size numBC giving an IS holding the field components to which each boundary condition applies
367 . bcPoints  - An array of size numBC giving an IS holding the Plex points to which each boundary condition applies
368 - perm      - Optional permutation of the chart, or NULL
369 
370   Output Parameter:
371 . section - The PetscSection object
372 
373   Notes:
374     numDof[f*(dim+1)+d] gives the number of dof for field f on points of dimension d. For instance, numDof[1] is the
375   number of dof for field 0 on each edge.
376 
377   The chart permutation is the same one set using PetscSectionSetPermutation()
378 
379   Level: developer
380 
381   TODO: How is this related to DMCreateLocalSection()
382 
383 .seealso: DMPlexCreate(), PetscSectionCreate(), PetscSectionSetPermutation()
384 @*/
385 PetscErrorCode DMPlexCreateSection(DM dm, DMLabel label[], const PetscInt numComp[],const PetscInt numDof[], PetscInt numBC, const PetscInt bcField[], const IS bcComps[], const IS bcPoints[], IS perm, PetscSection *section)
386 {
387   PetscSection   aSec;
388   PetscErrorCode ierr;
389 
390   PetscFunctionBegin;
391   ierr = DMPlexCreateSectionFields(dm, numComp, section);CHKERRQ(ierr);
392   ierr = DMPlexCreateSectionDof(dm, label, numDof, *section);CHKERRQ(ierr);
393   ierr = DMPlexCreateSectionBCDof(dm, numBC, bcField, bcComps, bcPoints, *section);CHKERRQ(ierr);
394   if (perm) {ierr = PetscSectionSetPermutation(*section, perm);CHKERRQ(ierr);}
395   ierr = PetscSectionSetFromOptions(*section);CHKERRQ(ierr);
396   ierr = PetscSectionSetUp(*section);CHKERRQ(ierr);
397   ierr = DMPlexGetAnchors(dm,&aSec,NULL);CHKERRQ(ierr);
398   if (numBC || aSec) {
399     ierr = DMPlexCreateSectionBCIndicesField(dm, numBC, bcField, bcComps, bcPoints, *section);CHKERRQ(ierr);
400     ierr = DMPlexCreateSectionBCIndices(dm, *section);CHKERRQ(ierr);
401   }
402   ierr = PetscSectionViewFromOptions(*section,NULL,"-section_view");CHKERRQ(ierr);
403   PetscFunctionReturn(0);
404 }
405 
406 PetscErrorCode DMCreateLocalSection_Plex(DM dm)
407 {
408   PetscDS        probBC;
409   PetscSection   section;
410   DMLabel       *labels;
411   IS            *bcPoints, *bcComps;
412   PetscBool     *isFE;
413   PetscInt      *bcFields, *numComp, *numDof;
414   PetscInt       depth, dim, numBd, numBC = 0, Nf, bd, bc = 0, f;
415   PetscInt       cStart, cEnd, cEndInterior;
416   PetscErrorCode ierr;
417 
418   PetscFunctionBegin;
419   ierr = DMGetNumFields(dm, &Nf);CHKERRQ(ierr);
420   /* FE and FV boundary conditions are handled slightly differently */
421   ierr = PetscMalloc1(Nf, &isFE);CHKERRQ(ierr);
422   for (f = 0; f < Nf; ++f) {
423     PetscObject  obj;
424     PetscClassId id;
425 
426     ierr = DMGetField(dm, f, NULL, &obj);CHKERRQ(ierr);
427     ierr = PetscObjectGetClassId(obj, &id);CHKERRQ(ierr);
428     if (id == PETSCFE_CLASSID)      {isFE[f] = PETSC_TRUE;}
429     else if (id == PETSCFV_CLASSID) {isFE[f] = PETSC_FALSE;}
430     else SETERRQ1(PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_WRONG, "Unknown discretization type for field %D", f);
431   }
432   /* Allocate boundary point storage for FEM boundaries */
433   ierr = DMPlexGetDepth(dm, &depth);CHKERRQ(ierr);
434   ierr = DMGetDimension(dm, &dim);CHKERRQ(ierr);
435   ierr = DMPlexGetHeightStratum(dm, 0, &cStart, &cEnd);CHKERRQ(ierr);
436   ierr = DMPlexGetGhostCellStratum(dm, &cEndInterior, NULL);CHKERRQ(ierr);
437   ierr = DMGetDS(dm, &probBC);CHKERRQ(ierr);
438   ierr = PetscDSGetNumBoundary(probBC, &numBd);CHKERRQ(ierr);
439   if (!Nf && numBd) SETERRQ(PetscObjectComm((PetscObject)dm), PETSC_ERR_PLIB, "number of fields is zero and number of boundary conditions is nonzero (this should never happen)");
440   for (bd = 0; bd < numBd; ++bd) {
441     PetscInt                field;
442     DMBoundaryConditionType type;
443     const char             *labelName;
444     DMLabel                 label;
445 
446     ierr = PetscDSGetBoundary(probBC, bd, &type, NULL, &labelName, &field, NULL, NULL, NULL, NULL, NULL, NULL);CHKERRQ(ierr);
447     ierr = DMGetLabel(dm,labelName,&label);CHKERRQ(ierr);
448     if (label && isFE[field] && (type & DM_BC_ESSENTIAL)) ++numBC;
449   }
450   /* Add ghost cell boundaries for FVM */
451   for (f = 0; f < Nf; ++f) if (!isFE[f] && cEndInterior >= 0) ++numBC;
452   ierr = PetscCalloc3(numBC,&bcFields,numBC,&bcPoints,numBC,&bcComps);CHKERRQ(ierr);
453   /* Constrain ghost cells for FV */
454   for (f = 0; f < Nf; ++f) {
455     PetscInt *newidx, c;
456 
457     if (isFE[f] || cEndInterior < 0) continue;
458     ierr = PetscMalloc1(cEnd-cEndInterior,&newidx);CHKERRQ(ierr);
459     for (c = cEndInterior; c < cEnd; ++c) newidx[c-cEndInterior] = c;
460     bcFields[bc] = f;
461     ierr = ISCreateGeneral(PETSC_COMM_SELF, cEnd-cEndInterior, newidx, PETSC_OWN_POINTER, &bcPoints[bc++]);CHKERRQ(ierr);
462   }
463   /* Handle FEM Dirichlet boundaries */
464   for (bd = 0; bd < numBd; ++bd) {
465     const char             *bdLabel;
466     DMLabel                 label;
467     const PetscInt         *comps;
468     const PetscInt         *values;
469     PetscInt                bd2, field, numComps, numValues;
470     DMBoundaryConditionType type;
471     PetscBool               duplicate = PETSC_FALSE;
472 
473     ierr = PetscDSGetBoundary(probBC, bd, &type, NULL, &bdLabel, &field, &numComps, &comps, NULL, &numValues, &values, NULL);CHKERRQ(ierr);
474     ierr = DMGetLabel(dm, bdLabel, &label);CHKERRQ(ierr);
475     if (!isFE[field] || !label) continue;
476     /* Only want to modify label once */
477     for (bd2 = 0; bd2 < bd; ++bd2) {
478       const char *bdname;
479       ierr = PetscDSGetBoundary(probBC, bd2, NULL, NULL, &bdname, NULL, NULL, NULL, NULL, NULL, NULL, NULL);CHKERRQ(ierr);
480       ierr = PetscStrcmp(bdname, bdLabel, &duplicate);CHKERRQ(ierr);
481       if (duplicate) break;
482     }
483     if (!duplicate && (isFE[field])) {
484       /* don't complete cells, which are just present to give orientation to the boundary */
485       ierr = DMPlexLabelComplete(dm, label);CHKERRQ(ierr);
486     }
487     /* Filter out cells, if you actually want to constrain cells you need to do things by hand right now */
488     if (type & DM_BC_ESSENTIAL) {
489       PetscInt       *newidx;
490       PetscInt        n, newn = 0, p, v;
491 
492       bcFields[bc] = field;
493       if (numComps) {ierr = ISCreateGeneral(PETSC_COMM_SELF, numComps, comps, PETSC_COPY_VALUES, &bcComps[bc]);CHKERRQ(ierr);}
494       for (v = 0; v < numValues; ++v) {
495         IS              tmp;
496         const PetscInt *idx;
497 
498         ierr = DMGetStratumIS(dm, bdLabel, values[v], &tmp);CHKERRQ(ierr);
499         if (!tmp) continue;
500         ierr = ISGetLocalSize(tmp, &n);CHKERRQ(ierr);
501         ierr = ISGetIndices(tmp, &idx);CHKERRQ(ierr);
502         if (isFE[field]) {
503           for (p = 0; p < n; ++p) if ((idx[p] < cStart) || (idx[p] >= cEnd)) ++newn;
504         } else {
505           for (p = 0; p < n; ++p) if ((idx[p] >= cStart) || (idx[p] < cEnd)) ++newn;
506         }
507         ierr = ISRestoreIndices(tmp, &idx);CHKERRQ(ierr);
508         ierr = ISDestroy(&tmp);CHKERRQ(ierr);
509       }
510       ierr = PetscMalloc1(newn,&newidx);CHKERRQ(ierr);
511       newn = 0;
512       for (v = 0; v < numValues; ++v) {
513         IS              tmp;
514         const PetscInt *idx;
515 
516         ierr = DMGetStratumIS(dm, bdLabel, values[v], &tmp);CHKERRQ(ierr);
517         if (!tmp) continue;
518         ierr = ISGetLocalSize(tmp, &n);CHKERRQ(ierr);
519         ierr = ISGetIndices(tmp, &idx);CHKERRQ(ierr);
520         if (isFE[field]) {
521           for (p = 0; p < n; ++p) if ((idx[p] < cStart) || (idx[p] >= cEnd)) newidx[newn++] = idx[p];
522         } else {
523           for (p = 0; p < n; ++p) if ((idx[p] >= cStart) || (idx[p] < cEnd)) newidx[newn++] = idx[p];
524         }
525         ierr = ISRestoreIndices(tmp, &idx);CHKERRQ(ierr);
526         ierr = ISDestroy(&tmp);CHKERRQ(ierr);
527       }
528       ierr = ISCreateGeneral(PETSC_COMM_SELF, newn, newidx, PETSC_OWN_POINTER, &bcPoints[bc++]);CHKERRQ(ierr);
529     }
530   }
531   /* Handle discretization */
532   ierr = PetscCalloc3(Nf,&labels,Nf,&numComp,Nf*(dim+1),&numDof);CHKERRQ(ierr);
533   for (f = 0; f < Nf; ++f) {
534     labels[f] = dm->fields[f].label;
535     if (isFE[f]) {
536       PetscFE         fe = (PetscFE) dm->fields[f].disc;
537       const PetscInt *numFieldDof;
538       PetscInt        fedim, d;
539 
540       ierr = PetscFEGetNumComponents(fe, &numComp[f]);CHKERRQ(ierr);
541       ierr = PetscFEGetNumDof(fe, &numFieldDof);CHKERRQ(ierr);
542       ierr = PetscFEGetSpatialDimension(fe, &fedim);CHKERRQ(ierr);
543       for (d = 0; d < PetscMin(dim, fedim)+1; ++d) numDof[f*(dim+1)+d] = numFieldDof[d];
544     } else {
545       PetscFV fv = (PetscFV) dm->fields[f].disc;
546 
547       ierr = PetscFVGetNumComponents(fv, &numComp[f]);CHKERRQ(ierr);
548       numDof[f*(dim+1)+dim] = numComp[f];
549     }
550   }
551   for (f = 0; f < Nf; ++f) {
552     PetscInt d;
553     for (d = 1; d < dim; ++d) {
554       if ((numDof[f*(dim+1)+d] > 0) && (depth < dim)) SETERRQ(PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_WRONG, "Mesh must be interpolated when unknowns are specified on edges or faces.");
555     }
556   }
557   ierr = DMPlexCreateSection(dm, labels, numComp, numDof, numBC, bcFields, bcComps, bcPoints, NULL, &section);CHKERRQ(ierr);
558   for (f = 0; f < Nf; ++f) {
559     PetscFE     fe;
560     const char *name;
561 
562     if (isFE[f]) {
563       ierr = DMGetField(dm, f, NULL, (PetscObject *) &fe);CHKERRQ(ierr);
564       ierr = PetscObjectGetName((PetscObject) fe, &name);CHKERRQ(ierr);
565       ierr = PetscSectionSetFieldName(section, f, name);CHKERRQ(ierr);
566     }
567   }
568   ierr = DMSetLocalSection(dm, section);CHKERRQ(ierr);
569   ierr = PetscSectionDestroy(&section);CHKERRQ(ierr);
570   for (bc = 0; bc < numBC; ++bc) {ierr = ISDestroy(&bcPoints[bc]);CHKERRQ(ierr);ierr = ISDestroy(&bcComps[bc]);CHKERRQ(ierr);}
571   ierr = PetscFree3(bcFields,bcPoints,bcComps);CHKERRQ(ierr);
572   ierr = PetscFree3(labels,numComp,numDof);CHKERRQ(ierr);
573   ierr = PetscFree(isFE);CHKERRQ(ierr);
574   PetscFunctionReturn(0);
575 }
576