Actual source code: section.c

  1: /*
  2:    This file contains routines for basic section object implementation.
  3: */

  5: #include <petsc/private/sectionimpl.h>
  6: #include <petscsf.h>

  8: PetscClassId PETSC_SECTION_CLASSID;

 10: /*@
 11:   PetscSectionCreate - Allocates a `PetscSection` and sets the map contents to the default.

 13:   Collective

 15:   Input Parameters:
 16: + comm - the MPI communicator
 17: - s    - pointer to the section

 19:   Level: beginner

 21:   Notes:
 22:   Typical calling sequence
 23: .vb
 24:        PetscSectionCreate(MPI_Comm,PetscSection *);!
 25:        PetscSectionSetNumFields(PetscSection, numFields);
 26:        PetscSectionSetChart(PetscSection,low,high);
 27:        PetscSectionSetDof(PetscSection,point,numdof);
 28:        PetscSectionSetUp(PetscSection);
 29:        PetscSectionGetOffset(PetscSection,point,PetscInt *);
 30:        PetscSectionDestroy(PetscSection);
 31: .ve

 33:   The `PetscSection` object and methods are intended to be used in the PETSc `Vec` and `Mat` implementations. The indices returned by the `PetscSection` are appropriate for the kind of `Vec` it is associated with. For example, if the vector being indexed is a local vector, we call the section a local section. If the section indexes a global vector, we call it a global section. For parallel vectors, like global vectors, we use negative indices to indicate dofs owned by other processes.

 35: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionSetChart()`, `PetscSectionDestroy()`, `PetscSectionCreateGlobalSection()`
 36: @*/
 37: PetscErrorCode PetscSectionCreate(MPI_Comm comm, PetscSection *s)
 38: {
 39:   PetscFunctionBegin;
 40:   PetscAssertPointer(s, 2);
 41:   PetscCall(ISInitializePackage());

 43:   PetscCall(PetscHeaderCreate(*s, PETSC_SECTION_CLASSID, "PetscSection", "Section", "IS", comm, PetscSectionDestroy, PetscSectionView));
 44:   (*s)->pStart              = -1;
 45:   (*s)->pEnd                = -1;
 46:   (*s)->perm                = NULL;
 47:   (*s)->pointMajor          = PETSC_TRUE;
 48:   (*s)->includesConstraints = PETSC_TRUE;
 49:   (*s)->atlasDof            = NULL;
 50:   (*s)->atlasOff            = NULL;
 51:   (*s)->bc                  = NULL;
 52:   (*s)->bcIndices           = NULL;
 53:   (*s)->setup               = PETSC_FALSE;
 54:   (*s)->numFields           = 0;
 55:   (*s)->fieldNames          = NULL;
 56:   (*s)->field               = NULL;
 57:   (*s)->useFieldOff         = PETSC_FALSE;
 58:   (*s)->compNames           = NULL;
 59:   (*s)->clObj               = NULL;
 60:   (*s)->clHash              = NULL;
 61:   (*s)->clSection           = NULL;
 62:   (*s)->clPoints            = NULL;
 63:   PetscCall(PetscSectionInvalidateMaxDof_Internal(*s));
 64:   PetscFunctionReturn(PETSC_SUCCESS);
 65: }

 67: /*@
 68:   PetscSectionCopy - Creates a shallow (if possible) copy of the `PetscSection`

 70:   Collective

 72:   Input Parameter:
 73: . section - the `PetscSection`

 75:   Output Parameter:
 76: . newSection - the copy

 78:   Level: intermediate

 80:   Developer Notes:
 81:   What exactly does shallow mean in this context?

 83: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionCreate()`, `PetscSectionDestroy()`
 84: @*/
 85: PetscErrorCode PetscSectionCopy(PetscSection section, PetscSection newSection)
 86: {
 87:   PetscFunctionBegin;
 90:   PetscCall(PetscSectionCopy_Internal(section, newSection, NULL));
 91:   PetscFunctionReturn(PETSC_SUCCESS);
 92: }

 94: PetscErrorCode PetscSectionCopy_Internal(PetscSection section, PetscSection newSection, PetscBT constrained_dofs)
 95: {
 96:   PetscSectionSym sym;
 97:   IS              perm;
 98:   PetscInt        numFields, f, c, pStart, pEnd, p;

100:   PetscFunctionBegin;
103:   PetscCall(PetscSectionReset(newSection));
104:   PetscCall(PetscSectionGetNumFields(section, &numFields));
105:   if (numFields) PetscCall(PetscSectionSetNumFields(newSection, numFields));
106:   for (f = 0; f < numFields; ++f) {
107:     const char *fieldName = NULL, *compName = NULL;
108:     PetscInt    numComp = 0;

110:     PetscCall(PetscSectionGetFieldName(section, f, &fieldName));
111:     PetscCall(PetscSectionSetFieldName(newSection, f, fieldName));
112:     PetscCall(PetscSectionGetFieldComponents(section, f, &numComp));
113:     PetscCall(PetscSectionSetFieldComponents(newSection, f, numComp));
114:     for (c = 0; c < numComp; ++c) {
115:       PetscCall(PetscSectionGetComponentName(section, f, c, &compName));
116:       PetscCall(PetscSectionSetComponentName(newSection, f, c, compName));
117:     }
118:     PetscCall(PetscSectionGetFieldSym(section, f, &sym));
119:     PetscCall(PetscSectionSetFieldSym(newSection, f, sym));
120:   }
121:   PetscCall(PetscSectionGetChart(section, &pStart, &pEnd));
122:   PetscCall(PetscSectionSetChart(newSection, pStart, pEnd));
123:   PetscCall(PetscSectionGetPermutation(section, &perm));
124:   PetscCall(PetscSectionSetPermutation(newSection, perm));
125:   PetscCall(PetscSectionGetSym(section, &sym));
126:   PetscCall(PetscSectionSetSym(newSection, sym));
127:   for (p = pStart; p < pEnd; ++p) {
128:     PetscInt  dof, cdof, fcdof = 0;
129:     PetscBool force_constrained = (PetscBool)(constrained_dofs && PetscBTLookup(constrained_dofs, p - pStart));

131:     PetscCall(PetscSectionGetDof(section, p, &dof));
132:     PetscCall(PetscSectionSetDof(newSection, p, dof));
133:     if (force_constrained) cdof = dof;
134:     else PetscCall(PetscSectionGetConstraintDof(section, p, &cdof));
135:     if (cdof) PetscCall(PetscSectionSetConstraintDof(newSection, p, cdof));
136:     for (f = 0; f < numFields; ++f) {
137:       PetscCall(PetscSectionGetFieldDof(section, p, f, &dof));
138:       PetscCall(PetscSectionSetFieldDof(newSection, p, f, dof));
139:       if (cdof) {
140:         if (force_constrained) fcdof = dof;
141:         else PetscCall(PetscSectionGetFieldConstraintDof(section, p, f, &fcdof));
142:         if (fcdof) PetscCall(PetscSectionSetFieldConstraintDof(newSection, p, f, fcdof));
143:       }
144:     }
145:   }
146:   PetscCall(PetscSectionSetUp(newSection));
147:   for (p = pStart; p < pEnd; ++p) {
148:     PetscInt        off, cdof, fcdof = 0;
149:     const PetscInt *cInd;
150:     PetscBool       force_constrained = (PetscBool)(constrained_dofs && PetscBTLookup(constrained_dofs, p - pStart));

152:     /* Must set offsets in case they do not agree with the prefix sums */
153:     PetscCall(PetscSectionGetOffset(section, p, &off));
154:     PetscCall(PetscSectionSetOffset(newSection, p, off));
155:     PetscCall(PetscSectionGetConstraintDof(newSection, p, &cdof));
156:     if (cdof) {
157:       if (force_constrained) cInd = NULL;
158:       else PetscCall(PetscSectionGetConstraintIndices(section, p, &cInd));
159:       PetscCall(PetscSectionSetConstraintIndices(newSection, p, cInd));
160:       for (f = 0; f < numFields; ++f) {
161:         PetscCall(PetscSectionGetFieldOffset(section, p, f, &off));
162:         PetscCall(PetscSectionSetFieldOffset(newSection, p, f, off));
163:         PetscCall(PetscSectionGetFieldConstraintDof(newSection, p, f, &fcdof));
164:         if (fcdof) {
165:           if (force_constrained) cInd = NULL;
166:           else PetscCall(PetscSectionGetFieldConstraintIndices(section, p, f, &cInd));
167:           PetscCall(PetscSectionSetFieldConstraintIndices(newSection, p, f, cInd));
168:         }
169:       }
170:     }
171:   }
172:   PetscFunctionReturn(PETSC_SUCCESS);
173: }

175: /*@
176:   PetscSectionClone - Creates a shallow (if possible) copy of the `PetscSection`

178:   Collective

180:   Input Parameter:
181: . section - the `PetscSection`

183:   Output Parameter:
184: . newSection - the copy

186:   Level: beginner

188:   Developer Notes:
189:   With standard PETSc terminology this should be called `PetscSectionDuplicate()`

191: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionCreate()`, `PetscSectionDestroy()`, `PetscSectionCopy()`
192: @*/
193: PetscErrorCode PetscSectionClone(PetscSection section, PetscSection *newSection)
194: {
195:   PetscFunctionBegin;
197:   PetscAssertPointer(newSection, 2);
198:   PetscCall(PetscSectionCreate(PetscObjectComm((PetscObject)section), newSection));
199:   PetscCall(PetscSectionCopy(section, *newSection));
200:   PetscFunctionReturn(PETSC_SUCCESS);
201: }

203: /*@
204:   PetscSectionSetFromOptions - sets parameters in a `PetscSection` from the options database

206:   Collective

208:   Input Parameter:
209: . s - the `PetscSection`

211:   Options Database Key:
212: . -petscsection_point_major - `PETSC_TRUE` for point-major order

214:   Level: intermediate

216: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionCreate()`, `PetscSectionDestroy()`
217: @*/
218: PetscErrorCode PetscSectionSetFromOptions(PetscSection s)
219: {
220:   PetscFunctionBegin;
222:   PetscObjectOptionsBegin((PetscObject)s);
223:   PetscCall(PetscOptionsBool("-petscsection_point_major", "The for ordering, either point major or field major", "PetscSectionSetPointMajor", s->pointMajor, &s->pointMajor, NULL));
224:   /* process any options handlers added with PetscObjectAddOptionsHandler() */
225:   PetscCall(PetscObjectProcessOptionsHandlers((PetscObject)s, PetscOptionsObject));
226:   PetscOptionsEnd();
227:   PetscCall(PetscObjectViewFromOptions((PetscObject)s, NULL, "-petscsection_view"));
228:   PetscFunctionReturn(PETSC_SUCCESS);
229: }

231: /*@
232:   PetscSectionCompare - Compares two sections

234:   Collective

236:   Input Parameters:
237: + s1 - the first `PetscSection`
238: - s2 - the second `PetscSection`

240:   Output Parameter:
241: . congruent - `PETSC_TRUE` if the two sections are congruent, `PETSC_FALSE` otherwise

243:   Level: intermediate

245:   Note:
246:   Field names are disregarded.

248: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionCreate()`, `PetscSectionCopy()`, `PetscSectionClone()`
249: @*/
250: PetscErrorCode PetscSectionCompare(PetscSection s1, PetscSection s2, PetscBool *congruent)
251: {
252:   PetscInt        pStart, pEnd, nfields, ncdof, nfcdof, p, f, n1, n2;
253:   const PetscInt *idx1, *idx2;
254:   IS              perm1, perm2;
255:   PetscBool       flg;
256:   PetscMPIInt     mflg;

258:   PetscFunctionBegin;
261:   PetscAssertPointer(congruent, 3);
262:   flg = PETSC_FALSE;

264:   PetscCallMPI(MPI_Comm_compare(PetscObjectComm((PetscObject)s1), PetscObjectComm((PetscObject)s2), &mflg));
265:   if (mflg != MPI_CONGRUENT && mflg != MPI_IDENT) {
266:     *congruent = PETSC_FALSE;
267:     PetscFunctionReturn(PETSC_SUCCESS);
268:   }

270:   PetscCall(PetscSectionGetChart(s1, &pStart, &pEnd));
271:   PetscCall(PetscSectionGetChart(s2, &n1, &n2));
272:   if (pStart != n1 || pEnd != n2) goto not_congruent;

274:   PetscCall(PetscSectionGetPermutation(s1, &perm1));
275:   PetscCall(PetscSectionGetPermutation(s2, &perm2));
276:   if (perm1 && perm2) {
277:     PetscCall(ISEqual(perm1, perm2, congruent));
278:     if (!*congruent) goto not_congruent;
279:   } else if (perm1 != perm2) goto not_congruent;

281:   for (p = pStart; p < pEnd; ++p) {
282:     PetscCall(PetscSectionGetOffset(s1, p, &n1));
283:     PetscCall(PetscSectionGetOffset(s2, p, &n2));
284:     if (n1 != n2) goto not_congruent;

286:     PetscCall(PetscSectionGetDof(s1, p, &n1));
287:     PetscCall(PetscSectionGetDof(s2, p, &n2));
288:     if (n1 != n2) goto not_congruent;

290:     PetscCall(PetscSectionGetConstraintDof(s1, p, &ncdof));
291:     PetscCall(PetscSectionGetConstraintDof(s2, p, &n2));
292:     if (ncdof != n2) goto not_congruent;

294:     PetscCall(PetscSectionGetConstraintIndices(s1, p, &idx1));
295:     PetscCall(PetscSectionGetConstraintIndices(s2, p, &idx2));
296:     PetscCall(PetscArraycmp(idx1, idx2, ncdof, congruent));
297:     if (!*congruent) goto not_congruent;
298:   }

300:   PetscCall(PetscSectionGetNumFields(s1, &nfields));
301:   PetscCall(PetscSectionGetNumFields(s2, &n2));
302:   if (nfields != n2) goto not_congruent;

304:   for (f = 0; f < nfields; ++f) {
305:     PetscCall(PetscSectionGetFieldComponents(s1, f, &n1));
306:     PetscCall(PetscSectionGetFieldComponents(s2, f, &n2));
307:     if (n1 != n2) goto not_congruent;

309:     for (p = pStart; p < pEnd; ++p) {
310:       PetscCall(PetscSectionGetFieldOffset(s1, p, f, &n1));
311:       PetscCall(PetscSectionGetFieldOffset(s2, p, f, &n2));
312:       if (n1 != n2) goto not_congruent;

314:       PetscCall(PetscSectionGetFieldDof(s1, p, f, &n1));
315:       PetscCall(PetscSectionGetFieldDof(s2, p, f, &n2));
316:       if (n1 != n2) goto not_congruent;

318:       PetscCall(PetscSectionGetFieldConstraintDof(s1, p, f, &nfcdof));
319:       PetscCall(PetscSectionGetFieldConstraintDof(s2, p, f, &n2));
320:       if (nfcdof != n2) goto not_congruent;

322:       PetscCall(PetscSectionGetFieldConstraintIndices(s1, p, f, &idx1));
323:       PetscCall(PetscSectionGetFieldConstraintIndices(s2, p, f, &idx2));
324:       PetscCall(PetscArraycmp(idx1, idx2, nfcdof, congruent));
325:       if (!*congruent) goto not_congruent;
326:     }
327:   }

329:   flg = PETSC_TRUE;
330: not_congruent:
331:   PetscCallMPI(MPIU_Allreduce(&flg, congruent, 1, MPIU_BOOL, MPI_LAND, PetscObjectComm((PetscObject)s1)));
332:   PetscFunctionReturn(PETSC_SUCCESS);
333: }

335: /*@
336:   PetscSectionGetNumFields - Returns the number of fields in a `PetscSection`, or 0 if no fields were defined.

338:   Not Collective

340:   Input Parameter:
341: . s - the `PetscSection`

343:   Output Parameter:
344: . numFields - the number of fields defined, or 0 if none were defined

346:   Level: intermediate

348: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionSetNumFields()`
349: @*/
350: PetscErrorCode PetscSectionGetNumFields(PetscSection s, PetscInt *numFields)
351: {
352:   PetscFunctionBegin;
354:   PetscAssertPointer(numFields, 2);
355:   *numFields = s->numFields;
356:   PetscFunctionReturn(PETSC_SUCCESS);
357: }

359: /*@
360:   PetscSectionSetNumFields - Sets the number of fields in a `PetscSection`

362:   Not Collective

364:   Input Parameters:
365: + s         - the `PetscSection`
366: - numFields - the number of fields

368:   Level: intermediate

370:   Notes:
371:   Calling this destroys all the information in the `PetscSection` including the chart.

373:   You must call `PetscSectionSetChart()` after calling this.

375: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionGetNumFields()`, `PetscSectionSetChart()`, `PetscSectionReset()`
376: @*/
377: PetscErrorCode PetscSectionSetNumFields(PetscSection s, PetscInt numFields)
378: {
379:   PetscInt f;

381:   PetscFunctionBegin;
383:   PetscCheck(numFields > 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "The number of fields %" PetscInt_FMT " must be positive", numFields);
384:   PetscCall(PetscSectionReset(s));

386:   s->numFields = numFields;
387:   PetscCall(PetscMalloc1(s->numFields, &s->numFieldComponents));
388:   PetscCall(PetscMalloc1(s->numFields, &s->fieldNames));
389:   PetscCall(PetscMalloc1(s->numFields, &s->compNames));
390:   PetscCall(PetscMalloc1(s->numFields, &s->field));
391:   for (f = 0; f < s->numFields; ++f) {
392:     char name[64];

394:     s->numFieldComponents[f] = 1;

396:     PetscCall(PetscSectionCreate(PetscObjectComm((PetscObject)s), &s->field[f]));
397:     PetscCall(PetscSNPrintf(name, 64, "Field_%" PetscInt_FMT, f));
398:     PetscCall(PetscStrallocpy(name, (char **)&s->fieldNames[f]));
399:     PetscCall(PetscSNPrintf(name, 64, "Component_0"));
400:     PetscCall(PetscMalloc1(s->numFieldComponents[f], &s->compNames[f]));
401:     PetscCall(PetscStrallocpy(name, (char **)&s->compNames[f][0]));
402:   }
403:   PetscFunctionReturn(PETSC_SUCCESS);
404: }

406: /*@
407:   PetscSectionGetFieldName - Returns the name of a field in the `PetscSection`

409:   Not Collective

411:   Input Parameters:
412: + s     - the `PetscSection`
413: - field - the field number

415:   Output Parameter:
416: . fieldName - the field name

418:   Level: intermediate

420:   Note:
421:   Will error if the field number is out of range

423: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionSetFieldName()`, `PetscSectionSetNumFields()`, `PetscSectionGetNumFields()`
424: @*/
425: PetscErrorCode PetscSectionGetFieldName(PetscSection s, PetscInt field, const char *fieldName[])
426: {
427:   PetscFunctionBegin;
429:   PetscAssertPointer(fieldName, 3);
430:   PetscSectionCheckValidField(field, s->numFields);
431:   *fieldName = s->fieldNames[field];
432:   PetscFunctionReturn(PETSC_SUCCESS);
433: }

435: /*@
436:   PetscSectionSetFieldName - Sets the name of a field in the `PetscSection`

438:   Not Collective

440:   Input Parameters:
441: + s         - the `PetscSection`
442: . field     - the field number
443: - fieldName - the field name

445:   Level: intermediate

447:   Note:
448:   Will error if the field number is out of range

450: .seealso: [PetscSection](sec_petscsection), `PetscSectionGetFieldName()`, `PetscSectionSetNumFields()`, `PetscSectionGetNumFields()`
451: @*/
452: PetscErrorCode PetscSectionSetFieldName(PetscSection s, PetscInt field, const char fieldName[])
453: {
454:   PetscFunctionBegin;
456:   if (fieldName) PetscAssertPointer(fieldName, 3);
457:   PetscSectionCheckValidField(field, s->numFields);
458:   PetscCall(PetscFree(s->fieldNames[field]));
459:   PetscCall(PetscStrallocpy(fieldName, (char **)&s->fieldNames[field]));
460:   PetscFunctionReturn(PETSC_SUCCESS);
461: }

463: /*@
464:   PetscSectionGetComponentName - Gets the name of a field component in the `PetscSection`

466:   Not Collective

468:   Input Parameters:
469: + s     - the `PetscSection`
470: . field - the field number
471: - comp  - the component number

473:   Output Parameter:
474: . compName - the component name

476:   Level: intermediate

478:   Note:
479:   Will error if the field or component number do not exist

481:   Developer Notes:
482:   The function name should have Field in it since they are field components.

484: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionGetFieldName()`, `PetscSectionSetNumFields()`, `PetscSectionGetNumFields()`,
485:           `PetscSectionSetComponentName()`, `PetscSectionSetFieldName()`, `PetscSectionGetFieldComponents()`, `PetscSectionSetFieldComponents()`
486: @*/
487: PetscErrorCode PetscSectionGetComponentName(PetscSection s, PetscInt field, PetscInt comp, const char *compName[])
488: {
489:   PetscFunctionBegin;
491:   PetscAssertPointer(compName, 4);
492:   PetscSectionCheckValidField(field, s->numFields);
493:   PetscSectionCheckValidFieldComponent(comp, s->numFieldComponents[field]);
494:   *compName = s->compNames[field][comp];
495:   PetscFunctionReturn(PETSC_SUCCESS);
496: }

498: /*@
499:   PetscSectionSetComponentName - Sets the name of a field component in the `PetscSection`

501:   Not Collective

503:   Input Parameters:
504: + s        - the `PetscSection`
505: . field    - the field number
506: . comp     - the component number
507: - compName - the component name

509:   Level: advanced

511:   Note:
512:   Will error if the field or component number do not exist

514:   Developer Notes:
515:   The function name should have Field in it since they are field components.

517: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionGetComponentName()`, `PetscSectionSetNumFields()`, `PetscSectionGetNumFields()`,
518:           `PetscSectionSetFieldName()`, `PetscSectionGetFieldComponents()`, `PetscSectionSetFieldComponents()`
519: @*/
520: PetscErrorCode PetscSectionSetComponentName(PetscSection s, PetscInt field, PetscInt comp, const char compName[])
521: {
522:   PetscFunctionBegin;
524:   if (compName) PetscAssertPointer(compName, 4);
525:   PetscSectionCheckValidField(field, s->numFields);
526:   PetscSectionCheckValidFieldComponent(comp, s->numFieldComponents[field]);
527:   PetscCall(PetscFree(s->compNames[field][comp]));
528:   PetscCall(PetscStrallocpy(compName, (char **)&s->compNames[field][comp]));
529:   PetscFunctionReturn(PETSC_SUCCESS);
530: }

532: /*@
533:   PetscSectionGetFieldComponents - Returns the number of field components for the given field.

535:   Not Collective

537:   Input Parameters:
538: + s     - the `PetscSection`
539: - field - the field number

541:   Output Parameter:
542: . numComp - the number of field components

544:   Level: advanced

546:   Developer Notes:
547:   This function is misnamed. There is a Num in `PetscSectionGetNumFields()` but not in this name

549: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionSetFieldComponents()`, `PetscSectionGetNumFields()`,
550:           `PetscSectionSetComponentName()`, `PetscSectionGetComponentName()`
551: @*/
552: PetscErrorCode PetscSectionGetFieldComponents(PetscSection s, PetscInt field, PetscInt *numComp)
553: {
554:   PetscFunctionBegin;
556:   PetscAssertPointer(numComp, 3);
557:   PetscSectionCheckValidField(field, s->numFields);
558:   *numComp = s->numFieldComponents[field];
559:   PetscFunctionReturn(PETSC_SUCCESS);
560: }

562: /*@
563:   PetscSectionSetFieldComponents - Sets the number of field components for the given field.

565:   Not Collective

567:   Input Parameters:
568: + s       - the `PetscSection`
569: . field   - the field number
570: - numComp - the number of field components

572:   Level: advanced

574:   Note:
575:   This number can be different than the values set with `PetscSectionSetFieldDof()`. It can be used to indicate the number of
576:   components in the field of the underlying physical model which may be different than the number of degrees of freedom needed
577:   at a point in a discretization. For example, if in three dimensions the field is velocity, it will have 3 components, u, v, and w but
578:   an face based model for velocity (where the velocity normal to the face is stored) there is only 1 dof for each face point.

580:   The value set with this function are not needed or used in `PetscSectionSetUp()`.

582:   Developer Notes:
583:   This function is misnamed. There is a Num in `PetscSectionSetNumFields()` but not in this name

585: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionGetFieldComponents()`, `PetscSectionSetComponentName()`,
586:           `PetscSectionGetComponentName()`, `PetscSectionGetNumFields()`
587: @*/
588: PetscErrorCode PetscSectionSetFieldComponents(PetscSection s, PetscInt field, PetscInt numComp)
589: {
590:   PetscInt c;

592:   PetscFunctionBegin;
594:   PetscSectionCheckValidField(field, s->numFields);
595:   if (s->compNames) {
596:     for (c = 0; c < s->numFieldComponents[field]; ++c) PetscCall(PetscFree(s->compNames[field][c]));
597:     PetscCall(PetscFree(s->compNames[field]));
598:   }

600:   s->numFieldComponents[field] = numComp;
601:   if (numComp) {
602:     PetscCall(PetscMalloc1(numComp, (char ***)&s->compNames[field]));
603:     for (c = 0; c < numComp; ++c) {
604:       char name[64];

606:       PetscCall(PetscSNPrintf(name, 64, "%" PetscInt_FMT, c));
607:       PetscCall(PetscStrallocpy(name, (char **)&s->compNames[field][c]));
608:     }
609:   }
610:   PetscFunctionReturn(PETSC_SUCCESS);
611: }

613: /*@
614:   PetscSectionGetChart - Returns the range [`pStart`, `pEnd`) in which points (indices) lie for this `PetscSection` on this MPI process

616:   Not Collective

618:   Input Parameter:
619: . s - the `PetscSection`

621:   Output Parameters:
622: + pStart - the first point
623: - pEnd   - one past the last point

625:   Level: intermediate

627: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionSetChart()`, `PetscSectionCreate()`
628: @*/
629: PetscErrorCode PetscSectionGetChart(PetscSection s, PetscInt *pStart, PetscInt *pEnd)
630: {
631:   PetscFunctionBegin;
633:   if (pStart) *pStart = s->pStart;
634:   if (pEnd) *pEnd = s->pEnd;
635:   PetscFunctionReturn(PETSC_SUCCESS);
636: }

638: /*@
639:   PetscSectionSetChart - Sets the range [`pStart`, `pEnd`) in which points (indices) lie for this `PetscSection` on this MPI process

641:   Not Collective

643:   Input Parameters:
644: + s      - the `PetscSection`
645: . pStart - the first point
646: - pEnd   - one past the last point, `pStart` $ \le $ `pEnd`

648:   Level: intermediate

650:   Notes:
651:   The charts on different MPI processes may (and often do) overlap

653:   If you intend to use `PetscSectionSetNumFields()` it must be called before this call.

655:   The chart for all fields created with `PetscSectionSetNumFields()` is the same as this chart.

657: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionGetChart()`, `PetscSectionCreate()`, `PetscSectionSetNumFields()`
658: @*/
659: PetscErrorCode PetscSectionSetChart(PetscSection s, PetscInt pStart, PetscInt pEnd)
660: {
661:   PetscInt f;

663:   PetscFunctionBegin;
665:   PetscCheck(pEnd >= pStart, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Chart pEnd %" PetscInt_FMT " cannot be smaller than chart pStart %" PetscInt_FMT, pEnd, pStart);
666:   if (pStart == s->pStart && pEnd == s->pEnd) PetscFunctionReturn(PETSC_SUCCESS);
667:   /* Cannot Reset() because it destroys field information */
668:   s->setup = PETSC_FALSE;
669:   PetscCall(PetscSectionDestroy(&s->bc));
670:   PetscCall(PetscFree(s->bcIndices));
671:   PetscCall(PetscFree2(s->atlasDof, s->atlasOff));

673:   s->pStart = pStart;
674:   s->pEnd   = pEnd;
675:   PetscCall(PetscMalloc2(pEnd - pStart, &s->atlasDof, pEnd - pStart, &s->atlasOff));
676:   PetscCall(PetscArrayzero(s->atlasDof, pEnd - pStart));
677:   for (f = 0; f < s->numFields; ++f) PetscCall(PetscSectionSetChart(s->field[f], pStart, pEnd));
678:   PetscFunctionReturn(PETSC_SUCCESS);
679: }

681: /*@
682:   PetscSectionGetPermutation - Returns the permutation of [0, `pEnd` - `pStart`) or `NULL` that was set with `PetscSectionSetPermutation()`

684:   Not Collective

686:   Input Parameter:
687: . s - the `PetscSection`

689:   Output Parameter:
690: . perm - The permutation as an `IS`

692:   Level: intermediate

694: .seealso: [](sec_scatter), `IS`, `PetscSection`, `PetscSectionSetPermutation()`, `PetscSectionCreate()`
695: @*/
696: PetscErrorCode PetscSectionGetPermutation(PetscSection s, IS *perm)
697: {
698:   PetscFunctionBegin;
700:   if (perm) {
701:     PetscAssertPointer(perm, 2);
702:     *perm = s->perm;
703:   }
704:   PetscFunctionReturn(PETSC_SUCCESS);
705: }

707: /*@
708:   PetscSectionSetPermutation - Sets a permutation of the chart for this section, [0, `pEnd` - `pStart`), which determines the order to store the `PetscSection` information

710:   Not Collective

712:   Input Parameters:
713: + s    - the `PetscSection`
714: - perm - the permutation of points

716:   Level: intermediate

718:   Notes:
719:   The permutation must be provided before `PetscSectionSetUp()`.

721:   The data in the `PetscSection` are permuted but the access via `PetscSectionGetFieldOffset()` and `PetscSectionGetOffset()` is not changed

723:   Compare to `PetscSectionPermute()`

725: .seealso: [](sec_scatter), `IS`, `PetscSection`, `PetscSectionSetUp()`, `PetscSectionGetPermutation()`, `PetscSectionPermute()`, `PetscSectionCreate()`
726: @*/
727: PetscErrorCode PetscSectionSetPermutation(PetscSection s, IS perm)
728: {
729:   PetscFunctionBegin;
732:   PetscCheck(!s->setup, PetscObjectComm((PetscObject)s), PETSC_ERR_ARG_WRONGSTATE, "Cannot set a permutation after the section is setup");
733:   if (s->perm != perm) {
734:     PetscCall(ISDestroy(&s->perm));
735:     if (perm) {
736:       s->perm = perm;
737:       PetscCall(PetscObjectReference((PetscObject)s->perm));
738:     }
739:   }
740:   PetscFunctionReturn(PETSC_SUCCESS);
741: }

743: /*@C
744:   PetscSectionGetBlockStarts - Returns a table indicating which points start new blocks

746:   Not Collective, No Fortran Support

748:   Input Parameter:
749: . s - the `PetscSection`

751:   Output Parameter:
752: . blockStarts - The `PetscBT` with a 1 for each point that begins a block

754:   Notes:
755:   The table is on [0, `pEnd` - `pStart`).

757:   This information is used by `DMCreateMatrix()` to create a variable block size description which is set using `MatSetVariableBlockSizes()`.

759:   Level: intermediate

761: .seealso: [](sec_scatter), `IS`, `PetscSection`, `PetscSectionSetBlockStarts()`, `PetscSectionCreate()`, `DMCreateMatrix()`, `MatSetVariableBlockSizes()`
762: @*/
763: PetscErrorCode PetscSectionGetBlockStarts(PetscSection s, PetscBT *blockStarts)
764: {
765:   PetscFunctionBegin;
767:   if (blockStarts) {
768:     PetscAssertPointer(blockStarts, 2);
769:     *blockStarts = s->blockStarts;
770:   }
771:   PetscFunctionReturn(PETSC_SUCCESS);
772: }

774: /*@C
775:   PetscSectionSetBlockStarts - Sets a table indicating which points start new blocks

777:   Not Collective, No Fortran Support

779:   Input Parameters:
780: + s           - the `PetscSection`
781: - blockStarts - The `PetscBT` with a 1 for each point that begins a block

783:   Level: intermediate

785:   Notes:
786:   The table is on [0, `pEnd` - `pStart`). PETSc takes ownership of the `PetscBT` when it is passed in and will destroy it. The user should not destroy it.

788:   This information is used by `DMCreateMatrix()` to create a variable block size description which is set using `MatSetVariableBlockSizes()`.

790: .seealso: [](sec_scatter), `IS`, `PetscSection`, `PetscSectionGetBlockStarts()`, `PetscSectionCreate()`, `DMCreateMatrix()`, `MatSetVariableBlockSizes()`
791: @*/
792: PetscErrorCode PetscSectionSetBlockStarts(PetscSection s, PetscBT blockStarts)
793: {
794:   PetscFunctionBegin;
796:   if (s->blockStarts != blockStarts) {
797:     PetscCall(PetscBTDestroy(&s->blockStarts));
798:     s->blockStarts = blockStarts;
799:   }
800:   PetscFunctionReturn(PETSC_SUCCESS);
801: }

803: /*@
804:   PetscSectionGetPointMajor - Returns the flag for dof ordering, `PETSC_TRUE` if it is point major, `PETSC_FALSE` if it is field major

806:   Not Collective

808:   Input Parameter:
809: . s - the `PetscSection`

811:   Output Parameter:
812: . pm - the flag for point major ordering

814:   Level: intermediate

816: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionSetPointMajor()`
817: @*/
818: PetscErrorCode PetscSectionGetPointMajor(PetscSection s, PetscBool *pm)
819: {
820:   PetscFunctionBegin;
822:   PetscAssertPointer(pm, 2);
823:   *pm = s->pointMajor;
824:   PetscFunctionReturn(PETSC_SUCCESS);
825: }

827: /*@
828:   PetscSectionSetPointMajor - Sets the flag for dof ordering, `PETSC_TRUE` for point major, otherwise it will be field major

830:   Not Collective

832:   Input Parameters:
833: + s  - the `PetscSection`
834: - pm - the flag for point major ordering

836:   Level: intermediate

838:   Note:
839:   Field-major order is not recommended unless you are managing the entire problem yourself, since many higher-level functions in PETSc depend on point-major order.

841:   Point major order means the degrees of freedom are stored as follows
842: .vb
843:     all the degrees of freedom for each point are stored contiguously, one point after another (respecting a permutation set with `PetscSectionSetPermutation()`)
844:     for each point
845:        the degrees of freedom for each field (starting with the unnamed default field) are listed in order by field
846: .ve

848:   Field major order means the degrees of freedom are stored as follows
849: .vb
850:     all degrees of freedom for each field (including the unnamed default field) are stored contiguously, one field after another
851:     for each field (started with unnamed default field)
852:       the degrees of freedom for each point are listed in order by point (respecting a permutation set with `PetscSectionSetPermutation()`)
853: .ve

855: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionGetPointMajor()`, `PetscSectionSetPermutation()`
856: @*/
857: PetscErrorCode PetscSectionSetPointMajor(PetscSection s, PetscBool pm)
858: {
859:   PetscFunctionBegin;
861:   PetscCheck(!s->setup, PetscObjectComm((PetscObject)s), PETSC_ERR_ARG_WRONGSTATE, "Cannot set the dof ordering after the section is setup");
862:   s->pointMajor = pm;
863:   PetscFunctionReturn(PETSC_SUCCESS);
864: }

866: /*@
867:   PetscSectionGetIncludesConstraints - Returns the flag indicating if constrained dofs were included when computing offsets in the `PetscSection`.
868:   The value is set with `PetscSectionSetIncludesConstraints()`

870:   Not Collective

872:   Input Parameter:
873: . s - the `PetscSection`

875:   Output Parameter:
876: . includesConstraints - the flag indicating if constrained dofs were included when computing offsets

878:   Level: intermediate

880: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionSetIncludesConstraints()`
881: @*/
882: PetscErrorCode PetscSectionGetIncludesConstraints(PetscSection s, PetscBool *includesConstraints)
883: {
884:   PetscFunctionBegin;
886:   PetscAssertPointer(includesConstraints, 2);
887:   *includesConstraints = s->includesConstraints;
888:   PetscFunctionReturn(PETSC_SUCCESS);
889: }

891: /*@
892:   PetscSectionSetIncludesConstraints - Sets the flag indicating if constrained dofs are to be included when computing offsets

894:   Not Collective

896:   Input Parameters:
897: + s                   - the `PetscSection`
898: - includesConstraints - the flag indicating if constrained dofs are to be included when computing offsets

900:   Level: intermediate

902: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionGetIncludesConstraints()`
903: @*/
904: PetscErrorCode PetscSectionSetIncludesConstraints(PetscSection s, PetscBool includesConstraints)
905: {
906:   PetscFunctionBegin;
908:   PetscCheck(!s->setup, PetscObjectComm((PetscObject)s), PETSC_ERR_ARG_WRONGSTATE, "Cannot set includesConstraints after the section is set up");
909:   s->includesConstraints = includesConstraints;
910:   PetscFunctionReturn(PETSC_SUCCESS);
911: }

913: /*@
914:   PetscSectionGetDof - Return the total number of degrees of freedom associated with a given point.

916:   Not Collective

918:   Input Parameters:
919: + s     - the `PetscSection`
920: - point - the point

922:   Output Parameter:
923: . numDof - the number of dof

925:   Level: intermediate

927:   Notes:
928:   In a global section, this size will be negative for points not owned by this process.

930:   This number is for the unnamed default field at the given point plus all degrees of freedom associated with all fields at that point

932: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionSetDof()`, `PetscSectionCreate()`
933: @*/
934: PetscErrorCode PetscSectionGetDof(PetscSection s, PetscInt point, PetscInt *numDof)
935: {
936:   PetscFunctionBeginHot;
938:   PetscAssertPointer(numDof, 3);
939:   PetscAssert(point >= s->pStart && point < s->pEnd, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Section point %" PetscInt_FMT " should be in [%" PetscInt_FMT ", %" PetscInt_FMT ")", point, s->pStart, s->pEnd);
940:   *numDof = s->atlasDof[point - s->pStart];
941:   PetscFunctionReturn(PETSC_SUCCESS);
942: }

944: /*@
945:   PetscSectionSetDof - Sets the total number of degrees of freedom associated with a given point.

947:   Not Collective

949:   Input Parameters:
950: + s      - the `PetscSection`
951: . point  - the point
952: - numDof - the number of dof, these values may be negative -(dof+1) to indicate they are off process

954:   Level: intermediate

956:   Note:
957:   This number is for the unnamed default field at the given point plus all degrees of freedom associated with all fields at that point

959: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionGetDof()`, `PetscSectionAddDof()`, `PetscSectionCreate()`
960: @*/
961: PetscErrorCode PetscSectionSetDof(PetscSection s, PetscInt point, PetscInt numDof)
962: {
963:   PetscFunctionBegin;
965:   PetscAssert(point >= s->pStart && point < s->pEnd, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Section point %" PetscInt_FMT " should be in [%" PetscInt_FMT ", %" PetscInt_FMT ")", point, s->pStart, s->pEnd);
966:   s->atlasDof[point - s->pStart] = numDof;
967:   PetscCall(PetscSectionInvalidateMaxDof_Internal(s));
968:   PetscFunctionReturn(PETSC_SUCCESS);
969: }

971: /*@
972:   PetscSectionAddDof - Adds to the total number of degrees of freedom associated with a given point.

974:   Not Collective

976:   Input Parameters:
977: + s      - the `PetscSection`
978: . point  - the point
979: - numDof - the number of additional dof

981:   Level: intermediate

983:   Note:
984:   This number is for the unnamed default field at the given point plus all degrees of freedom associated with all fields at that point

986: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionGetDof()`, `PetscSectionSetDof()`, `PetscSectionCreate()`
987: @*/
988: PetscErrorCode PetscSectionAddDof(PetscSection s, PetscInt point, PetscInt numDof)
989: {
990:   PetscFunctionBeginHot;
992:   PetscAssert(point >= s->pStart && point < s->pEnd, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Section point %" PetscInt_FMT " should be in [%" PetscInt_FMT ", %" PetscInt_FMT ")", point, s->pStart, s->pEnd);
993:   PetscCheck(numDof >= 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "numDof %" PetscInt_FMT " should not be negative", numDof);
994:   s->atlasDof[point - s->pStart] += numDof;
995:   PetscCall(PetscSectionInvalidateMaxDof_Internal(s));
996:   PetscFunctionReturn(PETSC_SUCCESS);
997: }

999: /*@
1000:   PetscSectionGetFieldDof - Return the number of degrees of freedom associated with a field on a given point.

1002:   Not Collective

1004:   Input Parameters:
1005: + s     - the `PetscSection`
1006: . point - the point
1007: - field - the field

1009:   Output Parameter:
1010: . numDof - the number of dof

1012:   Level: intermediate

1014: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionSetFieldDof()`, `PetscSectionCreate()`
1015: @*/
1016: PetscErrorCode PetscSectionGetFieldDof(PetscSection s, PetscInt point, PetscInt field, PetscInt *numDof)
1017: {
1018:   PetscFunctionBegin;
1020:   PetscAssertPointer(numDof, 4);
1021:   PetscSectionCheckValidField(field, s->numFields);
1022:   PetscCall(PetscSectionGetDof(s->field[field], point, numDof));
1023:   PetscFunctionReturn(PETSC_SUCCESS);
1024: }

1026: /*@
1027:   PetscSectionSetFieldDof - Sets the number of degrees of freedom associated with a field on a given point.

1029:   Not Collective

1031:   Input Parameters:
1032: + s      - the `PetscSection`
1033: . point  - the point
1034: . field  - the field
1035: - numDof - the number of dof, these values may be negative -(dof+1) to indicate they are off process

1037:   Level: intermediate

1039:   Note:
1040:   When setting the number of dof for a field at a point one must also ensure the count of the total number of dof at the point (summed over
1041:   the fields and the unnamed default field) is correct by also calling `PetscSectionAddDof()` or `PetscSectionSetDof()`

1043:   This is equivalent to
1044: .vb
1045:      PetscSection fs;
1046:      PetscSectionGetField(s,field,&fs)
1047:      PetscSectionSetDof(fs,numDof)
1048: .ve

1050: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionGetFieldDof()`, `PetscSectionCreate()`, `PetscSectionAddDof()`, `PetscSectionSetDof()`
1051: @*/
1052: PetscErrorCode PetscSectionSetFieldDof(PetscSection s, PetscInt point, PetscInt field, PetscInt numDof)
1053: {
1054:   PetscFunctionBegin;
1056:   PetscSectionCheckValidField(field, s->numFields);
1057:   PetscCall(PetscSectionSetDof(s->field[field], point, numDof));
1058:   PetscFunctionReturn(PETSC_SUCCESS);
1059: }

1061: /*@
1062:   PetscSectionAddFieldDof - Adds a number of degrees of freedom associated with a field on a given point.

1064:   Not Collective

1066:   Input Parameters:
1067: + s      - the `PetscSection`
1068: . point  - the point
1069: . field  - the field
1070: - numDof - the number of dof

1072:   Level: intermediate

1074:   Notes:
1075:   When adding to the number of dof for a field at a point one must also ensure the count of the total number of dof at the point (summed over
1076:   the fields and the unnamed default field) is correct by also calling `PetscSectionAddDof()` or `PetscSectionSetDof()`

1078:   This is equivalent to
1079: .vb
1080:      PetscSection fs;
1081:      PetscSectionGetField(s,field,&fs)
1082:      PetscSectionAddDof(fs,numDof)
1083: .ve

1085: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionSetFieldDof()`, `PetscSectionGetFieldDof()`, `PetscSectionCreate()`
1086: @*/
1087: PetscErrorCode PetscSectionAddFieldDof(PetscSection s, PetscInt point, PetscInt field, PetscInt numDof)
1088: {
1089:   PetscFunctionBegin;
1091:   PetscSectionCheckValidField(field, s->numFields);
1092:   PetscCall(PetscSectionAddDof(s->field[field], point, numDof));
1093:   PetscFunctionReturn(PETSC_SUCCESS);
1094: }

1096: /*@
1097:   PetscSectionGetConstraintDof - Return the number of constrained degrees of freedom associated with a given point.

1099:   Not Collective

1101:   Input Parameters:
1102: + s     - the `PetscSection`
1103: - point - the point

1105:   Output Parameter:
1106: . numDof - the number of dof which are fixed by constraints

1108:   Level: intermediate

1110: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionGetDof()`, `PetscSectionSetConstraintDof()`, `PetscSectionCreate()`
1111: @*/
1112: PetscErrorCode PetscSectionGetConstraintDof(PetscSection s, PetscInt point, PetscInt *numDof)
1113: {
1114:   PetscFunctionBegin;
1116:   PetscAssertPointer(numDof, 3);
1117:   if (s->bc) {
1118:     PetscCall(PetscSectionGetDof(s->bc, point, numDof));
1119:   } else *numDof = 0;
1120:   PetscFunctionReturn(PETSC_SUCCESS);
1121: }

1123: /*@
1124:   PetscSectionSetConstraintDof - Set the number of constrained degrees of freedom associated with a given point.

1126:   Not Collective

1128:   Input Parameters:
1129: + s      - the `PetscSection`
1130: . point  - the point
1131: - numDof - the number of dof which are fixed by constraints

1133:   Level: intermediate

1135: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionSetDof()`, `PetscSectionGetConstraintDof()`, `PetscSectionCreate()`
1136: @*/
1137: PetscErrorCode PetscSectionSetConstraintDof(PetscSection s, PetscInt point, PetscInt numDof)
1138: {
1139:   PetscFunctionBegin;
1141:   if (numDof) {
1142:     PetscCall(PetscSectionCheckConstraints_Private(s));
1143:     PetscCall(PetscSectionSetDof(s->bc, point, numDof));
1144:   }
1145:   PetscFunctionReturn(PETSC_SUCCESS);
1146: }

1148: /*@
1149:   PetscSectionAddConstraintDof - Increment the number of constrained degrees of freedom associated with a given point.

1151:   Not Collective

1153:   Input Parameters:
1154: + s      - the `PetscSection`
1155: . point  - the point
1156: - numDof - the number of additional dof which are fixed by constraints

1158:   Level: intermediate

1160: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionAddDof()`, `PetscSectionGetConstraintDof()`, `PetscSectionCreate()`
1161: @*/
1162: PetscErrorCode PetscSectionAddConstraintDof(PetscSection s, PetscInt point, PetscInt numDof)
1163: {
1164:   PetscFunctionBegin;
1166:   if (numDof) {
1167:     PetscCall(PetscSectionCheckConstraints_Private(s));
1168:     PetscCall(PetscSectionAddDof(s->bc, point, numDof));
1169:   }
1170:   PetscFunctionReturn(PETSC_SUCCESS);
1171: }

1173: /*@
1174:   PetscSectionGetFieldConstraintDof - Return the number of constrained degrees of freedom associated with a given field on a point.

1176:   Not Collective

1178:   Input Parameters:
1179: + s     - the `PetscSection`
1180: . point - the point
1181: - field - the field

1183:   Output Parameter:
1184: . numDof - the number of dof which are fixed by constraints

1186:   Level: intermediate

1188: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionGetDof()`, `PetscSectionSetFieldConstraintDof()`, `PetscSectionCreate()`
1189: @*/
1190: PetscErrorCode PetscSectionGetFieldConstraintDof(PetscSection s, PetscInt point, PetscInt field, PetscInt *numDof)
1191: {
1192:   PetscFunctionBegin;
1194:   PetscAssertPointer(numDof, 4);
1195:   PetscSectionCheckValidField(field, s->numFields);
1196:   PetscCall(PetscSectionGetConstraintDof(s->field[field], point, numDof));
1197:   PetscFunctionReturn(PETSC_SUCCESS);
1198: }

1200: /*@
1201:   PetscSectionSetFieldConstraintDof - Set the number of constrained degrees of freedom associated with a given field on a point.

1203:   Not Collective

1205:   Input Parameters:
1206: + s      - the `PetscSection`
1207: . point  - the point
1208: . field  - the field
1209: - numDof - the number of dof which are fixed by constraints

1211:   Level: intermediate

1213: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionSetDof()`, `PetscSectionGetFieldConstraintDof()`, `PetscSectionCreate()`
1214: @*/
1215: PetscErrorCode PetscSectionSetFieldConstraintDof(PetscSection s, PetscInt point, PetscInt field, PetscInt numDof)
1216: {
1217:   PetscFunctionBegin;
1219:   PetscSectionCheckValidField(field, s->numFields);
1220:   PetscCall(PetscSectionSetConstraintDof(s->field[field], point, numDof));
1221:   PetscFunctionReturn(PETSC_SUCCESS);
1222: }

1224: /*@
1225:   PetscSectionAddFieldConstraintDof - Increment the number of constrained degrees of freedom associated with a given field on a point.

1227:   Not Collective

1229:   Input Parameters:
1230: + s      - the `PetscSection`
1231: . point  - the point
1232: . field  - the field
1233: - numDof - the number of additional dof which are fixed by constraints

1235:   Level: intermediate

1237: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionAddDof()`, `PetscSectionGetFieldConstraintDof()`, `PetscSectionCreate()`
1238: @*/
1239: PetscErrorCode PetscSectionAddFieldConstraintDof(PetscSection s, PetscInt point, PetscInt field, PetscInt numDof)
1240: {
1241:   PetscFunctionBegin;
1243:   PetscSectionCheckValidField(field, s->numFields);
1244:   PetscCall(PetscSectionAddConstraintDof(s->field[field], point, numDof));
1245:   PetscFunctionReturn(PETSC_SUCCESS);
1246: }

1248: /*@
1249:   PetscSectionSetUpBC - Setup the subsections describing boundary conditions.

1251:   Not Collective

1253:   Input Parameter:
1254: . s - the `PetscSection`

1256:   Level: advanced

1258: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionSetUp()`, `PetscSectionCreate()`
1259: @*/
1260: PetscErrorCode PetscSectionSetUpBC(PetscSection s)
1261: {
1262:   PetscFunctionBegin;
1264:   if (s->bc) {
1265:     const PetscInt last = (s->bc->pEnd - s->bc->pStart) - 1;

1267:     PetscCall(PetscSectionSetUp(s->bc));
1268:     if (last >= 0) PetscCall(PetscMalloc1(s->bc->atlasOff[last] + s->bc->atlasDof[last], &s->bcIndices));
1269:     else s->bcIndices = NULL;
1270:   }
1271:   PetscFunctionReturn(PETSC_SUCCESS);
1272: }

1274: /*@
1275:   PetscSectionSetUp - Calculate offsets based upon the number of degrees of freedom for each point in preparation for use of the `PetscSection`

1277:   Not Collective

1279:   Input Parameter:
1280: . s - the `PetscSection`

1282:   Level: intermediate

1284:   Notes:
1285:   If used, `PetscSectionSetPermutation()` must be called before this routine.

1287:   `PetscSectionSetPointMajor()`, cannot be called after this routine.

1289: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionCreate()`, `PetscSectionSetPermutation()`
1290: @*/
1291: PetscErrorCode PetscSectionSetUp(PetscSection s)
1292: {
1293:   PetscInt        f;
1294:   const PetscInt *pind   = NULL;
1295:   PetscCount      offset = 0;

1297:   PetscFunctionBegin;
1299:   if (s->setup) PetscFunctionReturn(PETSC_SUCCESS);
1300:   s->setup = PETSC_TRUE;
1301:   /* Set offsets and field offsets for all points */
1302:   /*   Assume that all fields have the same chart */
1303:   PetscCheck(s->includesConstraints, PETSC_COMM_SELF, PETSC_ERR_SUP, "PetscSectionSetUp is currently unsupported for includesConstraints = PETSC_TRUE");
1304:   if (s->perm) PetscCall(ISGetIndices(s->perm, &pind));
1305:   if (s->pointMajor) {
1306:     PetscCount foff;
1307:     for (PetscInt p = 0; p < s->pEnd - s->pStart; ++p) {
1308:       const PetscInt q = pind ? pind[p] : p;

1310:       /* Set point offset */
1311:       PetscCall(PetscIntCast(offset, &s->atlasOff[q]));
1312:       offset += s->atlasDof[q];
1313:       /* Set field offset */
1314:       for (f = 0, foff = s->atlasOff[q]; f < s->numFields; ++f) {
1315:         PetscSection sf = s->field[f];

1317:         PetscCall(PetscIntCast(foff, &sf->atlasOff[q]));
1318:         foff += sf->atlasDof[q];
1319:       }
1320:     }
1321:   } else {
1322:     /* Set field offsets for all points */
1323:     for (f = 0; f < s->numFields; ++f) {
1324:       PetscSection sf = s->field[f];

1326:       for (PetscInt p = 0; p < s->pEnd - s->pStart; ++p) {
1327:         const PetscInt q = pind ? pind[p] : p;

1329:         PetscCall(PetscIntCast(offset, &sf->atlasOff[q]));
1330:         offset += sf->atlasDof[q];
1331:       }
1332:     }
1333:     /* Disable point offsets since these are unused */
1334:     for (PetscInt p = 0; p < s->pEnd - s->pStart; ++p) s->atlasOff[p] = -1;
1335:   }
1336:   if (s->perm) PetscCall(ISRestoreIndices(s->perm, &pind));
1337:   /* Setup BC sections */
1338:   PetscCall(PetscSectionSetUpBC(s));
1339:   for (f = 0; f < s->numFields; ++f) PetscCall(PetscSectionSetUpBC(s->field[f]));
1340:   PetscFunctionReturn(PETSC_SUCCESS);
1341: }

1343: /*@
1344:   PetscSectionGetMaxDof - Return the maximum number of degrees of freedom on any point in the `PetscSection`

1346:   Not Collective

1348:   Input Parameter:
1349: . s - the `PetscSection`

1351:   Output Parameter:
1352: . maxDof - the maximum dof

1354:   Level: intermediate

1356:   Notes:
1357:   The returned number is up-to-date without need for `PetscSectionSetUp()`.

1359:   This is the maximum over all points of the sum of the number of dof in the unnamed default field plus all named fields. This is equivalent to
1360:   the maximum over all points of the value returned by `PetscSectionGetDof()` on this MPI process

1362:   Developer Notes:
1363:   The returned number is calculated lazily and stashed.

1365:   A call to `PetscSectionInvalidateMaxDof_Internal()` invalidates the stashed value.

1367:   `PetscSectionInvalidateMaxDof_Internal()` is called in `PetscSectionSetDof()`, `PetscSectionAddDof()` and `PetscSectionReset()`

1369:   It should also be called every time `atlasDof` is modified directly.

1371: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionGetDof()`, `PetscSectionSetDof()`, `PetscSectionAddDof()`, `PetscSectionCreate()`
1372: @*/
1373: PetscErrorCode PetscSectionGetMaxDof(PetscSection s, PetscInt *maxDof)
1374: {
1375:   PetscInt p;

1377:   PetscFunctionBegin;
1379:   PetscAssertPointer(maxDof, 2);
1380:   if (s->maxDof == PETSC_INT_MIN) {
1381:     s->maxDof = 0;
1382:     for (p = 0; p < s->pEnd - s->pStart; ++p) s->maxDof = PetscMax(s->maxDof, s->atlasDof[p]);
1383:   }
1384:   *maxDof = s->maxDof;
1385:   PetscFunctionReturn(PETSC_SUCCESS);
1386: }

1388: /*@
1389:   PetscSectionGetStorageSize - Return the size of an array or local `Vec` capable of holding all the degrees of freedom defined in a `PetscSection`

1391:   Not Collective

1393:   Input Parameter:
1394: . s - the `PetscSection`

1396:   Output Parameter:
1397: . size - the size of an array which can hold all the dofs

1399:   Level: intermediate

1401: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionGetOffset()`, `PetscSectionGetConstrainedStorageSize()`, `PetscSectionCreate()`
1402: @*/
1403: PetscErrorCode PetscSectionGetStorageSize(PetscSection s, PetscInt *size)
1404: {
1405:   PetscInt64 n = 0;

1407:   PetscFunctionBegin;
1409:   PetscAssertPointer(size, 2);
1410:   for (PetscInt p = 0; p < s->pEnd - s->pStart; ++p) n += s->atlasDof[p] > 0 ? s->atlasDof[p] : 0;
1411:   PetscCall(PetscIntCast(n, size));
1412:   PetscFunctionReturn(PETSC_SUCCESS);
1413: }

1415: /*@
1416:   PetscSectionGetConstrainedStorageSize - Return the size of an array or local `Vec` capable of holding all unconstrained degrees of freedom in a `PetscSection`

1418:   Not Collective

1420:   Input Parameter:
1421: . s - the `PetscSection`

1423:   Output Parameter:
1424: . size - the size of an array which can hold all unconstrained dofs

1426:   Level: intermediate

1428: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionGetStorageSize()`, `PetscSectionGetOffset()`, `PetscSectionCreate()`
1429: @*/
1430: PetscErrorCode PetscSectionGetConstrainedStorageSize(PetscSection s, PetscInt *size)
1431: {
1432:   PetscInt64 n = 0;

1434:   PetscFunctionBegin;
1436:   PetscAssertPointer(size, 2);
1437:   for (PetscInt p = 0; p < s->pEnd - s->pStart; ++p) {
1438:     const PetscInt cdof = s->bc ? s->bc->atlasDof[p] : 0;
1439:     n += s->atlasDof[p] > 0 ? s->atlasDof[p] - cdof : 0;
1440:   }
1441:   PetscCall(PetscIntCast(n, size));
1442:   PetscFunctionReturn(PETSC_SUCCESS);
1443: }

1445: /*@
1446:   PetscSectionCreateGlobalSection - Create a parallel section describing the global layout using
1447:   a local (sequential) `PetscSection` on each MPI process and a `PetscSF` describing the section point overlap.

1449:   Input Parameters:
1450: + s                  - The `PetscSection` for the local field layout
1451: . sf                 - The `PetscSF` describing parallel layout of the section points (leaves are unowned local points)
1452: . usePermutation     - By default this is `PETSC_TRUE`, meaning any permutation of the local section is transferred to the global section
1453: . includeConstraints - By default this is `PETSC_FALSE`, meaning that the global field vector will not possess constrained dofs
1454: - localOffsets       - If `PETSC_TRUE`, use local rather than global offsets for the points

1456:   Output Parameter:
1457: . gsection - The `PetscSection` for the global field layout

1459:   Level: intermediate

1461:   Notes:
1462:   On each MPI process `gsection` inherits the chart of the `s` on that process.

1464:   This sets negative sizes and offsets to points not owned by this process as defined by `sf` but that are within the local value of the chart of `gsection`.
1465:   In those locations the value of size is -(size+1) and the value of the offset on the remote process is -(off+1).

1467: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionCreate()`, `PetscSectionCreateGlobalSectionCensored()`
1468: @*/
1469: PetscErrorCode PetscSectionCreateGlobalSection(PetscSection s, PetscSF sf, PetscBool usePermutation, PetscBool includeConstraints, PetscBool localOffsets, PetscSection *gsection)
1470: {
1471:   PetscSection    gs;
1472:   const PetscInt *pind = NULL;
1473:   PetscInt       *recv = NULL, *neg = NULL;
1474:   PetscInt        pStart, pEnd, p, dof, cdof, off, globalOff = 0, nroots, nlocal, maxleaf;
1475:   PetscInt        numFields, f, numComponents;
1476:   PetscCount      foff;

1478:   PetscFunctionBegin;
1484:   PetscAssertPointer(gsection, 6);
1485:   PetscCheck(s->pointMajor, PETSC_COMM_SELF, PETSC_ERR_SUP, "No support for field major ordering");
1486:   PetscCall(PetscSectionCreate(PetscObjectComm((PetscObject)s), &gs));
1487:   PetscCall(PetscSectionGetNumFields(s, &numFields));
1488:   if (numFields > 0) PetscCall(PetscSectionSetNumFields(gs, numFields));
1489:   PetscCall(PetscSectionGetChart(s, &pStart, &pEnd));
1490:   PetscCall(PetscSectionSetChart(gs, pStart, pEnd));
1491:   gs->includesConstraints = includeConstraints;
1492:   PetscCall(PetscSFGetGraph(sf, &nroots, NULL, NULL, NULL));
1493:   nlocal = nroots; /* The local/leaf space matches global/root space */
1494:   /* Must allocate for all points visible to SF, which may be more than this section */
1495:   if (nroots >= 0) { /* nroots < 0 means that the graph has not been set, only happens in serial */
1496:     PetscCall(PetscSFGetLeafRange(sf, NULL, &maxleaf));
1497:     PetscCheck(nroots >= pEnd, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "SF roots %" PetscInt_FMT " < pEnd %" PetscInt_FMT, nroots, pEnd);
1498:     PetscCheck(maxleaf < nroots, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Max local leaf %" PetscInt_FMT " >= nroots %" PetscInt_FMT, maxleaf, nroots);
1499:     PetscCall(PetscMalloc2(nroots, &neg, nlocal, &recv));
1500:     PetscCall(PetscArrayzero(neg, nroots));
1501:   }
1502:   /* Mark all local points with negative dof */
1503:   for (p = pStart; p < pEnd; ++p) {
1504:     PetscCall(PetscSectionGetDof(s, p, &dof));
1505:     PetscCall(PetscSectionSetDof(gs, p, dof));
1506:     PetscCall(PetscSectionGetConstraintDof(s, p, &cdof));
1507:     if (!includeConstraints && cdof > 0) PetscCall(PetscSectionSetConstraintDof(gs, p, cdof));
1508:     if (neg) neg[p] = -(dof + 1);
1509:   }
1510:   PetscCall(PetscSectionSetUpBC(gs));
1511:   if (gs->bcIndices) PetscCall(PetscArraycpy(gs->bcIndices, s->bcIndices, gs->bc->atlasOff[gs->bc->pEnd - gs->bc->pStart - 1] + gs->bc->atlasDof[gs->bc->pEnd - gs->bc->pStart - 1]));
1512:   if (nroots >= 0) {
1513:     PetscCall(PetscArrayzero(recv, nlocal));
1514:     PetscCall(PetscSFBcastBegin(sf, MPIU_INT, neg, recv, MPI_REPLACE));
1515:     PetscCall(PetscSFBcastEnd(sf, MPIU_INT, neg, recv, MPI_REPLACE));
1516:     for (p = pStart; p < pEnd; ++p) {
1517:       if (recv[p] < 0) {
1518:         gs->atlasDof[p - pStart] = recv[p];
1519:         PetscCall(PetscSectionGetDof(s, p, &dof));
1520:         PetscCheck(-(recv[p] + 1) == dof, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Global dof %" PetscInt_FMT " for point %" PetscInt_FMT " is not the unconstrained %" PetscInt_FMT, -(recv[p] + 1), p, dof);
1521:       }
1522:     }
1523:   }
1524:   /* Calculate new sizes, get process offset, and calculate point offsets */
1525:   if (usePermutation && s->perm) PetscCall(ISGetIndices(s->perm, &pind));
1526:   for (p = 0, off = 0; p < pEnd - pStart; ++p) {
1527:     const PetscInt q = pind ? pind[p] : p;

1529:     cdof            = (!includeConstraints && s->bc) ? s->bc->atlasDof[q] : 0;
1530:     gs->atlasOff[q] = off;
1531:     off += gs->atlasDof[q] > 0 ? gs->atlasDof[q] - cdof : 0;
1532:   }
1533:   if (!localOffsets) {
1534:     PetscCallMPI(MPI_Scan(&off, &globalOff, 1, MPIU_INT, MPI_SUM, PetscObjectComm((PetscObject)s)));
1535:     globalOff -= off;
1536:   }
1537:   for (p = pStart, off = 0; p < pEnd; ++p) {
1538:     gs->atlasOff[p - pStart] += globalOff;
1539:     if (neg) neg[p] = -(gs->atlasOff[p - pStart] + 1);
1540:   }
1541:   if (usePermutation && s->perm) PetscCall(ISRestoreIndices(s->perm, &pind));
1542:   /* Put in negative offsets for ghost points */
1543:   if (nroots >= 0) {
1544:     PetscCall(PetscArrayzero(recv, nlocal));
1545:     PetscCall(PetscSFBcastBegin(sf, MPIU_INT, neg, recv, MPI_REPLACE));
1546:     PetscCall(PetscSFBcastEnd(sf, MPIU_INT, neg, recv, MPI_REPLACE));
1547:     for (p = pStart; p < pEnd; ++p) {
1548:       if (recv[p] < 0) gs->atlasOff[p - pStart] = recv[p];
1549:     }
1550:   }
1551:   PetscCall(PetscFree2(neg, recv));
1552:   /* Set field dofs/offsets/constraints */
1553:   for (f = 0; f < numFields; ++f) {
1554:     const char *name;

1556:     gs->field[f]->includesConstraints = includeConstraints;
1557:     PetscCall(PetscSectionGetFieldComponents(s, f, &numComponents));
1558:     PetscCall(PetscSectionSetFieldComponents(gs, f, numComponents));
1559:     PetscCall(PetscSectionGetFieldName(s, f, &name));
1560:     PetscCall(PetscSectionSetFieldName(gs, f, name));
1561:   }
1562:   for (p = pStart; p < pEnd; ++p) {
1563:     PetscCall(PetscSectionGetOffset(gs, p, &off));
1564:     for (f = 0, foff = off; f < numFields; ++f) {
1565:       PetscCall(PetscSectionGetFieldConstraintDof(s, p, f, &cdof));
1566:       if (!includeConstraints && cdof > 0) PetscCall(PetscSectionSetFieldConstraintDof(gs, p, f, cdof));
1567:       PetscCall(PetscSectionGetFieldDof(s, p, f, &dof));
1568:       PetscCall(PetscSectionSetFieldDof(gs, p, f, off < 0 ? -(dof + 1) : dof));
1569:       PetscCall(PetscSectionSetFieldOffset(gs, p, f, (PetscInt)foff));
1570:       PetscCall(PetscSectionGetFieldConstraintDof(gs, p, f, &cdof));
1571:       foff = off < 0 ? foff - (dof - cdof) : foff + (dof - cdof);
1572:       PetscCheck(foff < PETSC_INT_MAX, PETSC_COMM_SELF, PETSC_ERR_INT_OVERFLOW, "Offsets too large for 32 bit indices");
1573:     }
1574:   }
1575:   for (f = 0; f < numFields; ++f) {
1576:     PetscSection gfs = gs->field[f];

1578:     PetscCall(PetscSectionSetUpBC(gfs));
1579:     if (gfs->bcIndices) PetscCall(PetscArraycpy(gfs->bcIndices, s->field[f]->bcIndices, gfs->bc->atlasOff[gfs->bc->pEnd - gfs->bc->pStart - 1] + gfs->bc->atlasDof[gfs->bc->pEnd - gfs->bc->pStart - 1]));
1580:   }
1581:   gs->setup = PETSC_TRUE;
1582:   PetscCall(PetscSectionViewFromOptions(gs, NULL, "-global_section_view"));
1583:   *gsection = gs;
1584:   PetscFunctionReturn(PETSC_SUCCESS);
1585: }

1587: /*@
1588:   PetscSectionCreateGlobalSectionCensored - Create a `PetscSection` describing the globallayout using
1589:   a local (sequential) `PetscSection` on each MPI process and an `PetscSF` describing the section point overlap.

1591:   Input Parameters:
1592: + s                  - The `PetscSection` for the local field layout
1593: . sf                 - The `PetscSF` describing parallel layout of the section points
1594: . includeConstraints - By default this is `PETSC_FALSE`, meaning that the global vector will not possess constrained dofs
1595: . numExcludes        - The number of exclusion ranges, this must have the same value on all MPI processes
1596: - excludes           - An array [start_0, end_0, start_1, end_1, ...] where there are `numExcludes` pairs and must have the same values on all MPI processes

1598:   Output Parameter:
1599: . gsection - The `PetscSection` for the global field layout

1601:   Level: advanced

1603:   Notes:
1604:   On each MPI process `gsection` inherits the chart of the `s` on that process.

1606:   This sets negative sizes and offsets to points not owned by this process as defined by `sf` but that are within the local value of the chart of `gsection`.
1607:   In those locations the value of size is -(size+1) and the value of the offset on the remote process is -(off+1).

1609:   This routine augments `PetscSectionCreateGlobalSection()` by allowing one to exclude certain ranges in the chart of the `PetscSection`

1611:   Developer Notes:
1612:   This is a terrible function name

1614: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionCreate()`
1615: @*/
1616: PetscErrorCode PetscSectionCreateGlobalSectionCensored(PetscSection s, PetscSF sf, PetscBool includeConstraints, PetscInt numExcludes, const PetscInt excludes[], PetscSection *gsection)
1617: {
1618:   const PetscInt *pind = NULL;
1619:   PetscInt       *neg = NULL, *tmpOff = NULL;
1620:   PetscInt        pStart, pEnd, p, e, dof, cdof, globalOff = 0, nroots;
1621:   PetscCount      off;

1623:   PetscFunctionBegin;
1626:   PetscAssertPointer(gsection, 6);
1627:   PetscCall(PetscSectionCreate(PetscObjectComm((PetscObject)s), gsection));
1628:   PetscCall(PetscSectionGetChart(s, &pStart, &pEnd));
1629:   PetscCall(PetscSectionSetChart(*gsection, pStart, pEnd));
1630:   PetscCall(PetscSFGetGraph(sf, &nroots, NULL, NULL, NULL));
1631:   if (nroots >= 0) {
1632:     PetscCheck(nroots >= pEnd - pStart, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "PetscSF nroots %" PetscInt_FMT " < %" PetscInt_FMT " section size", nroots, pEnd - pStart);
1633:     PetscCall(PetscCalloc1(nroots, &neg));
1634:     if (nroots > pEnd - pStart) {
1635:       PetscCall(PetscCalloc1(nroots, &tmpOff));
1636:     } else {
1637:       tmpOff = &(*gsection)->atlasDof[-pStart];
1638:     }
1639:   }
1640:   /* Mark ghost points with negative dof */
1641:   for (p = pStart; p < pEnd; ++p) {
1642:     for (e = 0; e < numExcludes; ++e) {
1643:       if ((p >= excludes[e * 2 + 0]) && (p < excludes[e * 2 + 1])) {
1644:         PetscCall(PetscSectionSetDof(*gsection, p, 0));
1645:         break;
1646:       }
1647:     }
1648:     if (e < numExcludes) continue;
1649:     PetscCall(PetscSectionGetDof(s, p, &dof));
1650:     PetscCall(PetscSectionSetDof(*gsection, p, dof));
1651:     PetscCall(PetscSectionGetConstraintDof(s, p, &cdof));
1652:     if (!includeConstraints && cdof > 0) PetscCall(PetscSectionSetConstraintDof(*gsection, p, cdof));
1653:     if (neg) neg[p] = -(dof + 1);
1654:   }
1655:   PetscCall(PetscSectionSetUpBC(*gsection));
1656:   if (nroots >= 0) {
1657:     PetscCall(PetscSFBcastBegin(sf, MPIU_INT, neg, tmpOff, MPI_REPLACE));
1658:     PetscCall(PetscSFBcastEnd(sf, MPIU_INT, neg, tmpOff, MPI_REPLACE));
1659:     if (nroots > pEnd - pStart) {
1660:       for (p = pStart; p < pEnd; ++p) {
1661:         if (tmpOff[p] < 0) (*gsection)->atlasDof[p - pStart] = tmpOff[p];
1662:       }
1663:     }
1664:   }
1665:   /* Calculate new sizes, get process offset, and calculate point offsets */
1666:   if (s->perm) PetscCall(ISGetIndices(s->perm, &pind));
1667:   for (p = 0, off = 0; p < pEnd - pStart; ++p) {
1668:     const PetscInt q = pind ? pind[p] : p;

1670:     cdof                     = (!includeConstraints && s->bc) ? s->bc->atlasDof[q] : 0;
1671:     (*gsection)->atlasOff[q] = (PetscInt)off;
1672:     off += (*gsection)->atlasDof[q] > 0 ? (*gsection)->atlasDof[q] - cdof : 0;
1673:     PetscCheck(off < PETSC_INT_MAX, PETSC_COMM_SELF, PETSC_ERR_INT_OVERFLOW, "Offsets too large for 32 bit indices");
1674:   }
1675:   PetscCallMPI(MPI_Scan(&off, &globalOff, 1, MPIU_INT, MPI_SUM, PetscObjectComm((PetscObject)s)));
1676:   globalOff -= off;
1677:   for (p = 0, off = 0; p < pEnd - pStart; ++p) {
1678:     (*gsection)->atlasOff[p] += globalOff;
1679:     if (neg) neg[p + pStart] = -((*gsection)->atlasOff[p] + 1);
1680:   }
1681:   if (s->perm) PetscCall(ISRestoreIndices(s->perm, &pind));
1682:   /* Put in negative offsets for ghost points */
1683:   if (nroots >= 0) {
1684:     if (nroots == pEnd - pStart) tmpOff = &(*gsection)->atlasOff[-pStart];
1685:     PetscCall(PetscSFBcastBegin(sf, MPIU_INT, neg, tmpOff, MPI_REPLACE));
1686:     PetscCall(PetscSFBcastEnd(sf, MPIU_INT, neg, tmpOff, MPI_REPLACE));
1687:     if (nroots > pEnd - pStart) {
1688:       for (p = pStart; p < pEnd; ++p) {
1689:         if (tmpOff[p] < 0) (*gsection)->atlasOff[p - pStart] = tmpOff[p];
1690:       }
1691:     }
1692:   }
1693:   if (nroots >= 0 && nroots > pEnd - pStart) PetscCall(PetscFree(tmpOff));
1694:   PetscCall(PetscFree(neg));
1695:   PetscFunctionReturn(PETSC_SUCCESS);
1696: }

1698: /*@
1699:   PetscSectionGetPointLayout - Get a `PetscLayout` for the points with nonzero dof counts of the unnamed default field within this `PetscSection`s local chart

1701:   Collective

1703:   Input Parameters:
1704: + comm - The `MPI_Comm`
1705: - s    - The `PetscSection`

1707:   Output Parameter:
1708: . layout - The point layout for the data that defines the section

1710:   Level: advanced

1712:   Notes:
1713:   `PetscSectionGetValueLayout()` provides similar information but counting the total number of degrees of freedom on the MPI process (excluding constrained
1714:   degrees of freedom).

1716:   This count includes constrained degrees of freedom

1718:   This is usually called on the default global section.

1720:   Example:
1721: .vb
1722:      The chart is [2,5), point 2 has 2 dof, point 3 has 0 dof, point 4 has 1 dof
1723:      The local size of the `PetscLayout` is 2 since 2 points have a non-zero number of dof
1724: .ve

1726:   Developer Notes:
1727:   I find the names of these two functions extremely non-informative

1729: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionGetValueLayout()`, `PetscSectionCreate()`
1730: @*/
1731: PetscErrorCode PetscSectionGetPointLayout(MPI_Comm comm, PetscSection s, PetscLayout *layout)
1732: {
1733:   PetscInt pStart, pEnd, p, localSize = 0;

1735:   PetscFunctionBegin;
1736:   PetscCall(PetscSectionGetChart(s, &pStart, &pEnd));
1737:   for (p = pStart; p < pEnd; ++p) {
1738:     PetscInt dof;

1740:     PetscCall(PetscSectionGetDof(s, p, &dof));
1741:     if (dof >= 0) ++localSize;
1742:   }
1743:   PetscCall(PetscLayoutCreate(comm, layout));
1744:   PetscCall(PetscLayoutSetLocalSize(*layout, localSize));
1745:   PetscCall(PetscLayoutSetBlockSize(*layout, 1));
1746:   PetscCall(PetscLayoutSetUp(*layout));
1747:   PetscFunctionReturn(PETSC_SUCCESS);
1748: }

1750: /*@
1751:   PetscSectionGetValueLayout - Get the `PetscLayout` associated with the section dofs of a `PetscSection`

1753:   Collective

1755:   Input Parameters:
1756: + comm - The `MPI_Comm`
1757: - s    - The `PetscSection`

1759:   Output Parameter:
1760: . layout - The dof layout for the section

1762:   Level: advanced

1764:   Notes:
1765:   `PetscSectionGetPointLayout()` provides similar information but only counting the number of points with nonzero degrees of freedom and
1766:   including the constrained degrees of freedom

1768:   This is usually called for the default global section.

1770:   Example:
1771: .vb
1772:      The chart is [2,5), point 2 has 4 dof (2 constrained), point 3 has 0 dof, point 4 has 1 dof (not constrained)
1773:      The local size of the `PetscLayout` is 3 since there are 3 unconstrained degrees of freedom on this MPI process
1774: .ve

1776: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionGetPointLayout()`, `PetscSectionCreate()`
1777: @*/
1778: PetscErrorCode PetscSectionGetValueLayout(MPI_Comm comm, PetscSection s, PetscLayout *layout)
1779: {
1780:   PetscInt pStart, pEnd, p, localSize = 0;

1782:   PetscFunctionBegin;
1784:   PetscAssertPointer(layout, 3);
1785:   PetscCall(PetscSectionGetChart(s, &pStart, &pEnd));
1786:   for (p = pStart; p < pEnd; ++p) {
1787:     PetscInt dof, cdof;

1789:     PetscCall(PetscSectionGetDof(s, p, &dof));
1790:     PetscCall(PetscSectionGetConstraintDof(s, p, &cdof));
1791:     if (dof - cdof > 0) localSize += dof - cdof;
1792:   }
1793:   PetscCall(PetscLayoutCreate(comm, layout));
1794:   PetscCall(PetscLayoutSetLocalSize(*layout, localSize));
1795:   PetscCall(PetscLayoutSetBlockSize(*layout, 1));
1796:   PetscCall(PetscLayoutSetUp(*layout));
1797:   PetscFunctionReturn(PETSC_SUCCESS);
1798: }

1800: /*@
1801:   PetscSectionGetOffset - Return the offset into an array or `Vec` for the dof associated with the given point.

1803:   Not Collective

1805:   Input Parameters:
1806: + s     - the `PetscSection`
1807: - point - the point

1809:   Output Parameter:
1810: . offset - the offset

1812:   Level: intermediate

1814:   Notes:
1815:   In a global section, `offset` will be negative for points not owned by this process.

1817:   This is for the unnamed default field in the `PetscSection` not the named fields

1819:   The `offset` values are different depending on a value set with `PetscSectionSetPointMajor()`

1821: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionGetFieldOffset()`, `PetscSectionCreate()`, `PetscSectionSetPointMajor()`
1822: @*/
1823: PetscErrorCode PetscSectionGetOffset(PetscSection s, PetscInt point, PetscInt *offset)
1824: {
1825:   PetscFunctionBegin;
1827:   PetscAssertPointer(offset, 3);
1828:   PetscAssert(!(point < s->pStart) && !(point >= s->pEnd), PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Section point %" PetscInt_FMT " should be in [%" PetscInt_FMT ", %" PetscInt_FMT ")", point, s->pStart, s->pEnd);
1829:   *offset = s->atlasOff[point - s->pStart];
1830:   PetscFunctionReturn(PETSC_SUCCESS);
1831: }

1833: /*@
1834:   PetscSectionSetOffset - Set the offset into an array or `Vec` for the dof associated with the given point.

1836:   Not Collective

1838:   Input Parameters:
1839: + s      - the `PetscSection`
1840: . point  - the point
1841: - offset - the offset, these values may be negative indicating the values are off process

1843:   Level: developer

1845:   Note:
1846:   The user usually does not call this function, but uses `PetscSectionSetUp()`

1848: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionGetFieldOffset()`, `PetscSectionCreate()`, `PetscSectionSetUp()`
1849: @*/
1850: PetscErrorCode PetscSectionSetOffset(PetscSection s, PetscInt point, PetscInt offset)
1851: {
1852:   PetscFunctionBegin;
1854:   PetscCheck(!(point < s->pStart) && !(point >= s->pEnd), PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Section point %" PetscInt_FMT " should be in [%" PetscInt_FMT ", %" PetscInt_FMT ")", point, s->pStart, s->pEnd);
1855:   s->atlasOff[point - s->pStart] = offset;
1856:   PetscFunctionReturn(PETSC_SUCCESS);
1857: }

1859: /*@
1860:   PetscSectionGetFieldOffset - Return the offset into an array or `Vec` for the field dof associated with the given point.

1862:   Not Collective

1864:   Input Parameters:
1865: + s     - the `PetscSection`
1866: . point - the point
1867: - field - the field

1869:   Output Parameter:
1870: . offset - the offset

1872:   Level: intermediate

1874:   Notes:
1875:   In a global section, `offset` will be negative for points not owned by this process.

1877:   The `offset` values are different depending on a value set with `PetscSectionSetPointMajor()`

1879: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionGetOffset()`, `PetscSectionCreate()`, `PetscSectionGetFieldPointOffset()`
1880: @*/
1881: PetscErrorCode PetscSectionGetFieldOffset(PetscSection s, PetscInt point, PetscInt field, PetscInt *offset)
1882: {
1883:   PetscFunctionBegin;
1885:   PetscAssertPointer(offset, 4);
1886:   PetscSectionCheckValidField(field, s->numFields);
1887:   PetscCall(PetscSectionGetOffset(s->field[field], point, offset));
1888:   PetscFunctionReturn(PETSC_SUCCESS);
1889: }

1891: /*@
1892:   PetscSectionSetFieldOffset - Set the offset into an array or `Vec` for the dof associated with the given field at a point.

1894:   Not Collective

1896:   Input Parameters:
1897: + s      - the `PetscSection`
1898: . point  - the point
1899: . field  - the field
1900: - offset - the offset, these values may be negative indicating the values are off process

1902:   Level: developer

1904:   Note:
1905:   The user usually does not call this function, but uses `PetscSectionSetUp()`

1907: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionGetFieldOffset()`, `PetscSectionSetOffset()`, `PetscSectionCreate()`, `PetscSectionSetUp()`
1908: @*/
1909: PetscErrorCode PetscSectionSetFieldOffset(PetscSection s, PetscInt point, PetscInt field, PetscInt offset)
1910: {
1911:   PetscFunctionBegin;
1913:   PetscSectionCheckValidField(field, s->numFields);
1914:   PetscCall(PetscSectionSetOffset(s->field[field], point, offset));
1915:   PetscFunctionReturn(PETSC_SUCCESS);
1916: }

1918: /*@
1919:   PetscSectionGetFieldPointOffset - Return the offset for the first field dof associated with the given point relative to the offset for that point for the
1920:   unnamed default field's first dof

1922:   Not Collective

1924:   Input Parameters:
1925: + s     - the `PetscSection`
1926: . point - the point
1927: - field - the field

1929:   Output Parameter:
1930: . offset - the offset

1932:   Level: advanced

1934:   Note:
1935:   This ignores constraints

1937:   Example:
1938: .vb
1939:   if PetscSectionSetPointMajor(s,PETSC_TRUE)
1940:   The unnamed default field has 3 dof at `point`
1941:   Field 0 has 2 dof at `point`
1942:   Then PetscSectionGetFieldPointOffset(s,point,1,&offset) returns and offset of 5
1943: .ve

1945: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionGetOffset()`, `PetscSectionCreate()`, `PetscSectionGetFieldOffset()`
1946: @*/
1947: PetscErrorCode PetscSectionGetFieldPointOffset(PetscSection s, PetscInt point, PetscInt field, PetscInt *offset)
1948: {
1949:   PetscInt off, foff;

1951:   PetscFunctionBegin;
1953:   PetscAssertPointer(offset, 4);
1954:   PetscSectionCheckValidField(field, s->numFields);
1955:   PetscCall(PetscSectionGetOffset(s, point, &off));
1956:   PetscCall(PetscSectionGetOffset(s->field[field], point, &foff));
1957:   *offset = foff - off;
1958:   PetscFunctionReturn(PETSC_SUCCESS);
1959: }

1961: /*@
1962:   PetscSectionGetOffsetRange - Return the full range of offsets [`start`, `end`) for a `PetscSection`

1964:   Not Collective

1966:   Input Parameter:
1967: . s - the `PetscSection`

1969:   Output Parameters:
1970: + start - the minimum offset
1971: - end   - one more than the maximum offset

1973:   Level: intermediate

1975: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionGetOffset()`, `PetscSectionCreate()`
1976: @*/
1977: PetscErrorCode PetscSectionGetOffsetRange(PetscSection s, PetscInt *start, PetscInt *end)
1978: {
1979:   PetscInt os = 0, oe = 0, pStart, pEnd, p;

1981:   PetscFunctionBegin;
1983:   if (s->atlasOff) {
1984:     os = s->atlasOff[0];
1985:     oe = s->atlasOff[0];
1986:   }
1987:   PetscCall(PetscSectionGetChart(s, &pStart, &pEnd));
1988:   for (p = 0; p < pEnd - pStart; ++p) {
1989:     PetscInt dof = s->atlasDof[p], off = s->atlasOff[p];

1991:     if (off >= 0) {
1992:       os = PetscMin(os, off);
1993:       oe = PetscMax(oe, off + dof);
1994:     }
1995:   }
1996:   if (start) *start = os;
1997:   if (end) *end = oe;
1998:   PetscFunctionReturn(PETSC_SUCCESS);
1999: }

2001: /*@
2002:   PetscSectionCreateSubsection - Create a new, smaller `PetscSection` composed of only selected fields

2004:   Collective

2006:   Input Parameters:
2007: + s      - the `PetscSection`
2008: . len    - the number of subfields
2009: - fields - the subfield numbers

2011:   Output Parameter:
2012: . subs - the subsection

2014:   Level: advanced

2016:   Notes:
2017:   The chart of `subs` is the same as the chart of `s`

2019:   This will error if a fieldnumber is out of range

2021: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionCreateSupersection()`, `PetscSectionCreate()`
2022: @*/
2023: PetscErrorCode PetscSectionCreateSubsection(PetscSection s, PetscInt len, const PetscInt fields[], PetscSection *subs)
2024: {
2025:   PetscInt nF, f, c, pStart, pEnd, p, maxCdof = 0;

2027:   PetscFunctionBegin;
2028:   if (!len) PetscFunctionReturn(PETSC_SUCCESS);
2030:   PetscAssertPointer(fields, 3);
2031:   PetscAssertPointer(subs, 4);
2032:   PetscCall(PetscSectionGetNumFields(s, &nF));
2033:   PetscCheck(len <= nF, PetscObjectComm((PetscObject)s), PETSC_ERR_ARG_WRONG, "Number of requested fields %" PetscInt_FMT " greater than number of fields %" PetscInt_FMT, len, nF);
2034:   PetscCall(PetscSectionCreate(PetscObjectComm((PetscObject)s), subs));
2035:   PetscCall(PetscSectionSetNumFields(*subs, len));
2036:   for (f = 0; f < len; ++f) {
2037:     const char     *name    = NULL;
2038:     PetscInt        numComp = 0;
2039:     PetscSectionSym sym;

2041:     PetscCall(PetscSectionGetFieldName(s, fields[f], &name));
2042:     PetscCall(PetscSectionSetFieldName(*subs, f, name));
2043:     PetscCall(PetscSectionGetFieldComponents(s, fields[f], &numComp));
2044:     PetscCall(PetscSectionSetFieldComponents(*subs, f, numComp));
2045:     for (c = 0; c < s->numFieldComponents[fields[f]]; ++c) {
2046:       PetscCall(PetscSectionGetComponentName(s, fields[f], c, &name));
2047:       PetscCall(PetscSectionSetComponentName(*subs, f, c, name));
2048:     }
2049:     PetscCall(PetscSectionGetFieldSym(s, fields[f], &sym));
2050:     PetscCall(PetscSectionSetFieldSym(*subs, f, sym));
2051:   }
2052:   PetscCall(PetscSectionGetChart(s, &pStart, &pEnd));
2053:   PetscCall(PetscSectionSetChart(*subs, pStart, pEnd));
2054:   for (p = pStart; p < pEnd; ++p) {
2055:     PetscInt dof = 0, cdof = 0, fdof = 0, cfdof = 0;

2057:     for (f = 0; f < len; ++f) {
2058:       PetscCall(PetscSectionGetFieldDof(s, p, fields[f], &fdof));
2059:       PetscCall(PetscSectionSetFieldDof(*subs, p, f, fdof));
2060:       PetscCall(PetscSectionGetFieldConstraintDof(s, p, fields[f], &cfdof));
2061:       if (cfdof) PetscCall(PetscSectionSetFieldConstraintDof(*subs, p, f, cfdof));
2062:       dof += fdof;
2063:       cdof += cfdof;
2064:     }
2065:     PetscCall(PetscSectionSetDof(*subs, p, dof));
2066:     if (cdof) PetscCall(PetscSectionSetConstraintDof(*subs, p, cdof));
2067:     maxCdof = PetscMax(cdof, maxCdof);
2068:   }
2069:   PetscCall(PetscSectionSetUp(*subs));
2070:   if (maxCdof) {
2071:     PetscInt *indices;

2073:     PetscCall(PetscMalloc1(maxCdof, &indices));
2074:     for (p = pStart; p < pEnd; ++p) {
2075:       PetscInt cdof;

2077:       PetscCall(PetscSectionGetConstraintDof(*subs, p, &cdof));
2078:       if (cdof) {
2079:         const PetscInt *oldIndices = NULL;
2080:         PetscInt        fdof = 0, cfdof = 0, fc, numConst = 0, fOff = 0;

2082:         for (f = 0; f < len; ++f) {
2083:           PetscCall(PetscSectionGetFieldDof(s, p, fields[f], &fdof));
2084:           PetscCall(PetscSectionGetFieldConstraintDof(s, p, fields[f], &cfdof));
2085:           PetscCall(PetscSectionGetFieldConstraintIndices(s, p, fields[f], &oldIndices));
2086:           PetscCall(PetscSectionSetFieldConstraintIndices(*subs, p, f, oldIndices));
2087:           for (fc = 0; fc < cfdof; ++fc) indices[numConst + fc] = oldIndices[fc] + fOff;
2088:           numConst += cfdof;
2089:           fOff += fdof;
2090:         }
2091:         PetscCall(PetscSectionSetConstraintIndices(*subs, p, indices));
2092:       }
2093:     }
2094:     PetscCall(PetscFree(indices));
2095:   }
2096:   PetscFunctionReturn(PETSC_SUCCESS);
2097: }

2099: /*@
2100:   PetscSectionCreateComponentSubsection - Create a new, smaller `PetscSection` composed of only selected components

2102:   Collective

2104:   Input Parameters:
2105: + s     - the `PetscSection`
2106: . len   - the number of components
2107: - comps - the component numbers

2109:   Output Parameter:
2110: . subs - the subsection

2112:   Level: advanced

2114:   Notes:
2115:   The chart of `subs` is the same as the chart of `s`

2117:   This will error if the section has more than one field, or if a component number is out of range

2119: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionCreateSupersection()`, `PetscSectionCreate()`
2120: @*/
2121: PetscErrorCode PetscSectionCreateComponentSubsection(PetscSection s, PetscInt len, const PetscInt comps[], PetscSection *subs)
2122: {
2123:   PetscSectionSym sym;
2124:   const char     *name = NULL;
2125:   PetscInt        Nf, pStart, pEnd;

2127:   PetscFunctionBegin;
2128:   if (!len) PetscFunctionReturn(PETSC_SUCCESS);
2130:   PetscAssertPointer(comps, 3);
2131:   PetscAssertPointer(subs, 4);
2132:   PetscCall(PetscSectionGetNumFields(s, &Nf));
2133:   PetscCheck(Nf == 1, PetscObjectComm((PetscObject)s), PETSC_ERR_ARG_WRONG, "This method can only handle one field, not %" PetscInt_FMT, Nf);
2134:   PetscCall(PetscSectionCreate(PetscObjectComm((PetscObject)s), subs));
2135:   PetscCall(PetscSectionSetNumFields(*subs, 1));
2136:   PetscCall(PetscSectionGetFieldName(s, 0, &name));
2137:   PetscCall(PetscSectionSetFieldName(*subs, 0, name));
2138:   PetscCall(PetscSectionSetFieldComponents(*subs, 0, len));
2139:   PetscCall(PetscSectionGetFieldSym(s, 0, &sym));
2140:   PetscCall(PetscSectionSetFieldSym(*subs, 0, sym));
2141:   for (PetscInt c = 0; c < len; ++c) {
2142:     PetscCall(PetscSectionGetComponentName(s, 0, comps[c], &name));
2143:     PetscCall(PetscSectionSetComponentName(*subs, 0, c, name));
2144:   }
2145:   PetscCall(PetscSectionGetChart(s, &pStart, &pEnd));
2146:   PetscCall(PetscSectionSetChart(*subs, pStart, pEnd));
2147:   for (PetscInt p = pStart; p < pEnd; ++p) {
2148:     PetscInt dof, cdof, cfdof;

2150:     PetscCall(PetscSectionGetDof(s, p, &dof));
2151:     if (!dof) continue;
2152:     PetscCall(PetscSectionGetFieldConstraintDof(s, p, 0, &cfdof));
2153:     PetscCall(PetscSectionGetConstraintDof(s, p, &cdof));
2154:     PetscCheck(!cdof && !cfdof, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Component selection does not work with constraints");
2155:     PetscCall(PetscSectionSetFieldDof(*subs, p, 0, len));
2156:     PetscCall(PetscSectionSetDof(*subs, p, len));
2157:   }
2158:   PetscCall(PetscSectionSetUp(*subs));
2159:   PetscFunctionReturn(PETSC_SUCCESS);
2160: }

2162: /*@
2163:   PetscSectionCreateSupersection - Create a new, larger section composed of multiple `PetscSection`s

2165:   Collective

2167:   Input Parameters:
2168: + s   - the input sections
2169: - len - the number of input sections

2171:   Output Parameter:
2172: . supers - the supersection

2174:   Level: advanced

2176:   Notes:
2177:   The section offsets now refer to a new, larger vector.

2179:   Developer Notes:
2180:   Needs to explain how the sections are composed

2182: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionCreateSubsection()`, `PetscSectionCreate()`
2183: @*/
2184: PetscErrorCode PetscSectionCreateSupersection(PetscSection s[], PetscInt len, PetscSection *supers)
2185: {
2186:   PetscInt Nf = 0, f, pStart = PETSC_INT_MAX, pEnd = 0, p, maxCdof = 0, i;

2188:   PetscFunctionBegin;
2189:   if (!len) PetscFunctionReturn(PETSC_SUCCESS);
2190:   for (i = 0; i < len; ++i) {
2191:     PetscInt nf, pStarti, pEndi;

2193:     PetscCall(PetscSectionGetNumFields(s[i], &nf));
2194:     PetscCall(PetscSectionGetChart(s[i], &pStarti, &pEndi));
2195:     pStart = PetscMin(pStart, pStarti);
2196:     pEnd   = PetscMax(pEnd, pEndi);
2197:     Nf += nf;
2198:   }
2199:   PetscCall(PetscSectionCreate(PetscObjectComm((PetscObject)s[0]), supers));
2200:   PetscCall(PetscSectionSetNumFields(*supers, Nf));
2201:   for (i = 0, f = 0; i < len; ++i) {
2202:     PetscInt nf, fi, ci;

2204:     PetscCall(PetscSectionGetNumFields(s[i], &nf));
2205:     for (fi = 0; fi < nf; ++fi, ++f) {
2206:       const char *name    = NULL;
2207:       PetscInt    numComp = 0;

2209:       PetscCall(PetscSectionGetFieldName(s[i], fi, &name));
2210:       PetscCall(PetscSectionSetFieldName(*supers, f, name));
2211:       PetscCall(PetscSectionGetFieldComponents(s[i], fi, &numComp));
2212:       PetscCall(PetscSectionSetFieldComponents(*supers, f, numComp));
2213:       for (ci = 0; ci < s[i]->numFieldComponents[fi]; ++ci) {
2214:         PetscCall(PetscSectionGetComponentName(s[i], fi, ci, &name));
2215:         PetscCall(PetscSectionSetComponentName(*supers, f, ci, name));
2216:       }
2217:     }
2218:   }
2219:   PetscCall(PetscSectionSetChart(*supers, pStart, pEnd));
2220:   for (p = pStart; p < pEnd; ++p) {
2221:     PetscInt dof = 0, cdof = 0;

2223:     for (i = 0, f = 0; i < len; ++i) {
2224:       PetscInt nf, fi, pStarti, pEndi;
2225:       PetscInt fdof = 0, cfdof = 0;

2227:       PetscCall(PetscSectionGetNumFields(s[i], &nf));
2228:       PetscCall(PetscSectionGetChart(s[i], &pStarti, &pEndi));
2229:       if ((p < pStarti) || (p >= pEndi)) continue;
2230:       for (fi = 0; fi < nf; ++fi, ++f) {
2231:         PetscCall(PetscSectionGetFieldDof(s[i], p, fi, &fdof));
2232:         PetscCall(PetscSectionAddFieldDof(*supers, p, f, fdof));
2233:         PetscCall(PetscSectionGetFieldConstraintDof(s[i], p, fi, &cfdof));
2234:         if (cfdof) PetscCall(PetscSectionAddFieldConstraintDof(*supers, p, f, cfdof));
2235:         dof += fdof;
2236:         cdof += cfdof;
2237:       }
2238:     }
2239:     PetscCall(PetscSectionSetDof(*supers, p, dof));
2240:     if (cdof) PetscCall(PetscSectionSetConstraintDof(*supers, p, cdof));
2241:     maxCdof = PetscMax(cdof, maxCdof);
2242:   }
2243:   PetscCall(PetscSectionSetUp(*supers));
2244:   if (maxCdof) {
2245:     PetscInt *indices;

2247:     PetscCall(PetscMalloc1(maxCdof, &indices));
2248:     for (p = pStart; p < pEnd; ++p) {
2249:       PetscInt cdof;

2251:       PetscCall(PetscSectionGetConstraintDof(*supers, p, &cdof));
2252:       if (cdof) {
2253:         PetscInt dof, numConst = 0, fOff = 0;

2255:         for (i = 0, f = 0; i < len; ++i) {
2256:           const PetscInt *oldIndices = NULL;
2257:           PetscInt        nf, fi, pStarti, pEndi, fdof, cfdof, fc;

2259:           PetscCall(PetscSectionGetNumFields(s[i], &nf));
2260:           PetscCall(PetscSectionGetChart(s[i], &pStarti, &pEndi));
2261:           if ((p < pStarti) || (p >= pEndi)) continue;
2262:           for (fi = 0; fi < nf; ++fi, ++f) {
2263:             PetscCall(PetscSectionGetFieldDof(s[i], p, fi, &fdof));
2264:             PetscCall(PetscSectionGetFieldConstraintDof(s[i], p, fi, &cfdof));
2265:             PetscCall(PetscSectionGetFieldConstraintIndices(s[i], p, fi, &oldIndices));
2266:             for (fc = 0; fc < cfdof; ++fc) indices[numConst + fc] = oldIndices[fc];
2267:             PetscCall(PetscSectionSetFieldConstraintIndices(*supers, p, f, &indices[numConst]));
2268:             for (fc = 0; fc < cfdof; ++fc) indices[numConst + fc] += fOff;
2269:             numConst += cfdof;
2270:           }
2271:           PetscCall(PetscSectionGetDof(s[i], p, &dof));
2272:           fOff += dof;
2273:         }
2274:         PetscCall(PetscSectionSetConstraintIndices(*supers, p, indices));
2275:       }
2276:     }
2277:     PetscCall(PetscFree(indices));
2278:   }
2279:   PetscFunctionReturn(PETSC_SUCCESS);
2280: }

2282: static PetscErrorCode PetscSectionCreateSubplexSection_Private(PetscSection s, IS subpointIS, PetscBool renumberPoints, PetscSection *subs)
2283: {
2284:   const PetscInt *points = NULL, *indices = NULL;
2285:   PetscInt       *spoints = NULL, *order = NULL;
2286:   PetscInt        numFields, f, c, numSubpoints = 0, pStart, pEnd, p, spStart, spEnd, subp;

2288:   PetscFunctionBegin;
2291:   PetscAssertPointer(subs, 4);
2292:   PetscCall(PetscSectionGetNumFields(s, &numFields));
2293:   PetscCall(PetscSectionCreate(PetscObjectComm((PetscObject)s), subs));
2294:   if (numFields) PetscCall(PetscSectionSetNumFields(*subs, numFields));
2295:   for (f = 0; f < numFields; ++f) {
2296:     const char *name    = NULL;
2297:     PetscInt    numComp = 0;

2299:     PetscCall(PetscSectionGetFieldName(s, f, &name));
2300:     PetscCall(PetscSectionSetFieldName(*subs, f, name));
2301:     PetscCall(PetscSectionGetFieldComponents(s, f, &numComp));
2302:     PetscCall(PetscSectionSetFieldComponents(*subs, f, numComp));
2303:     for (c = 0; c < s->numFieldComponents[f]; ++c) {
2304:       PetscCall(PetscSectionGetComponentName(s, f, c, &name));
2305:       PetscCall(PetscSectionSetComponentName(*subs, f, c, name));
2306:     }
2307:   }
2308:   /* For right now, we do not try to squeeze the subchart */
2309:   if (subpointIS) {
2310:     PetscCall(ISGetLocalSize(subpointIS, &numSubpoints));
2311:     PetscCall(ISGetIndices(subpointIS, &points));
2312:   }
2313:   PetscCall(PetscSectionGetChart(s, &pStart, &pEnd));
2314:   if (renumberPoints) {
2315:     PetscBool sorted;

2317:     spStart = 0;
2318:     spEnd   = numSubpoints;
2319:     PetscCall(ISSorted(subpointIS, &sorted));
2320:     if (!sorted) {
2321:       PetscCall(PetscMalloc2(numSubpoints, &spoints, numSubpoints, &order));
2322:       PetscCall(PetscArraycpy(spoints, points, numSubpoints));
2323:       for (PetscInt i = 0; i < numSubpoints; ++i) order[i] = i;
2324:       PetscCall(PetscSortIntWithArray(numSubpoints, spoints, order));
2325:     }
2326:   } else {
2327:     PetscCall(ISGetMinMax(subpointIS, &spStart, &spEnd));
2328:     ++spEnd;
2329:   }
2330:   PetscCall(PetscSectionSetChart(*subs, spStart, spEnd));
2331:   for (p = pStart; p < pEnd; ++p) {
2332:     PetscInt dof, cdof, fdof = 0, cfdof = 0;

2334:     PetscCall(PetscFindInt(p, numSubpoints, spoints ? spoints : points, &subp));
2335:     if (subp < 0) continue;
2336:     if (!renumberPoints) subp = p;
2337:     else subp = order ? order[subp] : subp;
2338:     for (f = 0; f < numFields; ++f) {
2339:       PetscCall(PetscSectionGetFieldDof(s, p, f, &fdof));
2340:       PetscCall(PetscSectionSetFieldDof(*subs, subp, f, fdof));
2341:       PetscCall(PetscSectionGetFieldConstraintDof(s, p, f, &cfdof));
2342:       if (cfdof) PetscCall(PetscSectionSetFieldConstraintDof(*subs, subp, f, cfdof));
2343:     }
2344:     PetscCall(PetscSectionGetDof(s, p, &dof));
2345:     PetscCall(PetscSectionSetDof(*subs, subp, dof));
2346:     PetscCall(PetscSectionGetConstraintDof(s, p, &cdof));
2347:     if (cdof) PetscCall(PetscSectionSetConstraintDof(*subs, subp, cdof));
2348:   }
2349:   PetscCall(PetscSectionSetUp(*subs));
2350:   /* Change offsets to original offsets */
2351:   for (p = pStart; p < pEnd; ++p) {
2352:     PetscInt off, foff = 0;

2354:     PetscCall(PetscFindInt(p, numSubpoints, spoints ? spoints : points, &subp));
2355:     if (subp < 0) continue;
2356:     if (!renumberPoints) subp = p;
2357:     else subp = order ? order[subp] : subp;
2358:     for (f = 0; f < numFields; ++f) {
2359:       PetscCall(PetscSectionGetFieldOffset(s, p, f, &foff));
2360:       PetscCall(PetscSectionSetFieldOffset(*subs, subp, f, foff));
2361:     }
2362:     PetscCall(PetscSectionGetOffset(s, p, &off));
2363:     PetscCall(PetscSectionSetOffset(*subs, subp, off));
2364:   }
2365:   /* Copy constraint indices */
2366:   for (subp = spStart; subp < spEnd; ++subp) {
2367:     PetscInt cdof;

2369:     PetscCall(PetscSectionGetConstraintDof(*subs, subp, &cdof));
2370:     if (cdof) {
2371:       for (f = 0; f < numFields; ++f) {
2372:         PetscCall(PetscSectionGetFieldConstraintIndices(s, points[subp - spStart], f, &indices));
2373:         PetscCall(PetscSectionSetFieldConstraintIndices(*subs, subp, f, indices));
2374:       }
2375:       PetscCall(PetscSectionGetConstraintIndices(s, points[subp - spStart], &indices));
2376:       PetscCall(PetscSectionSetConstraintIndices(*subs, subp, indices));
2377:     }
2378:   }
2379:   if (subpointIS) PetscCall(ISRestoreIndices(subpointIS, &points));
2380:   PetscCall(PetscFree2(spoints, order));
2381:   PetscFunctionReturn(PETSC_SUCCESS);
2382: }

2384: /*@
2385:   PetscSectionCreateSubmeshSection - Create a new, smaller section with support on the submesh

2387:   Collective

2389:   Input Parameters:
2390: + s          - the `PetscSection`
2391: - subpointIS - a sorted list of points in the original mesh which are in the submesh

2393:   Output Parameter:
2394: . subs - the subsection

2396:   Level: advanced

2398:   Notes:
2399:   The points are renumbered from 0, and the section offsets now refer to a new, smaller vector. That is the chart of `subs` is `[0,sizeof(subpointmap))`

2401:   Compare this with `PetscSectionCreateSubdomainSection()` that does not map the points numbers to start at zero but leaves them as before

2403:   Developer Notes:
2404:   The use of the term Submesh is confusing and needs clarification, it is not specific to meshes. It appears to be just a subset of the chart of the original `PetscSection`

2406: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionCreateSubdomainSection()`, `PetscSectionCreateSubsection()`, `DMPlexGetSubpointMap()`, `PetscSectionCreate()`
2407: @*/
2408: PetscErrorCode PetscSectionCreateSubmeshSection(PetscSection s, IS subpointIS, PetscSection *subs)
2409: {
2410:   PetscFunctionBegin;
2411:   PetscCall(PetscSectionCreateSubplexSection_Private(s, subpointIS, PETSC_TRUE, subs));
2412:   PetscFunctionReturn(PETSC_SUCCESS);
2413: }

2415: /*@
2416:   PetscSectionCreateSubdomainSection - Create a new, smaller section with support on a subdomain of the mesh

2418:   Collective

2420:   Input Parameters:
2421: + s           - the `PetscSection`
2422: - subpointMap - a sorted list of points in the original mesh which are in the subdomain

2424:   Output Parameter:
2425: . subs - the subsection

2427:   Level: advanced

2429:   Notes:
2430:   The point numbers remain the same as in the larger `PetscSection`, but the section offsets now refer to a new, smaller vector. The chart of `subs`
2431:   is `[min(subpointMap),max(subpointMap)+1)`

2433:   Compare this with `PetscSectionCreateSubmeshSection()` that maps the point numbers to start at zero

2435:   Developer Notes:
2436:   The use of the term Subdomain is unneeded and needs clarification, it is not specific to meshes. It appears to be just a subset of the chart of the original `PetscSection`

2438: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionCreateSubmeshSection()`, `PetscSectionCreateSubsection()`, `DMPlexGetSubpointMap()`, `PetscSectionCreate()`
2439: @*/
2440: PetscErrorCode PetscSectionCreateSubdomainSection(PetscSection s, IS subpointMap, PetscSection *subs)
2441: {
2442:   PetscFunctionBegin;
2443:   PetscCall(PetscSectionCreateSubplexSection_Private(s, subpointMap, PETSC_FALSE, subs));
2444:   PetscFunctionReturn(PETSC_SUCCESS);
2445: }

2447: static PetscErrorCode PetscSectionView_ASCII(PetscSection s, PetscViewer viewer)
2448: {
2449:   PetscInt    p;
2450:   PetscMPIInt rank;

2452:   PetscFunctionBegin;
2453:   PetscCallMPI(MPI_Comm_rank(PetscObjectComm((PetscObject)viewer), &rank));
2454:   PetscCall(PetscViewerASCIIPushSynchronized(viewer));
2455:   PetscCall(PetscViewerASCIISynchronizedPrintf(viewer, "Process %d:\n", rank));
2456:   for (p = 0; p < s->pEnd - s->pStart; ++p) {
2457:     if (s->bc && s->bc->atlasDof[p] > 0) {
2458:       PetscInt b;
2459:       PetscCall(PetscViewerASCIISynchronizedPrintf(viewer, "  (%4" PetscInt_FMT ") dof %2" PetscInt_FMT " offset %3" PetscInt_FMT " constrained", p + s->pStart, s->atlasDof[p], s->atlasOff[p]));
2460:       if (s->bcIndices) {
2461:         for (b = 0; b < s->bc->atlasDof[p]; ++b) PetscCall(PetscViewerASCIISynchronizedPrintf(viewer, " %" PetscInt_FMT, s->bcIndices[s->bc->atlasOff[p] + b]));
2462:       }
2463:       PetscCall(PetscViewerASCIISynchronizedPrintf(viewer, "\n"));
2464:     } else {
2465:       PetscCall(PetscViewerASCIISynchronizedPrintf(viewer, "  (%4" PetscInt_FMT ") dof %2" PetscInt_FMT " offset %3" PetscInt_FMT "\n", p + s->pStart, s->atlasDof[p], s->atlasOff[p]));
2466:     }
2467:   }
2468:   PetscCall(PetscViewerFlush(viewer));
2469:   PetscCall(PetscViewerASCIIPopSynchronized(viewer));
2470:   if (s->sym) {
2471:     PetscCall(PetscViewerASCIIPushTab(viewer));
2472:     PetscCall(PetscSectionSymView(s->sym, viewer));
2473:     PetscCall(PetscViewerASCIIPopTab(viewer));
2474:   }
2475:   PetscFunctionReturn(PETSC_SUCCESS);
2476: }

2478: /*@
2479:   PetscSectionViewFromOptions - View the `PetscSection` based on values in the options database

2481:   Collective

2483:   Input Parameters:
2484: + A    - the `PetscSection` object to view
2485: . obj  - Optional object that provides the options prefix used for the options
2486: - name - command line option

2488:   Level: intermediate

2490:   Note:
2491:   See `PetscObjectViewFromOptions()` for available values of `PetscViewer` and `PetscViewerFormat`

2493: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionView`, `PetscObjectViewFromOptions()`, `PetscSectionCreate()`, `PetscSectionView()`
2494: @*/
2495: PetscErrorCode PetscSectionViewFromOptions(PetscSection A, PetscObject obj, const char name[])
2496: {
2497:   PetscFunctionBegin;
2499:   PetscCall(PetscObjectViewFromOptions((PetscObject)A, obj, name));
2500:   PetscFunctionReturn(PETSC_SUCCESS);
2501: }

2503: /*@
2504:   PetscSectionView - Views a `PetscSection`

2506:   Collective

2508:   Input Parameters:
2509: + s      - the `PetscSection` object to view
2510: - viewer - the viewer

2512:   Level: beginner

2514:   Note:
2515:   `PetscSectionView()`, when viewer is of type `PETSCVIEWERHDF5`, only saves
2516:   distribution independent data, such as dofs, offsets, constraint dofs,
2517:   and constraint indices. Points that have negative dofs, for instance,
2518:   are not saved as they represent points owned by other processes.
2519:   Point numbering and rank assignment is currently not stored.
2520:   The saved section can be loaded with `PetscSectionLoad()`.

2522: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionCreate()`, `PetscSectionDestroy()`, `PetscSectionLoad()`, `PetscViewer`
2523: @*/
2524: PetscErrorCode PetscSectionView(PetscSection s, PetscViewer viewer)
2525: {
2526:   PetscBool isascii, ishdf5;
2527:   PetscInt  f;

2529:   PetscFunctionBegin;
2531:   if (!viewer) PetscCall(PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)s), &viewer));
2533:   PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERASCII, &isascii));
2534:   PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERHDF5, &ishdf5));
2535:   if (isascii) {
2536:     PetscCall(PetscObjectPrintClassNamePrefixType((PetscObject)s, viewer));
2537:     if (s->numFields) {
2538:       PetscCall(PetscViewerASCIIPrintf(viewer, "%" PetscInt_FMT " fields\n", s->numFields));
2539:       for (f = 0; f < s->numFields; ++f) {
2540:         PetscCall(PetscViewerASCIIPrintf(viewer, "  field %" PetscInt_FMT " \"%s\" with %" PetscInt_FMT " components\n", f, s->fieldNames[f], s->numFieldComponents[f]));
2541:         PetscCall(PetscSectionView_ASCII(s->field[f], viewer));
2542:       }
2543:     } else {
2544:       PetscCall(PetscSectionView_ASCII(s, viewer));
2545:     }
2546:   } else if (ishdf5) {
2547: #if PetscDefined(HAVE_HDF5)
2548:     PetscCall(PetscSectionView_HDF5_Internal(s, viewer));
2549: #else
2550:     SETERRQ(PetscObjectComm((PetscObject)s), PETSC_ERR_SUP, "HDF5 not supported in this build.\nPlease reconfigure using --download-hdf5");
2551: #endif
2552:   }
2553:   PetscFunctionReturn(PETSC_SUCCESS);
2554: }

2556: /*@
2557:   PetscSectionLoad - Loads a `PetscSection`

2559:   Collective

2561:   Input Parameters:
2562: + s      - the `PetscSection` object to load
2563: - viewer - the viewer

2565:   Level: beginner

2567:   Note:
2568:   `PetscSectionLoad()`, when viewer is of type `PETSCVIEWERHDF5`, loads
2569:   a section saved with `PetscSectionView()`. The number of processes
2570:   used here (N) does not need to be the same as that used when saving.
2571:   After calling this function, the chart of s on rank i will be set
2572:   to [0, E_i), where \sum_{i=0}^{N-1}E_i equals to the total number of
2573:   saved section points.

2575: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionCreate()`, `PetscSectionDestroy()`, `PetscSectionView()`
2576: @*/
2577: PetscErrorCode PetscSectionLoad(PetscSection s, PetscViewer viewer)
2578: {
2579:   PetscBool ishdf5;

2581:   PetscFunctionBegin;
2584:   PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERHDF5, &ishdf5));
2585:   if (ishdf5) {
2586: #if PetscDefined(HAVE_HDF5)
2587:     PetscCall(PetscSectionLoad_HDF5_Internal(s, viewer));
2588:     PetscFunctionReturn(PETSC_SUCCESS);
2589: #else
2590:     SETERRQ(PetscObjectComm((PetscObject)s), PETSC_ERR_SUP, "HDF5 not supported in this build.\nPlease reconfigure using --download-hdf5");
2591: #endif
2592:   } else SETERRQ(PetscObjectComm((PetscObject)s), PETSC_ERR_SUP, "Viewer type %s not yet supported for PetscSection loading", ((PetscObject)viewer)->type_name);
2593: }

2595: /*@
2596:   PetscSectionResetClosurePermutation - Remove any existing closure permutation

2598:   Input Parameter:
2599: . section - The `PetscSection`

2601:   Level: intermediate

2603: .seealso: `PetscSectionSetClosurePermutation()`, `PetscSectionSetClosureIndex()`, `PetscSectionReset()`
2604: @*/
2605: PetscErrorCode PetscSectionResetClosurePermutation(PetscSection section)
2606: {
2607:   PetscSectionClosurePermVal clVal;

2609:   PetscFunctionBegin;
2610:   if (!section->clHash) PetscFunctionReturn(PETSC_SUCCESS);
2611:   kh_foreach_value(section->clHash, clVal, {
2612:     PetscCall(PetscFree(clVal.perm));
2613:     PetscCall(PetscFree(clVal.invPerm));
2614:   });
2615:   kh_destroy(ClPerm, section->clHash);
2616:   section->clHash = NULL;
2617:   PetscFunctionReturn(PETSC_SUCCESS);
2618: }

2620: /*@
2621:   PetscSectionReset - Frees all section data, the section is then as if `PetscSectionCreate()` had just been called.

2623:   Not Collective

2625:   Input Parameter:
2626: . s - the `PetscSection`

2628:   Level: beginner

2630: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionCreate()`
2631: @*/
2632: PetscErrorCode PetscSectionReset(PetscSection s)
2633: {
2634:   PetscInt f, c;

2636:   PetscFunctionBegin;
2638:   for (f = 0; f < s->numFields; ++f) {
2639:     PetscCall(PetscSectionDestroy(&s->field[f]));
2640:     PetscCall(PetscFree(s->fieldNames[f]));
2641:     for (c = 0; c < s->numFieldComponents[f]; ++c) PetscCall(PetscFree(s->compNames[f][c]));
2642:     PetscCall(PetscFree(s->compNames[f]));
2643:   }
2644:   PetscCall(PetscFree(s->numFieldComponents));
2645:   PetscCall(PetscFree(s->fieldNames));
2646:   PetscCall(PetscFree(s->compNames));
2647:   PetscCall(PetscFree(s->field));
2648:   PetscCall(PetscSectionDestroy(&s->bc));
2649:   PetscCall(PetscFree(s->bcIndices));
2650:   PetscCall(PetscFree2(s->atlasDof, s->atlasOff));
2651:   PetscCall(PetscSectionDestroy(&s->clSection));
2652:   PetscCall(ISDestroy(&s->clPoints));
2653:   PetscCall(ISDestroy(&s->perm));
2654:   PetscCall(PetscBTDestroy(&s->blockStarts));
2655:   PetscCall(PetscSectionResetClosurePermutation(s));
2656:   PetscCall(PetscSectionSymDestroy(&s->sym));
2657:   PetscCall(PetscSectionDestroy(&s->clSection));
2658:   PetscCall(ISDestroy(&s->clPoints));
2659:   PetscCall(PetscSectionInvalidateMaxDof_Internal(s));
2660:   s->pStart    = -1;
2661:   s->pEnd      = -1;
2662:   s->maxDof    = 0;
2663:   s->setup     = PETSC_FALSE;
2664:   s->numFields = 0;
2665:   s->clObj     = NULL;
2666:   PetscFunctionReturn(PETSC_SUCCESS);
2667: }

2669: /*@
2670:   PetscSectionDestroy - Frees a `PetscSection`

2672:   Not Collective

2674:   Input Parameter:
2675: . s - the `PetscSection`

2677:   Level: beginner

2679: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionCreate()`, `PetscSectionReset()`
2680: @*/
2681: PetscErrorCode PetscSectionDestroy(PetscSection *s)
2682: {
2683:   PetscFunctionBegin;
2684:   if (!*s) PetscFunctionReturn(PETSC_SUCCESS);
2686:   if (--((PetscObject)*s)->refct > 0) {
2687:     *s = NULL;
2688:     PetscFunctionReturn(PETSC_SUCCESS);
2689:   }
2690:   PetscCall(PetscSectionReset(*s));
2691:   PetscCall(PetscHeaderDestroy(s));
2692:   PetscFunctionReturn(PETSC_SUCCESS);
2693: }

2695: static PetscErrorCode VecIntGetValuesSection_Private(const PetscInt *baseArray, PetscSection s, PetscInt point, const PetscInt **values)
2696: {
2697:   const PetscInt p = point - s->pStart;

2699:   PetscFunctionBegin;
2701:   *values = &baseArray[s->atlasOff[p]];
2702:   PetscFunctionReturn(PETSC_SUCCESS);
2703: }

2705: static PetscErrorCode VecIntSetValuesSection_Private(PetscInt *baseArray, PetscSection s, PetscInt point, const PetscInt values[], InsertMode mode)
2706: {
2707:   PetscInt      *array;
2708:   const PetscInt p           = point - s->pStart;
2709:   const PetscInt orientation = 0; /* Needs to be included for use in closure operations */
2710:   PetscInt       cDim        = 0;

2712:   PetscFunctionBegin;
2714:   PetscCall(PetscSectionGetConstraintDof(s, p, &cDim));
2715:   array = &baseArray[s->atlasOff[p]];
2716:   if (!cDim) {
2717:     if (orientation >= 0) {
2718:       const PetscInt dim = s->atlasDof[p];
2719:       PetscInt       i;

2721:       if (mode == INSERT_VALUES) {
2722:         for (i = 0; i < dim; ++i) array[i] = values ? values[i] : i;
2723:       } else {
2724:         for (i = 0; i < dim; ++i) array[i] += values[i];
2725:       }
2726:     } else {
2727:       PetscInt offset = 0;
2728:       PetscInt j      = -1, field, i;

2730:       for (field = 0; field < s->numFields; ++field) {
2731:         const PetscInt dim = s->field[field]->atlasDof[p];

2733:         for (i = dim - 1; i >= 0; --i) array[++j] = values ? values[i + offset] : i + offset;
2734:         offset += dim;
2735:       }
2736:     }
2737:   } else {
2738:     if (orientation >= 0) {
2739:       const PetscInt  dim  = s->atlasDof[p];
2740:       PetscInt        cInd = 0, i;
2741:       const PetscInt *cDof;

2743:       PetscCall(PetscSectionGetConstraintIndices(s, point, &cDof));
2744:       if (mode == INSERT_VALUES) {
2745:         for (i = 0; i < dim; ++i) {
2746:           if ((cInd < cDim) && (i == cDof[cInd])) {
2747:             ++cInd;
2748:             continue;
2749:           }
2750:           array[i] = values ? values[i] : i;
2751:         }
2752:       } else {
2753:         for (i = 0; i < dim; ++i) {
2754:           if ((cInd < cDim) && (i == cDof[cInd])) {
2755:             ++cInd;
2756:             continue;
2757:           }
2758:           array[i] += values[i];
2759:         }
2760:       }
2761:     } else {
2762:       const PetscInt *cDof;
2763:       PetscInt        offset  = 0;
2764:       PetscInt        cOffset = 0;
2765:       PetscInt        j       = 0, field;

2767:       PetscCall(PetscSectionGetConstraintIndices(s, point, &cDof));
2768:       for (field = 0; field < s->numFields; ++field) {
2769:         const PetscInt dim  = s->field[field]->atlasDof[p];     /* PetscSectionGetFieldDof() */
2770:         const PetscInt tDim = s->field[field]->bc->atlasDof[p]; /* PetscSectionGetFieldConstraintDof() */
2771:         const PetscInt sDim = dim - tDim;
2772:         PetscInt       cInd = 0, i, k;

2774:         for (i = 0, k = dim + offset - 1; i < dim; ++i, ++j, --k) {
2775:           if ((cInd < sDim) && (j == cDof[cInd + cOffset])) {
2776:             ++cInd;
2777:             continue;
2778:           }
2779:           array[j] = values ? values[k] : k;
2780:         }
2781:         offset += dim;
2782:         cOffset += dim - tDim;
2783:       }
2784:     }
2785:   }
2786:   PetscFunctionReturn(PETSC_SUCCESS);
2787: }

2789: /*@
2790:   PetscSectionHasConstraints - Determine whether a `PetscSection` has constrained dofs

2792:   Not Collective

2794:   Input Parameter:
2795: . s - The `PetscSection`

2797:   Output Parameter:
2798: . hasConstraints - flag indicating that the section has constrained dofs

2800:   Level: intermediate

2802: .seealso: [PetscSection](sec_petscsection), `PetscSectionSetConstraintIndices()`, `PetscSectionGetConstraintDof()`, `PetscSection`
2803: @*/
2804: PetscErrorCode PetscSectionHasConstraints(PetscSection s, PetscBool *hasConstraints)
2805: {
2806:   PetscFunctionBegin;
2808:   PetscAssertPointer(hasConstraints, 2);
2809:   *hasConstraints = s->bc ? PETSC_TRUE : PETSC_FALSE;
2810:   PetscFunctionReturn(PETSC_SUCCESS);
2811: }

2813: /*@C
2814:   PetscSectionGetConstraintIndices - Get the point dof numbers, in [0, dof), which are constrained for a given point

2816:   Not Collective

2818:   Input Parameters:
2819: + s     - The `PetscSection`
2820: - point - The point

2822:   Output Parameter:
2823: . indices - The constrained dofs

2825:   Level: intermediate

2827:   Fortran Notes:
2828:   Use `PetscSectionGetConstraintIndicesF90()` and `PetscSectionRestoreConstraintIndicesF90()`

2830: .seealso: [PetscSection](sec_petscsection), `PetscSectionSetConstraintIndices()`, `PetscSectionGetConstraintDof()`, `PetscSection`
2831: @*/
2832: PetscErrorCode PetscSectionGetConstraintIndices(PetscSection s, PetscInt point, const PetscInt *indices[])
2833: {
2834:   PetscFunctionBegin;
2836:   if (s->bc) {
2837:     PetscCall(VecIntGetValuesSection_Private(s->bcIndices, s->bc, point, indices));
2838:   } else *indices = NULL;
2839:   PetscFunctionReturn(PETSC_SUCCESS);
2840: }

2842: /*@
2843:   PetscSectionSetConstraintIndices - Set the point dof numbers, in [0, dof), which are constrained

2845:   Not Collective

2847:   Input Parameters:
2848: + s       - The `PetscSection`
2849: . point   - The point
2850: - indices - The constrained dofs

2852:   Level: intermediate

2854:   Fortran Notes:
2855:   Use `PetscSectionSetConstraintIndicesF90()`

2857: .seealso: [PetscSection](sec_petscsection), `PetscSectionGetConstraintIndices()`, `PetscSectionGetConstraintDof()`, `PetscSection`
2858: @*/
2859: PetscErrorCode PetscSectionSetConstraintIndices(PetscSection s, PetscInt point, const PetscInt indices[])
2860: {
2861:   PetscFunctionBegin;
2863:   if (s->bc) {
2864:     const PetscInt dof  = s->atlasDof[point];
2865:     const PetscInt cdof = s->bc->atlasDof[point];
2866:     PetscInt       d;

2868:     if (indices)
2869:       for (d = 0; d < cdof; ++d) PetscCheck(indices[d] < dof, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Point %" PetscInt_FMT " dof %" PetscInt_FMT ", invalid constraint index[%" PetscInt_FMT "]: %" PetscInt_FMT, point, dof, d, indices[d]);
2870:     PetscCall(VecIntSetValuesSection_Private(s->bcIndices, s->bc, point, indices, INSERT_VALUES));
2871:   }
2872:   PetscFunctionReturn(PETSC_SUCCESS);
2873: }

2875: /*@C
2876:   PetscSectionGetFieldConstraintIndices - Get the field dof numbers, in [0, fdof), which are constrained

2878:   Not Collective

2880:   Input Parameters:
2881: + s     - The `PetscSection`
2882: . field - The field number
2883: - point - The point

2885:   Output Parameter:
2886: . indices - The constrained dofs sorted in ascending order

2888:   Level: intermediate

2890:   Note:
2891:   The indices array, which is provided by the caller, must have capacity to hold the number of constrained dofs, e.g., as returned by `PetscSectionGetConstraintDof()`.

2893:   Fortran Notes:
2894:   Use `PetscSectionGetFieldConstraintIndicesF90()` and `PetscSectionRestoreFieldConstraintIndicesF90()`

2896: .seealso: [PetscSection](sec_petscsection), `PetscSectionSetFieldConstraintIndices()`, `PetscSectionGetConstraintIndices()`, `PetscSectionGetConstraintDof()`, `PetscSection`
2897: @*/
2898: PetscErrorCode PetscSectionGetFieldConstraintIndices(PetscSection s, PetscInt point, PetscInt field, const PetscInt **indices)
2899: {
2900:   PetscFunctionBegin;
2902:   PetscAssertPointer(indices, 4);
2903:   PetscSectionCheckValidField(field, s->numFields);
2904:   PetscCall(PetscSectionGetConstraintIndices(s->field[field], point, indices));
2905:   PetscFunctionReturn(PETSC_SUCCESS);
2906: }

2908: /*@C
2909:   PetscSectionSetFieldConstraintIndices - Set the field dof numbers, in [0, fdof), which are constrained

2911:   Not Collective

2913:   Input Parameters:
2914: + s       - The `PetscSection`
2915: . point   - The point
2916: . field   - The field number
2917: - indices - The constrained dofs

2919:   Level: intermediate

2921:   Fortran Notes:
2922:   Use `PetscSectionSetFieldConstraintIndicesF90()`

2924: .seealso: [PetscSection](sec_petscsection), `PetscSectionSetConstraintIndices()`, `PetscSectionGetFieldConstraintIndices()`, `PetscSectionGetConstraintDof()`, `PetscSection`
2925: @*/
2926: PetscErrorCode PetscSectionSetFieldConstraintIndices(PetscSection s, PetscInt point, PetscInt field, const PetscInt indices[])
2927: {
2928:   PetscFunctionBegin;
2930:   PetscSectionCheckValidField(field, s->numFields);
2931:   PetscCall(PetscSectionSetConstraintIndices(s->field[field], point, indices));
2932:   PetscFunctionReturn(PETSC_SUCCESS);
2933: }

2935: /*@
2936:   PetscSectionPermute - Reorder the section according to the input point permutation

2938:   Collective

2940:   Input Parameters:
2941: + section     - The `PetscSection` object
2942: - permutation - The point permutation, old point p becomes new point perm[p]

2944:   Output Parameter:
2945: . sectionNew - The permuted `PetscSection`

2947:   Level: intermediate

2949:   Note:
2950:   The data and the access to the data via `PetscSectionGetFieldOffset()` and `PetscSectionGetOffset()` are both changed in `sectionNew`

2952:   Compare to `PetscSectionSetPermutation()`

2954: .seealso: [PetscSection](sec_petscsection), `IS`, `PetscSection`, `MatPermute()`, `PetscSectionSetPermutation()`
2955: @*/
2956: PetscErrorCode PetscSectionPermute(PetscSection section, IS permutation, PetscSection *sectionNew)
2957: {
2958:   PetscSection    s = section, sNew;
2959:   const PetscInt *perm;
2960:   PetscInt        numFields, f, c, numPoints, pStart, pEnd, p;

2962:   PetscFunctionBegin;
2965:   PetscAssertPointer(sectionNew, 3);
2966:   PetscCall(PetscSectionCreate(PetscObjectComm((PetscObject)s), &sNew));
2967:   PetscCall(PetscSectionGetNumFields(s, &numFields));
2968:   if (numFields) PetscCall(PetscSectionSetNumFields(sNew, numFields));
2969:   for (f = 0; f < numFields; ++f) {
2970:     const char *name;
2971:     PetscInt    numComp;

2973:     PetscCall(PetscSectionGetFieldName(s, f, &name));
2974:     PetscCall(PetscSectionSetFieldName(sNew, f, name));
2975:     PetscCall(PetscSectionGetFieldComponents(s, f, &numComp));
2976:     PetscCall(PetscSectionSetFieldComponents(sNew, f, numComp));
2977:     for (c = 0; c < s->numFieldComponents[f]; ++c) {
2978:       PetscCall(PetscSectionGetComponentName(s, f, c, &name));
2979:       PetscCall(PetscSectionSetComponentName(sNew, f, c, name));
2980:     }
2981:   }
2982:   PetscCall(ISGetLocalSize(permutation, &numPoints));
2983:   PetscCall(ISGetIndices(permutation, &perm));
2984:   PetscCall(PetscSectionGetChart(s, &pStart, &pEnd));
2985:   PetscCall(PetscSectionSetChart(sNew, pStart, pEnd));
2986:   PetscCheck(numPoints >= pEnd, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Permutation size %" PetscInt_FMT " is less than largest Section point %" PetscInt_FMT, numPoints, pEnd);
2987:   for (p = pStart; p < pEnd; ++p) {
2988:     PetscInt dof, cdof;

2990:     PetscCall(PetscSectionGetDof(s, p, &dof));
2991:     PetscCall(PetscSectionSetDof(sNew, perm[p], dof));
2992:     PetscCall(PetscSectionGetConstraintDof(s, p, &cdof));
2993:     if (cdof) PetscCall(PetscSectionSetConstraintDof(sNew, perm[p], cdof));
2994:     for (f = 0; f < numFields; ++f) {
2995:       PetscCall(PetscSectionGetFieldDof(s, p, f, &dof));
2996:       PetscCall(PetscSectionSetFieldDof(sNew, perm[p], f, dof));
2997:       PetscCall(PetscSectionGetFieldConstraintDof(s, p, f, &cdof));
2998:       if (cdof) PetscCall(PetscSectionSetFieldConstraintDof(sNew, perm[p], f, cdof));
2999:     }
3000:   }
3001:   PetscCall(PetscSectionSetUp(sNew));
3002:   for (p = pStart; p < pEnd; ++p) {
3003:     const PetscInt *cind;
3004:     PetscInt        cdof;

3006:     PetscCall(PetscSectionGetConstraintDof(s, p, &cdof));
3007:     if (cdof) {
3008:       PetscCall(PetscSectionGetConstraintIndices(s, p, &cind));
3009:       PetscCall(PetscSectionSetConstraintIndices(sNew, perm[p], cind));
3010:     }
3011:     for (f = 0; f < numFields; ++f) {
3012:       PetscCall(PetscSectionGetFieldConstraintDof(s, p, f, &cdof));
3013:       if (cdof) {
3014:         PetscCall(PetscSectionGetFieldConstraintIndices(s, p, f, &cind));
3015:         PetscCall(PetscSectionSetFieldConstraintIndices(sNew, perm[p], f, cind));
3016:       }
3017:     }
3018:   }
3019:   PetscCall(ISRestoreIndices(permutation, &perm));
3020:   *sectionNew = sNew;
3021:   PetscFunctionReturn(PETSC_SUCCESS);
3022: }

3024: /*@
3025:   PetscSectionSetClosureIndex - Create an internal data structure to speed up closure queries.

3027:   Collective

3029:   Input Parameters:
3030: + section   - The `PetscSection`
3031: . obj       - A `PetscObject` which serves as the key for this index
3032: . clSection - `PetscSection` giving the size of the closure of each point
3033: - clPoints  - `IS` giving the points in each closure

3035:   Level: advanced

3037:   Note:
3038:   This function creates an internal map from each point to its closure. We compress out closure points with no dofs in this section.

3040:   Developer Notes:
3041:   The information provided here is completely opaque

3043: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionGetClosureIndex()`, `DMPlexCreateClosureIndex()`
3044: @*/
3045: PetscErrorCode PetscSectionSetClosureIndex(PetscSection section, PetscObject obj, PetscSection clSection, IS clPoints)
3046: {
3047:   PetscFunctionBegin;
3051:   if (section->clObj != obj) PetscCall(PetscSectionResetClosurePermutation(section));
3052:   section->clObj = obj;
3053:   PetscCall(PetscObjectReference((PetscObject)clSection));
3054:   PetscCall(PetscObjectReference((PetscObject)clPoints));
3055:   PetscCall(PetscSectionDestroy(&section->clSection));
3056:   PetscCall(ISDestroy(&section->clPoints));
3057:   section->clSection = clSection;
3058:   section->clPoints  = clPoints;
3059:   PetscFunctionReturn(PETSC_SUCCESS);
3060: }

3062: /*@
3063:   PetscSectionGetClosureIndex - Get the cache of points in the closure of each point in the section set with `PetscSectionSetClosureIndex()`

3065:   Collective

3067:   Input Parameters:
3068: + section - The `PetscSection`
3069: - obj     - A `PetscObject` which serves as the key for this index

3071:   Output Parameters:
3072: + clSection - `PetscSection` giving the size of the closure of each point
3073: - clPoints  - `IS` giving the points in each closure

3075:   Level: advanced

3077: .seealso: [PetscSection](sec_petscsection), `PetscSectionSetClosureIndex()`, `DMPlexCreateClosureIndex()`
3078: @*/
3079: PetscErrorCode PetscSectionGetClosureIndex(PetscSection section, PetscObject obj, PetscSection *clSection, IS *clPoints)
3080: {
3081:   PetscFunctionBegin;
3082:   if (section->clObj == obj) {
3083:     if (clSection) *clSection = section->clSection;
3084:     if (clPoints) *clPoints = section->clPoints;
3085:   } else {
3086:     if (clSection) *clSection = NULL;
3087:     if (clPoints) *clPoints = NULL;
3088:   }
3089:   PetscFunctionReturn(PETSC_SUCCESS);
3090: }

3092: PetscErrorCode PetscSectionSetClosurePermutation_Internal(PetscSection section, PetscObject obj, PetscInt depth, PetscInt clSize, PetscCopyMode mode, PetscInt *clPerm)
3093: {
3094:   PetscInt                    i;
3095:   khiter_t                    iter;
3096:   int                         new_entry;
3097:   PetscSectionClosurePermKey  key = {depth, clSize};
3098:   PetscSectionClosurePermVal *val;

3100:   PetscFunctionBegin;
3101:   if (section->clObj != obj) {
3102:     PetscCall(PetscSectionDestroy(&section->clSection));
3103:     PetscCall(ISDestroy(&section->clPoints));
3104:   }
3105:   section->clObj = obj;
3106:   if (!section->clHash) PetscCall(PetscClPermCreate(&section->clHash));
3107:   iter = kh_put(ClPerm, section->clHash, key, &new_entry);
3108:   val  = &kh_val(section->clHash, iter);
3109:   if (!new_entry) {
3110:     PetscCall(PetscFree(val->perm));
3111:     PetscCall(PetscFree(val->invPerm));
3112:   }
3113:   if (mode == PETSC_COPY_VALUES) {
3114:     PetscCall(PetscMalloc1(clSize, &val->perm));
3115:     PetscCall(PetscArraycpy(val->perm, clPerm, clSize));
3116:   } else if (mode == PETSC_OWN_POINTER) {
3117:     val->perm = clPerm;
3118:   } else SETERRQ(PetscObjectComm(obj), PETSC_ERR_SUP, "Do not support borrowed arrays");
3119:   PetscCall(PetscMalloc1(clSize, &val->invPerm));
3120:   for (i = 0; i < clSize; ++i) val->invPerm[clPerm[i]] = i;
3121:   PetscFunctionReturn(PETSC_SUCCESS);
3122: }

3124: /*@
3125:   PetscSectionSetClosurePermutation - Set the dof permutation for the closure of each cell in the section, meaning clPerm[newIndex] = oldIndex.

3127:   Not Collective

3129:   Input Parameters:
3130: + section - The `PetscSection`
3131: . obj     - A `PetscObject` which serves as the key for this index (usually a `DM`)
3132: . depth   - Depth of points on which to apply the given permutation
3133: - perm    - Permutation of the cell dof closure

3135:   Level: intermediate

3137:   Notes:
3138:   The specified permutation will only be applied to points at depth whose closure size matches the length of perm.  In a
3139:   mixed-topology or variable-degree finite element space, this function can be called multiple times at each depth for
3140:   each topology and degree.

3142:   This approach assumes that (depth, len(perm)) uniquely identifies the desired permutation; this might not be true for
3143:   exotic/enriched spaces on mixed topology meshes.

3145: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `IS`, `PetscSectionGetClosurePermutation()`, `PetscSectionGetClosureIndex()`, `DMPlexCreateClosureIndex()`, `PetscCopyMode`
3146: @*/
3147: PetscErrorCode PetscSectionSetClosurePermutation(PetscSection section, PetscObject obj, PetscInt depth, IS perm)
3148: {
3149:   const PetscInt *clPerm = NULL;
3150:   PetscInt        clSize = 0;

3152:   PetscFunctionBegin;
3153:   if (perm) {
3154:     PetscCall(ISGetLocalSize(perm, &clSize));
3155:     PetscCall(ISGetIndices(perm, &clPerm));
3156:   }
3157:   PetscCall(PetscSectionSetClosurePermutation_Internal(section, obj, depth, clSize, PETSC_COPY_VALUES, (PetscInt *)clPerm));
3158:   if (perm) PetscCall(ISRestoreIndices(perm, &clPerm));
3159:   PetscFunctionReturn(PETSC_SUCCESS);
3160: }

3162: static PetscErrorCode PetscSectionGetClosurePermutation_Private(PetscSection section, PetscObject obj, PetscInt depth, PetscInt size, const PetscInt *perm[])
3163: {
3164:   PetscFunctionBegin;
3165:   if (section->clObj == obj) {
3166:     PetscSectionClosurePermKey k = {depth, size};
3167:     PetscSectionClosurePermVal v;

3169:     PetscCall(PetscClPermGet(section->clHash, k, &v));
3170:     if (perm) *perm = v.perm;
3171:   } else {
3172:     if (perm) *perm = NULL;
3173:   }
3174:   PetscFunctionReturn(PETSC_SUCCESS);
3175: }

3177: /*@
3178:   PetscSectionGetClosurePermutation - Get the dof permutation for the closure of each cell in the section, meaning clPerm[newIndex] = oldIndex.

3180:   Not Collective

3182:   Input Parameters:
3183: + section - The `PetscSection`
3184: . obj     - A `PetscObject` which serves as the key for this index (usually a DM)
3185: . depth   - Depth stratum on which to obtain closure permutation
3186: - clSize  - Closure size to be permuted (e.g., may vary with element topology and degree)

3188:   Output Parameter:
3189: . perm - The dof closure permutation

3191:   Level: intermediate

3193:   Note:
3194:   The user must destroy the `IS` that is returned.

3196: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `IS`, `PetscSectionSetClosurePermutation()`, `PetscSectionGetClosureInversePermutation()`, `PetscSectionGetClosureIndex()`, `PetscSectionSetClosureIndex()`, `DMPlexCreateClosureIndex()`
3197: @*/
3198: PetscErrorCode PetscSectionGetClosurePermutation(PetscSection section, PetscObject obj, PetscInt depth, PetscInt clSize, IS *perm)
3199: {
3200:   const PetscInt *clPerm = NULL;

3202:   PetscFunctionBegin;
3203:   PetscCall(PetscSectionGetClosurePermutation_Private(section, obj, depth, clSize, &clPerm));
3204:   PetscCheck(clPerm, PetscObjectComm((PetscObject)obj), PETSC_ERR_ARG_WRONG, "There is no closure permutation associated with this object for depth %" PetscInt_FMT " of size %" PetscInt_FMT, depth, clSize);
3205:   PetscCall(ISCreateGeneral(PETSC_COMM_SELF, clSize, clPerm, PETSC_USE_POINTER, perm));
3206:   PetscFunctionReturn(PETSC_SUCCESS);
3207: }

3209: PetscErrorCode PetscSectionGetClosureInversePermutation_Internal(PetscSection section, PetscObject obj, PetscInt depth, PetscInt size, const PetscInt *perm[])
3210: {
3211:   PetscFunctionBegin;
3212:   if (section->clObj == obj && section->clHash) {
3213:     PetscSectionClosurePermKey k = {depth, size};
3214:     PetscSectionClosurePermVal v;
3215:     PetscCall(PetscClPermGet(section->clHash, k, &v));
3216:     if (perm) *perm = v.invPerm;
3217:   } else {
3218:     if (perm) *perm = NULL;
3219:   }
3220:   PetscFunctionReturn(PETSC_SUCCESS);
3221: }

3223: /*@
3224:   PetscSectionGetClosureInversePermutation - Get the inverse dof permutation for the closure of each cell in the section, meaning clPerm[oldIndex] = newIndex.

3226:   Not Collective

3228:   Input Parameters:
3229: + section - The `PetscSection`
3230: . obj     - A `PetscObject` which serves as the key for this index (usually a `DM`)
3231: . depth   - Depth stratum on which to obtain closure permutation
3232: - clSize  - Closure size to be permuted (e.g., may vary with element topology and degree)

3234:   Output Parameter:
3235: . perm - The dof closure permutation

3237:   Level: intermediate

3239:   Note:
3240:   The user must destroy the `IS` that is returned.

3242: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `IS`, `PetscSectionSetClosurePermutation()`, `PetscSectionGetClosureIndex()`, `PetscSectionSetClosureIndex()`, `DMPlexCreateClosureIndex()`
3243: @*/
3244: PetscErrorCode PetscSectionGetClosureInversePermutation(PetscSection section, PetscObject obj, PetscInt depth, PetscInt clSize, IS *perm)
3245: {
3246:   const PetscInt *clPerm = NULL;

3248:   PetscFunctionBegin;
3249:   PetscCall(PetscSectionGetClosureInversePermutation_Internal(section, obj, depth, clSize, &clPerm));
3250:   PetscCall(ISCreateGeneral(PETSC_COMM_SELF, clSize, clPerm, PETSC_USE_POINTER, perm));
3251:   PetscFunctionReturn(PETSC_SUCCESS);
3252: }

3254: /*@
3255:   PetscSectionGetField - Get the `PetscSection` associated with a single field

3257:   Input Parameters:
3258: + s     - The `PetscSection`
3259: - field - The field number

3261:   Output Parameter:
3262: . subs - The `PetscSection` for the given field, note the chart of `subs` is not set

3264:   Level: intermediate

3266:   Note:
3267:   Does not increase the reference count of the selected sub-section. There is no matching `PetscSectionRestoreField()`

3269: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `IS`, `PetscSectionSetNumFields()`
3270: @*/
3271: PetscErrorCode PetscSectionGetField(PetscSection s, PetscInt field, PetscSection *subs)
3272: {
3273:   PetscFunctionBegin;
3275:   PetscAssertPointer(subs, 3);
3276:   PetscSectionCheckValidField(field, s->numFields);
3277:   *subs = s->field[field];
3278:   PetscFunctionReturn(PETSC_SUCCESS);
3279: }

3281: PetscClassId      PETSC_SECTION_SYM_CLASSID;
3282: PetscFunctionList PetscSectionSymList = NULL;

3284: /*@
3285:   PetscSectionSymCreate - Creates an empty `PetscSectionSym` object.

3287:   Collective

3289:   Input Parameter:
3290: . comm - the MPI communicator

3292:   Output Parameter:
3293: . sym - pointer to the new set of symmetries

3295:   Level: developer

3297: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionSym`, `PetscSectionSymDestroy()`
3298: @*/
3299: PetscErrorCode PetscSectionSymCreate(MPI_Comm comm, PetscSectionSym *sym)
3300: {
3301:   PetscFunctionBegin;
3302:   PetscAssertPointer(sym, 2);
3303:   PetscCall(ISInitializePackage());

3305:   PetscCall(PetscHeaderCreate(*sym, PETSC_SECTION_SYM_CLASSID, "PetscSectionSym", "Section Symmetry", "IS", comm, PetscSectionSymDestroy, PetscSectionSymView));
3306:   PetscFunctionReturn(PETSC_SUCCESS);
3307: }

3309: /*@
3310:   PetscSectionSymSetType - Builds a `PetscSectionSym`, for a particular implementation.

3312:   Collective

3314:   Input Parameters:
3315: + sym    - The section symmetry object
3316: - method - The name of the section symmetry type

3318:   Level: developer

3320: .seealso: [PetscSection](sec_petscsection), `PetscSectionSym`, `PetscSectionSymType`, `PetscSectionSymGetType()`, `PetscSectionSymCreate()`
3321: @*/
3322: PetscErrorCode PetscSectionSymSetType(PetscSectionSym sym, PetscSectionSymType method)
3323: {
3324:   PetscErrorCode (*r)(PetscSectionSym);
3325:   PetscBool match;

3327:   PetscFunctionBegin;
3329:   PetscCall(PetscObjectTypeCompare((PetscObject)sym, method, &match));
3330:   if (match) PetscFunctionReturn(PETSC_SUCCESS);

3332:   PetscCall(PetscFunctionListFind(PetscSectionSymList, method, &r));
3333:   PetscCheck(r, PetscObjectComm((PetscObject)sym), PETSC_ERR_ARG_UNKNOWN_TYPE, "Unknown PetscSectionSym type: %s", method);
3334:   PetscTryTypeMethod(sym, destroy);
3335:   sym->ops->destroy = NULL;

3337:   PetscCall((*r)(sym));
3338:   PetscCall(PetscObjectChangeTypeName((PetscObject)sym, method));
3339:   PetscFunctionReturn(PETSC_SUCCESS);
3340: }

3342: /*@
3343:   PetscSectionSymGetType - Gets the section symmetry type name (as a string) from the `PetscSectionSym`.

3345:   Not Collective

3347:   Input Parameter:
3348: . sym - The section symmetry

3350:   Output Parameter:
3351: . type - The index set type name

3353:   Level: developer

3355: .seealso: [PetscSection](sec_petscsection), `PetscSectionSym`, `PetscSectionSymType`, `PetscSectionSymSetType()`, `PetscSectionSymCreate()`
3356: @*/
3357: PetscErrorCode PetscSectionSymGetType(PetscSectionSym sym, PetscSectionSymType *type)
3358: {
3359:   PetscFunctionBegin;
3361:   PetscAssertPointer(type, 2);
3362:   *type = ((PetscObject)sym)->type_name;
3363:   PetscFunctionReturn(PETSC_SUCCESS);
3364: }

3366: /*@C
3367:   PetscSectionSymRegister - Registers a new section symmetry implementation

3369:   Not Collective, No Fortran Support

3371:   Input Parameters:
3372: + sname    - The name of a new user-defined creation routine
3373: - function - The creation routine itself

3375:   Level: developer

3377:   Notes:
3378:   `PetscSectionSymRegister()` may be called multiple times to add several user-defined vectors

3380: .seealso: [PetscSection](sec_petscsection), `PetscSectionSym`, `PetscSectionSymType`, `PetscSectionSymCreate()`, `PetscSectionSymSetType()`
3381: @*/
3382: PetscErrorCode PetscSectionSymRegister(const char sname[], PetscErrorCode (*function)(PetscSectionSym))
3383: {
3384:   PetscFunctionBegin;
3385:   PetscCall(ISInitializePackage());
3386:   PetscCall(PetscFunctionListAdd(&PetscSectionSymList, sname, function));
3387:   PetscFunctionReturn(PETSC_SUCCESS);
3388: }

3390: /*@
3391:   PetscSectionSymDestroy - Destroys a section symmetry.

3393:   Collective

3395:   Input Parameter:
3396: . sym - the section symmetry

3398:   Level: developer

3400: .seealso: [PetscSection](sec_petscsection), `PetscSectionSym`, `PetscSectionSymCreate()`
3401: @*/
3402: PetscErrorCode PetscSectionSymDestroy(PetscSectionSym *sym)
3403: {
3404:   SymWorkLink link, next;

3406:   PetscFunctionBegin;
3407:   if (!*sym) PetscFunctionReturn(PETSC_SUCCESS);
3409:   if (--((PetscObject)*sym)->refct > 0) {
3410:     *sym = NULL;
3411:     PetscFunctionReturn(PETSC_SUCCESS);
3412:   }
3413:   PetscTryTypeMethod(*sym, destroy);
3414:   PetscCheck(!(*sym)->workout, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Work array still checked out");
3415:   for (link = (*sym)->workin; link; link = next) {
3416:     PetscInt    **perms = (PetscInt **)link->perms;
3417:     PetscScalar **rots  = (PetscScalar **)link->rots;
3418:     PetscCall(PetscFree2(perms, rots));
3419:     next = link->next;
3420:     PetscCall(PetscFree(link));
3421:   }
3422:   (*sym)->workin = NULL;
3423:   PetscCall(PetscHeaderDestroy(sym));
3424:   PetscFunctionReturn(PETSC_SUCCESS);
3425: }

3427: /*@
3428:   PetscSectionSymView - Displays a section symmetry

3430:   Collective

3432:   Input Parameters:
3433: + sym    - the index set
3434: - viewer - viewer used to display the set, for example `PETSC_VIEWER_STDOUT_SELF`.

3436:   Level: developer

3438: .seealso: `PetscSectionSym`, `PetscViewer`, `PetscViewerASCIIOpen()`
3439: @*/
3440: PetscErrorCode PetscSectionSymView(PetscSectionSym sym, PetscViewer viewer)
3441: {
3442:   PetscFunctionBegin;
3444:   if (!viewer) PetscCall(PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)sym), &viewer));
3446:   PetscCheckSameComm(sym, 1, viewer, 2);
3447:   PetscCall(PetscObjectPrintClassNamePrefixType((PetscObject)sym, viewer));
3448:   PetscTryTypeMethod(sym, view, viewer);
3449:   PetscFunctionReturn(PETSC_SUCCESS);
3450: }

3452: /*@
3453:   PetscSectionSetSym - Set the symmetries for the data referred to by the section

3455:   Collective

3457:   Input Parameters:
3458: + section - the section describing data layout
3459: - sym     - the symmetry describing the affect of orientation on the access of the data

3461:   Level: developer

3463: .seealso: [PetscSection](sec_petscsection), `PetscSectionSym`, `PetscSectionGetSym()`, `PetscSectionSymCreate()`
3464: @*/
3465: PetscErrorCode PetscSectionSetSym(PetscSection section, PetscSectionSym sym)
3466: {
3467:   PetscFunctionBegin;
3469:   PetscCall(PetscSectionSymDestroy(&section->sym));
3470:   if (sym) {
3472:     PetscCheckSameComm(section, 1, sym, 2);
3473:     PetscCall(PetscObjectReference((PetscObject)sym));
3474:   }
3475:   section->sym = sym;
3476:   PetscFunctionReturn(PETSC_SUCCESS);
3477: }

3479: /*@
3480:   PetscSectionGetSym - Get the symmetries for the data referred to by the section

3482:   Not Collective

3484:   Input Parameter:
3485: . section - the section describing data layout

3487:   Output Parameter:
3488: . sym - the symmetry describing the affect of orientation on the access of the data, provided previously by `PetscSectionSetSym()`

3490:   Level: developer

3492: .seealso: [PetscSection](sec_petscsection), `PetscSectionSym`, `PetscSectionSetSym()`, `PetscSectionSymCreate()`
3493: @*/
3494: PetscErrorCode PetscSectionGetSym(PetscSection section, PetscSectionSym *sym)
3495: {
3496:   PetscFunctionBegin;
3498:   *sym = section->sym;
3499:   PetscFunctionReturn(PETSC_SUCCESS);
3500: }

3502: /*@
3503:   PetscSectionSetFieldSym - Set the symmetries for the data referred to by a field of the section

3505:   Collective

3507:   Input Parameters:
3508: + section - the section describing data layout
3509: . field   - the field number
3510: - sym     - the symmetry describing the affect of orientation on the access of the data

3512:   Level: developer

3514: .seealso: [PetscSection](sec_petscsection), `PetscSectionSym`, `PetscSectionGetFieldSym()`, `PetscSectionSymCreate()`
3515: @*/
3516: PetscErrorCode PetscSectionSetFieldSym(PetscSection section, PetscInt field, PetscSectionSym sym)
3517: {
3518:   PetscFunctionBegin;
3520:   PetscSectionCheckValidField(field, section->numFields);
3521:   PetscCall(PetscSectionSetSym(section->field[field], sym));
3522:   PetscFunctionReturn(PETSC_SUCCESS);
3523: }

3525: /*@
3526:   PetscSectionGetFieldSym - Get the symmetries for the data referred to by a field of the section

3528:   Collective

3530:   Input Parameters:
3531: + section - the section describing data layout
3532: - field   - the field number

3534:   Output Parameter:
3535: . sym - the symmetry describing the affect of orientation on the access of the data

3537:   Level: developer

3539: .seealso: [PetscSection](sec_petscsection), `PetscSectionSym`, `PetscSectionSetFieldSym()`, `PetscSectionSymCreate()`
3540: @*/
3541: PetscErrorCode PetscSectionGetFieldSym(PetscSection section, PetscInt field, PetscSectionSym *sym)
3542: {
3543:   PetscFunctionBegin;
3545:   PetscSectionCheckValidField(field, section->numFields);
3546:   *sym = section->field[field]->sym;
3547:   PetscFunctionReturn(PETSC_SUCCESS);
3548: }

3550: /*@C
3551:   PetscSectionGetPointSyms - Get the symmetries for a set of points in a `PetscSection` under specific orientations.

3553:   Not Collective

3555:   Input Parameters:
3556: + section   - the section
3557: . numPoints - the number of points
3558: - points    - an array of size 2 * `numPoints`, containing a list of (point, orientation) pairs. (An orientation is an
3559:               arbitrary integer: its interpretation is up to sym.  Orientations are used by `DM`: for their interpretation in that
3560:               context, see `DMPlexGetConeOrientation()`).

3562:   Output Parameters:
3563: + perms - The permutations for the given orientations (or `NULL` if there is no symmetry or the permutation is the identity).
3564: - rots  - The field rotations symmetries for the given orientations (or `NULL` if there is no symmetry or the rotations are all
3565:     identity).

3567:   Example of usage, gathering dofs into a local array (lArray) from a section array (sArray):
3568: .vb
3569:      const PetscInt    **perms;
3570:      const PetscScalar **rots;
3571:      PetscInt            lOffset;

3573:      PetscSectionGetPointSyms(section,numPoints,points,&perms,&rots);
3574:      for (i = 0, lOffset = 0; i < numPoints; i++) {
3575:        PetscInt           point = points[2*i], dof, sOffset;
3576:        const PetscInt    *perm  = perms ? perms[i] : NULL;
3577:        const PetscScalar *rot   = rots  ? rots[i]  : NULL;

3579:        PetscSectionGetDof(section,point,&dof);
3580:        PetscSectionGetOffset(section,point,&sOffset);

3582:        if (perm) {for (j = 0; j < dof; j++) {lArray[lOffset + perm[j]]  = sArray[sOffset + j];}}
3583:        else      {for (j = 0; j < dof; j++) {lArray[lOffset +      j ]  = sArray[sOffset + j];}}
3584:        if (rot)  {for (j = 0; j < dof; j++) {lArray[lOffset +      j ] *= rot[j];             }}
3585:        lOffset += dof;
3586:      }
3587:      PetscSectionRestorePointSyms(section,numPoints,points,&perms,&rots);
3588: .ve

3590:   Example of usage, adding dofs into a section array (sArray) from a local array (lArray):
3591: .vb
3592:      const PetscInt    **perms;
3593:      const PetscScalar **rots;
3594:      PetscInt            lOffset;

3596:      PetscSectionGetPointSyms(section,numPoints,points,&perms,&rots);
3597:      for (i = 0, lOffset = 0; i < numPoints; i++) {
3598:        PetscInt           point = points[2*i], dof, sOffset;
3599:        const PetscInt    *perm  = perms ? perms[i] : NULL;
3600:        const PetscScalar *rot   = rots  ? rots[i]  : NULL;

3602:        PetscSectionGetDof(section,point,&dof);
3603:        PetscSectionGetOffset(section,point,&sOff);

3605:        if (perm) {for (j = 0; j < dof; j++) {sArray[sOffset + j] += lArray[lOffset + perm[j]] * (rot ? PetscConj(rot[perm[j]]) : 1.);}}
3606:        else      {for (j = 0; j < dof; j++) {sArray[sOffset + j] += lArray[lOffset +      j ] * (rot ? PetscConj(rot[     j ]) : 1.);}}
3607:        offset += dof;
3608:      }
3609:      PetscSectionRestorePointSyms(section,numPoints,points,&perms,&rots);
3610: .ve

3612:   Level: developer

3614:   Notes:
3615:   `PetscSectionSetSym()` must have been previously called to provide the symmetries to the `PetscSection`

3617:   Use `PetscSectionRestorePointSyms()` when finished with the data

3619: .seealso: [PetscSection](sec_petscsection), `PetscSectionSym`, `PetscSectionRestorePointSyms()`, `PetscSectionSymCreate()`, `PetscSectionSetSym()`, `PetscSectionGetSym()`
3620: @*/
3621: PetscErrorCode PetscSectionGetPointSyms(PetscSection section, PetscInt numPoints, const PetscInt *points, const PetscInt ***perms, const PetscScalar ***rots)
3622: {
3623:   PetscSectionSym sym;

3625:   PetscFunctionBegin;
3627:   if (numPoints) PetscAssertPointer(points, 3);
3628:   if (perms) *perms = NULL;
3629:   if (rots) *rots = NULL;
3630:   sym = section->sym;
3631:   if (sym && (perms || rots)) {
3632:     SymWorkLink link;

3634:     if (sym->workin) {
3635:       link        = sym->workin;
3636:       sym->workin = sym->workin->next;
3637:     } else {
3638:       PetscCall(PetscNew(&link));
3639:     }
3640:     if (numPoints > link->numPoints) {
3641:       PetscInt    **perms = (PetscInt **)link->perms;
3642:       PetscScalar **rots  = (PetscScalar **)link->rots;
3643:       PetscCall(PetscFree2(perms, rots));
3644:       PetscCall(PetscMalloc2(numPoints, (PetscInt ***)&link->perms, numPoints, (PetscScalar ***)&link->rots));
3645:       link->numPoints = numPoints;
3646:     }
3647:     link->next   = sym->workout;
3648:     sym->workout = link;
3649:     PetscCall(PetscArrayzero((PetscInt **)link->perms, numPoints));
3650:     PetscCall(PetscArrayzero((PetscInt **)link->rots, numPoints));
3651:     PetscUseTypeMethod(sym, getpoints, section, numPoints, points, link->perms, link->rots);
3652:     if (perms) *perms = link->perms;
3653:     if (rots) *rots = link->rots;
3654:   }
3655:   PetscFunctionReturn(PETSC_SUCCESS);
3656: }

3658: /*@C
3659:   PetscSectionRestorePointSyms - Restore the symmetries returned by `PetscSectionGetPointSyms()`

3661:   Not Collective

3663:   Input Parameters:
3664: + section   - the section
3665: . numPoints - the number of points
3666: . points    - an array of size 2 * `numPoints`, containing a list of (point, orientation) pairs. (An orientation is an
3667:               arbitrary integer: its interpretation is up to sym.  Orientations are used by `DM`: for their interpretation in that
3668:               context, see `DMPlexGetConeOrientation()`).
3669: . perms     - The permutations for the given orientations: set to `NULL` at conclusion
3670: - rots      - The field rotations symmetries for the given orientations: set to `NULL` at conclusion

3672:   Level: developer

3674: .seealso: [PetscSection](sec_petscsection), `PetscSectionSym`, `PetscSectionGetPointSyms()`, `PetscSectionSymCreate()`, `PetscSectionSetSym()`, `PetscSectionGetSym()`
3675: @*/
3676: PetscErrorCode PetscSectionRestorePointSyms(PetscSection section, PetscInt numPoints, const PetscInt *points, const PetscInt ***perms, const PetscScalar ***rots)
3677: {
3678:   PetscSectionSym sym;

3680:   PetscFunctionBegin;
3682:   sym = section->sym;
3683:   if (sym && (perms || rots)) {
3684:     SymWorkLink *p, link;

3686:     for (p = &sym->workout; (link = *p); p = &link->next) {
3687:       if ((perms && link->perms == *perms) || (rots && link->rots == *rots)) {
3688:         *p          = link->next;
3689:         link->next  = sym->workin;
3690:         sym->workin = link;
3691:         if (perms) *perms = NULL;
3692:         if (rots) *rots = NULL;
3693:         PetscFunctionReturn(PETSC_SUCCESS);
3694:       }
3695:     }
3696:     SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Array was not checked out");
3697:   }
3698:   PetscFunctionReturn(PETSC_SUCCESS);
3699: }

3701: /*@C
3702:   PetscSectionGetFieldPointSyms - Get the symmetries for a set of points in a field of a `PetscSection` under specific orientations.

3704:   Not Collective

3706:   Input Parameters:
3707: + section   - the section
3708: . field     - the field of the section
3709: . numPoints - the number of points
3710: - points    - an array of size 2 * `numPoints`, containing a list of (point, orientation) pairs. (An orientation is an
3711:     arbitrary integer: its interpretation is up to sym.  Orientations are used by `DM`: for their interpretation in that
3712:     context, see `DMPlexGetConeOrientation()`).

3714:   Output Parameters:
3715: + perms - The permutations for the given orientations (or `NULL` if there is no symmetry or the permutation is the identity).
3716: - rots  - The field rotations symmetries for the given orientations (or `NULL` if there is no symmetry or the rotations are all
3717:     identity).

3719:   Level: developer

3721:   Notes:
3722:   `PetscSectionSetFieldSym()` must have been previously called to provide the symmetries to the `PetscSection`

3724:   Use `PetscSectionRestoreFieldPointSyms()` when finished with the data

3726: .seealso: [PetscSection](sec_petscsection), `PetscSectionSym`, `PetscSectionGetPointSyms()`, `PetscSectionRestoreFieldPointSyms()`
3727: @*/
3728: PetscErrorCode PetscSectionGetFieldPointSyms(PetscSection section, PetscInt field, PetscInt numPoints, const PetscInt *points, const PetscInt ***perms, const PetscScalar ***rots)
3729: {
3730:   PetscFunctionBegin;
3732:   PetscCheck(field <= section->numFields, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "field %" PetscInt_FMT " greater than number of fields (%" PetscInt_FMT ") in section", field, section->numFields);
3733:   PetscCall(PetscSectionGetPointSyms(section->field[field], numPoints, points, perms, rots));
3734:   PetscFunctionReturn(PETSC_SUCCESS);
3735: }

3737: /*@C
3738:   PetscSectionRestoreFieldPointSyms - Restore the symmetries returned by `PetscSectionGetFieldPointSyms()`

3740:   Not Collective

3742:   Input Parameters:
3743: + section   - the section
3744: . field     - the field number
3745: . numPoints - the number of points
3746: . points    - an array of size 2 * `numPoints`, containing a list of (point, orientation) pairs. (An orientation is an
3747:     arbitrary integer: its interpretation is up to sym.  Orientations are used by `DM`: for their interpretation in that
3748:     context, see `DMPlexGetConeOrientation()`).
3749: . perms     - The permutations for the given orientations: set to NULL at conclusion
3750: - rots      - The field rotations symmetries for the given orientations: set to NULL at conclusion

3752:   Level: developer

3754: .seealso: [PetscSection](sec_petscsection), `PetscSectionSym`, `PetscSectionRestorePointSyms()`, `petscSectionGetFieldPointSyms()`, `PetscSectionSymCreate()`, `PetscSectionSetSym()`, `PetscSectionGetSym()`
3755: @*/
3756: PetscErrorCode PetscSectionRestoreFieldPointSyms(PetscSection section, PetscInt field, PetscInt numPoints, const PetscInt *points, const PetscInt ***perms, const PetscScalar ***rots)
3757: {
3758:   PetscFunctionBegin;
3760:   PetscCheck(field <= section->numFields, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "field %" PetscInt_FMT " greater than number of fields (%" PetscInt_FMT ") in section", field, section->numFields);
3761:   PetscCall(PetscSectionRestorePointSyms(section->field[field], numPoints, points, perms, rots));
3762:   PetscFunctionReturn(PETSC_SUCCESS);
3763: }

3765: /*@
3766:   PetscSectionSymCopy - Copy the symmetries, assuming that the point structure is compatible

3768:   Not Collective

3770:   Input Parameter:
3771: . sym - the `PetscSectionSym`

3773:   Output Parameter:
3774: . nsym - the equivalent symmetries

3776:   Level: developer

3778: .seealso: [PetscSection](sec_petscsection), `PetscSectionSym`, `PetscSectionSymCreate()`, `PetscSectionSetSym()`, `PetscSectionGetSym()`, `PetscSectionSymLabelSetStratum()`, `PetscSectionGetPointSyms()`
3779: @*/
3780: PetscErrorCode PetscSectionSymCopy(PetscSectionSym sym, PetscSectionSym nsym)
3781: {
3782:   PetscFunctionBegin;
3785:   PetscTryTypeMethod(sym, copy, nsym);
3786:   PetscFunctionReturn(PETSC_SUCCESS);
3787: }

3789: /*@
3790:   PetscSectionSymDistribute - Distribute the symmetries in accordance with the input `PetscSF`

3792:   Collective

3794:   Input Parameters:
3795: + sym         - the `PetscSectionSym`
3796: - migrationSF - the distribution map from roots to leaves

3798:   Output Parameter:
3799: . dsym - the redistributed symmetries

3801:   Level: developer

3803: .seealso: [PetscSection](sec_petscsection), `PetscSectionSym`, `PetscSectionSymCreate()`, `PetscSectionSetSym()`, `PetscSectionGetSym()`, `PetscSectionSymLabelSetStratum()`, `PetscSectionGetPointSyms()`
3804: @*/
3805: PetscErrorCode PetscSectionSymDistribute(PetscSectionSym sym, PetscSF migrationSF, PetscSectionSym *dsym)
3806: {
3807:   PetscFunctionBegin;
3810:   PetscAssertPointer(dsym, 3);
3811:   PetscTryTypeMethod(sym, distribute, migrationSF, dsym);
3812:   PetscFunctionReturn(PETSC_SUCCESS);
3813: }

3815: /*@
3816:   PetscSectionGetUseFieldOffsets - Get the flag indicating if field offsets are used directly in a global section, rather than just the point offset

3818:   Not Collective

3820:   Input Parameter:
3821: . s - the global `PetscSection`

3823:   Output Parameter:
3824: . flg - the flag

3826:   Level: developer

3828: .seealso: [PetscSection](sec_petscsection), `PetscSectionSym`, `PetscSectionSetChart()`, `PetscSectionCreate()`
3829: @*/
3830: PetscErrorCode PetscSectionGetUseFieldOffsets(PetscSection s, PetscBool *flg)
3831: {
3832:   PetscFunctionBegin;
3834:   *flg = s->useFieldOff;
3835:   PetscFunctionReturn(PETSC_SUCCESS);
3836: }

3838: /*@
3839:   PetscSectionSetUseFieldOffsets - Set the flag to use field offsets directly in a global section, rather than just the point offset

3841:   Not Collective

3843:   Input Parameters:
3844: + s   - the global `PetscSection`
3845: - flg - the flag

3847:   Level: developer

3849: .seealso: [PetscSection](sec_petscsection), `PetscSectionSym`, `PetscSectionGetUseFieldOffsets()`, `PetscSectionSetChart()`, `PetscSectionCreate()`
3850: @*/
3851: PetscErrorCode PetscSectionSetUseFieldOffsets(PetscSection s, PetscBool flg)
3852: {
3853:   PetscFunctionBegin;
3855:   s->useFieldOff = flg;
3856:   PetscFunctionReturn(PETSC_SUCCESS);
3857: }

3859: #define PetscSectionExpandPoints_Loop(TYPE) \
3860:   do { \
3861:     PetscInt i, n, o0, o1, size; \
3862:     TYPE    *a0 = (TYPE *)origArray, *a1; \
3863:     PetscCall(PetscSectionGetStorageSize(s, &size)); \
3864:     PetscCall(PetscMalloc1(size, &a1)); \
3865:     for (i = 0; i < npoints; i++) { \
3866:       PetscCall(PetscSectionGetOffset(origSection, points_[i], &o0)); \
3867:       PetscCall(PetscSectionGetOffset(s, i, &o1)); \
3868:       PetscCall(PetscSectionGetDof(s, i, &n)); \
3869:       PetscCall(PetscMemcpy(&a1[o1], &a0[o0], n *unitsize)); \
3870:     } \
3871:     *newArray = (void *)a1; \
3872:   } while (0)

3874: /*@
3875:   PetscSectionExtractDofsFromArray - Extracts elements of an array corresponding to DOFs of specified points.

3877:   Not Collective

3879:   Input Parameters:
3880: + origSection - the `PetscSection` describing the layout of the array
3881: . dataType    - `MPI_Datatype` describing the data type of the array (currently only `MPIU_INT`, `MPIU_SCALAR`, `MPIU_REAL`)
3882: . origArray   - the array; its size must be equal to the storage size of `origSection`
3883: - points      - `IS` with points to extract; its indices must lie in the chart of `origSection`

3885:   Output Parameters:
3886: + newSection - the new `PetscSection` describing the layout of the new array (with points renumbered 0,1,... but preserving numbers of DOFs)
3887: - newArray   - the array of the extracted DOFs; its size is the storage size of `newSection`

3889:   Level: developer

3891: .seealso: [PetscSection](sec_petscsection), `PetscSectionSym`, `PetscSectionGetChart()`, `PetscSectionGetDof()`, `PetscSectionGetStorageSize()`, `PetscSectionCreate()`
3892: @*/
3893: PetscErrorCode PetscSectionExtractDofsFromArray(PetscSection origSection, MPI_Datatype dataType, const void *origArray, IS points, PetscSection *newSection, void *newArray[])
3894: {
3895:   PetscSection    s;
3896:   const PetscInt *points_;
3897:   PetscInt        i, n, npoints, pStart, pEnd;
3898:   PetscMPIInt     unitsize;

3900:   PetscFunctionBegin;
3902:   PetscAssertPointer(origArray, 3);
3904:   if (newSection) PetscAssertPointer(newSection, 5);
3905:   if (newArray) PetscAssertPointer(newArray, 6);
3906:   PetscCallMPI(MPI_Type_size(dataType, &unitsize));
3907:   PetscCall(ISGetLocalSize(points, &npoints));
3908:   PetscCall(ISGetIndices(points, &points_));
3909:   PetscCall(PetscSectionGetChart(origSection, &pStart, &pEnd));
3910:   PetscCall(PetscSectionCreate(PETSC_COMM_SELF, &s));
3911:   PetscCall(PetscSectionSetChart(s, 0, npoints));
3912:   for (i = 0; i < npoints; i++) {
3913:     PetscCheck(points_[i] >= pStart && points_[i] < pEnd, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "point %" PetscInt_FMT " (index %" PetscInt_FMT ") in input IS out of input section's chart", points_[i], i);
3914:     PetscCall(PetscSectionGetDof(origSection, points_[i], &n));
3915:     PetscCall(PetscSectionSetDof(s, i, n));
3916:   }
3917:   PetscCall(PetscSectionSetUp(s));
3918:   if (newArray) {
3919:     if (dataType == MPIU_INT) {
3920:       PetscSectionExpandPoints_Loop(PetscInt);
3921:     } else if (dataType == MPIU_SCALAR) {
3922:       PetscSectionExpandPoints_Loop(PetscScalar);
3923:     } else if (dataType == MPIU_REAL) {
3924:       PetscSectionExpandPoints_Loop(PetscReal);
3925:     } else SETERRQ(PETSC_COMM_SELF, PETSC_ERR_SUP, "not implemented for this MPI_Datatype");
3926:   }
3927:   if (newSection) {
3928:     *newSection = s;
3929:   } else {
3930:     PetscCall(PetscSectionDestroy(&s));
3931:   }
3932:   PetscCall(ISRestoreIndices(points, &points_));
3933:   PetscFunctionReturn(PETSC_SUCCESS);
3934: }