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, &s->fieldNames[f]));
399:     PetscCall(PetscSNPrintf(name, 64, "Component_0"));
400:     PetscCall(PetscMalloc1(s->numFieldComponents[f], &s->compNames[f]));
401:     PetscCall(PetscStrallocpy(name, &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, &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, &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, &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, &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:   PetscInt        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, foff));
1570:       PetscCall(PetscSectionGetFieldConstraintDof(gs, p, f, &cdof));
1571:       foff = off < 0 ? foff - (dof - cdof) : foff + (dof - cdof);
1572:     }
1573:   }
1574:   for (f = 0; f < numFields; ++f) {
1575:     PetscSection gfs = gs->field[f];

1577:     PetscCall(PetscSectionSetUpBC(gfs));
1578:     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]));
1579:   }
1580:   gs->setup = PETSC_TRUE;
1581:   PetscCall(PetscSectionViewFromOptions(gs, NULL, "-global_section_view"));
1582:   *gsection = gs;
1583:   PetscFunctionReturn(PETSC_SUCCESS);
1584: }

1586: /*@
1587:   PetscSectionCreateGlobalSectionCensored - Create a `PetscSection` describing the globallayout using
1588:   a local (sequential) `PetscSection` on each MPI process and an `PetscSF` describing the section point overlap.

1590:   Input Parameters:
1591: + s                  - The `PetscSection` for the local field layout
1592: . sf                 - The `PetscSF` describing parallel layout of the section points
1593: . includeConstraints - By default this is `PETSC_FALSE`, meaning that the global vector will not possess constrained dofs
1594: . numExcludes        - The number of exclusion ranges, this must have the same value on all MPI processes
1595: - 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

1597:   Output Parameter:
1598: . gsection - The `PetscSection` for the global field layout

1600:   Level: advanced

1602:   Notes:
1603:   On each MPI process `gsection` inherits the chart of the `s` on that process.

1605:   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`.
1606:   In those locations the value of size is -(size+1) and the value of the offset on the remote process is -(off+1).

1608:   This routine augments `PetscSectionCreateGlobalSection()` by allowing one to exclude certain ranges in the chart of the `PetscSection`

1610:   Developer Notes:
1611:   This is a terrible function name

1613: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionCreate()`
1614: @*/
1615: PetscErrorCode PetscSectionCreateGlobalSectionCensored(PetscSection s, PetscSF sf, PetscBool includeConstraints, PetscInt numExcludes, const PetscInt excludes[], PetscSection *gsection)
1616: {
1617:   const PetscInt *pind = NULL;
1618:   PetscInt       *neg = NULL, *tmpOff = NULL;
1619:   PetscInt        pStart, pEnd, p, e, dof, cdof, globalOff = 0, nroots;
1620:   PetscInt        off;

1622:   PetscFunctionBegin;
1625:   PetscAssertPointer(gsection, 6);
1626:   PetscCall(PetscSectionCreate(PetscObjectComm((PetscObject)s), gsection));
1627:   PetscCall(PetscSectionGetChart(s, &pStart, &pEnd));
1628:   PetscCall(PetscSectionSetChart(*gsection, pStart, pEnd));
1629:   PetscCall(PetscSFGetGraph(sf, &nroots, NULL, NULL, NULL));
1630:   if (nroots >= 0) {
1631:     PetscCheck(nroots >= pEnd - pStart, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "PetscSF nroots %" PetscInt_FMT " < %" PetscInt_FMT " section size", nroots, pEnd - pStart);
1632:     PetscCall(PetscCalloc1(nroots, &neg));
1633:     if (nroots > pEnd - pStart) {
1634:       PetscCall(PetscCalloc1(nroots, &tmpOff));
1635:     } else {
1636:       tmpOff = &(*gsection)->atlasDof[-pStart];
1637:     }
1638:   }
1639:   /* Mark ghost points with negative dof */
1640:   for (p = pStart; p < pEnd; ++p) {
1641:     for (e = 0; e < numExcludes; ++e) {
1642:       if ((p >= excludes[e * 2 + 0]) && (p < excludes[e * 2 + 1])) {
1643:         PetscCall(PetscSectionSetDof(*gsection, p, 0));
1644:         break;
1645:       }
1646:     }
1647:     if (e < numExcludes) continue;
1648:     PetscCall(PetscSectionGetDof(s, p, &dof));
1649:     PetscCall(PetscSectionSetDof(*gsection, p, dof));
1650:     PetscCall(PetscSectionGetConstraintDof(s, p, &cdof));
1651:     if (!includeConstraints && cdof > 0) PetscCall(PetscSectionSetConstraintDof(*gsection, p, cdof));
1652:     if (neg) neg[p] = -(dof + 1);
1653:   }
1654:   PetscCall(PetscSectionSetUpBC(*gsection));
1655:   if (nroots >= 0) {
1656:     PetscCall(PetscSFBcastBegin(sf, MPIU_INT, neg, tmpOff, MPI_REPLACE));
1657:     PetscCall(PetscSFBcastEnd(sf, MPIU_INT, neg, tmpOff, MPI_REPLACE));
1658:     if (nroots > pEnd - pStart) {
1659:       for (p = pStart; p < pEnd; ++p) {
1660:         if (tmpOff[p] < 0) (*gsection)->atlasDof[p - pStart] = tmpOff[p];
1661:       }
1662:     }
1663:   }
1664:   /* Calculate new sizes, get process offset, and calculate point offsets */
1665:   if (s->perm) PetscCall(ISGetIndices(s->perm, &pind));
1666:   for (p = 0, off = 0; p < pEnd - pStart; ++p) {
1667:     const PetscInt q = pind ? pind[p] : p;

1669:     cdof                     = (!includeConstraints && s->bc) ? s->bc->atlasDof[q] : 0;
1670:     (*gsection)->atlasOff[q] = off;
1671:     off += (*gsection)->atlasDof[q] > 0 ? (*gsection)->atlasDof[q] - cdof : 0;
1672:   }
1673:   PetscCallMPI(MPI_Scan(&off, &globalOff, 1, MPIU_INT, MPI_SUM, PetscObjectComm((PetscObject)s)));
1674:   globalOff -= off;
1675:   for (p = 0, off = 0; p < pEnd - pStart; ++p) {
1676:     (*gsection)->atlasOff[p] += globalOff;
1677:     if (neg) neg[p + pStart] = -((*gsection)->atlasOff[p] + 1);
1678:   }
1679:   if (s->perm) PetscCall(ISRestoreIndices(s->perm, &pind));
1680:   /* Put in negative offsets for ghost points */
1681:   if (nroots >= 0) {
1682:     if (nroots == pEnd - pStart) tmpOff = &(*gsection)->atlasOff[-pStart];
1683:     PetscCall(PetscSFBcastBegin(sf, MPIU_INT, neg, tmpOff, MPI_REPLACE));
1684:     PetscCall(PetscSFBcastEnd(sf, MPIU_INT, neg, tmpOff, MPI_REPLACE));
1685:     if (nroots > pEnd - pStart) {
1686:       for (p = pStart; p < pEnd; ++p) {
1687:         if (tmpOff[p] < 0) (*gsection)->atlasOff[p - pStart] = tmpOff[p];
1688:       }
1689:     }
1690:   }
1691:   if (nroots >= 0 && nroots > pEnd - pStart) PetscCall(PetscFree(tmpOff));
1692:   PetscCall(PetscFree(neg));
1693:   PetscFunctionReturn(PETSC_SUCCESS);
1694: }

1696: /*@
1697:   PetscSectionGetPointLayout - Get a `PetscLayout` for the points with nonzero dof counts of the unnamed default field within this `PetscSection`s local chart

1699:   Collective

1701:   Input Parameters:
1702: + comm - The `MPI_Comm`
1703: - s    - The `PetscSection`

1705:   Output Parameter:
1706: . layout - The point layout for the data that defines the section

1708:   Level: advanced

1710:   Notes:
1711:   `PetscSectionGetValueLayout()` provides similar information but counting the total number of degrees of freedom on the MPI process (excluding constrained
1712:   degrees of freedom).

1714:   This count includes constrained degrees of freedom

1716:   This is usually called on the default global section.

1718:   Example:
1719: .vb
1720:      The chart is [2,5), point 2 has 2 dof, point 3 has 0 dof, point 4 has 1 dof
1721:      The local size of the `PetscLayout` is 2 since 2 points have a non-zero number of dof
1722: .ve

1724:   Developer Notes:
1725:   I find the names of these two functions extremely non-informative

1727: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionGetValueLayout()`, `PetscSectionCreate()`
1728: @*/
1729: PetscErrorCode PetscSectionGetPointLayout(MPI_Comm comm, PetscSection s, PetscLayout *layout)
1730: {
1731:   PetscInt pStart, pEnd, p, localSize = 0;

1733:   PetscFunctionBegin;
1734:   PetscCall(PetscSectionGetChart(s, &pStart, &pEnd));
1735:   for (p = pStart; p < pEnd; ++p) {
1736:     PetscInt dof;

1738:     PetscCall(PetscSectionGetDof(s, p, &dof));
1739:     if (dof >= 0) ++localSize;
1740:   }
1741:   PetscCall(PetscLayoutCreate(comm, layout));
1742:   PetscCall(PetscLayoutSetLocalSize(*layout, localSize));
1743:   PetscCall(PetscLayoutSetBlockSize(*layout, 1));
1744:   PetscCall(PetscLayoutSetUp(*layout));
1745:   PetscFunctionReturn(PETSC_SUCCESS);
1746: }

1748: /*@
1749:   PetscSectionGetValueLayout - Get the `PetscLayout` associated with the section dofs of a `PetscSection`

1751:   Collective

1753:   Input Parameters:
1754: + comm - The `MPI_Comm`
1755: - s    - The `PetscSection`

1757:   Output Parameter:
1758: . layout - The dof layout for the section

1760:   Level: advanced

1762:   Notes:
1763:   `PetscSectionGetPointLayout()` provides similar information but only counting the number of points with nonzero degrees of freedom and
1764:   including the constrained degrees of freedom

1766:   This is usually called for the default global section.

1768:   Example:
1769: .vb
1770:      The chart is [2,5), point 2 has 4 dof (2 constrained), point 3 has 0 dof, point 4 has 1 dof (not constrained)
1771:      The local size of the `PetscLayout` is 3 since there are 3 unconstrained degrees of freedom on this MPI process
1772: .ve

1774: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionGetPointLayout()`, `PetscSectionCreate()`
1775: @*/
1776: PetscErrorCode PetscSectionGetValueLayout(MPI_Comm comm, PetscSection s, PetscLayout *layout)
1777: {
1778:   PetscInt pStart, pEnd, p, localSize = 0;

1780:   PetscFunctionBegin;
1782:   PetscAssertPointer(layout, 3);
1783:   PetscCall(PetscSectionGetChart(s, &pStart, &pEnd));
1784:   for (p = pStart; p < pEnd; ++p) {
1785:     PetscInt dof, cdof;

1787:     PetscCall(PetscSectionGetDof(s, p, &dof));
1788:     PetscCall(PetscSectionGetConstraintDof(s, p, &cdof));
1789:     if (dof - cdof > 0) localSize += dof - cdof;
1790:   }
1791:   PetscCall(PetscLayoutCreate(comm, layout));
1792:   PetscCall(PetscLayoutSetLocalSize(*layout, localSize));
1793:   PetscCall(PetscLayoutSetBlockSize(*layout, 1));
1794:   PetscCall(PetscLayoutSetUp(*layout));
1795:   PetscFunctionReturn(PETSC_SUCCESS);
1796: }

1798: /*@
1799:   PetscSectionGetOffset - Return the offset into an array or `Vec` for the dof associated with the given point.

1801:   Not Collective

1803:   Input Parameters:
1804: + s     - the `PetscSection`
1805: - point - the point

1807:   Output Parameter:
1808: . offset - the offset

1810:   Level: intermediate

1812:   Notes:
1813:   In a global section, `offset` will be negative for points not owned by this process.

1815:   This is for the unnamed default field in the `PetscSection` not the named fields

1817:   The `offset` values are different depending on a value set with `PetscSectionSetPointMajor()`

1819: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionGetFieldOffset()`, `PetscSectionCreate()`, `PetscSectionSetPointMajor()`
1820: @*/
1821: PetscErrorCode PetscSectionGetOffset(PetscSection s, PetscInt point, PetscInt *offset)
1822: {
1823:   PetscFunctionBegin;
1825:   PetscAssertPointer(offset, 3);
1826:   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);
1827:   *offset = s->atlasOff[point - s->pStart];
1828:   PetscFunctionReturn(PETSC_SUCCESS);
1829: }

1831: /*@
1832:   PetscSectionSetOffset - Set the offset into an array or `Vec` for the dof associated with the given point.

1834:   Not Collective

1836:   Input Parameters:
1837: + s      - the `PetscSection`
1838: . point  - the point
1839: - offset - the offset, these values may be negative indicating the values are off process

1841:   Level: developer

1843:   Note:
1844:   The user usually does not call this function, but uses `PetscSectionSetUp()`

1846: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionGetFieldOffset()`, `PetscSectionCreate()`, `PetscSectionSetUp()`
1847: @*/
1848: PetscErrorCode PetscSectionSetOffset(PetscSection s, PetscInt point, PetscInt offset)
1849: {
1850:   PetscFunctionBegin;
1852:   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);
1853:   s->atlasOff[point - s->pStart] = offset;
1854:   PetscFunctionReturn(PETSC_SUCCESS);
1855: }

1857: /*@
1858:   PetscSectionGetFieldOffset - Return the offset into an array or `Vec` for the field dof associated with the given point.

1860:   Not Collective

1862:   Input Parameters:
1863: + s     - the `PetscSection`
1864: . point - the point
1865: - field - the field

1867:   Output Parameter:
1868: . offset - the offset

1870:   Level: intermediate

1872:   Notes:
1873:   In a global section, `offset` will be negative for points not owned by this process.

1875:   The `offset` values are different depending on a value set with `PetscSectionSetPointMajor()`

1877: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionGetOffset()`, `PetscSectionCreate()`, `PetscSectionGetFieldPointOffset()`
1878: @*/
1879: PetscErrorCode PetscSectionGetFieldOffset(PetscSection s, PetscInt point, PetscInt field, PetscInt *offset)
1880: {
1881:   PetscFunctionBegin;
1883:   PetscAssertPointer(offset, 4);
1884:   PetscSectionCheckValidField(field, s->numFields);
1885:   PetscCall(PetscSectionGetOffset(s->field[field], point, offset));
1886:   PetscFunctionReturn(PETSC_SUCCESS);
1887: }

1889: /*@
1890:   PetscSectionSetFieldOffset - Set the offset into an array or `Vec` for the dof associated with the given field at a point.

1892:   Not Collective

1894:   Input Parameters:
1895: + s      - the `PetscSection`
1896: . point  - the point
1897: . field  - the field
1898: - offset - the offset, these values may be negative indicating the values are off process

1900:   Level: developer

1902:   Note:
1903:   The user usually does not call this function, but uses `PetscSectionSetUp()`

1905: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionGetFieldOffset()`, `PetscSectionSetOffset()`, `PetscSectionCreate()`, `PetscSectionSetUp()`
1906: @*/
1907: PetscErrorCode PetscSectionSetFieldOffset(PetscSection s, PetscInt point, PetscInt field, PetscInt offset)
1908: {
1909:   PetscFunctionBegin;
1911:   PetscSectionCheckValidField(field, s->numFields);
1912:   PetscCall(PetscSectionSetOffset(s->field[field], point, offset));
1913:   PetscFunctionReturn(PETSC_SUCCESS);
1914: }

1916: /*@
1917:   PetscSectionGetFieldPointOffset - Return the offset for the first field dof associated with the given point relative to the offset for that point for the
1918:   unnamed default field's first dof

1920:   Not Collective

1922:   Input Parameters:
1923: + s     - the `PetscSection`
1924: . point - the point
1925: - field - the field

1927:   Output Parameter:
1928: . offset - the offset

1930:   Level: advanced

1932:   Note:
1933:   This ignores constraints

1935:   Example:
1936: .vb
1937:   if PetscSectionSetPointMajor(s,PETSC_TRUE)
1938:   The unnamed default field has 3 dof at `point`
1939:   Field 0 has 2 dof at `point`
1940:   Then PetscSectionGetFieldPointOffset(s,point,1,&offset) returns and offset of 5
1941: .ve

1943: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionGetOffset()`, `PetscSectionCreate()`, `PetscSectionGetFieldOffset()`
1944: @*/
1945: PetscErrorCode PetscSectionGetFieldPointOffset(PetscSection s, PetscInt point, PetscInt field, PetscInt *offset)
1946: {
1947:   PetscInt off, foff;

1949:   PetscFunctionBegin;
1951:   PetscAssertPointer(offset, 4);
1952:   PetscSectionCheckValidField(field, s->numFields);
1953:   PetscCall(PetscSectionGetOffset(s, point, &off));
1954:   PetscCall(PetscSectionGetOffset(s->field[field], point, &foff));
1955:   *offset = foff - off;
1956:   PetscFunctionReturn(PETSC_SUCCESS);
1957: }

1959: /*@
1960:   PetscSectionGetOffsetRange - Return the full range of offsets [`start`, `end`) for a `PetscSection`

1962:   Not Collective

1964:   Input Parameter:
1965: . s - the `PetscSection`

1967:   Output Parameters:
1968: + start - the minimum offset
1969: - end   - one more than the maximum offset

1971:   Level: intermediate

1973: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionGetOffset()`, `PetscSectionCreate()`
1974: @*/
1975: PetscErrorCode PetscSectionGetOffsetRange(PetscSection s, PetscInt *start, PetscInt *end)
1976: {
1977:   PetscInt os = 0, oe = 0, pStart, pEnd, p;

1979:   PetscFunctionBegin;
1981:   if (s->atlasOff) {
1982:     os = s->atlasOff[0];
1983:     oe = s->atlasOff[0];
1984:   }
1985:   PetscCall(PetscSectionGetChart(s, &pStart, &pEnd));
1986:   for (p = 0; p < pEnd - pStart; ++p) {
1987:     PetscInt dof = s->atlasDof[p], off = s->atlasOff[p];

1989:     if (off >= 0) {
1990:       os = PetscMin(os, off);
1991:       oe = PetscMax(oe, off + dof);
1992:     }
1993:   }
1994:   if (start) *start = os;
1995:   if (end) *end = oe;
1996:   PetscFunctionReturn(PETSC_SUCCESS);
1997: }

1999: /*@
2000:   PetscSectionCreateSubsection - Create a new, smaller `PetscSection` composed of only selected fields

2002:   Collective

2004:   Input Parameters:
2005: + s      - the `PetscSection`
2006: . len    - the number of subfields
2007: - fields - the subfield numbers

2009:   Output Parameter:
2010: . subs - the subsection

2012:   Level: advanced

2014:   Notes:
2015:   The chart of `subs` is the same as the chart of `s`

2017:   This will error if a fieldnumber is out of range

2019: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionCreateSupersection()`, `PetscSectionCreate()`
2020: @*/
2021: PetscErrorCode PetscSectionCreateSubsection(PetscSection s, PetscInt len, const PetscInt fields[], PetscSection *subs)
2022: {
2023:   PetscInt nF, f, c, pStart, pEnd, p, maxCdof = 0;

2025:   PetscFunctionBegin;
2026:   if (!len) PetscFunctionReturn(PETSC_SUCCESS);
2028:   PetscAssertPointer(fields, 3);
2029:   PetscAssertPointer(subs, 4);
2030:   PetscCall(PetscSectionGetNumFields(s, &nF));
2031:   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);
2032:   PetscCall(PetscSectionCreate(PetscObjectComm((PetscObject)s), subs));
2033:   PetscCall(PetscSectionSetNumFields(*subs, len));
2034:   for (f = 0; f < len; ++f) {
2035:     const char     *name    = NULL;
2036:     PetscInt        numComp = 0;
2037:     PetscSectionSym sym;

2039:     PetscCall(PetscSectionGetFieldName(s, fields[f], &name));
2040:     PetscCall(PetscSectionSetFieldName(*subs, f, name));
2041:     PetscCall(PetscSectionGetFieldComponents(s, fields[f], &numComp));
2042:     PetscCall(PetscSectionSetFieldComponents(*subs, f, numComp));
2043:     for (c = 0; c < s->numFieldComponents[fields[f]]; ++c) {
2044:       PetscCall(PetscSectionGetComponentName(s, fields[f], c, &name));
2045:       PetscCall(PetscSectionSetComponentName(*subs, f, c, name));
2046:     }
2047:     PetscCall(PetscSectionGetFieldSym(s, fields[f], &sym));
2048:     PetscCall(PetscSectionSetFieldSym(*subs, f, sym));
2049:   }
2050:   PetscCall(PetscSectionGetChart(s, &pStart, &pEnd));
2051:   PetscCall(PetscSectionSetChart(*subs, pStart, pEnd));
2052:   for (p = pStart; p < pEnd; ++p) {
2053:     PetscInt dof = 0, cdof = 0, fdof = 0, cfdof = 0;

2055:     for (f = 0; f < len; ++f) {
2056:       PetscCall(PetscSectionGetFieldDof(s, p, fields[f], &fdof));
2057:       PetscCall(PetscSectionSetFieldDof(*subs, p, f, fdof));
2058:       PetscCall(PetscSectionGetFieldConstraintDof(s, p, fields[f], &cfdof));
2059:       if (cfdof) PetscCall(PetscSectionSetFieldConstraintDof(*subs, p, f, cfdof));
2060:       dof += fdof;
2061:       cdof += cfdof;
2062:     }
2063:     PetscCall(PetscSectionSetDof(*subs, p, dof));
2064:     if (cdof) PetscCall(PetscSectionSetConstraintDof(*subs, p, cdof));
2065:     maxCdof = PetscMax(cdof, maxCdof);
2066:   }
2067:   PetscCall(PetscSectionSetUp(*subs));
2068:   if (maxCdof) {
2069:     PetscInt *indices;

2071:     PetscCall(PetscMalloc1(maxCdof, &indices));
2072:     for (p = pStart; p < pEnd; ++p) {
2073:       PetscInt cdof;

2075:       PetscCall(PetscSectionGetConstraintDof(*subs, p, &cdof));
2076:       if (cdof) {
2077:         const PetscInt *oldIndices = NULL;
2078:         PetscInt        fdof = 0, cfdof = 0, fc, numConst = 0, fOff = 0;

2080:         for (f = 0; f < len; ++f) {
2081:           PetscCall(PetscSectionGetFieldDof(s, p, fields[f], &fdof));
2082:           PetscCall(PetscSectionGetFieldConstraintDof(s, p, fields[f], &cfdof));
2083:           PetscCall(PetscSectionGetFieldConstraintIndices(s, p, fields[f], &oldIndices));
2084:           PetscCall(PetscSectionSetFieldConstraintIndices(*subs, p, f, oldIndices));
2085:           for (fc = 0; fc < cfdof; ++fc) indices[numConst + fc] = oldIndices[fc] + fOff;
2086:           numConst += cfdof;
2087:           fOff += fdof;
2088:         }
2089:         PetscCall(PetscSectionSetConstraintIndices(*subs, p, indices));
2090:       }
2091:     }
2092:     PetscCall(PetscFree(indices));
2093:   }
2094:   PetscFunctionReturn(PETSC_SUCCESS);
2095: }

2097: /*@
2098:   PetscSectionCreateComponentSubsection - Create a new, smaller `PetscSection` composed of only selected components

2100:   Collective

2102:   Input Parameters:
2103: + s     - the `PetscSection`
2104: . len   - the number of components
2105: - comps - the component numbers

2107:   Output Parameter:
2108: . subs - the subsection

2110:   Level: advanced

2112:   Notes:
2113:   The chart of `subs` is the same as the chart of `s`

2115:   This will error if the section has more than one field, or if a component number is out of range

2117: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionCreateSupersection()`, `PetscSectionCreate()`
2118: @*/
2119: PetscErrorCode PetscSectionCreateComponentSubsection(PetscSection s, PetscInt len, const PetscInt comps[], PetscSection *subs)
2120: {
2121:   PetscSectionSym sym;
2122:   const char     *name = NULL;
2123:   PetscInt        Nf, pStart, pEnd;

2125:   PetscFunctionBegin;
2126:   if (!len) PetscFunctionReturn(PETSC_SUCCESS);
2128:   PetscAssertPointer(comps, 3);
2129:   PetscAssertPointer(subs, 4);
2130:   PetscCall(PetscSectionGetNumFields(s, &Nf));
2131:   PetscCheck(Nf == 1, PetscObjectComm((PetscObject)s), PETSC_ERR_ARG_WRONG, "This method can only handle one field, not %" PetscInt_FMT, Nf);
2132:   PetscCall(PetscSectionCreate(PetscObjectComm((PetscObject)s), subs));
2133:   PetscCall(PetscSectionSetNumFields(*subs, 1));
2134:   PetscCall(PetscSectionGetFieldName(s, 0, &name));
2135:   PetscCall(PetscSectionSetFieldName(*subs, 0, name));
2136:   PetscCall(PetscSectionSetFieldComponents(*subs, 0, len));
2137:   PetscCall(PetscSectionGetFieldSym(s, 0, &sym));
2138:   PetscCall(PetscSectionSetFieldSym(*subs, 0, sym));
2139:   for (PetscInt c = 0; c < len; ++c) {
2140:     PetscCall(PetscSectionGetComponentName(s, 0, comps[c], &name));
2141:     PetscCall(PetscSectionSetComponentName(*subs, 0, c, name));
2142:   }
2143:   PetscCall(PetscSectionGetChart(s, &pStart, &pEnd));
2144:   PetscCall(PetscSectionSetChart(*subs, pStart, pEnd));
2145:   for (PetscInt p = pStart; p < pEnd; ++p) {
2146:     PetscInt dof, cdof, cfdof;

2148:     PetscCall(PetscSectionGetDof(s, p, &dof));
2149:     if (!dof) continue;
2150:     PetscCall(PetscSectionGetFieldConstraintDof(s, p, 0, &cfdof));
2151:     PetscCall(PetscSectionGetConstraintDof(s, p, &cdof));
2152:     PetscCheck(!cdof && !cfdof, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Component selection does not work with constraints");
2153:     PetscCall(PetscSectionSetFieldDof(*subs, p, 0, len));
2154:     PetscCall(PetscSectionSetDof(*subs, p, len));
2155:   }
2156:   PetscCall(PetscSectionSetUp(*subs));
2157:   PetscFunctionReturn(PETSC_SUCCESS);
2158: }

2160: /*@
2161:   PetscSectionCreateSupersection - Create a new, larger section composed of multiple `PetscSection`s

2163:   Collective

2165:   Input Parameters:
2166: + s   - the input sections
2167: - len - the number of input sections

2169:   Output Parameter:
2170: . supers - the supersection

2172:   Level: advanced

2174:   Notes:
2175:   The section offsets now refer to a new, larger vector.

2177:   Developer Notes:
2178:   Needs to explain how the sections are composed

2180: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionCreateSubsection()`, `PetscSectionCreate()`
2181: @*/
2182: PetscErrorCode PetscSectionCreateSupersection(PetscSection s[], PetscInt len, PetscSection *supers)
2183: {
2184:   PetscInt Nf = 0, f, pStart = PETSC_INT_MAX, pEnd = 0, p, maxCdof = 0, i;

2186:   PetscFunctionBegin;
2187:   if (!len) PetscFunctionReturn(PETSC_SUCCESS);
2188:   for (i = 0; i < len; ++i) {
2189:     PetscInt nf, pStarti, pEndi;

2191:     PetscCall(PetscSectionGetNumFields(s[i], &nf));
2192:     PetscCall(PetscSectionGetChart(s[i], &pStarti, &pEndi));
2193:     pStart = PetscMin(pStart, pStarti);
2194:     pEnd   = PetscMax(pEnd, pEndi);
2195:     Nf += nf;
2196:   }
2197:   PetscCall(PetscSectionCreate(PetscObjectComm((PetscObject)s[0]), supers));
2198:   PetscCall(PetscSectionSetNumFields(*supers, Nf));
2199:   for (i = 0, f = 0; i < len; ++i) {
2200:     PetscInt nf, fi, ci;

2202:     PetscCall(PetscSectionGetNumFields(s[i], &nf));
2203:     for (fi = 0; fi < nf; ++fi, ++f) {
2204:       const char *name    = NULL;
2205:       PetscInt    numComp = 0;

2207:       PetscCall(PetscSectionGetFieldName(s[i], fi, &name));
2208:       PetscCall(PetscSectionSetFieldName(*supers, f, name));
2209:       PetscCall(PetscSectionGetFieldComponents(s[i], fi, &numComp));
2210:       PetscCall(PetscSectionSetFieldComponents(*supers, f, numComp));
2211:       for (ci = 0; ci < s[i]->numFieldComponents[fi]; ++ci) {
2212:         PetscCall(PetscSectionGetComponentName(s[i], fi, ci, &name));
2213:         PetscCall(PetscSectionSetComponentName(*supers, f, ci, name));
2214:       }
2215:     }
2216:   }
2217:   PetscCall(PetscSectionSetChart(*supers, pStart, pEnd));
2218:   for (p = pStart; p < pEnd; ++p) {
2219:     PetscInt dof = 0, cdof = 0;

2221:     for (i = 0, f = 0; i < len; ++i) {
2222:       PetscInt nf, fi, pStarti, pEndi;
2223:       PetscInt fdof = 0, cfdof = 0;

2225:       PetscCall(PetscSectionGetNumFields(s[i], &nf));
2226:       PetscCall(PetscSectionGetChart(s[i], &pStarti, &pEndi));
2227:       if ((p < pStarti) || (p >= pEndi)) continue;
2228:       for (fi = 0; fi < nf; ++fi, ++f) {
2229:         PetscCall(PetscSectionGetFieldDof(s[i], p, fi, &fdof));
2230:         PetscCall(PetscSectionAddFieldDof(*supers, p, f, fdof));
2231:         PetscCall(PetscSectionGetFieldConstraintDof(s[i], p, fi, &cfdof));
2232:         if (cfdof) PetscCall(PetscSectionAddFieldConstraintDof(*supers, p, f, cfdof));
2233:         dof += fdof;
2234:         cdof += cfdof;
2235:       }
2236:     }
2237:     PetscCall(PetscSectionSetDof(*supers, p, dof));
2238:     if (cdof) PetscCall(PetscSectionSetConstraintDof(*supers, p, cdof));
2239:     maxCdof = PetscMax(cdof, maxCdof);
2240:   }
2241:   PetscCall(PetscSectionSetUp(*supers));
2242:   if (maxCdof) {
2243:     PetscInt *indices;

2245:     PetscCall(PetscMalloc1(maxCdof, &indices));
2246:     for (p = pStart; p < pEnd; ++p) {
2247:       PetscInt cdof;

2249:       PetscCall(PetscSectionGetConstraintDof(*supers, p, &cdof));
2250:       if (cdof) {
2251:         PetscInt dof, numConst = 0, fOff = 0;

2253:         for (i = 0, f = 0; i < len; ++i) {
2254:           const PetscInt *oldIndices = NULL;
2255:           PetscInt        nf, fi, pStarti, pEndi, fdof, cfdof, fc;

2257:           PetscCall(PetscSectionGetNumFields(s[i], &nf));
2258:           PetscCall(PetscSectionGetChart(s[i], &pStarti, &pEndi));
2259:           if ((p < pStarti) || (p >= pEndi)) continue;
2260:           for (fi = 0; fi < nf; ++fi, ++f) {
2261:             PetscCall(PetscSectionGetFieldDof(s[i], p, fi, &fdof));
2262:             PetscCall(PetscSectionGetFieldConstraintDof(s[i], p, fi, &cfdof));
2263:             PetscCall(PetscSectionGetFieldConstraintIndices(s[i], p, fi, &oldIndices));
2264:             for (fc = 0; fc < cfdof; ++fc) indices[numConst + fc] = oldIndices[fc];
2265:             PetscCall(PetscSectionSetFieldConstraintIndices(*supers, p, f, &indices[numConst]));
2266:             for (fc = 0; fc < cfdof; ++fc) indices[numConst + fc] += fOff;
2267:             numConst += cfdof;
2268:           }
2269:           PetscCall(PetscSectionGetDof(s[i], p, &dof));
2270:           fOff += dof;
2271:         }
2272:         PetscCall(PetscSectionSetConstraintIndices(*supers, p, indices));
2273:       }
2274:     }
2275:     PetscCall(PetscFree(indices));
2276:   }
2277:   PetscFunctionReturn(PETSC_SUCCESS);
2278: }

2280: static PetscErrorCode PetscSectionCreateSubplexSection_Private(PetscSection s, IS subpointIS, PetscBool renumberPoints, PetscSection *subs)
2281: {
2282:   const PetscInt *points = NULL, *indices = NULL;
2283:   PetscInt       *spoints = NULL, *order = NULL;
2284:   PetscInt        numFields, f, c, numSubpoints = 0, pStart, pEnd, p, spStart, spEnd, subp;

2286:   PetscFunctionBegin;
2289:   PetscAssertPointer(subs, 4);
2290:   PetscCall(PetscSectionGetNumFields(s, &numFields));
2291:   PetscCall(PetscSectionCreate(PetscObjectComm((PetscObject)s), subs));
2292:   if (numFields) PetscCall(PetscSectionSetNumFields(*subs, numFields));
2293:   for (f = 0; f < numFields; ++f) {
2294:     const char *name    = NULL;
2295:     PetscInt    numComp = 0;

2297:     PetscCall(PetscSectionGetFieldName(s, f, &name));
2298:     PetscCall(PetscSectionSetFieldName(*subs, f, name));
2299:     PetscCall(PetscSectionGetFieldComponents(s, f, &numComp));
2300:     PetscCall(PetscSectionSetFieldComponents(*subs, f, numComp));
2301:     for (c = 0; c < s->numFieldComponents[f]; ++c) {
2302:       PetscCall(PetscSectionGetComponentName(s, f, c, &name));
2303:       PetscCall(PetscSectionSetComponentName(*subs, f, c, name));
2304:     }
2305:   }
2306:   /* For right now, we do not try to squeeze the subchart */
2307:   if (subpointIS) {
2308:     PetscCall(ISGetLocalSize(subpointIS, &numSubpoints));
2309:     PetscCall(ISGetIndices(subpointIS, &points));
2310:   }
2311:   PetscCall(PetscSectionGetChart(s, &pStart, &pEnd));
2312:   if (renumberPoints) {
2313:     PetscBool sorted;

2315:     spStart = 0;
2316:     spEnd   = numSubpoints;
2317:     PetscCall(ISSorted(subpointIS, &sorted));
2318:     if (!sorted) {
2319:       PetscCall(PetscMalloc2(numSubpoints, &spoints, numSubpoints, &order));
2320:       PetscCall(PetscArraycpy(spoints, points, numSubpoints));
2321:       for (PetscInt i = 0; i < numSubpoints; ++i) order[i] = i;
2322:       PetscCall(PetscSortIntWithArray(numSubpoints, spoints, order));
2323:     }
2324:   } else {
2325:     PetscCall(ISGetMinMax(subpointIS, &spStart, &spEnd));
2326:     ++spEnd;
2327:   }
2328:   PetscCall(PetscSectionSetChart(*subs, spStart, spEnd));
2329:   for (p = pStart; p < pEnd; ++p) {
2330:     PetscInt dof, cdof, fdof = 0, cfdof = 0;

2332:     PetscCall(PetscFindInt(p, numSubpoints, spoints ? spoints : points, &subp));
2333:     if (subp < 0) continue;
2334:     if (!renumberPoints) subp = p;
2335:     else subp = order ? order[subp] : subp;
2336:     for (f = 0; f < numFields; ++f) {
2337:       PetscCall(PetscSectionGetFieldDof(s, p, f, &fdof));
2338:       PetscCall(PetscSectionSetFieldDof(*subs, subp, f, fdof));
2339:       PetscCall(PetscSectionGetFieldConstraintDof(s, p, f, &cfdof));
2340:       if (cfdof) PetscCall(PetscSectionSetFieldConstraintDof(*subs, subp, f, cfdof));
2341:     }
2342:     PetscCall(PetscSectionGetDof(s, p, &dof));
2343:     PetscCall(PetscSectionSetDof(*subs, subp, dof));
2344:     PetscCall(PetscSectionGetConstraintDof(s, p, &cdof));
2345:     if (cdof) PetscCall(PetscSectionSetConstraintDof(*subs, subp, cdof));
2346:   }
2347:   PetscCall(PetscSectionSetUp(*subs));
2348:   /* Change offsets to original offsets */
2349:   for (p = pStart; p < pEnd; ++p) {
2350:     PetscInt off, foff = 0;

2352:     PetscCall(PetscFindInt(p, numSubpoints, spoints ? spoints : points, &subp));
2353:     if (subp < 0) continue;
2354:     if (!renumberPoints) subp = p;
2355:     else subp = order ? order[subp] : subp;
2356:     for (f = 0; f < numFields; ++f) {
2357:       PetscCall(PetscSectionGetFieldOffset(s, p, f, &foff));
2358:       PetscCall(PetscSectionSetFieldOffset(*subs, subp, f, foff));
2359:     }
2360:     PetscCall(PetscSectionGetOffset(s, p, &off));
2361:     PetscCall(PetscSectionSetOffset(*subs, subp, off));
2362:   }
2363:   /* Copy constraint indices */
2364:   for (subp = spStart; subp < spEnd; ++subp) {
2365:     PetscInt cdof;

2367:     PetscCall(PetscSectionGetConstraintDof(*subs, subp, &cdof));
2368:     if (cdof) {
2369:       for (f = 0; f < numFields; ++f) {
2370:         PetscCall(PetscSectionGetFieldConstraintIndices(s, points[subp - spStart], f, &indices));
2371:         PetscCall(PetscSectionSetFieldConstraintIndices(*subs, subp, f, indices));
2372:       }
2373:       PetscCall(PetscSectionGetConstraintIndices(s, points[subp - spStart], &indices));
2374:       PetscCall(PetscSectionSetConstraintIndices(*subs, subp, indices));
2375:     }
2376:   }
2377:   if (subpointIS) PetscCall(ISRestoreIndices(subpointIS, &points));
2378:   PetscCall(PetscFree2(spoints, order));
2379:   PetscFunctionReturn(PETSC_SUCCESS);
2380: }

2382: /*@
2383:   PetscSectionCreateSubmeshSection - Create a new, smaller section with support on the submesh

2385:   Collective

2387:   Input Parameters:
2388: + s          - the `PetscSection`
2389: - subpointIS - a sorted list of points in the original mesh which are in the submesh

2391:   Output Parameter:
2392: . subs - the subsection

2394:   Level: advanced

2396:   Notes:
2397:   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))`

2399:   Compare this with `PetscSectionCreateSubdomainSection()` that does not map the points numbers to start at zero but leaves them as before

2401:   Developer Notes:
2402:   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`

2404: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionCreateSubdomainSection()`, `PetscSectionCreateSubsection()`, `DMPlexGetSubpointMap()`, `PetscSectionCreate()`
2405: @*/
2406: PetscErrorCode PetscSectionCreateSubmeshSection(PetscSection s, IS subpointIS, PetscSection *subs)
2407: {
2408:   PetscFunctionBegin;
2409:   PetscCall(PetscSectionCreateSubplexSection_Private(s, subpointIS, PETSC_TRUE, subs));
2410:   PetscFunctionReturn(PETSC_SUCCESS);
2411: }

2413: /*@
2414:   PetscSectionCreateSubdomainSection - Create a new, smaller section with support on a subdomain of the mesh

2416:   Collective

2418:   Input Parameters:
2419: + s           - the `PetscSection`
2420: - subpointMap - a sorted list of points in the original mesh which are in the subdomain

2422:   Output Parameter:
2423: . subs - the subsection

2425:   Level: advanced

2427:   Notes:
2428:   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`
2429:   is `[min(subpointMap),max(subpointMap)+1)`

2431:   Compare this with `PetscSectionCreateSubmeshSection()` that maps the point numbers to start at zero

2433:   Developer Notes:
2434:   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`

2436: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionCreateSubmeshSection()`, `PetscSectionCreateSubsection()`, `DMPlexGetSubpointMap()`, `PetscSectionCreate()`
2437: @*/
2438: PetscErrorCode PetscSectionCreateSubdomainSection(PetscSection s, IS subpointMap, PetscSection *subs)
2439: {
2440:   PetscFunctionBegin;
2441:   PetscCall(PetscSectionCreateSubplexSection_Private(s, subpointMap, PETSC_FALSE, subs));
2442:   PetscFunctionReturn(PETSC_SUCCESS);
2443: }

2445: static PetscErrorCode PetscSectionView_ASCII(PetscSection s, PetscViewer viewer)
2446: {
2447:   PetscInt    p;
2448:   PetscMPIInt rank;

2450:   PetscFunctionBegin;
2451:   PetscCallMPI(MPI_Comm_rank(PetscObjectComm((PetscObject)viewer), &rank));
2452:   PetscCall(PetscViewerASCIIPushSynchronized(viewer));
2453:   PetscCall(PetscViewerASCIISynchronizedPrintf(viewer, "Process %d:\n", rank));
2454:   for (p = 0; p < s->pEnd - s->pStart; ++p) {
2455:     if (s->bc && s->bc->atlasDof[p] > 0) {
2456:       PetscInt b;
2457:       PetscCall(PetscViewerASCIISynchronizedPrintf(viewer, "  (%4" PetscInt_FMT ") dof %2" PetscInt_FMT " offset %3" PetscInt_FMT " constrained", p + s->pStart, s->atlasDof[p], s->atlasOff[p]));
2458:       if (s->bcIndices) {
2459:         for (b = 0; b < s->bc->atlasDof[p]; ++b) PetscCall(PetscViewerASCIISynchronizedPrintf(viewer, " %" PetscInt_FMT, s->bcIndices[s->bc->atlasOff[p] + b]));
2460:       }
2461:       PetscCall(PetscViewerASCIISynchronizedPrintf(viewer, "\n"));
2462:     } else {
2463:       PetscCall(PetscViewerASCIISynchronizedPrintf(viewer, "  (%4" PetscInt_FMT ") dof %2" PetscInt_FMT " offset %3" PetscInt_FMT "\n", p + s->pStart, s->atlasDof[p], s->atlasOff[p]));
2464:     }
2465:   }
2466:   PetscCall(PetscViewerFlush(viewer));
2467:   PetscCall(PetscViewerASCIIPopSynchronized(viewer));
2468:   if (s->sym) {
2469:     PetscCall(PetscViewerASCIIPushTab(viewer));
2470:     PetscCall(PetscSectionSymView(s->sym, viewer));
2471:     PetscCall(PetscViewerASCIIPopTab(viewer));
2472:   }
2473:   PetscFunctionReturn(PETSC_SUCCESS);
2474: }

2476: /*@
2477:   PetscSectionViewFromOptions - View the `PetscSection` based on values in the options database

2479:   Collective

2481:   Input Parameters:
2482: + A    - the `PetscSection` object to view
2483: . obj  - Optional object that provides the options prefix used for the options
2484: - name - command line option

2486:   Level: intermediate

2488:   Note:
2489:   See `PetscObjectViewFromOptions()` for available values of `PetscViewer` and `PetscViewerFormat`

2491: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionView`, `PetscObjectViewFromOptions()`, `PetscSectionCreate()`, `PetscSectionView()`
2492: @*/
2493: PetscErrorCode PetscSectionViewFromOptions(PetscSection A, PetscObject obj, const char name[])
2494: {
2495:   PetscFunctionBegin;
2497:   PetscCall(PetscObjectViewFromOptions((PetscObject)A, obj, name));
2498:   PetscFunctionReturn(PETSC_SUCCESS);
2499: }

2501: /*@
2502:   PetscSectionView - Views a `PetscSection`

2504:   Collective

2506:   Input Parameters:
2507: + s      - the `PetscSection` object to view
2508: - viewer - the viewer

2510:   Level: beginner

2512:   Note:
2513:   `PetscSectionView()`, when viewer is of type `PETSCVIEWERHDF5`, only saves
2514:   distribution independent data, such as dofs, offsets, constraint dofs,
2515:   and constraint indices. Points that have negative dofs, for instance,
2516:   are not saved as they represent points owned by other processes.
2517:   Point numbering and rank assignment is currently not stored.
2518:   The saved section can be loaded with `PetscSectionLoad()`.

2520: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionCreate()`, `PetscSectionDestroy()`, `PetscSectionLoad()`, `PetscViewer`
2521: @*/
2522: PetscErrorCode PetscSectionView(PetscSection s, PetscViewer viewer)
2523: {
2524:   PetscBool isascii, ishdf5;
2525:   PetscInt  f;

2527:   PetscFunctionBegin;
2529:   if (!viewer) PetscCall(PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)s), &viewer));
2531:   PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERASCII, &isascii));
2532:   PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERHDF5, &ishdf5));
2533:   if (isascii) {
2534:     PetscCall(PetscObjectPrintClassNamePrefixType((PetscObject)s, viewer));
2535:     if (s->numFields) {
2536:       PetscCall(PetscViewerASCIIPrintf(viewer, "%" PetscInt_FMT " fields\n", s->numFields));
2537:       for (f = 0; f < s->numFields; ++f) {
2538:         PetscCall(PetscViewerASCIIPrintf(viewer, "  field %" PetscInt_FMT " \"%s\" with %" PetscInt_FMT " components\n", f, s->fieldNames[f], s->numFieldComponents[f]));
2539:         PetscCall(PetscSectionView_ASCII(s->field[f], viewer));
2540:       }
2541:     } else {
2542:       PetscCall(PetscSectionView_ASCII(s, viewer));
2543:     }
2544:   } else if (ishdf5) {
2545: #if PetscDefined(HAVE_HDF5)
2546:     PetscCall(PetscSectionView_HDF5_Internal(s, viewer));
2547: #else
2548:     SETERRQ(PetscObjectComm((PetscObject)s), PETSC_ERR_SUP, "HDF5 not supported in this build.\nPlease reconfigure using --download-hdf5");
2549: #endif
2550:   }
2551:   PetscFunctionReturn(PETSC_SUCCESS);
2552: }

2554: /*@
2555:   PetscSectionLoad - Loads a `PetscSection`

2557:   Collective

2559:   Input Parameters:
2560: + s      - the `PetscSection` object to load
2561: - viewer - the viewer

2563:   Level: beginner

2565:   Note:
2566:   `PetscSectionLoad()`, when viewer is of type `PETSCVIEWERHDF5`, loads
2567:   a section saved with `PetscSectionView()`. The number of processes
2568:   used here (N) does not need to be the same as that used when saving.
2569:   After calling this function, the chart of s on rank i will be set
2570:   to [0, E_i), where \sum_{i=0}^{N-1}E_i equals to the total number of
2571:   saved section points.

2573: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionCreate()`, `PetscSectionDestroy()`, `PetscSectionView()`
2574: @*/
2575: PetscErrorCode PetscSectionLoad(PetscSection s, PetscViewer viewer)
2576: {
2577:   PetscBool ishdf5;

2579:   PetscFunctionBegin;
2582:   PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERHDF5, &ishdf5));
2583:   if (ishdf5) {
2584: #if PetscDefined(HAVE_HDF5)
2585:     PetscCall(PetscSectionLoad_HDF5_Internal(s, viewer));
2586:     PetscFunctionReturn(PETSC_SUCCESS);
2587: #else
2588:     SETERRQ(PetscObjectComm((PetscObject)s), PETSC_ERR_SUP, "HDF5 not supported in this build.\nPlease reconfigure using --download-hdf5");
2589: #endif
2590:   } else SETERRQ(PetscObjectComm((PetscObject)s), PETSC_ERR_SUP, "Viewer type %s not yet supported for PetscSection loading", ((PetscObject)viewer)->type_name);
2591: }

2593: /*@
2594:   PetscSectionResetClosurePermutation - Remove any existing closure permutation

2596:   Input Parameter:
2597: . section - The `PetscSection`

2599:   Level: intermediate

2601: .seealso: `PetscSectionSetClosurePermutation()`, `PetscSectionSetClosureIndex()`, `PetscSectionReset()`
2602: @*/
2603: PetscErrorCode PetscSectionResetClosurePermutation(PetscSection section)
2604: {
2605:   PetscSectionClosurePermVal clVal;

2607:   PetscFunctionBegin;
2608:   if (!section->clHash) PetscFunctionReturn(PETSC_SUCCESS);
2609:   kh_foreach_value(section->clHash, clVal, {
2610:     PetscCall(PetscFree(clVal.perm));
2611:     PetscCall(PetscFree(clVal.invPerm));
2612:   });
2613:   kh_destroy(ClPerm, section->clHash);
2614:   section->clHash = NULL;
2615:   PetscFunctionReturn(PETSC_SUCCESS);
2616: }

2618: /*@
2619:   PetscSectionReset - Frees all section data, the section is then as if `PetscSectionCreate()` had just been called.

2621:   Not Collective

2623:   Input Parameter:
2624: . s - the `PetscSection`

2626:   Level: beginner

2628: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionCreate()`
2629: @*/
2630: PetscErrorCode PetscSectionReset(PetscSection s)
2631: {
2632:   PetscInt f, c;

2634:   PetscFunctionBegin;
2636:   for (f = 0; f < s->numFields; ++f) {
2637:     PetscCall(PetscSectionDestroy(&s->field[f]));
2638:     PetscCall(PetscFree(s->fieldNames[f]));
2639:     for (c = 0; c < s->numFieldComponents[f]; ++c) PetscCall(PetscFree(s->compNames[f][c]));
2640:     PetscCall(PetscFree(s->compNames[f]));
2641:   }
2642:   PetscCall(PetscFree(s->numFieldComponents));
2643:   PetscCall(PetscFree(s->fieldNames));
2644:   PetscCall(PetscFree(s->compNames));
2645:   PetscCall(PetscFree(s->field));
2646:   PetscCall(PetscSectionDestroy(&s->bc));
2647:   PetscCall(PetscFree(s->bcIndices));
2648:   PetscCall(PetscFree2(s->atlasDof, s->atlasOff));
2649:   PetscCall(PetscSectionDestroy(&s->clSection));
2650:   PetscCall(ISDestroy(&s->clPoints));
2651:   PetscCall(ISDestroy(&s->perm));
2652:   PetscCall(PetscBTDestroy(&s->blockStarts));
2653:   PetscCall(PetscSectionResetClosurePermutation(s));
2654:   PetscCall(PetscSectionSymDestroy(&s->sym));
2655:   PetscCall(PetscSectionDestroy(&s->clSection));
2656:   PetscCall(ISDestroy(&s->clPoints));
2657:   PetscCall(PetscSectionInvalidateMaxDof_Internal(s));
2658:   s->pStart    = -1;
2659:   s->pEnd      = -1;
2660:   s->maxDof    = 0;
2661:   s->setup     = PETSC_FALSE;
2662:   s->numFields = 0;
2663:   s->clObj     = NULL;
2664:   PetscFunctionReturn(PETSC_SUCCESS);
2665: }

2667: /*@
2668:   PetscSectionDestroy - Frees a `PetscSection`

2670:   Not Collective

2672:   Input Parameter:
2673: . s - the `PetscSection`

2675:   Level: beginner

2677: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionCreate()`, `PetscSectionReset()`
2678: @*/
2679: PetscErrorCode PetscSectionDestroy(PetscSection *s)
2680: {
2681:   PetscFunctionBegin;
2682:   if (!*s) PetscFunctionReturn(PETSC_SUCCESS);
2684:   if (--((PetscObject)*s)->refct > 0) {
2685:     *s = NULL;
2686:     PetscFunctionReturn(PETSC_SUCCESS);
2687:   }
2688:   PetscCall(PetscSectionReset(*s));
2689:   PetscCall(PetscHeaderDestroy(s));
2690:   PetscFunctionReturn(PETSC_SUCCESS);
2691: }

2693: static PetscErrorCode VecIntGetValuesSection_Private(const PetscInt *baseArray, PetscSection s, PetscInt point, const PetscInt **values)
2694: {
2695:   const PetscInt p = point - s->pStart;

2697:   PetscFunctionBegin;
2699:   *values = &baseArray[s->atlasOff[p]];
2700:   PetscFunctionReturn(PETSC_SUCCESS);
2701: }

2703: static PetscErrorCode VecIntSetValuesSection_Private(PetscInt *baseArray, PetscSection s, PetscInt point, const PetscInt values[], InsertMode mode)
2704: {
2705:   PetscInt      *array;
2706:   const PetscInt p           = point - s->pStart;
2707:   const PetscInt orientation = 0; /* Needs to be included for use in closure operations */
2708:   PetscInt       cDim        = 0;

2710:   PetscFunctionBegin;
2712:   PetscCall(PetscSectionGetConstraintDof(s, p, &cDim));
2713:   array = &baseArray[s->atlasOff[p]];
2714:   if (!cDim) {
2715:     if (orientation >= 0) {
2716:       const PetscInt dim = s->atlasDof[p];
2717:       PetscInt       i;

2719:       if (mode == INSERT_VALUES) {
2720:         for (i = 0; i < dim; ++i) array[i] = values ? values[i] : i;
2721:       } else {
2722:         for (i = 0; i < dim; ++i) array[i] += values[i];
2723:       }
2724:     } else {
2725:       PetscInt offset = 0;
2726:       PetscInt j      = -1, field, i;

2728:       for (field = 0; field < s->numFields; ++field) {
2729:         const PetscInt dim = s->field[field]->atlasDof[p];

2731:         for (i = dim - 1; i >= 0; --i) array[++j] = values ? values[i + offset] : i + offset;
2732:         offset += dim;
2733:       }
2734:     }
2735:   } else {
2736:     if (orientation >= 0) {
2737:       const PetscInt  dim  = s->atlasDof[p];
2738:       PetscInt        cInd = 0, i;
2739:       const PetscInt *cDof;

2741:       PetscCall(PetscSectionGetConstraintIndices(s, point, &cDof));
2742:       if (mode == INSERT_VALUES) {
2743:         for (i = 0; i < dim; ++i) {
2744:           if ((cInd < cDim) && (i == cDof[cInd])) {
2745:             ++cInd;
2746:             continue;
2747:           }
2748:           array[i] = values ? values[i] : i;
2749:         }
2750:       } else {
2751:         for (i = 0; i < dim; ++i) {
2752:           if ((cInd < cDim) && (i == cDof[cInd])) {
2753:             ++cInd;
2754:             continue;
2755:           }
2756:           array[i] += values[i];
2757:         }
2758:       }
2759:     } else {
2760:       const PetscInt *cDof;
2761:       PetscInt        offset  = 0;
2762:       PetscInt        cOffset = 0;
2763:       PetscInt        j       = 0, field;

2765:       PetscCall(PetscSectionGetConstraintIndices(s, point, &cDof));
2766:       for (field = 0; field < s->numFields; ++field) {
2767:         const PetscInt dim  = s->field[field]->atlasDof[p];     /* PetscSectionGetFieldDof() */
2768:         const PetscInt tDim = s->field[field]->bc->atlasDof[p]; /* PetscSectionGetFieldConstraintDof() */
2769:         const PetscInt sDim = dim - tDim;
2770:         PetscInt       cInd = 0, i, k;

2772:         for (i = 0, k = dim + offset - 1; i < dim; ++i, ++j, --k) {
2773:           if ((cInd < sDim) && (j == cDof[cInd + cOffset])) {
2774:             ++cInd;
2775:             continue;
2776:           }
2777:           array[j] = values ? values[k] : k;
2778:         }
2779:         offset += dim;
2780:         cOffset += dim - tDim;
2781:       }
2782:     }
2783:   }
2784:   PetscFunctionReturn(PETSC_SUCCESS);
2785: }

2787: /*@
2788:   PetscSectionHasConstraints - Determine whether a `PetscSection` has constrained dofs

2790:   Not Collective

2792:   Input Parameter:
2793: . s - The `PetscSection`

2795:   Output Parameter:
2796: . hasConstraints - flag indicating that the section has constrained dofs

2798:   Level: intermediate

2800: .seealso: [PetscSection](sec_petscsection), `PetscSectionSetConstraintIndices()`, `PetscSectionGetConstraintDof()`, `PetscSection`
2801: @*/
2802: PetscErrorCode PetscSectionHasConstraints(PetscSection s, PetscBool *hasConstraints)
2803: {
2804:   PetscFunctionBegin;
2806:   PetscAssertPointer(hasConstraints, 2);
2807:   *hasConstraints = s->bc ? PETSC_TRUE : PETSC_FALSE;
2808:   PetscFunctionReturn(PETSC_SUCCESS);
2809: }

2811: /*@C
2812:   PetscSectionGetConstraintIndices - Get the point dof numbers, in [0, dof), which are constrained for a given point

2814:   Not Collective

2816:   Input Parameters:
2817: + s     - The `PetscSection`
2818: - point - The point

2820:   Output Parameter:
2821: . indices - The constrained dofs

2823:   Level: intermediate

2825:   Fortran Notes:
2826:   Use `PetscSectionGetConstraintIndicesF90()` and `PetscSectionRestoreConstraintIndicesF90()`

2828: .seealso: [PetscSection](sec_petscsection), `PetscSectionSetConstraintIndices()`, `PetscSectionGetConstraintDof()`, `PetscSection`
2829: @*/
2830: PetscErrorCode PetscSectionGetConstraintIndices(PetscSection s, PetscInt point, const PetscInt *indices[])
2831: {
2832:   PetscFunctionBegin;
2834:   if (s->bc) {
2835:     PetscCall(VecIntGetValuesSection_Private(s->bcIndices, s->bc, point, indices));
2836:   } else *indices = NULL;
2837:   PetscFunctionReturn(PETSC_SUCCESS);
2838: }

2840: /*@
2841:   PetscSectionSetConstraintIndices - Set the point dof numbers, in [0, dof), which are constrained

2843:   Not Collective

2845:   Input Parameters:
2846: + s       - The `PetscSection`
2847: . point   - The point
2848: - indices - The constrained dofs

2850:   Level: intermediate

2852:   Fortran Notes:
2853:   Use `PetscSectionSetConstraintIndicesF90()`

2855: .seealso: [PetscSection](sec_petscsection), `PetscSectionGetConstraintIndices()`, `PetscSectionGetConstraintDof()`, `PetscSection`
2856: @*/
2857: PetscErrorCode PetscSectionSetConstraintIndices(PetscSection s, PetscInt point, const PetscInt indices[])
2858: {
2859:   PetscFunctionBegin;
2861:   if (s->bc) {
2862:     const PetscInt dof  = s->atlasDof[point];
2863:     const PetscInt cdof = s->bc->atlasDof[point];
2864:     PetscInt       d;

2866:     if (indices)
2867:       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]);
2868:     PetscCall(VecIntSetValuesSection_Private(s->bcIndices, s->bc, point, indices, INSERT_VALUES));
2869:   }
2870:   PetscFunctionReturn(PETSC_SUCCESS);
2871: }

2873: /*@C
2874:   PetscSectionGetFieldConstraintIndices - Get the field dof numbers, in [0, fdof), which are constrained

2876:   Not Collective

2878:   Input Parameters:
2879: + s     - The `PetscSection`
2880: . field - The field number
2881: - point - The point

2883:   Output Parameter:
2884: . indices - The constrained dofs sorted in ascending order

2886:   Level: intermediate

2888:   Note:
2889:   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()`.

2891:   Fortran Notes:
2892:   Use `PetscSectionGetFieldConstraintIndicesF90()` and `PetscSectionRestoreFieldConstraintIndicesF90()`

2894: .seealso: [PetscSection](sec_petscsection), `PetscSectionSetFieldConstraintIndices()`, `PetscSectionGetConstraintIndices()`, `PetscSectionGetConstraintDof()`, `PetscSection`
2895: @*/
2896: PetscErrorCode PetscSectionGetFieldConstraintIndices(PetscSection s, PetscInt point, PetscInt field, const PetscInt **indices)
2897: {
2898:   PetscFunctionBegin;
2900:   PetscAssertPointer(indices, 4);
2901:   PetscSectionCheckValidField(field, s->numFields);
2902:   PetscCall(PetscSectionGetConstraintIndices(s->field[field], point, indices));
2903:   PetscFunctionReturn(PETSC_SUCCESS);
2904: }

2906: /*@C
2907:   PetscSectionSetFieldConstraintIndices - Set the field dof numbers, in [0, fdof), which are constrained

2909:   Not Collective

2911:   Input Parameters:
2912: + s       - The `PetscSection`
2913: . point   - The point
2914: . field   - The field number
2915: - indices - The constrained dofs

2917:   Level: intermediate

2919:   Fortran Notes:
2920:   Use `PetscSectionSetFieldConstraintIndicesF90()`

2922: .seealso: [PetscSection](sec_petscsection), `PetscSectionSetConstraintIndices()`, `PetscSectionGetFieldConstraintIndices()`, `PetscSectionGetConstraintDof()`, `PetscSection`
2923: @*/
2924: PetscErrorCode PetscSectionSetFieldConstraintIndices(PetscSection s, PetscInt point, PetscInt field, const PetscInt indices[])
2925: {
2926:   PetscFunctionBegin;
2928:   PetscSectionCheckValidField(field, s->numFields);
2929:   PetscCall(PetscSectionSetConstraintIndices(s->field[field], point, indices));
2930:   PetscFunctionReturn(PETSC_SUCCESS);
2931: }

2933: /*@
2934:   PetscSectionPermute - Reorder the section according to the input point permutation

2936:   Collective

2938:   Input Parameters:
2939: + section     - The `PetscSection` object
2940: - permutation - The point permutation, old point p becomes new point perm[p]

2942:   Output Parameter:
2943: . sectionNew - The permuted `PetscSection`

2945:   Level: intermediate

2947:   Note:
2948:   The data and the access to the data via `PetscSectionGetFieldOffset()` and `PetscSectionGetOffset()` are both changed in `sectionNew`

2950:   Compare to `PetscSectionSetPermutation()`

2952: .seealso: [PetscSection](sec_petscsection), `IS`, `PetscSection`, `MatPermute()`, `PetscSectionSetPermutation()`
2953: @*/
2954: PetscErrorCode PetscSectionPermute(PetscSection section, IS permutation, PetscSection *sectionNew)
2955: {
2956:   PetscSection    s = section, sNew;
2957:   const PetscInt *perm;
2958:   PetscInt        numFields, f, c, numPoints, pStart, pEnd, p;

2960:   PetscFunctionBegin;
2963:   PetscAssertPointer(sectionNew, 3);
2964:   PetscCall(PetscSectionCreate(PetscObjectComm((PetscObject)s), &sNew));
2965:   PetscCall(PetscSectionGetNumFields(s, &numFields));
2966:   if (numFields) PetscCall(PetscSectionSetNumFields(sNew, numFields));
2967:   for (f = 0; f < numFields; ++f) {
2968:     const char *name;
2969:     PetscInt    numComp;

2971:     PetscCall(PetscSectionGetFieldName(s, f, &name));
2972:     PetscCall(PetscSectionSetFieldName(sNew, f, name));
2973:     PetscCall(PetscSectionGetFieldComponents(s, f, &numComp));
2974:     PetscCall(PetscSectionSetFieldComponents(sNew, f, numComp));
2975:     for (c = 0; c < s->numFieldComponents[f]; ++c) {
2976:       PetscCall(PetscSectionGetComponentName(s, f, c, &name));
2977:       PetscCall(PetscSectionSetComponentName(sNew, f, c, name));
2978:     }
2979:   }
2980:   PetscCall(ISGetLocalSize(permutation, &numPoints));
2981:   PetscCall(ISGetIndices(permutation, &perm));
2982:   PetscCall(PetscSectionGetChart(s, &pStart, &pEnd));
2983:   PetscCall(PetscSectionSetChart(sNew, pStart, pEnd));
2984:   PetscCheck(numPoints >= pEnd, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Permutation size %" PetscInt_FMT " is less than largest Section point %" PetscInt_FMT, numPoints, pEnd);
2985:   for (p = pStart; p < pEnd; ++p) {
2986:     PetscInt dof, cdof;

2988:     PetscCall(PetscSectionGetDof(s, p, &dof));
2989:     PetscCall(PetscSectionSetDof(sNew, perm[p], dof));
2990:     PetscCall(PetscSectionGetConstraintDof(s, p, &cdof));
2991:     if (cdof) PetscCall(PetscSectionSetConstraintDof(sNew, perm[p], cdof));
2992:     for (f = 0; f < numFields; ++f) {
2993:       PetscCall(PetscSectionGetFieldDof(s, p, f, &dof));
2994:       PetscCall(PetscSectionSetFieldDof(sNew, perm[p], f, dof));
2995:       PetscCall(PetscSectionGetFieldConstraintDof(s, p, f, &cdof));
2996:       if (cdof) PetscCall(PetscSectionSetFieldConstraintDof(sNew, perm[p], f, cdof));
2997:     }
2998:   }
2999:   PetscCall(PetscSectionSetUp(sNew));
3000:   for (p = pStart; p < pEnd; ++p) {
3001:     const PetscInt *cind;
3002:     PetscInt        cdof;

3004:     PetscCall(PetscSectionGetConstraintDof(s, p, &cdof));
3005:     if (cdof) {
3006:       PetscCall(PetscSectionGetConstraintIndices(s, p, &cind));
3007:       PetscCall(PetscSectionSetConstraintIndices(sNew, perm[p], cind));
3008:     }
3009:     for (f = 0; f < numFields; ++f) {
3010:       PetscCall(PetscSectionGetFieldConstraintDof(s, p, f, &cdof));
3011:       if (cdof) {
3012:         PetscCall(PetscSectionGetFieldConstraintIndices(s, p, f, &cind));
3013:         PetscCall(PetscSectionSetFieldConstraintIndices(sNew, perm[p], f, cind));
3014:       }
3015:     }
3016:   }
3017:   PetscCall(ISRestoreIndices(permutation, &perm));
3018:   *sectionNew = sNew;
3019:   PetscFunctionReturn(PETSC_SUCCESS);
3020: }

3022: /*@
3023:   PetscSectionSetClosureIndex - Create an internal data structure to speed up closure queries.

3025:   Collective

3027:   Input Parameters:
3028: + section   - The `PetscSection`
3029: . obj       - A `PetscObject` which serves as the key for this index
3030: . clSection - `PetscSection` giving the size of the closure of each point
3031: - clPoints  - `IS` giving the points in each closure

3033:   Level: advanced

3035:   Note:
3036:   This function creates an internal map from each point to its closure. We compress out closure points with no dofs in this section.

3038:   Developer Notes:
3039:   The information provided here is completely opaque

3041: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionGetClosureIndex()`, `DMPlexCreateClosureIndex()`
3042: @*/
3043: PetscErrorCode PetscSectionSetClosureIndex(PetscSection section, PetscObject obj, PetscSection clSection, IS clPoints)
3044: {
3045:   PetscFunctionBegin;
3049:   if (section->clObj != obj) PetscCall(PetscSectionResetClosurePermutation(section));
3050:   section->clObj = obj;
3051:   PetscCall(PetscObjectReference((PetscObject)clSection));
3052:   PetscCall(PetscObjectReference((PetscObject)clPoints));
3053:   PetscCall(PetscSectionDestroy(&section->clSection));
3054:   PetscCall(ISDestroy(&section->clPoints));
3055:   section->clSection = clSection;
3056:   section->clPoints  = clPoints;
3057:   PetscFunctionReturn(PETSC_SUCCESS);
3058: }

3060: /*@
3061:   PetscSectionGetClosureIndex - Get the cache of points in the closure of each point in the section set with `PetscSectionSetClosureIndex()`

3063:   Collective

3065:   Input Parameters:
3066: + section - The `PetscSection`
3067: - obj     - A `PetscObject` which serves as the key for this index

3069:   Output Parameters:
3070: + clSection - `PetscSection` giving the size of the closure of each point
3071: - clPoints  - `IS` giving the points in each closure

3073:   Level: advanced

3075: .seealso: [PetscSection](sec_petscsection), `PetscSectionSetClosureIndex()`, `DMPlexCreateClosureIndex()`
3076: @*/
3077: PetscErrorCode PetscSectionGetClosureIndex(PetscSection section, PetscObject obj, PetscSection *clSection, IS *clPoints)
3078: {
3079:   PetscFunctionBegin;
3080:   if (section->clObj == obj) {
3081:     if (clSection) *clSection = section->clSection;
3082:     if (clPoints) *clPoints = section->clPoints;
3083:   } else {
3084:     if (clSection) *clSection = NULL;
3085:     if (clPoints) *clPoints = NULL;
3086:   }
3087:   PetscFunctionReturn(PETSC_SUCCESS);
3088: }

3090: PetscErrorCode PetscSectionSetClosurePermutation_Internal(PetscSection section, PetscObject obj, PetscInt depth, PetscInt clSize, PetscCopyMode mode, PetscInt *clPerm)
3091: {
3092:   PetscInt                    i;
3093:   khiter_t                    iter;
3094:   int                         new_entry;
3095:   PetscSectionClosurePermKey  key = {depth, clSize};
3096:   PetscSectionClosurePermVal *val;

3098:   PetscFunctionBegin;
3099:   if (section->clObj != obj) {
3100:     PetscCall(PetscSectionDestroy(&section->clSection));
3101:     PetscCall(ISDestroy(&section->clPoints));
3102:   }
3103:   section->clObj = obj;
3104:   if (!section->clHash) PetscCall(PetscClPermCreate(&section->clHash));
3105:   iter = kh_put(ClPerm, section->clHash, key, &new_entry);
3106:   val  = &kh_val(section->clHash, iter);
3107:   if (!new_entry) {
3108:     PetscCall(PetscFree(val->perm));
3109:     PetscCall(PetscFree(val->invPerm));
3110:   }
3111:   if (mode == PETSC_COPY_VALUES) {
3112:     PetscCall(PetscMalloc1(clSize, &val->perm));
3113:     PetscCall(PetscArraycpy(val->perm, clPerm, clSize));
3114:   } else if (mode == PETSC_OWN_POINTER) {
3115:     val->perm = clPerm;
3116:   } else SETERRQ(PetscObjectComm(obj), PETSC_ERR_SUP, "Do not support borrowed arrays");
3117:   PetscCall(PetscMalloc1(clSize, &val->invPerm));
3118:   for (i = 0; i < clSize; ++i) val->invPerm[clPerm[i]] = i;
3119:   PetscFunctionReturn(PETSC_SUCCESS);
3120: }

3122: /*@
3123:   PetscSectionSetClosurePermutation - Set the dof permutation for the closure of each cell in the section, meaning clPerm[newIndex] = oldIndex.

3125:   Not Collective

3127:   Input Parameters:
3128: + section - The `PetscSection`
3129: . obj     - A `PetscObject` which serves as the key for this index (usually a `DM`)
3130: . depth   - Depth of points on which to apply the given permutation
3131: - perm    - Permutation of the cell dof closure

3133:   Level: intermediate

3135:   Notes:
3136:   The specified permutation will only be applied to points at depth whose closure size matches the length of perm.  In a
3137:   mixed-topology or variable-degree finite element space, this function can be called multiple times at each depth for
3138:   each topology and degree.

3140:   This approach assumes that (depth, len(perm)) uniquely identifies the desired permutation; this might not be true for
3141:   exotic/enriched spaces on mixed topology meshes.

3143: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `IS`, `PetscSectionGetClosurePermutation()`, `PetscSectionGetClosureIndex()`, `DMPlexCreateClosureIndex()`, `PetscCopyMode`
3144: @*/
3145: PetscErrorCode PetscSectionSetClosurePermutation(PetscSection section, PetscObject obj, PetscInt depth, IS perm)
3146: {
3147:   const PetscInt *clPerm = NULL;
3148:   PetscInt        clSize = 0;

3150:   PetscFunctionBegin;
3151:   if (perm) {
3152:     PetscCall(ISGetLocalSize(perm, &clSize));
3153:     PetscCall(ISGetIndices(perm, &clPerm));
3154:   }
3155:   PetscCall(PetscSectionSetClosurePermutation_Internal(section, obj, depth, clSize, PETSC_COPY_VALUES, (PetscInt *)clPerm));
3156:   if (perm) PetscCall(ISRestoreIndices(perm, &clPerm));
3157:   PetscFunctionReturn(PETSC_SUCCESS);
3158: }

3160: static PetscErrorCode PetscSectionGetClosurePermutation_Private(PetscSection section, PetscObject obj, PetscInt depth, PetscInt size, const PetscInt *perm[])
3161: {
3162:   PetscFunctionBegin;
3163:   if (section->clObj == obj) {
3164:     PetscSectionClosurePermKey k = {depth, size};
3165:     PetscSectionClosurePermVal v;

3167:     PetscCall(PetscClPermGet(section->clHash, k, &v));
3168:     if (perm) *perm = v.perm;
3169:   } else {
3170:     if (perm) *perm = NULL;
3171:   }
3172:   PetscFunctionReturn(PETSC_SUCCESS);
3173: }

3175: /*@
3176:   PetscSectionGetClosurePermutation - Get the dof permutation for the closure of each cell in the section, meaning clPerm[newIndex] = oldIndex.

3178:   Not Collective

3180:   Input Parameters:
3181: + section - The `PetscSection`
3182: . obj     - A `PetscObject` which serves as the key for this index (usually a DM)
3183: . depth   - Depth stratum on which to obtain closure permutation
3184: - clSize  - Closure size to be permuted (e.g., may vary with element topology and degree)

3186:   Output Parameter:
3187: . perm - The dof closure permutation

3189:   Level: intermediate

3191:   Note:
3192:   The user must destroy the `IS` that is returned.

3194: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `IS`, `PetscSectionSetClosurePermutation()`, `PetscSectionGetClosureInversePermutation()`, `PetscSectionGetClosureIndex()`, `PetscSectionSetClosureIndex()`, `DMPlexCreateClosureIndex()`
3195: @*/
3196: PetscErrorCode PetscSectionGetClosurePermutation(PetscSection section, PetscObject obj, PetscInt depth, PetscInt clSize, IS *perm)
3197: {
3198:   const PetscInt *clPerm = NULL;

3200:   PetscFunctionBegin;
3201:   PetscCall(PetscSectionGetClosurePermutation_Private(section, obj, depth, clSize, &clPerm));
3202:   PetscCheck(clPerm, PetscObjectComm(obj), PETSC_ERR_ARG_WRONG, "There is no closure permutation associated with this object for depth %" PetscInt_FMT " of size %" PetscInt_FMT, depth, clSize);
3203:   PetscCall(ISCreateGeneral(PETSC_COMM_SELF, clSize, clPerm, PETSC_USE_POINTER, perm));
3204:   PetscFunctionReturn(PETSC_SUCCESS);
3205: }

3207: PetscErrorCode PetscSectionGetClosureInversePermutation_Internal(PetscSection section, PetscObject obj, PetscInt depth, PetscInt size, const PetscInt *perm[])
3208: {
3209:   PetscFunctionBegin;
3210:   if (section->clObj == obj && section->clHash) {
3211:     PetscSectionClosurePermKey k = {depth, size};
3212:     PetscSectionClosurePermVal v;
3213:     PetscCall(PetscClPermGet(section->clHash, k, &v));
3214:     if (perm) *perm = v.invPerm;
3215:   } else {
3216:     if (perm) *perm = NULL;
3217:   }
3218:   PetscFunctionReturn(PETSC_SUCCESS);
3219: }

3221: /*@
3222:   PetscSectionGetClosureInversePermutation - Get the inverse dof permutation for the closure of each cell in the section, meaning clPerm[oldIndex] = newIndex.

3224:   Not Collective

3226:   Input Parameters:
3227: + section - The `PetscSection`
3228: . obj     - A `PetscObject` which serves as the key for this index (usually a `DM`)
3229: . depth   - Depth stratum on which to obtain closure permutation
3230: - clSize  - Closure size to be permuted (e.g., may vary with element topology and degree)

3232:   Output Parameter:
3233: . perm - The dof closure permutation

3235:   Level: intermediate

3237:   Note:
3238:   The user must destroy the `IS` that is returned.

3240: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `IS`, `PetscSectionSetClosurePermutation()`, `PetscSectionGetClosureIndex()`, `PetscSectionSetClosureIndex()`, `DMPlexCreateClosureIndex()`
3241: @*/
3242: PetscErrorCode PetscSectionGetClosureInversePermutation(PetscSection section, PetscObject obj, PetscInt depth, PetscInt clSize, IS *perm)
3243: {
3244:   const PetscInt *clPerm = NULL;

3246:   PetscFunctionBegin;
3247:   PetscCall(PetscSectionGetClosureInversePermutation_Internal(section, obj, depth, clSize, &clPerm));
3248:   PetscCall(ISCreateGeneral(PETSC_COMM_SELF, clSize, clPerm, PETSC_USE_POINTER, perm));
3249:   PetscFunctionReturn(PETSC_SUCCESS);
3250: }

3252: /*@
3253:   PetscSectionGetField - Get the `PetscSection` associated with a single field

3255:   Input Parameters:
3256: + s     - The `PetscSection`
3257: - field - The field number

3259:   Output Parameter:
3260: . subs - The `PetscSection` for the given field, note the chart of `subs` is not set

3262:   Level: intermediate

3264:   Note:
3265:   Does not increase the reference count of the selected sub-section. There is no matching `PetscSectionRestoreField()`

3267: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `IS`, `PetscSectionSetNumFields()`
3268: @*/
3269: PetscErrorCode PetscSectionGetField(PetscSection s, PetscInt field, PetscSection *subs)
3270: {
3271:   PetscFunctionBegin;
3273:   PetscAssertPointer(subs, 3);
3274:   PetscSectionCheckValidField(field, s->numFields);
3275:   *subs = s->field[field];
3276:   PetscFunctionReturn(PETSC_SUCCESS);
3277: }

3279: PetscClassId      PETSC_SECTION_SYM_CLASSID;
3280: PetscFunctionList PetscSectionSymList = NULL;

3282: /*@
3283:   PetscSectionSymCreate - Creates an empty `PetscSectionSym` object.

3285:   Collective

3287:   Input Parameter:
3288: . comm - the MPI communicator

3290:   Output Parameter:
3291: . sym - pointer to the new set of symmetries

3293:   Level: developer

3295: .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionSym`, `PetscSectionSymDestroy()`
3296: @*/
3297: PetscErrorCode PetscSectionSymCreate(MPI_Comm comm, PetscSectionSym *sym)
3298: {
3299:   PetscFunctionBegin;
3300:   PetscAssertPointer(sym, 2);
3301:   PetscCall(ISInitializePackage());

3303:   PetscCall(PetscHeaderCreate(*sym, PETSC_SECTION_SYM_CLASSID, "PetscSectionSym", "Section Symmetry", "IS", comm, PetscSectionSymDestroy, PetscSectionSymView));
3304:   PetscFunctionReturn(PETSC_SUCCESS);
3305: }

3307: /*@
3308:   PetscSectionSymSetType - Builds a `PetscSectionSym`, for a particular implementation.

3310:   Collective

3312:   Input Parameters:
3313: + sym    - The section symmetry object
3314: - method - The name of the section symmetry type

3316:   Level: developer

3318: .seealso: [PetscSection](sec_petscsection), `PetscSectionSym`, `PetscSectionSymType`, `PetscSectionSymGetType()`, `PetscSectionSymCreate()`
3319: @*/
3320: PetscErrorCode PetscSectionSymSetType(PetscSectionSym sym, PetscSectionSymType method)
3321: {
3322:   PetscErrorCode (*r)(PetscSectionSym);
3323:   PetscBool match;

3325:   PetscFunctionBegin;
3327:   PetscCall(PetscObjectTypeCompare((PetscObject)sym, method, &match));
3328:   if (match) PetscFunctionReturn(PETSC_SUCCESS);

3330:   PetscCall(PetscFunctionListFind(PetscSectionSymList, method, &r));
3331:   PetscCheck(r, PetscObjectComm((PetscObject)sym), PETSC_ERR_ARG_UNKNOWN_TYPE, "Unknown PetscSectionSym type: %s", method);
3332:   PetscTryTypeMethod(sym, destroy);
3333:   sym->ops->destroy = NULL;

3335:   PetscCall((*r)(sym));
3336:   PetscCall(PetscObjectChangeTypeName((PetscObject)sym, method));
3337:   PetscFunctionReturn(PETSC_SUCCESS);
3338: }

3340: /*@
3341:   PetscSectionSymGetType - Gets the section symmetry type name (as a string) from the `PetscSectionSym`.

3343:   Not Collective

3345:   Input Parameter:
3346: . sym - The section symmetry

3348:   Output Parameter:
3349: . type - The index set type name

3351:   Level: developer

3353: .seealso: [PetscSection](sec_petscsection), `PetscSectionSym`, `PetscSectionSymType`, `PetscSectionSymSetType()`, `PetscSectionSymCreate()`
3354: @*/
3355: PetscErrorCode PetscSectionSymGetType(PetscSectionSym sym, PetscSectionSymType *type)
3356: {
3357:   PetscFunctionBegin;
3359:   PetscAssertPointer(type, 2);
3360:   *type = ((PetscObject)sym)->type_name;
3361:   PetscFunctionReturn(PETSC_SUCCESS);
3362: }

3364: /*@C
3365:   PetscSectionSymRegister - Registers a new section symmetry implementation

3367:   Not Collective, No Fortran Support

3369:   Input Parameters:
3370: + sname    - The name of a new user-defined creation routine
3371: - function - The creation routine itself

3373:   Level: developer

3375:   Notes:
3376:   `PetscSectionSymRegister()` may be called multiple times to add several user-defined vectors

3378: .seealso: [PetscSection](sec_petscsection), `PetscSectionSym`, `PetscSectionSymType`, `PetscSectionSymCreate()`, `PetscSectionSymSetType()`
3379: @*/
3380: PetscErrorCode PetscSectionSymRegister(const char sname[], PetscErrorCode (*function)(PetscSectionSym))
3381: {
3382:   PetscFunctionBegin;
3383:   PetscCall(ISInitializePackage());
3384:   PetscCall(PetscFunctionListAdd(&PetscSectionSymList, sname, function));
3385:   PetscFunctionReturn(PETSC_SUCCESS);
3386: }

3388: /*@
3389:   PetscSectionSymDestroy - Destroys a section symmetry.

3391:   Collective

3393:   Input Parameter:
3394: . sym - the section symmetry

3396:   Level: developer

3398: .seealso: [PetscSection](sec_petscsection), `PetscSectionSym`, `PetscSectionSymCreate()`
3399: @*/
3400: PetscErrorCode PetscSectionSymDestroy(PetscSectionSym *sym)
3401: {
3402:   SymWorkLink link, next;

3404:   PetscFunctionBegin;
3405:   if (!*sym) PetscFunctionReturn(PETSC_SUCCESS);
3407:   if (--((PetscObject)*sym)->refct > 0) {
3408:     *sym = NULL;
3409:     PetscFunctionReturn(PETSC_SUCCESS);
3410:   }
3411:   PetscTryTypeMethod(*sym, destroy);
3412:   PetscCheck(!(*sym)->workout, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Work array still checked out");
3413:   for (link = (*sym)->workin; link; link = next) {
3414:     PetscInt    **perms = (PetscInt **)link->perms;
3415:     PetscScalar **rots  = (PetscScalar **)link->rots;
3416:     PetscCall(PetscFree2(perms, rots));
3417:     next = link->next;
3418:     PetscCall(PetscFree(link));
3419:   }
3420:   (*sym)->workin = NULL;
3421:   PetscCall(PetscHeaderDestroy(sym));
3422:   PetscFunctionReturn(PETSC_SUCCESS);
3423: }

3425: /*@
3426:   PetscSectionSymView - Displays a section symmetry

3428:   Collective

3430:   Input Parameters:
3431: + sym    - the index set
3432: - viewer - viewer used to display the set, for example `PETSC_VIEWER_STDOUT_SELF`.

3434:   Level: developer

3436: .seealso: `PetscSectionSym`, `PetscViewer`, `PetscViewerASCIIOpen()`
3437: @*/
3438: PetscErrorCode PetscSectionSymView(PetscSectionSym sym, PetscViewer viewer)
3439: {
3440:   PetscFunctionBegin;
3442:   if (!viewer) PetscCall(PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)sym), &viewer));
3444:   PetscCheckSameComm(sym, 1, viewer, 2);
3445:   PetscCall(PetscObjectPrintClassNamePrefixType((PetscObject)sym, viewer));
3446:   PetscTryTypeMethod(sym, view, viewer);
3447:   PetscFunctionReturn(PETSC_SUCCESS);
3448: }

3450: /*@
3451:   PetscSectionSetSym - Set the symmetries for the data referred to by the section

3453:   Collective

3455:   Input Parameters:
3456: + section - the section describing data layout
3457: - sym     - the symmetry describing the affect of orientation on the access of the data

3459:   Level: developer

3461: .seealso: [PetscSection](sec_petscsection), `PetscSectionSym`, `PetscSectionGetSym()`, `PetscSectionSymCreate()`
3462: @*/
3463: PetscErrorCode PetscSectionSetSym(PetscSection section, PetscSectionSym sym)
3464: {
3465:   PetscFunctionBegin;
3467:   PetscCall(PetscSectionSymDestroy(&section->sym));
3468:   if (sym) {
3470:     PetscCheckSameComm(section, 1, sym, 2);
3471:     PetscCall(PetscObjectReference((PetscObject)sym));
3472:   }
3473:   section->sym = sym;
3474:   PetscFunctionReturn(PETSC_SUCCESS);
3475: }

3477: /*@
3478:   PetscSectionGetSym - Get the symmetries for the data referred to by the section

3480:   Not Collective

3482:   Input Parameter:
3483: . section - the section describing data layout

3485:   Output Parameter:
3486: . sym - the symmetry describing the affect of orientation on the access of the data, provided previously by `PetscSectionSetSym()`

3488:   Level: developer

3490: .seealso: [PetscSection](sec_petscsection), `PetscSectionSym`, `PetscSectionSetSym()`, `PetscSectionSymCreate()`
3491: @*/
3492: PetscErrorCode PetscSectionGetSym(PetscSection section, PetscSectionSym *sym)
3493: {
3494:   PetscFunctionBegin;
3496:   *sym = section->sym;
3497:   PetscFunctionReturn(PETSC_SUCCESS);
3498: }

3500: /*@
3501:   PetscSectionSetFieldSym - Set the symmetries for the data referred to by a field of the section

3503:   Collective

3505:   Input Parameters:
3506: + section - the section describing data layout
3507: . field   - the field number
3508: - sym     - the symmetry describing the affect of orientation on the access of the data

3510:   Level: developer

3512: .seealso: [PetscSection](sec_petscsection), `PetscSectionSym`, `PetscSectionGetFieldSym()`, `PetscSectionSymCreate()`
3513: @*/
3514: PetscErrorCode PetscSectionSetFieldSym(PetscSection section, PetscInt field, PetscSectionSym sym)
3515: {
3516:   PetscFunctionBegin;
3518:   PetscSectionCheckValidField(field, section->numFields);
3519:   PetscCall(PetscSectionSetSym(section->field[field], sym));
3520:   PetscFunctionReturn(PETSC_SUCCESS);
3521: }

3523: /*@
3524:   PetscSectionGetFieldSym - Get the symmetries for the data referred to by a field of the section

3526:   Collective

3528:   Input Parameters:
3529: + section - the section describing data layout
3530: - field   - the field number

3532:   Output Parameter:
3533: . sym - the symmetry describing the affect of orientation on the access of the data

3535:   Level: developer

3537: .seealso: [PetscSection](sec_petscsection), `PetscSectionSym`, `PetscSectionSetFieldSym()`, `PetscSectionSymCreate()`
3538: @*/
3539: PetscErrorCode PetscSectionGetFieldSym(PetscSection section, PetscInt field, PetscSectionSym *sym)
3540: {
3541:   PetscFunctionBegin;
3543:   PetscSectionCheckValidField(field, section->numFields);
3544:   *sym = section->field[field]->sym;
3545:   PetscFunctionReturn(PETSC_SUCCESS);
3546: }

3548: /*@C
3549:   PetscSectionGetPointSyms - Get the symmetries for a set of points in a `PetscSection` under specific orientations.

3551:   Not Collective

3553:   Input Parameters:
3554: + section   - the section
3555: . numPoints - the number of points
3556: - points    - an array of size 2 * `numPoints`, containing a list of (point, orientation) pairs. (An orientation is an
3557:               arbitrary integer: its interpretation is up to sym.  Orientations are used by `DM`: for their interpretation in that
3558:               context, see `DMPlexGetConeOrientation()`).

3560:   Output Parameters:
3561: + perms - The permutations for the given orientations (or `NULL` if there is no symmetry or the permutation is the identity).
3562: - rots  - The field rotations symmetries for the given orientations (or `NULL` if there is no symmetry or the rotations are all
3563:     identity).

3565:   Example of usage, gathering dofs into a local array (lArray) from a section array (sArray):
3566: .vb
3567:      const PetscInt    **perms;
3568:      const PetscScalar **rots;
3569:      PetscInt            lOffset;

3571:      PetscSectionGetPointSyms(section,numPoints,points,&perms,&rots);
3572:      for (i = 0, lOffset = 0; i < numPoints; i++) {
3573:        PetscInt           point = points[2*i], dof, sOffset;
3574:        const PetscInt    *perm  = perms ? perms[i] : NULL;
3575:        const PetscScalar *rot   = rots  ? rots[i]  : NULL;

3577:        PetscSectionGetDof(section,point,&dof);
3578:        PetscSectionGetOffset(section,point,&sOffset);

3580:        if (perm) {for (j = 0; j < dof; j++) {lArray[lOffset + perm[j]]  = sArray[sOffset + j];}}
3581:        else      {for (j = 0; j < dof; j++) {lArray[lOffset +      j ]  = sArray[sOffset + j];}}
3582:        if (rot)  {for (j = 0; j < dof; j++) {lArray[lOffset +      j ] *= rot[j];             }}
3583:        lOffset += dof;
3584:      }
3585:      PetscSectionRestorePointSyms(section,numPoints,points,&perms,&rots);
3586: .ve

3588:   Example of usage, adding dofs into a section array (sArray) from a local array (lArray):
3589: .vb
3590:      const PetscInt    **perms;
3591:      const PetscScalar **rots;
3592:      PetscInt            lOffset;

3594:      PetscSectionGetPointSyms(section,numPoints,points,&perms,&rots);
3595:      for (i = 0, lOffset = 0; i < numPoints; i++) {
3596:        PetscInt           point = points[2*i], dof, sOffset;
3597:        const PetscInt    *perm  = perms ? perms[i] : NULL;
3598:        const PetscScalar *rot   = rots  ? rots[i]  : NULL;

3600:        PetscSectionGetDof(section,point,&dof);
3601:        PetscSectionGetOffset(section,point,&sOff);

3603:        if (perm) {for (j = 0; j < dof; j++) {sArray[sOffset + j] += lArray[lOffset + perm[j]] * (rot ? PetscConj(rot[perm[j]]) : 1.);}}
3604:        else      {for (j = 0; j < dof; j++) {sArray[sOffset + j] += lArray[lOffset +      j ] * (rot ? PetscConj(rot[     j ]) : 1.);}}
3605:        offset += dof;
3606:      }
3607:      PetscSectionRestorePointSyms(section,numPoints,points,&perms,&rots);
3608: .ve

3610:   Level: developer

3612:   Notes:
3613:   `PetscSectionSetSym()` must have been previously called to provide the symmetries to the `PetscSection`

3615:   Use `PetscSectionRestorePointSyms()` when finished with the data

3617: .seealso: [PetscSection](sec_petscsection), `PetscSectionSym`, `PetscSectionRestorePointSyms()`, `PetscSectionSymCreate()`, `PetscSectionSetSym()`, `PetscSectionGetSym()`
3618: @*/
3619: PetscErrorCode PetscSectionGetPointSyms(PetscSection section, PetscInt numPoints, const PetscInt *points, const PetscInt ***perms, const PetscScalar ***rots)
3620: {
3621:   PetscSectionSym sym;

3623:   PetscFunctionBegin;
3625:   if (numPoints) PetscAssertPointer(points, 3);
3626:   if (perms) *perms = NULL;
3627:   if (rots) *rots = NULL;
3628:   sym = section->sym;
3629:   if (sym && (perms || rots)) {
3630:     SymWorkLink link;

3632:     if (sym->workin) {
3633:       link        = sym->workin;
3634:       sym->workin = sym->workin->next;
3635:     } else {
3636:       PetscCall(PetscNew(&link));
3637:     }
3638:     if (numPoints > link->numPoints) {
3639:       PetscInt    **perms = (PetscInt **)link->perms;
3640:       PetscScalar **rots  = (PetscScalar **)link->rots;
3641:       PetscCall(PetscFree2(perms, rots));
3642:       PetscCall(PetscMalloc2(numPoints, (PetscInt ***)&link->perms, numPoints, (PetscScalar ***)&link->rots));
3643:       link->numPoints = numPoints;
3644:     }
3645:     link->next   = sym->workout;
3646:     sym->workout = link;
3647:     PetscCall(PetscArrayzero((PetscInt **)link->perms, numPoints));
3648:     PetscCall(PetscArrayzero((PetscInt **)link->rots, numPoints));
3649:     PetscUseTypeMethod(sym, getpoints, section, numPoints, points, link->perms, link->rots);
3650:     if (perms) *perms = link->perms;
3651:     if (rots) *rots = link->rots;
3652:   }
3653:   PetscFunctionReturn(PETSC_SUCCESS);
3654: }

3656: /*@C
3657:   PetscSectionRestorePointSyms - Restore the symmetries returned by `PetscSectionGetPointSyms()`

3659:   Not Collective

3661:   Input Parameters:
3662: + section   - the section
3663: . numPoints - the number of points
3664: . points    - an array of size 2 * `numPoints`, containing a list of (point, orientation) pairs. (An orientation is an
3665:               arbitrary integer: its interpretation is up to sym.  Orientations are used by `DM`: for their interpretation in that
3666:               context, see `DMPlexGetConeOrientation()`).
3667: . perms     - The permutations for the given orientations: set to `NULL` at conclusion
3668: - rots      - The field rotations symmetries for the given orientations: set to `NULL` at conclusion

3670:   Level: developer

3672: .seealso: [PetscSection](sec_petscsection), `PetscSectionSym`, `PetscSectionGetPointSyms()`, `PetscSectionSymCreate()`, `PetscSectionSetSym()`, `PetscSectionGetSym()`
3673: @*/
3674: PetscErrorCode PetscSectionRestorePointSyms(PetscSection section, PetscInt numPoints, const PetscInt *points, const PetscInt ***perms, const PetscScalar ***rots)
3675: {
3676:   PetscSectionSym sym;

3678:   PetscFunctionBegin;
3680:   sym = section->sym;
3681:   if (sym && (perms || rots)) {
3682:     SymWorkLink *p, link;

3684:     for (p = &sym->workout; (link = *p); p = &link->next) {
3685:       if ((perms && link->perms == *perms) || (rots && link->rots == *rots)) {
3686:         *p          = link->next;
3687:         link->next  = sym->workin;
3688:         sym->workin = link;
3689:         if (perms) *perms = NULL;
3690:         if (rots) *rots = NULL;
3691:         PetscFunctionReturn(PETSC_SUCCESS);
3692:       }
3693:     }
3694:     SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Array was not checked out");
3695:   }
3696:   PetscFunctionReturn(PETSC_SUCCESS);
3697: }

3699: /*@C
3700:   PetscSectionGetFieldPointSyms - Get the symmetries for a set of points in a field of a `PetscSection` under specific orientations.

3702:   Not Collective

3704:   Input Parameters:
3705: + section   - the section
3706: . field     - the field of the section
3707: . numPoints - the number of points
3708: - points    - an array of size 2 * `numPoints`, containing a list of (point, orientation) pairs. (An orientation is an
3709:     arbitrary integer: its interpretation is up to sym.  Orientations are used by `DM`: for their interpretation in that
3710:     context, see `DMPlexGetConeOrientation()`).

3712:   Output Parameters:
3713: + perms - The permutations for the given orientations (or `NULL` if there is no symmetry or the permutation is the identity).
3714: - rots  - The field rotations symmetries for the given orientations (or `NULL` if there is no symmetry or the rotations are all
3715:     identity).

3717:   Level: developer

3719:   Notes:
3720:   `PetscSectionSetFieldSym()` must have been previously called to provide the symmetries to the `PetscSection`

3722:   Use `PetscSectionRestoreFieldPointSyms()` when finished with the data

3724: .seealso: [PetscSection](sec_petscsection), `PetscSectionSym`, `PetscSectionGetPointSyms()`, `PetscSectionRestoreFieldPointSyms()`
3725: @*/
3726: PetscErrorCode PetscSectionGetFieldPointSyms(PetscSection section, PetscInt field, PetscInt numPoints, const PetscInt *points, const PetscInt ***perms, const PetscScalar ***rots)
3727: {
3728:   PetscFunctionBegin;
3730:   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);
3731:   PetscCall(PetscSectionGetPointSyms(section->field[field], numPoints, points, perms, rots));
3732:   PetscFunctionReturn(PETSC_SUCCESS);
3733: }

3735: /*@C
3736:   PetscSectionRestoreFieldPointSyms - Restore the symmetries returned by `PetscSectionGetFieldPointSyms()`

3738:   Not Collective

3740:   Input Parameters:
3741: + section   - the section
3742: . field     - the field number
3743: . numPoints - the number of points
3744: . points    - an array of size 2 * `numPoints`, containing a list of (point, orientation) pairs. (An orientation is an
3745:     arbitrary integer: its interpretation is up to sym.  Orientations are used by `DM`: for their interpretation in that
3746:     context, see `DMPlexGetConeOrientation()`).
3747: . perms     - The permutations for the given orientations: set to NULL at conclusion
3748: - rots      - The field rotations symmetries for the given orientations: set to NULL at conclusion

3750:   Level: developer

3752: .seealso: [PetscSection](sec_petscsection), `PetscSectionSym`, `PetscSectionRestorePointSyms()`, `petscSectionGetFieldPointSyms()`, `PetscSectionSymCreate()`, `PetscSectionSetSym()`, `PetscSectionGetSym()`
3753: @*/
3754: PetscErrorCode PetscSectionRestoreFieldPointSyms(PetscSection section, PetscInt field, PetscInt numPoints, const PetscInt *points, const PetscInt ***perms, const PetscScalar ***rots)
3755: {
3756:   PetscFunctionBegin;
3758:   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);
3759:   PetscCall(PetscSectionRestorePointSyms(section->field[field], numPoints, points, perms, rots));
3760:   PetscFunctionReturn(PETSC_SUCCESS);
3761: }

3763: /*@
3764:   PetscSectionSymCopy - Copy the symmetries, assuming that the point structure is compatible

3766:   Not Collective

3768:   Input Parameter:
3769: . sym - the `PetscSectionSym`

3771:   Output Parameter:
3772: . nsym - the equivalent symmetries

3774:   Level: developer

3776: .seealso: [PetscSection](sec_petscsection), `PetscSectionSym`, `PetscSectionSymCreate()`, `PetscSectionSetSym()`, `PetscSectionGetSym()`, `PetscSectionSymLabelSetStratum()`, `PetscSectionGetPointSyms()`
3777: @*/
3778: PetscErrorCode PetscSectionSymCopy(PetscSectionSym sym, PetscSectionSym nsym)
3779: {
3780:   PetscFunctionBegin;
3783:   PetscTryTypeMethod(sym, copy, nsym);
3784:   PetscFunctionReturn(PETSC_SUCCESS);
3785: }

3787: /*@
3788:   PetscSectionSymDistribute - Distribute the symmetries in accordance with the input `PetscSF`

3790:   Collective

3792:   Input Parameters:
3793: + sym         - the `PetscSectionSym`
3794: - migrationSF - the distribution map from roots to leaves

3796:   Output Parameter:
3797: . dsym - the redistributed symmetries

3799:   Level: developer

3801: .seealso: [PetscSection](sec_petscsection), `PetscSectionSym`, `PetscSectionSymCreate()`, `PetscSectionSetSym()`, `PetscSectionGetSym()`, `PetscSectionSymLabelSetStratum()`, `PetscSectionGetPointSyms()`
3802: @*/
3803: PetscErrorCode PetscSectionSymDistribute(PetscSectionSym sym, PetscSF migrationSF, PetscSectionSym *dsym)
3804: {
3805:   PetscFunctionBegin;
3808:   PetscAssertPointer(dsym, 3);
3809:   PetscTryTypeMethod(sym, distribute, migrationSF, dsym);
3810:   PetscFunctionReturn(PETSC_SUCCESS);
3811: }

3813: /*@
3814:   PetscSectionGetUseFieldOffsets - Get the flag indicating if field offsets are used directly in a global section, rather than just the point offset

3816:   Not Collective

3818:   Input Parameter:
3819: . s - the global `PetscSection`

3821:   Output Parameter:
3822: . flg - the flag

3824:   Level: developer

3826: .seealso: [PetscSection](sec_petscsection), `PetscSectionSym`, `PetscSectionSetChart()`, `PetscSectionCreate()`
3827: @*/
3828: PetscErrorCode PetscSectionGetUseFieldOffsets(PetscSection s, PetscBool *flg)
3829: {
3830:   PetscFunctionBegin;
3832:   *flg = s->useFieldOff;
3833:   PetscFunctionReturn(PETSC_SUCCESS);
3834: }

3836: /*@
3837:   PetscSectionSetUseFieldOffsets - Set the flag to use field offsets directly in a global section, rather than just the point offset

3839:   Not Collective

3841:   Input Parameters:
3842: + s   - the global `PetscSection`
3843: - flg - the flag

3845:   Level: developer

3847: .seealso: [PetscSection](sec_petscsection), `PetscSectionSym`, `PetscSectionGetUseFieldOffsets()`, `PetscSectionSetChart()`, `PetscSectionCreate()`
3848: @*/
3849: PetscErrorCode PetscSectionSetUseFieldOffsets(PetscSection s, PetscBool flg)
3850: {
3851:   PetscFunctionBegin;
3853:   s->useFieldOff = flg;
3854:   PetscFunctionReturn(PETSC_SUCCESS);
3855: }

3857: #define PetscSectionExpandPoints_Loop(TYPE) \
3858:   do { \
3859:     PetscInt i, n, o0, o1, size; \
3860:     TYPE    *a0 = (TYPE *)origArray, *a1; \
3861:     PetscCall(PetscSectionGetStorageSize(s, &size)); \
3862:     PetscCall(PetscMalloc1(size, &a1)); \
3863:     for (i = 0; i < npoints; i++) { \
3864:       PetscCall(PetscSectionGetOffset(origSection, points_[i], &o0)); \
3865:       PetscCall(PetscSectionGetOffset(s, i, &o1)); \
3866:       PetscCall(PetscSectionGetDof(s, i, &n)); \
3867:       PetscCall(PetscMemcpy(&a1[o1], &a0[o0], n *unitsize)); \
3868:     } \
3869:     *newArray = (void *)a1; \
3870:   } while (0)

3872: /*@
3873:   PetscSectionExtractDofsFromArray - Extracts elements of an array corresponding to DOFs of specified points.

3875:   Not Collective

3877:   Input Parameters:
3878: + origSection - the `PetscSection` describing the layout of the array
3879: . dataType    - `MPI_Datatype` describing the data type of the array (currently only `MPIU_INT`, `MPIU_SCALAR`, `MPIU_REAL`)
3880: . origArray   - the array; its size must be equal to the storage size of `origSection`
3881: - points      - `IS` with points to extract; its indices must lie in the chart of `origSection`

3883:   Output Parameters:
3884: + newSection - the new `PetscSection` describing the layout of the new array (with points renumbered 0,1,... but preserving numbers of DOFs)
3885: - newArray   - the array of the extracted DOFs; its size is the storage size of `newSection`

3887:   Level: developer

3889: .seealso: [PetscSection](sec_petscsection), `PetscSectionSym`, `PetscSectionGetChart()`, `PetscSectionGetDof()`, `PetscSectionGetStorageSize()`, `PetscSectionCreate()`
3890: @*/
3891: PetscErrorCode PetscSectionExtractDofsFromArray(PetscSection origSection, MPI_Datatype dataType, const void *origArray, IS points, PetscSection *newSection, void *newArray[])
3892: {
3893:   PetscSection    s;
3894:   const PetscInt *points_;
3895:   PetscInt        i, n, npoints, pStart, pEnd;
3896:   PetscMPIInt     unitsize;

3898:   PetscFunctionBegin;
3900:   PetscAssertPointer(origArray, 3);
3902:   if (newSection) PetscAssertPointer(newSection, 5);
3903:   if (newArray) PetscAssertPointer(newArray, 6);
3904:   PetscCallMPI(MPI_Type_size(dataType, &unitsize));
3905:   PetscCall(ISGetLocalSize(points, &npoints));
3906:   PetscCall(ISGetIndices(points, &points_));
3907:   PetscCall(PetscSectionGetChart(origSection, &pStart, &pEnd));
3908:   PetscCall(PetscSectionCreate(PETSC_COMM_SELF, &s));
3909:   PetscCall(PetscSectionSetChart(s, 0, npoints));
3910:   for (i = 0; i < npoints; i++) {
3911:     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);
3912:     PetscCall(PetscSectionGetDof(origSection, points_[i], &n));
3913:     PetscCall(PetscSectionSetDof(s, i, n));
3914:   }
3915:   PetscCall(PetscSectionSetUp(s));
3916:   if (newArray) {
3917:     if (dataType == MPIU_INT) {
3918:       PetscSectionExpandPoints_Loop(PetscInt);
3919:     } else if (dataType == MPIU_SCALAR) {
3920:       PetscSectionExpandPoints_Loop(PetscScalar);
3921:     } else if (dataType == MPIU_REAL) {
3922:       PetscSectionExpandPoints_Loop(PetscReal);
3923:     } else SETERRQ(PETSC_COMM_SELF, PETSC_ERR_SUP, "not implemented for this MPI_Datatype");
3924:   }
3925:   if (newSection) {
3926:     *newSection = s;
3927:   } else {
3928:     PetscCall(PetscSectionDestroy(&s));
3929:   }
3930:   PetscCall(ISRestoreIndices(points, &points_));
3931:   PetscFunctionReturn(PETSC_SUCCESS);
3932: }