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](ch_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](ch_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](ch_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](ch_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](ch_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:   PetscMPIInt     mflg;

257:   PetscFunctionBegin;
260:   PetscAssertPointer(congruent, 3);
261:   *congruent = PETSC_FALSE;

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

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

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

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

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

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

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

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

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

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

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

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

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

328:   *congruent = PETSC_TRUE;
329: not_congruent:
330:   PetscCallMPI(MPIU_Allreduce(MPI_IN_PLACE, congruent, 1, MPI_C_BOOL, MPI_LAND, PetscObjectComm((PetscObject)s1)));
331:   PetscFunctionReturn(PETSC_SUCCESS);
332: }

334: /*@
335:   PetscSectionGetNumFields - Returns the number of fields in a `PetscSection`, or 0 if no fields were defined.

337:   Not Collective

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

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

345:   Level: intermediate

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

358: /*@
359:   PetscSectionSetNumFields - Sets the number of fields in a `PetscSection`

361:   Not Collective

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

367:   Level: intermediate

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

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

374: .seealso: [PetscSection](ch_petscsection), `PetscSection`, `PetscSectionGetNumFields()`, `PetscSectionSetChart()`, `PetscSectionReset()`
375: @*/
376: PetscErrorCode PetscSectionSetNumFields(PetscSection s, PetscInt numFields)
377: {
378:   PetscFunctionBegin;
380:   PetscCheck(numFields > 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "The number of fields %" PetscInt_FMT " must be positive", numFields);
381:   PetscCall(PetscSectionReset(s));

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

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

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

403: /*@
404:   PetscSectionGetFieldName - Returns the name of a field in the `PetscSection`

406:   Not Collective

408:   Input Parameters:
409: + s     - the `PetscSection`
410: - field - the field number

412:   Output Parameter:
413: . fieldName - the field name

415:   Level: intermediate

417:   Note:
418:   Will error if the field number is out of range

420: .seealso: [PetscSection](ch_petscsection), `PetscSection`, `PetscSectionSetFieldName()`, `PetscSectionSetNumFields()`, `PetscSectionGetNumFields()`
421: @*/
422: PetscErrorCode PetscSectionGetFieldName(PetscSection s, PetscInt field, const char *fieldName[])
423: {
424:   PetscFunctionBegin;
426:   PetscAssertPointer(fieldName, 3);
427:   PetscSectionCheckValidField(field, s->numFields);
428:   *fieldName = s->fieldNames[field];
429:   PetscFunctionReturn(PETSC_SUCCESS);
430: }

432: /*@
433:   PetscSectionSetFieldName - Sets the name of a field in the `PetscSection`

435:   Not Collective

437:   Input Parameters:
438: + s         - the `PetscSection`
439: . field     - the field number
440: - fieldName - the field name

442:   Level: intermediate

444:   Note:
445:   Will error if the field number is out of range

447: .seealso: [PetscSection](ch_petscsection), `PetscSectionGetFieldName()`, `PetscSectionSetNumFields()`, `PetscSectionGetNumFields()`
448: @*/
449: PetscErrorCode PetscSectionSetFieldName(PetscSection s, PetscInt field, const char fieldName[])
450: {
451:   PetscFunctionBegin;
453:   if (fieldName) PetscAssertPointer(fieldName, 3);
454:   PetscSectionCheckValidField(field, s->numFields);
455:   PetscCall(PetscFree(s->fieldNames[field]));
456:   PetscCall(PetscStrallocpy(fieldName, &s->fieldNames[field]));
457:   PetscFunctionReturn(PETSC_SUCCESS);
458: }

460: /*@
461:   PetscSectionGetComponentName - Gets the name of a field component in the `PetscSection`

463:   Not Collective

465:   Input Parameters:
466: + s     - the `PetscSection`
467: . field - the field number
468: - comp  - the component number

470:   Output Parameter:
471: . compName - the component name

473:   Level: intermediate

475:   Note:
476:   Will error if the field or component number do not exist

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

481: .seealso: [PetscSection](ch_petscsection), `PetscSection`, `PetscSectionGetFieldName()`, `PetscSectionSetNumFields()`, `PetscSectionGetNumFields()`,
482:           `PetscSectionSetComponentName()`, `PetscSectionSetFieldName()`, `PetscSectionGetFieldComponents()`, `PetscSectionSetFieldComponents()`
483: @*/
484: PetscErrorCode PetscSectionGetComponentName(PetscSection s, PetscInt field, PetscInt comp, const char *compName[])
485: {
486:   PetscFunctionBegin;
488:   PetscAssertPointer(compName, 4);
489:   PetscSectionCheckValidField(field, s->numFields);
490:   PetscSectionCheckValidFieldComponent(comp, s->numFieldComponents[field]);
491:   *compName = s->compNames[field][comp];
492:   PetscFunctionReturn(PETSC_SUCCESS);
493: }

495: /*@
496:   PetscSectionSetComponentName - Sets the name of a field component in the `PetscSection`

498:   Not Collective

500:   Input Parameters:
501: + s        - the `PetscSection`
502: . field    - the field number
503: . comp     - the component number
504: - compName - the component name

506:   Level: advanced

508:   Note:
509:   Will error if the field or component number do not exist

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

514: .seealso: [PetscSection](ch_petscsection), `PetscSection`, `PetscSectionGetComponentName()`, `PetscSectionSetNumFields()`, `PetscSectionGetNumFields()`,
515:           `PetscSectionSetFieldName()`, `PetscSectionGetFieldComponents()`, `PetscSectionSetFieldComponents()`
516: @*/
517: PetscErrorCode PetscSectionSetComponentName(PetscSection s, PetscInt field, PetscInt comp, const char compName[])
518: {
519:   PetscFunctionBegin;
521:   if (compName) PetscAssertPointer(compName, 4);
522:   PetscSectionCheckValidField(field, s->numFields);
523:   PetscSectionCheckValidFieldComponent(comp, s->numFieldComponents[field]);
524:   PetscCall(PetscFree(s->compNames[field][comp]));
525:   PetscCall(PetscStrallocpy(compName, &s->compNames[field][comp]));
526:   PetscFunctionReturn(PETSC_SUCCESS);
527: }

529: /*@
530:   PetscSectionGetFieldComponents - Returns the number of field components for the given field.

532:   Not Collective

534:   Input Parameters:
535: + s     - the `PetscSection`
536: - field - the field number

538:   Output Parameter:
539: . numComp - the number of field components

541:   Level: advanced

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

546: .seealso: [PetscSection](ch_petscsection), `PetscSection`, `PetscSectionSetFieldComponents()`, `PetscSectionGetNumFields()`,
547:           `PetscSectionSetComponentName()`, `PetscSectionGetComponentName()`
548: @*/
549: PetscErrorCode PetscSectionGetFieldComponents(PetscSection s, PetscInt field, PetscInt *numComp)
550: {
551:   PetscFunctionBegin;
553:   PetscAssertPointer(numComp, 3);
554:   PetscSectionCheckValidField(field, s->numFields);
555:   *numComp = s->numFieldComponents[field];
556:   PetscFunctionReturn(PETSC_SUCCESS);
557: }

559: /*@
560:   PetscSectionSetFieldComponents - Sets the number of field components for the given field.

562:   Not Collective

564:   Input Parameters:
565: + s       - the `PetscSection`
566: . field   - the field number
567: - numComp - the number of field components

569:   Level: advanced

571:   Note:
572:   This number can be different than the values set with `PetscSectionSetFieldDof()`. It can be used to indicate the number of
573:   components in the field of the underlying physical model which may be different than the number of degrees of freedom needed
574:   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
575:   an face based model for velocity (where the velocity normal to the face is stored) there is only 1 dof for each face point.

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

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

582: .seealso: [PetscSection](ch_petscsection), `PetscSection`, `PetscSectionGetFieldComponents()`, `PetscSectionSetComponentName()`,
583:           `PetscSectionGetComponentName()`, `PetscSectionGetNumFields()`
584: @*/
585: PetscErrorCode PetscSectionSetFieldComponents(PetscSection s, PetscInt field, PetscInt numComp)
586: {
587:   PetscFunctionBegin;
589:   PetscSectionCheckValidField(field, s->numFields);
590:   if (s->compNames) {
591:     for (PetscInt c = 0; c < s->numFieldComponents[field]; ++c) PetscCall(PetscFree(s->compNames[field][c]));
592:     PetscCall(PetscFree(s->compNames[field]));
593:   }

595:   s->numFieldComponents[field] = numComp;
596:   if (numComp) {
597:     PetscCall(PetscMalloc1(numComp, &s->compNames[field]));
598:     for (PetscInt c = 0; c < numComp; ++c) {
599:       char name[64];

601:       PetscCall(PetscSNPrintf(name, 64, "%" PetscInt_FMT, c));
602:       PetscCall(PetscStrallocpy(name, &s->compNames[field][c]));
603:     }
604:   }
605:   PetscFunctionReturn(PETSC_SUCCESS);
606: }

608: /*@
609:   PetscSectionGetChart - Returns the range [`pStart`, `pEnd`) in which points (indices) lie for this `PetscSection` on this MPI process

611:   Not Collective

613:   Input Parameter:
614: . s - the `PetscSection`

616:   Output Parameters:
617: + pStart - the first point
618: - pEnd   - one past the last point

620:   Level: intermediate

622:   Note:
623:   The chart may be thought of as the bounds on the points (indices) one may use to index into numerical data that is associated with
624:   the `PetscSection` data layout.

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

637: /*@
638:   PetscSectionSetChart - Sets the range [`pStart`, `pEnd`) in which points (indices) lie for this `PetscSection` on this MPI process

640:   Not Collective

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

647:   Level: intermediate

649:   Notes:
650:   The chart may be thought of as the bounds on the points (indices) one may use to index into numerical data that is associated with
651:   the `PetscSection` data layout.

653:   The charts on different MPI processes may (and often do) overlap

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

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

659: .seealso: [PetscSection](ch_petscsection), `PetscSection`, `PetscSectionGetChart()`, `PetscSectionCreate()`, `PetscSectionSetNumFields()`
660: @*/
661: PetscErrorCode PetscSectionSetChart(PetscSection s, PetscInt pStart, PetscInt pEnd)
662: {
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 (PetscInt 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](ch_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](ch_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](ch_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](ch_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](ch_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](ch_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](ch_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](ch_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](ch_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](ch_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](ch_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) PetscCall(PetscSectionGetDof(s->bc, point, numDof));
1118:   else *numDof = 0;
1119:   PetscFunctionReturn(PETSC_SUCCESS);
1120: }

1122: /*@
1123:   PetscSectionSetConstraintDof - Set the number of constrained degrees of freedom associated with a given point.

1125:   Not Collective

1127:   Input Parameters:
1128: + s      - the `PetscSection`
1129: . point  - the point
1130: - numDof - the number of dof which are fixed by constraints

1132:   Level: intermediate

1134: .seealso: [PetscSection](ch_petscsection), `PetscSection`, `PetscSectionSetDof()`, `PetscSectionGetConstraintDof()`, `PetscSectionCreate()`
1135: @*/
1136: PetscErrorCode PetscSectionSetConstraintDof(PetscSection s, PetscInt point, PetscInt numDof)
1137: {
1138:   PetscFunctionBegin;
1140:   if (numDof) {
1141:     PetscCall(PetscSectionCheckConstraints_Private(s));
1142:     PetscCall(PetscSectionSetDof(s->bc, point, numDof));
1143:   }
1144:   PetscFunctionReturn(PETSC_SUCCESS);
1145: }

1147: /*@
1148:   PetscSectionAddConstraintDof - Increment the number of constrained degrees of freedom associated with a given point.

1150:   Not Collective

1152:   Input Parameters:
1153: + s      - the `PetscSection`
1154: . point  - the point
1155: - numDof - the number of additional dof which are fixed by constraints

1157:   Level: intermediate

1159: .seealso: [PetscSection](ch_petscsection), `PetscSection`, `PetscSectionAddDof()`, `PetscSectionGetConstraintDof()`, `PetscSectionCreate()`
1160: @*/
1161: PetscErrorCode PetscSectionAddConstraintDof(PetscSection s, PetscInt point, PetscInt numDof)
1162: {
1163:   PetscFunctionBegin;
1165:   if (numDof) {
1166:     PetscCall(PetscSectionCheckConstraints_Private(s));
1167:     PetscCall(PetscSectionAddDof(s->bc, point, numDof));
1168:   }
1169:   PetscFunctionReturn(PETSC_SUCCESS);
1170: }

1172: /*@
1173:   PetscSectionGetFieldConstraintDof - Return the number of constrained degrees of freedom associated with a given field on a point.

1175:   Not Collective

1177:   Input Parameters:
1178: + s     - the `PetscSection`
1179: . point - the point
1180: - field - the field

1182:   Output Parameter:
1183: . numDof - the number of dof which are fixed by constraints

1185:   Level: intermediate

1187: .seealso: [PetscSection](ch_petscsection), `PetscSection`, `PetscSectionGetDof()`, `PetscSectionSetFieldConstraintDof()`, `PetscSectionCreate()`
1188: @*/
1189: PetscErrorCode PetscSectionGetFieldConstraintDof(PetscSection s, PetscInt point, PetscInt field, PetscInt *numDof)
1190: {
1191:   PetscFunctionBegin;
1193:   PetscAssertPointer(numDof, 4);
1194:   PetscSectionCheckValidField(field, s->numFields);
1195:   PetscCall(PetscSectionGetConstraintDof(s->field[field], point, numDof));
1196:   PetscFunctionReturn(PETSC_SUCCESS);
1197: }

1199: /*@
1200:   PetscSectionSetFieldConstraintDof - Set the number of constrained degrees of freedom associated with a given field on a point.

1202:   Not Collective

1204:   Input Parameters:
1205: + s      - the `PetscSection`
1206: . point  - the point
1207: . field  - the field
1208: - numDof - the number of dof which are fixed by constraints

1210:   Level: intermediate

1212: .seealso: [PetscSection](ch_petscsection), `PetscSection`, `PetscSectionSetDof()`, `PetscSectionGetFieldConstraintDof()`, `PetscSectionCreate()`
1213: @*/
1214: PetscErrorCode PetscSectionSetFieldConstraintDof(PetscSection s, PetscInt point, PetscInt field, PetscInt numDof)
1215: {
1216:   PetscFunctionBegin;
1218:   PetscSectionCheckValidField(field, s->numFields);
1219:   PetscCall(PetscSectionSetConstraintDof(s->field[field], point, numDof));
1220:   PetscFunctionReturn(PETSC_SUCCESS);
1221: }

1223: /*@
1224:   PetscSectionAddFieldConstraintDof - Increment the number of constrained degrees of freedom associated with a given field on a point.

1226:   Not Collective

1228:   Input Parameters:
1229: + s      - the `PetscSection`
1230: . point  - the point
1231: . field  - the field
1232: - numDof - the number of additional dof which are fixed by constraints

1234:   Level: intermediate

1236: .seealso: [PetscSection](ch_petscsection), `PetscSection`, `PetscSectionAddDof()`, `PetscSectionGetFieldConstraintDof()`, `PetscSectionCreate()`
1237: @*/
1238: PetscErrorCode PetscSectionAddFieldConstraintDof(PetscSection s, PetscInt point, PetscInt field, PetscInt numDof)
1239: {
1240:   PetscFunctionBegin;
1242:   PetscSectionCheckValidField(field, s->numFields);
1243:   PetscCall(PetscSectionAddConstraintDof(s->field[field], point, numDof));
1244:   PetscFunctionReturn(PETSC_SUCCESS);
1245: }

1247: /*@
1248:   PetscSectionSetUpBC - Setup the subsections describing boundary conditions.

1250:   Not Collective

1252:   Input Parameter:
1253: . s - the `PetscSection`

1255:   Level: advanced

1257: .seealso: [PetscSection](ch_petscsection), `PetscSection`, `PetscSectionSetUp()`, `PetscSectionCreate()`
1258: @*/
1259: PetscErrorCode PetscSectionSetUpBC(PetscSection s)
1260: {
1261:   PetscFunctionBegin;
1263:   if (s->bc) {
1264:     const PetscInt last = (s->bc->pEnd - s->bc->pStart) - 1;

1266:     PetscCall(PetscSectionSetUp(s->bc));
1267:     if (last >= 0) PetscCall(PetscMalloc1(s->bc->atlasOff[last] + s->bc->atlasDof[last], &s->bcIndices));
1268:     else s->bcIndices = NULL;
1269:   }
1270:   PetscFunctionReturn(PETSC_SUCCESS);
1271: }

1273: /*@
1274:   PetscSectionSetUp - Calculate offsets based upon the number of degrees of freedom for each point in preparation for use of the `PetscSection`

1276:   Not Collective

1278:   Input Parameter:
1279: . s - the `PetscSection`

1281:   Level: intermediate

1283:   Notes:
1284:   If used, `PetscSectionSetPermutation()` must be called before this routine.

1286:   `PetscSectionSetPointMajor()`, cannot be called after this routine.

1288: .seealso: [PetscSection](ch_petscsection), `PetscSection`, `PetscSectionCreate()`, `PetscSectionSetPermutation()`
1289: @*/
1290: PetscErrorCode PetscSectionSetUp(PetscSection s)
1291: {
1292:   PetscInt        f;
1293:   const PetscInt *pind   = NULL;
1294:   PetscCount      offset = 0;

1296:   PetscFunctionBegin;
1298:   if (s->setup) PetscFunctionReturn(PETSC_SUCCESS);
1299:   s->setup = PETSC_TRUE;
1300:   /* Set offsets and field offsets for all points */
1301:   /*   Assume that all fields have the same chart */
1302:   PetscCheck(s->includesConstraints, PETSC_COMM_SELF, PETSC_ERR_SUP, "PetscSectionSetUp is currently unsupported for includesConstraints = PETSC_TRUE");
1303:   if (s->perm) PetscCall(ISGetIndices(s->perm, &pind));
1304:   if (s->pointMajor) {
1305:     PetscCount foff;
1306:     for (PetscInt p = 0; p < s->pEnd - s->pStart; ++p) {
1307:       const PetscInt q = pind ? pind[p] : p;

1309:       /* Set point offset */
1310:       PetscCall(PetscIntCast(offset, &s->atlasOff[q]));
1311:       offset += s->atlasDof[q];
1312:       /* Set field offset */
1313:       for (f = 0, foff = s->atlasOff[q]; f < s->numFields; ++f) {
1314:         PetscSection sf = s->field[f];

1316:         PetscCall(PetscIntCast(foff, &sf->atlasOff[q]));
1317:         foff += sf->atlasDof[q];
1318:       }
1319:     }
1320:   } else {
1321:     /* Set field offsets for all points */
1322:     for (f = 0; f < s->numFields; ++f) {
1323:       PetscSection sf = s->field[f];

1325:       for (PetscInt p = 0; p < s->pEnd - s->pStart; ++p) {
1326:         const PetscInt q = pind ? pind[p] : p;

1328:         PetscCall(PetscIntCast(offset, &sf->atlasOff[q]));
1329:         offset += sf->atlasDof[q];
1330:       }
1331:     }
1332:     /* Disable point offsets since these are unused */
1333:     for (PetscInt p = 0; p < s->pEnd - s->pStart; ++p) s->atlasOff[p] = -1;
1334:   }
1335:   if (s->perm) PetscCall(ISRestoreIndices(s->perm, &pind));
1336:   /* Setup BC sections */
1337:   PetscCall(PetscSectionSetUpBC(s));
1338:   for (f = 0; f < s->numFields; ++f) PetscCall(PetscSectionSetUpBC(s->field[f]));
1339:   PetscFunctionReturn(PETSC_SUCCESS);
1340: }

1342: /*@
1343:   PetscSectionGetMaxDof - Return the maximum number of degrees of freedom on any point in the `PetscSection`

1345:   Not Collective

1347:   Input Parameter:
1348: . s - the `PetscSection`

1350:   Output Parameter:
1351: . maxDof - the maximum dof

1353:   Level: intermediate

1355:   Notes:
1356:   The returned number is up-to-date without need for `PetscSectionSetUp()`.

1358:   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
1359:   the maximum over all points of the value returned by `PetscSectionGetDof()` on this MPI process

1361:   Developer Notes:
1362:   The returned number is calculated lazily and stashed.

1364:   A call to `PetscSectionInvalidateMaxDof_Internal()` invalidates the stashed value.

1366:   `PetscSectionInvalidateMaxDof_Internal()` is called in `PetscSectionSetDof()`, `PetscSectionAddDof()` and `PetscSectionReset()`

1368:   It should also be called every time `atlasDof` is modified directly.

1370: .seealso: [PetscSection](ch_petscsection), `PetscSection`, `PetscSectionGetDof()`, `PetscSectionSetDof()`, `PetscSectionAddDof()`, `PetscSectionCreate()`
1371: @*/
1372: PetscErrorCode PetscSectionGetMaxDof(PetscSection s, PetscInt *maxDof)
1373: {
1374:   PetscInt p;

1376:   PetscFunctionBegin;
1378:   PetscAssertPointer(maxDof, 2);
1379:   if (s->maxDof == PETSC_INT_MIN) {
1380:     s->maxDof = 0;
1381:     for (p = 0; p < s->pEnd - s->pStart; ++p) s->maxDof = PetscMax(s->maxDof, s->atlasDof[p]);
1382:   }
1383:   *maxDof = s->maxDof;
1384:   PetscFunctionReturn(PETSC_SUCCESS);
1385: }

1387: /*@
1388:   PetscSectionGetStorageSize - Return the size of an array or local `Vec` capable of holding all the degrees of freedom defined in a `PetscSection`

1390:   Not Collective

1392:   Input Parameter:
1393: . s - the `PetscSection`

1395:   Output Parameter:
1396: . size - the size of an array which can hold all the dofs

1398:   Level: intermediate

1400: .seealso: [PetscSection](ch_petscsection), `PetscSection`, `PetscSectionGetOffset()`, `PetscSectionGetConstrainedStorageSize()`, `PetscSectionCreate()`
1401: @*/
1402: PetscErrorCode PetscSectionGetStorageSize(PetscSection s, PetscInt *size)
1403: {
1404:   PetscInt64 n = 0;

1406:   PetscFunctionBegin;
1408:   PetscAssertPointer(size, 2);
1409:   for (PetscInt p = 0; p < s->pEnd - s->pStart; ++p) n += s->atlasDof[p] > 0 ? s->atlasDof[p] : 0;
1410:   PetscCall(PetscIntCast(n, size));
1411:   PetscFunctionReturn(PETSC_SUCCESS);
1412: }

1414: /*@
1415:   PetscSectionGetConstrainedStorageSize - Return the size of an array or local `Vec` capable of holding all unconstrained degrees of freedom in a `PetscSection`

1417:   Not Collective

1419:   Input Parameter:
1420: . s - the `PetscSection`

1422:   Output Parameter:
1423: . size - the size of an array which can hold all unconstrained dofs

1425:   Level: intermediate

1427: .seealso: [PetscSection](ch_petscsection), `PetscSection`, `PetscSectionGetStorageSize()`, `PetscSectionGetOffset()`, `PetscSectionCreate()`
1428: @*/
1429: PetscErrorCode PetscSectionGetConstrainedStorageSize(PetscSection s, PetscInt *size)
1430: {
1431:   PetscInt64 n = 0;

1433:   PetscFunctionBegin;
1435:   PetscAssertPointer(size, 2);
1436:   for (PetscInt p = 0; p < s->pEnd - s->pStart; ++p) {
1437:     const PetscInt cdof = s->bc ? s->bc->atlasDof[p] : 0;
1438:     n += s->atlasDof[p] > 0 ? s->atlasDof[p] - cdof : 0;
1439:   }
1440:   PetscCall(PetscIntCast(n, size));
1441:   PetscFunctionReturn(PETSC_SUCCESS);
1442: }

1444: /*@
1445:   PetscSectionCreateGlobalSection - Create a parallel section describing the global layout using
1446:   a local (sequential) `PetscSection` on each MPI process and a `PetscSF` describing the section point overlap.

1448:   Input Parameters:
1449: + s                  - The `PetscSection` for the local field layout
1450: . sf                 - The `PetscSF` describing parallel layout of the section points (leaves are unowned local points)
1451: . usePermutation     - By default this is `PETSC_TRUE`, meaning any permutation of the local section is transferred to the global section
1452: . includeConstraints - By default this is `PETSC_FALSE`, meaning that the global field vector will not possess constrained dofs
1453: - localOffsets       - If `PETSC_TRUE`, use local rather than global offsets for the points

1455:   Output Parameter:
1456: . gsection - The `PetscSection` for the global field layout

1458:   Level: intermediate

1460:   Notes:
1461:   On each MPI process `gsection` inherits the chart of the `s` on that process.

1463:   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`.
1464:   In those locations the value of size is -(size+1) and the value of the offset on the remote process is -(off+1).

1466: .seealso: [PetscSection](ch_petscsection), `PetscSection`, `PetscSectionCreate()`, `PetscSectionCreateGlobalSectionCensored()`
1467: @*/
1468: PetscErrorCode PetscSectionCreateGlobalSection(PetscSection s, PetscSF sf, PetscBool usePermutation, PetscBool includeConstraints, PetscBool localOffsets, PetscSection *gsection)
1469: {
1470:   PetscSection    gs;
1471:   const PetscInt *pind = NULL;
1472:   PetscInt       *recv = NULL, *neg = NULL;
1473:   PetscInt        pStart, pEnd, p, dof, cdof, off, globalOff = 0, nroots, nlocal, maxleaf;
1474:   PetscInt        numFields, f, numComponents;
1475:   PetscInt        foff;

1477:   PetscFunctionBegin;
1483:   PetscAssertPointer(gsection, 6);
1484:   PetscCheck(s->pointMajor, PETSC_COMM_SELF, PETSC_ERR_SUP, "No support for field major ordering");
1485:   PetscCall(PetscSectionCreate(PetscObjectComm((PetscObject)s), &gs));
1486:   PetscCall(PetscSectionGetNumFields(s, &numFields));
1487:   if (numFields > 0) PetscCall(PetscSectionSetNumFields(gs, numFields));
1488:   PetscCall(PetscSectionGetChart(s, &pStart, &pEnd));
1489:   PetscCall(PetscSectionSetChart(gs, pStart, pEnd));
1490:   gs->includesConstraints = includeConstraints;
1491:   PetscCall(PetscSFGetGraph(sf, &nroots, NULL, NULL, NULL));
1492:   nlocal = nroots; /* The local/leaf space matches global/root space */
1493:   /* Must allocate for all points visible to SF, which may be more than this section */
1494:   if (nroots >= 0) { /* nroots < 0 means that the graph has not been set, only happens in serial */
1495:     PetscCall(PetscSFGetLeafRange(sf, NULL, &maxleaf));
1496:     PetscCheck(nroots >= pEnd, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "SF roots %" PetscInt_FMT " < pEnd %" PetscInt_FMT, nroots, pEnd);
1497:     PetscCheck(maxleaf < nroots, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Max local leaf %" PetscInt_FMT " >= nroots %" PetscInt_FMT, maxleaf, nroots);
1498:     PetscCall(PetscMalloc2(nroots, &neg, nlocal, &recv));
1499:     PetscCall(PetscArrayzero(neg, nroots));
1500:   }
1501:   /* Mark all local points with negative dof */
1502:   for (p = pStart; p < pEnd; ++p) {
1503:     PetscCall(PetscSectionGetDof(s, p, &dof));
1504:     PetscCall(PetscSectionSetDof(gs, p, dof));
1505:     PetscCall(PetscSectionGetConstraintDof(s, p, &cdof));
1506:     if (!includeConstraints && cdof > 0) PetscCall(PetscSectionSetConstraintDof(gs, p, cdof));
1507:     if (neg) neg[p] = -(dof + 1);
1508:   }
1509:   PetscCall(PetscSectionSetUpBC(gs));
1510:   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]));
1511:   if (nroots >= 0) {
1512:     PetscCall(PetscArrayzero(recv, nlocal));
1513:     PetscCall(PetscSFBcastBegin(sf, MPIU_INT, neg, recv, MPI_REPLACE));
1514:     PetscCall(PetscSFBcastEnd(sf, MPIU_INT, neg, recv, MPI_REPLACE));
1515:     for (p = pStart; p < pEnd; ++p) {
1516:       if (recv[p] < 0) {
1517:         gs->atlasDof[p - pStart] = recv[p];
1518:         PetscCall(PetscSectionGetDof(s, p, &dof));
1519:         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);
1520:       }
1521:     }
1522:   }
1523:   /* Calculate new sizes, get process offset, and calculate point offsets */
1524:   if (usePermutation && s->perm) PetscCall(ISGetIndices(s->perm, &pind));
1525:   for (p = 0, off = 0; p < pEnd - pStart; ++p) {
1526:     const PetscInt q = pind ? pind[p] : p;

1528:     cdof            = (!includeConstraints && s->bc) ? s->bc->atlasDof[q] : 0;
1529:     gs->atlasOff[q] = off;
1530:     off += gs->atlasDof[q] > 0 ? gs->atlasDof[q] - cdof : 0;
1531:   }
1532:   if (!localOffsets) {
1533:     PetscCallMPI(MPI_Scan(&off, &globalOff, 1, MPIU_INT, MPI_SUM, PetscObjectComm((PetscObject)sf)));
1534:     globalOff -= off;
1535:   }
1536:   for (p = pStart, off = 0; p < pEnd; ++p) {
1537:     gs->atlasOff[p - pStart] += globalOff;
1538:     if (neg) neg[p] = -(gs->atlasOff[p - pStart] + 1);
1539:   }
1540:   if (usePermutation && s->perm) PetscCall(ISRestoreIndices(s->perm, &pind));
1541:   /* Put in negative offsets for ghost points */
1542:   if (nroots >= 0) {
1543:     PetscCall(PetscArrayzero(recv, nlocal));
1544:     PetscCall(PetscSFBcastBegin(sf, MPIU_INT, neg, recv, MPI_REPLACE));
1545:     PetscCall(PetscSFBcastEnd(sf, MPIU_INT, neg, recv, MPI_REPLACE));
1546:     for (p = pStart; p < pEnd; ++p) {
1547:       if (recv[p] < 0) gs->atlasOff[p - pStart] = recv[p];
1548:     }
1549:   }
1550:   PetscCall(PetscFree2(neg, recv));
1551:   /* Set field dofs/offsets/constraints */
1552:   for (f = 0; f < numFields; ++f) {
1553:     const char *name;

1555:     gs->field[f]->includesConstraints = includeConstraints;
1556:     PetscCall(PetscSectionGetFieldComponents(s, f, &numComponents));
1557:     PetscCall(PetscSectionSetFieldComponents(gs, f, numComponents));
1558:     PetscCall(PetscSectionGetFieldName(s, f, &name));
1559:     PetscCall(PetscSectionSetFieldName(gs, f, name));
1560:   }
1561:   for (p = pStart; p < pEnd; ++p) {
1562:     PetscCall(PetscSectionGetOffset(gs, p, &off));
1563:     for (f = 0, foff = off; f < numFields; ++f) {
1564:       PetscCall(PetscSectionGetFieldConstraintDof(s, p, f, &cdof));
1565:       if (!includeConstraints && cdof > 0) PetscCall(PetscSectionSetFieldConstraintDof(gs, p, f, cdof));
1566:       PetscCall(PetscSectionGetFieldDof(s, p, f, &dof));
1567:       PetscCall(PetscSectionSetFieldDof(gs, p, f, off < 0 ? -(dof + 1) : dof));
1568:       PetscCall(PetscSectionSetFieldOffset(gs, p, f, foff));
1569:       PetscCall(PetscSectionGetFieldConstraintDof(gs, p, f, &cdof));
1570:       foff = off < 0 ? foff - (dof - cdof) : foff + (dof - cdof);
1571:     }
1572:   }
1573:   for (f = 0; f < numFields; ++f) {
1574:     PetscSection gfs = gs->field[f];

1576:     PetscCall(PetscSectionSetUpBC(gfs));
1577:     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]));
1578:   }
1579:   gs->setup = PETSC_TRUE;
1580:   PetscCall(PetscSectionViewFromOptions(gs, NULL, "-global_section_view"));
1581:   *gsection = gs;
1582:   PetscFunctionReturn(PETSC_SUCCESS);
1583: }

1585: /*@
1586:   PetscSectionCreateGlobalSectionCensored - Create a `PetscSection` describing the globallayout using
1587:   a local (sequential) `PetscSection` on each MPI process and an `PetscSF` describing the section point overlap.

1589:   Input Parameters:
1590: + s                  - The `PetscSection` for the local field layout
1591: . sf                 - The `PetscSF` describing parallel layout of the section points
1592: . includeConstraints - By default this is `PETSC_FALSE`, meaning that the global vector will not possess constrained dofs
1593: . numExcludes        - The number of exclusion ranges, this must have the same value on all MPI processes
1594: - 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

1596:   Output Parameter:
1597: . gsection - The `PetscSection` for the global field layout

1599:   Level: advanced

1601:   Notes:
1602:   On each MPI process `gsection` inherits the chart of the `s` on that process.

1604:   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`.
1605:   In those locations the value of size is -(size+1) and the value of the offset on the remote process is -(off+1).

1607:   This routine augments `PetscSectionCreateGlobalSection()` by allowing one to exclude certain ranges in the chart of the `PetscSection`

1609:   Developer Notes:
1610:   This is a terrible function name

1612: .seealso: [PetscSection](ch_petscsection), `PetscSection`, `PetscSectionCreate()`
1613: @*/
1614: PetscErrorCode PetscSectionCreateGlobalSectionCensored(PetscSection s, PetscSF sf, PetscBool includeConstraints, PetscInt numExcludes, const PetscInt excludes[], PetscSection *gsection)
1615: {
1616:   const PetscInt *pind = NULL;
1617:   PetscInt       *neg = NULL, *tmpOff = NULL;
1618:   PetscInt        pStart, pEnd, p, e, dof, cdof, globalOff = 0, nroots;
1619:   PetscInt        off;

1621:   PetscFunctionBegin;
1624:   PetscAssertPointer(gsection, 6);
1625:   PetscCall(PetscSectionCreate(PetscObjectComm((PetscObject)s), gsection));
1626:   PetscCall(PetscSectionGetChart(s, &pStart, &pEnd));
1627:   PetscCall(PetscSectionSetChart(*gsection, pStart, pEnd));
1628:   PetscCall(PetscSFGetGraph(sf, &nroots, NULL, NULL, NULL));
1629:   if (nroots >= 0) {
1630:     PetscCheck(nroots >= pEnd - pStart, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "PetscSF nroots %" PetscInt_FMT " < %" PetscInt_FMT " section size", nroots, pEnd - pStart);
1631:     PetscCall(PetscCalloc1(nroots, &neg));
1632:     if (nroots > pEnd - pStart) {
1633:       PetscCall(PetscCalloc1(nroots, &tmpOff));
1634:     } else {
1635:       tmpOff = &(*gsection)->atlasDof[-pStart];
1636:     }
1637:   }
1638:   /* Mark ghost points with negative dof */
1639:   for (p = pStart; p < pEnd; ++p) {
1640:     for (e = 0; e < numExcludes; ++e) {
1641:       if ((p >= excludes[e * 2 + 0]) && (p < excludes[e * 2 + 1])) {
1642:         PetscCall(PetscSectionSetDof(*gsection, p, 0));
1643:         break;
1644:       }
1645:     }
1646:     if (e < numExcludes) continue;
1647:     PetscCall(PetscSectionGetDof(s, p, &dof));
1648:     PetscCall(PetscSectionSetDof(*gsection, p, dof));
1649:     PetscCall(PetscSectionGetConstraintDof(s, p, &cdof));
1650:     if (!includeConstraints && cdof > 0) PetscCall(PetscSectionSetConstraintDof(*gsection, p, cdof));
1651:     if (neg) neg[p] = -(dof + 1);
1652:   }
1653:   PetscCall(PetscSectionSetUpBC(*gsection));
1654:   if (nroots >= 0) {
1655:     PetscCall(PetscSFBcastBegin(sf, MPIU_INT, neg, tmpOff, MPI_REPLACE));
1656:     PetscCall(PetscSFBcastEnd(sf, MPIU_INT, neg, tmpOff, MPI_REPLACE));
1657:     if (nroots > pEnd - pStart) {
1658:       for (p = pStart; p < pEnd; ++p) {
1659:         if (tmpOff[p] < 0) (*gsection)->atlasDof[p - pStart] = tmpOff[p];
1660:       }
1661:     }
1662:   }
1663:   /* Calculate new sizes, get process offset, and calculate point offsets */
1664:   if (s->perm) PetscCall(ISGetIndices(s->perm, &pind));
1665:   for (p = 0, off = 0; p < pEnd - pStart; ++p) {
1666:     const PetscInt q = pind ? pind[p] : p;

1668:     cdof                     = (!includeConstraints && s->bc) ? s->bc->atlasDof[q] : 0;
1669:     (*gsection)->atlasOff[q] = off;
1670:     off += (*gsection)->atlasDof[q] > 0 ? (*gsection)->atlasDof[q] - cdof : 0;
1671:   }
1672:   PetscCallMPI(MPI_Scan(&off, &globalOff, 1, MPIU_INT, MPI_SUM, PetscObjectComm((PetscObject)s)));
1673:   globalOff -= off;
1674:   for (p = 0, off = 0; p < pEnd - pStart; ++p) {
1675:     (*gsection)->atlasOff[p] += globalOff;
1676:     if (neg) neg[p + pStart] = -((*gsection)->atlasOff[p] + 1);
1677:   }
1678:   if (s->perm) PetscCall(ISRestoreIndices(s->perm, &pind));
1679:   /* Put in negative offsets for ghost points */
1680:   if (nroots >= 0) {
1681:     if (nroots == pEnd - pStart) tmpOff = &(*gsection)->atlasOff[-pStart];
1682:     PetscCall(PetscSFBcastBegin(sf, MPIU_INT, neg, tmpOff, MPI_REPLACE));
1683:     PetscCall(PetscSFBcastEnd(sf, MPIU_INT, neg, tmpOff, MPI_REPLACE));
1684:     if (nroots > pEnd - pStart) {
1685:       for (p = pStart; p < pEnd; ++p) {
1686:         if (tmpOff[p] < 0) (*gsection)->atlasOff[p - pStart] = tmpOff[p];
1687:       }
1688:     }
1689:   }
1690:   if (nroots >= 0 && nroots > pEnd - pStart) PetscCall(PetscFree(tmpOff));
1691:   PetscCall(PetscFree(neg));
1692:   PetscFunctionReturn(PETSC_SUCCESS);
1693: }

1695: /*@
1696:   PetscSectionGetPointLayout - Get a `PetscLayout` for the points with nonzero dof counts of the unnamed default field within this `PetscSection`s local chart

1698:   Collective

1700:   Input Parameters:
1701: + comm - The `MPI_Comm`
1702: - s    - The `PetscSection`

1704:   Output Parameter:
1705: . layout - The point layout for the data that defines the section

1707:   Level: advanced

1709:   Notes:
1710:   `PetscSectionGetValueLayout()` provides similar information but counting the total number of degrees of freedom on the MPI process (excluding constrained
1711:   degrees of freedom).

1713:   This count includes constrained degrees of freedom

1715:   This is usually called on the default global section.

1717:   Example:
1718: .vb
1719:      The chart is [2,5), point 2 has 2 dof, point 3 has 0 dof, point 4 has 1 dof
1720:      The local size of the `PetscLayout` is 2 since 2 points have a non-zero number of dof
1721: .ve

1723:   Developer Notes:
1724:   I find the names of these two functions extremely non-informative

1726: .seealso: [PetscSection](ch_petscsection), `PetscSection`, `PetscSectionGetValueLayout()`, `PetscSectionCreate()`
1727: @*/
1728: PetscErrorCode PetscSectionGetPointLayout(MPI_Comm comm, PetscSection s, PetscLayout *layout)
1729: {
1730:   PetscInt pStart, pEnd, p, localSize = 0;

1732:   PetscFunctionBegin;
1733:   PetscCall(PetscSectionGetChart(s, &pStart, &pEnd));
1734:   for (p = pStart; p < pEnd; ++p) {
1735:     PetscInt dof;

1737:     PetscCall(PetscSectionGetDof(s, p, &dof));
1738:     if (dof >= 0) ++localSize;
1739:   }
1740:   PetscCall(PetscLayoutCreate(comm, layout));
1741:   PetscCall(PetscLayoutSetLocalSize(*layout, localSize));
1742:   PetscCall(PetscLayoutSetBlockSize(*layout, 1));
1743:   PetscCall(PetscLayoutSetUp(*layout));
1744:   PetscFunctionReturn(PETSC_SUCCESS);
1745: }

1747: /*@
1748:   PetscSectionGetValueLayout - Get the `PetscLayout` associated with the section dofs of a `PetscSection`

1750:   Collective

1752:   Input Parameters:
1753: + comm - The `MPI_Comm`
1754: - s    - The `PetscSection`

1756:   Output Parameter:
1757: . layout - The dof layout for the section

1759:   Level: advanced

1761:   Notes:
1762:   `PetscSectionGetPointLayout()` provides similar information but only counting the number of points with nonzero degrees of freedom and
1763:   including the constrained degrees of freedom

1765:   This is usually called for the default global section.

1767:   Example:
1768: .vb
1769:      The chart is [2,5), point 2 has 4 dof (2 constrained), point 3 has 0 dof, point 4 has 1 dof (not constrained)
1770:      The local size of the `PetscLayout` is 3 since there are 3 unconstrained degrees of freedom on this MPI process
1771: .ve

1773: .seealso: [PetscSection](ch_petscsection), `PetscSection`, `PetscSectionGetPointLayout()`, `PetscSectionCreate()`
1774: @*/
1775: PetscErrorCode PetscSectionGetValueLayout(MPI_Comm comm, PetscSection s, PetscLayout *layout)
1776: {
1777:   PetscInt pStart, pEnd, p, localSize = 0;

1779:   PetscFunctionBegin;
1781:   PetscAssertPointer(layout, 3);
1782:   PetscCall(PetscSectionGetChart(s, &pStart, &pEnd));
1783:   for (p = pStart; p < pEnd; ++p) {
1784:     PetscInt dof, cdof;

1786:     PetscCall(PetscSectionGetDof(s, p, &dof));
1787:     PetscCall(PetscSectionGetConstraintDof(s, p, &cdof));
1788:     if (dof - cdof > 0) localSize += dof - cdof;
1789:   }
1790:   PetscCall(PetscLayoutCreate(comm, layout));
1791:   PetscCall(PetscLayoutSetLocalSize(*layout, localSize));
1792:   PetscCall(PetscLayoutSetBlockSize(*layout, 1));
1793:   PetscCall(PetscLayoutSetUp(*layout));
1794:   PetscFunctionReturn(PETSC_SUCCESS);
1795: }

1797: /*@
1798:   PetscSectionGetOffset - Return the offset into an array or `Vec` for the dof associated with the given point.

1800:   Not Collective

1802:   Input Parameters:
1803: + s     - the `PetscSection`
1804: - point - the point

1806:   Output Parameter:
1807: . offset - the offset

1809:   Level: intermediate

1811:   Notes:
1812:   In a global section, `offset` will be negative for points not owned by this process.

1814:   This is for the unnamed default field in the `PetscSection` not the named fields

1816:   The `offset` values are different depending on a value set with `PetscSectionSetPointMajor()`

1818: .seealso: [PetscSection](ch_petscsection), `PetscSection`, `PetscSectionGetFieldOffset()`, `PetscSectionCreate()`, `PetscSectionSetPointMajor()`
1819: @*/
1820: PetscErrorCode PetscSectionGetOffset(PetscSection s, PetscInt point, PetscInt *offset)
1821: {
1822:   PetscFunctionBegin;
1824:   PetscAssertPointer(offset, 3);
1825:   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);
1826:   *offset = s->atlasOff[point - s->pStart];
1827:   PetscFunctionReturn(PETSC_SUCCESS);
1828: }

1830: /*@
1831:   PetscSectionSetOffset - Set the offset into an array or `Vec` for the dof associated with the given point.

1833:   Not Collective

1835:   Input Parameters:
1836: + s      - the `PetscSection`
1837: . point  - the point
1838: - offset - the offset, these values may be negative indicating the values are off process

1840:   Level: developer

1842:   Note:
1843:   The user usually does not call this function, but uses `PetscSectionSetUp()`

1845: .seealso: [PetscSection](ch_petscsection), `PetscSection`, `PetscSectionGetFieldOffset()`, `PetscSectionCreate()`, `PetscSectionSetUp()`
1846: @*/
1847: PetscErrorCode PetscSectionSetOffset(PetscSection s, PetscInt point, PetscInt offset)
1848: {
1849:   PetscFunctionBegin;
1851:   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);
1852:   s->atlasOff[point - s->pStart] = offset;
1853:   PetscFunctionReturn(PETSC_SUCCESS);
1854: }

1856: /*@
1857:   PetscSectionGetFieldOffset - Return the offset into an array or `Vec` for the field dof associated with the given point.

1859:   Not Collective

1861:   Input Parameters:
1862: + s     - the `PetscSection`
1863: . point - the point
1864: - field - the field

1866:   Output Parameter:
1867: . offset - the offset

1869:   Level: intermediate

1871:   Notes:
1872:   In a global section, `offset` will be negative for points not owned by this process.

1874:   The `offset` values are different depending on a value set with `PetscSectionSetPointMajor()`

1876: .seealso: [PetscSection](ch_petscsection), `PetscSection`, `PetscSectionGetOffset()`, `PetscSectionCreate()`, `PetscSectionGetFieldPointOffset()`
1877: @*/
1878: PetscErrorCode PetscSectionGetFieldOffset(PetscSection s, PetscInt point, PetscInt field, PetscInt *offset)
1879: {
1880:   PetscFunctionBegin;
1882:   PetscAssertPointer(offset, 4);
1883:   PetscSectionCheckValidField(field, s->numFields);
1884:   PetscCall(PetscSectionGetOffset(s->field[field], point, offset));
1885:   PetscFunctionReturn(PETSC_SUCCESS);
1886: }

1888: /*@
1889:   PetscSectionSetFieldOffset - Set the offset into an array or `Vec` for the dof associated with the given field at a point.

1891:   Not Collective

1893:   Input Parameters:
1894: + s      - the `PetscSection`
1895: . point  - the point
1896: . field  - the field
1897: - offset - the offset, these values may be negative indicating the values are off process

1899:   Level: developer

1901:   Note:
1902:   The user usually does not call this function, but uses `PetscSectionSetUp()`

1904: .seealso: [PetscSection](ch_petscsection), `PetscSection`, `PetscSectionGetFieldOffset()`, `PetscSectionSetOffset()`, `PetscSectionCreate()`, `PetscSectionSetUp()`
1905: @*/
1906: PetscErrorCode PetscSectionSetFieldOffset(PetscSection s, PetscInt point, PetscInt field, PetscInt offset)
1907: {
1908:   PetscFunctionBegin;
1910:   PetscSectionCheckValidField(field, s->numFields);
1911:   PetscCall(PetscSectionSetOffset(s->field[field], point, offset));
1912:   PetscFunctionReturn(PETSC_SUCCESS);
1913: }

1915: /*@
1916:   PetscSectionGetFieldPointOffset - Return the offset for the first field dof associated with the given point relative to the offset for that point for the
1917:   unnamed default field's first dof

1919:   Not Collective

1921:   Input Parameters:
1922: + s     - the `PetscSection`
1923: . point - the point
1924: - field - the field

1926:   Output Parameter:
1927: . offset - the offset

1929:   Level: advanced

1931:   Note:
1932:   This ignores constraints

1934:   Example:
1935: .vb
1936:   if PetscSectionSetPointMajor(s,PETSC_TRUE)
1937:   The unnamed default field has 3 dof at `point`
1938:   Field 0 has 2 dof at `point`
1939:   Then PetscSectionGetFieldPointOffset(s,point,1,&offset) returns and offset of 5
1940: .ve

1942: .seealso: [PetscSection](ch_petscsection), `PetscSection`, `PetscSectionGetOffset()`, `PetscSectionCreate()`, `PetscSectionGetFieldOffset()`
1943: @*/
1944: PetscErrorCode PetscSectionGetFieldPointOffset(PetscSection s, PetscInt point, PetscInt field, PetscInt *offset)
1945: {
1946:   PetscInt off, foff;

1948:   PetscFunctionBegin;
1950:   PetscAssertPointer(offset, 4);
1951:   PetscSectionCheckValidField(field, s->numFields);
1952:   PetscCall(PetscSectionGetOffset(s, point, &off));
1953:   PetscCall(PetscSectionGetOffset(s->field[field], point, &foff));
1954:   *offset = foff - off;
1955:   PetscFunctionReturn(PETSC_SUCCESS);
1956: }

1958: /*@
1959:   PetscSectionGetOffsetRange - Return the full range of offsets [`start`, `end`) for a `PetscSection`

1961:   Not Collective

1963:   Input Parameter:
1964: . s - the `PetscSection`

1966:   Output Parameters:
1967: + start - the minimum offset
1968: - end   - one more than the maximum offset

1970:   Level: intermediate

1972: .seealso: [PetscSection](ch_petscsection), `PetscSection`, `PetscSectionGetOffset()`, `PetscSectionCreate()`
1973: @*/
1974: PetscErrorCode PetscSectionGetOffsetRange(PetscSection s, PetscInt *start, PetscInt *end)
1975: {
1976:   PetscInt os = 0, oe = 0, pStart, pEnd, p;

1978:   PetscFunctionBegin;
1980:   if (s->atlasOff) {
1981:     os = s->atlasOff[0];
1982:     oe = s->atlasOff[0];
1983:   }
1984:   PetscCall(PetscSectionGetChart(s, &pStart, &pEnd));
1985:   for (p = 0; p < pEnd - pStart; ++p) {
1986:     PetscInt dof = s->atlasDof[p], off = s->atlasOff[p];

1988:     if (off >= 0) {
1989:       os = PetscMin(os, off);
1990:       oe = PetscMax(oe, off + dof);
1991:     }
1992:   }
1993:   if (start) *start = os;
1994:   if (end) *end = oe;
1995:   PetscFunctionReturn(PETSC_SUCCESS);
1996: }

1998: /*@
1999:   PetscSectionCreateSubsection - Create a new, smaller `PetscSection` composed of only selected fields

2001:   Collective

2003:   Input Parameters:
2004: + s      - the `PetscSection`
2005: . len    - the number of subfields
2006: - fields - the subfield numbers

2008:   Output Parameter:
2009: . subs - the subsection

2011:   Level: advanced

2013:   Notes:
2014:   The chart of `subs` is the same as the chart of `s`

2016:   This will error if a fieldnumber is out of range

2018: .seealso: [PetscSection](ch_petscsection), `PetscSection`, `PetscSectionCreateSupersection()`, `PetscSectionCreate()`
2019: @*/
2020: PetscErrorCode PetscSectionCreateSubsection(PetscSection s, PetscInt len, const PetscInt fields[], PetscSection *subs)
2021: {
2022:   PetscInt nF, f, c, pStart, pEnd, p, maxCdof = 0;

2024:   PetscFunctionBegin;
2025:   if (!len) PetscFunctionReturn(PETSC_SUCCESS);
2027:   PetscAssertPointer(fields, 3);
2028:   PetscAssertPointer(subs, 4);
2029:   PetscCall(PetscSectionGetNumFields(s, &nF));
2030:   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);
2031:   PetscCall(PetscSectionCreate(PetscObjectComm((PetscObject)s), subs));
2032:   PetscCall(PetscSectionSetNumFields(*subs, len));
2033:   for (f = 0; f < len; ++f) {
2034:     const char     *name    = NULL;
2035:     PetscInt        numComp = 0;
2036:     PetscSectionSym sym;

2038:     PetscCall(PetscSectionGetFieldName(s, fields[f], &name));
2039:     PetscCall(PetscSectionSetFieldName(*subs, f, name));
2040:     PetscCall(PetscSectionGetFieldComponents(s, fields[f], &numComp));
2041:     PetscCall(PetscSectionSetFieldComponents(*subs, f, numComp));
2042:     for (c = 0; c < s->numFieldComponents[fields[f]]; ++c) {
2043:       PetscCall(PetscSectionGetComponentName(s, fields[f], c, &name));
2044:       PetscCall(PetscSectionSetComponentName(*subs, f, c, name));
2045:     }
2046:     PetscCall(PetscSectionGetFieldSym(s, fields[f], &sym));
2047:     PetscCall(PetscSectionSetFieldSym(*subs, f, sym));
2048:   }
2049:   PetscCall(PetscSectionGetChart(s, &pStart, &pEnd));
2050:   PetscCall(PetscSectionSetChart(*subs, pStart, pEnd));
2051:   for (p = pStart; p < pEnd; ++p) {
2052:     PetscInt dof = 0, cdof = 0, fdof = 0, cfdof = 0;

2054:     for (f = 0; f < len; ++f) {
2055:       PetscCall(PetscSectionGetFieldDof(s, p, fields[f], &fdof));
2056:       PetscCall(PetscSectionSetFieldDof(*subs, p, f, fdof));
2057:       PetscCall(PetscSectionGetFieldConstraintDof(s, p, fields[f], &cfdof));
2058:       if (cfdof) PetscCall(PetscSectionSetFieldConstraintDof(*subs, p, f, cfdof));
2059:       dof += fdof;
2060:       cdof += cfdof;
2061:     }
2062:     PetscCall(PetscSectionSetDof(*subs, p, dof));
2063:     if (cdof) PetscCall(PetscSectionSetConstraintDof(*subs, p, cdof));
2064:     maxCdof = PetscMax(cdof, maxCdof);
2065:   }
2066:   PetscBT bst, subbst;

2068:   PetscCall(PetscSectionGetBlockStarts(s, &bst));
2069:   if (bst) {
2070:     PetscCall(PetscBTCreate(pEnd - pStart, &subbst));
2071:     PetscCall(PetscBTCopy(subbst, pEnd - pStart, bst));
2072:     PetscCall(PetscSectionSetBlockStarts(*subs, subbst));
2073:   }
2074:   PetscCall(PetscSectionSetUp(*subs));
2075:   if (maxCdof) {
2076:     PetscInt *indices;

2078:     PetscCall(PetscMalloc1(maxCdof, &indices));
2079:     for (p = pStart; p < pEnd; ++p) {
2080:       PetscInt cdof;

2082:       PetscCall(PetscSectionGetConstraintDof(*subs, p, &cdof));
2083:       if (cdof) {
2084:         const PetscInt *oldIndices = NULL;
2085:         PetscInt        fdof = 0, cfdof = 0, fc, numConst = 0, fOff = 0;

2087:         for (f = 0; f < len; ++f) {
2088:           PetscCall(PetscSectionGetFieldDof(s, p, fields[f], &fdof));
2089:           PetscCall(PetscSectionGetFieldConstraintDof(s, p, fields[f], &cfdof));
2090:           PetscCall(PetscSectionGetFieldConstraintIndices(s, p, fields[f], &oldIndices));
2091:           PetscCall(PetscSectionSetFieldConstraintIndices(*subs, p, f, oldIndices));
2092:           for (fc = 0; fc < cfdof; ++fc) indices[numConst + fc] = oldIndices[fc] + fOff;
2093:           numConst += cfdof;
2094:           fOff += fdof;
2095:         }
2096:         PetscCall(PetscSectionSetConstraintIndices(*subs, p, indices));
2097:       }
2098:     }
2099:     PetscCall(PetscFree(indices));
2100:   }
2101:   PetscFunctionReturn(PETSC_SUCCESS);
2102: }

2104: /*@
2105:   PetscSectionCreateComponentSubsection - Create a new, smaller `PetscSection` composed of only selected components

2107:   Collective

2109:   Input Parameters:
2110: + s     - the `PetscSection`
2111: . len   - the number of components
2112: - comps - the component numbers

2114:   Output Parameter:
2115: . subs - the subsection

2117:   Level: advanced

2119:   Notes:
2120:   The chart of `subs` is the same as the chart of `s`

2122:   This will error if the section has more than one field, or if a component number is out of range

2124: .seealso: [PetscSection](ch_petscsection), `PetscSection`, `PetscSectionCreateSupersection()`, `PetscSectionCreate()`
2125: @*/
2126: PetscErrorCode PetscSectionCreateComponentSubsection(PetscSection s, PetscInt len, const PetscInt comps[], PetscSection *subs)
2127: {
2128:   PetscSectionSym sym;
2129:   const char     *name = NULL;
2130:   PetscInt        Nf, pStart, pEnd;

2132:   PetscFunctionBegin;
2133:   if (!len) PetscFunctionReturn(PETSC_SUCCESS);
2135:   PetscAssertPointer(comps, 3);
2136:   PetscAssertPointer(subs, 4);
2137:   PetscCall(PetscSectionGetNumFields(s, &Nf));
2138:   PetscCheck(Nf == 1, PetscObjectComm((PetscObject)s), PETSC_ERR_ARG_WRONG, "This method can only handle one field, not %" PetscInt_FMT, Nf);
2139:   PetscCall(PetscSectionCreate(PetscObjectComm((PetscObject)s), subs));
2140:   PetscCall(PetscSectionSetNumFields(*subs, 1));
2141:   PetscCall(PetscSectionGetFieldName(s, 0, &name));
2142:   PetscCall(PetscSectionSetFieldName(*subs, 0, name));
2143:   PetscCall(PetscSectionSetFieldComponents(*subs, 0, len));
2144:   PetscCall(PetscSectionGetFieldSym(s, 0, &sym));
2145:   PetscCall(PetscSectionSetFieldSym(*subs, 0, sym));
2146:   for (PetscInt c = 0; c < len; ++c) {
2147:     PetscCall(PetscSectionGetComponentName(s, 0, comps[c], &name));
2148:     PetscCall(PetscSectionSetComponentName(*subs, 0, c, name));
2149:   }
2150:   PetscCall(PetscSectionGetChart(s, &pStart, &pEnd));
2151:   PetscCall(PetscSectionSetChart(*subs, pStart, pEnd));
2152:   for (PetscInt p = pStart; p < pEnd; ++p) {
2153:     PetscInt dof, cdof, cfdof;

2155:     PetscCall(PetscSectionGetDof(s, p, &dof));
2156:     if (!dof) continue;
2157:     PetscCall(PetscSectionGetFieldConstraintDof(s, p, 0, &cfdof));
2158:     PetscCall(PetscSectionGetConstraintDof(s, p, &cdof));
2159:     PetscCheck(!cdof && !cfdof, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Component selection does not work with constraints");
2160:     PetscCall(PetscSectionSetFieldDof(*subs, p, 0, len));
2161:     PetscCall(PetscSectionSetDof(*subs, p, len));
2162:   }
2163:   PetscCall(PetscSectionSetUp(*subs));
2164:   PetscFunctionReturn(PETSC_SUCCESS);
2165: }

2167: /*@
2168:   PetscSectionCreateSupersection - Create a new, larger section composed of multiple `PetscSection`s

2170:   Collective

2172:   Input Parameters:
2173: + s   - the input sections
2174: - len - the number of input sections

2176:   Output Parameter:
2177: . supers - the supersection

2179:   Level: advanced

2181:   Notes:
2182:   The section offsets now refer to a new, larger vector.

2184:   Developer Notes:
2185:   Needs to explain how the sections are composed

2187: .seealso: [PetscSection](ch_petscsection), `PetscSection`, `PetscSectionCreateSubsection()`, `PetscSectionCreate()`
2188: @*/
2189: PetscErrorCode PetscSectionCreateSupersection(PetscSection s[], PetscInt len, PetscSection *supers)
2190: {
2191:   PetscInt Nf = 0, f, pStart = PETSC_INT_MAX, pEnd = 0, p, maxCdof = 0, i;

2193:   PetscFunctionBegin;
2194:   if (!len) PetscFunctionReturn(PETSC_SUCCESS);
2195:   for (i = 0; i < len; ++i) {
2196:     PetscInt nf, pStarti, pEndi;

2198:     PetscCall(PetscSectionGetNumFields(s[i], &nf));
2199:     PetscCall(PetscSectionGetChart(s[i], &pStarti, &pEndi));
2200:     pStart = PetscMin(pStart, pStarti);
2201:     pEnd   = PetscMax(pEnd, pEndi);
2202:     Nf += nf;
2203:   }
2204:   PetscCall(PetscSectionCreate(PetscObjectComm((PetscObject)s[0]), supers));
2205:   PetscCall(PetscSectionSetNumFields(*supers, Nf));
2206:   for (i = 0, f = 0; i < len; ++i) {
2207:     PetscInt nf, fi, ci;

2209:     PetscCall(PetscSectionGetNumFields(s[i], &nf));
2210:     for (fi = 0; fi < nf; ++fi, ++f) {
2211:       const char *name    = NULL;
2212:       PetscInt    numComp = 0;

2214:       PetscCall(PetscSectionGetFieldName(s[i], fi, &name));
2215:       PetscCall(PetscSectionSetFieldName(*supers, f, name));
2216:       PetscCall(PetscSectionGetFieldComponents(s[i], fi, &numComp));
2217:       PetscCall(PetscSectionSetFieldComponents(*supers, f, numComp));
2218:       for (ci = 0; ci < s[i]->numFieldComponents[fi]; ++ci) {
2219:         PetscCall(PetscSectionGetComponentName(s[i], fi, ci, &name));
2220:         PetscCall(PetscSectionSetComponentName(*supers, f, ci, name));
2221:       }
2222:     }
2223:   }
2224:   PetscCall(PetscSectionSetChart(*supers, pStart, pEnd));
2225:   for (p = pStart; p < pEnd; ++p) {
2226:     PetscInt dof = 0, cdof = 0;

2228:     for (i = 0, f = 0; i < len; ++i) {
2229:       PetscInt nf, fi, pStarti, pEndi;
2230:       PetscInt fdof = 0, cfdof = 0;

2232:       PetscCall(PetscSectionGetNumFields(s[i], &nf));
2233:       PetscCall(PetscSectionGetChart(s[i], &pStarti, &pEndi));
2234:       if ((p < pStarti) || (p >= pEndi)) continue;
2235:       for (fi = 0; fi < nf; ++fi, ++f) {
2236:         PetscCall(PetscSectionGetFieldDof(s[i], p, fi, &fdof));
2237:         PetscCall(PetscSectionAddFieldDof(*supers, p, f, fdof));
2238:         PetscCall(PetscSectionGetFieldConstraintDof(s[i], p, fi, &cfdof));
2239:         if (cfdof) PetscCall(PetscSectionAddFieldConstraintDof(*supers, p, f, cfdof));
2240:         dof += fdof;
2241:         cdof += cfdof;
2242:       }
2243:     }
2244:     PetscCall(PetscSectionSetDof(*supers, p, dof));
2245:     if (cdof) PetscCall(PetscSectionSetConstraintDof(*supers, p, cdof));
2246:     maxCdof = PetscMax(cdof, maxCdof);
2247:   }
2248:   PetscCall(PetscSectionSetUp(*supers));
2249:   if (maxCdof) {
2250:     PetscInt *indices;

2252:     PetscCall(PetscMalloc1(maxCdof, &indices));
2253:     for (p = pStart; p < pEnd; ++p) {
2254:       PetscInt cdof;

2256:       PetscCall(PetscSectionGetConstraintDof(*supers, p, &cdof));
2257:       if (cdof) {
2258:         PetscInt dof, numConst = 0, fOff = 0;

2260:         for (i = 0, f = 0; i < len; ++i) {
2261:           const PetscInt *oldIndices = NULL;
2262:           PetscInt        nf, fi, pStarti, pEndi, fdof, cfdof, fc;

2264:           PetscCall(PetscSectionGetNumFields(s[i], &nf));
2265:           PetscCall(PetscSectionGetChart(s[i], &pStarti, &pEndi));
2266:           if ((p < pStarti) || (p >= pEndi)) continue;
2267:           for (fi = 0; fi < nf; ++fi, ++f) {
2268:             PetscCall(PetscSectionGetFieldDof(s[i], p, fi, &fdof));
2269:             PetscCall(PetscSectionGetFieldConstraintDof(s[i], p, fi, &cfdof));
2270:             PetscCall(PetscSectionGetFieldConstraintIndices(s[i], p, fi, &oldIndices));
2271:             for (fc = 0; fc < cfdof; ++fc) indices[numConst + fc] = oldIndices[fc];
2272:             PetscCall(PetscSectionSetFieldConstraintIndices(*supers, p, f, &indices[numConst]));
2273:             for (fc = 0; fc < cfdof; ++fc) indices[numConst + fc] += fOff;
2274:             numConst += cfdof;
2275:           }
2276:           PetscCall(PetscSectionGetDof(s[i], p, &dof));
2277:           fOff += dof;
2278:         }
2279:         PetscCall(PetscSectionSetConstraintIndices(*supers, p, indices));
2280:       }
2281:     }
2282:     PetscCall(PetscFree(indices));
2283:   }
2284:   PetscFunctionReturn(PETSC_SUCCESS);
2285: }

2287: static PetscErrorCode PetscSectionCreateSubplexSection_Private(PetscSection s, IS subpointIS, PetscBool renumberPoints, PetscSection *subs)
2288: {
2289:   const PetscInt *points = NULL, *indices = NULL;
2290:   PetscInt       *spoints = NULL, *order = NULL;
2291:   PetscInt        numFields, f, c, numSubpoints = 0, pStart, pEnd, p, spStart, spEnd, subp;

2293:   PetscFunctionBegin;
2296:   PetscAssertPointer(subs, 4);
2297:   PetscCall(PetscSectionGetNumFields(s, &numFields));
2298:   PetscCall(PetscSectionCreate(PetscObjectComm((PetscObject)s), subs));
2299:   if (numFields) PetscCall(PetscSectionSetNumFields(*subs, numFields));
2300:   for (f = 0; f < numFields; ++f) {
2301:     const char *name    = NULL;
2302:     PetscInt    numComp = 0;

2304:     PetscCall(PetscSectionGetFieldName(s, f, &name));
2305:     PetscCall(PetscSectionSetFieldName(*subs, f, name));
2306:     PetscCall(PetscSectionGetFieldComponents(s, f, &numComp));
2307:     PetscCall(PetscSectionSetFieldComponents(*subs, f, numComp));
2308:     for (c = 0; c < s->numFieldComponents[f]; ++c) {
2309:       PetscCall(PetscSectionGetComponentName(s, f, c, &name));
2310:       PetscCall(PetscSectionSetComponentName(*subs, f, c, name));
2311:     }
2312:   }
2313:   /* For right now, we do not try to squeeze the subchart */
2314:   if (subpointIS) {
2315:     PetscCall(ISGetLocalSize(subpointIS, &numSubpoints));
2316:     PetscCall(ISGetIndices(subpointIS, &points));
2317:   }
2318:   PetscCall(PetscSectionGetChart(s, &pStart, &pEnd));
2319:   if (renumberPoints) {
2320:     PetscBool sorted;

2322:     spStart = 0;
2323:     spEnd   = numSubpoints;
2324:     PetscCall(ISSorted(subpointIS, &sorted));
2325:     if (!sorted) {
2326:       PetscCall(PetscMalloc2(numSubpoints, &spoints, numSubpoints, &order));
2327:       PetscCall(PetscArraycpy(spoints, points, numSubpoints));
2328:       for (PetscInt i = 0; i < numSubpoints; ++i) order[i] = i;
2329:       PetscCall(PetscSortIntWithArray(numSubpoints, spoints, order));
2330:     }
2331:   } else {
2332:     PetscCall(ISGetMinMax(subpointIS, &spStart, &spEnd));
2333:     ++spEnd;
2334:   }
2335:   PetscCall(PetscSectionSetChart(*subs, spStart, spEnd));
2336:   for (p = pStart; p < pEnd; ++p) {
2337:     PetscInt dof, cdof, fdof = 0, cfdof = 0;

2339:     PetscCall(PetscFindInt(p, numSubpoints, spoints ? spoints : points, &subp));
2340:     if (subp < 0) continue;
2341:     if (!renumberPoints) subp = p;
2342:     else subp = order ? order[subp] : subp;
2343:     for (f = 0; f < numFields; ++f) {
2344:       PetscCall(PetscSectionGetFieldDof(s, p, f, &fdof));
2345:       PetscCall(PetscSectionSetFieldDof(*subs, subp, f, fdof));
2346:       PetscCall(PetscSectionGetFieldConstraintDof(s, p, f, &cfdof));
2347:       if (cfdof) PetscCall(PetscSectionSetFieldConstraintDof(*subs, subp, f, cfdof));
2348:     }
2349:     PetscCall(PetscSectionGetDof(s, p, &dof));
2350:     PetscCall(PetscSectionSetDof(*subs, subp, dof));
2351:     PetscCall(PetscSectionGetConstraintDof(s, p, &cdof));
2352:     if (cdof) PetscCall(PetscSectionSetConstraintDof(*subs, subp, cdof));
2353:   }
2354:   PetscCall(PetscSectionSetUp(*subs));
2355:   /* Change offsets to original offsets */
2356:   for (p = pStart; p < pEnd; ++p) {
2357:     PetscInt off, foff = 0;

2359:     PetscCall(PetscFindInt(p, numSubpoints, spoints ? spoints : points, &subp));
2360:     if (subp < 0) continue;
2361:     if (!renumberPoints) subp = p;
2362:     else subp = order ? order[subp] : subp;
2363:     for (f = 0; f < numFields; ++f) {
2364:       PetscCall(PetscSectionGetFieldOffset(s, p, f, &foff));
2365:       PetscCall(PetscSectionSetFieldOffset(*subs, subp, f, foff));
2366:     }
2367:     PetscCall(PetscSectionGetOffset(s, p, &off));
2368:     PetscCall(PetscSectionSetOffset(*subs, subp, off));
2369:   }
2370:   /* Copy constraint indices */
2371:   for (subp = spStart; subp < spEnd; ++subp) {
2372:     PetscInt cdof;

2374:     PetscCall(PetscSectionGetConstraintDof(*subs, subp, &cdof));
2375:     if (cdof) {
2376:       for (f = 0; f < numFields; ++f) {
2377:         PetscCall(PetscSectionGetFieldConstraintIndices(s, points[subp - spStart], f, &indices));
2378:         PetscCall(PetscSectionSetFieldConstraintIndices(*subs, subp, f, indices));
2379:       }
2380:       PetscCall(PetscSectionGetConstraintIndices(s, points[subp - spStart], &indices));
2381:       PetscCall(PetscSectionSetConstraintIndices(*subs, subp, indices));
2382:     }
2383:   }
2384:   if (subpointIS) PetscCall(ISRestoreIndices(subpointIS, &points));
2385:   PetscCall(PetscFree2(spoints, order));
2386:   PetscFunctionReturn(PETSC_SUCCESS);
2387: }

2389: /*@
2390:   PetscSectionCreateSubmeshSection - Create a new, smaller section with support on the submesh

2392:   Collective

2394:   Input Parameters:
2395: + s          - the `PetscSection`
2396: - subpointIS - a sorted list of points in the original mesh which are in the submesh

2398:   Output Parameter:
2399: . subs - the subsection

2401:   Level: advanced

2403:   Notes:
2404:   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))`

2406:   Compare this with `PetscSectionCreateSubdomainSection()` that does not map the points numbers to start at zero but leaves them as before

2408:   Developer Notes:
2409:   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`

2411: .seealso: [PetscSection](ch_petscsection), `PetscSection`, `PetscSectionCreateSubdomainSection()`, `PetscSectionCreateSubsection()`, `DMPlexGetSubpointMap()`, `PetscSectionCreate()`
2412: @*/
2413: PetscErrorCode PetscSectionCreateSubmeshSection(PetscSection s, IS subpointIS, PetscSection *subs)
2414: {
2415:   PetscFunctionBegin;
2416:   PetscCall(PetscSectionCreateSubplexSection_Private(s, subpointIS, PETSC_TRUE, subs));
2417:   PetscFunctionReturn(PETSC_SUCCESS);
2418: }

2420: /*@
2421:   PetscSectionCreateSubdomainSection - Create a new, smaller section with support on a subdomain of the mesh

2423:   Collective

2425:   Input Parameters:
2426: + s           - the `PetscSection`
2427: - subpointMap - a sorted list of points in the original mesh which are in the subdomain

2429:   Output Parameter:
2430: . subs - the subsection

2432:   Level: advanced

2434:   Notes:
2435:   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`
2436:   is `[min(subpointMap),max(subpointMap)+1)`

2438:   Compare this with `PetscSectionCreateSubmeshSection()` that maps the point numbers to start at zero

2440:   Developer Notes:
2441:   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`

2443: .seealso: [PetscSection](ch_petscsection), `PetscSection`, `PetscSectionCreateSubmeshSection()`, `PetscSectionCreateSubsection()`, `DMPlexGetSubpointMap()`, `PetscSectionCreate()`
2444: @*/
2445: PetscErrorCode PetscSectionCreateSubdomainSection(PetscSection s, IS subpointMap, PetscSection *subs)
2446: {
2447:   PetscFunctionBegin;
2448:   PetscCall(PetscSectionCreateSubplexSection_Private(s, subpointMap, PETSC_FALSE, subs));
2449:   PetscFunctionReturn(PETSC_SUCCESS);
2450: }

2452: static PetscErrorCode PetscSectionView_ASCII(PetscSection s, PetscViewer viewer)
2453: {
2454:   PetscMPIInt rank;

2456:   PetscFunctionBegin;
2457:   PetscCallMPI(MPI_Comm_rank(PetscObjectComm((PetscObject)viewer), &rank));
2458:   PetscCall(PetscViewerASCIIPushSynchronized(viewer));
2459:   PetscCall(PetscViewerASCIISynchronizedPrintf(viewer, "Process %d:\n", rank));
2460:   for (PetscInt p = 0; p < s->pEnd - s->pStart; ++p) {
2461:     if (s->bc && s->bc->atlasDof[p] > 0) {
2462:       PetscCall(PetscViewerASCIISynchronizedPrintf(viewer, "  (%4" PetscInt_FMT ") dof %2" PetscInt_FMT " offset %3" PetscInt_FMT " constrained", p + s->pStart, s->atlasDof[p], s->atlasOff[p]));
2463:       if (s->bcIndices) {
2464:         for (PetscInt b = 0; b < s->bc->atlasDof[p]; ++b) PetscCall(PetscViewerASCIISynchronizedPrintf(viewer, " %" PetscInt_FMT, s->bcIndices[s->bc->atlasOff[p] + b]));
2465:       }
2466:       PetscCall(PetscViewerASCIISynchronizedPrintf(viewer, "\n"));
2467:     } else {
2468:       PetscCall(PetscViewerASCIISynchronizedPrintf(viewer, "  (%4" PetscInt_FMT ") dof %2" PetscInt_FMT " offset %3" PetscInt_FMT "\n", p + s->pStart, s->atlasDof[p], s->atlasOff[p]));
2469:     }
2470:   }
2471:   PetscCall(PetscViewerFlush(viewer));
2472:   PetscCall(PetscViewerASCIIPopSynchronized(viewer));
2473:   if (s->sym) {
2474:     PetscCall(PetscViewerASCIIPushTab(viewer));
2475:     PetscCall(PetscSectionSymView(s->sym, viewer));
2476:     PetscCall(PetscViewerASCIIPopTab(viewer));
2477:   }
2478:   PetscFunctionReturn(PETSC_SUCCESS);
2479: }

2481: /*@
2482:   PetscSectionViewFromOptions - View the `PetscSection` based on values in the options database

2484:   Collective

2486:   Input Parameters:
2487: + A    - the `PetscSection` object to view
2488: . obj  - Optional object that provides the options prefix used for the options
2489: - name - command line option

2491:   Options Database Key:
2492: . -name [viewertype][:...] - option name and values. See `PetscObjectViewFromOptions()` for the possible arguments

2494:   Level: intermediate

2496: .seealso: [PetscSection](ch_petscsection), `PetscSection`, `PetscSectionView`, `PetscObjectViewFromOptions()`, `PetscSectionCreate()`, `PetscSectionView()`
2497: @*/
2498: PetscErrorCode PetscSectionViewFromOptions(PetscSection A, PetscObject obj, const char name[])
2499: {
2500:   PetscFunctionBegin;
2502:   PetscCall(PetscObjectViewFromOptions((PetscObject)A, obj, name));
2503:   PetscFunctionReturn(PETSC_SUCCESS);
2504: }

2506: /*@
2507:   PetscSectionView - Views a `PetscSection`

2509:   Collective

2511:   Input Parameters:
2512: + s      - the `PetscSection` object to view
2513: - viewer - the viewer

2515:   Level: beginner

2517:   Note:
2518:   `PetscSectionView()`, when viewer is of type `PETSCVIEWERHDF5`, only saves
2519:   distribution independent data, such as dofs, offsets, constraint dofs,
2520:   and constraint indices. Points that have negative dofs, for instance,
2521:   are not saved as they represent points owned by other processes.
2522:   Point numbering and rank assignment is currently not stored.
2523:   The saved section can be loaded with `PetscSectionLoad()`.

2525: .seealso: [PetscSection](ch_petscsection), `PetscSection`, `PetscSectionCreate()`, `PetscSectionDestroy()`, `PetscSectionLoad()`, `PetscViewer`
2526: @*/
2527: PetscErrorCode PetscSectionView(PetscSection s, PetscViewer viewer)
2528: {
2529:   PetscBool isascii, ishdf5;
2530:   PetscInt  f;

2532:   PetscFunctionBegin;
2534:   if (!viewer) PetscCall(PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)s), &viewer));
2536:   PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERASCII, &isascii));
2537:   PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERHDF5, &ishdf5));
2538:   if (isascii) {
2539:     PetscCall(PetscObjectPrintClassNamePrefixType((PetscObject)s, viewer));
2540:     if (s->numFields) {
2541:       PetscCall(PetscViewerASCIIPrintf(viewer, "%" PetscInt_FMT " fields\n", s->numFields));
2542:       for (f = 0; f < s->numFields; ++f) {
2543:         PetscCall(PetscViewerASCIIPrintf(viewer, "  field %" PetscInt_FMT " \"%s\" with %" PetscInt_FMT " components\n", f, s->fieldNames[f], s->numFieldComponents[f]));
2544:         PetscCall(PetscSectionView_ASCII(s->field[f], viewer));
2545:       }
2546:     } else {
2547:       PetscCall(PetscSectionView_ASCII(s, viewer));
2548:     }
2549:   } else if (ishdf5) {
2550: #if PetscDefined(HAVE_HDF5)
2551:     PetscCall(PetscSectionView_HDF5_Internal(s, viewer));
2552: #else
2553:     SETERRQ(PetscObjectComm((PetscObject)s), PETSC_ERR_SUP, "HDF5 not supported in this build.\nPlease reconfigure using --download-hdf5");
2554: #endif
2555:   }
2556:   PetscFunctionReturn(PETSC_SUCCESS);
2557: }

2559: /*@
2560:   PetscSectionLoad - Loads a `PetscSection`

2562:   Collective

2564:   Input Parameters:
2565: + s      - the `PetscSection` object to load
2566: - viewer - the viewer

2568:   Level: beginner

2570:   Note:
2571:   `PetscSectionLoad()`, when viewer is of type `PETSCVIEWERHDF5`, loads
2572:   a section saved with `PetscSectionView()`. The number of processes
2573:   used here (N) does not need to be the same as that used when saving.
2574:   After calling this function, the chart of s on rank i will be set
2575:   to [0, E_i), where \sum_{i=0}^{N-1}E_i equals to the total number of
2576:   saved section points.

2578: .seealso: [PetscSection](ch_petscsection), `PetscSection`, `PetscSectionCreate()`, `PetscSectionDestroy()`, `PetscSectionView()`
2579: @*/
2580: PetscErrorCode PetscSectionLoad(PetscSection s, PetscViewer viewer)
2581: {
2582:   PetscBool ishdf5;

2584:   PetscFunctionBegin;
2587:   PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERHDF5, &ishdf5));
2588:   PetscCheck(ishdf5, PetscObjectComm((PetscObject)s), PETSC_ERR_SUP, "Viewer type %s not yet supported for PetscSection loading", ((PetscObject)viewer)->type_name);
2589: #if PetscDefined(HAVE_HDF5)
2590:   PetscCall(PetscSectionLoad_HDF5_Internal(s, viewer));
2591:   PetscFunctionReturn(PETSC_SUCCESS);
2592: #else
2593:   SETERRQ(PetscObjectComm((PetscObject)s), PETSC_ERR_SUP, "HDF5 not supported in this build.\nPlease reconfigure using --download-hdf5");
2594: #endif
2595: }

2597: static inline PetscErrorCode PrintArrayElement(void *array, PetscDataType data_type, PetscCount index, PetscViewer viewer)
2598: {
2599:   PetscFunctionBeginUser;
2600:   switch (data_type) {
2601:   case PETSC_INT: {
2602:     PetscCall(PetscViewerASCIISynchronizedPrintf(viewer, " %2" PetscInt_FMT, ((PetscInt *)array)[index]));
2603:     break;
2604:   }
2605:   case PETSC_INT32: {
2606:     PetscCall(PetscViewerASCIISynchronizedPrintf(viewer, " %2" PetscInt32_FMT, ((PetscInt32 *)array)[index]));
2607:     break;
2608:   }
2609:   case PETSC_INT64: {
2610:     PetscCall(PetscViewerASCIISynchronizedPrintf(viewer, " %2" PetscInt64_FMT, ((PetscInt64 *)array)[index]));
2611:     break;
2612:   }
2613:   case PETSC_COUNT: {
2614:     PetscCall(PetscViewerASCIISynchronizedPrintf(viewer, " %2" PetscCount_FMT, ((PetscCount *)array)[index]));
2615:     break;
2616:   }
2617:   // PETSC_SCALAR is set to the appropriate type
2618:   case PETSC_DOUBLE: {
2619:     PetscCall(PetscViewerASCIISynchronizedPrintf(viewer, " %g", ((double *)array)[index]));
2620:     break;
2621:   }
2622:   case PETSC_FLOAT: {
2623:     PetscCall(PetscViewerASCIISynchronizedPrintf(viewer, " %g", (double)((float *)array)[index]));
2624:     break;
2625:   }
2626: #if PetscDefined(USE_REAL___FLOAT128)
2627:   case PETSC___FLOAT128: {
2628:     PetscCall(PetscViewerASCIISynchronizedPrintf(viewer, " %g", (double)((PetscReal *)array)[index]));
2629:     break;
2630:   }
2631: #endif
2632: #if PetscDefined(USE_REAL___FP16)
2633:   case PETSC___FP16: {
2634:     PetscCall(PetscViewerASCIISynchronizedPrintf(viewer, " %g", (double)((PetscReal *)array)[index]));
2635:     break;
2636:   }
2637: #endif
2638: #if PetscDefined(HAVE_COMPLEX)
2639:   case PETSC_COMPLEX: {
2640:     PetscComplex v = ((PetscComplex *)array)[index];
2641:     if (PetscImaginaryPartComplex(v) > 0.0) {
2642:       PetscCall(PetscViewerASCIISynchronizedPrintf(viewer, " %g + %g i", (double)PetscRealPartComplex(v), (double)PetscImaginaryPartComplex(v)));
2643:     } else if (PetscImaginaryPartComplex(v) < 0.0) {
2644:       PetscCall(PetscViewerASCIISynchronizedPrintf(viewer, " %g - %g i", (double)PetscRealPartComplex(v), (double)(-PetscImaginaryPartComplex(v))));
2645:     } else {
2646:       PetscCall(PetscViewerASCIISynchronizedPrintf(viewer, " %g", (double)PetscRealPartComplex(v)));
2647:     }
2648:     break;
2649:   }
2650: #endif
2651:   default:
2652:     SETERRQ(PetscObjectComm((PetscObject)viewer), PETSC_ERR_SUP, "PetscDataType %d (%s) not supported", data_type, PetscDataTypes[data_type]);
2653:   }
2654:   PetscFunctionReturn(PETSC_SUCCESS);
2655: }

2657: PetscErrorCode PetscSectionArrayView_ASCII_Internal(PetscSection s, void *array, PetscDataType data_type, PetscViewer viewer)
2658: {
2659:   PetscInt    i;
2660:   PetscMPIInt rank;

2662:   PetscFunctionBegin;
2663:   PetscCallMPI(MPI_Comm_rank(PetscObjectComm((PetscObject)viewer), &rank));
2664:   PetscCall(PetscViewerASCIIPushSynchronized(viewer));
2665:   PetscCall(PetscViewerASCIISynchronizedPrintf(viewer, "Process %d:\n", rank));
2666:   for (PetscInt p = 0; p < s->pEnd - s->pStart; ++p) {
2667:     if (s->bc && (s->bc->atlasDof[p] > 0)) {
2668:       PetscCall(PetscViewerASCIISynchronizedPrintf(viewer, "  (%4" PetscInt_FMT ") dof %2" PetscInt_FMT " offset %3" PetscInt_FMT, p + s->pStart, s->atlasDof[p], s->atlasOff[p]));
2669:       for (i = s->atlasOff[p]; i < s->atlasOff[p] + s->atlasDof[p]; ++i) PetscCall(PrintArrayElement(array, data_type, i, viewer));
2670:       PetscCall(PetscViewerASCIISynchronizedPrintf(viewer, " constrained"));
2671:       for (PetscInt b = 0; b < s->bc->atlasDof[p]; ++b) PetscCall(PetscViewerASCIISynchronizedPrintf(viewer, " %" PetscInt_FMT, s->bcIndices[s->bc->atlasOff[p] + b]));
2672:       PetscCall(PetscViewerASCIISynchronizedPrintf(viewer, "\n"));
2673:     } else {
2674:       PetscCall(PetscViewerASCIISynchronizedPrintf(viewer, "  (%4" PetscInt_FMT ") dof %2" PetscInt_FMT " offset %3" PetscInt_FMT, p + s->pStart, s->atlasDof[p], s->atlasOff[p]));
2675:       for (i = s->atlasOff[p]; i < s->atlasOff[p] + s->atlasDof[p]; ++i) PetscCall(PrintArrayElement(array, data_type, i, viewer));
2676:       PetscCall(PetscViewerASCIISynchronizedPrintf(viewer, "\n"));
2677:     }
2678:   }
2679:   PetscCall(PetscViewerFlush(viewer));
2680:   PetscCall(PetscViewerASCIIPopSynchronized(viewer));
2681:   PetscFunctionReturn(PETSC_SUCCESS);
2682: }

2684: /*@
2685:   PetscSectionArrayView - View an array, using the section to structure the values

2687:   Collective

2689:   Input Parameters:
2690: + s         - the organizing `PetscSection`
2691: . array     - the array of values
2692: . data_type - the `PetscDataType` of the array
2693: - viewer    - the `PetscViewer`

2695:   Level: developer

2697: .seealso: `PetscSection`, `PetscViewer`, `PetscSectionCreate()`, `VecSetValuesSection()`, `PetscSectionVecView()`
2698: @*/
2699: PetscErrorCode PetscSectionArrayView(PetscSection s, void *array, PetscDataType data_type, PetscViewer viewer)
2700: {
2701:   PetscBool isascii;
2702:   PetscInt  f;

2704:   PetscFunctionBegin;
2706:   if (!array) {
2707:     PetscInt size;
2708:     PetscCall(PetscSectionGetStorageSize(s, &size));
2709:     PetscCheck(size == 0, PetscObjectComm((PetscObject)s), PETSC_ERR_ARG_SIZ, "NULL array passed, but section's storage size is non-zero");
2710:   } else PetscAssertPointer(array, 2);
2711:   if (!viewer) PetscCall(PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)s), &viewer));
2713:   PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERASCII, &isascii));
2714:   if (isascii) {
2715:     if (s->numFields) {
2716:       PetscCall(PetscViewerASCIIPrintf(viewer, "Array with %" PetscInt_FMT " fields\n", s->numFields));
2717:       for (f = 0; f < s->numFields; ++f) {
2718:         PetscCall(PetscViewerASCIIPrintf(viewer, "  field %" PetscInt_FMT " with %" PetscInt_FMT " components\n", f, s->numFieldComponents[f]));
2719:         PetscCall(PetscSectionArrayView_ASCII_Internal(s->field[f], array, data_type, viewer));
2720:       }
2721:     } else {
2722:       PetscCall(PetscSectionArrayView_ASCII_Internal(s, array, data_type, viewer));
2723:     }
2724:   }
2725:   PetscFunctionReturn(PETSC_SUCCESS);
2726: }

2728: /*@
2729:   PetscSectionResetClosurePermutation - Remove any existing closure permutation

2731:   Input Parameter:
2732: . section - The `PetscSection`

2734:   Level: intermediate

2736: .seealso: `PetscSectionSetClosurePermutation()`, `PetscSectionSetClosureIndex()`, `PetscSectionReset()`
2737: @*/
2738: PetscErrorCode PetscSectionResetClosurePermutation(PetscSection section)
2739: {
2740:   PetscSectionClosurePermVal clVal;

2742:   PetscFunctionBegin;
2743:   if (!section->clHash) PetscFunctionReturn(PETSC_SUCCESS);
2744:   kh_foreach_value(section->clHash, clVal, {
2745:     PetscCall(PetscFree(clVal.perm));
2746:     PetscCall(PetscFree(clVal.invPerm));
2747:   });
2748:   kh_destroy(ClPerm, section->clHash);
2749:   section->clHash = NULL;
2750:   PetscFunctionReturn(PETSC_SUCCESS);
2751: }

2753: /*@
2754:   PetscSectionReset - Frees all section data, the section is then as if `PetscSectionCreate()` had just been called.

2756:   Not Collective

2758:   Input Parameter:
2759: . s - the `PetscSection`

2761:   Level: beginner

2763: .seealso: [PetscSection](ch_petscsection), `PetscSection`, `PetscSectionCreate()`
2764: @*/
2765: PetscErrorCode PetscSectionReset(PetscSection s)
2766: {
2767:   PetscInt f, c;

2769:   PetscFunctionBegin;
2771:   for (f = 0; f < s->numFields; ++f) {
2772:     PetscCall(PetscSectionDestroy(&s->field[f]));
2773:     PetscCall(PetscFree(s->fieldNames[f]));
2774:     for (c = 0; c < s->numFieldComponents[f]; ++c) PetscCall(PetscFree(s->compNames[f][c]));
2775:     PetscCall(PetscFree(s->compNames[f]));
2776:   }
2777:   PetscCall(PetscFree(s->numFieldComponents));
2778:   PetscCall(PetscFree(s->fieldNames));
2779:   PetscCall(PetscFree(s->compNames));
2780:   PetscCall(PetscFree(s->field));
2781:   PetscCall(PetscSectionDestroy(&s->bc));
2782:   PetscCall(PetscFree(s->bcIndices));
2783:   PetscCall(PetscFree2(s->atlasDof, s->atlasOff));
2784:   PetscCall(PetscSectionDestroy(&s->clSection));
2785:   PetscCall(ISDestroy(&s->clPoints));
2786:   PetscCall(ISDestroy(&s->perm));
2787:   PetscCall(PetscBTDestroy(&s->blockStarts));
2788:   PetscCall(PetscSectionResetClosurePermutation(s));
2789:   PetscCall(PetscSectionSymDestroy(&s->sym));
2790:   PetscCall(PetscSectionDestroy(&s->clSection));
2791:   PetscCall(ISDestroy(&s->clPoints));
2792:   PetscCall(PetscSectionInvalidateMaxDof_Internal(s));
2793:   s->pStart    = -1;
2794:   s->pEnd      = -1;
2795:   s->maxDof    = 0;
2796:   s->setup     = PETSC_FALSE;
2797:   s->numFields = 0;
2798:   s->clObj     = NULL;
2799:   PetscFunctionReturn(PETSC_SUCCESS);
2800: }

2802: /*@
2803:   PetscSectionDestroy - Frees a `PetscSection`

2805:   Not Collective

2807:   Input Parameter:
2808: . s - the `PetscSection`

2810:   Level: beginner

2812: .seealso: [PetscSection](ch_petscsection), `PetscSection`, `PetscSectionCreate()`, `PetscSectionReset()`
2813: @*/
2814: PetscErrorCode PetscSectionDestroy(PetscSection *s)
2815: {
2816:   PetscFunctionBegin;
2817:   if (!*s) PetscFunctionReturn(PETSC_SUCCESS);
2819:   if (--((PetscObject)*s)->refct > 0) {
2820:     *s = NULL;
2821:     PetscFunctionReturn(PETSC_SUCCESS);
2822:   }
2823:   PetscCall(PetscSectionReset(*s));
2824:   PetscCall(PetscHeaderDestroy(s));
2825:   PetscFunctionReturn(PETSC_SUCCESS);
2826: }

2828: static PetscErrorCode VecIntGetValuesSection_Private(const PetscInt *baseArray, PetscSection s, PetscInt point, const PetscInt **values)
2829: {
2830:   const PetscInt p = point - s->pStart;

2832:   PetscFunctionBegin;
2834:   *values = &baseArray[s->atlasOff[p]];
2835:   PetscFunctionReturn(PETSC_SUCCESS);
2836: }

2838: static PetscErrorCode VecIntSetValuesSection_Private(PetscInt *baseArray, PetscSection s, PetscInt point, const PetscInt values[], InsertMode mode)
2839: {
2840:   PetscInt      *array;
2841:   const PetscInt p           = point - s->pStart;
2842:   const PetscInt orientation = 0; /* Needs to be included for use in closure operations */
2843:   PetscInt       cDim        = 0;

2845:   PetscFunctionBegin;
2847:   PetscCall(PetscSectionGetConstraintDof(s, p, &cDim));
2848:   array = &baseArray[s->atlasOff[p]];
2849:   if (!cDim) {
2850:     if (orientation >= 0) {
2851:       const PetscInt dim = s->atlasDof[p];
2852:       PetscInt       i;

2854:       if (mode == INSERT_VALUES) {
2855:         for (i = 0; i < dim; ++i) array[i] = values ? values[i] : i;
2856:       } else {
2857:         for (i = 0; i < dim; ++i) array[i] += values[i];
2858:       }
2859:     } else {
2860:       PetscInt offset = 0;
2861:       PetscInt j      = -1, field, i;

2863:       for (field = 0; field < s->numFields; ++field) {
2864:         const PetscInt dim = s->field[field]->atlasDof[p];

2866:         for (i = dim - 1; i >= 0; --i) array[++j] = values ? values[i + offset] : i + offset;
2867:         offset += dim;
2868:       }
2869:     }
2870:   } else {
2871:     if (orientation >= 0) {
2872:       const PetscInt  dim  = s->atlasDof[p];
2873:       PetscInt        cInd = 0, i;
2874:       const PetscInt *cDof;

2876:       PetscCall(PetscSectionGetConstraintIndices(s, point, &cDof));
2877:       if (mode == INSERT_VALUES) {
2878:         for (i = 0; i < dim; ++i) {
2879:           if ((cInd < cDim) && (i == cDof[cInd])) {
2880:             ++cInd;
2881:             continue;
2882:           }
2883:           array[i] = values ? values[i] : i;
2884:         }
2885:       } else {
2886:         for (i = 0; i < dim; ++i) {
2887:           if ((cInd < cDim) && (i == cDof[cInd])) {
2888:             ++cInd;
2889:             continue;
2890:           }
2891:           array[i] += values[i];
2892:         }
2893:       }
2894:     } else {
2895:       const PetscInt *cDof;
2896:       PetscInt        offset  = 0;
2897:       PetscInt        cOffset = 0;
2898:       PetscInt        j       = 0, field;

2900:       PetscCall(PetscSectionGetConstraintIndices(s, point, &cDof));
2901:       for (field = 0; field < s->numFields; ++field) {
2902:         const PetscInt dim  = s->field[field]->atlasDof[p];     /* PetscSectionGetFieldDof() */
2903:         const PetscInt tDim = s->field[field]->bc->atlasDof[p]; /* PetscSectionGetFieldConstraintDof() */
2904:         const PetscInt sDim = dim - tDim;
2905:         PetscInt       cInd = 0, i, k;

2907:         for (i = 0, k = dim + offset - 1; i < dim; ++i, ++j, --k) {
2908:           if ((cInd < sDim) && (j == cDof[cInd + cOffset])) {
2909:             ++cInd;
2910:             continue;
2911:           }
2912:           array[j] = values ? values[k] : k;
2913:         }
2914:         offset += dim;
2915:         cOffset += dim - tDim;
2916:       }
2917:     }
2918:   }
2919:   PetscFunctionReturn(PETSC_SUCCESS);
2920: }

2922: /*@
2923:   PetscSectionHasConstraints - Determine whether a `PetscSection` has constrained dofs

2925:   Not Collective

2927:   Input Parameter:
2928: . s - The `PetscSection`

2930:   Output Parameter:
2931: . hasConstraints - flag indicating that the section has constrained dofs

2933:   Level: intermediate

2935: .seealso: [PetscSection](ch_petscsection), `PetscSectionSetConstraintIndices()`, `PetscSectionGetConstraintDof()`, `PetscSection`
2936: @*/
2937: PetscErrorCode PetscSectionHasConstraints(PetscSection s, PetscBool *hasConstraints)
2938: {
2939:   PetscFunctionBegin;
2941:   PetscAssertPointer(hasConstraints, 2);
2942:   *hasConstraints = s->bc ? PETSC_TRUE : PETSC_FALSE;
2943:   PetscFunctionReturn(PETSC_SUCCESS);
2944: }

2946: /*@C
2947:   PetscSectionGetConstraintIndices - Get the point dof numbers, in [0, dof), which are constrained for a given point

2949:   Not Collective

2951:   Input Parameters:
2952: + s     - The `PetscSection`
2953: - point - The point

2955:   Output Parameter:
2956: . indices - The constrained dofs

2958:   Level: intermediate

2960:   Fortran Notes:
2961:   Use `PetscSectionRestoreConstraintIndices()` when the indices are no longer needed

2963: .seealso: [PetscSection](ch_petscsection), `PetscSectionSetConstraintIndices()`, `PetscSectionGetConstraintDof()`, `PetscSection`
2964: @*/
2965: PetscErrorCode PetscSectionGetConstraintIndices(PetscSection s, PetscInt point, const PetscInt *indices[])
2966: {
2967:   PetscFunctionBegin;
2969:   if (s->bc) PetscCall(VecIntGetValuesSection_Private(s->bcIndices, s->bc, point, indices));
2970:   else *indices = NULL;
2971:   PetscFunctionReturn(PETSC_SUCCESS);
2972: }

2974: /*@
2975:   PetscSectionSetConstraintIndices - Set the point dof numbers, in [0, dof), which are constrained

2977:   Not Collective

2979:   Input Parameters:
2980: + s       - The `PetscSection`
2981: . point   - The point
2982: - indices - The constrained dofs

2984:   Level: intermediate

2986: .seealso: [PetscSection](ch_petscsection), `PetscSectionGetConstraintIndices()`, `PetscSectionGetConstraintDof()`, `PetscSection`
2987: @*/
2988: PetscErrorCode PetscSectionSetConstraintIndices(PetscSection s, PetscInt point, const PetscInt indices[])
2989: {
2990:   PetscFunctionBegin;
2992:   if (s->bc) {
2993:     const PetscInt dof  = s->atlasDof[point];
2994:     const PetscInt cdof = s->bc->atlasDof[point];
2995:     if (indices)
2996:       for (PetscInt d = 0; d < cdof; ++d)
2997:         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]);
2998:     PetscCall(VecIntSetValuesSection_Private(s->bcIndices, s->bc, point, indices, INSERT_VALUES));
2999:   }
3000:   PetscFunctionReturn(PETSC_SUCCESS);
3001: }

3003: /*@C
3004:   PetscSectionGetFieldConstraintIndices - Get the field dof numbers, in [0, fdof), which are constrained

3006:   Not Collective

3008:   Input Parameters:
3009: + s     - The `PetscSection`
3010: . field - The field number
3011: - point - The point

3013:   Output Parameter:
3014: . indices - The constrained dofs sorted in ascending order, the length is returned by `PetscSectionGetConstraintDof()`.

3016:   Level: intermediate

3018:   Fortran Notes:
3019:   Use `PetscSectionRestoreFieldConstraintIndices()` to restore the indices when no longer needed

3021: .seealso: [PetscSection](ch_petscsection), `PetscSectionSetFieldConstraintIndices()`, `PetscSectionGetConstraintIndices()`, `PetscSectionGetConstraintDof()`, `PetscSection`
3022: @*/
3023: PetscErrorCode PetscSectionGetFieldConstraintIndices(PetscSection s, PetscInt point, PetscInt field, const PetscInt *indices[])
3024: {
3025:   PetscFunctionBegin;
3027:   PetscAssertPointer(indices, 4);
3028:   PetscSectionCheckValidField(field, s->numFields);
3029:   PetscCall(PetscSectionGetConstraintIndices(s->field[field], point, indices));
3030:   PetscFunctionReturn(PETSC_SUCCESS);
3031: }

3033: /*@
3034:   PetscSectionSetFieldConstraintIndices - Set the field dof numbers, in [0, fdof), which are constrained

3036:   Not Collective

3038:   Input Parameters:
3039: + s       - The `PetscSection`
3040: . point   - The point
3041: . field   - The field number
3042: - indices - The constrained dofs

3044:   Level: intermediate

3046: .seealso: [PetscSection](ch_petscsection), `PetscSectionSetConstraintIndices()`, `PetscSectionGetFieldConstraintIndices()`, `PetscSectionGetConstraintDof()`, `PetscSection`
3047: @*/
3048: PetscErrorCode PetscSectionSetFieldConstraintIndices(PetscSection s, PetscInt point, PetscInt field, const PetscInt indices[])
3049: {
3050:   PetscFunctionBegin;
3052:   PetscSectionCheckValidField(field, s->numFields);
3053:   PetscCall(PetscSectionSetConstraintIndices(s->field[field], point, indices));
3054:   PetscFunctionReturn(PETSC_SUCCESS);
3055: }

3057: /*@
3058:   PetscSectionPermute - Reorder the section according to the input point permutation

3060:   Collective

3062:   Input Parameters:
3063: + section     - The `PetscSection` object
3064: - permutation - The point permutation, old point p becomes new point perm[p]

3066:   Output Parameter:
3067: . sectionNew - The permuted `PetscSection`

3069:   Level: intermediate

3071:   Note:
3072:   The data and the access to the data via `PetscSectionGetFieldOffset()` and `PetscSectionGetOffset()` are both changed in `sectionNew`

3074:   Compare to `PetscSectionSetPermutation()`

3076: .seealso: [PetscSection](ch_petscsection), `IS`, `PetscSection`, `MatPermute()`, `PetscSectionSetPermutation()`
3077: @*/
3078: PetscErrorCode PetscSectionPermute(PetscSection section, IS permutation, PetscSection *sectionNew)
3079: {
3080:   PetscSection    s = section, sNew;
3081:   const PetscInt *perm;
3082:   PetscInt        numFields, f, c, numPoints, pStart, pEnd, p;

3084:   PetscFunctionBegin;
3087:   PetscAssertPointer(sectionNew, 3);
3088:   PetscCall(PetscSectionCreate(PetscObjectComm((PetscObject)s), &sNew));
3089:   PetscCall(PetscSectionGetNumFields(s, &numFields));
3090:   if (numFields) PetscCall(PetscSectionSetNumFields(sNew, numFields));
3091:   for (f = 0; f < numFields; ++f) {
3092:     const char *name;
3093:     PetscInt    numComp;

3095:     PetscCall(PetscSectionGetFieldName(s, f, &name));
3096:     PetscCall(PetscSectionSetFieldName(sNew, f, name));
3097:     PetscCall(PetscSectionGetFieldComponents(s, f, &numComp));
3098:     PetscCall(PetscSectionSetFieldComponents(sNew, f, numComp));
3099:     for (c = 0; c < s->numFieldComponents[f]; ++c) {
3100:       PetscCall(PetscSectionGetComponentName(s, f, c, &name));
3101:       PetscCall(PetscSectionSetComponentName(sNew, f, c, name));
3102:     }
3103:   }
3104:   PetscCall(ISGetLocalSize(permutation, &numPoints));
3105:   PetscCall(ISGetIndices(permutation, &perm));
3106:   PetscCall(PetscSectionGetChart(s, &pStart, &pEnd));
3107:   PetscCall(PetscSectionSetChart(sNew, pStart, pEnd));
3108:   PetscCheck(numPoints >= pEnd, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Permutation size %" PetscInt_FMT " is less than largest Section point %" PetscInt_FMT, numPoints, pEnd);
3109:   for (p = pStart; p < pEnd; ++p) {
3110:     PetscInt dof, cdof;

3112:     PetscCall(PetscSectionGetDof(s, p, &dof));
3113:     PetscCall(PetscSectionSetDof(sNew, perm[p], dof));
3114:     PetscCall(PetscSectionGetConstraintDof(s, p, &cdof));
3115:     if (cdof) PetscCall(PetscSectionSetConstraintDof(sNew, perm[p], cdof));
3116:     for (f = 0; f < numFields; ++f) {
3117:       PetscCall(PetscSectionGetFieldDof(s, p, f, &dof));
3118:       PetscCall(PetscSectionSetFieldDof(sNew, perm[p], f, dof));
3119:       PetscCall(PetscSectionGetFieldConstraintDof(s, p, f, &cdof));
3120:       if (cdof) PetscCall(PetscSectionSetFieldConstraintDof(sNew, perm[p], f, cdof));
3121:     }
3122:   }
3123:   PetscCall(PetscSectionSetUp(sNew));
3124:   for (p = pStart; p < pEnd; ++p) {
3125:     const PetscInt *cind;
3126:     PetscInt        cdof;

3128:     PetscCall(PetscSectionGetConstraintDof(s, p, &cdof));
3129:     if (cdof) {
3130:       PetscCall(PetscSectionGetConstraintIndices(s, p, &cind));
3131:       PetscCall(PetscSectionSetConstraintIndices(sNew, perm[p], cind));
3132:     }
3133:     for (f = 0; f < numFields; ++f) {
3134:       PetscCall(PetscSectionGetFieldConstraintDof(s, p, f, &cdof));
3135:       if (cdof) {
3136:         PetscCall(PetscSectionGetFieldConstraintIndices(s, p, f, &cind));
3137:         PetscCall(PetscSectionSetFieldConstraintIndices(sNew, perm[p], f, cind));
3138:       }
3139:     }
3140:   }
3141:   PetscCall(ISRestoreIndices(permutation, &perm));
3142:   *sectionNew = sNew;
3143:   PetscFunctionReturn(PETSC_SUCCESS);
3144: }

3146: /*@
3147:   PetscSectionSetClosureIndex - Create an internal data structure to speed up closure queries.

3149:   Collective

3151:   Input Parameters:
3152: + section   - The `PetscSection`
3153: . obj       - A `PetscObject` which serves as the key for this index
3154: . clSection - `PetscSection` giving the size of the closure of each point
3155: - clPoints  - `IS` giving the points in each closure

3157:   Level: advanced

3159:   Note:
3160:   This function creates an internal map from each point to its closure. We compress out closure points with no dofs in this section.

3162:   Developer Notes:
3163:   The information provided here is completely opaque

3165: .seealso: [PetscSection](ch_petscsection), `PetscSection`, `PetscSectionGetClosureIndex()`, `DMPlexCreateClosureIndex()`
3166: @*/
3167: PetscErrorCode PetscSectionSetClosureIndex(PetscSection section, PetscObject obj, PetscSection clSection, IS clPoints)
3168: {
3169:   PetscFunctionBegin;
3173:   if (section->clObj != obj) PetscCall(PetscSectionResetClosurePermutation(section));
3174:   section->clObj = obj;
3175:   PetscCall(PetscObjectReference((PetscObject)clSection));
3176:   PetscCall(PetscObjectReference((PetscObject)clPoints));
3177:   PetscCall(PetscSectionDestroy(&section->clSection));
3178:   PetscCall(ISDestroy(&section->clPoints));
3179:   section->clSection = clSection;
3180:   section->clPoints  = clPoints;
3181:   PetscFunctionReturn(PETSC_SUCCESS);
3182: }

3184: /*@
3185:   PetscSectionGetClosureIndex - Get the cache of points in the closure of each point in the section set with `PetscSectionSetClosureIndex()`

3187:   Collective

3189:   Input Parameters:
3190: + section - The `PetscSection`
3191: - obj     - A `PetscObject` which serves as the key for this index

3193:   Output Parameters:
3194: + clSection - `PetscSection` giving the size of the closure of each point
3195: - clPoints  - `IS` giving the points in each closure

3197:   Level: advanced

3199: .seealso: [PetscSection](ch_petscsection), `PetscSectionSetClosureIndex()`, `DMPlexCreateClosureIndex()`
3200: @*/
3201: PetscErrorCode PetscSectionGetClosureIndex(PetscSection section, PetscObject obj, PetscSection *clSection, IS *clPoints)
3202: {
3203:   PetscFunctionBegin;
3204:   if (section->clObj == obj) {
3205:     if (clSection) *clSection = section->clSection;
3206:     if (clPoints) *clPoints = section->clPoints;
3207:   } else {
3208:     if (clSection) *clSection = NULL;
3209:     if (clPoints) *clPoints = NULL;
3210:   }
3211:   PetscFunctionReturn(PETSC_SUCCESS);
3212: }

3214: PetscErrorCode PetscSectionSetClosurePermutation_Internal(PetscSection section, PetscObject obj, PetscInt depth, PetscInt clSize, PetscCopyMode mode, PetscInt *clPerm)
3215: {
3216:   khiter_t                    iter;
3217:   int                         new_entry;
3218:   PetscSectionClosurePermKey  key = {depth, clSize};
3219:   PetscSectionClosurePermVal *val;

3221:   PetscFunctionBegin;
3222:   if (section->clObj != obj) {
3223:     PetscCall(PetscSectionDestroy(&section->clSection));
3224:     PetscCall(ISDestroy(&section->clPoints));
3225:   }
3226:   section->clObj = obj;
3227:   if (!section->clHash) PetscCall(PetscClPermCreate(&section->clHash));
3228:   iter = kh_put(ClPerm, section->clHash, key, &new_entry);
3229:   val  = &kh_val(section->clHash, iter);
3230:   if (!new_entry) {
3231:     PetscCall(PetscFree(val->perm));
3232:     PetscCall(PetscFree(val->invPerm));
3233:   }
3234:   if (mode == PETSC_COPY_VALUES) {
3235:     PetscCall(PetscMalloc1(clSize, &val->perm));
3236:     PetscCall(PetscArraycpy(val->perm, clPerm, clSize));
3237:   } else if (mode == PETSC_OWN_POINTER) {
3238:     val->perm = clPerm;
3239:   } else SETERRQ(PetscObjectComm(obj), PETSC_ERR_SUP, "Do not support borrowed arrays");
3240:   PetscCall(PetscMalloc1(clSize, &val->invPerm));
3241:   for (PetscInt i = 0; i < clSize; ++i) val->invPerm[clPerm[i]] = i;
3242:   PetscFunctionReturn(PETSC_SUCCESS);
3243: }

3245: /*@
3246:   PetscSectionSetClosurePermutation - Set the dof permutation for the closure of each cell in the section, meaning clPerm[newIndex] = oldIndex.

3248:   Not Collective

3250:   Input Parameters:
3251: + section - The `PetscSection`
3252: . obj     - A `PetscObject` which serves as the key for this index (usually a `DM`)
3253: . depth   - Depth of points on which to apply the given permutation
3254: - perm    - Permutation of the cell dof closure

3256:   Level: intermediate

3258:   Notes:
3259:   The specified permutation will only be applied to points at depth whose closure size matches the length of perm.  In a
3260:   mixed-topology or variable-degree finite element space, this function can be called multiple times at each depth for
3261:   each topology and degree.

3263:   This approach assumes that (depth, len(perm)) uniquely identifies the desired permutation; this might not be true for
3264:   exotic/enriched spaces on mixed topology meshes.

3266: .seealso: [PetscSection](ch_petscsection), `PetscSection`, `IS`, `PetscSectionGetClosurePermutation()`, `PetscSectionGetClosureIndex()`, `DMPlexCreateClosureIndex()`, `PetscCopyMode`
3267: @*/
3268: PetscErrorCode PetscSectionSetClosurePermutation(PetscSection section, PetscObject obj, PetscInt depth, IS perm)
3269: {
3270:   const PetscInt *clPerm = NULL;
3271:   PetscInt        clSize = 0;

3273:   PetscFunctionBegin;
3274:   if (perm) {
3275:     PetscCall(ISGetLocalSize(perm, &clSize));
3276:     PetscCall(ISGetIndices(perm, &clPerm));
3277:   }
3278:   PetscCall(PetscSectionSetClosurePermutation_Internal(section, obj, depth, clSize, PETSC_COPY_VALUES, (PetscInt *)clPerm));
3279:   if (perm) PetscCall(ISRestoreIndices(perm, &clPerm));
3280:   PetscFunctionReturn(PETSC_SUCCESS);
3281: }

3283: static PetscErrorCode PetscSectionGetClosurePermutation_Private(PetscSection section, PetscObject obj, PetscInt depth, PetscInt size, const PetscInt *perm[])
3284: {
3285:   PetscFunctionBegin;
3286:   if (section->clObj == obj) {
3287:     PetscSectionClosurePermKey k = {depth, size};
3288:     PetscSectionClosurePermVal v;

3290:     PetscCall(PetscClPermGet(section->clHash, k, &v));
3291:     if (perm) *perm = v.perm;
3292:   } else {
3293:     if (perm) *perm = NULL;
3294:   }
3295:   PetscFunctionReturn(PETSC_SUCCESS);
3296: }

3298: /*@
3299:   PetscSectionGetClosurePermutation - Get the dof permutation for the closure of each cell in the section, meaning clPerm[newIndex] = oldIndex.

3301:   Not Collective

3303:   Input Parameters:
3304: + section - The `PetscSection`
3305: . obj     - A `PetscObject` which serves as the key for this index (usually a DM)
3306: . depth   - Depth stratum on which to obtain closure permutation
3307: - clSize  - Closure size to be permuted (e.g., may vary with element topology and degree)

3309:   Output Parameter:
3310: . perm - The dof closure permutation

3312:   Level: intermediate

3314:   Note:
3315:   The user must destroy the `IS` that is returned.

3317: .seealso: [PetscSection](ch_petscsection), `PetscSection`, `IS`, `PetscSectionSetClosurePermutation()`, `PetscSectionGetClosureInversePermutation()`, `PetscSectionGetClosureIndex()`, `PetscSectionSetClosureIndex()`, `DMPlexCreateClosureIndex()`
3318: @*/
3319: PetscErrorCode PetscSectionGetClosurePermutation(PetscSection section, PetscObject obj, PetscInt depth, PetscInt clSize, IS *perm)
3320: {
3321:   const PetscInt *clPerm = NULL;

3323:   PetscFunctionBegin;
3324:   PetscCall(PetscSectionGetClosurePermutation_Private(section, obj, depth, clSize, &clPerm));
3325:   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);
3326:   PetscCall(ISCreateGeneral(PETSC_COMM_SELF, clSize, clPerm, PETSC_USE_POINTER, perm));
3327:   PetscFunctionReturn(PETSC_SUCCESS);
3328: }

3330: PetscErrorCode PetscSectionGetClosureInversePermutation_Internal(PetscSection section, PetscObject obj, PetscInt depth, PetscInt size, const PetscInt *perm[])
3331: {
3332:   PetscFunctionBegin;
3333:   if (section->clObj == obj && section->clHash) {
3334:     PetscSectionClosurePermKey k = {depth, size};
3335:     PetscSectionClosurePermVal v;
3336:     PetscCall(PetscClPermGet(section->clHash, k, &v));
3337:     if (perm) *perm = v.invPerm;
3338:   } else {
3339:     if (perm) *perm = NULL;
3340:   }
3341:   PetscFunctionReturn(PETSC_SUCCESS);
3342: }

3344: /*@
3345:   PetscSectionGetClosureInversePermutation - Get the inverse dof permutation for the closure of each cell in the section, meaning clPerm[oldIndex] = newIndex.

3347:   Not Collective

3349:   Input Parameters:
3350: + section - The `PetscSection`
3351: . obj     - A `PetscObject` which serves as the key for this index (usually a `DM`)
3352: . depth   - Depth stratum on which to obtain closure permutation
3353: - clSize  - Closure size to be permuted (e.g., may vary with element topology and degree)

3355:   Output Parameter:
3356: . perm - The dof closure permutation

3358:   Level: intermediate

3360:   Note:
3361:   The user must destroy the `IS` that is returned.

3363: .seealso: [PetscSection](ch_petscsection), `PetscSection`, `IS`, `PetscSectionSetClosurePermutation()`, `PetscSectionGetClosureIndex()`, `PetscSectionSetClosureIndex()`, `DMPlexCreateClosureIndex()`
3364: @*/
3365: PetscErrorCode PetscSectionGetClosureInversePermutation(PetscSection section, PetscObject obj, PetscInt depth, PetscInt clSize, IS *perm)
3366: {
3367:   const PetscInt *clPerm = NULL;

3369:   PetscFunctionBegin;
3370:   PetscCall(PetscSectionGetClosureInversePermutation_Internal(section, obj, depth, clSize, &clPerm));
3371:   PetscCall(ISCreateGeneral(PETSC_COMM_SELF, clSize, clPerm, PETSC_USE_POINTER, perm));
3372:   PetscFunctionReturn(PETSC_SUCCESS);
3373: }

3375: /*@
3376:   PetscSectionGetField - Get the `PetscSection` associated with a single field

3378:   Input Parameters:
3379: + s     - The `PetscSection`
3380: - field - The field number

3382:   Output Parameter:
3383: . subs - The `PetscSection` for the given field, note the chart of `subs` is not set

3385:   Level: intermediate

3387:   Note:
3388:   Does not increase the reference count of the selected sub-section. There is no matching `PetscSectionRestoreField()`

3390: .seealso: [PetscSection](ch_petscsection), `PetscSection`, `IS`, `PetscSectionSetNumFields()`
3391: @*/
3392: PetscErrorCode PetscSectionGetField(PetscSection s, PetscInt field, PetscSection *subs)
3393: {
3394:   PetscFunctionBegin;
3396:   PetscAssertPointer(subs, 3);
3397:   PetscSectionCheckValidField(field, s->numFields);
3398:   *subs = s->field[field];
3399:   PetscFunctionReturn(PETSC_SUCCESS);
3400: }

3402: PetscClassId      PETSC_SECTION_SYM_CLASSID;
3403: PetscFunctionList PetscSectionSymList = NULL;

3405: /*@
3406:   PetscSectionSymCreate - Creates an empty `PetscSectionSym` object.

3408:   Collective

3410:   Input Parameter:
3411: . comm - the MPI communicator

3413:   Output Parameter:
3414: . sym - pointer to the new set of symmetries

3416:   Level: developer

3418: .seealso: [PetscSection](ch_petscsection), `PetscSection`, `PetscSectionSym`, `PetscSectionSymDestroy()`
3419: @*/
3420: PetscErrorCode PetscSectionSymCreate(MPI_Comm comm, PetscSectionSym *sym)
3421: {
3422:   PetscFunctionBegin;
3423:   PetscAssertPointer(sym, 2);
3424:   PetscCall(ISInitializePackage());

3426:   PetscCall(PetscHeaderCreate(*sym, PETSC_SECTION_SYM_CLASSID, "PetscSectionSym", "Section Symmetry", "IS", comm, PetscSectionSymDestroy, PetscSectionSymView));
3427:   PetscFunctionReturn(PETSC_SUCCESS);
3428: }

3430: /*@
3431:   PetscSectionSymSetType - Builds a `PetscSectionSym`, for a particular implementation.

3433:   Collective

3435:   Input Parameters:
3436: + sym    - The section symmetry object
3437: - method - The name of the section symmetry type

3439:   Level: developer

3441: .seealso: [PetscSection](ch_petscsection), `PetscSectionSym`, `PetscSectionSymType`, `PetscSectionSymGetType()`, `PetscSectionSymCreate()`
3442: @*/
3443: PetscErrorCode PetscSectionSymSetType(PetscSectionSym sym, PetscSectionSymType method)
3444: {
3445:   PetscErrorCode (*r)(PetscSectionSym);
3446:   PetscBool match;

3448:   PetscFunctionBegin;
3450:   PetscCall(PetscObjectTypeCompare((PetscObject)sym, method, &match));
3451:   if (match) PetscFunctionReturn(PETSC_SUCCESS);

3453:   PetscCall(PetscFunctionListFind(PetscSectionSymList, method, &r));
3454:   PetscCheck(r, PetscObjectComm((PetscObject)sym), PETSC_ERR_ARG_UNKNOWN_TYPE, "Unknown PetscSectionSym type: %s", method);
3455:   PetscTryTypeMethod(sym, destroy);
3456:   sym->ops->destroy = NULL;

3458:   PetscCall((*r)(sym));
3459:   PetscCall(PetscObjectChangeTypeName((PetscObject)sym, method));
3460:   PetscFunctionReturn(PETSC_SUCCESS);
3461: }

3463: /*@
3464:   PetscSectionSymGetType - Gets the section symmetry type name (as a string) from the `PetscSectionSym`.

3466:   Not Collective

3468:   Input Parameter:
3469: . sym - The section symmetry

3471:   Output Parameter:
3472: . type - The index set type name

3474:   Level: developer

3476: .seealso: [PetscSection](ch_petscsection), `PetscSectionSym`, `PetscSectionSymType`, `PetscSectionSymSetType()`, `PetscSectionSymCreate()`
3477: @*/
3478: PetscErrorCode PetscSectionSymGetType(PetscSectionSym sym, PetscSectionSymType *type)
3479: {
3480:   PetscFunctionBegin;
3482:   PetscAssertPointer(type, 2);
3483:   *type = ((PetscObject)sym)->type_name;
3484:   PetscFunctionReturn(PETSC_SUCCESS);
3485: }

3487: /*@C
3488:   PetscSectionSymRegister - Registers a new section symmetry implementation

3490:   Not Collective, No Fortran Support

3492:   Input Parameters:
3493: + sname    - The name of a new user-defined creation routine
3494: - function - The creation routine itself

3496:   Level: developer

3498:   Notes:
3499:   `PetscSectionSymRegister()` may be called multiple times to add several user-defined vectors

3501: .seealso: [PetscSection](ch_petscsection), `PetscSectionSym`, `PetscSectionSymType`, `PetscSectionSymCreate()`, `PetscSectionSymSetType()`
3502: @*/
3503: PetscErrorCode PetscSectionSymRegister(const char sname[], PetscErrorCode (*function)(PetscSectionSym))
3504: {
3505:   PetscFunctionBegin;
3506:   PetscCall(ISInitializePackage());
3507:   PetscCall(PetscFunctionListAdd(&PetscSectionSymList, sname, function));
3508:   PetscFunctionReturn(PETSC_SUCCESS);
3509: }

3511: /*@
3512:   PetscSectionSymDestroy - Destroys a section symmetry.

3514:   Collective

3516:   Input Parameter:
3517: . sym - the section symmetry

3519:   Level: developer

3521: .seealso: [PetscSection](ch_petscsection), `PetscSectionSym`, `PetscSectionSymCreate()`
3522: @*/
3523: PetscErrorCode PetscSectionSymDestroy(PetscSectionSym *sym)
3524: {
3525:   SymWorkLink link, next;

3527:   PetscFunctionBegin;
3528:   if (!*sym) PetscFunctionReturn(PETSC_SUCCESS);
3530:   if (--((PetscObject)*sym)->refct > 0) {
3531:     *sym = NULL;
3532:     PetscFunctionReturn(PETSC_SUCCESS);
3533:   }
3534:   PetscTryTypeMethod(*sym, destroy);
3535:   PetscCheck(!(*sym)->workout, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Work array still checked out");
3536:   for (link = (*sym)->workin; link; link = next) {
3537:     PetscInt    **perms = (PetscInt **)link->perms;
3538:     PetscScalar **rots  = (PetscScalar **)link->rots;
3539:     PetscCall(PetscFree2(perms, rots));
3540:     next = link->next;
3541:     PetscCall(PetscFree(link));
3542:   }
3543:   (*sym)->workin = NULL;
3544:   PetscCall(PetscHeaderDestroy(sym));
3545:   PetscFunctionReturn(PETSC_SUCCESS);
3546: }

3548: /*@
3549:   PetscSectionSymView - Displays a section symmetry

3551:   Collective

3553:   Input Parameters:
3554: + sym    - the index set
3555: - viewer - viewer used to display the set, for example `PETSC_VIEWER_STDOUT_SELF`.

3557:   Level: developer

3559: .seealso: `PetscSectionSym`, `PetscViewer`, `PetscViewerASCIIOpen()`
3560: @*/
3561: PetscErrorCode PetscSectionSymView(PetscSectionSym sym, PetscViewer viewer)
3562: {
3563:   PetscFunctionBegin;
3565:   if (!viewer) PetscCall(PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)sym), &viewer));
3567:   PetscCheckSameComm(sym, 1, viewer, 2);
3568:   PetscCall(PetscObjectPrintClassNamePrefixType((PetscObject)sym, viewer));
3569:   PetscTryTypeMethod(sym, view, viewer);
3570:   PetscFunctionReturn(PETSC_SUCCESS);
3571: }

3573: /*@
3574:   PetscSectionSetSym - Set the symmetries for the data referred to by the section

3576:   Collective

3578:   Input Parameters:
3579: + section - the section describing data layout
3580: - sym     - the symmetry describing the affect of orientation on the access of the data

3582:   Level: developer

3584: .seealso: [PetscSection](ch_petscsection), `PetscSectionSym`, `PetscSectionGetSym()`, `PetscSectionSymCreate()`
3585: @*/
3586: PetscErrorCode PetscSectionSetSym(PetscSection section, PetscSectionSym sym)
3587: {
3588:   PetscFunctionBegin;
3590:   PetscCall(PetscSectionSymDestroy(&section->sym));
3591:   if (sym) {
3593:     PetscCheckSameComm(section, 1, sym, 2);
3594:     PetscCall(PetscObjectReference((PetscObject)sym));
3595:   }
3596:   section->sym = sym;
3597:   PetscFunctionReturn(PETSC_SUCCESS);
3598: }

3600: /*@
3601:   PetscSectionGetSym - Get the symmetries for the data referred to by the section

3603:   Not Collective

3605:   Input Parameter:
3606: . section - the section describing data layout

3608:   Output Parameter:
3609: . sym - the symmetry describing the affect of orientation on the access of the data, provided previously by `PetscSectionSetSym()`

3611:   Level: developer

3613: .seealso: [PetscSection](ch_petscsection), `PetscSectionSym`, `PetscSectionSetSym()`, `PetscSectionSymCreate()`
3614: @*/
3615: PetscErrorCode PetscSectionGetSym(PetscSection section, PetscSectionSym *sym)
3616: {
3617:   PetscFunctionBegin;
3619:   *sym = section->sym;
3620:   PetscFunctionReturn(PETSC_SUCCESS);
3621: }

3623: /*@
3624:   PetscSectionSetFieldSym - Set the symmetries for the data referred to by a field of the section

3626:   Collective

3628:   Input Parameters:
3629: + section - the section describing data layout
3630: . field   - the field number
3631: - sym     - the symmetry describing the affect of orientation on the access of the data

3633:   Level: developer

3635: .seealso: [PetscSection](ch_petscsection), `PetscSectionSym`, `PetscSectionGetFieldSym()`, `PetscSectionSymCreate()`
3636: @*/
3637: PetscErrorCode PetscSectionSetFieldSym(PetscSection section, PetscInt field, PetscSectionSym sym)
3638: {
3639:   PetscFunctionBegin;
3641:   PetscSectionCheckValidField(field, section->numFields);
3642:   PetscCall(PetscSectionSetSym(section->field[field], sym));
3643:   PetscFunctionReturn(PETSC_SUCCESS);
3644: }

3646: /*@
3647:   PetscSectionGetFieldSym - Get the symmetries for the data referred to by a field of the section

3649:   Collective

3651:   Input Parameters:
3652: + section - the section describing data layout
3653: - field   - the field number

3655:   Output Parameter:
3656: . sym - the symmetry describing the affect of orientation on the access of the data

3658:   Level: developer

3660: .seealso: [PetscSection](ch_petscsection), `PetscSectionSym`, `PetscSectionSetFieldSym()`, `PetscSectionSymCreate()`
3661: @*/
3662: PetscErrorCode PetscSectionGetFieldSym(PetscSection section, PetscInt field, PetscSectionSym *sym)
3663: {
3664:   PetscFunctionBegin;
3666:   PetscSectionCheckValidField(field, section->numFields);
3667:   *sym = section->field[field]->sym;
3668:   PetscFunctionReturn(PETSC_SUCCESS);
3669: }

3671: /*@C
3672:   PetscSectionGetPointSyms - Get the symmetries for a set of points in a `PetscSection` under specific orientations.

3674:   Not Collective

3676:   Input Parameters:
3677: + section   - the section
3678: . numPoints - the number of points
3679: - points    - an array of size 2 * `numPoints`, containing a list of (point, orientation) pairs. (An orientation is an
3680:               arbitrary integer: its interpretation is up to sym.  Orientations are used by `DM`: for their interpretation in that
3681:               context, see `DMPlexGetConeOrientation()`).

3683:   Output Parameters:
3684: + perms - The permutations for the given orientations (or `NULL` if there is no symmetry or the permutation is the identity).
3685: - rots  - The field rotations symmetries for the given orientations (or `NULL` if there is no symmetry or the rotations are all
3686:     identity).

3688:   Example of usage, gathering dofs into a local array (lArray) from a section array (sArray):
3689: .vb
3690:      const PetscInt    **perms;
3691:      const PetscScalar **rots;
3692:      PetscInt            lOffset;

3694:      PetscSectionGetPointSyms(section,numPoints,points,&perms,&rots);
3695:      for (i = 0, lOffset = 0; i < numPoints; i++) {
3696:        PetscInt           point = points[2*i], dof, sOffset;
3697:        const PetscInt    *perm  = perms ? perms[i] : NULL;
3698:        const PetscScalar *rot   = rots  ? rots[i]  : NULL;

3700:        PetscSectionGetDof(section,point,&dof);
3701:        PetscSectionGetOffset(section,point,&sOffset);

3703:        if (perm) { for (j = 0; j < dof; j++) lArray[lOffset + perm[j]]  = sArray[sOffset + j]; }
3704:        else      { for (j = 0; j < dof; j++) lArray[lOffset +      j ]  = sArray[sOffset + j]; }
3705:        if (rot)  { for (j = 0; j < dof; j++) lArray[lOffset +      j ] *= rot[j];              }
3706:        lOffset += dof;
3707:      }
3708:      PetscSectionRestorePointSyms(section,numPoints,points,&perms,&rots);
3709: .ve

3711:   Example of usage, adding dofs into a section array (sArray) from a local array (lArray):
3712: .vb
3713:      const PetscInt    **perms;
3714:      const PetscScalar **rots;
3715:      PetscInt            lOffset;

3717:      PetscSectionGetPointSyms(section,numPoints,points,&perms,&rots);
3718:      for (i = 0, lOffset = 0; i < numPoints; i++) {
3719:        PetscInt           point = points[2*i], dof, sOffset;
3720:        const PetscInt    *perm  = perms ? perms[i] : NULL;
3721:        const PetscScalar *rot   = rots  ? rots[i]  : NULL;

3723:        PetscSectionGetDof(section,point,&dof);
3724:        PetscSectionGetOffset(section,point,&sOff);

3726:        if (perm) { for (j = 0; j < dof; j++) sArray[sOffset + j] += lArray[lOffset + perm[j]] * (rot ? PetscConj(rot[perm[j]]) : 1.); }
3727:        else      { for (j = 0; j < dof; j++) sArray[sOffset + j] += lArray[lOffset +      j ] * (rot ? PetscConj(rot[     j ]) : 1.); }
3728:        offset += dof;
3729:      }
3730:      PetscSectionRestorePointSyms(section,numPoints,points,&perms,&rots);
3731: .ve

3733:   Level: developer

3735:   Notes:
3736:   `PetscSectionSetSym()` must have been previously called to provide the symmetries to the `PetscSection`

3738:   Use `PetscSectionRestorePointSyms()` when finished with the data

3740: .seealso: [PetscSection](ch_petscsection), `PetscSectionSym`, `PetscSectionRestorePointSyms()`, `PetscSectionSymCreate()`, `PetscSectionSetSym()`, `PetscSectionGetSym()`
3741: @*/
3742: PetscErrorCode PetscSectionGetPointSyms(PetscSection section, PetscInt numPoints, const PetscInt *points, const PetscInt ***perms, const PetscScalar ***rots)
3743: {
3744:   PetscSectionSym sym;

3746:   PetscFunctionBegin;
3748:   if (numPoints) PetscAssertPointer(points, 3);
3749:   if (perms) *perms = NULL;
3750:   if (rots) *rots = NULL;
3751:   sym = section->sym;
3752:   if (sym && (perms || rots)) {
3753:     SymWorkLink link;

3755:     if (sym->workin) {
3756:       link        = sym->workin;
3757:       sym->workin = sym->workin->next;
3758:     } else {
3759:       PetscCall(PetscNew(&link));
3760:     }
3761:     if (numPoints > link->numPoints) {
3762:       PetscInt    **perms = (PetscInt **)link->perms;
3763:       PetscScalar **rots  = (PetscScalar **)link->rots;
3764:       PetscCall(PetscFree2(perms, rots));
3765:       PetscCall(PetscMalloc2(numPoints, (PetscInt ***)&link->perms, numPoints, (PetscScalar ***)&link->rots));
3766:       link->numPoints = numPoints;
3767:     }
3768:     link->next   = sym->workout;
3769:     sym->workout = link;
3770:     PetscCall(PetscArrayzero((PetscInt **)link->perms, numPoints));
3771:     PetscCall(PetscArrayzero((PetscInt **)link->rots, numPoints));
3772:     PetscUseTypeMethod(sym, getpoints, section, numPoints, points, link->perms, link->rots);
3773:     if (perms) *perms = link->perms;
3774:     if (rots) *rots = link->rots;
3775:   }
3776:   PetscFunctionReturn(PETSC_SUCCESS);
3777: }

3779: /*@C
3780:   PetscSectionRestorePointSyms - Restore the symmetries returned by `PetscSectionGetPointSyms()`

3782:   Not Collective

3784:   Input Parameters:
3785: + section   - the section
3786: . numPoints - the number of points
3787: . points    - an array of size 2 * `numPoints`, containing a list of (point, orientation) pairs. (An orientation is an
3788:               arbitrary integer: its interpretation is up to sym.  Orientations are used by `DM`: for their interpretation in that
3789:               context, see `DMPlexGetConeOrientation()`).
3790: . perms     - The permutations for the given orientations: set to `NULL` at conclusion
3791: - rots      - The field rotations symmetries for the given orientations: set to `NULL` at conclusion

3793:   Level: developer

3795: .seealso: [PetscSection](ch_petscsection), `PetscSectionSym`, `PetscSectionGetPointSyms()`, `PetscSectionSymCreate()`, `PetscSectionSetSym()`, `PetscSectionGetSym()`
3796: @*/
3797: PetscErrorCode PetscSectionRestorePointSyms(PetscSection section, PetscInt numPoints, const PetscInt *points, const PetscInt ***perms, const PetscScalar ***rots)
3798: {
3799:   PetscSectionSym sym;

3801:   PetscFunctionBegin;
3803:   sym = section->sym;
3804:   if (sym && (perms || rots)) {
3805:     SymWorkLink *p, link;

3807:     for (p = &sym->workout; (link = *p); p = &link->next) {
3808:       if ((perms && link->perms == *perms) || (rots && link->rots == *rots)) {
3809:         *p          = link->next;
3810:         link->next  = sym->workin;
3811:         sym->workin = link;
3812:         if (perms) *perms = NULL;
3813:         if (rots) *rots = NULL;
3814:         PetscFunctionReturn(PETSC_SUCCESS);
3815:       }
3816:     }
3817:     SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Array was not checked out");
3818:   }
3819:   PetscFunctionReturn(PETSC_SUCCESS);
3820: }

3822: /*@C
3823:   PetscSectionGetFieldPointSyms - Get the symmetries for a set of points in a field of a `PetscSection` under specific orientations.

3825:   Not Collective

3827:   Input Parameters:
3828: + section   - the section
3829: . field     - the field of the section
3830: . numPoints - the number of points
3831: - points    - an array of size 2 * `numPoints`, containing a list of (point, orientation) pairs. (An orientation is an
3832:     arbitrary integer: its interpretation is up to sym.  Orientations are used by `DM`: for their interpretation in that
3833:     context, see `DMPlexGetConeOrientation()`).

3835:   Output Parameters:
3836: + perms - The permutations for the given orientations (or `NULL` if there is no symmetry or the permutation is the identity).
3837: - rots  - The field rotations symmetries for the given orientations (or `NULL` if there is no symmetry or the rotations are all
3838:     identity).

3840:   Level: developer

3842:   Notes:
3843:   `PetscSectionSetFieldSym()` must have been previously called to provide the symmetries to the `PetscSection`

3845:   Use `PetscSectionRestoreFieldPointSyms()` when finished with the data

3847: .seealso: [PetscSection](ch_petscsection), `PetscSectionSym`, `PetscSectionGetPointSyms()`, `PetscSectionRestoreFieldPointSyms()`
3848: @*/
3849: PetscErrorCode PetscSectionGetFieldPointSyms(PetscSection section, PetscInt field, PetscInt numPoints, const PetscInt *points, const PetscInt ***perms, const PetscScalar ***rots)
3850: {
3851:   PetscFunctionBegin;
3853:   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);
3854:   PetscCall(PetscSectionGetPointSyms(section->field[field], numPoints, points, perms, rots));
3855:   PetscFunctionReturn(PETSC_SUCCESS);
3856: }

3858: /*@C
3859:   PetscSectionRestoreFieldPointSyms - Restore the symmetries returned by `PetscSectionGetFieldPointSyms()`

3861:   Not Collective

3863:   Input Parameters:
3864: + section   - the section
3865: . field     - the field number
3866: . numPoints - the number of points
3867: . points    - an array of size 2 * `numPoints`, containing a list of (point, orientation) pairs. (An orientation is an
3868:     arbitrary integer: its interpretation is up to sym.  Orientations are used by `DM`: for their interpretation in that
3869:     context, see `DMPlexGetConeOrientation()`).
3870: . perms     - The permutations for the given orientations: set to NULL at conclusion
3871: - rots      - The field rotations symmetries for the given orientations: set to NULL at conclusion

3873:   Level: developer

3875: .seealso: [PetscSection](ch_petscsection), `PetscSectionSym`, `PetscSectionRestorePointSyms()`, `petscSectionGetFieldPointSyms()`, `PetscSectionSymCreate()`, `PetscSectionSetSym()`, `PetscSectionGetSym()`
3876: @*/
3877: PetscErrorCode PetscSectionRestoreFieldPointSyms(PetscSection section, PetscInt field, PetscInt numPoints, const PetscInt *points, const PetscInt ***perms, const PetscScalar ***rots)
3878: {
3879:   PetscFunctionBegin;
3881:   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);
3882:   PetscCall(PetscSectionRestorePointSyms(section->field[field], numPoints, points, perms, rots));
3883:   PetscFunctionReturn(PETSC_SUCCESS);
3884: }

3886: /*@
3887:   PetscSectionSymCopy - Copy the symmetries, assuming that the point structure is compatible

3889:   Not Collective

3891:   Input Parameter:
3892: . sym - the `PetscSectionSym`

3894:   Output Parameter:
3895: . nsym - the equivalent symmetries

3897:   Level: developer

3899: .seealso: [PetscSection](ch_petscsection), `PetscSectionSym`, `PetscSectionSymCreate()`, `PetscSectionSetSym()`, `PetscSectionGetSym()`, `PetscSectionSymLabelSetStratum()`, `PetscSectionGetPointSyms()`
3900: @*/
3901: PetscErrorCode PetscSectionSymCopy(PetscSectionSym sym, PetscSectionSym nsym)
3902: {
3903:   PetscFunctionBegin;
3906:   PetscTryTypeMethod(sym, copy, nsym);
3907:   PetscFunctionReturn(PETSC_SUCCESS);
3908: }

3910: /*@
3911:   PetscSectionSymDistribute - Distribute the symmetries in accordance with the input `PetscSF`

3913:   Collective

3915:   Input Parameters:
3916: + sym         - the `PetscSectionSym`
3917: - migrationSF - the distribution map from roots to leaves

3919:   Output Parameter:
3920: . dsym - the redistributed symmetries

3922:   Level: developer

3924: .seealso: [PetscSection](ch_petscsection), `PetscSectionSym`, `PetscSectionSymCreate()`, `PetscSectionSetSym()`, `PetscSectionGetSym()`, `PetscSectionSymLabelSetStratum()`, `PetscSectionGetPointSyms()`
3925: @*/
3926: PetscErrorCode PetscSectionSymDistribute(PetscSectionSym sym, PetscSF migrationSF, PetscSectionSym *dsym)
3927: {
3928:   PetscFunctionBegin;
3931:   PetscAssertPointer(dsym, 3);
3932:   PetscTryTypeMethod(sym, distribute, migrationSF, dsym);
3933:   PetscFunctionReturn(PETSC_SUCCESS);
3934: }

3936: /*@
3937:   PetscSectionGetUseFieldOffsets - Get the flag indicating if field offsets are used directly in a global section, rather than just the point offset

3939:   Not Collective

3941:   Input Parameter:
3942: . s - the global `PetscSection`

3944:   Output Parameter:
3945: . flg - the flag

3947:   Level: developer

3949: .seealso: [PetscSection](ch_petscsection), `PetscSectionSym`, `PetscSectionSetChart()`, `PetscSectionCreate()`
3950: @*/
3951: PetscErrorCode PetscSectionGetUseFieldOffsets(PetscSection s, PetscBool *flg)
3952: {
3953:   PetscFunctionBegin;
3955:   *flg = s->useFieldOff;
3956:   PetscFunctionReturn(PETSC_SUCCESS);
3957: }

3959: /*@
3960:   PetscSectionSetUseFieldOffsets - Set the flag to use field offsets directly in a global section, rather than just the point offset

3962:   Not Collective

3964:   Input Parameters:
3965: + s   - the global `PetscSection`
3966: - flg - the flag

3968:   Level: developer

3970: .seealso: [PetscSection](ch_petscsection), `PetscSectionSym`, `PetscSectionGetUseFieldOffsets()`, `PetscSectionSetChart()`, `PetscSectionCreate()`
3971: @*/
3972: PetscErrorCode PetscSectionSetUseFieldOffsets(PetscSection s, PetscBool flg)
3973: {
3974:   PetscFunctionBegin;
3976:   s->useFieldOff = flg;
3977:   PetscFunctionReturn(PETSC_SUCCESS);
3978: }

3980: #define PetscSectionExpandPoints_Loop(TYPE) \
3981:   do { \
3982:     PetscInt i, n, o0, o1, size; \
3983:     TYPE    *a0 = (TYPE *)origArray, *a1; \
3984:     PetscCall(PetscSectionGetStorageSize(s, &size)); \
3985:     PetscCall(PetscMalloc1(size, &a1)); \
3986:     for (i = 0; i < npoints; i++) { \
3987:       PetscCall(PetscSectionGetOffset(origSection, points_[i], &o0)); \
3988:       PetscCall(PetscSectionGetOffset(s, i, &o1)); \
3989:       PetscCall(PetscSectionGetDof(s, i, &n)); \
3990:       PetscCall(PetscMemcpy(&a1[o1], &a0[o0], n * unitsize)); \
3991:     } \
3992:     *newArray = (void *)a1; \
3993:   } while (0)

3995: /*@
3996:   PetscSectionExtractDofsFromArray - Extracts elements of an array corresponding to DOFs of specified points.

3998:   Not Collective

4000:   Input Parameters:
4001: + origSection - the `PetscSection` describing the layout of the array
4002: . dataType    - `MPI_Datatype` describing the data type of the array (currently only `MPIU_INT`, `MPIU_SCALAR`, `MPIU_REAL`)
4003: . origArray   - the array; its size must be equal to the storage size of `origSection`
4004: - points      - `IS` with points to extract; its indices must lie in the chart of `origSection`

4006:   Output Parameters:
4007: + newSection - the new `PetscSection` describing the layout of the new array (with points renumbered 0,1,... but preserving numbers of DOFs)
4008: - newArray   - the array of the extracted DOFs; its size is the storage size of `newSection`

4010:   Level: developer

4012: .seealso: [PetscSection](ch_petscsection), `PetscSectionSym`, `PetscSectionGetChart()`, `PetscSectionGetDof()`, `PetscSectionGetStorageSize()`, `PetscSectionCreate()`
4013: @*/
4014: PetscErrorCode PetscSectionExtractDofsFromArray(PetscSection origSection, MPI_Datatype dataType, const void *origArray, IS points, PetscSection *newSection, void *newArray[])
4015: {
4016:   PetscSection    s;
4017:   const PetscInt *points_;
4018:   PetscInt        i, n, npoints, pStart, pEnd;
4019:   PetscMPIInt     unitsize;

4021:   PetscFunctionBegin;
4023:   PetscAssertPointer(origArray, 3);
4025:   if (newSection) PetscAssertPointer(newSection, 5);
4026:   if (newArray) PetscAssertPointer(newArray, 6);
4027:   PetscCallMPI(MPI_Type_size(dataType, &unitsize));
4028:   PetscCall(ISGetLocalSize(points, &npoints));
4029:   PetscCall(ISGetIndices(points, &points_));
4030:   PetscCall(PetscSectionGetChart(origSection, &pStart, &pEnd));
4031:   PetscCall(PetscSectionCreate(PETSC_COMM_SELF, &s));
4032:   PetscCall(PetscSectionSetChart(s, 0, npoints));
4033:   for (i = 0; i < npoints; i++) {
4034:     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);
4035:     PetscCall(PetscSectionGetDof(origSection, points_[i], &n));
4036:     PetscCall(PetscSectionSetDof(s, i, n));
4037:   }
4038:   PetscCall(PetscSectionSetUp(s));
4039:   if (newArray) {
4040:     if (dataType == MPIU_INT) {
4041:       PetscSectionExpandPoints_Loop(PetscInt);
4042:     } else if (dataType == MPIU_SCALAR) {
4043:       PetscSectionExpandPoints_Loop(PetscScalar);
4044:     } else if (dataType == MPIU_REAL) {
4045:       PetscSectionExpandPoints_Loop(PetscReal);
4046:     } else SETERRQ(PETSC_COMM_SELF, PETSC_ERR_SUP, "not implemented for this MPI_Datatype");
4047:   }
4048:   if (newSection) {
4049:     *newSection = s;
4050:   } else {
4051:     PetscCall(PetscSectionDestroy(&s));
4052:   }
4053:   PetscCall(ISRestoreIndices(points, &points_));
4054:   PetscFunctionReturn(PETSC_SUCCESS);
4055: }

4057: /*@
4058:   PetscSectionMigrateData - Migrate data described by a `PetscSection` using a `PetscSF` that defines a original-to-new (root-to-leaf) point mapping

4060:   Collective

4062:   Input Parameters:
4063: + migratePointSF - defines the mapping (communication) of the root points to the leaf points
4064: . datatype       - the type of data
4065: . rootSection    - the `PetscSection` that describes the data layout on the root points (how many dof and what fields are associated with each root point)
4066: - rootData       - the existing data array described by `rootSection`, may be `NULL` is storage size of `rootSection` is zero

4068:   Output Parameters:
4069: + leafSection   - the new `PetscSection` that describes the data layout on the leaf points
4070: . leafData      - the redistributed data array that is associated with the leaf points
4071: - migrateDataSF - defines the mapping (communication) of the `rootData` array to the `leafData` array, may be `NULL` if not needed

4073:   Level: advanced

4075:   Notes:
4076:   This function can best be thought of as applying `PetscSFBcastBegin()` to an array described by a `PetscSection`.
4077:   While `PetscSFBcastBegin()` is limited to broadcasting data that is of the same size for every index, this function allows the data to be a different size for each index.
4078:   The size and layout of that irregularly sized data before and after `PetscSFBcastBegin()` is described by the `rootSection` and `leafSection`, respectively.

4080:   This function combines `PetscSFDistributeSection()`, `PetscSFCreateSectionSF()`, and `PetscSFBcastBegin()`/`PetscSFBcastEnd()` into a single call.
4081:   `migrateDataSF` can be used to repeat the `PetscSFBcastBegin()`/`PetscSFBcastEnd()` on a different data array described by the same `rootSection`.

4083:   This should not be used for global-to-local type communication patterns.
4084:   For this use case, see `PetscSectionCreateGlobalSection()` and `PetscSFSetGraphSection()`.

4086: .seealso: [PetscSection](ch_petscsection), `PetscSection`, `PetscSFDistributeSection()`, `PetscSFCreateSectionSF()`, `DMPlexDistributeData()`
4087: @*/
4088: PetscErrorCode PetscSectionMigrateData(PetscSF migratePointSF, MPI_Datatype datatype, PetscSection rootSection, const void *rootData, PetscSection leafSection, void *leafData[], PetscSF *migrateDataSF)
4089: {
4090:   PetscSF     fieldSF;
4091:   PetscInt   *remoteOffsets, fieldSize;
4092:   PetscMPIInt dataSize;

4094:   PetscFunctionBegin;
4097:   if (rootData) PetscAssertPointer(rootData, 4);
4098:   else {
4099:     PetscInt size;
4100:     PetscCall(PetscSectionGetStorageSize(rootSection, &size));
4101:     PetscCheck(size == 0, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "originalData may be NULL iff the storage size of originalSection is zero, but is %" PetscInt_FMT, size);
4102:   }
4104:   PetscAssertPointer(leafData, 6);
4105:   if (migrateDataSF) PetscAssertPointer(migrateDataSF, 7);

4107:   PetscCall(PetscSFDistributeSection(migratePointSF, rootSection, &remoteOffsets, leafSection));
4108:   PetscCall(PetscSFCreateSectionSF(migratePointSF, rootSection, remoteOffsets, leafSection, &fieldSF));
4109:   PetscCall(PetscFree(remoteOffsets));

4111:   PetscCall(PetscSectionGetStorageSize(leafSection, &fieldSize));
4112:   PetscCallMPI(MPI_Type_size(datatype, &dataSize));
4113:   PetscCall(PetscMalloc(fieldSize * dataSize, leafData));
4114:   PetscCall(PetscSFBcastBegin(fieldSF, datatype, rootData, *leafData, MPI_REPLACE));
4115:   PetscCall(PetscSFBcastEnd(fieldSF, datatype, rootData, *leafData, MPI_REPLACE));

4117:   if (migrateDataSF) *migrateDataSF = fieldSF;
4118:   else PetscCall(PetscSFDestroy(&fieldSF));
4119:   PetscFunctionReturn(PETSC_SUCCESS);
4120: }