Actual source code: dmi.c
1: #include <petsc/private/dmimpl.h>
2: #include <petscds.h>
4: // Greatest common divisor of two nonnegative integers
5: PetscInt PetscGCD(PetscInt a, PetscInt b)
6: {
7: while (b != 0) {
8: PetscInt tmp = b;
9: b = a % b;
10: a = tmp;
11: }
12: return a;
13: }
15: PetscErrorCode DMCreateGlobalVector_Section_Private(DM dm, Vec *vec)
16: {
17: PetscSection gSection;
18: PetscInt localSize, bs, blockSize = -1, pStart, pEnd, p;
19: PetscInt in[2], out[2];
21: PetscFunctionBegin;
22: PetscCall(DMGetGlobalSection(dm, &gSection));
23: PetscCall(PetscSectionGetChart(gSection, &pStart, &pEnd));
24: for (p = pStart; p < pEnd; ++p) {
25: PetscInt dof, cdof;
27: PetscCall(PetscSectionGetDof(gSection, p, &dof));
28: PetscCall(PetscSectionGetConstraintDof(gSection, p, &cdof));
30: if (dof - cdof > 0) {
31: if (blockSize < 0) {
32: /* set blockSize */
33: blockSize = dof - cdof;
34: } else {
35: blockSize = PetscGCD(dof - cdof, blockSize);
36: }
37: }
38: }
40: in[0] = blockSize < 0 ? PETSC_MIN_INT : -blockSize;
41: in[1] = blockSize;
42: PetscCall(MPIU_Allreduce(in, out, 2, MPIU_INT, MPI_MAX, PetscObjectComm((PetscObject)dm)));
43: /* -out[0] = min(blockSize), out[1] = max(blockSize) */
44: if (-out[0] == out[1]) {
45: bs = out[1];
46: } else bs = 1;
48: if (bs < 0) { /* Everyone was empty */
49: blockSize = 1;
50: bs = 1;
51: }
53: PetscCall(PetscSectionGetConstrainedStorageSize(gSection, &localSize));
54: PetscCheck(localSize % blockSize == 0, PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_WRONG, "Mismatch between blocksize %" PetscInt_FMT " and local storage size %" PetscInt_FMT, blockSize, localSize);
55: PetscCall(VecCreate(PetscObjectComm((PetscObject)dm), vec));
56: PetscCall(VecSetSizes(*vec, localSize, PETSC_DETERMINE));
57: PetscCall(VecSetBlockSize(*vec, bs));
58: PetscCall(VecSetType(*vec, dm->vectype));
59: PetscCall(VecSetDM(*vec, dm));
60: /* PetscCall(VecSetLocalToGlobalMapping(*vec, dm->ltogmap)); */
61: PetscFunctionReturn(PETSC_SUCCESS);
62: }
64: PetscErrorCode DMCreateLocalVector_Section_Private(DM dm, Vec *vec)
65: {
66: PetscSection section;
67: PetscInt localSize, blockSize = -1, pStart, pEnd, p;
69: PetscFunctionBegin;
70: PetscCall(DMGetLocalSection(dm, §ion));
71: PetscCall(PetscSectionGetChart(section, &pStart, &pEnd));
72: for (p = pStart; p < pEnd; ++p) {
73: PetscInt dof;
75: PetscCall(PetscSectionGetDof(section, p, &dof));
76: if ((blockSize < 0) && (dof > 0)) blockSize = dof;
77: if (dof > 0) blockSize = PetscGCD(dof, blockSize);
78: }
79: PetscCall(PetscSectionGetStorageSize(section, &localSize));
80: PetscCall(VecCreate(PETSC_COMM_SELF, vec));
81: PetscCall(VecSetSizes(*vec, localSize, localSize));
82: PetscCall(VecSetBlockSize(*vec, blockSize));
83: PetscCall(VecSetType(*vec, dm->vectype));
84: PetscCall(VecSetDM(*vec, dm));
85: PetscFunctionReturn(PETSC_SUCCESS);
86: }
88: static PetscErrorCode PetscSectionSelectFields_Private(PetscSection s, PetscSection gs, PetscInt numFields, const PetscInt fields[], const PetscInt numComps[], const PetscInt comps[], IS *is)
89: {
90: PetscInt *subIndices;
91: PetscInt bs = 0, bsLocal[2], bsMinMax[2];
92: PetscInt pStart, pEnd, Nc, subSize = 0, subOff = 0;
94: PetscFunctionBegin;
95: PetscCall(PetscSectionGetChart(gs, &pStart, &pEnd));
96: if (numComps) {
97: for (PetscInt f = 0, off = 0; f < numFields; ++f) {
98: PetscInt Nc;
100: if (numComps[f] < 0) continue;
101: PetscCall(PetscSectionGetFieldComponents(s, f, &Nc));
102: PetscCheck(numComps[f] <= Nc, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Field %" PetscInt_FMT ": Number of selected components %" PetscInt_FMT " > %" PetscInt_FMT " number of field components", f, numComps[f], Nc);
103: for (PetscInt c = 0; c < numComps[f]; ++c, ++off) PetscCheck(comps[off] < Nc, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Field %" PetscInt_FMT ": component %" PetscInt_FMT " not in [0, %" PetscInt_FMT ")", f, comps[off], Nc);
104: bs += numComps[f];
105: }
106: } else {
107: for (PetscInt f = 0; f < numFields; ++f) {
108: PetscInt Nc;
110: PetscCall(PetscSectionGetFieldComponents(s, fields[f], &Nc));
111: bs += Nc;
112: }
113: }
114: for (PetscInt p = pStart; p < pEnd; ++p) {
115: PetscInt gdof, pSubSize = 0;
117: PetscCall(PetscSectionGetDof(gs, p, &gdof));
118: if (gdof > 0) {
119: PetscInt off = 0;
121: for (PetscInt f = 0; f < numFields; ++f) {
122: PetscInt fdof, fcdof, sfdof, sfcdof = 0;
124: PetscCall(PetscSectionGetFieldComponents(s, f, &Nc));
125: PetscCall(PetscSectionGetFieldDof(s, p, fields[f], &fdof));
126: PetscCall(PetscSectionGetFieldConstraintDof(s, p, fields[f], &fcdof));
127: if (numComps && numComps[f] >= 0) {
128: const PetscInt *ind;
130: // Assume sets of dofs on points are of size Nc
131: PetscCheck(!(fdof % Nc), PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Number of components %" PetscInt_FMT " should evenly divide the dofs %" PetscInt_FMT " on point %" PetscInt_FMT, Nc, fdof, p);
132: sfdof = (fdof / Nc) * numComps[f];
133: PetscCall(PetscSectionGetFieldConstraintIndices(s, p, fields[f], &ind));
134: for (PetscInt i = 0; i < (fdof / Nc); ++i) {
135: for (PetscInt c = 0, fcc = 0; c < Nc; ++c) {
136: if (c == comps[off + fcc]) {
137: ++fcc;
138: ++sfcdof;
139: }
140: }
141: }
142: pSubSize += sfdof - sfcdof;
143: off += numComps[f];
144: } else {
145: pSubSize += fdof - fcdof;
146: }
147: }
148: subSize += pSubSize;
149: if (pSubSize && bs != pSubSize) {
150: // Layout does not admit a pointwise block size
151: bs = 1;
152: }
153: }
154: }
155: // Must have same blocksize on all procs (some might have no points)
156: bsLocal[0] = bs < 0 ? PETSC_MAX_INT : bs;
157: bsLocal[1] = bs;
158: PetscCall(PetscGlobalMinMaxInt(PetscObjectComm((PetscObject)gs), bsLocal, bsMinMax));
159: if (bsMinMax[0] != bsMinMax[1]) {
160: bs = 1;
161: } else {
162: bs = bsMinMax[0];
163: }
164: PetscCall(PetscMalloc1(subSize, &subIndices));
165: for (PetscInt p = pStart; p < pEnd; ++p) {
166: PetscInt gdof, goff;
168: PetscCall(PetscSectionGetDof(gs, p, &gdof));
169: if (gdof > 0) {
170: PetscInt off = 0;
172: PetscCall(PetscSectionGetOffset(gs, p, &goff));
173: for (PetscInt f = 0; f < numFields; ++f) {
174: PetscInt fdof, fcdof, poff = 0;
176: /* Can get rid of this loop by storing field information in the global section */
177: for (PetscInt f2 = 0; f2 < fields[f]; ++f2) {
178: PetscCall(PetscSectionGetFieldDof(s, p, f2, &fdof));
179: PetscCall(PetscSectionGetFieldConstraintDof(s, p, f2, &fcdof));
180: poff += fdof - fcdof;
181: }
182: PetscCall(PetscSectionGetFieldDof(s, p, fields[f], &fdof));
183: PetscCall(PetscSectionGetFieldConstraintDof(s, p, fields[f], &fcdof));
185: if (numComps && numComps[f] >= 0) {
186: const PetscInt *ind;
188: // Assume sets of dofs on points are of size Nc
189: PetscCall(PetscSectionGetFieldConstraintIndices(s, p, fields[f], &ind));
190: for (PetscInt i = 0, fcoff = 0, pfoff = 0; i < (fdof / Nc); ++i) {
191: for (PetscInt c = 0, fcc = 0; c < Nc; ++c) {
192: const PetscInt k = i * Nc + c;
194: if (ind[fcoff] == k) {
195: ++fcoff;
196: continue;
197: }
198: if (c == comps[off + fcc]) {
199: ++fcc;
200: subIndices[subOff++] = goff + poff + pfoff;
201: }
202: ++pfoff;
203: }
204: }
205: off += numComps[f];
206: } else {
207: for (PetscInt fc = 0; fc < fdof - fcdof; ++fc, ++subOff) subIndices[subOff] = goff + poff + fc;
208: }
209: }
210: }
211: }
212: PetscCheck(subSize == subOff, PETSC_COMM_SELF, PETSC_ERR_ARG_INCOMP, "The offset array size %" PetscInt_FMT " != %" PetscInt_FMT " the number of indices", subSize, subOff);
213: PetscCall(ISCreateGeneral(PetscObjectComm((PetscObject)gs), subSize, subIndices, PETSC_OWN_POINTER, is));
214: if (bs > 1) {
215: // We need to check that the block size does not come from non-contiguous fields
216: PetscInt set = 1, rset = 1;
217: for (PetscInt i = 0; i < subSize; i += bs) {
218: for (PetscInt j = 0; j < bs; ++j) {
219: if (subIndices[i + j] != subIndices[i] + j) {
220: set = 0;
221: break;
222: }
223: }
224: }
225: PetscCall(MPIU_Allreduce(&set, &rset, 1, MPIU_INT, MPI_PROD, PetscObjectComm((PetscObject)gs)));
226: if (rset) PetscCall(ISSetBlockSize(*is, bs));
227: }
228: PetscFunctionReturn(PETSC_SUCCESS);
229: }
231: static PetscErrorCode DMSelectFields_Private(DM dm, PetscSection section, PetscInt numFields, const PetscInt fields[], const PetscInt numComps[], const PetscInt comps[], IS *is, DM *subdm)
232: {
233: PetscSection subsection;
234: PetscBool haveNull = PETSC_FALSE;
235: PetscInt nf = 0, of = 0;
237: PetscFunctionBegin;
238: if (numComps) {
239: const PetscInt field = fields[0];
241: PetscCheck(numFields == 1, PETSC_COMM_SELF, PETSC_ERR_SUP, "We only support a single field for component selection right now");
242: PetscCall(PetscSectionCreateComponentSubsection(section, numComps[field], comps, &subsection));
243: PetscCall(DMSetLocalSection(*subdm, subsection));
244: PetscCall(PetscSectionDestroy(&subsection));
245: (*subdm)->nullspaceConstructors[field] = dm->nullspaceConstructors[field];
246: if (dm->probs) {
247: PetscFV fv, fvNew;
248: PetscInt fnum[1] = {field};
250: PetscCall(DMSetNumFields(*subdm, 1));
251: PetscCall(DMGetField(dm, field, NULL, (PetscObject *)&fv));
252: PetscCall(PetscFVClone(fv, &fvNew));
253: PetscCall(PetscFVSetNumComponents(fvNew, numComps[0]));
254: PetscCall(DMSetField(*subdm, 0, NULL, (PetscObject)fvNew));
255: PetscCall(PetscFVDestroy(&fvNew));
256: PetscCall(DMCreateDS(*subdm));
257: if (numComps[0] == 1 && is) {
258: PetscObject disc, space, pmat;
260: PetscCall(DMGetField(*subdm, field, NULL, &disc));
261: PetscCall(PetscObjectQuery(disc, "nullspace", &space));
262: if (space) PetscCall(PetscObjectCompose((PetscObject)*is, "nullspace", space));
263: PetscCall(PetscObjectQuery(disc, "nearnullspace", &space));
264: if (space) PetscCall(PetscObjectCompose((PetscObject)*is, "nearnullspace", space));
265: PetscCall(PetscObjectQuery(disc, "pmat", &pmat));
266: if (pmat) PetscCall(PetscObjectCompose((PetscObject)*is, "pmat", pmat));
267: }
268: PetscCall(PetscDSCopyConstants(dm->probs[field].ds, (*subdm)->probs[0].ds));
269: PetscCall(PetscDSCopyBoundary(dm->probs[field].ds, 1, fnum, (*subdm)->probs[0].ds));
270: PetscCall(PetscDSSelectEquations(dm->probs[field].ds, 1, fnum, (*subdm)->probs[0].ds));
271: }
272: if ((*subdm)->nullspaceConstructors[0] && is) {
273: MatNullSpace nullSpace;
275: PetscCall((*(*subdm)->nullspaceConstructors[0])(*subdm, 0, 0, &nullSpace));
276: PetscCall(PetscObjectCompose((PetscObject)*is, "nullspace", (PetscObject)nullSpace));
277: PetscCall(MatNullSpaceDestroy(&nullSpace));
278: }
279: if (dm->coarseMesh) PetscCall(DMCreateSubDM(dm->coarseMesh, numFields, fields, NULL, &(*subdm)->coarseMesh));
280: PetscFunctionReturn(PETSC_SUCCESS);
281: }
282: PetscCall(PetscSectionCreateSubsection(section, numFields, fields, &subsection));
283: PetscCall(DMSetLocalSection(*subdm, subsection));
284: PetscCall(PetscSectionDestroy(&subsection));
285: for (PetscInt f = 0; f < numFields; ++f) {
286: (*subdm)->nullspaceConstructors[f] = dm->nullspaceConstructors[fields[f]];
287: if ((*subdm)->nullspaceConstructors[f]) {
288: haveNull = PETSC_TRUE;
289: nf = f;
290: of = fields[f];
291: }
292: }
293: if (dm->probs) {
294: PetscCall(DMSetNumFields(*subdm, numFields));
295: for (PetscInt f = 0; f < numFields; ++f) {
296: PetscObject disc;
298: PetscCall(DMGetField(dm, fields[f], NULL, &disc));
299: PetscCall(DMSetField(*subdm, f, NULL, disc));
300: }
301: // TODO: if only FV, then cut down the components
302: PetscCall(DMCreateDS(*subdm));
303: if (numFields == 1 && is) {
304: PetscObject disc, space, pmat;
306: PetscCall(DMGetField(*subdm, 0, NULL, &disc));
307: PetscCall(PetscObjectQuery(disc, "nullspace", &space));
308: if (space) PetscCall(PetscObjectCompose((PetscObject)*is, "nullspace", space));
309: PetscCall(PetscObjectQuery(disc, "nearnullspace", &space));
310: if (space) PetscCall(PetscObjectCompose((PetscObject)*is, "nearnullspace", space));
311: PetscCall(PetscObjectQuery(disc, "pmat", &pmat));
312: if (pmat) PetscCall(PetscObjectCompose((PetscObject)*is, "pmat", pmat));
313: }
314: // Check if DSes record their DM fields
315: if (dm->probs[0].fields) {
316: PetscInt d, e;
318: for (d = 0, e = 0; d < dm->Nds && e < (*subdm)->Nds; ++d) {
319: const PetscInt Nf = dm->probs[d].ds->Nf;
320: const PetscInt *fld;
321: PetscInt f, g;
323: PetscCall(ISGetIndices(dm->probs[d].fields, &fld));
324: for (f = 0; f < Nf; ++f) {
325: for (g = 0; g < numFields; ++g)
326: if (fld[f] == fields[g]) break;
327: if (g < numFields) break;
328: }
329: PetscCall(ISRestoreIndices(dm->probs[d].fields, &fld));
330: if (f == Nf) continue;
331: PetscCall(PetscDSCopyConstants(dm->probs[d].ds, (*subdm)->probs[e].ds));
332: PetscCall(PetscDSCopyBoundary(dm->probs[d].ds, numFields, fields, (*subdm)->probs[e].ds));
333: // Translate DM fields to DS fields
334: {
335: IS infields, dsfields;
336: const PetscInt *fld, *ofld;
337: PetscInt *fidx;
338: PetscInt onf, nf;
340: PetscCall(ISCreateGeneral(PETSC_COMM_SELF, numFields, fields, PETSC_USE_POINTER, &infields));
341: PetscCall(ISIntersect(infields, dm->probs[d].fields, &dsfields));
342: PetscCall(ISDestroy(&infields));
343: PetscCall(ISGetLocalSize(dsfields, &nf));
344: PetscCheck(nf, PETSC_COMM_SELF, PETSC_ERR_PLIB, "DS cannot be supported on 0 fields");
345: PetscCall(ISGetIndices(dsfields, &fld));
346: PetscCall(ISGetLocalSize(dm->probs[d].fields, &onf));
347: PetscCall(ISGetIndices(dm->probs[d].fields, &ofld));
348: PetscCall(PetscMalloc1(nf, &fidx));
349: for (PetscInt f = 0, g = 0; f < onf && g < nf; ++f) {
350: if (ofld[f] == fld[g]) fidx[g++] = f;
351: }
352: PetscCall(ISRestoreIndices(dm->probs[d].fields, &ofld));
353: PetscCall(ISRestoreIndices(dsfields, &fld));
354: PetscCall(ISDestroy(&dsfields));
355: PetscCall(PetscDSSelectDiscretizations(dm->probs[0].ds, nf, fidx, (*subdm)->probs[0].ds));
356: PetscCall(PetscDSSelectEquations(dm->probs[0].ds, nf, fidx, (*subdm)->probs[0].ds));
357: PetscCall(PetscFree(fidx));
358: }
359: ++e;
360: }
361: } else {
362: PetscCall(PetscDSCopyConstants(dm->probs[0].ds, (*subdm)->probs[0].ds));
363: PetscCall(PetscDSCopyBoundary(dm->probs[0].ds, PETSC_DETERMINE, NULL, (*subdm)->probs[0].ds));
364: PetscCall(PetscDSSelectDiscretizations(dm->probs[0].ds, numFields, fields, (*subdm)->probs[0].ds));
365: PetscCall(PetscDSSelectEquations(dm->probs[0].ds, numFields, fields, (*subdm)->probs[0].ds));
366: }
367: }
368: if (haveNull && is) {
369: MatNullSpace nullSpace;
371: PetscCall((*(*subdm)->nullspaceConstructors[nf])(*subdm, of, nf, &nullSpace));
372: PetscCall(PetscObjectCompose((PetscObject)*is, "nullspace", (PetscObject)nullSpace));
373: PetscCall(MatNullSpaceDestroy(&nullSpace));
374: }
375: if (dm->coarseMesh) PetscCall(DMCreateSubDM(dm->coarseMesh, numFields, fields, NULL, &(*subdm)->coarseMesh));
376: PetscFunctionReturn(PETSC_SUCCESS);
377: }
379: /*@C
380: DMCreateSectionSubDM - Returns an `IS` and `subDM` containing a `PetscSection` that encapsulates a subproblem defined by a subset of the fields in a `PetscSection` in the `DM`.
382: Not Collective
384: Input Parameters:
385: + dm - The `DM` object
386: . numFields - The number of fields to incorporate into `subdm`
387: . fields - The field numbers of the selected fields
388: . numComps - The number of components from each field to incorporate into `subdm`, or PETSC_DECIDE for all components
389: - comps - The component numbers of the selected fields (omitted for PTESC_DECIDE fields)
391: Output Parameters:
392: + is - The global indices for the subproblem or `NULL`
393: - subdm - The `DM` for the subproblem, which must already have be cloned from `dm` or `NULL`
395: Level: intermediate
397: Notes:
398: If `is` and `subdm` are both `NULL` this does nothing
400: .seealso: `DMCreateSubDM()`, `DMGetLocalSection()`, `DMPlexSetMigrationSF()`, `DMView()`
401: @*/
402: PetscErrorCode DMCreateSectionSubDM(DM dm, PetscInt numFields, const PetscInt fields[], const PetscInt numComps[], const PetscInt comps[], IS *is, DM *subdm)
403: {
404: PetscSection section, sectionGlobal;
405: PetscInt Nf;
407: PetscFunctionBegin;
408: if (!numFields) PetscFunctionReturn(PETSC_SUCCESS);
409: PetscCall(DMGetLocalSection(dm, §ion));
410: PetscCall(DMGetGlobalSection(dm, §ionGlobal));
411: PetscCheck(section, PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_WRONG, "Must set default section for DM before splitting fields");
412: PetscCheck(sectionGlobal, PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_WRONG, "Must set default global section for DM before splitting fields");
413: PetscCall(PetscSectionGetNumFields(section, &Nf));
414: PetscCheck(numFields <= Nf, PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_WRONG, "Number of requested fields %" PetscInt_FMT " greater than number of DM fields %" PetscInt_FMT, numFields, Nf);
416: if (is) PetscCall(PetscSectionSelectFields_Private(section, sectionGlobal, numFields, fields, numComps, comps, is));
417: if (subdm) PetscCall(DMSelectFields_Private(dm, section, numFields, fields, numComps, comps, is, subdm));
418: PetscFunctionReturn(PETSC_SUCCESS);
419: }
421: /*@C
422: DMCreateSectionSuperDM - Returns an arrays of `IS` and a `DM` containing a `PetscSection` that encapsulates a superproblem defined by the array of `DM` and their `PetscSection`
424: Not Collective
426: Input Parameters:
427: + dms - The `DM` objects, the must all have the same topology; for example obtained with `DMClone()`
428: - len - The number of `DM` in `dms`
430: Output Parameters:
431: + is - The global indices for the subproblem, or `NULL`
432: - superdm - The `DM` for the superproblem, which must already have be cloned and contain the same topology as the `dms`
434: Level: intermediate
436: .seealso: `DMCreateSuperDM()`, `DMGetLocalSection()`, `DMPlexSetMigrationSF()`, `DMView()`
437: @*/
438: PetscErrorCode DMCreateSectionSuperDM(DM dms[], PetscInt len, IS **is, DM *superdm)
439: {
440: MPI_Comm comm;
441: PetscSection supersection, *sections, *sectionGlobals;
442: PetscInt *Nfs, Nf = 0, f, supf, oldf = -1, nullf = -1, i;
443: PetscBool haveNull = PETSC_FALSE;
445: PetscFunctionBegin;
446: PetscCall(PetscObjectGetComm((PetscObject)dms[0], &comm));
447: /* Pull out local and global sections */
448: PetscCall(PetscMalloc3(len, &Nfs, len, §ions, len, §ionGlobals));
449: for (i = 0; i < len; ++i) {
450: PetscCall(DMGetLocalSection(dms[i], §ions[i]));
451: PetscCall(DMGetGlobalSection(dms[i], §ionGlobals[i]));
452: PetscCheck(sections[i], comm, PETSC_ERR_ARG_WRONG, "Must set default section for DM before splitting fields");
453: PetscCheck(sectionGlobals[i], comm, PETSC_ERR_ARG_WRONG, "Must set default global section for DM before splitting fields");
454: PetscCall(PetscSectionGetNumFields(sections[i], &Nfs[i]));
455: Nf += Nfs[i];
456: }
457: /* Create the supersection */
458: PetscCall(PetscSectionCreateSupersection(sections, len, &supersection));
459: PetscCall(DMSetLocalSection(*superdm, supersection));
460: /* Create ISes */
461: if (is) {
462: PetscSection supersectionGlobal;
463: PetscInt bs = -1, startf = 0;
465: PetscCall(PetscMalloc1(len, is));
466: PetscCall(DMGetGlobalSection(*superdm, &supersectionGlobal));
467: for (i = 0; i < len; startf += Nfs[i], ++i) {
468: PetscInt *subIndices;
469: PetscInt subSize, subOff, pStart, pEnd, p, start, end, dummy;
471: PetscCall(PetscSectionGetChart(sectionGlobals[i], &pStart, &pEnd));
472: PetscCall(PetscSectionGetConstrainedStorageSize(sectionGlobals[i], &subSize));
473: PetscCall(PetscMalloc1(subSize, &subIndices));
474: for (p = pStart, subOff = 0; p < pEnd; ++p) {
475: PetscInt gdof, gcdof, gtdof, d;
477: PetscCall(PetscSectionGetDof(sectionGlobals[i], p, &gdof));
478: PetscCall(PetscSectionGetConstraintDof(sections[i], p, &gcdof));
479: gtdof = gdof - gcdof;
480: if (gdof > 0 && gtdof) {
481: if (bs < 0) {
482: bs = gtdof;
483: } else if (bs != gtdof) {
484: bs = 1;
485: }
486: PetscCall(DMGetGlobalFieldOffset_Private(*superdm, p, startf, &start, &dummy));
487: PetscCall(DMGetGlobalFieldOffset_Private(*superdm, p, startf + Nfs[i] - 1, &dummy, &end));
488: PetscCheck(end - start == gtdof, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Invalid number of global dofs %" PetscInt_FMT " != %" PetscInt_FMT " for dm %" PetscInt_FMT " on point %" PetscInt_FMT, end - start, gtdof, i, p);
489: for (d = start; d < end; ++d, ++subOff) subIndices[subOff] = d;
490: }
491: }
492: PetscCall(ISCreateGeneral(comm, subSize, subIndices, PETSC_OWN_POINTER, &(*is)[i]));
493: /* Must have same blocksize on all procs (some might have no points) */
494: {
495: PetscInt bs = -1, bsLocal[2], bsMinMax[2];
497: bsLocal[0] = bs < 0 ? PETSC_MAX_INT : bs;
498: bsLocal[1] = bs;
499: PetscCall(PetscGlobalMinMaxInt(comm, bsLocal, bsMinMax));
500: if (bsMinMax[0] != bsMinMax[1]) {
501: bs = 1;
502: } else {
503: bs = bsMinMax[0];
504: }
505: PetscCall(ISSetBlockSize((*is)[i], bs));
506: }
507: }
508: }
509: /* Preserve discretizations */
510: if (len && dms[0]->probs) {
511: PetscCall(DMSetNumFields(*superdm, Nf));
512: for (i = 0, supf = 0; i < len; ++i) {
513: for (f = 0; f < Nfs[i]; ++f, ++supf) {
514: PetscObject disc;
516: PetscCall(DMGetField(dms[i], f, NULL, &disc));
517: PetscCall(DMSetField(*superdm, supf, NULL, disc));
518: }
519: }
520: PetscCall(DMCreateDS(*superdm));
521: }
522: /* Preserve nullspaces */
523: for (i = 0, supf = 0; i < len; ++i) {
524: for (f = 0; f < Nfs[i]; ++f, ++supf) {
525: (*superdm)->nullspaceConstructors[supf] = dms[i]->nullspaceConstructors[f];
526: if ((*superdm)->nullspaceConstructors[supf]) {
527: haveNull = PETSC_TRUE;
528: nullf = supf;
529: oldf = f;
530: }
531: }
532: }
533: /* Attach nullspace to IS */
534: if (haveNull && is) {
535: MatNullSpace nullSpace;
537: PetscCall((*(*superdm)->nullspaceConstructors[nullf])(*superdm, oldf, nullf, &nullSpace));
538: PetscCall(PetscObjectCompose((PetscObject)(*is)[nullf], "nullspace", (PetscObject)nullSpace));
539: PetscCall(MatNullSpaceDestroy(&nullSpace));
540: }
541: PetscCall(PetscSectionDestroy(&supersection));
542: PetscCall(PetscFree3(Nfs, sections, sectionGlobals));
543: PetscFunctionReturn(PETSC_SUCCESS);
544: }