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: /*@C
89: 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`.
91: Not Collective
93: Input Parameters:
94: + dm - The `DM` object
95: . numFields - The number of fields to incorporate into `subdm`
96: - fields - The field numbers of the selected fields
98: Output Parameters:
99: + is - The global indices for the subproblem or `NULL`
100: - subdm - The `DM` for the subproblem, which must already have be cloned from `dm` or `NULL`
102: Level: intermediate
104: Note:
105: If `is` and `subdm` are both `NULL` this does nothing
107: .seealso: `DMCreateSubDM()`, `DMGetLocalSection()`, `DMPlexSetMigrationSF()`, `DMView()`
108: @*/
109: PetscErrorCode DMCreateSectionSubDM(DM dm, PetscInt numFields, const PetscInt fields[], IS *is, DM *subdm)
110: {
111: PetscSection section, sectionGlobal;
112: PetscInt *subIndices;
113: PetscInt subSize = 0, subOff = 0, Nf, f, pStart, pEnd, p;
115: PetscFunctionBegin;
116: if (!numFields) PetscFunctionReturn(PETSC_SUCCESS);
117: PetscCall(DMGetLocalSection(dm, §ion));
118: PetscCall(DMGetGlobalSection(dm, §ionGlobal));
119: PetscCheck(section, PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_WRONG, "Must set default section for DM before splitting fields");
120: PetscCheck(sectionGlobal, PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_WRONG, "Must set default global section for DM before splitting fields");
121: PetscCall(PetscSectionGetNumFields(section, &Nf));
122: 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);
123: if (is) {
124: PetscInt bs, bsLocal[2], bsMinMax[2];
126: for (f = 0, bs = 0; f < numFields; ++f) {
127: PetscInt Nc;
129: PetscCall(PetscSectionGetFieldComponents(section, fields[f], &Nc));
130: bs += Nc;
131: }
132: PetscCall(PetscSectionGetChart(sectionGlobal, &pStart, &pEnd));
133: for (p = pStart; p < pEnd; ++p) {
134: PetscInt gdof, pSubSize = 0;
136: PetscCall(PetscSectionGetDof(sectionGlobal, p, &gdof));
137: if (gdof > 0) {
138: for (f = 0; f < numFields; ++f) {
139: PetscInt fdof, fcdof;
141: PetscCall(PetscSectionGetFieldDof(section, p, fields[f], &fdof));
142: PetscCall(PetscSectionGetFieldConstraintDof(section, p, fields[f], &fcdof));
143: pSubSize += fdof - fcdof;
144: }
145: subSize += pSubSize;
146: if (pSubSize && bs != pSubSize) {
147: /* Layout does not admit a pointwise block size */
148: bs = 1;
149: }
150: }
151: }
152: /* Must have same blocksize on all procs (some might have no points) */
153: bsLocal[0] = bs < 0 ? PETSC_MAX_INT : bs;
154: bsLocal[1] = bs;
155: PetscCall(PetscGlobalMinMaxInt(PetscObjectComm((PetscObject)dm), bsLocal, bsMinMax));
156: if (bsMinMax[0] != bsMinMax[1]) {
157: bs = 1;
158: } else {
159: bs = bsMinMax[0];
160: }
161: PetscCall(PetscMalloc1(subSize, &subIndices));
162: for (p = pStart; p < pEnd; ++p) {
163: PetscInt gdof, goff;
165: PetscCall(PetscSectionGetDof(sectionGlobal, p, &gdof));
166: if (gdof > 0) {
167: PetscCall(PetscSectionGetOffset(sectionGlobal, p, &goff));
168: for (f = 0; f < numFields; ++f) {
169: PetscInt fdof, fcdof, fc, f2, poff = 0;
171: /* Can get rid of this loop by storing field information in the global section */
172: for (f2 = 0; f2 < fields[f]; ++f2) {
173: PetscCall(PetscSectionGetFieldDof(section, p, f2, &fdof));
174: PetscCall(PetscSectionGetFieldConstraintDof(section, p, f2, &fcdof));
175: poff += fdof - fcdof;
176: }
177: PetscCall(PetscSectionGetFieldDof(section, p, fields[f], &fdof));
178: PetscCall(PetscSectionGetFieldConstraintDof(section, p, fields[f], &fcdof));
179: for (fc = 0; fc < fdof - fcdof; ++fc, ++subOff) subIndices[subOff] = goff + poff + fc;
180: }
181: }
182: }
183: PetscCall(ISCreateGeneral(PetscObjectComm((PetscObject)dm), subSize, subIndices, PETSC_OWN_POINTER, is));
184: if (bs > 1) {
185: /* We need to check that the block size does not come from non-contiguous fields */
186: PetscInt i, j, set = 1, rset = 1;
187: for (i = 0; i < subSize; i += bs) {
188: for (j = 0; j < bs; ++j) {
189: if (subIndices[i + j] != subIndices[i] + j) {
190: set = 0;
191: break;
192: }
193: }
194: }
195: PetscCall(MPIU_Allreduce(&set, &rset, 1, MPIU_INT, MPI_PROD, PetscObjectComm((PetscObject)dm)));
196: if (rset) PetscCall(ISSetBlockSize(*is, bs));
197: }
198: }
199: if (subdm) {
200: PetscSection subsection;
201: PetscBool haveNull = PETSC_FALSE;
202: PetscInt f, nf = 0, of = 0;
204: PetscCall(PetscSectionCreateSubsection(section, numFields, fields, &subsection));
205: PetscCall(DMSetLocalSection(*subdm, subsection));
206: PetscCall(PetscSectionDestroy(&subsection));
207: for (f = 0; f < numFields; ++f) {
208: (*subdm)->nullspaceConstructors[f] = dm->nullspaceConstructors[fields[f]];
209: if ((*subdm)->nullspaceConstructors[f]) {
210: haveNull = PETSC_TRUE;
211: nf = f;
212: of = fields[f];
213: }
214: }
215: if (dm->probs) {
216: PetscCall(DMSetNumFields(*subdm, numFields));
217: for (f = 0; f < numFields; ++f) {
218: PetscObject disc;
220: PetscCall(DMGetField(dm, fields[f], NULL, &disc));
221: PetscCall(DMSetField(*subdm, f, NULL, disc));
222: }
223: PetscCall(DMCreateDS(*subdm));
224: if (numFields == 1 && is) {
225: PetscObject disc, space, pmat;
227: PetscCall(DMGetField(*subdm, 0, NULL, &disc));
228: PetscCall(PetscObjectQuery(disc, "nullspace", &space));
229: if (space) PetscCall(PetscObjectCompose((PetscObject)*is, "nullspace", space));
230: PetscCall(PetscObjectQuery(disc, "nearnullspace", &space));
231: if (space) PetscCall(PetscObjectCompose((PetscObject)*is, "nearnullspace", space));
232: PetscCall(PetscObjectQuery(disc, "pmat", &pmat));
233: if (pmat) PetscCall(PetscObjectCompose((PetscObject)*is, "pmat", pmat));
234: }
235: /* Check if DSes record their DM fields */
236: if (dm->probs[0].fields) {
237: PetscInt d, e;
239: for (d = 0, e = 0; d < dm->Nds && e < (*subdm)->Nds; ++d) {
240: const PetscInt Nf = dm->probs[d].ds->Nf;
241: const PetscInt *fld;
242: PetscInt f, g;
244: PetscCall(ISGetIndices(dm->probs[d].fields, &fld));
245: for (f = 0; f < Nf; ++f) {
246: for (g = 0; g < numFields; ++g)
247: if (fld[f] == fields[g]) break;
248: if (g < numFields) break;
249: }
250: PetscCall(ISRestoreIndices(dm->probs[d].fields, &fld));
251: if (f == Nf) continue;
252: PetscCall(PetscDSCopyConstants(dm->probs[d].ds, (*subdm)->probs[e].ds));
253: PetscCall(PetscDSCopyBoundary(dm->probs[d].ds, numFields, fields, (*subdm)->probs[e].ds));
254: /* Translate DM fields to DS fields */
255: {
256: IS infields, dsfields;
257: const PetscInt *fld, *ofld;
258: PetscInt *fidx;
259: PetscInt onf, nf, f, g;
261: PetscCall(ISCreateGeneral(PETSC_COMM_SELF, numFields, fields, PETSC_USE_POINTER, &infields));
262: PetscCall(ISIntersect(infields, dm->probs[d].fields, &dsfields));
263: PetscCall(ISDestroy(&infields));
264: PetscCall(ISGetLocalSize(dsfields, &nf));
265: PetscCheck(nf, PETSC_COMM_SELF, PETSC_ERR_PLIB, "DS cannot be supported on 0 fields");
266: PetscCall(ISGetIndices(dsfields, &fld));
267: PetscCall(ISGetLocalSize(dm->probs[d].fields, &onf));
268: PetscCall(ISGetIndices(dm->probs[d].fields, &ofld));
269: PetscCall(PetscMalloc1(nf, &fidx));
270: for (f = 0, g = 0; f < onf && g < nf; ++f) {
271: if (ofld[f] == fld[g]) fidx[g++] = f;
272: }
273: PetscCall(ISRestoreIndices(dm->probs[d].fields, &ofld));
274: PetscCall(ISRestoreIndices(dsfields, &fld));
275: PetscCall(ISDestroy(&dsfields));
276: PetscCall(PetscDSSelectDiscretizations(dm->probs[0].ds, nf, fidx, (*subdm)->probs[0].ds));
277: PetscCall(PetscDSSelectEquations(dm->probs[0].ds, nf, fidx, (*subdm)->probs[0].ds));
278: PetscCall(PetscFree(fidx));
279: }
280: ++e;
281: }
282: } else {
283: PetscCall(PetscDSCopyConstants(dm->probs[0].ds, (*subdm)->probs[0].ds));
284: PetscCall(PetscDSCopyBoundary(dm->probs[0].ds, PETSC_DETERMINE, NULL, (*subdm)->probs[0].ds));
285: PetscCall(PetscDSSelectDiscretizations(dm->probs[0].ds, numFields, fields, (*subdm)->probs[0].ds));
286: PetscCall(PetscDSSelectEquations(dm->probs[0].ds, numFields, fields, (*subdm)->probs[0].ds));
287: }
288: }
289: if (haveNull && is) {
290: MatNullSpace nullSpace;
292: PetscCall((*(*subdm)->nullspaceConstructors[nf])(*subdm, of, nf, &nullSpace));
293: PetscCall(PetscObjectCompose((PetscObject)*is, "nullspace", (PetscObject)nullSpace));
294: PetscCall(MatNullSpaceDestroy(&nullSpace));
295: }
296: if (dm->coarseMesh) PetscCall(DMCreateSubDM(dm->coarseMesh, numFields, fields, NULL, &(*subdm)->coarseMesh));
297: }
298: PetscFunctionReturn(PETSC_SUCCESS);
299: }
301: /*@C
302: 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`
304: Not Collective
306: Input Parameters:
307: + dms - The `DM` objects, the must all have the same topology; for example obtained with `DMClone()`
308: - len - The number of `DM` in `dms`
310: Output Parameters:
311: + is - The global indices for the subproblem, or `NULL`
312: - superdm - The `DM` for the superproblem, which must already have be cloned and contain the same topology as the `dms`
314: Level: intermediate
316: .seealso: `DMCreateSuperDM()`, `DMGetLocalSection()`, `DMPlexSetMigrationSF()`, `DMView()`
317: @*/
318: PetscErrorCode DMCreateSectionSuperDM(DM dms[], PetscInt len, IS **is, DM *superdm)
319: {
320: MPI_Comm comm;
321: PetscSection supersection, *sections, *sectionGlobals;
322: PetscInt *Nfs, Nf = 0, f, supf, oldf = -1, nullf = -1, i;
323: PetscBool haveNull = PETSC_FALSE;
325: PetscFunctionBegin;
326: PetscCall(PetscObjectGetComm((PetscObject)dms[0], &comm));
327: /* Pull out local and global sections */
328: PetscCall(PetscMalloc3(len, &Nfs, len, §ions, len, §ionGlobals));
329: for (i = 0; i < len; ++i) {
330: PetscCall(DMGetLocalSection(dms[i], §ions[i]));
331: PetscCall(DMGetGlobalSection(dms[i], §ionGlobals[i]));
332: PetscCheck(sections[i], comm, PETSC_ERR_ARG_WRONG, "Must set default section for DM before splitting fields");
333: PetscCheck(sectionGlobals[i], comm, PETSC_ERR_ARG_WRONG, "Must set default global section for DM before splitting fields");
334: PetscCall(PetscSectionGetNumFields(sections[i], &Nfs[i]));
335: Nf += Nfs[i];
336: }
337: /* Create the supersection */
338: PetscCall(PetscSectionCreateSupersection(sections, len, &supersection));
339: PetscCall(DMSetLocalSection(*superdm, supersection));
340: /* Create ISes */
341: if (is) {
342: PetscSection supersectionGlobal;
343: PetscInt bs = -1, startf = 0;
345: PetscCall(PetscMalloc1(len, is));
346: PetscCall(DMGetGlobalSection(*superdm, &supersectionGlobal));
347: for (i = 0; i < len; startf += Nfs[i], ++i) {
348: PetscInt *subIndices;
349: PetscInt subSize, subOff, pStart, pEnd, p, start, end, dummy;
351: PetscCall(PetscSectionGetChart(sectionGlobals[i], &pStart, &pEnd));
352: PetscCall(PetscSectionGetConstrainedStorageSize(sectionGlobals[i], &subSize));
353: PetscCall(PetscMalloc1(subSize, &subIndices));
354: for (p = pStart, subOff = 0; p < pEnd; ++p) {
355: PetscInt gdof, gcdof, gtdof, d;
357: PetscCall(PetscSectionGetDof(sectionGlobals[i], p, &gdof));
358: PetscCall(PetscSectionGetConstraintDof(sections[i], p, &gcdof));
359: gtdof = gdof - gcdof;
360: if (gdof > 0 && gtdof) {
361: if (bs < 0) {
362: bs = gtdof;
363: } else if (bs != gtdof) {
364: bs = 1;
365: }
366: PetscCall(DMGetGlobalFieldOffset_Private(*superdm, p, startf, &start, &dummy));
367: PetscCall(DMGetGlobalFieldOffset_Private(*superdm, p, startf + Nfs[i] - 1, &dummy, &end));
368: 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);
369: for (d = start; d < end; ++d, ++subOff) subIndices[subOff] = d;
370: }
371: }
372: PetscCall(ISCreateGeneral(comm, subSize, subIndices, PETSC_OWN_POINTER, &(*is)[i]));
373: /* Must have same blocksize on all procs (some might have no points) */
374: {
375: PetscInt bs = -1, bsLocal[2], bsMinMax[2];
377: bsLocal[0] = bs < 0 ? PETSC_MAX_INT : bs;
378: bsLocal[1] = bs;
379: PetscCall(PetscGlobalMinMaxInt(comm, bsLocal, bsMinMax));
380: if (bsMinMax[0] != bsMinMax[1]) {
381: bs = 1;
382: } else {
383: bs = bsMinMax[0];
384: }
385: PetscCall(ISSetBlockSize((*is)[i], bs));
386: }
387: }
388: }
389: /* Preserve discretizations */
390: if (len && dms[0]->probs) {
391: PetscCall(DMSetNumFields(*superdm, Nf));
392: for (i = 0, supf = 0; i < len; ++i) {
393: for (f = 0; f < Nfs[i]; ++f, ++supf) {
394: PetscObject disc;
396: PetscCall(DMGetField(dms[i], f, NULL, &disc));
397: PetscCall(DMSetField(*superdm, supf, NULL, disc));
398: }
399: }
400: PetscCall(DMCreateDS(*superdm));
401: }
402: /* Preserve nullspaces */
403: for (i = 0, supf = 0; i < len; ++i) {
404: for (f = 0; f < Nfs[i]; ++f, ++supf) {
405: (*superdm)->nullspaceConstructors[supf] = dms[i]->nullspaceConstructors[f];
406: if ((*superdm)->nullspaceConstructors[supf]) {
407: haveNull = PETSC_TRUE;
408: nullf = supf;
409: oldf = f;
410: }
411: }
412: }
413: /* Attach nullspace to IS */
414: if (haveNull && is) {
415: MatNullSpace nullSpace;
417: PetscCall((*(*superdm)->nullspaceConstructors[nullf])(*superdm, oldf, nullf, &nullSpace));
418: PetscCall(PetscObjectCompose((PetscObject)(*is)[nullf], "nullspace", (PetscObject)nullSpace));
419: PetscCall(MatNullSpaceDestroy(&nullSpace));
420: }
421: PetscCall(PetscSectionDestroy(&supersection));
422: PetscCall(PetscFree3(Nfs, sections, sectionGlobals));
423: PetscFunctionReturn(PETSC_SUCCESS);
424: }