Actual source code: dmi.c

petsc-3.12.2 2019-11-22
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  1:  #include <petsc/private/dmimpl.h>
  2:  #include <petscds.h>

  4: PetscErrorCode DMCreateGlobalVector_Section_Private(DM dm,Vec *vec)
  5: {
  6:   PetscSection   gSection;
  7:   PetscInt       localSize, bs, blockSize = -1, pStart, pEnd, p;
  9:   PetscInt       in[2],out[2];

 12:   DMGetGlobalSection(dm, &gSection);
 13:   PetscSectionGetChart(gSection, &pStart, &pEnd);
 14:   for (p = pStart; p < pEnd; ++p) {
 15:     PetscInt dof, cdof;

 17:     PetscSectionGetDof(gSection, p, &dof);
 18:     PetscSectionGetConstraintDof(gSection, p, &cdof);

 20:     if (dof > 0) {
 21:       if (blockSize < 0 && dof-cdof > 0) {
 22:         /* set blockSize */
 23:         blockSize = dof-cdof;
 24:       } else if (dof-cdof != blockSize) {
 25:         /* non-identical blockSize, set it as 1 */
 26:         blockSize = 1;
 27:         break;
 28:       }
 29:     }
 30:   }

 32:   in[0] = blockSize < 0 ? PETSC_MIN_INT : -blockSize;
 33:   in[1] = blockSize;
 34:   MPIU_Allreduce(in,out,2,MPIU_INT,MPI_MAX,PetscObjectComm((PetscObject)dm));
 35:   /* -out[0] = min(blockSize), out[1] = max(blockSize) */
 36:   if (-out[0] == out[1]) {
 37:     bs = out[1];
 38:   } else bs = 1;

 40:   if (bs < 0) { /* Everyone was empty */
 41:     blockSize = 1;
 42:     bs        = 1;
 43:   }

 45:   PetscSectionGetConstrainedStorageSize(gSection, &localSize);
 46:   if (localSize%blockSize) SETERRQ2(PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_WRONG, "Mismatch between blocksize %d and local storage size %d", blockSize, localSize);
 47:   VecCreate(PetscObjectComm((PetscObject)dm), vec);
 48:   VecSetSizes(*vec, localSize, PETSC_DETERMINE);
 49:   VecSetBlockSize(*vec, bs);
 50:   VecSetType(*vec,dm->vectype);
 51:   VecSetDM(*vec, dm);
 52:   /* VecSetLocalToGlobalMapping(*vec, dm->ltogmap); */
 53:   return(0);
 54: }

 56: PetscErrorCode DMCreateLocalVector_Section_Private(DM dm,Vec *vec)
 57: {
 58:   PetscSection   section;
 59:   PetscInt       localSize, blockSize = -1, pStart, pEnd, p;

 63:   DMGetLocalSection(dm, &section);
 64:   PetscSectionGetChart(section, &pStart, &pEnd);
 65:   for (p = pStart; p < pEnd; ++p) {
 66:     PetscInt dof;

 68:     PetscSectionGetDof(section, p, &dof);
 69:     if ((blockSize < 0) && (dof > 0)) blockSize = dof;
 70:     if ((dof > 0) && (dof != blockSize)) {
 71:       blockSize = 1;
 72:       break;
 73:     }
 74:   }
 75:   PetscSectionGetStorageSize(section, &localSize);
 76:   VecCreate(PETSC_COMM_SELF, vec);
 77:   VecSetSizes(*vec, localSize, localSize);
 78:   VecSetBlockSize(*vec, blockSize);
 79:   VecSetType(*vec,dm->vectype);
 80:   VecSetDM(*vec, dm);
 81:   return(0);
 82: }

 84: /*@C
 85:   DMCreateSectionSubDM - Returns an IS and subDM+subSection encapsulating a subproblem defined by the fields in a PetscSection in the DM.

 87:   Not collective

 89:   Input Parameters:
 90: + dm        - The DM object
 91: . numFields - The number of fields in this subproblem
 92: - fields    - The field numbers of the selected fields

 94:   Output Parameters:
 95: + is - The global indices for the subproblem
 96: - subdm - The DM for the subproblem, which must already have be cloned from dm

 98:   Note: This handles all information in the DM class and the PetscSection. This is used as the basis for creating subDMs in specialized classes,
 99:   such as Plex and Forest.

101:   Level: intermediate

103: .seealso DMCreateSubDM(), DMGetLocalSection(), DMPlexSetMigrationSF(), DMView()
104: @*/
105: PetscErrorCode DMCreateSectionSubDM(DM dm, PetscInt numFields, const PetscInt fields[], IS *is, DM *subdm)
106: {
107:   PetscSection   section, sectionGlobal;
108:   PetscInt      *subIndices;
109:   PetscInt       subSize = 0, subOff = 0, Nf, f, pStart, pEnd, p;

113:   if (!numFields) return(0);
114:   DMGetLocalSection(dm, &section);
115:   DMGetGlobalSection(dm, &sectionGlobal);
116:   if (!section) SETERRQ(PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_WRONG, "Must set default section for DM before splitting fields");
117:   if (!sectionGlobal) SETERRQ(PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_WRONG, "Must set default global section for DM before splitting fields");
118:   PetscSectionGetNumFields(section, &Nf);
119:   if (numFields > Nf) SETERRQ2(PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_WRONG, "Number of requested fields %d greater than number of DM fields %d", numFields, Nf);
120:   if (is) {
121:     PetscInt bs, bsLocal[2], bsMinMax[2];

123:     for (f = 0, bs = 0; f < numFields; ++f) {
124:       PetscInt Nc;

126:       PetscSectionGetFieldComponents(section, fields[f], &Nc);
127:       bs  += Nc;
128:     }
129:     PetscSectionGetChart(sectionGlobal, &pStart, &pEnd);
130:     for (p = pStart; p < pEnd; ++p) {
131:       PetscInt gdof, pSubSize  = 0;

133:       PetscSectionGetDof(sectionGlobal, p, &gdof);
134:       if (gdof > 0) {
135:         for (f = 0; f < numFields; ++f) {
136:           PetscInt fdof, fcdof;

138:           PetscSectionGetFieldDof(section, p, fields[f], &fdof);
139:           PetscSectionGetFieldConstraintDof(section, p, fields[f], &fcdof);
140:           pSubSize += fdof-fcdof;
141:         }
142:         subSize += pSubSize;
143:         if (pSubSize && bs != pSubSize) {
144:           /* Layout does not admit a pointwise block size */
145:           bs = 1;
146:         }
147:       }
148:     }
149:     /* Must have same blocksize on all procs (some might have no points) */
150:     bsLocal[0] = bs < 0 ? PETSC_MAX_INT : bs; bsLocal[1] = bs;
151:     PetscGlobalMinMaxInt(PetscObjectComm((PetscObject) dm), bsLocal, bsMinMax);
152:     if (bsMinMax[0] != bsMinMax[1]) {bs = 1;}
153:     else                            {bs = bsMinMax[0];}
154:     PetscMalloc1(subSize, &subIndices);
155:     for (p = pStart; p < pEnd; ++p) {
156:       PetscInt gdof, goff;

158:       PetscSectionGetDof(sectionGlobal, p, &gdof);
159:       if (gdof > 0) {
160:         PetscSectionGetOffset(sectionGlobal, p, &goff);
161:         for (f = 0; f < numFields; ++f) {
162:           PetscInt fdof, fcdof, fc, f2, poff = 0;

164:           /* Can get rid of this loop by storing field information in the global section */
165:           for (f2 = 0; f2 < fields[f]; ++f2) {
166:             PetscSectionGetFieldDof(section, p, f2, &fdof);
167:             PetscSectionGetFieldConstraintDof(section, p, f2, &fcdof);
168:             poff += fdof-fcdof;
169:           }
170:           PetscSectionGetFieldDof(section, p, fields[f], &fdof);
171:           PetscSectionGetFieldConstraintDof(section, p, fields[f], &fcdof);
172:           for (fc = 0; fc < fdof-fcdof; ++fc, ++subOff) {
173:             subIndices[subOff] = goff+poff+fc;
174:           }
175:         }
176:       }
177:     }
178:     ISCreateGeneral(PetscObjectComm((PetscObject)dm), subSize, subIndices, PETSC_OWN_POINTER, is);
179:     if (bs > 1) {
180:       /* We need to check that the block size does not come from non-contiguous fields */
181:       PetscInt i, j, set = 1;
182:       for (i = 0; i < subSize; i += bs) {
183:         for (j = 0; j < bs; ++j) {
184:           if (subIndices[i+j] != subIndices[i]+j) {set = 0; break;}
185:         }
186:       }
187:       if (set) {ISSetBlockSize(*is, bs);}
188:     }
189:   }
190:   if (subdm) {
191:     PetscSection subsection;
192:     PetscBool    haveNull = PETSC_FALSE;
193:     PetscInt     f, nf = 0;

195:     PetscSectionCreateSubsection(section, numFields, fields, &subsection);
196:     DMSetLocalSection(*subdm, subsection);
197:     PetscSectionDestroy(&subsection);
198:     for (f = 0; f < numFields; ++f) {
199:       (*subdm)->nullspaceConstructors[f] = dm->nullspaceConstructors[fields[f]];
200:       if ((*subdm)->nullspaceConstructors[f]) {
201:         haveNull = PETSC_TRUE;
202:         nf       = f;
203:       }
204:     }
205:     if (haveNull && is) {
206:       MatNullSpace nullSpace;

208:       (*(*subdm)->nullspaceConstructors[nf])(*subdm, nf, &nullSpace);
209:       PetscObjectCompose((PetscObject) *is, "nullspace", (PetscObject) nullSpace);
210:       MatNullSpaceDestroy(&nullSpace);
211:     }
212:     if (dm->probs) {
213:       DMSetNumFields(*subdm, numFields);
214:       for (f = 0; f < numFields; ++f) {
215:         PetscObject disc;

217:         DMGetField(dm, fields[f], NULL, &disc);
218:         DMSetField(*subdm, f, NULL, disc);
219:       }
220:       DMCreateDS(*subdm);
221:       if (numFields == 1 && is) {
222:         PetscObject disc, space, pmat;

224:         DMGetField(*subdm, 0, NULL, &disc);
225:         PetscObjectQuery(disc, "nullspace", &space);
226:         if (space) {PetscObjectCompose((PetscObject) *is, "nullspace", space);}
227:         PetscObjectQuery(disc, "nearnullspace", &space);
228:         if (space) {PetscObjectCompose((PetscObject) *is, "nearnullspace", space);}
229:         PetscObjectQuery(disc, "pmat", &pmat);
230:         if (pmat) {PetscObjectCompose((PetscObject) *is, "pmat", pmat);}
231:       }
232:       PetscDSCopyConstants(dm->probs[0].ds, (*subdm)->probs[0].ds);
233:       PetscDSCopyBoundary(dm->probs[0].ds, (*subdm)->probs[0].ds);
234:       /* Translate DM fields to DS fields */
235:       if (dm->probs[0].fields) {
236:         IS              infields, dsfields;
237:         const PetscInt *fld, *ofld;
238:         PetscInt       *fidx;
239:         PetscInt        onf, nf, f, g;

241:         ISCreateGeneral(PETSC_COMM_SELF, numFields, fields, PETSC_USE_POINTER, &infields);
242:         ISIntersect(infields, dm->probs[0].fields, &dsfields);
243:         ISDestroy(&infields);
244:         ISGetLocalSize(dsfields, &nf);
245:         if (!nf) SETERRQ(PETSC_COMM_SELF, PETSC_ERR_PLIB, "DS cannot be supported on 0 fields");
246:         ISGetIndices(dsfields, &fld);
247:         ISGetLocalSize(dm->probs[0].fields, &onf);
248:         ISGetIndices(dm->probs[0].fields, &ofld);
249:         PetscMalloc1(nf, &fidx);
250:         for (f = 0, g = 0; f < onf && g < nf; ++f) {
251:           if (ofld[f] == fld[g]) fidx[g++] = f;
252:         }
253:         ISRestoreIndices(dm->probs[0].fields, &ofld);
254:         ISRestoreIndices(dsfields, &fld);
255:         ISDestroy(&dsfields);
256:         PetscDSSelectEquations(dm->probs[0].ds, nf, fidx, (*subdm)->probs[0].ds);
257:         PetscFree(fidx);
258:       } else {
259:         PetscDSSelectEquations(dm->probs[0].ds, numFields, fields, (*subdm)->probs[0].ds);
260:       }
261:     }
262:     if (dm->coarseMesh) {
263:       DMCreateSubDM(dm->coarseMesh, numFields, fields, NULL, &(*subdm)->coarseMesh);
264:     }
265:   }
266:   return(0);
267: }

269: /*@C
270:   DMCreateSectionSuperDM - Returns an arrays of ISes and DM+Section encapsulating a superproblem defined by the DM+Sections passed in.

272:   Not collective

274:   Input Parameter:
275: + dms - The DM objects
276: - len - The number of DMs

278:   Output Parameters:
279: + is - The global indices for the subproblem, or NULL
280: - superdm - The DM for the superproblem, which must already have be cloned

282:   Note: This handles all information in the DM class and the PetscSection. This is used as the basis for creating subDMs in specialized classes,
283:   such as Plex and Forest.

285:   Level: intermediate

287: .seealso DMCreateSuperDM(), DMGetLocalSection(), DMPlexSetMigrationSF(), DMView()
288: @*/
289: PetscErrorCode DMCreateSectionSuperDM(DM dms[], PetscInt len, IS **is, DM *superdm)
290: {
291:   MPI_Comm       comm;
292:   PetscSection   supersection, *sections, *sectionGlobals;
293:   PetscInt      *Nfs, Nf = 0, f, supf, nullf = -1, i;
294:   PetscBool      haveNull = PETSC_FALSE;

298:   PetscObjectGetComm((PetscObject)dms[0], &comm);
299:   /* Pull out local and global sections */
300:   PetscMalloc3(len, &Nfs, len, &sections, len, &sectionGlobals);
301:   for (i = 0 ; i < len; ++i) {
302:     DMGetLocalSection(dms[i], &sections[i]);
303:     DMGetGlobalSection(dms[i], &sectionGlobals[i]);
304:     if (!sections[i]) SETERRQ(comm, PETSC_ERR_ARG_WRONG, "Must set default section for DM before splitting fields");
305:     if (!sectionGlobals[i]) SETERRQ(comm, PETSC_ERR_ARG_WRONG, "Must set default global section for DM before splitting fields");
306:     PetscSectionGetNumFields(sections[i], &Nfs[i]);
307:     Nf += Nfs[i];
308:   }
309:   /* Create the supersection */
310:   PetscSectionCreateSupersection(sections, len, &supersection);
311:   DMSetLocalSection(*superdm, supersection);
312:   /* Create ISes */
313:   if (is) {
314:     PetscSection supersectionGlobal;
315:     PetscInt     bs = -1, startf = 0;

317:     PetscMalloc1(len, is);
318:     DMGetGlobalSection(*superdm, &supersectionGlobal);
319:     for (i = 0 ; i < len; startf += Nfs[i], ++i) {
320:       PetscInt *subIndices;
321:       PetscInt  subSize, subOff, pStart, pEnd, p, start, end, dummy;

323:       PetscSectionGetChart(sectionGlobals[i], &pStart, &pEnd);
324:       PetscSectionGetConstrainedStorageSize(sectionGlobals[i], &subSize);
325:       PetscMalloc1(subSize, &subIndices);
326:       for (p = pStart, subOff = 0; p < pEnd; ++p) {
327:         PetscInt gdof, gcdof, gtdof, d;

329:         PetscSectionGetDof(sectionGlobals[i], p, &gdof);
330:         PetscSectionGetConstraintDof(sections[i], p, &gcdof);
331:         gtdof = gdof - gcdof;
332:         if (gdof > 0 && gtdof) {
333:           if (bs < 0)           {bs = gtdof;}
334:           else if (bs != gtdof) {bs = 1;}
335:           DMGetGlobalFieldOffset_Private(*superdm, p, startf, &start, &dummy);
336:           DMGetGlobalFieldOffset_Private(*superdm, p, startf+Nfs[i]-1, &dummy, &end);
337:           if (end-start != gtdof) SETERRQ4(PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Invalid number of global dofs %D != %D for dm %D on point %D", end-start, gtdof, i, p);
338:           for (d = start; d < end; ++d, ++subOff) subIndices[subOff] = d;
339:         }
340:       }
341:       ISCreateGeneral(comm, subSize, subIndices, PETSC_OWN_POINTER, &(*is)[i]);
342:       /* Must have same blocksize on all procs (some might have no points) */
343:       {
344:         PetscInt bs = -1, bsLocal[2], bsMinMax[2];

346:         bsLocal[0] = bs < 0 ? PETSC_MAX_INT : bs; bsLocal[1] = bs;
347:         PetscGlobalMinMaxInt(comm, bsLocal, bsMinMax);
348:         if (bsMinMax[0] != bsMinMax[1]) {bs = 1;}
349:         else                            {bs = bsMinMax[0];}
350:         ISSetBlockSize((*is)[i], bs);
351:       }
352:     }
353:   }
354:   /* Preserve discretizations */
355:   if (len && dms[0]->probs) {
356:     DMSetNumFields(*superdm, Nf);
357:     for (i = 0, supf = 0; i < len; ++i) {
358:       for (f = 0; f < Nfs[i]; ++f, ++supf) {
359:         PetscObject disc;

361:         DMGetField(dms[i], f, NULL, &disc);
362:         DMSetField(*superdm, supf, NULL, disc);
363:       }
364:     }
365:     DMCreateDS(*superdm);
366:   }
367:   /* Preserve nullspaces */
368:   for (i = 0, supf = 0; i < len; ++i) {
369:     for (f = 0; f < Nfs[i]; ++f, ++supf) {
370:       (*superdm)->nullspaceConstructors[supf] = dms[i]->nullspaceConstructors[f];
371:       if ((*superdm)->nullspaceConstructors[supf]) {
372:         haveNull = PETSC_TRUE;
373:         nullf    = supf;
374:       }
375:     }
376:   }
377:   /* Attach nullspace to IS */
378:   if (haveNull && is) {
379:     MatNullSpace nullSpace;

381:     (*(*superdm)->nullspaceConstructors[nullf])(*superdm, nullf, &nullSpace);
382:     PetscObjectCompose((PetscObject) (*is)[nullf], "nullspace", (PetscObject) nullSpace);
383:     MatNullSpaceDestroy(&nullSpace);
384:   }
385:   PetscSectionDestroy(&supersection);
386:   PetscFree3(Nfs, sections, sectionGlobals);
387:   return(0);
388: }