xref: /petsc/src/dm/interface/dmi.c (revision 55e7fe800d976e85ed2b5cd8bfdef564daa37bd9)
1 #include <petsc/private/dmimpl.h>     /*I      "petscdm.h"     I*/
2 #include <petscds.h>
3 
4 PetscErrorCode DMCreateGlobalVector_Section_Private(DM dm,Vec *vec)
5 {
6   PetscSection   gSection;
7   PetscInt       localSize, bs, blockSize = -1, pStart, pEnd, p;
8   PetscErrorCode ierr;
9   PetscInt       in[2],out[2];
10 
11   PetscFunctionBegin;
12   ierr = DMGetGlobalSection(dm, &gSection);CHKERRQ(ierr);
13   ierr = PetscSectionGetChart(gSection, &pStart, &pEnd);CHKERRQ(ierr);
14   for (p = pStart; p < pEnd; ++p) {
15     PetscInt dof, cdof;
16 
17     ierr = PetscSectionGetDof(gSection, p, &dof);CHKERRQ(ierr);
18     ierr = PetscSectionGetConstraintDof(gSection, p, &cdof);CHKERRQ(ierr);
19 
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   }
31 
32   in[0] = blockSize < 0 ? PETSC_MIN_INT : -blockSize;
33   in[1] = blockSize;
34   ierr = MPIU_Allreduce(in,out,2,MPIU_INT,MPI_MAX,PetscObjectComm((PetscObject)dm));CHKERRQ(ierr);
35   /* -out[0] = min(blockSize), out[1] = max(blockSize) */
36   if (-out[0] == out[1]) {
37     bs = out[1];
38   } else bs = 1;
39 
40   if (bs < 0) { /* Everyone was empty */
41     blockSize = 1;
42     bs        = 1;
43   }
44 
45   ierr = PetscSectionGetConstrainedStorageSize(gSection, &localSize);CHKERRQ(ierr);
46   if (localSize%blockSize) SETERRQ2(PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_WRONG, "Mismatch between blocksize %d and local storage size %d", blockSize, localSize);
47   ierr = VecCreate(PetscObjectComm((PetscObject)dm), vec);CHKERRQ(ierr);
48   ierr = VecSetSizes(*vec, localSize, PETSC_DETERMINE);CHKERRQ(ierr);
49   ierr = VecSetBlockSize(*vec, bs);CHKERRQ(ierr);
50   ierr = VecSetType(*vec,dm->vectype);CHKERRQ(ierr);
51   ierr = VecSetDM(*vec, dm);CHKERRQ(ierr);
52   /* ierr = VecSetLocalToGlobalMapping(*vec, dm->ltogmap);CHKERRQ(ierr); */
53   PetscFunctionReturn(0);
54 }
55 
56 PetscErrorCode DMCreateLocalVector_Section_Private(DM dm,Vec *vec)
57 {
58   PetscSection   section;
59   PetscInt       localSize, blockSize = -1, pStart, pEnd, p;
60   PetscErrorCode ierr;
61 
62   PetscFunctionBegin;
63   ierr = DMGetSection(dm, &section);CHKERRQ(ierr);
64   ierr = PetscSectionGetChart(section, &pStart, &pEnd);CHKERRQ(ierr);
65   for (p = pStart; p < pEnd; ++p) {
66     PetscInt dof;
67 
68     ierr = PetscSectionGetDof(section, p, &dof);CHKERRQ(ierr);
69     if ((blockSize < 0) && (dof > 0)) blockSize = dof;
70     if ((dof > 0) && (dof != blockSize)) {
71       blockSize = 1;
72       break;
73     }
74   }
75   ierr = PetscSectionGetStorageSize(section, &localSize);CHKERRQ(ierr);
76   ierr = VecCreate(PETSC_COMM_SELF, vec);CHKERRQ(ierr);
77   ierr = VecSetSizes(*vec, localSize, localSize);CHKERRQ(ierr);
78   ierr = VecSetBlockSize(*vec, blockSize);CHKERRQ(ierr);
79   ierr = VecSetType(*vec,dm->vectype);CHKERRQ(ierr);
80   ierr = VecSetDM(*vec, dm);CHKERRQ(ierr);
81   PetscFunctionReturn(0);
82 }
83 
84 /* This assumes that the DM has been cloned prior to the call */
85 PetscErrorCode DMCreateSubDM_Section_Private(DM dm, PetscInt numFields, const PetscInt fields[], IS *is, DM *subdm)
86 {
87   PetscSection   section, sectionGlobal;
88   PetscInt      *subIndices;
89   PetscInt       subSize = 0, subOff = 0, nF, f, pStart, pEnd, p;
90   PetscErrorCode ierr;
91 
92   PetscFunctionBegin;
93   if (!numFields) PetscFunctionReturn(0);
94   ierr = DMGetSection(dm, &section);CHKERRQ(ierr);
95   ierr = DMGetGlobalSection(dm, &sectionGlobal);CHKERRQ(ierr);
96   if (!section) SETERRQ(PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_WRONG, "Must set default section for DM before splitting fields");
97   if (!sectionGlobal) SETERRQ(PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_WRONG, "Must set default global section for DM before splitting fields");
98   ierr = PetscSectionGetNumFields(section, &nF);CHKERRQ(ierr);
99   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);
100   if (is) {
101     PetscInt bs, bsLocal[2], bsMinMax[2];
102 
103     for (f = 0, bs = 0; f < numFields; ++f) {
104       PetscInt Nc;
105 
106       ierr = PetscSectionGetFieldComponents(section, fields[f], &Nc);CHKERRQ(ierr);
107       bs  += Nc;
108     }
109     ierr = PetscSectionGetChart(sectionGlobal, &pStart, &pEnd);CHKERRQ(ierr);
110     for (p = pStart; p < pEnd; ++p) {
111       PetscInt gdof, pSubSize  = 0;
112 
113       ierr = PetscSectionGetDof(sectionGlobal, p, &gdof);CHKERRQ(ierr);
114       if (gdof > 0) {
115         for (f = 0; f < numFields; ++f) {
116           PetscInt fdof, fcdof;
117 
118           ierr     = PetscSectionGetFieldDof(section, p, fields[f], &fdof);CHKERRQ(ierr);
119           ierr     = PetscSectionGetFieldConstraintDof(section, p, fields[f], &fcdof);CHKERRQ(ierr);
120           pSubSize += fdof-fcdof;
121         }
122         subSize += pSubSize;
123         if (pSubSize && bs != pSubSize) {
124           /* Layout does not admit a pointwise block size */
125           bs = 1;
126         }
127       }
128     }
129     /* Must have same blocksize on all procs (some might have no points) */
130     bsLocal[0] = bs < 0 ? PETSC_MAX_INT : bs; bsLocal[1] = bs;
131     ierr = PetscGlobalMinMaxInt(PetscObjectComm((PetscObject) dm), bsLocal, bsMinMax);CHKERRQ(ierr);
132     if (bsMinMax[0] != bsMinMax[1]) {bs = 1;}
133     else                            {bs = bsMinMax[0];}
134     ierr = PetscMalloc1(subSize, &subIndices);CHKERRQ(ierr);
135     for (p = pStart; p < pEnd; ++p) {
136       PetscInt gdof, goff;
137 
138       ierr = PetscSectionGetDof(sectionGlobal, p, &gdof);CHKERRQ(ierr);
139       if (gdof > 0) {
140         ierr = PetscSectionGetOffset(sectionGlobal, p, &goff);CHKERRQ(ierr);
141         for (f = 0; f < numFields; ++f) {
142           PetscInt fdof, fcdof, fc, f2, poff = 0;
143 
144           /* Can get rid of this loop by storing field information in the global section */
145           for (f2 = 0; f2 < fields[f]; ++f2) {
146             ierr  = PetscSectionGetFieldDof(section, p, f2, &fdof);CHKERRQ(ierr);
147             ierr  = PetscSectionGetFieldConstraintDof(section, p, f2, &fcdof);CHKERRQ(ierr);
148             poff += fdof-fcdof;
149           }
150           ierr = PetscSectionGetFieldDof(section, p, fields[f], &fdof);CHKERRQ(ierr);
151           ierr = PetscSectionGetFieldConstraintDof(section, p, fields[f], &fcdof);CHKERRQ(ierr);
152           for (fc = 0; fc < fdof-fcdof; ++fc, ++subOff) {
153             subIndices[subOff] = goff+poff+fc;
154           }
155         }
156       }
157     }
158     ierr = ISCreateGeneral(PetscObjectComm((PetscObject)dm), subSize, subIndices, PETSC_OWN_POINTER, is);CHKERRQ(ierr);
159     if (bs > 1) {
160       /* We need to check that the block size does not come from non-contiguous fields */
161       PetscInt i, j, set = 1;
162       for (i = 0; i < subSize; i += bs) {
163         for (j = 0; j < bs; ++j) {
164           if (subIndices[i+j] != subIndices[i]+j) {set = 0; break;}
165         }
166       }
167       if (set) {ierr = ISSetBlockSize(*is, bs);CHKERRQ(ierr);}
168     }
169   }
170   if (subdm) {
171     PetscSection subsection;
172     PetscBool    haveNull = PETSC_FALSE;
173     PetscInt     f, nf = 0;
174 
175     ierr = PetscSectionCreateSubsection(section, numFields, fields, &subsection);CHKERRQ(ierr);
176     ierr = DMSetSection(*subdm, subsection);CHKERRQ(ierr);
177     ierr = PetscSectionDestroy(&subsection);CHKERRQ(ierr);
178     for (f = 0; f < numFields; ++f) {
179       (*subdm)->nullspaceConstructors[f] = dm->nullspaceConstructors[fields[f]];
180       if ((*subdm)->nullspaceConstructors[f]) {
181         haveNull = PETSC_TRUE;
182         nf       = f;
183       }
184     }
185     if (haveNull && is) {
186       MatNullSpace nullSpace;
187 
188       ierr = (*(*subdm)->nullspaceConstructors[nf])(*subdm, nf, &nullSpace);CHKERRQ(ierr);
189       ierr = PetscObjectCompose((PetscObject) *is, "nullspace", (PetscObject) nullSpace);CHKERRQ(ierr);
190       ierr = MatNullSpaceDestroy(&nullSpace);CHKERRQ(ierr);
191     }
192     if (dm->prob) {
193       PetscInt Nf;
194 
195       ierr = PetscDSGetNumFields(dm->prob, &Nf);CHKERRQ(ierr);
196       if (nF != Nf) SETERRQ2(PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_WRONG, "The number of DM fields %d does not match the number of Section fields %d", Nf, nF);
197       ierr = DMSetNumFields(*subdm, numFields);CHKERRQ(ierr);
198       for (f = 0; f < numFields; ++f) {
199         PetscObject disc;
200 
201         ierr = DMGetField(dm, fields[f], &disc);CHKERRQ(ierr);
202         ierr = DMSetField(*subdm, f, disc);CHKERRQ(ierr);
203       }
204       if (numFields == 1 && is) {
205         PetscObject disc, space, pmat;
206 
207         ierr = DMGetField(*subdm, 0, &disc);CHKERRQ(ierr);
208         ierr = PetscObjectQuery(disc, "nullspace", &space);CHKERRQ(ierr);
209         if (space) {ierr = PetscObjectCompose((PetscObject) *is, "nullspace", space);CHKERRQ(ierr);}
210         ierr = PetscObjectQuery(disc, "nearnullspace", &space);CHKERRQ(ierr);
211         if (space) {ierr = PetscObjectCompose((PetscObject) *is, "nearnullspace", space);CHKERRQ(ierr);}
212         ierr = PetscObjectQuery(disc, "pmat", &pmat);CHKERRQ(ierr);
213         if (pmat) {ierr = PetscObjectCompose((PetscObject) *is, "pmat", pmat);CHKERRQ(ierr);}
214       }
215       ierr = PetscDSCopyConstants(dm->prob, (*subdm)->prob);CHKERRQ(ierr);
216       ierr = PetscDSCopyBoundary(dm->prob, (*subdm)->prob);CHKERRQ(ierr);
217       ierr = PetscDSSelectEquations(dm->prob, numFields, fields, (*subdm)->prob);CHKERRQ(ierr);
218     }
219     if (dm->coarseMesh) {
220       ierr = DMCreateSubDM(dm->coarseMesh, numFields, fields, NULL, &(*subdm)->coarseMesh);CHKERRQ(ierr);
221     }
222   }
223   PetscFunctionReturn(0);
224 }
225 
226 /* This assumes that the DM has been cloned prior to the call */
227 PetscErrorCode DMCreateSuperDM_Section_Private(DM dms[], PetscInt len, IS **is, DM *superdm)
228 {
229   MPI_Comm       comm;
230   PetscSection   supersection, *sections, *sectionGlobals;
231   PetscInt      *Nfs, Nf = 0, f, supf, nullf = -1, i;
232   PetscBool      haveNull = PETSC_FALSE;
233   PetscErrorCode ierr;
234 
235   PetscFunctionBegin;
236   ierr = PetscObjectGetComm((PetscObject)dms[0], &comm);CHKERRQ(ierr);
237   /* Pull out local and global sections */
238   ierr = PetscMalloc3(len, &Nfs, len, &sections, len, &sectionGlobals);CHKERRQ(ierr);
239   for (i = 0 ; i < len; ++i) {
240     ierr = DMGetSection(dms[i], &sections[i]);CHKERRQ(ierr);
241     ierr = DMGetGlobalSection(dms[i], &sectionGlobals[i]);CHKERRQ(ierr);
242     if (!sections[i]) SETERRQ(comm, PETSC_ERR_ARG_WRONG, "Must set default section for DM before splitting fields");
243     if (!sectionGlobals[i]) SETERRQ(comm, PETSC_ERR_ARG_WRONG, "Must set default global section for DM before splitting fields");
244     ierr = PetscSectionGetNumFields(sections[i], &Nfs[i]);CHKERRQ(ierr);
245     Nf += Nfs[i];
246   }
247   /* Create the supersection */
248   ierr = PetscSectionCreateSupersection(sections, len, &supersection);CHKERRQ(ierr);
249   ierr = DMSetSection(*superdm, supersection);CHKERRQ(ierr);
250   /* Create ISes */
251   if (is) {
252     PetscSection supersectionGlobal;
253     PetscInt     bs = -1, startf = 0;
254 
255     ierr = PetscMalloc1(len, is);CHKERRQ(ierr);
256     ierr = DMGetDefaultGlobalSection(*superdm, &supersectionGlobal);CHKERRQ(ierr);
257     for (i = 0 ; i < len; startf += Nfs[i], ++i) {
258       PetscInt *subIndices;
259       PetscInt  subSize, subOff, pStart, pEnd, p, start, end, dummy;
260 
261       ierr = PetscSectionGetChart(sectionGlobals[i], &pStart, &pEnd);CHKERRQ(ierr);
262       ierr = PetscSectionGetConstrainedStorageSize(sectionGlobals[i], &subSize);CHKERRQ(ierr);
263       ierr = PetscMalloc1(subSize, &subIndices);CHKERRQ(ierr);
264       for (p = pStart, subOff = 0; p < pEnd; ++p) {
265         PetscInt gdof, gcdof, gtdof, d;
266 
267         ierr = PetscSectionGetDof(sectionGlobals[i], p, &gdof);CHKERRQ(ierr);
268         ierr = PetscSectionGetConstraintDof(sections[i], p, &gcdof);CHKERRQ(ierr);
269         gtdof = gdof - gcdof;
270         if (gdof > 0 && gtdof) {
271           if (bs < 0)           {bs = gtdof;}
272           else if (bs != gtdof) {bs = 1;}
273           ierr = DMGetGlobalFieldOffset_Private(*superdm, p, startf, &start, &dummy);CHKERRQ(ierr);
274           ierr = DMGetGlobalFieldOffset_Private(*superdm, p, startf+Nfs[i]-1, &dummy, &end);CHKERRQ(ierr);
275           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);
276           for (d = start; d < end; ++d, ++subOff) subIndices[subOff] = d;
277         }
278       }
279       ierr = ISCreateGeneral(comm, subSize, subIndices, PETSC_OWN_POINTER, &(*is)[i]);CHKERRQ(ierr);
280       /* Must have same blocksize on all procs (some might have no points) */
281       {
282         PetscInt bs = -1, bsLocal[2], bsMinMax[2];
283 
284         bsLocal[0] = bs < 0 ? PETSC_MAX_INT : bs; bsLocal[1] = bs;
285         ierr = PetscGlobalMinMaxInt(comm, bsLocal, bsMinMax);CHKERRQ(ierr);
286         if (bsMinMax[0] != bsMinMax[1]) {bs = 1;}
287         else                            {bs = bsMinMax[0];}
288         ierr = ISSetBlockSize((*is)[i], bs);CHKERRQ(ierr);
289       }
290     }
291   }
292   /* Preserve discretizations */
293   if (len && dms[0]->prob) {
294     ierr = DMSetNumFields(*superdm, Nf);CHKERRQ(ierr);
295     for (i = 0, supf = 0; i < len; ++i) {
296       for (f = 0; f < Nfs[i]; ++f, ++supf) {
297         PetscObject disc;
298 
299         ierr = DMGetField(dms[i], f, &disc);CHKERRQ(ierr);
300         ierr = DMSetField(*superdm, supf, disc);CHKERRQ(ierr);
301       }
302     }
303   }
304   /* Preserve nullspaces */
305   for (i = 0, supf = 0; i < len; ++i) {
306     for (f = 0; f < Nfs[i]; ++f, ++supf) {
307       (*superdm)->nullspaceConstructors[supf] = dms[i]->nullspaceConstructors[f];
308       if ((*superdm)->nullspaceConstructors[supf]) {
309         haveNull = PETSC_TRUE;
310         nullf    = supf;
311       }
312     }
313   }
314   /* Attach nullspace to IS */
315   if (haveNull && is) {
316     MatNullSpace nullSpace;
317 
318     ierr = (*(*superdm)->nullspaceConstructors[nullf])(*superdm, nullf, &nullSpace);CHKERRQ(ierr);
319     ierr = PetscObjectCompose((PetscObject) (*is)[nullf], "nullspace", (PetscObject) nullSpace);CHKERRQ(ierr);
320     ierr = MatNullSpaceDestroy(&nullSpace);CHKERRQ(ierr);
321   }
322   ierr = PetscSectionDestroy(&supersection);CHKERRQ(ierr);
323   ierr = PetscFree3(Nfs, sections, sectionGlobals);CHKERRQ(ierr);
324   PetscFunctionReturn(0);
325 }
326