xref: /petsc/src/dm/interface/dmi.c (revision feff33ee0b5b037fa8f9f294dede656a2f85cc47)
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 = DMGetDefaultGlobalSection(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 = DMGetDefaultSection(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 = DMGetDefaultSection(dm, &section);CHKERRQ(ierr);
95   ierr = DMGetDefaultGlobalSection(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 = -1, bsLocal[2], bsMinMax[2];
102     ierr = PetscSectionGetChart(sectionGlobal, &pStart, &pEnd);CHKERRQ(ierr);
103     for (p = pStart; p < pEnd; ++p) {
104       PetscInt gdof, pSubSize  = 0;
105 
106       ierr = PetscSectionGetDof(sectionGlobal, p, &gdof);CHKERRQ(ierr);
107       if (gdof > 0) {
108         for (f = 0; f < numFields; ++f) {
109           PetscInt fdof, fcdof;
110 
111           ierr     = PetscSectionGetFieldDof(section, p, fields[f], &fdof);CHKERRQ(ierr);
112           ierr     = PetscSectionGetFieldConstraintDof(section, p, fields[f], &fcdof);CHKERRQ(ierr);
113           pSubSize += fdof-fcdof;
114         }
115         subSize += pSubSize;
116         if (pSubSize) {
117           if (bs < 0) {
118             bs = pSubSize;
119           } else if (bs != pSubSize) {
120             /* Layout does not admit a pointwise block size */
121             bs = 1;
122           }
123         }
124       }
125     }
126     /* Must have same blocksize on all procs (some might have no points) */
127     bsLocal[0] = bs < 0 ? PETSC_MAX_INT : bs; bsLocal[1] = bs;
128     ierr = PetscGlobalMinMaxInt(PetscObjectComm((PetscObject) dm), bsLocal, bsMinMax);CHKERRQ(ierr);
129     if (bsMinMax[0] != bsMinMax[1]) {bs = 1;}
130     else                            {bs = bsMinMax[0];}
131     ierr = PetscMalloc1(subSize, &subIndices);CHKERRQ(ierr);
132     for (p = pStart; p < pEnd; ++p) {
133       PetscInt gdof, goff;
134 
135       ierr = PetscSectionGetDof(sectionGlobal, p, &gdof);CHKERRQ(ierr);
136       if (gdof > 0) {
137         ierr = PetscSectionGetOffset(sectionGlobal, p, &goff);CHKERRQ(ierr);
138         for (f = 0; f < numFields; ++f) {
139           PetscInt fdof, fcdof, fc, f2, poff = 0;
140 
141           /* Can get rid of this loop by storing field information in the global section */
142           for (f2 = 0; f2 < fields[f]; ++f2) {
143             ierr  = PetscSectionGetFieldDof(section, p, f2, &fdof);CHKERRQ(ierr);
144             ierr  = PetscSectionGetFieldConstraintDof(section, p, f2, &fcdof);CHKERRQ(ierr);
145             poff += fdof-fcdof;
146           }
147           ierr = PetscSectionGetFieldDof(section, p, fields[f], &fdof);CHKERRQ(ierr);
148           ierr = PetscSectionGetFieldConstraintDof(section, p, fields[f], &fcdof);CHKERRQ(ierr);
149           for (fc = 0; fc < fdof-fcdof; ++fc, ++subOff) {
150             subIndices[subOff] = goff+poff+fc;
151           }
152         }
153       }
154     }
155     ierr = ISCreateGeneral(PetscObjectComm((PetscObject)dm), subSize, subIndices, PETSC_OWN_POINTER, is);CHKERRQ(ierr);
156     if (bs > 1) {
157       /* We need to check that the block size does not come from non-contiguous fields */
158       PetscInt i, j, set = 1;
159       for (i = 0; i < subSize; i += bs) {
160         for (j = 0; j < bs; ++j) {
161           if (subIndices[i+j] != subIndices[i]+j) {set = 0; break;}
162         }
163       }
164       if (set) {ierr = ISSetBlockSize(*is, bs);CHKERRQ(ierr);}
165     }
166   }
167   if (subdm) {
168     PetscSection subsection;
169     PetscBool    haveNull = PETSC_FALSE;
170     PetscInt     f, nf = 0;
171 
172     ierr = PetscSectionCreateSubsection(section, numFields, fields, &subsection);CHKERRQ(ierr);
173     ierr = DMSetDefaultSection(*subdm, subsection);CHKERRQ(ierr);
174     ierr = PetscSectionDestroy(&subsection);CHKERRQ(ierr);
175     for (f = 0; f < numFields; ++f) {
176       (*subdm)->nullspaceConstructors[f] = dm->nullspaceConstructors[fields[f]];
177       if ((*subdm)->nullspaceConstructors[f]) {
178         haveNull = PETSC_TRUE;
179         nf       = f;
180       }
181     }
182     if (haveNull && is) {
183       MatNullSpace nullSpace;
184 
185       ierr = (*(*subdm)->nullspaceConstructors[nf])(*subdm, nf, &nullSpace);CHKERRQ(ierr);
186       ierr = PetscObjectCompose((PetscObject) *is, "nullspace", (PetscObject) nullSpace);CHKERRQ(ierr);
187       ierr = MatNullSpaceDestroy(&nullSpace);CHKERRQ(ierr);
188     }
189     if (dm->prob) {
190       PetscInt Nf;
191 
192       ierr = PetscDSGetNumFields(dm->prob, &Nf);CHKERRQ(ierr);
193       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);
194       ierr = DMSetNumFields(*subdm, numFields);CHKERRQ(ierr);
195       for (f = 0; f < numFields; ++f) {
196         PetscObject disc;
197 
198         ierr = DMGetField(dm, fields[f], &disc);CHKERRQ(ierr);
199         ierr = DMSetField(*subdm, f, disc);CHKERRQ(ierr);
200       }
201       if (numFields == 1 && is) {
202         PetscObject disc, space, pmat;
203 
204         ierr = DMGetField(*subdm, 0, &disc);CHKERRQ(ierr);
205         ierr = PetscObjectQuery(disc, "nullspace", &space);CHKERRQ(ierr);
206         if (space) {ierr = PetscObjectCompose((PetscObject) *is, "nullspace", space);CHKERRQ(ierr);}
207         ierr = PetscObjectQuery(disc, "nearnullspace", &space);CHKERRQ(ierr);
208         if (space) {ierr = PetscObjectCompose((PetscObject) *is, "nearnullspace", space);CHKERRQ(ierr);}
209         ierr = PetscObjectQuery(disc, "pmat", &pmat);CHKERRQ(ierr);
210         if (pmat) {ierr = PetscObjectCompose((PetscObject) *is, "pmat", pmat);CHKERRQ(ierr);}
211       }
212     }
213   }
214   PetscFunctionReturn(0);
215 }
216 
217 /* This assumes that the DM has been cloned prior to the call */
218 PetscErrorCode DMCreateSuperDM_Section_Private(DM dms[], PetscInt len, IS **is, DM *superdm)
219 {
220   PetscSection  *sections, *sectionGlobals;
221   PetscInt      *Nfs, Nf = 0, *subIndices, i;
222   PetscErrorCode ierr;
223 
224   PetscFunctionBegin;
225   ierr = PetscMalloc3(len, &Nfs, len, &sections, len, &sectionGlobals);CHKERRQ(ierr);
226   for (i = 0 ; i < len; ++i) {
227     ierr = DMGetDefaultSection(dms[i], &sections[i]);CHKERRQ(ierr);
228     ierr = DMGetDefaultGlobalSection(dms[i], &sectionGlobals[i]);CHKERRQ(ierr);
229     if (!sections[i]) SETERRQ(PetscObjectComm((PetscObject)dms[0]), PETSC_ERR_ARG_WRONG, "Must set default section for DM before splitting fields");
230     if (!sectionGlobals[i]) SETERRQ(PetscObjectComm((PetscObject)dms[0]), PETSC_ERR_ARG_WRONG, "Must set default global section for DM before splitting fields");
231     ierr = PetscSectionGetNumFields(sections[i], &Nfs[i]);CHKERRQ(ierr);
232     Nf += Nfs[i];
233   }
234   if (is) {
235     PetscInt *offs, *globalOffs, iOff = 0;
236 
237     ierr = PetscMalloc1(len, is);CHKERRQ(ierr);
238     ierr = PetscCalloc2(len+1, &offs, len+1, &globalOffs);CHKERRQ(ierr);
239     for (i = 0 ; i < len; ++i) {
240       ierr = PetscSectionGetConstrainedStorageSize(sectionGlobals[i], &offs[i]);CHKERRQ(ierr);
241       offs[len] += offs[i];
242     }
243     ierr = MPI_Scan(offs, globalOffs, len+1, MPIU_INT, MPI_SUM, PetscObjectComm((PetscObject) dms[0]));CHKERRQ(ierr);
244     for (i = 0 ; i <= len; ++i) globalOffs[i] -= offs[i];
245     for (i = 0 ; i < len; ++i, iOff += offs[i-1]) {
246       PetscInt bs = -1, bsLocal[2], bsMinMax[2];
247       PetscInt subSize = 0, subOff = 0, gtoff = globalOffs[len] - globalOffs[i], pStart, pEnd, p;
248 
249       ierr = PetscSectionGetChart(sectionGlobals[i], &pStart, &pEnd);CHKERRQ(ierr);
250       ierr = PetscSectionGetConstrainedStorageSize(sectionGlobals[i], &subSize);CHKERRQ(ierr);
251       ierr = PetscMalloc1(subSize, &subIndices);CHKERRQ(ierr);
252       for (p = pStart; p < pEnd; ++p) {
253         PetscInt gdof, gcdof, gtdof, goff, d;
254 
255         ierr = PetscSectionGetDof(sectionGlobals[i], p, &gdof);CHKERRQ(ierr);
256         ierr = PetscSectionGetConstraintDof(sections[i], p, &gcdof);CHKERRQ(ierr);
257         gtdof = gdof-gcdof;
258         if (gdof > 0 && gtdof) {
259           if (bs < 0)           {bs = gtdof;}
260           else if (bs != gtdof) {bs = 1;}
261           ierr = PetscSectionGetOffset(sectionGlobals[i], p, &goff);CHKERRQ(ierr);
262           for (d = 0; d < gtdof; ++d, ++subOff) {
263             subIndices[subOff] = goff+gtoff+d+iOff;
264           }
265         }
266       }
267       ierr = ISCreateGeneral(PetscObjectComm((PetscObject) dms[0]), subSize, subIndices, PETSC_OWN_POINTER, &(*is)[i]);CHKERRQ(ierr);
268       /* Must have same blocksize on all procs (some might have no points) */
269       bsLocal[0] = bs < 0 ? PETSC_MAX_INT : bs; bsLocal[1] = bs;
270       ierr = PetscGlobalMinMaxInt(PetscObjectComm((PetscObject) dms[0]), bsLocal, bsMinMax);CHKERRQ(ierr);
271       if (bsMinMax[0] != bsMinMax[1]) {bs = 1;}
272       else                            {bs = bsMinMax[0];}
273       ierr = ISSetBlockSize((*is)[i], bs);CHKERRQ(ierr);
274     }
275     ierr = PetscFree2(offs, globalOffs);CHKERRQ(ierr);
276   }
277   if (superdm) {
278     PetscSection supersection;
279     PetscBool    haveNull = PETSC_FALSE;
280     PetscInt     field, f, nf = 0;
281 
282     ierr = PetscSectionCreateSupersection(sections, len, &supersection);CHKERRQ(ierr);
283     ierr = DMSetDefaultSection(*superdm, supersection);CHKERRQ(ierr);
284     ierr = PetscSectionDestroy(&supersection);CHKERRQ(ierr);
285     for (i = 0, field = 0; i < len; ++i) {
286       for (f = 0; f < Nfs[i]; ++f, ++field) {
287         (*superdm)->nullspaceConstructors[field] = dms[i]->nullspaceConstructors[f];
288         if ((*superdm)->nullspaceConstructors[field]) {
289           haveNull = PETSC_TRUE;
290           nf       = field;
291         }
292       }
293     }
294     if (haveNull && is) {
295       MatNullSpace nullSpace;
296 
297       ierr = (*(*superdm)->nullspaceConstructors[nf])(*superdm, nf, &nullSpace);CHKERRQ(ierr);
298       ierr = PetscObjectCompose((PetscObject) (*is)[nf], "nullspace", (PetscObject) nullSpace);CHKERRQ(ierr);
299       ierr = MatNullSpaceDestroy(&nullSpace);CHKERRQ(ierr);
300     }
301     if (len && dms[0]->prob) {
302       ierr = DMSetNumFields(*superdm, Nf);CHKERRQ(ierr);
303       for (i = 0, field = 0; i < len; ++i) {
304         for (f = 0; f < Nfs[i]; ++f, ++field) {
305           PetscObject disc;
306 
307           ierr = DMGetField(dms[i], f, &disc);CHKERRQ(ierr);
308           ierr = DMSetField(*superdm, field, disc);CHKERRQ(ierr);
309         }
310       }
311     }
312   }
313   ierr = PetscFree3(Nfs, sections, sectionGlobals);CHKERRQ(ierr);
314   PetscFunctionReturn(0);
315 }
316