Actual source code: dmmbmg.cxx

petsc-3.10.3 2018-12-18
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  1:  #include <petsc/private/dmmbimpl.h>
  2:  #include <petscdmmoab.h>
  3: #include <MBTagConventions.hpp>
  4: #include <moab/NestedRefine.hpp>

  6: /*@
  7:   DMMoabGenerateHierarchy - Generate a multi-level uniform refinement hierarchy
  8:   by succesively refining a coarse mesh, already defined in the DM object
  9:   provided by the user.

 11:   Collective on MPI_Comm

 13:   Input Parameter:
 14: + dmb  - The DMMoab object

 16:   Output Parameter:
 17: + nlevels   - The number of levels of refinement needed to generate the hierarchy
 18: . ldegrees  - The degree of refinement at each level in the hierarchy

 20:   Level: beginner

 22: .keywords: DMMoab, create, refinement
 23: @*/
 24: PetscErrorCode DMMoabGenerateHierarchy(DM dm, PetscInt nlevels, PetscInt *ldegrees)
 25: {
 26:   DM_Moab        *dmmoab;
 27:   PetscErrorCode  ierr;
 28:   moab::ErrorCode merr;
 29:   PetscInt *pdegrees, ilevel;
 30:   std::vector<moab::EntityHandle> hsets;

 34:   dmmoab = (DM_Moab*)(dm)->data;

 36:   if (!ldegrees) {
 37:     PetscMalloc1(nlevels, &pdegrees);
 38:     for (ilevel = 0; ilevel < nlevels; ilevel++) pdegrees[ilevel] = 2; /* default = Degree 2 refinement */
 39:   }
 40:   else pdegrees = ldegrees;

 42:   /* initialize set level refinement data for hierarchy */
 43:   dmmoab->nhlevels = nlevels;

 45:   /* Instantiate the nested refinement class */
 46: #ifdef MOAB_HAVE_MPI
 47:   dmmoab->hierarchy = new moab::NestedRefine(dynamic_cast<moab::Core*>(dmmoab->mbiface), dmmoab->pcomm, dmmoab->fileset);
 48: #else
 49:   dmmoab->hierarchy = new moab::NestedRefine(dynamic_cast<moab::Core*>(dmmoab->mbiface), NULL, dmmoab->fileset);
 50: #endif

 52:   PetscMalloc1(nlevels + 1, &dmmoab->hsets);

 54:   /* generate the mesh hierarchy */
 55:   merr = dmmoab->hierarchy->generate_mesh_hierarchy(nlevels, pdegrees, hsets, false);MBERRNM(merr);

 57: #ifdef MOAB_HAVE_MPI
 58:   if (dmmoab->pcomm->size() > 1) {
 59:     merr = dmmoab->hierarchy->exchange_ghosts(hsets, dmmoab->nghostrings);MBERRNM(merr);
 60:   }
 61: #endif

 63:   /* copy the mesh sets for nested refinement hierarchy */
 64:   dmmoab->hsets[0] = hsets[0];
 65:   for (ilevel = 1; ilevel <= nlevels; ilevel++)
 66:   {
 67:     dmmoab->hsets[ilevel] = hsets[ilevel];

 69: #ifdef MOAB_HAVE_MPI
 70:     merr = dmmoab->pcomm->assign_global_ids(hsets[ilevel], dmmoab->dim, 0, false, true, false);MBERRNM(merr);
 71: #endif

 73:     /* Update material and other geometric tags from parent to child sets */
 74:     merr = dmmoab->hierarchy->update_special_tags(ilevel, hsets[ilevel]);MBERRNM(merr);
 75:   }

 77:   hsets.clear();
 78:   if (!ldegrees) {
 79:     PetscFree(pdegrees);
 80:   }
 81:   return(0);
 82: }

 84: /*@
 85:   DMRefineHierarchy_Moab - Generate a multi-level DM hierarchy
 86:   by succesively refining a coarse mesh.

 88:   Collective on MPI_Comm

 90:   Input Parameter:
 91: + dm  - The DMMoab object

 93:   Output Parameter:
 94: + nlevels   - The number of levels of refinement needed to generate the hierarchy
 95: . dmf  - The DM objects after successive refinement of the hierarchy

 97:   Level: beginner

 99: .keywords: DMMoab, generate, refinement
100: @*/
101: PETSC_EXTERN PetscErrorCode  DMRefineHierarchy_Moab(DM dm, PetscInt nlevels, DM dmf[])
102: {
103:   PetscErrorCode  ierr;
104:   PetscInt        i;


108:   DMRefine(dm, PetscObjectComm((PetscObject)dm), &dmf[0]);
109:   for (i = 1; i < nlevels; i++) {
110:     DMRefine(dmf[i - 1], PetscObjectComm((PetscObject)dm), &dmf[i]);
111:   }
112:   return(0);
113: }

115: /*@
116:   DMCoarsenHierarchy_Moab - Generate a multi-level DM hierarchy
117:   by succesively coarsening a refined mesh.

119:   Collective on MPI_Comm

121:   Input Parameter:
122: + dm  - The DMMoab object

124:   Output Parameter:
125: + nlevels   - The number of levels of refinement needed to generate the hierarchy
126: . dmc  - The DM objects after successive coarsening of the hierarchy

128:   Level: beginner

130: .keywords: DMMoab, generate, coarsening
131: @*/
132: PETSC_EXTERN PetscErrorCode DMCoarsenHierarchy_Moab(DM dm, PetscInt nlevels, DM dmc[])
133: {
134:   PetscErrorCode  ierr;
135:   PetscInt        i;


139:   DMCoarsen(dm, PetscObjectComm((PetscObject)dm), &dmc[0]);
140:   for (i = 1; i < nlevels; i++) {
141:     DMCoarsen(dmc[i - 1], PetscObjectComm((PetscObject)dm), &dmc[i]);
142:   }
143:   return(0);
144: }

146: PETSC_EXTERN PetscErrorCode DMMoab_Compute_NNZ_From_Connectivity(DM, PetscInt*, PetscInt*, PetscInt*, PetscInt*, PetscBool);

148: /*@
149:   DMCreateInterpolation_Moab - Generate the interpolation operators to transform
150:   operators (matrices, vectors) from parent level to child level as defined by
151:   the DM inputs provided by the user.

153:   Collective on MPI_Comm

155:   Input Parameter:
156: + dm1  - The DMMoab object
157: - dm2  - the second, finer DMMoab object

159:   Output Parameter:
160: + interpl  - The interpolation operator for transferring data between the levels
161: - vec      - The scaling vector (optional)

163:   Level: developer

165: .keywords: DMMoab, create, refinement
166: @*/
167: PETSC_EXTERN PetscErrorCode DMCreateInterpolation_Moab(DM dmp, DM dmc, Mat* interpl, Vec* vec)
168: {
169:   DM_Moab         *dmbp, *dmbc;
170:   PetscErrorCode   ierr;
171:   moab::ErrorCode  merr;
172:   PetscInt         dim;
173:   PetscReal        factor;
174:   PetscInt         innz, *nnz, ionz, *onz;
175:   PetscInt         nlsizp, nlsizc, nlghsizp, ngsizp, ngsizc;
176:   const PetscBool  use_consistent_bases=PETSC_TRUE;

181:   dmbp = (DM_Moab*)(dmp)->data;
182:   dmbc = (DM_Moab*)(dmc)->data;
183:   nlsizp = dmbp->nloc;// *dmb1->numFields;
184:   nlsizc = dmbc->nloc;// *dmb2->numFields;
185:   ngsizp = dmbp->n; // *dmb1->numFields;
186:   ngsizc = dmbc->n; // *dmb2->numFields;
187:   nlghsizp = (dmbp->nloc + dmbp->nghost); // *dmb1->numFields;

189:   // Columns = Parent DoFs ;  Rows = Child DoFs
190:   // Interpolation matrix: \sum_{i=1}^P Owned(Child) * (Owned(Parent) + Ghosted(Parent))
191:   // Size: nlsizc * nlghsizp
192:   PetscInfo4(NULL, "Creating interpolation matrix %D X %D to apply transformation between levels %D -> %D.\n", ngsizc, nlghsizp, dmbp->hlevel, dmbc->hlevel);

194:   DMGetDimension(dmp, &dim);

196:   /* allocate the nnz, onz arrays based on block size and local nodes */
197:   PetscCalloc2(nlsizc, &nnz, nlsizc, &onz);

199:   /* Loop through the local elements and compute the relation between the current parent and the refined_level. */
200:   for (moab::Range::iterator iter = dmbc->vowned->begin(); iter != dmbc->vowned->end(); iter++) {

202:     const moab::EntityHandle vhandle = *iter;
203:     /* define local variables */
204:     moab::EntityHandle parent;
205:     std::vector<moab::EntityHandle> adjs;
206:     moab::Range     found;

208:     /* store the vertex DoF number */
209:     const int ldof = dmbc->lidmap[vhandle - dmbc->seqstart];

211:     /* Get adjacency information for current vertex - i.e., all elements of dimension (dim) that connects
212:        to the current vertex. We can then decipher if a vertex is ghosted or not and compute the
213:        non-zero pattern accordingly. */
214:     merr = dmbc->hierarchy->get_adjacencies(vhandle, dmbc->dim, adjs);MBERRNM(merr);

216:     /* loop over vertices and update the number of connectivity */
217:     for (unsigned jter = 0; jter < adjs.size(); jter++) {

219:       const moab::EntityHandle jhandle = adjs[jter];

221:       /* Get the relation between the current (coarse) parent and its corresponding (finer) children elements */
222:       merr = dmbc->hierarchy->child_to_parent(jhandle, dmbc->hlevel, dmbp->hlevel, &parent);MBERRNM(merr);

224:       /* Get connectivity information in canonical ordering for the local element */
225:       std::vector<moab::EntityHandle> connp;
226:       merr = dmbp->hierarchy->get_connectivity(parent, dmbp->hlevel, connp);MBERRNM(merr);

228:       for (unsigned ic=0; ic < connp.size(); ++ic) {

230:         /* loop over each element connected to the adjacent vertex and update as needed */
231:         /* find the truly user-expected layer of ghosted entities to decipher NNZ pattern */
232:         if (found.find(connp[ic]) != found.end()) continue; /* make sure we don't double count shared vertices */
233:         if (dmbp->vghost->find(connp[ic]) != dmbp->vghost->end()) onz[ldof]++; /* update out-of-proc onz */
234:         else nnz[ldof]++; /* else local vertex */
235:         found.insert(connp[ic]);
236:       }
237:     }
238:   }

240:   for (int i = 0; i < nlsizc; i++)
241:     nnz[i] += 1; /* self count the node */

243:   ionz = onz[0];
244:   innz = nnz[0];
245:   for (int tc = 0; tc < nlsizc; tc++) {
246:     // check for maximum allowed sparsity = fully dense
247:     nnz[tc] = std::min(nlsizp, nnz[tc]);
248:     onz[tc] = std::min(ngsizp - nlsizp, onz[tc]);

250:     PetscInfo3(NULL, "  %d: NNZ = %d, ONZ = %d\n", tc, nnz[tc], onz[tc]);

252:     innz = (innz < nnz[tc] ? nnz[tc] : innz);
253:     ionz = (ionz < onz[tc] ? onz[tc] : ionz);
254:   }

256:   /* create interpolation matrix */
257:   MatCreate(PetscObjectComm((PetscObject)dmc), interpl);
258:   MatSetSizes(*interpl, nlsizc, nlsizp, ngsizc, ngsizp);
259:   MatSetType(*interpl, MATAIJ);
260:   MatSetFromOptions(*interpl);

262:   MatSeqAIJSetPreallocation(*interpl, innz, nnz);
263:   MatMPIAIJSetPreallocation(*interpl, innz, nnz, ionz, onz);

265:   /* clean up temporary memory */
266:   PetscFree2(nnz, onz);

268:   /* set up internal matrix data-structures */
269:   MatSetUp(*interpl);

271:   /* Define variables for assembly */
272:   std::vector<moab::EntityHandle> children;
273:   std::vector<moab::EntityHandle> connp, connc;
274:   std::vector<PetscReal> pcoords, ccoords, values_phi;

276:   if (use_consistent_bases) {
277:     const moab::EntityHandle ehandle = dmbp->elocal->front();

279:     merr = dmbp->hierarchy->parent_to_child(ehandle, dmbp->hlevel, dmbc->hlevel, children);MBERRNM(merr);

281:     /* Get connectivity and coordinates of the parent vertices */
282:     merr = dmbp->hierarchy->get_connectivity(ehandle, dmbp->hlevel, connp);MBERRNM(merr);
283:     merr = dmbc->mbiface->get_connectivity(&children[0], children.size(), connc);MBERRNM(merr);

285:     std::vector<PetscReal> natparam(3*connc.size(), 0.0);
286:     pcoords.resize(connp.size() * 3);
287:     ccoords.resize(connc.size() * 3);
288:     values_phi.resize(connp.size()*connc.size());
289:     /* Get coordinates for connectivity entities in canonical order for both coarse and finer levels */
290:     merr = dmbp->hierarchy->get_coordinates(&connp[0], connp.size(), dmbp->hlevel, &pcoords[0]);MBERRNM(merr);
291:     merr = dmbc->hierarchy->get_coordinates(&connc[0], connc.size(), dmbc->hlevel, &ccoords[0]);MBERRNM(merr);

293:     /* Set values: For each DOF in coarse grid cell, set the contribution or PHI evaluated at each fine grid DOF point */
294:     for (unsigned tc = 0; tc < connc.size(); tc++) {
295:       const PetscInt offset = tc * 3;

297:       /* Scale ccoords relative to pcoords */
298:       DMMoabPToRMapping(dim, connp.size(), &pcoords[0], &ccoords[offset], &natparam[offset], &values_phi[connp.size()*tc]);
299:     }
300:   }
301:   else {
302:     factor = std::pow(2.0 /*degree_P_for_refinement*/, (dmbc->hlevel - dmbp->hlevel) * dmbp->dim * 1.0);
303:   }

305:   /* TODO: Decipher the correct non-zero pattern. There is still some issue with onz allocation */
306:   MatSetOption(*interpl, MAT_NEW_NONZERO_ALLOCATION_ERR, PETSC_FALSE);

308:   /* Loop through the remaining vertices. These vertices appear only on the current refined_level. */
309:   for (moab::Range::iterator iter = dmbp->elocal->begin(); iter != dmbp->elocal->end(); iter++) {

311:     const moab::EntityHandle ehandle = *iter;

313:     /* Get the relation between the current (coarse) parent and its corresponding (finer) children elements */
314:     children.clear();
315:     connc.clear();
316:     merr = dmbp->hierarchy->parent_to_child(ehandle, dmbp->hlevel, dmbc->hlevel, children);MBERRNM(merr);

318:     /* Get connectivity and coordinates of the parent vertices */
319:     merr = dmbp->hierarchy->get_connectivity(ehandle, dmbp->hlevel, connp);MBERRNM(merr);
320:     merr = dmbc->mbiface->get_connectivity(&children[0], children.size(), connc);MBERRNM(merr);

322:     pcoords.resize(connp.size() * 3);
323:     ccoords.resize(connc.size() * 3);
324:     /* Get coordinates for connectivity entities in canonical order for both coarse and finer levels */
325:     merr = dmbp->hierarchy->get_coordinates(&connp[0], connp.size(), dmbp->hlevel, &pcoords[0]);MBERRNM(merr);
326:     merr = dmbc->hierarchy->get_coordinates(&connc[0], connc.size(), dmbc->hlevel, &ccoords[0]);MBERRNM(merr);

328:     std::vector<int> dofsp(connp.size()), dofsc(connc.size());
329:     /* TODO: specific to scalar system - use GetDofs */
330:     DMMoabGetDofsBlocked(dmp, connp.size(), &connp[0], &dofsp[0]);
331:     DMMoabGetDofsBlocked(dmc, connc.size(), &connc[0], &dofsc[0]);

333:     /* Compute the actual interpolation weights when projecting solution/residual between levels */
334:     if (use_consistent_bases) {

336:       /* Use the cached values of natural parameteric coordinates and basis pre-evaluated.
337:          We are making an assumption here that UMR used in GMG to generate the hierarchy uses
338:          the same template for all elements; This will fail for mixed element meshes (TRI/QUAD).

340:          TODO: Fix the above assumption by caching data for families (especially for Tets and mixed meshes)
341:       */

343:       /* Set values: For each DOF in coarse grid cell, set the contribution or PHI evaluated at each fine grid DOF point */
344:       for (unsigned tc = 0; tc < connc.size(); tc++) {
345:         /* TODO: Check if we should be using INSERT_VALUES instead */
346:         MatSetValues(*interpl, 1, &dofsc[tc], connp.size(), &dofsp[0], &values_phi[connp.size()*tc], ADD_VALUES);
347:       }
348:     }
349:     else {
350:       /* Compute the interpolation weights by determining distance of 1-ring
351:          neighbor vertices from current vertex

353:          This should be used only when FEM basis is not used for the discretization.
354:          Else, the consistent interface to compute the basis function for interpolation
355:          between the levels should be evaluated correctly to preserve convergence of GMG.
356:          Shephard's basis will be terrible for any unsmooth problems.
357:       */
358:       values_phi.resize(connp.size());
359:       for (unsigned tc = 0; tc < connc.size(); tc++) {

361:         PetscReal normsum = 0.0;
362:         for (unsigned tp = 0; tp < connp.size(); tp++) {
363:           values_phi[tp] = 0.0;
364:           for (unsigned k = 0; k < 3; k++)
365:             values_phi[tp] += std::pow(pcoords[tp * 3 + k] - ccoords[k + tc * 3], dim);
366:           if (values_phi[tp] < 1e-12) {
367:             values_phi[tp] = 1e12;
368:           }
369:           else {
370:             //values_phi[tp] = std::pow(values_phi[tp], -1.0/dim);
371:             values_phi[tp] = std::pow(values_phi[tp], -1.0);
372:             normsum += values_phi[tp];
373:           }
374:         }
375:         for (unsigned tp = 0; tp < connp.size(); tp++) {
376:           if (values_phi[tp] > 1e11)
377:             values_phi[tp] = factor * 0.5 / connp.size();
378:           else
379:             values_phi[tp] = factor * values_phi[tp] * 0.5 / (connp.size() * normsum);
380:         }
381:         MatSetValues(*interpl, 1, &dofsc[tc], connp.size(), &dofsp[0], &values_phi[0], ADD_VALUES);
382:       }
383:     }
384:   }
385:   if (vec) *vec = NULL;
386:   MatAssemblyBegin(*interpl, MAT_FINAL_ASSEMBLY);
387:   MatAssemblyEnd(*interpl, MAT_FINAL_ASSEMBLY);
388:   return(0);
389: }

391: /*@
392:   DMCreateInjection_Moab - Generate a multi-level uniform refinement hierarchy
393:   by succesively refining a coarse mesh, already defined in the DM object
394:   provided by the user.

396:   Collective on MPI_Comm

398:   Input Parameter:
399: . dmb  - The DMMoab object

401:   Output Parameter:
402: . nlevels   - The number of levels of refinement needed to generate the hierarchy
403: + ldegrees  - The degree of refinement at each level in the hierarchy

405:   Level: beginner

407: .keywords: DMMoab, create, refinement
408: @*/
409: PETSC_EXTERN PetscErrorCode DMCreateInjection_Moab(DM dm1, DM dm2, VecScatter* ctx)
410: {
411:   //DM_Moab        *dmmoab;

416:   //dmmoab = (DM_Moab*)(dm1)->data;

418:   PetscPrintf(PETSC_COMM_WORLD, "[DMCreateInjection_Moab] :: Placeholder\n");
419:   return(0);
420: }

422: static PetscErrorCode DMMoab_UMR_Private(DM dm, MPI_Comm comm, PetscBool refine, DM *dmref)
423: {
424:   PetscErrorCode  ierr;
425:   PetscInt        i, dim;
426:   DM              dm2;
427:   moab::ErrorCode merr;
428:   DM_Moab        *dmb = (DM_Moab*)dm->data, *dd2;


434:   if ( (dmb->hlevel == dmb->nhlevels && refine) || (dmb->hlevel == 0 && !refine) ) {
435:     if (dmb->hlevel + 1 > dmb->nhlevels && refine) PetscInfo2(NULL, "Invalid multigrid refinement hierarchy level specified (%D). MOAB UMR max levels = %D. Creating a NULL object.\n", dmb->hlevel + 1, dmb->nhlevels);
436:     if (dmb->hlevel - 1 < 0 && !refine) PetscInfo1(NULL, "Invalid multigrid coarsen hierarchy level specified (%D). Creating a NULL object.\n", dmb->hlevel - 1);
437:     *dmref = PETSC_NULL;
438:     return(0);
439:   }

441:   DMMoabCreate(PetscObjectComm((PetscObject)dm), &dm2);
442:   dd2 = (DM_Moab*)dm2->data;

444:   dd2->mbiface = dmb->mbiface;
445: #ifdef MOAB_HAVE_MPI
446:   dd2->pcomm = dmb->pcomm;
447: #endif
448:   dd2->icreatedinstance = PETSC_FALSE;
449:   dd2->nghostrings = dmb->nghostrings;

451:   /* set the new level based on refinement/coarsening */
452:   if (refine) {
453:     dd2->hlevel = dmb->hlevel + 1;
454:   }
455:   else {
456:     dd2->hlevel = dmb->hlevel - 1;
457:   }

459:   /* Copy the multilevel hierarchy pointers in MOAB */
460:   dd2->hierarchy = dmb->hierarchy;
461:   dd2->nhlevels = dmb->nhlevels;
462:   PetscMalloc1(dd2->nhlevels + 1, &dd2->hsets);
463:   for (i = 0; i <= dd2->nhlevels; i++) {
464:     dd2->hsets[i] = dmb->hsets[i];
465:   }
466:   dd2->fileset = dd2->hsets[dd2->hlevel];

468:   /* do the remaining initializations for DMMoab */
469:   dd2->bs = dmb->bs;
470:   dd2->numFields = dmb->numFields;
471:   dd2->rw_dbglevel = dmb->rw_dbglevel;
472:   dd2->partition_by_rank = dmb->partition_by_rank;
473:   PetscStrcpy(dd2->extra_read_options, dmb->extra_read_options);
474:   PetscStrcpy(dd2->extra_write_options, dmb->extra_write_options);
475:   dd2->read_mode = dmb->read_mode;
476:   dd2->write_mode = dmb->write_mode;

478:   /* set global ID tag handle */
479:   DMMoabSetLocalToGlobalTag(dm2, dmb->ltog_tag);

481:   merr = dd2->mbiface->tag_get_handle(MATERIAL_SET_TAG_NAME, dd2->material_tag);MBERRNM(merr);

483:   DMSetOptionsPrefix(dm2, ((PetscObject)dm)->prefix);
484:   DMGetDimension(dm, &dim);
485:   DMSetDimension(dm2, dim);

487:   /* allow overloaded (user replaced) operations to be inherited by refinement clones */
488:   dm2->ops->creatematrix = dm->ops->creatematrix;

490:   /* copy fill information if given */
491:   DMMoabSetBlockFills(dm2, dmb->dfill, dmb->ofill);

493:   /* copy vector type information */
494:   DMSetMatType(dm2, dm->mattype);
495:   DMSetVecType(dm2, dm->vectype);
496:   dd2->numFields = dmb->numFields;
497:   if (dmb->numFields) {
498:     DMMoabSetFieldNames(dm2, dmb->numFields, dmb->fieldNames);
499:   }

501:   DMSetFromOptions(dm2);

503:   /* recreate Dof numbering for the refined DM and make sure the distribution is correctly populated */
504:   DMSetUp(dm2);

506:   *dmref = dm2;
507:   return(0);
508: }


511: /*@
512:   DMRefine_Moab - Generate a multi-level uniform refinement hierarchy
513:   by succesively refining a coarse mesh, already defined in the DM object
514:   provided by the user.

516:   Collective on DM

518:   Input Parameter:
519: + dm  - The DMMoab object
520: - comm - the communicator to contain the new DM object (or MPI_COMM_NULL)

522:   Output Parameter:
523: . dmf - the refined DM, or NULL

525:   Note: If no refinement was done, the return value is NULL

527:   Level: developer

529: .keywords: DMMoab, create, refinement
530: @*/
531: PETSC_EXTERN PetscErrorCode DMRefine_Moab(DM dm, MPI_Comm comm, DM* dmf)
532: {
533:   PetscErrorCode  ierr;


538:   DMMoab_UMR_Private(dm, comm, PETSC_TRUE, dmf);
539:   return(0);
540: }

542: /*@
543:   DMCoarsen_Moab - Generate a multi-level uniform refinement hierarchy
544:   by succesively refining a coarse mesh, already defined in the DM object
545:   provided by the user.

547:   Collective on DM

549:   Input Parameter:
550: . dm  - The DMMoab object
551: - comm - the communicator to contain the new DM object (or MPI_COMM_NULL)

553:   Output Parameter:
554: . dmf - the coarsened DM, or NULL

556:   Note: If no coarsening was done, the return value is NULL

558:   Level: developer

560: .keywords: DMMoab, create, coarsening
561: @*/
562: PETSC_EXTERN PetscErrorCode DMCoarsen_Moab(DM dm, MPI_Comm comm, DM* dmc)
563: {
564:   PetscErrorCode  ierr;


569:   DMMoab_UMR_Private(dm, comm, PETSC_FALSE, dmc);
570:   return(0);
571: }