Actual source code: stag.c

petsc-master 2020-09-18
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  1: /*
  2:    Implementation of DMStag, defining dimension-independent functions in the
  3:    DM API. stag1d.c, stag2d.c, and stag3d.c may include dimension-specific
  4:    implementations of DM API functions, and other files here contain additional
  5:    DMStag-specific API functions, as well as internal functions.
  6: */
  7: #include <petsc/private/dmstagimpl.h>
  8: #include <petscsf.h>

 10: static PetscErrorCode DMClone_Stag(DM dm,DM *newdm)
 11: {

 15:   /* Destroy the DM created by generic logic in DMClone() */
 16:   if (*newdm) {
 17:     DMDestroy(newdm);
 18:   }
 19:   DMStagDuplicateWithoutSetup(dm,PetscObjectComm((PetscObject)dm),newdm);
 20:   DMSetUp(*newdm);
 21:   return(0);
 22: }

 24: static PetscErrorCode DMDestroy_Stag(DM dm)
 25: {
 27:   DM_Stag        *stag;
 28:   PetscInt       i;

 31:   stag = (DM_Stag*)dm->data;
 32:   for (i=0; i<DMSTAG_MAX_DIM; ++i) {
 33:     PetscFree(stag->l[i]);
 34:   }
 35:   VecScatterDestroy(&stag->gtol);
 36:   VecScatterDestroy(&stag->ltog_injective);
 37:   PetscFree(stag->neighbors);
 38:   PetscFree(stag->locationOffsets);
 39:   PetscFree(stag->coordinateDMType);
 40:   PetscFree(stag);
 41:   return(0);
 42: }

 44: static PetscErrorCode DMCreateGlobalVector_Stag(DM dm,Vec *vec)
 45: {
 46:   PetscErrorCode  ierr;
 47:   DM_Stag * const stag = (DM_Stag*)dm->data;

 50:   VecCreateMPI(PetscObjectComm((PetscObject)dm),stag->entries,PETSC_DECIDE,vec);
 51:   VecSetDM(*vec,dm);
 52:   /* Could set some ops, as DMDA does */
 53:   VecSetLocalToGlobalMapping(*vec,dm->ltogmap);
 54:   return(0);
 55: }

 57: static PetscErrorCode DMCreateLocalVector_Stag(DM dm,Vec *vec)
 58: {
 59:   PetscErrorCode  ierr;
 60:   DM_Stag * const stag = (DM_Stag*)dm->data;

 63:   VecCreateSeq(PETSC_COMM_SELF,stag->entriesGhost,vec);
 64:   VecSetBlockSize(*vec,stag->entriesPerElement);
 65:   VecSetDM(*vec,dm);
 66:   return(0);
 67: }

 69: static PetscErrorCode DMCreateMatrix_Stag(DM dm,Mat *mat)
 70: {
 71:   PetscErrorCode         ierr;
 72:   MatType                matType;
 73:   PetscBool              isaij,isshell;
 74:   PetscInt               entries,width,nNeighbors,dim,dof[DMSTAG_MAX_STRATA],stencilWidth;
 75:   DMStagStencilType      stencilType;
 76:   ISLocalToGlobalMapping ltogmap;

 79:   DMGetDimension(dm,&dim);
 80:   DMGetMatType(dm,&matType);
 81:   PetscStrcmp(matType,MATAIJ,&isaij);
 82:   PetscStrcmp(matType,MATSHELL,&isshell);
 83:   DMStagGetEntries(dm,&entries);
 84:   DMStagGetDOF(dm,&dof[0],&dof[1],&dof[2],&dof[3]);
 85:   DMStagGetStencilWidth(dm,&stencilWidth);
 86:   DMStagGetStencilType(dm,&stencilType);

 88:   if (isaij) {
 89:     /* This implementation gives a very dense stencil, which is likely unsuitable for
 90:        real applications. */
 91:     switch (stencilType) {
 92:       case DMSTAG_STENCIL_NONE:
 93:         nNeighbors = 1;
 94:         break;
 95:       case DMSTAG_STENCIL_STAR:
 96:         switch (dim) {
 97:           case 1 :
 98:             nNeighbors = 2*stencilWidth + 1;
 99:             break;
100:           case 2 :
101:             nNeighbors = 4*stencilWidth + 3;
102:             break;
103:           case 3 :
104:             nNeighbors = 6*stencilWidth + 5;
105:             break;
106:           default : SETERRQ1(PetscObjectComm((PetscObject)dm),PETSC_ERR_ARG_OUTOFRANGE,"Unsupported dimension %d",dim);
107:         }
108:         break;
109:       case DMSTAG_STENCIL_BOX:
110:         switch (dim) {
111:           case 1 :
112:             nNeighbors = (2*stencilWidth + 1);
113:             break;
114:           case 2 :
115:             nNeighbors = (2*stencilWidth + 1) * (2*stencilWidth + 1);
116:             break;
117:           case 3 :
118:             nNeighbors = (2*stencilWidth + 1) * (2*stencilWidth + 1) * (2*stencilWidth + 1);
119:             break;
120:           default : SETERRQ1(PetscObjectComm((PetscObject)dm),PETSC_ERR_ARG_OUTOFRANGE,"Unsupported dimension %d",dim);
121:         }
122:         break;
123:       default : SETERRQ(PetscObjectComm((PetscObject)dm),PETSC_ERR_ARG_OUTOFRANGE,"Unsupported stencil");
124:     }
125:     width = (dof[0] + dof[1] + dof[2] + dof[3]) * nNeighbors;
126:     MatCreateAIJ(PETSC_COMM_WORLD,entries,entries,PETSC_DETERMINE,PETSC_DETERMINE,width,NULL,width,NULL,mat);
127:   } else if (isshell) {
128:     MatCreate(PetscObjectComm((PetscObject)dm),mat);
129:     MatSetSizes(*mat,entries,entries,PETSC_DETERMINE,PETSC_DETERMINE);
130:     MatSetType(*mat,MATSHELL);
131:     MatSetUp(*mat);
132:   } else SETERRQ1(PETSC_COMM_WORLD,PETSC_ERR_SUP,"Not implemented for Mattype %s",matType);

134:   DMGetLocalToGlobalMapping(dm,&ltogmap);
135:   MatSetLocalToGlobalMapping(*mat,ltogmap,ltogmap);
136:   MatSetDM(*mat,dm);
137:   return(0);
138: }

140: static PetscErrorCode DMGetCompatibility_Stag(DM dm,DM dm2,PetscBool *compatible,PetscBool *set)
141: {
142:   PetscErrorCode  ierr;
143:   const DM_Stag * const stag  = (DM_Stag*)dm->data;
144:   const DM_Stag * const stag2 = (DM_Stag*)dm2->data;
145:   PetscInt              dim,dim2,i;
146:   MPI_Comm              comm;
147:   PetscMPIInt           sameComm;
148:   DMType                type2;
149:   PetscBool             sameType;

152:   DMGetType(dm2,&type2);
153:   PetscStrcmp(DMSTAG,type2,&sameType);
154:   if (!sameType) {
155:     PetscInfo1((PetscObject)dm,"DMStag compatibility check not implemented with DM of type %s\n",type2);
156:     *set = PETSC_FALSE;
157:     return(0);
158:   }

160:   PetscObjectGetComm((PetscObject)dm,&comm);
161:   MPI_Comm_compare(comm,PetscObjectComm((PetscObject)dm2),&sameComm);
162:   if (sameComm != MPI_IDENT) {
163:     PetscInfo2((PetscObject)dm,"DMStag objects have different communicators: %d != %d\n",comm,PetscObjectComm((PetscObject)dm2));
164:     *set = PETSC_FALSE;
165:     return(0);
166:   }
167:   DMGetDimension(dm ,&dim);
168:   DMGetDimension(dm2,&dim2);
169:   if (dim != dim2) {
170:     PetscInfo((PetscObject)dm,"DMStag objects have different dimensions");
171:     *set = PETSC_TRUE;
172:     *compatible = PETSC_FALSE;
173:     return(0);
174:   }
175:   for (i=0; i<dim; ++i) {
176:     if (stag->N[i] != stag2->N[i]) {
177:       PetscInfo3((PetscObject)dm,"DMStag objects have different global numbers of elements in dimension %D: %D != %D\n",i,stag->n[i],stag2->n[i]);
178:       *set = PETSC_TRUE;
179:       *compatible = PETSC_FALSE;
180:       return(0);
181:     }
182:     if (stag->n[i] != stag2->n[i]) {
183:       PetscInfo3((PetscObject)dm,"DMStag objects have different local numbers of elements in dimension %D: %D != %D\n",i,stag->n[i],stag2->n[i]);
184:       *set = PETSC_TRUE;
185:       *compatible = PETSC_FALSE;
186:       return(0);
187:     }
188:     if (stag->boundaryType[i] != stag2->boundaryType[i]) {
189:       PetscInfo3((PetscObject)dm,"DMStag objects have different boundary types in dimension %d: %s != %s\n",i,stag->boundaryType[i],stag2->boundaryType[i]);
190:       *set = PETSC_TRUE;
191:       *compatible = PETSC_FALSE;
192:       return(0);
193:     }
194:   }
195:   /* Note: we include stencil type and width in the notion of compatibility, as this affects
196:      the "atlas" (local subdomains). This might be irritating in legitimate cases
197:      of wanting to transfer between two other-wise compatible DMs with different
198:      stencil characteristics. */
199:   if (stag->stencilType != stag2->stencilType) {
200:     PetscInfo2((PetscObject)dm,"DMStag objects have different ghost stencil types: %s != %s\n",DMStagStencilTypes[stag->stencilType],DMStagStencilTypes[stag2->stencilType]);
201:     *set = PETSC_TRUE;
202:     *compatible = PETSC_FALSE;
203:     return(0);
204:   }
205:   if (stag->stencilWidth != stag2->stencilWidth) {
206:     PetscInfo2((PetscObject)dm,"DMStag objects have different ghost stencil widths: %D != %D\n",stag->stencilWidth,stag->stencilWidth);
207:     *set = PETSC_TRUE;
208:     *compatible = PETSC_FALSE;
209:     return(0);
210:   }
211:   *set = PETSC_TRUE;
212:   *compatible = PETSC_TRUE;
213:   return(0);
214: }


217: /*
218: Note there are several orderings in play here.
219: In all cases, non-element dof are associated with the element that they are below/left/behind, and the order in 2D proceeds vertex/bottom edge/left edge/element (with all dof on each together).
220: Also in all cases, only subdomains which are the last in their dimension have partial elements.

222: 1) "Natural" Ordering (not used). Number adding each full or partial (on the right or top) element, starting at the bottom left (i=0,j=0) and proceeding across the entire domain, row by row to get a global numbering.
223: 2) Global ("PETSc") ordering. The same as natural, but restricted to each domain. So, traverse all elements (again starting at the bottom left and going row-by-row) on rank 0, then continue numbering with rank 1, and so on.
224: 3) Local ordering. Including ghost elements (both interior and on the right/top/front to complete partial elements), use the same convention to create a local numbering.
225: */

227: static PetscErrorCode DMLocalToGlobalBegin_Stag(DM dm,Vec l,InsertMode mode,Vec g)
228: {
229:   PetscErrorCode  ierr;
230:   DM_Stag * const stag = (DM_Stag*)dm->data;

233:   if (mode == ADD_VALUES) {
234:     VecScatterBegin(stag->gtol,l,g,mode,SCATTER_REVERSE);
235:   } else if (mode == INSERT_VALUES) {
236:     if (stag->ltog_injective) {
237:       VecScatterBegin(stag->ltog_injective,l,g,mode,SCATTER_FORWARD);
238:     } else {
239:       VecScatterBegin(stag->gtol,l,g,mode,SCATTER_REVERSE_LOCAL);
240:     }
241:   } else SETERRQ(PetscObjectComm((PetscObject)dm),PETSC_ERR_SUP,"Unsupported InsertMode");
242:   return(0);
243: }

245: static PetscErrorCode DMLocalToGlobalEnd_Stag(DM dm,Vec l,InsertMode mode,Vec g)
246: {
247:   PetscErrorCode  ierr;
248:   DM_Stag * const stag = (DM_Stag*)dm->data;

251:   if (mode == ADD_VALUES) {
252:     VecScatterEnd(stag->gtol,l,g,mode,SCATTER_REVERSE);
253:   } else if (mode == INSERT_VALUES) {
254:     if (stag->ltog_injective) {
255:       VecScatterEnd(stag->ltog_injective,l,g,mode,SCATTER_FORWARD);
256:     } else {
257:       VecScatterEnd(stag->gtol,l,g,mode,SCATTER_REVERSE_LOCAL);
258:     }
259:   } else SETERRQ(PetscObjectComm((PetscObject)dm),PETSC_ERR_SUP,"Unsupported InsertMode");
260:   return(0);
261: }

263: static PetscErrorCode DMGlobalToLocalBegin_Stag(DM dm,Vec g,InsertMode mode,Vec l)
264: {
265:   PetscErrorCode  ierr;
266:   DM_Stag * const stag = (DM_Stag*)dm->data;

269:   VecScatterBegin(stag->gtol,g,l,mode,SCATTER_FORWARD);
270:   return(0);
271: }

273: static PetscErrorCode DMGlobalToLocalEnd_Stag(DM dm,Vec g,InsertMode mode,Vec l)
274: {
275:   PetscErrorCode  ierr;
276:   DM_Stag * const stag = (DM_Stag*)dm->data;

279:   VecScatterEnd(stag->gtol,g,l,mode,SCATTER_FORWARD);
280:   return(0);
281: }

283: /*
284: If a stratum is active (non-zero dof), make it active in the coordinate DM.
285: */
286: static PetscErrorCode DMCreateCoordinateDM_Stag(DM dm,DM *dmc)
287: {
288:   PetscErrorCode  ierr;
289:   DM_Stag * const stag = (DM_Stag*)dm->data;
290:   PetscInt        dim;
291:   PetscBool       isstag,isproduct;


295:   if (!stag->coordinateDMType) SETERRQ(PetscObjectComm((PetscObject)dm),PETSC_ERR_ARG_OUTOFRANGE,"Before creating a coordinate DM, a type must be specified with DMStagSetCoordinateDMType()");

297:   DMGetDimension(dm,&dim);
298:   PetscStrcmp(stag->coordinateDMType,DMSTAG,&isstag);
299:   PetscStrcmp(stag->coordinateDMType,DMPRODUCT,&isproduct);
300:   if (isstag) {
301:     DMStagCreateCompatibleDMStag(dm,
302:         stag->dof[0] > 0 ? dim : 0,
303:         stag->dof[1] > 0 ? dim : 0,
304:         stag->dof[2] > 0 ? dim : 0,
305:         stag->dof[3] > 0 ? dim : 0,
306:         dmc);
307:   } else if (isproduct) {
308:     DMCreate(PETSC_COMM_WORLD,dmc);
309:     DMSetType(*dmc,DMPRODUCT);
310:     DMSetDimension(*dmc,dim);
311:   } else SETERRQ1(PetscObjectComm((PetscObject)dm),PETSC_ERR_SUP,"Unsupported coordinate DM type %s",stag->coordinateDMType);
312:   return(0);
313: }

315: static PetscErrorCode DMGetNeighbors_Stag(DM dm,PetscInt *nRanks,const PetscMPIInt *ranks[])
316: {
317:   PetscErrorCode  ierr;
318:   DM_Stag * const stag = (DM_Stag*)dm->data;
319:   PetscInt        dim;

322:   DMGetDimension(dm,&dim);
323:   switch (dim) {
324:     case 1: *nRanks = 3; break;
325:     case 2: *nRanks = 9; break;
326:     case 3: *nRanks = 27; break;
327:     default : SETERRQ1(PetscObjectComm((PetscObject)dm),PETSC_ERR_SUP,"Get neighbors not implemented for dim = %D",dim);
328:   }
329:   *ranks = stag->neighbors;
330:   return(0);
331: }

333: static PetscErrorCode DMView_Stag(DM dm,PetscViewer viewer)
334: {
335:   PetscErrorCode  ierr;
336:   DM_Stag * const stag = (DM_Stag*)dm->data;
337:   PetscBool       isascii,viewAllRanks;
338:   PetscMPIInt     rank,size;
339:   PetscInt        dim,maxRanksToView,i;

342:   MPI_Comm_rank(PetscObjectComm((PetscObject)dm),&rank);
343:   MPI_Comm_size(PetscObjectComm((PetscObject)dm),&size);
344:   DMGetDimension(dm,&dim);
345:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERASCII,&isascii);
346:   if (isascii) {
347:     PetscViewerASCIIPrintf(viewer,"Dimension: %D\n",dim);
348:     switch (dim) {
349:       case 1:
350:         PetscViewerASCIIPrintf(viewer,"Global size: %D\n",stag->N[0]);
351:         break;
352:       case 2:
353:         PetscViewerASCIIPrintf(viewer,"Global sizes: %D x %D\n",stag->N[0],stag->N[1]);
354:         PetscViewerASCIIPrintf(viewer,"Parallel decomposition: %D x %D ranks\n",stag->nRanks[0],stag->nRanks[1]);
355:         break;
356:       case 3:
357:         PetscViewerASCIIPrintf(viewer,"Global sizes: %D x %D x %D\n",stag->N[0],stag->N[1],stag->N[2]);
358:         PetscViewerASCIIPrintf(viewer,"Parallel decomposition: %D x %D x %D ranks\n",stag->nRanks[0],stag->nRanks[1],stag->nRanks[2]);
359:         break;
360:       default: SETERRQ1(PetscObjectComm((PetscObject)dm),PETSC_ERR_SUP,"not implemented for dim==%D",dim);
361:     }
362:     PetscViewerASCIIPrintf(viewer,"Boundary ghosting:");
363:     for (i=0; i<dim; ++i) {
364:       PetscViewerASCIIPrintf(viewer," %s",DMBoundaryTypes[stag->boundaryType[i]]);
365:     }
366:     PetscViewerASCIIPrintf(viewer,"\n");
367:     PetscViewerASCIIPrintf(viewer,"Elementwise ghost stencil: %s, width %D\n",DMStagStencilTypes[stag->stencilType],stag->stencilWidth);
368:     PetscViewerASCIIPrintf(viewer,"Stratum dof:");
369:     for (i=0; i<dim+1; ++i) {
370:       PetscViewerASCIIPrintf(viewer," %D:%D",i,stag->dof[i]);
371:     }
372:     PetscViewerASCIIPrintf(viewer,"\n");
373:     if (dm->coordinateDM) {
374:       PetscViewerASCIIPrintf(viewer,"Has coordinate DM\n");
375:     }
376:     maxRanksToView = 16;
377:     viewAllRanks = (PetscBool)(size <= maxRanksToView);
378:     if (viewAllRanks) {
379:       PetscViewerASCIIPushSynchronized(viewer);
380:       switch (dim) {
381:         case 1:
382:           PetscViewerASCIISynchronizedPrintf(viewer,"[%d] Local elements : %D (%D with ghosts)\n",rank,stag->n[0],stag->nGhost[0]);
383:           break;
384:         case 2:
385:           PetscViewerASCIISynchronizedPrintf(viewer,"[%d] Rank coordinates (%d,%d)\n",rank,stag->rank[0],stag->rank[1]);
386:           PetscViewerASCIISynchronizedPrintf(viewer,"[%d] Local elements : %D x %D (%D x %D with ghosts)\n",rank,stag->n[0],stag->n[1],stag->nGhost[0],stag->nGhost[1]);
387:           break;
388:         case 3:
389:           PetscViewerASCIISynchronizedPrintf(viewer,"[%d] Rank coordinates (%d,%d,%d)\n",rank,stag->rank[0],stag->rank[1],stag->rank[2]);
390:           PetscViewerASCIISynchronizedPrintf(viewer,"[%d] Local elements : %D x %D x %D (%D x %D x %D with ghosts)\n",rank,stag->n[0],stag->n[1],stag->n[2],stag->nGhost[0],stag->nGhost[1],stag->nGhost[2]);
391:           break;
392:         default: SETERRQ1(PetscObjectComm((PetscObject)dm),PETSC_ERR_SUP,"not implemented for dim==%D",dim);
393:       }
394:       PetscViewerASCIISynchronizedPrintf(viewer,"[%d] Local native entries: %d\n",rank,stag->entries);
395:       PetscViewerASCIISynchronizedPrintf(viewer,"[%d] Local entries total : %d\n",rank,stag->entriesGhost);
396:       PetscViewerFlush(viewer);
397:       PetscViewerASCIIPopSynchronized(viewer);
398:     } else {
399:       PetscViewerASCIIPrintf(viewer,"(Per-rank information omitted since >%D ranks used)\n",maxRanksToView);
400:     }
401:   }
402:   return(0);
403: }

405: static PetscErrorCode DMSetFromOptions_Stag(PetscOptionItems *PetscOptionsObject,DM dm)
406: {
407:   PetscErrorCode  ierr;
408:   DM_Stag * const stag = (DM_Stag*)dm->data;
409:   PetscInt        dim;

412:   DMGetDimension(dm,&dim);
413:   PetscOptionsHead(PetscOptionsObject,"DMStag Options");
414:   PetscOptionsInt("-stag_grid_x","Number of grid points in x direction","DMStagSetGlobalSizes",stag->N[0],&stag->N[0],NULL);
415:   if (dim > 1) { PetscOptionsInt("-stag_grid_y","Number of grid points in y direction","DMStagSetGlobalSizes",stag->N[1],&stag->N[1],NULL); }
416:   if (dim > 2) { PetscOptionsInt("-stag_grid_z","Number of grid points in z direction","DMStagSetGlobalSizes",stag->N[2],&stag->N[2],NULL); }
417:   PetscOptionsInt("-stag_ranks_x","Number of ranks in x direction","DMStagSetNumRanks",stag->nRanks[0],&stag->nRanks[0],NULL);
418:   if (dim > 1) { PetscOptionsInt("-stag_ranks_y","Number of ranks in y direction","DMStagSetNumRanks",stag->nRanks[1],&stag->nRanks[1],NULL); }
419:   if (dim > 2) { PetscOptionsInt("-stag_ranks_z","Number of ranks in z direction","DMStagSetNumRanks",stag->nRanks[2],&stag->nRanks[2],NULL); }
420:   PetscOptionsInt("-stag_stencil_width","Elementwise stencil width","DMStagSetStencilWidth",stag->stencilWidth,&stag->stencilWidth,NULL);
421:   PetscOptionsEnum("-stag_stencil_type","Elementwise stencil stype","DMStagSetStencilType",DMStagStencilTypes,(PetscEnum)stag->stencilType,(PetscEnum*)&stag->stencilType,NULL);
422:   PetscOptionsEnum("-stag_boundary_type_x","Treatment of (physical) boundaries in x direction","DMStagSetBoundaryTypes",DMBoundaryTypes,(PetscEnum)stag->boundaryType[0],(PetscEnum*)&stag->boundaryType[0],NULL);
423:   PetscOptionsEnum("-stag_boundary_type_y","Treatment of (physical) boundaries in y direction","DMStagSetBoundaryTypes",DMBoundaryTypes,(PetscEnum)stag->boundaryType[1],(PetscEnum*)&stag->boundaryType[1],NULL);
424:   PetscOptionsEnum("-stag_boundary_type_z","Treatment of (physical) boundaries in z direction","DMStagSetBoundaryTypes",DMBoundaryTypes,(PetscEnum)stag->boundaryType[2],(PetscEnum*)&stag->boundaryType[2],NULL);
425:   PetscOptionsInt("-stag_dof_0","Number of dof per 0-cell (vertex/corner)","DMStagSetDOF",stag->dof[0],&stag->dof[0],NULL);
426:   PetscOptionsInt("-stag_dof_1","Number of dof per 1-cell (edge)",         "DMStagSetDOF",stag->dof[1],&stag->dof[1],NULL);
427:   PetscOptionsInt("-stag_dof_2","Number of dof per 2-cell (face)",         "DMStagSetDOF",stag->dof[2],&stag->dof[2],NULL);
428:   PetscOptionsInt("-stag_dof_3","Number of dof per 3-cell (hexahedron)",   "DMStagSetDOF",stag->dof[3],&stag->dof[3],NULL);
429:   PetscOptionsTail();
430:   return(0);
431: }

433: /*MC
434:   DMSTAG = "stag" - A DM object representing a "staggered grid" or a structured cell complex.

436:   This implementation parallels the DMDA implementation in many ways, but allows degrees of freedom
437:   to be associated with all "strata" in a logically-rectangular grid: vertices, edges, faces, and elements.

439:   Level: beginner

441: .seealso: DM, DMPRODUCT, DMDA, DMPLEX, DMStagCreate1d(), DMStagCreate2d(), DMStagCreate3d(), DMType, DMCreate(), DMSetType()
442: M*/

444: PETSC_EXTERN PetscErrorCode DMCreate_Stag(DM dm)
445: {
447:   DM_Stag        *stag;
448:   PetscInt       i,dim;

452:   PetscNewLog(dm,&stag);
453:   dm->data = stag;

455:   stag->gtol                                          = NULL;
456:   stag->ltog_injective                                = NULL;
457:   for (i=0; i<DMSTAG_MAX_STRATA; ++i) stag->dof[i]    = 0;
458:   for (i=0; i<DMSTAG_MAX_DIM;    ++i) stag->l[i]      = NULL;
459:   stag->stencilType                                   = DMSTAG_STENCIL_NONE;
460:   stag->stencilWidth                                  = 0;
461:   for (i=0; i<DMSTAG_MAX_DIM;    ++i) stag->nRanks[i] = -1;
462:   stag->coordinateDMType                              = NULL;

464:   DMGetDimension(dm,&dim);
465:   if (dim != 1 && dim != 2 && dim != 3) SETERRQ(PetscObjectComm((PetscObject)dm),PETSC_ERR_ARG_WRONGSTATE,"DMSetDimension() must be called to set a dimension with value 1, 2, or 3");

467:   PetscMemzero(dm->ops,sizeof(*(dm->ops)));
468:   dm->ops->createcoordinatedm  = DMCreateCoordinateDM_Stag;
469:   dm->ops->createglobalvector  = DMCreateGlobalVector_Stag;
470:   dm->ops->createinterpolation = NULL;
471:   dm->ops->createlocalvector   = DMCreateLocalVector_Stag;
472:   dm->ops->creatematrix        = DMCreateMatrix_Stag;
473:   dm->ops->destroy             = DMDestroy_Stag;
474:   dm->ops->getneighbors        = DMGetNeighbors_Stag;
475:   dm->ops->globaltolocalbegin  = DMGlobalToLocalBegin_Stag;
476:   dm->ops->globaltolocalend    = DMGlobalToLocalEnd_Stag;
477:   dm->ops->localtoglobalbegin  = DMLocalToGlobalBegin_Stag;
478:   dm->ops->localtoglobalend    = DMLocalToGlobalEnd_Stag;
479:   dm->ops->setfromoptions      = DMSetFromOptions_Stag;
480:   switch (dim) {
481:     case 1: dm->ops->setup     = DMSetUp_Stag_1d; break;
482:     case 2: dm->ops->setup     = DMSetUp_Stag_2d; break;
483:     case 3: dm->ops->setup     = DMSetUp_Stag_3d; break;
484:     default : SETERRQ1(PetscObjectComm((PetscObject)dm),PETSC_ERR_ARG_OUTOFRANGE,"Unsupported dimension %d",dim);
485:   }
486:   dm->ops->clone               = DMClone_Stag;
487:   dm->ops->view                = DMView_Stag;
488:   dm->ops->getcompatibility    = DMGetCompatibility_Stag;
489:   return(0);
490: }