xref: /petsc/src/dm/impls/moab/dmmbutil.cxx (revision 609bdbee21ea3be08735c64dbe00a9ab27759925)
1 #include <petsc/private/dmmbimpl.h> /*I  "petscdmmoab.h"   I*/
2 #include <petsc/private/vecimpl.h>
3 
4 #include <petscdmmoab.h>
5 #include <MBTagConventions.hpp>
6 #include <moab/ReadUtilIface.hpp>
7 #include <moab/ScdInterface.hpp>
8 #include <moab/CN.hpp>
9 
10 
11 static PetscErrorCode DMMoabComputeDomainBounds_Private(moab::ParallelComm* pcomm, PetscInt dim, PetscInt neleglob, PetscInt *ise)
12 {
13   PetscInt size,rank;
14   PetscInt fraction,remainder;
15   PetscInt starts[3],sizes[3];
16 
17   PetscFunctionBegin;
18   if(dim<1 && dim>3) SETERRQ1(PETSC_COMM_WORLD,PETSC_ERR_ARG_OUTOFRANGE,"The problem dimension is invalid: %D",dim);
19 
20   size=pcomm->size();
21   rank=pcomm->rank();
22   fraction=neleglob/size;    /* partition only by the largest dimension */
23   remainder=neleglob%size;   /* remainder after partition which gets evenly distributed by round-robin */
24 
25   if(fraction==0) SETERRQ2(PETSC_COMM_WORLD,PETSC_ERR_ARG_OUTOFRANGE,"The leading dimension size should be greater than number of processors: %D < %D",neleglob,size);
26 
27   starts[0]=starts[1]=starts[2]=0;       /* default dimensional element = 1 */
28   sizes[0]=sizes[1]=sizes[2]=neleglob;   /* default dimensional element = 1 */
29 
30   if(rank < remainder) { /* This process gets "fraction+1" elements */
31     sizes[dim-1] = (fraction + 1);
32     starts[dim-1] = rank * (fraction+1);
33   } else { /* This process gets "fraction" elements */
34     sizes[dim-1] = fraction;
35     starts[dim-1] = (remainder*(fraction+1) + fraction*(rank-remainder));
36   }
37 
38   for(int i=dim-1; i>=0; --i) {
39     ise[2*i]=starts[i];ise[2*i+1]=starts[i]+sizes[i];
40   }
41   PetscFunctionReturn(0);
42 }
43 
44 static void DMMoab_SetStructuredCoords_Private(PetscInt i, PetscInt j, PetscInt k, PetscReal hx, PetscReal hy, PetscReal hz, PetscInt vcount, std::vector<double*>& vcoords)
45 {
46   vcoords[0][vcount] = i*hx;
47   vcoords[1][vcount] = j*hy;
48   vcoords[2][vcount] = k*hz;
49 }
50 
51 static void DMMoab_SetTensorElementConnectivity_Private(PetscInt dim, moab::EntityType etype, PetscInt offset, PetscInt nele, PetscInt i, PetscInt j, PetscInt k, PetscInt vfirst, moab::EntityHandle *connectivity)
52 {
53   std::vector<int>    subent_conn(pow(2,dim));  /* only linear edge, quad, hex supported now */
54 
55   moab::CN::SubEntityVertexIndices(etype, dim, 0, subent_conn.data());
56 
57   switch(dim) {
58     case 1:
59       connectivity[offset+subent_conn[0]] = vfirst+i;
60       connectivity[offset+subent_conn[1]] = vfirst+(i+1);
61       break;
62     case 2:
63       connectivity[offset+subent_conn[0]] = vfirst+i+j*(nele+1);
64       connectivity[offset+subent_conn[1]] = vfirst+(i+1)+j*(nele+1);
65       connectivity[offset+subent_conn[2]] = vfirst+(i+1)+(j+1)*(nele+1);
66       connectivity[offset+subent_conn[3]] = vfirst+i+(j+1)*(nele+1);
67       break;
68     case 3:
69     default:
70       connectivity[offset+subent_conn[0]] = vfirst+i+(nele+1)*(j+(nele+1)*k);
71       connectivity[offset+subent_conn[1]] = vfirst+(i+1)+(nele+1)*(j+(nele+1)*k);
72       connectivity[offset+subent_conn[2]] = vfirst+(i+1)+(nele+1)*((j+1)+(nele+1)*k);
73       connectivity[offset+subent_conn[3]] = vfirst+i+(nele+1)*((j+1)+(nele+1)*k);
74       connectivity[offset+subent_conn[4]] = vfirst+i+(nele+1)*(j+(nele+1)*(k+1));
75       connectivity[offset+subent_conn[5]] = vfirst+(i+1)+(nele+1)*(j+(nele+1)*(k+1));
76       connectivity[offset+subent_conn[6]] = vfirst+(i+1)+(nele+1)*((j+1)+(nele+1)*(k+1));
77       connectivity[offset+subent_conn[7]] = vfirst+i+(nele+1)*((j+1)+(nele+1)*(k+1));
78       break;
79   }
80 }
81 
82 static void DMMoab_SetSimplexElementConnectivity_Private(PetscInt dim, PetscInt subelem, moab::EntityType etype, PetscInt offset, PetscInt nele, PetscInt i, PetscInt j, PetscInt k, PetscInt vfirst, moab::EntityHandle *connectivity)
83 {
84   std::vector<int>    subent_conn(pow(2,dim));  /* only linear edge, quad, hex supported now */
85 
86   moab::CN::SubEntityVertexIndices(etype, dim, 0, subent_conn.data());
87 
88   switch(dim) {
89     case 1:
90       connectivity[offset+subent_conn[0]] = vfirst+i;
91       connectivity[offset+subent_conn[1]] = vfirst+(i+1);
92       break;
93     case 2:
94       if (subelem) { /* 1 2 3 of a QUAD */
95         connectivity[offset+subent_conn[0]] = vfirst+i+j*(nele+1);
96         connectivity[offset+subent_conn[1]] = vfirst+(i+1)+j*(nele+1);
97         connectivity[offset+subent_conn[2]] = vfirst+(i+1)+(j+1)*(nele+1);
98       }
99       else {        /* 3 4 1 of a QUAD */
100         connectivity[offset+subent_conn[0]] = vfirst+(i+1)+(j+1)*(nele+1);
101         connectivity[offset+subent_conn[1]] = vfirst+i+(j+1)*(nele+1);
102         connectivity[offset+subent_conn[2]] = vfirst+i+j*(nele+1);
103       }
104       break;
105     case 3:
106     default:
107       switch(subelem) {
108         case 0: /* 0 1 2 5 of a HEX */
109           connectivity[offset+subent_conn[0]] = vfirst+i+(nele+1)*(j+(nele+1)*k);
110           connectivity[offset+subent_conn[1]] = vfirst+(i+1)+(nele+1)*(j+(nele+1)*k);
111           connectivity[offset+subent_conn[2]] = vfirst+(i+1)+(nele+1)*((j+1)+(nele+1)*k);
112           connectivity[offset+subent_conn[3]] = vfirst+(i+1)+(nele+1)*(j+(nele+1)*(k+1));
113           break;
114         case 1: /* 0 2 7 5 of a HEX */
115           connectivity[offset+subent_conn[0]] = vfirst+i+(nele+1)*(j+(nele+1)*k);
116           connectivity[offset+subent_conn[1]] = vfirst+(i+1)+(nele+1)*((j+1)+(nele+1)*k);
117           connectivity[offset+subent_conn[2]] = vfirst+i+(nele+1)*((j+1)+(nele+1)*(k+1));
118           connectivity[offset+subent_conn[3]] = vfirst+(i+1)+(nele+1)*(j+(nele+1)*(k+1));
119           break;
120         case 2: /* 0 2 3 7 of a HEX */
121           connectivity[offset+subent_conn[0]] = vfirst+i+(nele+1)*(j+(nele+1)*k);
122           connectivity[offset+subent_conn[1]] = vfirst+(i+1)+(nele+1)*((j+1)+(nele+1)*k);
123           connectivity[offset+subent_conn[2]] = vfirst+i+(nele+1)*((j+1)+(nele+1)*k);
124           connectivity[offset+subent_conn[3]] = vfirst+i+(nele+1)*((j+1)+(nele+1)*(k+1));
125           break;
126         case 3: /* 0 5 7 4 of a HEX */
127           connectivity[offset+subent_conn[0]] = vfirst+i+(nele+1)*(j+(nele+1)*k);
128           connectivity[offset+subent_conn[1]] = vfirst+(i+1)+(nele+1)*(j+(nele+1)*(k+1));
129           connectivity[offset+subent_conn[2]] = vfirst+i+(nele+1)*((j+1)+(nele+1)*(k+1));
130           connectivity[offset+subent_conn[3]] = vfirst+i+(nele+1)*(j+(nele+1)*(k+1));
131           break;
132         case 4: /* 2 7 5 6 of a HEX */
133           connectivity[offset+subent_conn[0]] = vfirst+(i+1)+(nele+1)*((j+1)+(nele+1)*k);
134           connectivity[offset+subent_conn[1]] = vfirst+i+(nele+1)*((j+1)+(nele+1)*(k+1));
135           connectivity[offset+subent_conn[2]] = vfirst+(i+1)+(nele+1)*(j+(nele+1)*(k+1));
136           connectivity[offset+subent_conn[3]] = vfirst+(i+1)+(nele+1)*((j+1)+(nele+1)*(k+1));
137           break;
138       }
139       break;
140   }
141 }
142 
143 static void DMMoab_SetElementConnectivity_Private(PetscBool useSimplex, PetscInt dim, moab::EntityType etype, PetscInt *ecount, PetscInt vpere, PetscInt nele, PetscInt i, PetscInt j, PetscInt k, PetscInt vfirst, moab::EntityHandle *connectivity)
144 {
145   PetscInt m,subelem;
146   if (useSimplex) {
147     subelem=(dim==1 ? 1 : (dim==2 ? 2 : 5));
148     for (m=0; m<subelem; m++)
149       DMMoab_SetSimplexElementConnectivity_Private(dim, m, etype, (*ecount+m)*vpere, nele, i, j, k, vfirst, connectivity);
150 
151   }
152   else {
153     subelem=1;
154     DMMoab_SetTensorElementConnectivity_Private(dim, etype, (*ecount)*vpere, nele, i, j, k, vfirst, connectivity);
155   }
156   *ecount+=subelem;
157 }
158 
159 
160 /*@
161   DMMoabCreateBoxMesh - Creates a mesh on the tensor product (box) of intervals with user specified bounds.
162 
163   Collective on MPI_Comm
164 
165   Input Parameters:
166 + comm - The communicator for the DM object
167 . dim - The spatial dimension
168 . bounds - The bounds of the box specified with [x-left, x-right, y-bottom, y-top, z-bottom, z-top] depending on the spatial dimension
169 . nele - The number of discrete elements in each direction
170 . user_nghost - The number of ghosted layers needed in the partitioned mesh
171 
172   Output Parameter:
173 . dm  - The DM object
174 
175   Level: beginner
176 
177 .keywords: DM, create
178 .seealso: DMSetType(), DMCreate(), DMMoabLoadFromFile()
179 @*/
180 PetscErrorCode DMMoabCreateBoxMesh(MPI_Comm comm, PetscInt dim, PetscBool useSimplex, const PetscReal* bounds, PetscInt nele, PetscInt user_nghost, DM *dm)
181 {
182   PetscErrorCode  ierr;
183   moab::ErrorCode merr;
184   PetscInt        i,j,k,n,nprocs;
185   DM_Moab        *dmmoab;
186   moab::Interface *mbiface;
187   moab::ParallelComm *pcomm;
188   moab::ReadUtilIface* readMeshIface;
189 
190   moab::Tag  id_tag=NULL;
191   moab::Range         ownedvtx,ownedelms;
192   moab::EntityHandle  vfirst,efirst,regionset,faceset,edgeset,vtxset;
193   std::vector<double*> vcoords;
194   moab::EntityHandle  *connectivity = 0;
195   moab::EntityType etype=moab::MBHEX;
196   PetscInt    ise[6];
197   PetscReal   xse[6],defbounds[6];
198   /* TODO: Fix nghost > 0 - now relying on exchange_ghost_cells */
199   const PetscInt nghost=0;
200 
201   moab::Tag geom_tag;
202 
203   moab::Range adj,dim3,dim2;
204   bool build_adjacencies=false;
205 
206   const PetscInt npts=nele+1;        /* Number of points in every dimension */
207   PetscInt vpere=0,locnele=0,locnpts=0,ghnele,ghnpts;    /* Number of verts/element, vertices, elements owned by this process */
208 
209   PetscFunctionBegin;
210   if(dim < 1 || dim > 3) SETERRQ(PETSC_COMM_WORLD,PETSC_ERR_ARG_OUTOFRANGE,"Invalid dimension argument for mesh: dim=[1,3].\n");
211 
212   ierr = MPI_Comm_size(comm, &nprocs);CHKERRQ(ierr);
213   /* total number of vertices in all dimensions */
214   n=pow(npts,dim);
215 
216   /* do some error checking */
217   if(n < 2) SETERRQ(PETSC_COMM_WORLD,PETSC_ERR_ARG_OUTOFRANGE,"Number of points must be >= 2.\n");
218   if(nprocs > n) SETERRQ(PETSC_COMM_WORLD,PETSC_ERR_ARG_OUTOFRANGE,"Number of processors must be less than or equal to number of elements.\n");
219   if(nghost < 0) SETERRQ(PETSC_COMM_WORLD,PETSC_ERR_ARG_OUTOFRANGE,"Number of ghost layers cannot be negative.\n");
220 
221   /* Create the basic DMMoab object and keep the default parameters created by DM impls */
222   ierr = DMMoabCreateMoab(comm, NULL, NULL, NULL, NULL, dm);CHKERRQ(ierr);
223 
224   /* get all the necessary handles from the private DM object */
225   dmmoab = (DM_Moab*)(*dm)->data;
226   mbiface = dmmoab->mbiface;
227   pcomm = dmmoab->pcomm;
228   id_tag = dmmoab->ltog_tag;
229   nprocs = pcomm->size();
230   dmmoab->dim = dim;
231 
232   /* create a file set to associate all entities in current mesh */
233   merr = dmmoab->mbiface->create_meshset(moab::MESHSET_SET, dmmoab->fileset);MBERR("Creating file set failed", merr);
234 
235   /* No errors yet; proceed with building the mesh */
236   merr = mbiface->query_interface(readMeshIface);MBERRNM(merr);
237 
238   ierr = PetscMemzero(ise,sizeof(PetscInt)*6);CHKERRQ(ierr);
239 
240   /* call the collective routine that computes the domain bounds for a structured mesh using MOAB */
241   ierr = DMMoabComputeDomainBounds_Private(pcomm, dim, nele, ise);CHKERRQ(ierr);
242 
243   /* set some variables based on dimension */
244   switch(dim) {
245    case 1:
246     vpere = 2;
247     locnele = (ise[1]-ise[0]);
248     locnpts = (ise[1]-ise[0]+1);
249     ghnele = (nghost > 0 ? (ise[0] > nghost ? 1 : 0) + (ise[1] < nele - nghost ? 1 : 0) : 0 );
250     ghnpts = (nghost > 0 ? (ise[0] > 0 ? 1 : 0) + (ise[1] < nele ? 1 : 0) : 0);
251     etype = moab::MBEDGE;
252     break;
253    case 2:
254     locnpts = (ise[1]-ise[0]+1)*(ise[3]-ise[2]+1);
255     ghnpts = (nghost > 0 ? (ise[2] > 0 ? npts : 0) + (ise[3] < nele ? npts : 0) : 0);
256     if (useSimplex) {
257       vpere = 3;
258       locnele = 2*(ise[1]-ise[0])*(ise[3]-ise[2]);
259       ghnele = 2*(nghost > 0 ? (ise[2] > 0 ? nele : 0) + (ise[3] < nele ? nele : 0) : 0);
260       etype = moab::MBTRI;
261     }
262     else {
263       vpere = 4;
264       locnele = (ise[1]-ise[0])*(ise[3]-ise[2]);
265       ghnele = (nghost > 0 ? (ise[2] > 0 ? nele : 0) + (ise[3] < nele ? nele : 0) : 0);
266       etype = moab::MBQUAD;
267     }
268     break;
269    case 3:
270    default:
271     locnpts = (ise[1]-ise[0]+1)*(ise[3]-ise[2]+1)*(ise[5]-ise[4]+1);
272     ghnpts = (nghost > 0 ? (ise[4] > 0 ? npts*npts : 0) + (ise[5] < nele ? npts*npts : 0) : 0);
273     if (useSimplex) {
274       vpere = 4;
275       locnele = 5*(ise[1]-ise[0])*(ise[3]-ise[2])*(ise[5]-ise[4]);
276       ghnele = 5*(nghost > 0 ? (ise[4] > 0 ? nele*nele : 0) + (ise[5] < nele ? nele*nele : 0) : 0);
277       etype = moab::MBTET;
278     }
279     else {
280       vpere = 8;
281       locnele = (ise[1]-ise[0])*(ise[3]-ise[2])*(ise[5]-ise[4]);
282       ghnele = (nghost > 0 ? (ise[4] > 0 ? nele*nele : 0) + (ise[5] < nele ? nele*nele : 0) : 0);
283       etype = moab::MBHEX;
284     }
285     break;
286   }
287 
288   /* we have a domain of size [1,1,1] - now compute local co-ordinate box */
289   ierr = PetscMemzero(xse,sizeof(PetscReal)*6);CHKERRQ(ierr);
290   for(i=0; i<6; ++i) {
291     xse[i]=(PetscReal)ise[i]/nele;
292   }
293 
294   /* Create vertexes and set the coodinate of each vertex */
295   merr = readMeshIface->get_node_coords(3,locnpts+ghnpts,0,vfirst,vcoords,n);MBERRNM(merr);
296 
297   /* Compute the co-ordinates of vertices and global IDs */
298   std::vector<int>    vgid(locnpts+ghnpts);
299   int vcount=0;
300 
301   if (!bounds) { /* default box mesh is defined on a unit-cube */
302     defbounds[0]=0.0; defbounds[1]=1.0;
303     defbounds[2]=0.0; defbounds[3]=1.0;
304     defbounds[4]=0.0; defbounds[5]=1.0;
305     bounds=defbounds;
306   }
307   else {
308     /* validate the bounds data */
309     if(bounds[0] >= bounds[1]) SETERRQ2(PETSC_COMM_WORLD,PETSC_ERR_ARG_OUTOFRANGE,"X-dim: Left boundary cannot be greater than right. [%G >= %G]\n",bounds[0],bounds[1]);
310     if(dim > 1 && (bounds[2] >= bounds[3])) SETERRQ2(PETSC_COMM_WORLD,PETSC_ERR_ARG_OUTOFRANGE,"Y-dim: Left boundary cannot be greater than right. [%G >= %G]\n",bounds[2],bounds[3]);
311     if(dim > 2 && (bounds[4] >= bounds[5])) SETERRQ2(PETSC_COMM_WORLD,PETSC_ERR_ARG_OUTOFRANGE,"Z-dim: Left boundary cannot be greater than right. [%G >= %G]\n",bounds[4],bounds[5]);
312   }
313 
314   const double hx=(bounds[1]-bounds[0])/nele;
315   const double hy=(dim > 1 ? (bounds[3]-bounds[2])/nele : 0.0);
316   const double hz=(dim > 2 ? (bounds[5]-bounds[4])/nele : 0.0);
317 
318   /* create all the owned vertices */
319   for (k = ise[4]; k <= ise[5]; k++) {
320     for (j = ise[2]; j <= ise[3]; j++) {
321       for (i = ise[0]; i <= ise[1]; i++, vcount++) {
322         DMMoab_SetStructuredCoords_Private(i,j,k,hx,hy,hz,vcount,vcoords);
323         vgid[vcount] = (k*npts+j)*npts+i+1;
324       }
325     }
326   }
327 
328   /* create ghosted vertices requested by user - below the current plane */
329   if (ise[2*dim-2] > 0) {
330     for (k = (dim==3?ise[4]-nghost:ise[4]); k <= (dim==3?ise[4]-1:ise[5]); k++) {
331       for (j = (dim==2?ise[2]-nghost:ise[2]); j <= (dim==2?ise[2]-1:ise[3]); j++) {
332         for (i = (dim>1?ise[0]:ise[0]-nghost); i <= (dim>1?ise[1]:ise[0]-1); i++, vcount++) {
333           DMMoab_SetStructuredCoords_Private(i,j,k,hx,hy,hz,vcount,vcoords);
334           vgid[vcount] = (k*npts+j)*npts+i+1;
335         }
336       }
337     }
338   }
339 
340   /* create ghosted vertices requested by user - above the current plane */
341   if (ise[2*dim-1] < nele) {
342     for (k = (dim==3?ise[5]+1:ise[4]); k <= (dim==3?ise[5]+nghost:ise[5]); k++) {
343       for (j = (dim==2?ise[3]+1:ise[2]); j <= (dim==2?ise[3]+nghost:ise[3]); j++) {
344         for (i = (dim>1?ise[0]:ise[1]+1); i <= (dim>1?ise[1]:ise[1]+nghost); i++, vcount++) {
345           DMMoab_SetStructuredCoords_Private(i,j,k,hx,hy,hz,vcount,vcoords);
346           vgid[vcount] = (k*npts+j)*npts+i+1;
347         }
348       }
349     }
350   }
351 
352   if (locnpts+ghnpts != vcount) SETERRQ2(PETSC_COMM_WORLD,PETSC_ERR_ARG_OUTOFRANGE,"Created the wrong number of vertices! (%D!=%D)",locnpts+ghnpts,vcount);
353 
354   merr = mbiface->get_entities_by_type(0,moab::MBVERTEX,ownedvtx,true);MBERRNM(merr);
355 
356   /* The global ID tag is applied to each owned
357      vertex. It acts as an global identifier which MOAB uses to
358      assemble the individual pieces of the mesh:
359      Set the global ID indices */
360   merr = mbiface->tag_set_data(id_tag,ownedvtx,vgid.data());MBERRNM(merr);
361 
362   /* Create elements between mesh points using the ReadUtilInterface
363      get the reference to element connectivities for all local elements from the ReadUtilInterface */
364   merr = readMeshIface->get_element_connect (locnele+ghnele,vpere,etype,1,efirst,connectivity);MBERRNM(merr);
365 
366   /* offset appropriately so that only local ID and not global ID numbers are set for connectivity array */
367   vfirst-=vgid[0]-1;
368 
369    /* 3. Loop over elements in 3 nested loops over i, j, k; for each (i,j,k):
370          and then set the connectivity for each element appropriately */
371   int ecount=0;
372 
373   /* create ghosted elements requested by user - below the current plane */
374   if (ise[2*dim-2] >= nghost) {
375     for (k = (dim==3?ise[4]-nghost:ise[4]); k < (dim==3?ise[4]:std::max(ise[5],1)); k++) {
376       for (j = (dim==2?ise[2]-nghost:ise[2]); j < (dim==2?ise[2]:std::max(ise[3],1)); j++) {
377         for (i = (dim>1?ise[0]:ise[0]-nghost); i < (dim>1?std::max(ise[1],1):ise[0]); i++) {
378           DMMoab_SetElementConnectivity_Private(useSimplex, dim, etype, &ecount, vpere, nele, i, j, k, vfirst, connectivity);
379         }
380       }
381     }
382   }
383 
384   /* create owned elements requested by user */
385   for (k = ise[4]; k < std::max(ise[5],1); k++) {
386     for (j = ise[2]; j < std::max(ise[3],1); j++) {
387       for (i = ise[0]; i < std::max(ise[1],1); i++) {
388         DMMoab_SetElementConnectivity_Private(useSimplex, dim, etype, &ecount, vpere, nele, i, j, k, vfirst, connectivity);
389       }
390     }
391   }
392 
393   /* create ghosted elements requested by user - above the current plane */
394   if (ise[2*dim-1] <= nele-nghost) {
395     for (k = (dim==3?ise[5]:ise[4]); k < (dim==3?ise[5]+nghost:std::max(ise[5],1)); k++) {
396       for (j = (dim==2?ise[3]:ise[2]); j < (dim==2?ise[3]+nghost:std::max(ise[3],1)); j++) {
397         for (i = (dim>1?ise[0]:ise[1]); i < (dim>1?std::max(ise[1],1):ise[1]+nghost); i++) {
398           DMMoab_SetElementConnectivity_Private(useSimplex, dim, etype, &ecount, vpere, nele, i, j, k, vfirst, connectivity);
399         }
400       }
401     }
402   }
403 
404   merr = readMeshIface->update_adjacencies(efirst,locnele+ghnele,vpere,connectivity);MBERRNM(merr);
405 
406   /* 2. Get the vertices and hexes from moab and check their numbers against I*J*K and (I-1)*(J-1)*(K-1), resp.
407         first '0' specifies "root set", or entire MOAB instance, second the entity dimension being requested */
408   merr = mbiface->get_entities_by_dimension(0, dim, ownedelms);MBERRNM(merr);
409 
410   if (locnele+ghnele != (int) ownedelms.size()) SETERRQ2(PETSC_COMM_WORLD,PETSC_ERR_ARG_OUTOFRANGE,"Created the wrong number of elements! (%D!=%D)",locnele+ghnele,ownedelms.size());
411   else if(locnpts+ghnpts != (int) ownedvtx.size()) SETERRQ2(PETSC_COMM_WORLD,PETSC_ERR_ARG_OUTOFRANGE,"Created the wrong number of vertices! (%D!=%D)",locnpts+ghnpts,ownedvtx.size());
412   else {
413     ierr = PetscInfo2(NULL, "Created %D elements and %D vertices.\n", ownedelms.size(), ownedvtx.size());CHKERRQ(ierr);
414   }
415 
416   /* lets create some sets */
417   merr = mbiface->tag_get_handle(GEOM_DIMENSION_TAG_NAME, 1, moab::MB_TYPE_INTEGER, geom_tag, moab::MB_TAG_SPARSE|moab::MB_TAG_CREAT);MBERRNM(merr);
418 
419   merr = mbiface->create_meshset(moab::MESHSET_SET, regionset);MBERRNM(merr);
420   merr = mbiface->add_entities(regionset, ownedelms);MBERRNM(merr);
421   merr = mbiface->tag_set_data(geom_tag, &regionset, 1, &dmmoab->dim);MBERRNM(merr);
422   merr = mbiface->add_parent_child(dmmoab->fileset,regionset);MBERRNM(merr);
423   merr = mbiface->unite_meshset(dmmoab->fileset, regionset);MBERRNM(merr);
424 
425   merr = mbiface->create_meshset(moab::MESHSET_SET, vtxset);MBERRNM(merr);
426   merr = mbiface->add_entities(vtxset, ownedvtx);MBERRNM(merr);
427   merr = mbiface->add_parent_child(dmmoab->fileset,vtxset);MBERRNM(merr);
428   merr = mbiface->unite_meshset(dmmoab->fileset, vtxset);MBERRNM(merr);
429 
430   if (build_adjacencies) {
431     // generate all lower dimensional adjacencies
432     merr = mbiface->get_adjacencies( ownedelms, dim-1, true, adj, moab::Interface::UNION );MBERRNM(merr);
433     merr = dmmoab->pcomm->get_part_entities(dim2, dim-1);MBERRNM(merr);
434     adj.merge(dim2);
435 
436     /* create face sets */
437     merr = mbiface->create_meshset(moab::MESHSET_SET, faceset);MBERRNM(merr);
438     merr = mbiface->add_entities(faceset, adj);MBERRNM(merr);
439     merr = mbiface->add_parent_child(dmmoab->fileset,faceset);MBERRNM(merr);
440     i=dim-1;
441     merr = mbiface->tag_set_data(geom_tag, &faceset, 1, &i);MBERRNM(merr);
442     merr = mbiface->unite_meshset(dmmoab->fileset, faceset);MBERRNM(merr);
443     PetscInfo2(NULL, "Found %d %d-Dim quantities.\n", adj.size(), dim-1);
444 
445     if (dim > 2) {
446       dim2.clear();
447       /* create edge sets, if appropriate i.e., if dim=3 */
448       merr = mbiface->create_meshset(moab::MESHSET_SET, edgeset);MBERRNM(merr);
449       merr = mbiface->get_adjacencies(adj, dim-1, true, dim2, moab::Interface::UNION );MBERRNM(merr);
450       merr = mbiface->add_entities(edgeset, dim2);MBERRNM(merr);
451       merr = mbiface->add_parent_child(dmmoab->fileset,edgeset);MBERRNM(merr);
452       i=dim-2;
453       merr = mbiface->tag_set_data(geom_tag, &edgeset, 1, &i);MBERRNM(merr);
454       merr = mbiface->unite_meshset(dmmoab->fileset, edgeset);MBERRNM(merr);
455       PetscInfo2(NULL, "Found %d %d-Dim quantities.\n", adj.size(), dim-2);
456     }
457   }
458 
459   /* check the handles */
460   merr = pcomm->check_all_shared_handles();MBERRV(mbiface,merr);
461 
462   /* resolve the shared entities by exchanging information to adjacent processors */
463   merr = mbiface->get_entities_by_type(dmmoab->fileset,etype,ownedelms,true);MBERRNM(merr);
464   merr = pcomm->resolve_shared_ents(dmmoab->fileset,ownedelms,dim,dim-1,NULL,&id_tag);MBERRV(mbiface,merr);
465 
466   merr = pcomm->exchange_ghost_cells(dim,0,user_nghost,dim,true,false,&dmmoab->fileset);MBERRV(mbiface,merr);
467 
468   /* Reassign global IDs on all entities. */
469   merr = pcomm->assign_global_ids(dmmoab->fileset,dim,1,false,true,false);MBERRNM(merr);
470 
471   /* Everything is set up, now just do a tag exchange to update tags
472      on all of the ghost vertexes */
473   merr = mbiface->get_entities_by_type(dmmoab->fileset,moab::MBVERTEX,ownedvtx,true);MBERRNM(merr);
474   merr = mbiface->get_entities_by_dimension(dmmoab->fileset, dim, ownedelms);MBERRNM(merr);
475 
476   merr = pcomm->exchange_tags(id_tag,ownedvtx);MBERRV(mbiface,merr);
477   merr = pcomm->exchange_tags(id_tag,ownedelms);MBERRV(mbiface,merr);
478   PetscFunctionReturn(0);
479 }
480 
481 
482 PetscErrorCode DMMoab_GetReadOptions_Private(PetscBool by_rank, PetscInt numproc, PetscInt dim, MoabReadMode mode, PetscInt dbglevel, const char* dm_opts, const char* extra_opts, const char** read_opts)
483 {
484   char           *ropts;
485   char           ropts_par[PETSC_MAX_PATH_LEN];
486   char           ropts_dbg[PETSC_MAX_PATH_LEN];
487   PetscErrorCode ierr;
488 
489   PetscFunctionBegin;
490   ierr = PetscMalloc1(PETSC_MAX_PATH_LEN,&ropts);CHKERRQ(ierr);
491   ierr = PetscMemzero(&ropts_par,PETSC_MAX_PATH_LEN);CHKERRQ(ierr);
492   ierr = PetscMemzero(&ropts_dbg,PETSC_MAX_PATH_LEN);CHKERRQ(ierr);
493 
494   /* do parallel read unless using only one processor */
495   if (numproc > 1) {
496     ierr = PetscSNPrintf(ropts_par, PETSC_MAX_PATH_LEN, "PARALLEL=%s;PARTITION=PARALLEL_PARTITION;PARTITION_DISTRIBUTE;PARALLEL_RESOLVE_SHARED_ENTS;PARALLEL_GHOSTS=%d.0.1%s;",MoabReadModes[mode],dim,(by_rank ? ";PARTITION_BY_RANK":""));CHKERRQ(ierr);
497   }
498 
499   if (dbglevel) {
500     if (numproc>1) {
501       ierr = PetscSNPrintf(ropts_dbg, PETSC_MAX_PATH_LEN, "%sCPUTIME;DEBUG_IO=%d;DEBUG_PIO=%d;",dbglevel,dbglevel);CHKERRQ(ierr);
502     }
503     else {
504       ierr = PetscSNPrintf(ropts_dbg, PETSC_MAX_PATH_LEN, "%sCPUTIME;DEBUG_IO=%d;",dbglevel);CHKERRQ(ierr);
505     }
506   }
507 
508   ierr = PetscSNPrintf(ropts, PETSC_MAX_PATH_LEN, "%s%s%s%s",ropts_par,ropts_dbg,(extra_opts?extra_opts:""),(dm_opts?dm_opts:""));CHKERRQ(ierr);
509   *read_opts = ropts;
510   PetscFunctionReturn(0);
511 }
512 
513 
514 /*@
515   DMMoabLoadFromFile - Creates a DM object by loading the mesh from a user specified file.
516 
517   Collective on MPI_Comm
518 
519   Input Parameters:
520 + comm - The communicator for the DM object
521 . dim - The spatial dimension
522 . filename - The name of the mesh file to be loaded
523 . usrreadopts - The options string to read a MOAB mesh.
524   Reference (Parallel Mesh Initialization: http://www.mcs.anl.gov/~fathom/moab-docs/html/contents.html#fivetwo)
525 
526   Output Parameter:
527 . dm  - The DM object
528 
529   Level: beginner
530 
531 .keywords: DM, create
532 
533 .seealso: DMSetType(), DMCreate(), DMMoabCreateBoxMesh()
534 @*/
535 PetscErrorCode DMMoabLoadFromFile(MPI_Comm comm,PetscInt dim,const char* filename, const char* usrreadopts, DM *dm)
536 {
537   moab::ErrorCode merr;
538   PetscInt        nprocs;
539   DM_Moab        *dmmoab;
540   moab::Interface *mbiface;
541   moab::ParallelComm *pcomm;
542   moab::Range verts,elems;
543   const char *readopts;
544   PetscErrorCode ierr;
545 
546   PetscFunctionBegin;
547   PetscValidPointer(dm,5);
548 
549   /* Create the basic DMMoab object and keep the default parameters created by DM impls */
550   ierr = DMMoabCreateMoab(comm, NULL, NULL, NULL, NULL, dm);CHKERRQ(ierr);
551 
552   /* get all the necessary handles from the private DM object */
553   dmmoab = (DM_Moab*)(*dm)->data;
554   mbiface = dmmoab->mbiface;
555   pcomm = dmmoab->pcomm;
556   nprocs = pcomm->size();
557   /* TODO: Decipher dimension based on the loaded mesh instead of getting from user */
558   dmmoab->dim = dim;
559 
560   /* create a file set to associate all entities in current mesh */
561   merr = dmmoab->mbiface->create_meshset(moab::MESHSET_SET, dmmoab->fileset);MBERR("Creating file set failed", merr);
562 
563   /* add mesh loading options specific to the DM */
564   ierr = DMMoab_GetReadOptions_Private(dmmoab->partition_by_rank, nprocs, dim, dmmoab->read_mode,
565                                         dmmoab->rw_dbglevel, dmmoab->extra_read_options, usrreadopts, &readopts);CHKERRQ(ierr);
566 
567   PetscInfo2(*dm, "Reading file %s with options: %s\n",filename,readopts);
568 
569   /* Load the mesh from a file. */
570   merr = mbiface->load_file(filename, &dmmoab->fileset, readopts);MBERRVM(mbiface,"Reading MOAB file failed.", merr);
571 
572   /* Reassign global IDs on all entities. */
573   merr = pcomm->assign_global_ids(dmmoab->fileset,dim,1,true,true,true);MBERRNM(merr);
574 
575   /* load the local vertices */
576   merr = mbiface->get_entities_by_type(dmmoab->fileset, moab::MBVERTEX, verts, true);MBERRNM(merr);
577   /* load the local elements */
578   merr = mbiface->get_entities_by_dimension(dmmoab->fileset, dim, elems, true);MBERRNM(merr);
579 
580   /* Everything is set up, now just do a tag exchange to update tags
581      on all of the ghost vertexes */
582   merr = pcomm->exchange_tags(dmmoab->ltog_tag,verts);MBERRV(mbiface,merr);
583   merr = pcomm->exchange_tags(dmmoab->ltog_tag,elems);MBERRV(mbiface,merr);
584 
585   merr = pcomm->exchange_ghost_cells(dim,0,1,0,true,true,&dmmoab->fileset);MBERRV(mbiface,merr);
586 
587   merr = pcomm->collective_sync_partition();MBERR("Collective sync failed", merr);
588 
589   PetscInfo3(*dm, "MOAB file '%s' was successfully loaded. Found %D vertices and %D elements.\n", filename, verts.size(), elems.size());
590   ierr = PetscFree(readopts);CHKERRQ(ierr);
591   PetscFunctionReturn(0);
592 }
593 
594