xref: /petsc/src/dm/impls/moab/dmmbutil.cxx (revision dfd57a172ac9fa6c7b5fe6de6ab5df85cefc2996)
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/MergeMesh.hpp>
8 #include <moab/CN.hpp>
9 
10 typedef struct {
11   // options
12   PetscInt  A, B, C, M, N, K, dim;
13   PetscInt  blockSizeVertexXYZ[3];              // Number of element blocks per partition
14   PetscInt  blockSizeElementXYZ[3];
15   PetscReal xyzbounds[6]; // the physical size of the domain
16   bool      newMergeMethod, keep_skins, simplex, adjEnts;
17 
18   // compute params
19   PetscReal dx, dy, dz;
20   PetscInt  NX, NY, NZ, nex, ney, nez;
21   PetscInt  q, xstride, ystride, zstride;
22   PetscBool usrxyzgrid, usrprocgrid, usrrefgrid;
23   PetscInt  fraction, remainder, cumfraction;
24   PetscLogEvent generateMesh, generateElements, generateVertices, parResolve;
25 
26 } DMMoabMeshGeneratorCtx;
27 
28 PetscInt DMMoab_SetTensorElementConnectivity_Private(DMMoabMeshGeneratorCtx& genCtx, PetscInt offset, PetscInt corner, std::vector<PetscInt>& subent_conn, moab::EntityHandle *connectivity)
29 {
30   switch (genCtx.dim) {
31   case 1:
32     subent_conn.resize(2);
33     moab::CN::SubEntityVertexIndices(moab::MBEDGE, 1, 0, subent_conn.data());
34     connectivity[offset + subent_conn[0]] = corner;
35     connectivity[offset + subent_conn[1]] = corner + 1;
36     break;
37   case 2:
38     subent_conn.resize(4);
39     moab::CN::SubEntityVertexIndices(moab::MBQUAD, 2, 0, subent_conn.data());
40     connectivity[offset + subent_conn[0]] = corner;
41     connectivity[offset + subent_conn[1]] = corner + 1;
42     connectivity[offset + subent_conn[2]] = corner + 1 + genCtx.ystride;
43     connectivity[offset + subent_conn[3]] = corner + genCtx.ystride;
44     break;
45   case 3:
46   default:
47     subent_conn.resize(8);
48     moab::CN::SubEntityVertexIndices(moab::MBHEX, 3, 0, subent_conn.data());
49     connectivity[offset + subent_conn[0]] = corner;
50     connectivity[offset + subent_conn[1]] = corner + 1;
51     connectivity[offset + subent_conn[2]] = corner + 1 + genCtx.ystride;
52     connectivity[offset + subent_conn[3]] = corner + genCtx.ystride;
53     connectivity[offset + subent_conn[4]] = corner + genCtx.zstride;
54     connectivity[offset + subent_conn[5]] = corner + 1 + genCtx.zstride;
55     connectivity[offset + subent_conn[6]] = corner + 1 + genCtx.ystride + genCtx.zstride;
56     connectivity[offset + subent_conn[7]] = corner + genCtx.ystride + genCtx.zstride;
57     break;
58   }
59   return subent_conn.size();
60 }
61 
62 PetscInt DMMoab_SetSimplexElementConnectivity_Private(DMMoabMeshGeneratorCtx& genCtx, PetscInt subelem, PetscInt offset, PetscInt corner, std::vector<PetscInt>& subent_conn, moab::EntityHandle *connectivity)
63 {
64   PetscInt A, B, C, D, E, F, G, H, M;
65   const PetscInt trigen_opts = 1; /* 1 - Aligned diagonally to right, 2 - Aligned diagonally to left, 3 - 4 elements per quad */
66   A = corner;
67   B = corner + 1;
68   switch (genCtx.dim) {
69   case 1:
70     subent_conn.resize(2);  /* only linear EDGE supported now */
71     moab::CN::SubEntityVertexIndices(moab::MBEDGE, 1, 0, subent_conn.data());
72     connectivity[offset + subent_conn[0]] = A;
73     connectivity[offset + subent_conn[1]] = B;
74     break;
75   case 2:
76     C = corner + 1 + genCtx.ystride;
77     D = corner +     genCtx.ystride;
78     M = corner + 0.5; /* technically -- need to modify vertex generation */
79     subent_conn.resize(3);  /* only linear TRI supported */
80     moab::CN::SubEntityVertexIndices(moab::MBTRI, 2, 0, subent_conn.data());
81     if (trigen_opts == 1) {
82       if (subelem) { /* 0 1 2 of a QUAD */
83         connectivity[offset + subent_conn[0]] = B;
84         connectivity[offset + subent_conn[1]] = C;
85         connectivity[offset + subent_conn[2]] = A;
86       }
87       else {        /* 2 3 0 of a QUAD */
88         connectivity[offset + subent_conn[0]] = D;
89         connectivity[offset + subent_conn[1]] = A;
90         connectivity[offset + subent_conn[2]] = C;
91       }
92     }
93     else if (trigen_opts == 2) {
94       if (subelem) { /* 0 1 2 of a QUAD */
95         connectivity[offset + subent_conn[0]] = A;
96         connectivity[offset + subent_conn[1]] = B;
97         connectivity[offset + subent_conn[2]] = D;
98       }
99       else {        /* 2 3 0 of a QUAD */
100         connectivity[offset + subent_conn[0]] = C;
101         connectivity[offset + subent_conn[1]] = D;
102         connectivity[offset + subent_conn[2]] = B;
103       }
104     }
105     else {
106       switch (subelem) { /* 0 1 2 of a QUAD */
107       case 0:
108         connectivity[offset + subent_conn[0]] = A;
109         connectivity[offset + subent_conn[1]] = B;
110         connectivity[offset + subent_conn[2]] = M;
111         break;
112       case 1:
113         connectivity[offset + subent_conn[0]] = B;
114         connectivity[offset + subent_conn[1]] = C;
115         connectivity[offset + subent_conn[2]] = M;
116         break;
117       case 2:
118         connectivity[offset + subent_conn[0]] = C;
119         connectivity[offset + subent_conn[1]] = D;
120         connectivity[offset + subent_conn[2]] = M;
121         break;
122       case 3:
123         connectivity[offset + subent_conn[0]] = D;
124         connectivity[offset + subent_conn[1]] = A;
125         connectivity[offset + subent_conn[2]] = M;
126         break;
127       }
128     }
129     break;
130   case 3:
131   default:
132     C = corner + 1 + genCtx.ystride;
133     D = corner +     genCtx.ystride;
134     E = corner +                      genCtx.zstride;
135     F = corner + 1 +                  genCtx.zstride;
136     G = corner + 1 + genCtx.ystride + genCtx.zstride;
137     H = corner +     genCtx.ystride + genCtx.zstride;
138     subent_conn.resize(4);  /* only linear TET supported */
139     moab::CN::SubEntityVertexIndices(moab::MBTET, 3, 0, subent_conn.data());
140     switch (subelem) {
141     case 0: /* 4 3 7 6 of a HEX */
142       connectivity[offset + subent_conn[0]] = E;
143       connectivity[offset + subent_conn[1]] = D;
144       connectivity[offset + subent_conn[2]] = H;
145       connectivity[offset + subent_conn[3]] = G;
146       break;
147     case 1: /* 0 1 2 5 of a HEX */
148       connectivity[offset + subent_conn[0]] = A;
149       connectivity[offset + subent_conn[1]] = B;
150       connectivity[offset + subent_conn[2]] = C;
151       connectivity[offset + subent_conn[3]] = F;
152       break;
153     case 2: /* 0 3 4 5 of a HEX */
154       connectivity[offset + subent_conn[0]] = A;
155       connectivity[offset + subent_conn[1]] = D;
156       connectivity[offset + subent_conn[2]] = E;
157       connectivity[offset + subent_conn[3]] = F;
158       break;
159     case 3: /* 2 6 3 5 of a HEX */
160       connectivity[offset + subent_conn[0]] = C;
161       connectivity[offset + subent_conn[1]] = G;
162       connectivity[offset + subent_conn[2]] = D;
163       connectivity[offset + subent_conn[3]] = F;
164       break;
165     case 4: /* 0 2 3 5 of a HEX */
166       connectivity[offset + subent_conn[0]] = A;
167       connectivity[offset + subent_conn[1]] = C;
168       connectivity[offset + subent_conn[2]] = D;
169       connectivity[offset + subent_conn[3]] = F;
170       break;
171     case 5: /* 3 6 4 5 of a HEX */
172       connectivity[offset + subent_conn[0]] = D;
173       connectivity[offset + subent_conn[1]] = G;
174       connectivity[offset + subent_conn[2]] = E;
175       connectivity[offset + subent_conn[3]] = F;
176       break;
177     }
178     break;
179   }
180   return subent_conn.size();
181 }
182 
183 std::pair<PetscInt, PetscInt> DMMoab_SetElementConnectivity_Private(DMMoabMeshGeneratorCtx& genCtx, PetscInt offset, PetscInt corner, moab::EntityHandle *connectivity)
184 {
185   PetscInt vcount = 0;
186   PetscInt simplices_per_tensor[4] = {0, 1, 2, 6};
187   std::vector<PetscInt> subent_conn;  /* only linear edge, tri, tet supported now */
188   subent_conn.reserve(27);
189   PetscInt m, subelem;
190   if (genCtx.simplex) {
191     subelem = simplices_per_tensor[genCtx.dim];
192     for (m = 0; m < subelem; m++) {
193       vcount = DMMoab_SetSimplexElementConnectivity_Private(genCtx, m, offset, corner, subent_conn, connectivity);
194       offset += vcount;
195     }
196   }
197   else {
198     subelem = 1;
199     vcount = DMMoab_SetTensorElementConnectivity_Private(genCtx, offset, corner, subent_conn, connectivity);
200   }
201   return std::pair<PetscInt, PetscInt>(vcount * subelem, subelem);
202 }
203 
204 PetscErrorCode DMMoab_GenerateVertices_Private(moab::Interface *mbImpl, moab::ReadUtilIface *iface, DMMoabMeshGeneratorCtx& genCtx, PetscInt m, PetscInt n, PetscInt k,
205     PetscInt a, PetscInt b, PetscInt c, moab::Tag& global_id_tag, moab::EntityHandle& startv, moab::Range& uverts)
206 {
207   PetscInt x, y, z, ix, nnodes;
208   PetscErrorCode ierr;
209   PetscInt ii, jj, kk;
210   std::vector<PetscReal*> arrays;
211   PetscInt* gids;
212   moab::ErrorCode merr;
213 
214   PetscFunctionBegin;
215   /* we will generate (q*block+1)^3 vertices, and block^3 hexas; q is 1 for linear, 2 for quadratic
216    * the global id of the vertices will come from m, n, k, a, b, c
217    * x will vary from  m*A*q*block + a*q*block to m*A*q*block+(a+1)*q*block etc.
218    */
219   nnodes = genCtx.blockSizeVertexXYZ[0] * (genCtx.dim > 1 ? genCtx.blockSizeVertexXYZ[1] * (genCtx.dim > 2 ? genCtx.blockSizeVertexXYZ[2] : 1) : 1);
220   ierr = PetscMalloc1(nnodes, &gids);CHKERRQ(ierr);
221 
222   merr = iface->get_node_coords(3, nnodes, 0, startv, arrays);MBERR("Can't get node coords.", merr);
223 
224   /* will start with the lower corner: */
225   /* x = ( m * genCtx.A + a) * genCtx.q * genCtx.blockSizeElementXYZ[0]; */
226   /* y = ( n * genCtx.B + b) * genCtx.q * genCtx.blockSizeElementXYZ[1]; */
227   /* z = ( k * genCtx.C + c) * genCtx.q * genCtx.blockSizeElementXYZ[2]; */
228 
229   x = ( m * genCtx.A + a) * genCtx.q;
230   y = ( n * genCtx.B + b) * genCtx.q;
231   z = ( k * genCtx.C + c) * genCtx.q;
232   PetscInfo3(NULL, "Starting offset for coordinates := %d, %d, %d\n", x, y, z);
233   ix = 0;
234   moab::Range verts(startv, startv + nnodes - 1);
235   for (kk = 0; kk < (genCtx.dim > 2 ? genCtx.blockSizeVertexXYZ[2] : 1); kk++) {
236     for (jj = 0; jj < (genCtx.dim > 1 ? genCtx.blockSizeVertexXYZ[1] : 1); jj++) {
237       for (ii = 0; ii < genCtx.blockSizeVertexXYZ[0]; ii++, ix++) {
238         /* set coordinates for the vertices */
239         arrays[0][ix] = (x + ii) * genCtx.dx + genCtx.xyzbounds[0];
240         arrays[1][ix] = (y + jj) * genCtx.dy + genCtx.xyzbounds[2];
241         arrays[2][ix] = (z + kk) * genCtx.dz + genCtx.xyzbounds[4];
242         PetscInfo3(NULL, "Creating vertex with coordinates := %f, %f, %f\n", arrays[0][ix], arrays[1][ix], arrays[2][ix]);
243 
244         /* If we want to set some tags on the vertices -> use the following entity handle definition:
245            moab::EntityHandle v = startv + ix;
246         */
247         /* compute the global ID for vertex */
248         gids[ix] = 1 + (x + ii) + (y + jj) * genCtx.NX + (z + kk) * (genCtx.NX * genCtx.NY);
249       }
250     }
251   }
252   /* set global ID data on vertices */
253   mbImpl->tag_set_data(global_id_tag, verts, &gids[0]);
254   verts.swap(uverts);
255   ierr = PetscFree(gids);CHKERRQ(ierr);
256   PetscFunctionReturn(0);
257 }
258 
259 PetscErrorCode DMMoab_GenerateElements_Private(moab::Interface* mbImpl, moab::ReadUtilIface* iface, DMMoabMeshGeneratorCtx& genCtx, PetscInt m, PetscInt n, PetscInt k,
260     PetscInt a, PetscInt b, PetscInt c, moab::Tag& global_id_tag, moab::EntityHandle startv, moab::Range& cells)
261 {
262   moab::ErrorCode merr;
263   PetscInt ix, ie, xe, ye, ze;
264   PetscInt ii, jj, kk, nvperelem;
265   PetscInt simplices_per_tensor[4] = {0, 1, 2, 6};
266   PetscInt ntensorelems = genCtx.blockSizeElementXYZ[0] * (genCtx.dim > 1 ? genCtx.blockSizeElementXYZ[1] * (genCtx.dim > 2 ? genCtx.blockSizeElementXYZ[2] : 1) : 1); /*pow(genCtx.blockSizeElement,genCtx.dim);*/
267   PetscInt nelems = ntensorelems;
268   moab::EntityHandle starte; /* connectivity */
269   moab::EntityHandle* conn;
270 
271   PetscFunctionBegin;
272   switch (genCtx.dim) {
273   case 1:
274     nvperelem = 2;
275     merr = iface->get_element_connect(nelems, 2, moab::MBEDGE, 0, starte, conn);MBERR("Can't get EDGE2 element connectivity.", merr);
276     break;
277   case 2:
278     if (genCtx.simplex) {
279       nvperelem = 3;
280       nelems = ntensorelems * simplices_per_tensor[genCtx.dim];
281       merr = iface->get_element_connect(nelems, 3, moab::MBTRI, 0, starte, conn);MBERR("Can't get TRI3 element connectivity.", merr);
282     }
283     else {
284       nvperelem = 4;
285       merr = iface->get_element_connect(nelems, 4, moab::MBQUAD, 0, starte, conn);MBERR("Can't get QUAD4 element connectivity.", merr);
286     }
287     break;
288   case 3:
289   default:
290     if (genCtx.simplex) {
291       nvperelem = 4;
292       nelems = ntensorelems * simplices_per_tensor[genCtx.dim];
293       merr = iface->get_element_connect(nelems, 4, moab::MBTET, 0, starte, conn);MBERR("Can't get TET4 element connectivity.", merr);
294     }
295     else {
296       nvperelem = 8;
297       merr = iface->get_element_connect(nelems, 8, moab::MBHEX, 0, starte, conn);MBERR("Can't get HEX8 element connectivity.", merr);
298     }
299     break;
300   }
301 
302   ix = ie = 0; /* index now in the elements, for global ids */
303 
304   /* create a temporary range to store local element handles */
305   moab::Range tmp(starte, starte + nelems - 1);
306   std::vector<PetscInt> gids(nelems);
307 
308   /* identify the elements at the lower corner, for their global ids */
309   xe = m * genCtx.A * genCtx.blockSizeElementXYZ[0] + a * genCtx.blockSizeElementXYZ[0];
310   ye = (genCtx.dim > 1 ? n * genCtx.B * genCtx.blockSizeElementXYZ[1] + b * genCtx.blockSizeElementXYZ[1] : 0);
311   ze = (genCtx.dim > 2 ? k * genCtx.C * genCtx.blockSizeElementXYZ[2] + c * genCtx.blockSizeElementXYZ[2] : 0);
312 
313   /* create owned elements requested by genCtx */
314   for (kk = 0; kk < (genCtx.dim > 2 ? genCtx.blockSizeElementXYZ[2] : 1); kk++) {
315     for (jj = 0; jj < (genCtx.dim > 1 ? genCtx.blockSizeElementXYZ[1] : 1); jj++) {
316       for (ii = 0; ii < genCtx.blockSizeElementXYZ[0]; ii++) {
317 
318         moab::EntityHandle corner = startv + genCtx.q * ii + genCtx.q * jj * genCtx.ystride + genCtx.q * kk * genCtx.zstride;
319 
320         std::pair<PetscInt, PetscInt> entoffset = DMMoab_SetElementConnectivity_Private(genCtx, ix, corner, conn);
321 
322         for (PetscInt j = 0; j < entoffset.second; j++) {
323           /* The entity handle for the particular element -> if we want to set some tags is
324              moab::EntityHandle eh = starte + ie + j;
325           */
326           gids[ie + j] = 1 + ((xe + ii) + (ye + jj) * genCtx.nex + (ze + kk) * (genCtx.nex * genCtx.ney));
327           /* gids[ie+j] = ie + j + ((xe + ii) + (ye + jj) * genCtx.nex + (ze + kk) * (genCtx.nex * genCtx.ney)); */
328           /* gids[ie+j] = 1 + ie; */
329           /* ie++; */
330         }
331 
332         ix += entoffset.first;
333         ie += entoffset.second;
334       }
335     }
336   }
337   if (genCtx.adjEnts) { /* we need to update adjacencies now, because some elements are new */
338     merr = iface->update_adjacencies(starte, nelems, nvperelem, conn);MBERR("Can't update adjacencies", merr);
339   }
340   tmp.swap(cells);
341   merr = mbImpl->tag_set_data(global_id_tag, cells, &gids[0]);MBERR("Can't set global ids to elements.", merr);
342   PetscFunctionReturn(0);
343 }
344 
345 PetscErrorCode DMMBUtil_InitializeOptions(DMMoabMeshGeneratorCtx& genCtx, PetscInt dim, PetscBool simplex, PetscInt rank, PetscInt nprocs, const PetscReal* bounds, PetscInt nelems)
346 {
347   PetscFunctionBegin;
348   /* Initialize all genCtx data */
349   genCtx.dim = dim;
350   genCtx.simplex = simplex;
351   genCtx.newMergeMethod = genCtx.keep_skins = genCtx.adjEnts = true;
352   /* determine other global quantities for the mesh used for nodes increments */
353   genCtx.q = 1;
354   genCtx.fraction = genCtx.remainder = genCtx.cumfraction = 0;
355 
356   if (!genCtx.usrxyzgrid) { /* not overridden by genCtx - assume nele equally and that genCtx wants a uniform cube mesh */
357 
358     genCtx.fraction = nelems / nprocs; /* partition only by the largest dimension */
359     genCtx.remainder = nelems % nprocs; /* remainder after partition which gets evenly distributed by round-robin */
360     genCtx.cumfraction = (rank > 0 ? (genCtx.fraction) * (rank) + (rank - 1 < genCtx.remainder ? rank : genCtx.remainder) : 0);
361     if (rank < genCtx.remainder)    /* This process gets "fraction+1" elements */
362       genCtx.fraction++;
363 
364     PetscInfo3(NULL, "Fraction = %D, Remainder = %D, Cumulative fraction = %D\n", genCtx.fraction, genCtx.remainder, genCtx.cumfraction);
365     switch (genCtx.dim) {
366     case 1:
367       genCtx.blockSizeElementXYZ[0] = genCtx.fraction;
368       genCtx.blockSizeElementXYZ[1] = 1;
369       genCtx.blockSizeElementXYZ[2] = 1;
370       break;
371     case 2:
372       genCtx.blockSizeElementXYZ[0] = nelems;
373       genCtx.blockSizeElementXYZ[1] = genCtx.fraction;
374       genCtx.blockSizeElementXYZ[2] = 1;
375       break;
376     case 3:
377     default:
378       genCtx.blockSizeElementXYZ[0] = nelems;
379       genCtx.blockSizeElementXYZ[1] = nelems;
380       genCtx.blockSizeElementXYZ[2] = genCtx.fraction;
381       break;
382     }
383   }
384 
385   /* partition only by the largest dimension */
386   /* Total number of local elements := genCtx.blockSizeElementXYZ[0]*(genCtx.dim>1? genCtx.blockSizeElementXYZ[1]*(genCtx.dim>2 ? genCtx.blockSizeElementXYZ[2]:1) :1); */
387   if (bounds) {
388     for (PetscInt i = 0; i < 6; i++)
389       genCtx.xyzbounds[i] = bounds[i];
390   }
391   else {
392     genCtx.xyzbounds[0] = genCtx.xyzbounds[2] = genCtx.xyzbounds[4] = 0.0;
393     genCtx.xyzbounds[1] = genCtx.xyzbounds[3] = genCtx.xyzbounds[5] = 1.0;
394   }
395 
396   if (!genCtx.usrprocgrid) {
397     switch (genCtx.dim) {
398     case 1:
399       genCtx.M = nprocs;
400       genCtx.N = genCtx.K = 1;
401       break;
402     case 2:
403       genCtx.N = nprocs;
404       genCtx.M = genCtx.K = 1;
405       break;
406     default:
407       genCtx.K = nprocs;
408       genCtx.M = genCtx.N = 1;
409       break;
410     }
411   }
412 
413   if (!genCtx.usrrefgrid) {
414     genCtx.A = genCtx.B = genCtx.C = 1;
415   }
416 
417   /* more default values */
418   genCtx.nex = genCtx.ney = genCtx.nez = 0;
419   genCtx.xstride = genCtx.ystride = genCtx.zstride = 0;
420   genCtx.NX = genCtx.NY = genCtx.NZ = 0;
421   genCtx.nex = genCtx.ney = genCtx.nez = 0;
422   genCtx.blockSizeVertexXYZ[0] = genCtx.blockSizeVertexXYZ[1] = genCtx.blockSizeVertexXYZ[2] = 1;
423 
424   switch (genCtx.dim) {
425   case 3:
426     genCtx.blockSizeVertexXYZ[0] = genCtx.q * genCtx.blockSizeElementXYZ[0] + 1;
427     genCtx.blockSizeVertexXYZ[1] = genCtx.q * genCtx.blockSizeElementXYZ[1] + 1;
428     genCtx.blockSizeVertexXYZ[2] = genCtx.q * genCtx.blockSizeElementXYZ[2] + 1;
429 
430     genCtx.nex = genCtx.M * genCtx.A * genCtx.blockSizeElementXYZ[0];   /* number of elements in x direction, used for global id on element */
431     genCtx.dx = (genCtx.xyzbounds[1] - genCtx.xyzbounds[0]) / (nelems * genCtx.q); /* distance between 2 nodes in x direction */
432     genCtx.NX = (genCtx.q * genCtx.nex + 1);
433     genCtx.xstride = 1;
434     genCtx.ney = genCtx.N * genCtx.B * genCtx.blockSizeElementXYZ[1];  /* number of elements in y direction  .... */
435     genCtx.dy = (genCtx.xyzbounds[3] - genCtx.xyzbounds[2]) / (nelems * genCtx.q); /* distance between 2 nodes in y direction */
436     genCtx.NY = (genCtx.q * genCtx.ney + 1);
437     genCtx.ystride = genCtx.blockSizeVertexXYZ[0];
438     genCtx.nez = genCtx.K * genCtx.C * genCtx.blockSizeElementXYZ[2];  /* number of elements in z direction  .... */
439     genCtx.dz = (genCtx.xyzbounds[5] - genCtx.xyzbounds[4]) / (nelems * genCtx.q); /* distance between 2 nodes in z direction */
440     genCtx.NZ = (genCtx.q * genCtx.nez + 1);
441     genCtx.zstride = genCtx.blockSizeVertexXYZ[0] * genCtx.blockSizeVertexXYZ[1];
442     break;
443   case 2:
444     genCtx.blockSizeVertexXYZ[0] = genCtx.q * genCtx.blockSizeElementXYZ[0] + 1;
445     genCtx.blockSizeVertexXYZ[1] = genCtx.q * genCtx.blockSizeElementXYZ[1] + 1;
446     genCtx.blockSizeVertexXYZ[2] = 0;
447 
448     genCtx.nex = genCtx.M * genCtx.A * genCtx.blockSizeElementXYZ[0];   /* number of elements in x direction, used for global id on element */
449     genCtx.dx = (genCtx.xyzbounds[1] - genCtx.xyzbounds[0]) / (genCtx.nex * genCtx.q); /* distance between 2 nodes in x direction */
450     genCtx.NX = (genCtx.q * genCtx.nex + 1);
451     genCtx.xstride = 1;
452     genCtx.ney = genCtx.N * genCtx.B * genCtx.blockSizeElementXYZ[1];  /* number of elements in y direction  .... */
453     genCtx.dy = (genCtx.xyzbounds[3] - genCtx.xyzbounds[2]) / (nelems * genCtx.q); /* distance between 2 nodes in y direction */
454     genCtx.NY = (genCtx.q * genCtx.ney + 1);
455     genCtx.ystride = genCtx.blockSizeVertexXYZ[0];
456     break;
457   case 1:
458     genCtx.blockSizeVertexXYZ[1] = genCtx.blockSizeVertexXYZ[2] = 0;
459     genCtx.blockSizeVertexXYZ[0] = genCtx.q * genCtx.blockSizeElementXYZ[0] + 1;
460 
461     genCtx.nex = genCtx.M * genCtx.A * genCtx.blockSizeElementXYZ[0];   /* number of elements in x direction, used for global id on element */
462     genCtx.dx = (genCtx.xyzbounds[1] - genCtx.xyzbounds[0]) / (nelems * genCtx.q); /* distance between 2 nodes in x direction */
463     genCtx.NX = (genCtx.q * genCtx.nex + 1);
464     genCtx.xstride = 1;
465     break;
466   }
467 
468   /* Lets check for some valid input */
469   if (genCtx.dim < 1 || genCtx.dim > 3) SETERRQ1(PETSC_COMM_WORLD, PETSC_ERR_ARG_OUTOFRANGE, "Invalid topological dimension specified: %d.\n", genCtx.dim);
470   if (genCtx.M * genCtx.N * genCtx.K != nprocs) SETERRQ4(PETSC_COMM_WORLD, PETSC_ERR_ARG_OUTOFRANGE, "Invalid [m, n, k] data: %d, %d, %d. Product must be equal to global size = %d.\n", genCtx.M, genCtx.N, genCtx.K, nprocs);
471   /* validate the bounds data */
472   if (genCtx.xyzbounds[0] >= genCtx.xyzbounds[1]) SETERRQ2(PETSC_COMM_WORLD, PETSC_ERR_ARG_OUTOFRANGE, "X-dim: Left boundary cannot be greater than right. [%G >= %G]\n", genCtx.xyzbounds[0], genCtx.xyzbounds[1]);
473   if (genCtx.dim > 1 && (genCtx.xyzbounds[2] >= genCtx.xyzbounds[3])) SETERRQ2(PETSC_COMM_WORLD, PETSC_ERR_ARG_OUTOFRANGE, "Y-dim: Left boundary cannot be greater than right. [%G >= %G]\n", genCtx.xyzbounds[2], genCtx.xyzbounds[3]);
474   if (genCtx.dim > 2 && (genCtx.xyzbounds[4] >= genCtx.xyzbounds[5])) SETERRQ2(PETSC_COMM_WORLD, PETSC_ERR_ARG_OUTOFRANGE, "Z-dim: Left boundary cannot be greater than right. [%G >= %G]\n", genCtx.xyzbounds[4], genCtx.xyzbounds[5]);
475 
476   PetscInfo3(NULL, "Local elements:= %d, %d, %d\n", genCtx.blockSizeElementXYZ[0], genCtx.blockSizeElementXYZ[1], genCtx.blockSizeElementXYZ[2]);
477   PetscInfo3(NULL, "Local vertices:= %d, %d, %d\n", genCtx.blockSizeVertexXYZ[0], genCtx.blockSizeVertexXYZ[1], genCtx.blockSizeVertexXYZ[2]);
478   PetscInfo3(NULL, "Local blocks/processors := %d, %d, %d\n", genCtx.A, genCtx.B, genCtx.C);
479   PetscInfo3(NULL, "Local processors := %d, %d, %d\n", genCtx.M, genCtx.N, genCtx.K);
480   PetscInfo3(NULL, "Local nexyz:= %d, %d, %d\n", genCtx.nex, genCtx.ney, genCtx.nez);
481   PetscInfo3(NULL, "Local delxyz:= %g, %g, %g\n", genCtx.dx, genCtx.dy, genCtx.dz);
482   PetscInfo3(NULL, "Local strides:= %d, %d, %d\n", genCtx.xstride, genCtx.ystride, genCtx.zstride);
483   PetscFunctionReturn(0);
484 }
485 
486 /*@C
487   DMMoabCreateBoxMesh - Creates a mesh on the tensor product (box) of intervals with genCtx specified bounds.
488 
489   Collective
490 
491   Input Parameters:
492 + comm - The communicator for the DM object
493 . dim - The spatial dimension
494 . 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
495 . nele - The number of discrete elements in each direction
496 - user_nghost - The number of ghosted layers needed in the partitioned mesh
497 
498   Output Parameter:
499 . dm  - The DM object
500 
501   Level: beginner
502 
503 .seealso: DMSetType(), DMCreate(), DMMoabLoadFromFile()
504 @*/
505 PetscErrorCode DMMoabCreateBoxMesh(MPI_Comm comm, PetscInt dim, PetscBool useSimplex, const PetscReal* bounds, PetscInt nele, PetscInt nghost, DM *dm)
506 {
507   PetscErrorCode         ierr;
508   moab::ErrorCode        merr;
509   PetscInt               a, b, c, n, global_size, global_rank;
510   DM_Moab               *dmmoab;
511   moab::Interface       *mbImpl;
512 #ifdef MOAB_HAVE_MPI
513   moab::ParallelComm    *pcomm;
514 #endif
515   moab::ReadUtilIface   *readMeshIface;
516   moab::Range            verts, cells, edges, faces, adj, dim3, dim2;
517   DMMoabMeshGeneratorCtx genCtx;
518   const PetscInt         npts = nele + 1;    /* Number of points in every dimension */
519 
520   moab::Tag              global_id_tag, part_tag, geom_tag, mat_tag, dir_tag, neu_tag;
521   moab::Range            ownedvtx, ownedelms, localvtxs, localelms;
522   moab::EntityHandle     regionset;
523   PetscInt               ml = 0, nl = 0, kl = 0;
524 
525   PetscFunctionBegin;
526   if (dim < 1 || dim > 3) SETERRQ(PETSC_COMM_WORLD, PETSC_ERR_ARG_OUTOFRANGE, "Invalid dimension argument for mesh: dim=[1,3].\n");
527 
528   ierr = PetscLogEventRegister("GenerateMesh", DM_CLASSID,   &genCtx.generateMesh);CHKERRQ(ierr);
529   ierr = PetscLogEventRegister("AddVertices", DM_CLASSID,   &genCtx.generateVertices);CHKERRQ(ierr);
530   ierr = PetscLogEventRegister("AddElements", DM_CLASSID,   &genCtx.generateElements);CHKERRQ(ierr);
531   ierr = PetscLogEventRegister("ParResolve", DM_CLASSID,   &genCtx.parResolve);CHKERRQ(ierr);
532   ierr = PetscLogEventBegin(genCtx.generateMesh, 0, 0, 0, 0);CHKERRQ(ierr);
533   ierr = MPI_Comm_size(comm, &global_size);CHKERRMPI(ierr);
534   /* total number of vertices in all dimensions */
535   n = pow(npts, dim);
536 
537   /* do some error checking */
538   if (n < 2) SETERRQ(PETSC_COMM_WORLD, PETSC_ERR_ARG_OUTOFRANGE, "Number of points must be >= 2.\n");
539   if (global_size > n) SETERRQ(PETSC_COMM_WORLD, PETSC_ERR_ARG_OUTOFRANGE, "Number of processors must be less than or equal to number of elements.\n");
540   if (nghost < 0) SETERRQ(PETSC_COMM_WORLD, PETSC_ERR_ARG_OUTOFRANGE, "Number of ghost layers cannot be negative.\n");
541 
542   /* Create the basic DMMoab object and keep the default parameters created by DM impls */
543   ierr = DMMoabCreateMoab(comm, NULL, NULL, NULL, dm);CHKERRQ(ierr);
544 
545   /* get all the necessary handles from the private DM object */
546   dmmoab = (DM_Moab*)(*dm)->data;
547   mbImpl = dmmoab->mbiface;
548 #ifdef MOAB_HAVE_MPI
549   pcomm = dmmoab->pcomm;
550   global_rank = pcomm->rank();
551 #else
552   global_rank = 0;
553   global_size = 1;
554 #endif
555   global_id_tag = dmmoab->ltog_tag;
556   dmmoab->dim = dim;
557   dmmoab->nghostrings = nghost;
558   dmmoab->refct = 1;
559 
560   /* create a file set to associate all entities in current mesh */
561   merr = mbImpl->create_meshset(moab::MESHSET_SET, dmmoab->fileset);MBERR("Creating file set failed", merr);
562 
563   /* No errors yet; proceed with building the mesh */
564   merr = mbImpl->query_interface(readMeshIface);MBERRNM(merr);
565 
566   genCtx.M = genCtx.N = genCtx.K = 1;
567   genCtx.A = genCtx.B = genCtx.C = 1;
568   genCtx.blockSizeElementXYZ[0] = 0;
569   genCtx.blockSizeElementXYZ[1] = 0;
570   genCtx.blockSizeElementXYZ[2] = 0;
571 
572   ierr = PetscOptionsBegin(comm, "", "DMMoab Creation Options", "DMMOAB");CHKERRQ(ierr);
573   /* Handle DMMoab spatial resolution */
574   ierr = PetscOptionsInt("-dmb_grid_x", "Number of grid points in x direction", "DMMoabSetSizes", genCtx.blockSizeElementXYZ[0], &genCtx.blockSizeElementXYZ[0], &genCtx.usrxyzgrid);CHKERRQ(ierr);
575   if (dim > 1) {ierr = PetscOptionsInt("-dmb_grid_y", "Number of grid points in y direction", "DMMoabSetSizes", genCtx.blockSizeElementXYZ[1], &genCtx.blockSizeElementXYZ[1], &genCtx.usrxyzgrid);CHKERRQ(ierr);}
576   if (dim > 2) {ierr = PetscOptionsInt("-dmb_grid_z", "Number of grid points in z direction", "DMMoabSetSizes", genCtx.blockSizeElementXYZ[2], &genCtx.blockSizeElementXYZ[2], &genCtx.usrxyzgrid);CHKERRQ(ierr);}
577 
578   /* Handle DMMoab parallel distibution */
579   ierr = PetscOptionsInt("-dmb_processors_x", "Number of processors in x direction", "DMMoabSetNumProcs", genCtx.M, &genCtx.M, &genCtx.usrprocgrid);CHKERRQ(ierr);
580   if (dim > 1) {ierr = PetscOptionsInt("-dmb_processors_y", "Number of processors in y direction", "DMMoabSetNumProcs", genCtx.N, &genCtx.N, &genCtx.usrprocgrid);CHKERRQ(ierr);}
581   if (dim > 2) {ierr = PetscOptionsInt("-dmb_processors_z", "Number of processors in z direction", "DMMoabSetNumProcs", genCtx.K, &genCtx.K, &genCtx.usrprocgrid);CHKERRQ(ierr);}
582 
583   /* Handle DMMoab block refinement */
584   ierr = PetscOptionsInt("-dmb_refine_x", "Number of refinement blocks in x direction", "DMMoabSetRefinement", genCtx.A, &genCtx.A, &genCtx.usrrefgrid);CHKERRQ(ierr);
585   if (dim > 1) {ierr = PetscOptionsInt("-dmb_refine_y", "Number of refinement blocks in y direction", "DMMoabSetRefinement", genCtx.B, &genCtx.B, &genCtx.usrrefgrid);CHKERRQ(ierr);}
586   if (dim > 2) {ierr = PetscOptionsInt("-dmb_refine_z", "Number of refinement blocks in z direction", "DMMoabSetRefinement", genCtx.C, &genCtx.C, &genCtx.usrrefgrid);CHKERRQ(ierr);}
587   PetscOptionsEnd();
588 
589   ierr = DMMBUtil_InitializeOptions(genCtx, dim, useSimplex, global_rank, global_size, bounds, nele);CHKERRQ(ierr);
590 
591   //if (nele<nprocs) SETERRQ2(PETSC_COMM_WORLD,PETSC_ERR_ARG_OUTOFRANGE,"The dimensional discretization size should be greater or equal to number of processors: %D < %D",nele,nprocs);
592 
593   if (genCtx.adjEnts) genCtx.keep_skins = true; /* do not delete anything - consumes more memory */
594 
595   /* determine m, n, k for processor rank */
596   ml = nl = kl = 0;
597   switch (genCtx.dim) {
598   case 1:
599     ml = (genCtx.cumfraction);
600     break;
601   case 2:
602     nl = (genCtx.cumfraction);
603     break;
604   default:
605     kl = (genCtx.cumfraction) / genCtx.q / genCtx.blockSizeElementXYZ[2] / genCtx.C; //genCtx.K
606     break;
607   }
608 
609   /*
610    * so there are a total of M * A * blockSizeElement elements in x direction (so M * A * blockSizeElement + 1 verts in x direction)
611    * so there are a total of N * B * blockSizeElement elements in y direction (so N * B * blockSizeElement + 1 verts in y direction)
612    * so there are a total of K * C * blockSizeElement elements in z direction (so K * C * blockSizeElement + 1 verts in z direction)
613 
614    * there are ( M * A blockSizeElement)      *  ( N * B * blockSizeElement)      * (K * C * blockSizeElement)    hexas
615    * there are ( M * A * blockSizeElement + 1) *  ( N * B * blockSizeElement + 1) * (K * C * blockSizeElement + 1) vertices
616    * x is the first dimension that varies
617    */
618 
619   /* generate the block at (a, b, c); it will represent a partition , it will get a partition tag */
620   PetscInt dum_id = -1;
621   merr = mbImpl->tag_get_handle("GLOBAL_ID", 1, moab::MB_TYPE_INTEGER, global_id_tag);MBERR("Getting Global_ID Tag handle failed", merr);
622 
623   merr = mbImpl->tag_get_handle(MATERIAL_SET_TAG_NAME, 1, moab::MB_TYPE_INTEGER, mat_tag);MBERR("Getting Material set Tag handle failed", merr);
624   merr = mbImpl->tag_get_handle(DIRICHLET_SET_TAG_NAME, 1, moab::MB_TYPE_INTEGER, dir_tag);MBERR("Getting Dirichlet set Tag handle failed", merr);
625   merr = mbImpl->tag_get_handle(NEUMANN_SET_TAG_NAME, 1, moab::MB_TYPE_INTEGER, neu_tag);MBERR("Getting Neumann set Tag handle failed", merr);
626 
627   merr = mbImpl->tag_get_handle("PARALLEL_PARTITION", 1, moab::MB_TYPE_INTEGER, part_tag, moab::MB_TAG_CREAT | moab::MB_TAG_SPARSE, &dum_id);MBERR("Getting Partition Tag handle failed", merr);
628 
629   /* lets create some sets */
630   merr = mbImpl->tag_get_handle(GEOM_DIMENSION_TAG_NAME, 1, moab::MB_TYPE_INTEGER, geom_tag, moab::MB_TAG_CREAT | moab::MB_TAG_SPARSE, &dum_id);MBERRNM(merr);
631   merr = mbImpl->create_meshset(moab::MESHSET_SET, regionset);MBERRNM(merr);
632   ierr = PetscLogEventEnd(genCtx.generateMesh, 0, 0, 0, 0);CHKERRQ(ierr);
633 
634   for (a = 0; a < (genCtx.dim > 0 ? genCtx.A : genCtx.A); a++) {
635     for (b = 0; b < (genCtx.dim > 1 ? genCtx.B : 1); b++) {
636       for (c = 0; c < (genCtx.dim > 2 ? genCtx.C : 1); c++) {
637 
638         moab::EntityHandle startv;
639 
640         ierr = PetscLogEventBegin(genCtx.generateVertices, 0, 0, 0, 0);CHKERRQ(ierr);
641         ierr = DMMoab_GenerateVertices_Private(mbImpl, readMeshIface, genCtx, ml, nl, kl, a, b, c, global_id_tag, startv, verts);CHKERRQ(ierr);
642         ierr = PetscLogEventEnd(genCtx.generateVertices, 0, 0, 0, 0);CHKERRQ(ierr);
643 
644         ierr = PetscLogEventBegin(genCtx.generateElements, 0, 0, 0, 0);CHKERRQ(ierr);
645         ierr = DMMoab_GenerateElements_Private(mbImpl, readMeshIface, genCtx, ml, nl, kl, a, b, c, global_id_tag, startv, cells);CHKERRQ(ierr);
646         ierr = PetscLogEventEnd(genCtx.generateElements, 0, 0, 0, 0);CHKERRQ(ierr);
647 
648         PetscInt part_num = 0;
649         switch (genCtx.dim) {
650         case 3:
651           part_num += (c + kl * genCtx.C) * (genCtx.M * genCtx.A * genCtx.N * genCtx.B);
652         case 2:
653           part_num += (b + nl * genCtx.B) * (genCtx.M * genCtx.A);
654         case 1:
655           part_num += (a + ml * genCtx.A);
656           break;
657         }
658 
659         moab::EntityHandle part_set;
660         merr = mbImpl->create_meshset(moab::MESHSET_SET, part_set);MBERR("Can't create mesh set.", merr);
661 
662         merr = mbImpl->add_entities(part_set, verts);MBERR("Can't add vertices to set.", merr);
663         merr = mbImpl->add_entities(part_set, cells);MBERR("Can't add entities to set.", merr);
664         merr = mbImpl->add_entities(regionset, cells);MBERR("Can't add entities to set.", merr);
665 
666         /* if needed, add all edges and faces */
667         if (genCtx.adjEnts)
668         {
669           if (genCtx.dim > 1) {
670             merr = mbImpl->get_adjacencies(cells, 1, true, edges, moab::Interface::UNION);MBERR("Can't get edges", merr);
671             merr = mbImpl->add_entities(part_set, edges);MBERR("Can't add edges to partition set.", merr);
672           }
673           if (genCtx.dim > 2) {
674             merr = mbImpl->get_adjacencies(cells, 2, true, faces, moab::Interface::UNION);MBERR("Can't get faces", merr);
675             merr = mbImpl->add_entities(part_set, faces);MBERR("Can't add faces to partition set.", merr);
676           }
677           edges.clear();
678           faces.clear();
679         }
680         verts.clear(); cells.clear();
681 
682         merr = mbImpl->tag_set_data(part_tag, &part_set, 1, &part_num);MBERR("Can't set part tag on set", merr);
683         if (dmmoab->fileset) {
684           merr = mbImpl->add_parent_child(dmmoab->fileset, part_set);MBERR("Can't add part set to file set.", merr);
685           merr = mbImpl->unite_meshset(dmmoab->fileset, part_set);MBERRNM(merr);
686         }
687         merr = mbImpl->add_entities(dmmoab->fileset, &part_set, 1);MBERRNM(merr);
688       }
689     }
690   }
691 
692   merr = mbImpl->add_parent_child(dmmoab->fileset, regionset);MBERRNM(merr);
693 
694   /* Only in parallel: resolve shared entities between processors and exchange ghost layers */
695   if (global_size > 1) {
696 
697     ierr = PetscLogEventBegin(genCtx.parResolve, 0, 0, 0, 0);CHKERRQ(ierr);
698 
699     merr = mbImpl->get_entities_by_dimension(dmmoab->fileset, genCtx.dim, cells);MBERR("Can't get all d-dimensional elements.", merr);
700     merr = mbImpl->get_entities_by_dimension(dmmoab->fileset, 0, verts);MBERR("Can't get all vertices.", merr);
701 
702     if (genCtx.A * genCtx.B * genCtx.C != 1) { //  merge needed
703       moab::MergeMesh mm(mbImpl);
704       if (genCtx.newMergeMethod) {
705         merr = mm.merge_using_integer_tag(verts, global_id_tag);MBERR("Can't merge with GLOBAL_ID tag", merr);
706       }
707       else {
708         merr = mm.merge_entities(cells, 0.0001);MBERR("Can't merge with coordinates", merr);
709       }
710     }
711 
712 #ifdef MOAB_HAVE_MPI
713     /* check the handles */
714     merr = pcomm->check_all_shared_handles();MBERRV(mbImpl, merr);
715 
716     /* resolve the shared entities by exchanging information to adjacent processors */
717     merr = pcomm->resolve_shared_ents(dmmoab->fileset, cells, dim, dim - 1, NULL, &global_id_tag);MBERRV(mbImpl, merr);
718     if (dmmoab->fileset) {
719       merr = pcomm->exchange_ghost_cells(dim, 0, nghost, dim, true, false, &dmmoab->fileset);MBERRV(mbImpl, merr);
720     }
721     else {
722       merr = pcomm->exchange_ghost_cells(dim, 0, nghost, dim, true, false);MBERRV(mbImpl, merr);
723     }
724 
725     /* Reassign global IDs on all entities. */
726     merr = pcomm->assign_global_ids(dmmoab->fileset, dim, 1, false, true, false);MBERRNM(merr);
727 #endif
728 
729     ierr = PetscLogEventEnd(genCtx.parResolve, 0, 0, 0, 0);CHKERRQ(ierr);
730   }
731 
732   if (!genCtx.keep_skins) { // default is to delete the 1- and 2-dimensional entities
733     // delete all quads and edges
734     moab::Range toDelete;
735     if (genCtx.dim > 1) {
736       merr = mbImpl->get_entities_by_dimension(dmmoab->fileset, 1, toDelete);MBERR("Can't get edges", merr);
737     }
738 
739     if (genCtx.dim > 2) {
740       merr = mbImpl->get_entities_by_dimension(dmmoab->fileset, 2, toDelete);MBERR("Can't get faces", merr);
741     }
742 
743 #ifdef MOAB_HAVE_MPI
744     merr = dmmoab->pcomm->delete_entities(toDelete) ;MBERR("Can't delete entities", merr);
745 #endif
746   }
747 
748   /* set geometric dimension tag for regions */
749   merr = mbImpl->tag_set_data(geom_tag, &regionset, 1, &dmmoab->dim);MBERRNM(merr);
750   /* set default material ID for regions */
751   int default_material = 1;
752   merr = mbImpl->tag_set_data(mat_tag, &regionset, 1, &default_material);MBERRNM(merr);
753   /*
754     int default_dbc = 0;
755     merr = mbImpl->tag_set_data(dir_tag, &vertexset, 1, &default_dbc);MBERRNM(merr);
756   */
757   PetscFunctionReturn(0);
758 }
759 
760 PetscErrorCode DMMoab_GetReadOptions_Private(PetscBool by_rank, PetscInt numproc, PetscInt dim, PetscInt nghost, MoabReadMode mode, PetscInt dbglevel, const char* dm_opts, const char* extra_opts, const char** read_opts)
761 {
762   char           *ropts;
763   char           ropts_par[PETSC_MAX_PATH_LEN], ropts_pargh[PETSC_MAX_PATH_LEN];
764   char           ropts_dbg[PETSC_MAX_PATH_LEN];
765   PetscErrorCode ierr;
766 
767   PetscFunctionBegin;
768   ierr = PetscMalloc1(PETSC_MAX_PATH_LEN, &ropts);CHKERRQ(ierr);
769   ierr = PetscMemzero(&ropts_par, PETSC_MAX_PATH_LEN);CHKERRQ(ierr);
770   ierr = PetscMemzero(&ropts_pargh, PETSC_MAX_PATH_LEN);CHKERRQ(ierr);
771   ierr = PetscMemzero(&ropts_dbg, PETSC_MAX_PATH_LEN);CHKERRQ(ierr);
772 
773   /* do parallel read unless using only one processor */
774   if (numproc > 1) {
775     // 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);
776     ierr = PetscSNPrintf(ropts_par, PETSC_MAX_PATH_LEN, "PARALLEL=%s;PARTITION=PARALLEL_PARTITION;PARTITION_DISTRIBUTE;PARALLEL_RESOLVE_SHARED_ENTS;%s", MoabReadModes[mode], (by_rank ? "PARTITION_BY_RANK;" : ""));CHKERRQ(ierr);
777     if (nghost) {
778       ierr = PetscSNPrintf(ropts_pargh, PETSC_MAX_PATH_LEN, "PARALLEL_GHOSTS=%d.0.%d;", dim, nghost);CHKERRQ(ierr);
779     }
780   }
781 
782   if (dbglevel) {
783     if (numproc > 1) {
784       ierr = PetscSNPrintf(ropts_dbg, PETSC_MAX_PATH_LEN, "CPUTIME;DEBUG_IO=%d;DEBUG_PIO=%d;", dbglevel, dbglevel);CHKERRQ(ierr);
785     }
786     else {
787       ierr = PetscSNPrintf(ropts_dbg, PETSC_MAX_PATH_LEN, "CPUTIME;DEBUG_IO=%d;", dbglevel);CHKERRQ(ierr);
788     }
789   }
790 
791   ierr = PetscSNPrintf(ropts, PETSC_MAX_PATH_LEN, "%s%s%s%s%s", ropts_par, (nghost ? ropts_pargh : ""), ropts_dbg, (extra_opts ? extra_opts : ""), (dm_opts ? dm_opts : ""));CHKERRQ(ierr);
792   *read_opts = ropts;
793   PetscFunctionReturn(0);
794 }
795 
796 /*@C
797   DMMoabLoadFromFile - Creates a DM object by loading the mesh from a user specified file.
798 
799   Collective
800 
801   Input Parameters:
802 + comm - The communicator for the DM object
803 . dim - The spatial dimension
804 . filename - The name of the mesh file to be loaded
805 - usrreadopts - The options string to read a MOAB mesh.
806 
807   Reference (Parallel Mesh Initialization: https://www.mcs.anl.gov/~fathom/moab-docs/html/contents.html#fivetwo)
808 
809   Output Parameter:
810 . dm  - The DM object
811 
812   Level: beginner
813 
814 .seealso: DMSetType(), DMCreate(), DMMoabCreateBoxMesh()
815 @*/
816 PetscErrorCode DMMoabLoadFromFile(MPI_Comm comm, PetscInt dim, PetscInt nghost, const char* filename, const char* usrreadopts, DM *dm)
817 {
818   moab::ErrorCode     merr;
819   PetscInt            nprocs;
820   DM_Moab            *dmmoab;
821   moab::Interface    *mbiface;
822 #ifdef MOAB_HAVE_MPI
823   moab::ParallelComm *pcomm;
824 #endif
825   moab::Range         verts, elems;
826   const char         *readopts;
827   PetscErrorCode      ierr;
828 
829   PetscFunctionBegin;
830   PetscValidPointer(dm, 6);
831 
832   /* Create the basic DMMoab object and keep the default parameters created by DM impls */
833   ierr = DMMoabCreateMoab(comm, NULL, NULL, NULL, dm);CHKERRQ(ierr);
834 
835   /* get all the necessary handles from the private DM object */
836   dmmoab = (DM_Moab*)(*dm)->data;
837   mbiface = dmmoab->mbiface;
838 #ifdef MOAB_HAVE_MPI
839   pcomm = dmmoab->pcomm;
840   nprocs = pcomm->size();
841 #else
842   nprocs = 1;
843 #endif
844   /* TODO: Decipher dimension based on the loaded mesh instead of getting from user */
845   dmmoab->dim = dim;
846   dmmoab->nghostrings = nghost;
847   dmmoab->refct = 1;
848 
849   /* create a file set to associate all entities in current mesh */
850   merr = dmmoab->mbiface->create_meshset(moab::MESHSET_SET, dmmoab->fileset);MBERR("Creating file set failed", merr);
851 
852   /* add mesh loading options specific to the DM */
853   ierr = DMMoab_GetReadOptions_Private(dmmoab->partition_by_rank, nprocs, dim, nghost, dmmoab->read_mode,
854                                        dmmoab->rw_dbglevel, dmmoab->extra_read_options, usrreadopts, &readopts);CHKERRQ(ierr);
855 
856   PetscInfo2(*dm, "Reading file %s with options: %s\n", filename, readopts);
857 
858   /* Load the mesh from a file. */
859   if (dmmoab->fileset) {
860     merr = mbiface->load_file(filename, &dmmoab->fileset, readopts);MBERRVM(mbiface, "Reading MOAB file failed.", merr);
861   }
862   else {
863     merr = mbiface->load_file(filename, 0, readopts);MBERRVM(mbiface, "Reading MOAB file failed.", merr);
864   }
865 
866 #ifdef MOAB_HAVE_MPI
867   /* Reassign global IDs on all entities. */
868   /* merr = pcomm->assign_global_ids(dmmoab->fileset, dim, 1, true, true, true);MBERRNM(merr); */
869 #endif
870 
871   /* load the local vertices */
872   merr = mbiface->get_entities_by_type(dmmoab->fileset, moab::MBVERTEX, verts, true);MBERRNM(merr);
873   /* load the local elements */
874   merr = mbiface->get_entities_by_dimension(dmmoab->fileset, dim, elems, true);MBERRNM(merr);
875 
876 #ifdef MOAB_HAVE_MPI
877   /* Everything is set up, now just do a tag exchange to update tags
878      on all of the ghost vertexes */
879   merr = pcomm->exchange_tags(dmmoab->ltog_tag, verts);MBERRV(mbiface, merr);
880   merr = pcomm->exchange_tags(dmmoab->ltog_tag, elems);MBERRV(mbiface, merr);
881   merr = pcomm->collective_sync_partition();MBERR("Collective sync failed", merr);
882 #endif
883 
884   PetscInfo3(*dm, "MOAB file '%s' was successfully loaded. Found %D vertices and %D elements.\n", filename, verts.size(), elems.size());
885   ierr = PetscFree(readopts);CHKERRQ(ierr);
886   PetscFunctionReturn(0);
887 }
888 
889 /*@C
890   DMMoabRenumberMeshEntities - Order and number all entities (vertices->elements) to be contiguously ordered
891   in parallel
892 
893   Collective
894 
895   Input Parameters:
896 . dm  - The DM object
897 
898   Level: advanced
899 
900 .seealso: DMSetUp(), DMCreate()
901 @*/
902 PetscErrorCode DMMoabRenumberMeshEntities(DM dm)
903 {
904   moab::Range         verts;
905 
906   PetscFunctionBegin;
907   PetscValidHeaderSpecific(dm, DM_CLASSID, 1);
908 
909 #ifdef MOAB_HAVE_MPI
910   /* Insert new points */
911   moab::ErrorCode     merr;
912   merr = ((DM_Moab*) dm->data)->pcomm->assign_global_ids(((DM_Moab*) dm->data)->fileset, 3, 0, false, true, false);MBERRNM(merr);
913 #endif
914   PetscFunctionReturn(0);
915 }
916 
917