Date: 2025-03-29T05:58:20+00:00

Actual source code: dmmbutil.cxx

      1: #include <petsc/private/dmmbimpl.h>
      2: #include <petsc/private/vecimpl.h>

      4: #include <petscdmmoab.h>
      5: #include <MBTagConventions.hpp>
      6: #include <moab/ReadUtilIface.hpp>
      7: #include <moab/MergeMesh.hpp>
      8: #include <moab/CN.hpp>

     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;

     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: } DMMoabMeshGeneratorCtx;

     27: static PetscInt DMMoab_SetTensorElementConnectivity_Private(DMMoabMeshGeneratorCtx &genCtx, PetscInt offset, PetscInt corner, std::vector<PetscInt> &subent_conn, moab::EntityHandle *connectivity)
     28: {
     29:   switch (genCtx.dim) {
     30:   case 1:
     31:     subent_conn.resize(2);
     32:     moab::CN::SubEntityVertexIndices(moab::MBEDGE, 1, 0, subent_conn.data());
     33:     connectivity[offset + subent_conn[0]] = corner;
     34:     connectivity[offset + subent_conn[1]] = corner + 1;
     35:     break;
     36:   case 2:
     37:     subent_conn.resize(4);
     38:     moab::CN::SubEntityVertexIndices(moab::MBQUAD, 2, 0, subent_conn.data());
     39:     connectivity[offset + subent_conn[0]] = corner;
     40:     connectivity[offset + subent_conn[1]] = corner + 1;
     41:     connectivity[offset + subent_conn[2]] = corner + 1 + genCtx.ystride;
     42:     connectivity[offset + subent_conn[3]] = corner + genCtx.ystride;
     43:     break;
     44:   case 3:
     45:   default:
     46:     subent_conn.resize(8);
     47:     moab::CN::SubEntityVertexIndices(moab::MBHEX, 3, 0, subent_conn.data());
     48:     connectivity[offset + subent_conn[0]] = corner;
     49:     connectivity[offset + subent_conn[1]] = corner + 1;
     50:     connectivity[offset + subent_conn[2]] = corner + 1 + genCtx.ystride;
     51:     connectivity[offset + subent_conn[3]] = corner + genCtx.ystride;
     52:     connectivity[offset + subent_conn[4]] = corner + genCtx.zstride;
     53:     connectivity[offset + subent_conn[5]] = corner + 1 + genCtx.zstride;
     54:     connectivity[offset + subent_conn[6]] = corner + 1 + genCtx.ystride + genCtx.zstride;
     55:     connectivity[offset + subent_conn[7]] = corner + genCtx.ystride + genCtx.zstride;
     56:     break;
     57:   }
     58:   return subent_conn.size();
     59: }

     61: static PetscInt DMMoab_SetSimplexElementConnectivity_Private(DMMoabMeshGeneratorCtx &genCtx, PetscInt subelem, PetscInt offset, PetscInt corner, std::vector<PetscInt> &subent_conn, moab::EntityHandle *connectivity)
     62: {
     63:   PetscInt       A, B, C, D, E, F, G, H, M;
     64:   const PetscInt trigen_opts = 1; /* 1 - Aligned diagonally to right, 2 - Aligned diagonally to left, 3 - 4 elements per quad */
     65:   A                          = corner;
     66:   B                          = corner + 1;
     67:   switch (genCtx.dim) {
     68:   case 1:
     69:     subent_conn.resize(2); /* only linear EDGE supported now */
     70:     moab::CN::SubEntityVertexIndices(moab::MBEDGE, 1, 0, subent_conn.data());
     71:     connectivity[offset + subent_conn[0]] = A;
     72:     connectivity[offset + subent_conn[1]] = B;
     73:     break;
     74:   case 2:
     75:     C = corner + 1 + genCtx.ystride;
     76:     D = corner + genCtx.ystride;
     77:     M = corner + 0.5;      /* technically -- need to modify vertex generation */
     78:     subent_conn.resize(3); /* only linear TRI supported */
     79:     moab::CN::SubEntityVertexIndices(moab::MBTRI, 2, 0, subent_conn.data());
     80:     if (trigen_opts == 1) {
     81:       if (subelem) { /* 0 1 2 of a QUAD */
     82:         connectivity[offset + subent_conn[0]] = B;
     83:         connectivity[offset + subent_conn[1]] = C;
     84:         connectivity[offset + subent_conn[2]] = A;
     85:       } else { /* 2 3 0 of a QUAD */
     86:         connectivity[offset + subent_conn[0]] = D;
     87:         connectivity[offset + subent_conn[1]] = A;
     88:         connectivity[offset + subent_conn[2]] = C;
     89:       }
     90:     } else if (trigen_opts == 2) {
     91:       if (subelem) { /* 0 1 2 of a QUAD */
     92:         connectivity[offset + subent_conn[0]] = A;
     93:         connectivity[offset + subent_conn[1]] = B;
     94:         connectivity[offset + subent_conn[2]] = D;
     95:       } else { /* 2 3 0 of a QUAD */
     96:         connectivity[offset + subent_conn[0]] = C;
     97:         connectivity[offset + subent_conn[1]] = D;
     98:         connectivity[offset + subent_conn[2]] = B;
     99:       }
    100:     } else {
    101:       switch (subelem) { /* 0 1 2 of a QUAD */
    102:       case 0:
    103:         connectivity[offset + subent_conn[0]] = A;
    104:         connectivity[offset + subent_conn[1]] = B;
    105:         connectivity[offset + subent_conn[2]] = M;
    106:         break;
    107:       case 1:
    108:         connectivity[offset + subent_conn[0]] = B;
    109:         connectivity[offset + subent_conn[1]] = C;
    110:         connectivity[offset + subent_conn[2]] = M;
    111:         break;
    112:       case 2:
    113:         connectivity[offset + subent_conn[0]] = C;
    114:         connectivity[offset + subent_conn[1]] = D;
    115:         connectivity[offset + subent_conn[2]] = M;
    116:         break;
    117:       case 3:
    118:         connectivity[offset + subent_conn[0]] = D;
    119:         connectivity[offset + subent_conn[1]] = A;
    120:         connectivity[offset + subent_conn[2]] = M;
    121:         break;
    122:       }
    123:     }
    124:     break;
    125:   case 3:
    126:   default:
    127:     C = corner + 1 + genCtx.ystride;
    128:     D = corner + genCtx.ystride;
    129:     E = corner + genCtx.zstride;
    130:     F = corner + 1 + genCtx.zstride;
    131:     G = corner + 1 + genCtx.ystride + genCtx.zstride;
    132:     H = corner + genCtx.ystride + genCtx.zstride;
    133:     subent_conn.resize(4); /* only linear TET supported */
    134:     moab::CN::SubEntityVertexIndices(moab::MBTET, 3, 0, subent_conn.data());
    135:     switch (subelem) {
    136:     case 0: /* 4 3 7 6 of a HEX */
    137:       connectivity[offset + subent_conn[0]] = E;
    138:       connectivity[offset + subent_conn[1]] = D;
    139:       connectivity[offset + subent_conn[2]] = H;
    140:       connectivity[offset + subent_conn[3]] = G;
    141:       break;
    142:     case 1: /* 0 1 2 5 of a HEX */
    143:       connectivity[offset + subent_conn[0]] = A;
    144:       connectivity[offset + subent_conn[1]] = B;
    145:       connectivity[offset + subent_conn[2]] = C;
    146:       connectivity[offset + subent_conn[3]] = F;
    147:       break;
    148:     case 2: /* 0 3 4 5 of a HEX */
    149:       connectivity[offset + subent_conn[0]] = A;
    150:       connectivity[offset + subent_conn[1]] = D;
    151:       connectivity[offset + subent_conn[2]] = E;
    152:       connectivity[offset + subent_conn[3]] = F;
    153:       break;
    154:     case 3: /* 2 6 3 5 of a HEX */
    155:       connectivity[offset + subent_conn[0]] = C;
    156:       connectivity[offset + subent_conn[1]] = G;
    157:       connectivity[offset + subent_conn[2]] = D;
    158:       connectivity[offset + subent_conn[3]] = F;
    159:       break;
    160:     case 4: /* 0 2 3 5 of a HEX */
    161:       connectivity[offset + subent_conn[0]] = A;
    162:       connectivity[offset + subent_conn[1]] = C;
    163:       connectivity[offset + subent_conn[2]] = D;
    164:       connectivity[offset + subent_conn[3]] = F;
    165:       break;
    166:     case 5: /* 3 6 4 5 of a HEX */
    167:       connectivity[offset + subent_conn[0]] = D;
    168:       connectivity[offset + subent_conn[1]] = G;
    169:       connectivity[offset + subent_conn[2]] = E;
    170:       connectivity[offset + subent_conn[3]] = F;
    171:       break;
    172:     }
    173:     break;
    174:   }
    175:   return subent_conn.size();
    176: }

    178: static std::pair<PetscInt, PetscInt> DMMoab_SetElementConnectivity_Private(DMMoabMeshGeneratorCtx &genCtx, PetscInt offset, PetscInt corner, moab::EntityHandle *connectivity)
    179: {
    180:   PetscInt              vcount                  = 0;
    181:   PetscInt              simplices_per_tensor[4] = {0, 1, 2, 6};
    182:   std::vector<PetscInt> subent_conn; /* only linear edge, tri, tet supported now */
    183:   subent_conn.reserve(27);
    184:   PetscInt m, subelem;
    185:   if (genCtx.simplex) {
    186:     subelem = simplices_per_tensor[genCtx.dim];
    187:     for (m = 0; m < subelem; m++) {
    188:       vcount = DMMoab_SetSimplexElementConnectivity_Private(genCtx, m, offset, corner, subent_conn, connectivity);
    189:       offset += vcount;
    190:     }
    191:   } else {
    192:     subelem = 1;
    193:     vcount  = DMMoab_SetTensorElementConnectivity_Private(genCtx, offset, corner, subent_conn, connectivity);
    194:   }
    195:   return std::pair<PetscInt, PetscInt>(vcount * subelem, subelem);
    196: }

    198: static PetscErrorCode DMMoab_GenerateVertices_Private(moab::Interface *mbImpl, moab::ReadUtilIface *iface, DMMoabMeshGeneratorCtx &genCtx, PetscInt m, PetscInt n, PetscInt k, PetscInt a, PetscInt b, PetscInt c, moab::Tag &global_id_tag, moab::EntityHandle &startv, moab::Range &uverts)
    199: {
    200:   PetscInt                 x, y, z, ix, nnodes;
    201:   PetscInt                 ii, jj, kk;
    202:   std::vector<PetscReal *> arrays;
    203:   PetscInt                *gids;
    204:   moab::ErrorCode          merr;

    206:   PetscFunctionBegin;
    207:   /* we will generate (q*block+1)^3 vertices, and block^3 hexas; q is 1 for linear, 2 for quadratic
    208:    * the global id of the vertices will come from m, n, k, a, b, c
    209:    * x will vary from  m*A*q*block + a*q*block to m*A*q*block+(a+1)*q*block etc.
    210:    */
    211:   nnodes = genCtx.blockSizeVertexXYZ[0] * (genCtx.dim > 1 ? genCtx.blockSizeVertexXYZ[1] * (genCtx.dim > 2 ? genCtx.blockSizeVertexXYZ[2] : 1) : 1);
    212:   PetscCall(PetscMalloc1(nnodes, &gids));

    214:   merr = iface->get_node_coords(3, nnodes, 0, startv, arrays);
    215:   MBERR("Can't get node coords.", merr);

    217:   /* will start with the lower corner: */
    218:   /* x = ( m * genCtx.A + a) * genCtx.q * genCtx.blockSizeElementXYZ[0]; */
    219:   /* y = ( n * genCtx.B + b) * genCtx.q * genCtx.blockSizeElementXYZ[1]; */
    220:   /* z = ( k * genCtx.C + c) * genCtx.q * genCtx.blockSizeElementXYZ[2]; */

    222:   x = (m * genCtx.A + a) * genCtx.q;
    223:   y = (n * genCtx.B + b) * genCtx.q;
    224:   z = (k * genCtx.C + c) * genCtx.q;
    225:   PetscCall(PetscInfo(NULL, "Starting offset for coordinates := %" PetscInt_FMT ", %" PetscInt_FMT ", %" PetscInt_FMT "\n", x, y, z));
    226:   ix = 0;
    227:   moab::Range verts(startv, startv + nnodes - 1);
    228:   for (kk = 0; kk < (genCtx.dim > 2 ? genCtx.blockSizeVertexXYZ[2] : 1); kk++) {
    229:     for (jj = 0; jj < (genCtx.dim > 1 ? genCtx.blockSizeVertexXYZ[1] : 1); jj++) {
    230:       for (ii = 0; ii < genCtx.blockSizeVertexXYZ[0]; ii++, ix++) {
    231:         /* set coordinates for the vertices */
    232:         arrays[0][ix] = (x + ii) * genCtx.dx + genCtx.xyzbounds[0];
    233:         arrays[1][ix] = (y + jj) * genCtx.dy + genCtx.xyzbounds[2];
    234:         arrays[2][ix] = (z + kk) * genCtx.dz + genCtx.xyzbounds[4];
    235:         PetscCall(PetscInfo(NULL, "Creating vertex with coordinates := %f, %f, %f\n", arrays[0][ix], arrays[1][ix], arrays[2][ix]));

    237:         /* If we want to set some tags on the vertices -> use the following entity handle definition:
    238:            moab::EntityHandle v = startv + ix;
    239:         */
    240:         /* compute the global ID for vertex */
    241:         gids[ix] = 1 + (x + ii) + (y + jj) * genCtx.NX + (z + kk) * (genCtx.NX * genCtx.NY);
    242:       }
    243:     }
    244:   }
    245:   /* set global ID data on vertices */
    246:   mbImpl->tag_set_data(global_id_tag, verts, &gids[0]);
    247:   verts.swap(uverts);
    248:   PetscCall(PetscFree(gids));
    249:   PetscFunctionReturn(PETSC_SUCCESS);
    250: }

    252: static PetscErrorCode DMMoab_GenerateElements_Private(moab::Interface *mbImpl, moab::ReadUtilIface *iface, DMMoabMeshGeneratorCtx &genCtx, PetscInt m, PetscInt n, PetscInt k, PetscInt a, PetscInt b, PetscInt c, moab::Tag &global_id_tag, moab::EntityHandle startv, moab::Range &cells)
    253: {
    254:   moab::ErrorCode     merr;
    255:   PetscInt            ix, ie, xe, ye, ze;
    256:   PetscInt            ii, jj, kk, nvperelem;
    257:   PetscInt            simplices_per_tensor[4] = {0, 1, 2, 6};
    258:   PetscInt            ntensorelems            = genCtx.blockSizeElementXYZ[0] * (genCtx.dim > 1 ? genCtx.blockSizeElementXYZ[1] * (genCtx.dim > 2 ? genCtx.blockSizeElementXYZ[2] : 1) : 1); /*pow(genCtx.blockSizeElement,genCtx.dim);*/
    259:   PetscInt            nelems                  = ntensorelems;
    260:   moab::EntityHandle  starte; /* connectivity */
    261:   moab::EntityHandle *conn;

    263:   PetscFunctionBegin;
    264:   switch (genCtx.dim) {
    265:   case 1:
    266:     nvperelem = 2;
    267:     merr      = iface->get_element_connect(nelems, 2, moab::MBEDGE, 0, starte, conn);
    268:     MBERR("Can't get EDGE2 element connectivity.", merr);
    269:     break;
    270:   case 2:
    271:     if (genCtx.simplex) {
    272:       nvperelem = 3;
    273:       nelems    = ntensorelems * simplices_per_tensor[genCtx.dim];
    274:       merr      = iface->get_element_connect(nelems, 3, moab::MBTRI, 0, starte, conn);
    275:       MBERR("Can't get TRI3 element connectivity.", merr);
    276:     } else {
    277:       nvperelem = 4;
    278:       merr      = iface->get_element_connect(nelems, 4, moab::MBQUAD, 0, starte, conn);
    279:       MBERR("Can't get QUAD4 element connectivity.", merr);
    280:     }
    281:     break;
    282:   case 3:
    283:   default:
    284:     if (genCtx.simplex) {
    285:       nvperelem = 4;
    286:       nelems    = ntensorelems * simplices_per_tensor[genCtx.dim];
    287:       merr      = iface->get_element_connect(nelems, 4, moab::MBTET, 0, starte, conn);
    288:       MBERR("Can't get TET4 element connectivity.", merr);
    289:     } else {
    290:       nvperelem = 8;
    291:       merr      = iface->get_element_connect(nelems, 8, moab::MBHEX, 0, starte, conn);
    292:       MBERR("Can't get HEX8 element connectivity.", merr);
    293:     }
    294:     break;
    295:   }

    297:   ix = ie = 0; /* index now in the elements, for global ids */

    299:   /* create a temporary range to store local element handles */
    300:   moab::Range           tmp(starte, starte + nelems - 1);
    301:   std::vector<PetscInt> gids(nelems);

    303:   /* identify the elements at the lower corner, for their global ids */
    304:   xe = m * genCtx.A * genCtx.blockSizeElementXYZ[0] + a * genCtx.blockSizeElementXYZ[0];
    305:   ye = (genCtx.dim > 1 ? n * genCtx.B * genCtx.blockSizeElementXYZ[1] + b * genCtx.blockSizeElementXYZ[1] : 0);
    306:   ze = (genCtx.dim > 2 ? k * genCtx.C * genCtx.blockSizeElementXYZ[2] + c * genCtx.blockSizeElementXYZ[2] : 0);

    308:   /* create owned elements requested by genCtx */
    309:   for (kk = 0; kk < (genCtx.dim > 2 ? genCtx.blockSizeElementXYZ[2] : 1); kk++) {
    310:     for (jj = 0; jj < (genCtx.dim > 1 ? genCtx.blockSizeElementXYZ[1] : 1); jj++) {
    311:       for (ii = 0; ii < genCtx.blockSizeElementXYZ[0]; ii++) {
    312:         moab::EntityHandle corner = startv + genCtx.q * ii + genCtx.q * jj * genCtx.ystride + genCtx.q * kk * genCtx.zstride;

    314:         std::pair<PetscInt, PetscInt> entoffset = DMMoab_SetElementConnectivity_Private(genCtx, ix, corner, conn);

    316:         for (PetscInt j = 0; j < entoffset.second; j++) {
    317:           /* The entity handle for the particular element -> if we want to set some tags is
    318:              moab::EntityHandle eh = starte + ie + j;
    319:           */
    320:           gids[ie + j] = 1 + ((xe + ii) + (ye + jj) * genCtx.nex + (ze + kk) * (genCtx.nex * genCtx.ney));
    321:           /* gids[ie+j] = ie + j + ((xe + ii) + (ye + jj) * genCtx.nex + (ze + kk) * (genCtx.nex * genCtx.ney)); */
    322:           /* gids[ie+j] = 1 + ie; */
    323:           /* ie++; */
    324:         }

    326:         ix += entoffset.first;
    327:         ie += entoffset.second;
    328:       }
    329:     }
    330:   }
    331:   if (genCtx.adjEnts) { /* we need to update adjacencies now, because some elements are new */
    332:     merr = iface->update_adjacencies(starte, nelems, nvperelem, conn);
    333:     MBERR("Can't update adjacencies", merr);
    334:   }
    335:   tmp.swap(cells);
    336:   merr = mbImpl->tag_set_data(global_id_tag, cells, &gids[0]);
    337:   MBERR("Can't set global ids to elements.", merr);
    338:   PetscFunctionReturn(PETSC_SUCCESS);
    339: }

    341: static PetscErrorCode DMMBUtil_InitializeOptions(DMMoabMeshGeneratorCtx &genCtx, PetscInt dim, PetscBool simplex, PetscInt rank, PetscInt nprocs, const PetscReal *bounds, PetscInt nelems)
    342: {
    343:   PetscFunctionBegin;
    344:   /* Initialize all genCtx data */
    345:   genCtx.dim            = dim;
    346:   genCtx.simplex        = simplex;
    347:   genCtx.newMergeMethod = genCtx.keep_skins = genCtx.adjEnts = true;
    348:   /* determine other global quantities for the mesh used for nodes increments */
    349:   genCtx.q        = 1;
    350:   genCtx.fraction = genCtx.remainder = genCtx.cumfraction = 0;

    352:   if (!genCtx.usrxyzgrid) { /* not overridden by genCtx - assume nele equally and that genCtx wants a uniform cube mesh */

    354:     genCtx.fraction    = nelems / nprocs; /* partition only by the largest dimension */
    355:     genCtx.remainder   = nelems % nprocs; /* remainder after partition which gets evenly distributed by round-robin */
    356:     genCtx.cumfraction = (rank > 0 ? (genCtx.fraction) * (rank) + (rank - 1 < genCtx.remainder ? rank : genCtx.remainder) : 0);
    357:     if (rank < genCtx.remainder) /* This process gets "fraction+1" elements */
    358:       genCtx.fraction++;

    360:     PetscCall(PetscInfo(NULL, "Fraction = %" PetscInt_FMT ", Remainder = %" PetscInt_FMT ", Cumulative fraction = %" PetscInt_FMT "\n", genCtx.fraction, genCtx.remainder, genCtx.cumfraction));
    361:     switch (genCtx.dim) {
    362:     case 1:
    363:       genCtx.blockSizeElementXYZ[0] = genCtx.fraction;
    364:       genCtx.blockSizeElementXYZ[1] = 1;
    365:       genCtx.blockSizeElementXYZ[2] = 1;
    366:       break;
    367:     case 2:
    368:       genCtx.blockSizeElementXYZ[0] = nelems;
    369:       genCtx.blockSizeElementXYZ[1] = genCtx.fraction;
    370:       genCtx.blockSizeElementXYZ[2] = 1;
    371:       break;
    372:     case 3:
    373:     default:
    374:       genCtx.blockSizeElementXYZ[0] = nelems;
    375:       genCtx.blockSizeElementXYZ[1] = nelems;
    376:       genCtx.blockSizeElementXYZ[2] = genCtx.fraction;
    377:       break;
    378:     }
    379:   }

    381:   /* partition only by the largest dimension */
    382:   /* Total number of local elements := genCtx.blockSizeElementXYZ[0]*(genCtx.dim>1? genCtx.blockSizeElementXYZ[1]*(genCtx.dim>2 ? genCtx.blockSizeElementXYZ[2]:1) :1); */
    383:   if (bounds) {
    384:     for (PetscInt i = 0; i < 6; i++) genCtx.xyzbounds[i] = bounds[i];
    385:   } else {
    386:     genCtx.xyzbounds[0] = genCtx.xyzbounds[2] = genCtx.xyzbounds[4] = 0.0;
    387:     genCtx.xyzbounds[1] = genCtx.xyzbounds[3] = genCtx.xyzbounds[5] = 1.0;
    388:   }

    390:   if (!genCtx.usrprocgrid) {
    391:     switch (genCtx.dim) {
    392:     case 1:
    393:       genCtx.M = nprocs;
    394:       genCtx.N = genCtx.K = 1;
    395:       break;
    396:     case 2:
    397:       genCtx.N = nprocs;
    398:       genCtx.M = genCtx.K = 1;
    399:       break;
    400:     default:
    401:       genCtx.K = nprocs;
    402:       genCtx.M = genCtx.N = 1;
    403:       break;
    404:     }
    405:   }

    407:   if (!genCtx.usrrefgrid) genCtx.A = genCtx.B = genCtx.C = 1;

    409:   /* more default values */
    410:   genCtx.nex = genCtx.ney = genCtx.nez = 0;
    411:   genCtx.xstride = genCtx.ystride = genCtx.zstride = 0;
    412:   genCtx.NX = genCtx.NY = genCtx.NZ = 0;
    413:   genCtx.nex = genCtx.ney = genCtx.nez = 0;
    414:   genCtx.blockSizeVertexXYZ[0] = genCtx.blockSizeVertexXYZ[1] = genCtx.blockSizeVertexXYZ[2] = 1;

    416:   switch (genCtx.dim) {
    417:   case 3:
    418:     genCtx.blockSizeVertexXYZ[0] = genCtx.q * genCtx.blockSizeElementXYZ[0] + 1;
    419:     genCtx.blockSizeVertexXYZ[1] = genCtx.q * genCtx.blockSizeElementXYZ[1] + 1;
    420:     genCtx.blockSizeVertexXYZ[2] = genCtx.q * genCtx.blockSizeElementXYZ[2] + 1;

    422:     genCtx.nex     = genCtx.M * genCtx.A * genCtx.blockSizeElementXYZ[0];               /* number of elements in x direction, used for global id on element */
    423:     genCtx.dx      = (genCtx.xyzbounds[1] - genCtx.xyzbounds[0]) / (nelems * genCtx.q); /* distance between 2 nodes in x direction */
    424:     genCtx.NX      = (genCtx.q * genCtx.nex + 1);
    425:     genCtx.xstride = 1;
    426:     genCtx.ney     = genCtx.N * genCtx.B * genCtx.blockSizeElementXYZ[1];               /* number of elements in y direction  .... */
    427:     genCtx.dy      = (genCtx.xyzbounds[3] - genCtx.xyzbounds[2]) / (nelems * genCtx.q); /* distance between 2 nodes in y direction */
    428:     genCtx.NY      = (genCtx.q * genCtx.ney + 1);
    429:     genCtx.ystride = genCtx.blockSizeVertexXYZ[0];
    430:     genCtx.nez     = genCtx.K * genCtx.C * genCtx.blockSizeElementXYZ[2];               /* number of elements in z direction  .... */
    431:     genCtx.dz      = (genCtx.xyzbounds[5] - genCtx.xyzbounds[4]) / (nelems * genCtx.q); /* distance between 2 nodes in z direction */
    432:     genCtx.NZ      = (genCtx.q * genCtx.nez + 1);
    433:     genCtx.zstride = genCtx.blockSizeVertexXYZ[0] * genCtx.blockSizeVertexXYZ[1];
    434:     break;
    435:   case 2:
    436:     genCtx.blockSizeVertexXYZ[0] = genCtx.q * genCtx.blockSizeElementXYZ[0] + 1;
    437:     genCtx.blockSizeVertexXYZ[1] = genCtx.q * genCtx.blockSizeElementXYZ[1] + 1;
    438:     genCtx.blockSizeVertexXYZ[2] = 0;

    440:     genCtx.nex     = genCtx.M * genCtx.A * genCtx.blockSizeElementXYZ[0];                   /* number of elements in x direction, used for global id on element */
    441:     genCtx.dx      = (genCtx.xyzbounds[1] - genCtx.xyzbounds[0]) / (genCtx.nex * genCtx.q); /* distance between 2 nodes in x direction */
    442:     genCtx.NX      = (genCtx.q * genCtx.nex + 1);
    443:     genCtx.xstride = 1;
    444:     genCtx.ney     = genCtx.N * genCtx.B * genCtx.blockSizeElementXYZ[1];               /* number of elements in y direction  .... */
    445:     genCtx.dy      = (genCtx.xyzbounds[3] - genCtx.xyzbounds[2]) / (nelems * genCtx.q); /* distance between 2 nodes in y direction */
    446:     genCtx.NY      = (genCtx.q * genCtx.ney + 1);
    447:     genCtx.ystride = genCtx.blockSizeVertexXYZ[0];
    448:     break;
    449:   case 1:
    450:     genCtx.blockSizeVertexXYZ[1] = genCtx.blockSizeVertexXYZ[2] = 0;
    451:     genCtx.blockSizeVertexXYZ[0]                                = genCtx.q * genCtx.blockSizeElementXYZ[0] + 1;

    453:     genCtx.nex     = genCtx.M * genCtx.A * genCtx.blockSizeElementXYZ[0];               /* number of elements in x direction, used for global id on element */
    454:     genCtx.dx      = (genCtx.xyzbounds[1] - genCtx.xyzbounds[0]) / (nelems * genCtx.q); /* distance between 2 nodes in x direction */
    455:     genCtx.NX      = (genCtx.q * genCtx.nex + 1);
    456:     genCtx.xstride = 1;
    457:     break;
    458:   }

    460:   /* Lets check for some valid input */
    461:   PetscCheck(genCtx.dim >= 1 && genCtx.dim <= 3, PETSC_COMM_WORLD, PETSC_ERR_ARG_OUTOFRANGE, "Invalid topological dimension specified: %" PetscInt_FMT ".", genCtx.dim);
    462:   PetscCheck(genCtx.M * genCtx.N * genCtx.K == nprocs, PETSC_COMM_WORLD, PETSC_ERR_ARG_OUTOFRANGE, "Invalid [m, n, k] data: %" PetscInt_FMT ", %" PetscInt_FMT ", %" PetscInt_FMT ". Product must be equal to global size = %" PetscInt_FMT ".", genCtx.M,
    463:              genCtx.N, genCtx.K, nprocs);
    464:   /* validate the bounds data */
    465:   PetscCheck(genCtx.xyzbounds[0] < genCtx.xyzbounds[1], PETSC_COMM_WORLD, PETSC_ERR_ARG_OUTOFRANGE, "X-dim: Left boundary cannot be greater than right. [%G >= %G]", genCtx.xyzbounds[0], genCtx.xyzbounds[1]);
    466:   PetscCheck(genCtx.dim <= 1 || genCtx.xyzbounds[2] < genCtx.xyzbounds[3], PETSC_COMM_WORLD, PETSC_ERR_ARG_OUTOFRANGE, "Y-dim: Left boundary cannot be greater than right. [%G >= %G]", genCtx.xyzbounds[2], genCtx.xyzbounds[3]);
    467:   PetscCheck(genCtx.dim <= 2 || genCtx.xyzbounds[4] < genCtx.xyzbounds[5], PETSC_COMM_WORLD, PETSC_ERR_ARG_OUTOFRANGE, "Z-dim: Left boundary cannot be greater than right. [%G >= %G]", genCtx.xyzbounds[4], genCtx.xyzbounds[5]);

    469:   PetscCall(PetscInfo(NULL, "Local elements:= %" PetscInt_FMT ", %" PetscInt_FMT ", %" PetscInt_FMT "\n", genCtx.blockSizeElementXYZ[0], genCtx.blockSizeElementXYZ[1], genCtx.blockSizeElementXYZ[2]));
    470:   PetscCall(PetscInfo(NULL, "Local vertices:= %" PetscInt_FMT ", %" PetscInt_FMT ", %" PetscInt_FMT "\n", genCtx.blockSizeVertexXYZ[0], genCtx.blockSizeVertexXYZ[1], genCtx.blockSizeVertexXYZ[2]));
    471:   PetscCall(PetscInfo(NULL, "Local blocks/processors := %" PetscInt_FMT ", %" PetscInt_FMT ", %" PetscInt_FMT "\n", genCtx.A, genCtx.B, genCtx.C));
    472:   PetscCall(PetscInfo(NULL, "Local processors := %" PetscInt_FMT ", %" PetscInt_FMT ", %" PetscInt_FMT "\n", genCtx.M, genCtx.N, genCtx.K));
    473:   PetscCall(PetscInfo(NULL, "Local nexyz:= %" PetscInt_FMT ", %" PetscInt_FMT ", %" PetscInt_FMT "\n", genCtx.nex, genCtx.ney, genCtx.nez));
    474:   PetscCall(PetscInfo(NULL, "Local delxyz:= %g, %g, %g\n", genCtx.dx, genCtx.dy, genCtx.dz));
    475:   PetscCall(PetscInfo(NULL, "Local strides:= %" PetscInt_FMT ", %" PetscInt_FMT ", %" PetscInt_FMT "\n", genCtx.xstride, genCtx.ystride, genCtx.zstride));
    476:   PetscFunctionReturn(PETSC_SUCCESS);
    477: }

    479: /*@C
    480:   DMMoabCreateBoxMesh - Creates a mesh on the tensor product (box) of intervals with genCtx specified bounds.

    482:   Collective

    484:   Input Parameters:
    485: + comm       - The communicator for the DM object
    486: . dim        - The spatial dimension
    487: . useSimplex - use a simplex mesh
    488: . 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
    489: . nele       - The number of discrete elements in each direction
    490: - nghost     - The number of ghosted layers needed in the partitioned mesh

    492:   Output Parameter:
    493: . dm - The `DM` object

    495:   Level: beginner

    497: .seealso: `DMSetType()`, `DMCreate()`, `DMMoabLoadFromFile()`
    498: @*/
    499: PetscErrorCode DMMoabCreateBoxMesh(MPI_Comm comm, PetscInt dim, PetscBool useSimplex, const PetscReal *bounds, PetscInt nele, PetscInt nghost, DM *dm)
    500: {
    501:   moab::ErrorCode  merr;
    502:   PetscInt         a, b, c, n, global_size, global_rank;
    503:   DM_Moab         *dmmoab;
    504:   moab::Interface *mbImpl;
    505: #ifdef MOAB_HAVE_MPI
    506:   moab::ParallelComm *pcomm;
    507: #endif
    508:   moab::ReadUtilIface   *readMeshIface;
    509:   moab::Range            verts, cells, edges, faces, adj, dim3, dim2;
    510:   DMMoabMeshGeneratorCtx genCtx;
    511:   const PetscInt         npts = nele + 1; /* Number of points in every dimension */

    513:   moab::Tag          global_id_tag, part_tag, geom_tag, mat_tag, dir_tag, neu_tag;
    514:   moab::Range        ownedvtx, ownedelms, localvtxs, localelms;
    515:   moab::EntityHandle regionset;
    516:   PetscInt           ml = 0, nl = 0, kl = 0;

    518:   PetscFunctionBegin;
    519:   PetscCheck(dim >= 1 && dim <= 3, PETSC_COMM_WORLD, PETSC_ERR_ARG_OUTOFRANGE, "Invalid dimension argument for mesh: dim=[1,3].");

    521:   PetscCall(PetscLogEventRegister("GenerateMesh", DM_CLASSID, &genCtx.generateMesh));
    522:   PetscCall(PetscLogEventRegister("AddVertices", DM_CLASSID, &genCtx.generateVertices));
    523:   PetscCall(PetscLogEventRegister("AddElements", DM_CLASSID, &genCtx.generateElements));
    524:   PetscCall(PetscLogEventRegister("ParResolve", DM_CLASSID, &genCtx.parResolve));
    525:   PetscCall(PetscLogEventBegin(genCtx.generateMesh, 0, 0, 0, 0));
    526:   PetscCallMPI(MPI_Comm_size(comm, &global_size));
    527:   /* total number of vertices in all dimensions */
    528:   n = pow(npts, dim);

    530:   /* do some error checking */
    531:   PetscCheck(n >= 2, PETSC_COMM_WORLD, PETSC_ERR_ARG_OUTOFRANGE, "Number of points must be >= 2.");
    532:   PetscCheck(global_size <= n, PETSC_COMM_WORLD, PETSC_ERR_ARG_OUTOFRANGE, "Number of processors must be less than or equal to number of elements.");
    533:   PetscCheck(nghost >= 0, PETSC_COMM_WORLD, PETSC_ERR_ARG_OUTOFRANGE, "Number of ghost layers cannot be negative.");

    535:   /* Create the basic DMMoab object and keep the default parameters created by DM impls */
    536:   PetscCall(DMMoabCreateMoab(comm, NULL, NULL, NULL, dm));

    538:   /* get all the necessary handles from the private DM object */
    539:   dmmoab = (DM_Moab *)(*dm)->data;
    540:   mbImpl = dmmoab->mbiface;
    541: #ifdef MOAB_HAVE_MPI
    542:   pcomm       = dmmoab->pcomm;
    543:   global_rank = pcomm->rank();
    544: #else
    545:   global_rank = 0;
    546:   global_size = 1;
    547: #endif
    548:   global_id_tag       = dmmoab->ltog_tag;
    549:   dmmoab->dim         = dim;
    550:   dmmoab->nghostrings = nghost;
    551:   dmmoab->refct       = 1;

    553:   /* create a file set to associate all entities in current mesh */
    554:   merr = mbImpl->create_meshset(moab::MESHSET_SET, dmmoab->fileset);
    555:   MBERR("Creating file set failed", merr);

    557:   /* No errors yet; proceed with building the mesh */
    558:   merr = mbImpl->query_interface(readMeshIface);
    559:   MBERRNM(merr);

    561:   genCtx.M = genCtx.N = genCtx.K = 1;
    562:   genCtx.A = genCtx.B = genCtx.C = 1;
    563:   genCtx.blockSizeElementXYZ[0]  = 0;
    564:   genCtx.blockSizeElementXYZ[1]  = 0;
    565:   genCtx.blockSizeElementXYZ[2]  = 0;

    567:   PetscOptionsBegin(comm, "", "DMMoab Creation Options", "DMMOAB");
    568:   /* Handle DMMoab spatial resolution */
    569:   PetscCall(PetscOptionsInt("-dmb_grid_x", "Number of grid points in x direction", "DMMoabSetSizes", genCtx.blockSizeElementXYZ[0], &genCtx.blockSizeElementXYZ[0], &genCtx.usrxyzgrid));
    570:   if (dim > 1) PetscCall(PetscOptionsInt("-dmb_grid_y", "Number of grid points in y direction", "DMMoabSetSizes", genCtx.blockSizeElementXYZ[1], &genCtx.blockSizeElementXYZ[1], &genCtx.usrxyzgrid));
    571:   if (dim > 2) PetscCall(PetscOptionsInt("-dmb_grid_z", "Number of grid points in z direction", "DMMoabSetSizes", genCtx.blockSizeElementXYZ[2], &genCtx.blockSizeElementXYZ[2], &genCtx.usrxyzgrid));

    573:   /* Handle DMMoab parallel distribution */
    574:   PetscCall(PetscOptionsInt("-dmb_processors_x", "Number of processors in x direction", "DMMoabSetNumProcs", genCtx.M, &genCtx.M, &genCtx.usrprocgrid));
    575:   if (dim > 1) PetscCall(PetscOptionsInt("-dmb_processors_y", "Number of processors in y direction", "DMMoabSetNumProcs", genCtx.N, &genCtx.N, &genCtx.usrprocgrid));
    576:   if (dim > 2) PetscCall(PetscOptionsInt("-dmb_processors_z", "Number of processors in z direction", "DMMoabSetNumProcs", genCtx.K, &genCtx.K, &genCtx.usrprocgrid));

    578:   /* Handle DMMoab block refinement */
    579:   PetscCall(PetscOptionsInt("-dmb_refine_x", "Number of refinement blocks in x direction", "DMMoabSetRefinement", genCtx.A, &genCtx.A, &genCtx.usrrefgrid));
    580:   if (dim > 1) PetscCall(PetscOptionsInt("-dmb_refine_y", "Number of refinement blocks in y direction", "DMMoabSetRefinement", genCtx.B, &genCtx.B, &genCtx.usrrefgrid));
    581:   if (dim > 2) PetscCall(PetscOptionsInt("-dmb_refine_z", "Number of refinement blocks in z direction", "DMMoabSetRefinement", genCtx.C, &genCtx.C, &genCtx.usrrefgrid));
    582:   PetscOptionsEnd();

    584:   PetscCall(DMMBUtil_InitializeOptions(genCtx, dim, useSimplex, global_rank, global_size, bounds, nele));

    586:   //PetscCheck(nele>=nprocs,PETSC_COMM_WORLD,PETSC_ERR_ARG_OUTOFRANGE,"The dimensional discretization size should be greater or equal to number of processors: %" PetscInt_FMT " < %" PetscInt_FMT,nele,nprocs);

    588:   if (genCtx.adjEnts) genCtx.keep_skins = true; /* do not delete anything - consumes more memory */

    590:   /* determine m, n, k for processor rank */
    591:   ml = nl = kl = 0;
    592:   switch (genCtx.dim) {
    593:   case 1:
    594:     ml = (genCtx.cumfraction);
    595:     break;
    596:   case 2:
    597:     nl = (genCtx.cumfraction);
    598:     break;
    599:   default:
    600:     kl = (genCtx.cumfraction) / genCtx.q / genCtx.blockSizeElementXYZ[2] / genCtx.C; //genCtx.K
    601:     break;
    602:   }

    604:   /*
    605:    * so there are a total of M * A * blockSizeElement elements in x direction (so M * A * blockSizeElement + 1 verts in x direction)
    606:    * so there are a total of N * B * blockSizeElement elements in y direction (so N * B * blockSizeElement + 1 verts in y direction)
    607:    * so there are a total of K * C * blockSizeElement elements in z direction (so K * C * blockSizeElement + 1 verts in z direction)

    609:    * there are ( M * A blockSizeElement)      *  ( N * B * blockSizeElement)      * (K * C * blockSizeElement)    hexas
    610:    * there are ( M * A * blockSizeElement + 1) *  ( N * B * blockSizeElement + 1) * (K * C * blockSizeElement + 1) vertices
    611:    * x is the first dimension that varies
    612:    */

    614:   /* generate the block at (a, b, c); it will represent a partition , it will get a partition tag */
    615:   PetscInt dum_id = -1;
    616:   merr            = mbImpl->tag_get_handle("GLOBAL_ID", 1, moab::MB_TYPE_INTEGER, global_id_tag);
    617:   MBERR("Getting Global_ID Tag handle failed", merr);

    619:   merr = mbImpl->tag_get_handle(MATERIAL_SET_TAG_NAME, 1, moab::MB_TYPE_INTEGER, mat_tag);
    620:   MBERR("Getting Material set Tag handle failed", merr);
    621:   merr = mbImpl->tag_get_handle(DIRICHLET_SET_TAG_NAME, 1, moab::MB_TYPE_INTEGER, dir_tag);
    622:   MBERR("Getting Dirichlet set Tag handle failed", merr);
    623:   merr = mbImpl->tag_get_handle(NEUMANN_SET_TAG_NAME, 1, moab::MB_TYPE_INTEGER, neu_tag);
    624:   MBERR("Getting Neumann set Tag handle failed", merr);

    626:   merr = mbImpl->tag_get_handle("PARALLEL_PARTITION", 1, moab::MB_TYPE_INTEGER, part_tag, moab::MB_TAG_CREAT | moab::MB_TAG_SPARSE, &dum_id);
    627:   MBERR("Getting Partition Tag handle failed", merr);

    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);
    631:   MBERRNM(merr);
    632:   merr = mbImpl->create_meshset(moab::MESHSET_SET, regionset);
    633:   MBERRNM(merr);
    634:   PetscCall(PetscLogEventEnd(genCtx.generateMesh, 0, 0, 0, 0));

    636:   for (a = 0; a < (genCtx.dim > 0 ? genCtx.A : genCtx.A); a++) {
    637:     for (b = 0; b < (genCtx.dim > 1 ? genCtx.B : 1); b++) {
    638:       for (c = 0; c < (genCtx.dim > 2 ? genCtx.C : 1); c++) {
    639:         moab::EntityHandle startv;

    641:         PetscCall(PetscLogEventBegin(genCtx.generateVertices, 0, 0, 0, 0));
    642:         PetscCall(DMMoab_GenerateVertices_Private(mbImpl, readMeshIface, genCtx, ml, nl, kl, a, b, c, global_id_tag, startv, verts));
    643:         PetscCall(PetscLogEventEnd(genCtx.generateVertices, 0, 0, 0, 0));

    645:         PetscCall(PetscLogEventBegin(genCtx.generateElements, 0, 0, 0, 0));
    646:         PetscCall(DMMoab_GenerateElements_Private(mbImpl, readMeshIface, genCtx, ml, nl, kl, a, b, c, global_id_tag, startv, cells));
    647:         PetscCall(PetscLogEventEnd(genCtx.generateElements, 0, 0, 0, 0));

    649:         PetscInt part_num = 0;
    650:         switch (genCtx.dim) {
    651:         case 3:
    652:           part_num += (c + kl * genCtx.C) * (genCtx.M * genCtx.A * genCtx.N * genCtx.B);
    653:         case 2:
    654:           part_num += (b + nl * genCtx.B) * (genCtx.M * genCtx.A);
    655:         case 1:
    656:           part_num += (a + ml * genCtx.A);
    657:           break;
    658:         }

    660:         moab::EntityHandle part_set;
    661:         merr = mbImpl->create_meshset(moab::MESHSET_SET, part_set);
    662:         MBERR("Can't create mesh set.", merr);

    664:         merr = mbImpl->add_entities(part_set, verts);
    665:         MBERR("Can't add vertices to set.", merr);
    666:         merr = mbImpl->add_entities(part_set, cells);
    667:         MBERR("Can't add entities to set.", merr);
    668:         merr = mbImpl->add_entities(regionset, cells);
    669:         MBERR("Can't add entities to set.", merr);

    671:         /* if needed, add all edges and faces */
    672:         if (genCtx.adjEnts) {
    673:           if (genCtx.dim > 1) {
    674:             merr = mbImpl->get_adjacencies(cells, 1, true, edges, moab::Interface::UNION);
    675:             MBERR("Can't get edges", merr);
    676:             merr = mbImpl->add_entities(part_set, edges);
    677:             MBERR("Can't add edges to partition set.", merr);
    678:           }
    679:           if (genCtx.dim > 2) {
    680:             merr = mbImpl->get_adjacencies(cells, 2, true, faces, moab::Interface::UNION);
    681:             MBERR("Can't get faces", merr);
    682:             merr = mbImpl->add_entities(part_set, faces);
    683:             MBERR("Can't add faces to partition set.", merr);
    684:           }
    685:           edges.clear();
    686:           faces.clear();
    687:         }
    688:         verts.clear();
    689:         cells.clear();

    691:         merr = mbImpl->tag_set_data(part_tag, &part_set, 1, &part_num);
    692:         MBERR("Can't set part tag on set", merr);
    693:         if (dmmoab->fileset) {
    694:           merr = mbImpl->add_parent_child(dmmoab->fileset, part_set);
    695:           MBERR("Can't add part set to file set.", merr);
    696:           merr = mbImpl->unite_meshset(dmmoab->fileset, part_set);
    697:           MBERRNM(merr);
    698:         }
    699:         merr = mbImpl->add_entities(dmmoab->fileset, &part_set, 1);
    700:         MBERRNM(merr);
    701:       }
    702:     }
    703:   }

    705:   merr = mbImpl->add_parent_child(dmmoab->fileset, regionset);
    706:   MBERRNM(merr);

    708:   /* Only in parallel: resolve shared entities between processors and exchange ghost layers */
    709:   if (global_size > 1) {
    710:     PetscCall(PetscLogEventBegin(genCtx.parResolve, 0, 0, 0, 0));

    712:     merr = mbImpl->get_entities_by_dimension(dmmoab->fileset, genCtx.dim, cells);
    713:     MBERR("Can't get all d-dimensional elements.", merr);
    714:     merr = mbImpl->get_entities_by_dimension(dmmoab->fileset, 0, verts);
    715:     MBERR("Can't get all vertices.", merr);

    717:     if (genCtx.A * genCtx.B * genCtx.C != 1) { //  merge needed
    718:       moab::MergeMesh mm(mbImpl);
    719:       if (genCtx.newMergeMethod) {
    720:         merr = mm.merge_using_integer_tag(verts, global_id_tag);
    721:         MBERR("Can't merge with GLOBAL_ID tag", merr);
    722:       } else {
    723:         merr = mm.merge_entities(cells, 0.0001);
    724:         MBERR("Can't merge with coordinates", merr);
    725:       }
    726:     }

    728: #ifdef MOAB_HAVE_MPI
    729:     /* check the handles */
    730:     merr = pcomm->check_all_shared_handles();
    731:     MBERRV(mbImpl, merr);

    733:     /* resolve the shared entities by exchanging information to adjacent processors */
    734:     merr = pcomm->resolve_shared_ents(dmmoab->fileset, cells, dim, dim - 1, NULL, &global_id_tag);
    735:     MBERRV(mbImpl, merr);
    736:     if (dmmoab->fileset) {
    737:       merr = pcomm->exchange_ghost_cells(dim, 0, nghost, dim, true, false, &dmmoab->fileset);
    738:       MBERRV(mbImpl, merr);
    739:     } else {
    740:       merr = pcomm->exchange_ghost_cells(dim, 0, nghost, dim, true, false);
    741:       MBERRV(mbImpl, merr);
    742:     }

    744:     /* Reassign global IDs on all entities. */
    745:     merr = pcomm->assign_global_ids(dmmoab->fileset, dim, 1, false, true, false);
    746:     MBERRNM(merr);
    747: #endif

    749:     PetscCall(PetscLogEventEnd(genCtx.parResolve, 0, 0, 0, 0));
    750:   }

    752:   if (!genCtx.keep_skins) { // default is to delete the 1- and 2-dimensional entities
    753:     // delete all quads and edges
    754:     moab::Range toDelete;
    755:     if (genCtx.dim > 1) {
    756:       merr = mbImpl->get_entities_by_dimension(dmmoab->fileset, 1, toDelete);
    757:       MBERR("Can't get edges", merr);
    758:     }

    760:     if (genCtx.dim > 2) {
    761:       merr = mbImpl->get_entities_by_dimension(dmmoab->fileset, 2, toDelete);
    762:       MBERR("Can't get faces", merr);
    763:     }

    765: #ifdef MOAB_HAVE_MPI
    766:     merr = dmmoab->pcomm->delete_entities(toDelete);
    767:     MBERR("Can't delete entities", merr);
    768: #endif
    769:   }

    771:   /* set geometric dimension tag for regions */
    772:   merr = mbImpl->tag_set_data(geom_tag, &regionset, 1, &dmmoab->dim);
    773:   MBERRNM(merr);
    774:   /* set default material ID for regions */
    775:   int default_material = 1;
    776:   merr                 = mbImpl->tag_set_data(mat_tag, &regionset, 1, &default_material);
    777:   MBERRNM(merr);
    778:   /*
    779:     int default_dbc = 0;
    780:     merr = mbImpl->tag_set_data(dir_tag, &vertexset, 1, &default_dbc);MBERRNM(merr);
    781:   */
    782:   PetscFunctionReturn(PETSC_SUCCESS);
    783: }

    785: static 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)
    786: {
    787:   char *ropts;
    788:   char  ropts_par[PETSC_MAX_PATH_LEN], ropts_pargh[PETSC_MAX_PATH_LEN];
    789:   char  ropts_dbg[PETSC_MAX_PATH_LEN];

    791:   PetscFunctionBegin;
    792:   PetscCall(PetscMalloc1(PETSC_MAX_PATH_LEN, &ropts));
    793:   PetscCall(PetscMemzero(&ropts_par, PETSC_MAX_PATH_LEN));
    794:   PetscCall(PetscMemzero(&ropts_pargh, PETSC_MAX_PATH_LEN));
    795:   PetscCall(PetscMemzero(&ropts_dbg, PETSC_MAX_PATH_LEN));

    797:   /* do parallel read unless using only one processor */
    798:   if (numproc > 1) {
    799:     // PetscCall(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":"")));
    800:     PetscCall(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;" : ""));
    801:     if (nghost) PetscCall(PetscSNPrintf(ropts_pargh, PETSC_MAX_PATH_LEN, "PARALLEL_GHOSTS=%" PetscInt_FMT ".0.%" PetscInt_FMT ";", dim, nghost));
    802:   }

    804:   if (dbglevel) {
    805:     if (numproc > 1) {
    806:       PetscCall(PetscSNPrintf(ropts_dbg, PETSC_MAX_PATH_LEN, "CPUTIME;DEBUG_IO=%" PetscInt_FMT ";DEBUG_PIO=%" PetscInt_FMT ";", dbglevel, dbglevel));
    807:     } else PetscCall(PetscSNPrintf(ropts_dbg, PETSC_MAX_PATH_LEN, "CPUTIME;DEBUG_IO=%" PetscInt_FMT ";", dbglevel));
    808:   }

    810:   PetscCall(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 : ""));
    811:   *read_opts = ropts;
    812:   PetscFunctionReturn(PETSC_SUCCESS);
    813: }

    815: /*@C
    816:   DMMoabLoadFromFile - Creates a `DMMOAB` object by loading the mesh from a user specified file
    817:   <https://www.mcs.anl.gov/~fathom/moab-docs/html/contents.html#fivetwo>

    819:   Collective

    821:   Input Parameters:
    822: + comm        - The communicator for the `DMOAB` object
    823: . dim         - The spatial dimension
    824: . nghost      - The number of ghosted layers needed in the partitioned mesh
    825: . filename    - The name of the mesh file to be loaded
    826: - usrreadopts - The options string to read a MOAB mesh.

    828:   Output Parameter:
    829: . dm - The `DM` object

    831:   Level: beginner

    833: .seealso: `DMSetType()`, `DMCreate()`, `DMMoabCreateBoxMesh()`
    834: @*/
    835: PetscErrorCode DMMoabLoadFromFile(MPI_Comm comm, PetscInt dim, PetscInt nghost, const char *filename, const char *usrreadopts, DM *dm)
    836: {
    837:   moab::ErrorCode  merr;
    838:   PetscInt         nprocs;
    839:   DM_Moab         *dmmoab;
    840:   moab::Interface *mbiface;
    841: #ifdef MOAB_HAVE_MPI
    842:   moab::ParallelComm *pcomm;
    843: #endif
    844:   moab::Range verts, elems;
    845:   const char *readopts;

    847:   PetscFunctionBegin;
    848:   PetscAssertPointer(dm, 6);

    850:   /* Create the basic DMMoab object and keep the default parameters created by DM impls */
    851:   PetscCall(DMMoabCreateMoab(comm, NULL, NULL, NULL, dm));

    853:   /* get all the necessary handles from the private DM object */
    854:   dmmoab  = (DM_Moab *)(*dm)->data;
    855:   mbiface = dmmoab->mbiface;
    856: #ifdef MOAB_HAVE_MPI
    857:   pcomm  = dmmoab->pcomm;
    858:   nprocs = pcomm->size();
    859: #else
    860:   nprocs = 1;
    861: #endif
    862:   /* TODO: Decipher dimension based on the loaded mesh instead of getting from user */
    863:   dmmoab->dim         = dim;
    864:   dmmoab->nghostrings = nghost;
    865:   dmmoab->refct       = 1;

    867:   /* create a file set to associate all entities in current mesh */
    868:   merr = dmmoab->mbiface->create_meshset(moab::MESHSET_SET, dmmoab->fileset);
    869:   MBERR("Creating file set failed", merr);

    871:   /* add mesh loading options specific to the DM */
    872:   PetscCall(DMMoab_GetReadOptions_Private(dmmoab->partition_by_rank, nprocs, dim, nghost, dmmoab->read_mode, dmmoab->rw_dbglevel, dmmoab->extra_read_options, usrreadopts, &readopts));

    874:   PetscCall(PetscInfo(*dm, "Reading file %s with options: %s\n", filename, readopts));

    876:   /* Load the mesh from a file. */
    877:   if (dmmoab->fileset) {
    878:     merr = mbiface->load_file(filename, &dmmoab->fileset, readopts);
    879:     MBERRVM(mbiface, "Reading MOAB file failed.", merr);
    880:   } else {
    881:     merr = mbiface->load_file(filename, 0, readopts);
    882:     MBERRVM(mbiface, "Reading MOAB file failed.", merr);
    883:   }

    885: #ifdef MOAB_HAVE_MPI
    886:   /* Reassign global IDs on all entities. */
    887:   /* merr = pcomm->assign_global_ids(dmmoab->fileset, dim, 1, true, true, true);MBERRNM(merr); */
    888: #endif

    890:   /* load the local vertices */
    891:   merr = mbiface->get_entities_by_type(dmmoab->fileset, moab::MBVERTEX, verts, true);
    892:   MBERRNM(merr);
    893:   /* load the local elements */
    894:   merr = mbiface->get_entities_by_dimension(dmmoab->fileset, dim, elems, true);
    895:   MBERRNM(merr);

    897: #ifdef MOAB_HAVE_MPI
    898:   /* Everything is set up, now just do a tag exchange to update tags
    899:      on all of the ghost vertexes */
    900:   merr = pcomm->exchange_tags(dmmoab->ltog_tag, verts);
    901:   MBERRV(mbiface, merr);
    902:   merr = pcomm->exchange_tags(dmmoab->ltog_tag, elems);
    903:   MBERRV(mbiface, merr);
    904:   merr = pcomm->collective_sync_partition();
    905:   MBERR("Collective sync failed", merr);
    906: #endif

    908:   PetscCall(PetscInfo(*dm, "MOAB file '%s' was successfully loaded. Found %zu vertices and %zu elements.\n", filename, verts.size(), elems.size()));
    909:   PetscCall(PetscFree(readopts));
    910:   PetscFunctionReturn(PETSC_SUCCESS);
    911: }

    913: /*@C
    914:   DMMoabRenumberMeshEntities - Order and number all entities (vertices->elements) to be contiguously ordered
    915:   in parallel

    917:   Collective

    919:   Input Parameters:
    920: . dm - The DM object

    922:   Level: advanced

    924: .seealso: `DMSetUp()`, `DMCreate()`
    925: @*/
    926: PetscErrorCode DMMoabRenumberMeshEntities(DM dm)
    927: {
    928:   moab::Range verts;

    930:   PetscFunctionBegin;

    933: #ifdef MOAB_HAVE_MPI
    934:   /* Insert new points */
    935:   moab::ErrorCode merr;
    936:   merr = ((DM_Moab *)dm->data)->pcomm->assign_global_ids(((DM_Moab *)dm->data)->fileset, 3, 0, false, true, false);
    937:   MBERRNM(merr);
    938: #endif
    939:   PetscFunctionReturn(PETSC_SUCCESS);
    940: }