1: static char help[] = "Simple MOAB example\n\n";

  3: #include <petscdmmoab.h>
  4: #include "moab/ScdInterface.hpp"

  6: typedef struct {
  7:   DM            dm;                /* DM implementation using the MOAB interface */
  8:   PetscLogEvent createMeshEvent;
  9:   /* Domain and mesh definition */
 10:   PetscInt dim;
 11:   char filename[PETSC_MAX_PATH_LEN];
 12:   char tagname[PETSC_MAX_PATH_LEN];
 13: } AppCtx;

 17: PetscErrorCode ProcessOptions(MPI_Comm comm, AppCtx *options)
 18: {
 20:   PetscBool      flg;

 23:   PetscStrcpy(options->filename, "");
 24:   PetscStrcpy(options->tagname, "petsc_tag");
 25:   options->dim = -1;

 27:   PetscOptionsBegin(comm, "", "MOAB example options", "DMMOAB");
 28:   PetscOptionsInt("-dim", "The topological mesh dimension", "ex1.c", options->dim, &options->dim, NULL);
 29:   PetscOptionsString("-filename", "The file containing the mesh", "ex1.c", options->filename, options->filename, sizeof(options->filename), NULL);
 30:   PetscOptionsString("-tagname", "The tag name from which to create a vector", "ex1.c", options->tagname, options->tagname, sizeof(options->tagname), &flg);
 31:   PetscOptionsEnd();

 33:   PetscLogEventRegister("CreateMesh",          DM_CLASSID,   &options->createMeshEvent);
 34:   return(0);
 35: };

 39: PetscErrorCode CreateMesh(MPI_Comm comm, AppCtx *user, DM *dm)
 40: {
 41:   moab::Interface *iface=NULL;
 42:   moab::ParallelComm *pcomm=NULL;
 43:   moab::Tag tag=NULL;
 44:   moab::Tag ltog_tag=NULL;
 45:   moab::Range range;
 46:   PetscInt tagsize;
 47:   moab::ErrorCode merr;

 51:   PetscLogEventBegin(user->createMeshEvent,0,0,0,0);
 52:   DMMoabCreateMoab(comm, iface, pcomm, &ltog_tag, &range, dm);
 53:   std::cout << "Created DMMoab using DMMoabCreateMoab." << std::endl;
 54:   DMMoabGetInterface(*dm, &iface);

 56:     // load file and get entities of requested or max dimension
 57:   if (strlen(user->filename) > 0) {
 58:     merr = iface->load_file(user->filename);MBERRNM(merr);
 59:     std::cout << "Read mesh from file " << user->filename << std::endl;
 60:   }
 61:   else {
 62:       // make a simple structured mesh
 63:     moab::ScdInterface *scdi;
 64:     merr = iface->query_interface(scdi);

 66:     moab::ScdBox *box;
 67:     merr = scdi->construct_box (moab::HomCoord(0,0,0), moab::HomCoord(5,5,5), NULL, 0, box);MBERRNM(merr);
 68:     user->dim = 3;
 69:     merr = iface->set_dimension(user->dim);MBERRNM(merr);
 70:     std::cout << "Created structured 5x5x5 mesh." << std::endl;
 71:   }
 72:   if (-1 == user->dim) {
 73:     moab::Range tmp_range;
 74:     merr = iface->get_entities_by_handle(0, tmp_range);MBERRNM(merr);
 75:     if (tmp_range.empty()) {
 76:       MBERRNM(moab::MB_FAILURE);
 77:     }
 78:     user->dim = iface->dimension_from_handle(*tmp_range.rbegin());
 79:   }
 80:   merr = iface->get_entities_by_dimension(0, user->dim, range);MBERRNM(merr);
 81:   DMMoabSetLocalVertices(*dm, &range);

 83:     // get the requested tag and create if necessary
 84:   std::cout << "Creating tag with name: " << user->tagname << ";\n";
 85:   merr = iface->tag_get_handle(user->tagname, 1, moab::MB_TYPE_DOUBLE, tag, moab::MB_TAG_CREAT | moab::MB_TAG_DENSE);MBERRNM(merr);
 86:   {
 87:       // initialize new tag with gids
 88:     std::vector<double> tag_vals(range.size());
 89:     merr = iface->tag_get_data(ltog_tag, range, tag_vals.data());MBERRNM(merr); // read them into ints
 90:     double *dval = tag_vals.data(); int *ival = reinterpret_cast<int*>(dval); // "stretch" them into doubles, from the end
 91:     for (int i = tag_vals.size()-1; i >= 0; i--) dval[i] = ival[i];
 92:     merr = iface->tag_set_data(tag, range, tag_vals.data());MBERRNM(merr); // write them into doubles
 93:   }
 94:   merr = iface->tag_get_length(tag, tagsize);MBERRNM(merr);

 96:   DMSetUp(*dm);

 98:     // create the dmmoab and initialize its data
 99:   PetscObjectSetName((PetscObject) *dm, "MOAB mesh");
100:   PetscLogEventEnd(user->createMeshEvent,0,0,0,0);
101:   user->dm = *dm;
102:   return(0);
103: }

107: int main(int argc, char **argv)
108: {
109:   AppCtx         user;                 /* user-defined work context */
110:   moab::ErrorCode merr;
112:   Vec            vec;
113:   moab::Interface*  mbImpl=NULL;
114:   moab::Tag         datatag=NULL;

116:   PetscInitialize(&argc, &argv, NULL, help);
117:   ProcessOptions(PETSC_COMM_WORLD, &user);

119:   CreateMesh(PETSC_COMM_WORLD, &user, &user.dm); /* create the MOAB dm and the mesh */

121:   DMMoabGetInterface(user.dm, &mbImpl);
122:   merr = mbImpl->tag_get_handle(user.tagname, datatag);MBERRNM(merr);
123:   DMMoabCreateVector(user.dm, datatag, NULL, PETSC_TRUE, PETSC_FALSE,
124:                               &vec); /* create a vec from user-input tag */

126:   std::cout << "Created VecMoab from existing tag." << std::endl;
127:   VecDestroy(&vec);
128:   std::cout << "Destroyed VecMoab." << std::endl;
129:   DMDestroy(&user.dm);
130:   std::cout << "Destroyed DMMoab." << std::endl;
131:   PetscFinalize();
132:   return 0;
133: }