TestExodusII.cpp

This example demonstrates how to retrieve material, dirichlet and neumann sets from an ExodusII file.
Sets in MOAB contain entities and have a tag on them to give meaning to the entities. Tag names: MATERIAL_SET", "DIRICHLET_SET" and "NEUMANN_SET" are reserved and are associated with their corresponding entity sets. Sets are traversed to find out the type number of entities contained in each set.

Steps in this example :

1. Instantiate MOAB
2. Get input mesh file name and load it.
3. Loop over the three sets: material, dirichlet and neumann
   1. Get TagHandle and EntitySet(corresponding to the TagHandle)
   2. Loop thru all the EntitySet's
      1. Get the set id and entities in this set
4. Destroy the MOAB instance

To compile: make TestExodusII MOAB_DIR=<installdir>

To run:

1. TestExodusII <mesh-file>
   
2. TestExodusII (This uses the default <mesh-file>: <MOAB_SRC_DIR>/MeshFiles/unittest/mbtest2.g)

#include <iostream>

// Include header for MOAB instance and range
#include "moab/Core.hpp"

int main(int argc, char **argv) {

  // instantiate & load a file
  moab::Interface *mb = new moab::Core();

  // If no input is specified load ../MeshFiles/unittest/mbtest2.g
//  const char* test_file_name =  "../MeshFiles/unittest/mbtest2.g";

  // get the material set tag handle
  moab::Tag mtag;
  moab::ErrorCode rval;
  const char *tag_nms[] = {"MATERIAL_SET", "DIRICHLET_SET", "NEUMANN_SET"};
  moab::Range sets, set_ents;

  if (argc == 1) {
      std::cout << "Running default case, loading ../MeshFiles/unittest/mbtest2.g" << std::endl;
      std::cout << "Usage: " << argv[0] << " <filename>\n" << std::endl;
      rval = mb->load_file("../MeshFiles/unittest/mbtest2.g");
    }
  else{
      rval = mb->load_file(argv[argc-1]);
      std::cout << "Loaded mesh file: " << argv[argc-1] << std::endl;
    }

  // loop over set types
  for (int i = 0; i < 3; i++) {
      rval = mb->tag_get_handle(tag_nms[i], 1, moab::MB_TYPE_INTEGER, mtag);
      if (moab::MB_SUCCESS != rval) return 1;

      // get all the sets of that type in the mesh
      sets.clear();
      rval = mb->get_entities_by_type_and_tag(0, moab::MBENTITYSET, &mtag,
                                              NULL, 1, sets);
      if (moab::MB_SUCCESS != rval) return 1;

      // iterate over each set, getting entities
      moab::Range::iterator set_it;
      for (set_it = sets.begin(); set_it != sets.end(); set_it++)  {
          moab::EntityHandle this_set = *set_it;

          // get the id for this set
          int set_id;
          rval = mb->tag_get_data(mtag, &this_set, 1, &set_id);
          if (moab::MB_SUCCESS != rval) return 1;

          // get the entities in the set, recursively
          rval = mb->get_entities_by_handle(this_set, set_ents, true);
          if (moab::MB_SUCCESS != rval) return 1;

          std::cout << tag_nms[i] << " " << set_id << " has "
                    << set_ents.size() << " entities:" << std::endl;

          // print the entities contained in this set
          set_ents.print("   ");
          set_ents.clear();
        }
    }
  delete mb;
}