HelloMOAB.cpp

Description: read a mesh, get the entities.
HelloMOAB is a simple test file which is used to read meshes from VTK file and test how many entities there are.
To run: ./HelloMOAB [meshfile]
(default values can run if users don't specify a mesh file)

/** @example HelloMOAB.cpp
 * Description: read a mesh, get the entities.\n
 * HelloMOAB is a simple test file which is used to read meshes from VTK file and test how many
 * entities there are.\n
 *
 * To run: ./HelloMOAB [meshfile]\n
 * (default values can run if users don't specify a mesh file)
 */
 
#include "moab/Core.hpp"
#include <iostream>
 
using namespace moab;
using namespace std;
 
#ifndef MESH_DIR
#define MESH_DIR "."
#endif
 
// Note: change the file name below to test a trivial "No such file or directory" error
string test_file_name = string( MESH_DIR ) + string( "/3k-tri-sphere.vtk" );
 
int main( int argc, char** argv )
{
    // Get MOAB instance
    Interface* mb = new( std::nothrow ) Core;
    if( NULL == mb ) return 1;
 
    // Need option handling here for input filename
    if( argc > 1 )
    {
        // User has input a mesh file
        test_file_name = argv[1];
    }
 
    // Load the mesh from vtk file
    ErrorCode rval = mb->load_mesh( test_file_name.c_str() );MB_CHK_ERR( rval );
 
    // Get verts entities, by type
    Range verts;
    rval = mb->get_entities_by_type( 0, MBVERTEX, verts );MB_CHK_ERR( rval );
 
    // Get edge entities, by type
    Range edges;
    rval = mb->get_entities_by_type( 0, MBEDGE, edges );MB_CHK_ERR( rval );
 
    // Get faces, by dimension, so we stay generic to entity type
    Range faces;
    rval = mb->get_entities_by_dimension( 0, 2, faces );MB_CHK_ERR( rval );
 
    // Get regions, by dimension, so we stay generic to entity type
    Range elems;
    rval = mb->get_entities_by_dimension( 0, 3, elems );MB_CHK_ERR( rval );
 
    // Output the number of entities
    cout << "Number of vertices is " << verts.size() << endl;
    cout << "Number of edges is " << edges.size() << endl;
    cout << "Number of faces is " << faces.size() << endl;
    cout << "Number of elements is " << elems.size() << endl;
 
    delete mb;
 
    return 0;
}