measure.cpp

Go to the documentation of this file.

/*
 * Copyright (c) 2005 Lawrence Livermore National Laboratory under
 * contract number B545069 with the University of Wisconsin - Madison.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
 
#include "moab/CartVect.hpp"
#include "measure.hpp"
using namespace moab;
 
inline static double tet_volume( const CartVect& v0, const CartVect& v1, const CartVect& v2, const CartVect& v3 )
{
 return 1. / 6. * ( ( ( v1 - v0 ) * ( v2 - v0 ) ) % ( v3 - v0 ) );
}
 
double edge_length( const double* start_vtx_coords, const double* end_vtx_coords )
{
 const CartVect* start = reinterpret_cast< const CartVect* >( start_vtx_coords );
 const CartVect* end = reinterpret_cast< const CartVect* >( end_vtx_coords );
 return ( *start - *end ).length();
}
 
double measure( moab::EntityType type, int num_vertices, const double* vertex_coordinates )
{
 const CartVect* coords = reinterpret_cast< const CartVect* >( vertex_coordinates );
 switch( type )
 {
 case moab::MBEDGE:
 return ( coords[0] - coords[1] ).length();
 case moab::MBTRI:
 return 0.5 * ( ( coords[1] - coords[0] ) * ( coords[2] - coords[0] ) ).length();
 case moab::MBQUAD:
 num_vertices = 4;
 // fall through
 case moab::MBPOLYGON: {
 CartVect mid( 0, 0, 0 );
 for( int i = 0; i < num_vertices; ++i )
 mid += coords[i];
 mid /= num_vertices;
 
 double sum = 0.0;
 for( int i = 0; i < num_vertices; ++i )
 {
 int j = ( i + 1 ) % num_vertices;
 sum += ( ( mid - coords[i] ) * ( mid - coords[j] ) ).length();
 }
 return 0.5 * sum;
 }
 case moab::MBTET:
 return tet_volume( coords[0], coords[1], coords[2], coords[3] );
 case moab::MBPYRAMID:
 return tet_volume( coords[0], coords[1], coords[2], coords[4] ) +
 tet_volume( coords[0], coords[2], coords[3], coords[4] );
 case moab::MBPRISM:
 return tet_volume( coords[0], coords[1], coords[2], coords[5] ) +
 tet_volume( coords[3], coords[5], coords[4], coords[0] ) +
 tet_volume( coords[1], coords[4], coords[5], coords[0] );
 case moab::MBHEX:
 return tet_volume( coords[0], coords[1], coords[3], coords[4] ) +
 tet_volume( coords[7], coords[3], coords[6], coords[4] ) +
 tet_volume( coords[4], coords[5], coords[1], coords[6] ) +
 tet_volume( coords[1], coords[6], coords[3], coords[4] ) +
 tet_volume( coords[2], coords[6], coords[3], coords[1] );
 default:
 return 0.0;
 }
}