case1_test.cpp

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/*
 * case1_test.cpp
 *
 *  Created on: Feb 12, 2013
 */

// copy from par_sph_intx
// will save the LOC tag on the euler nodes? maybe
#include <iostream>
#include <cmath>  // for M_PI

#include "moab/Core.hpp"
#include "moab/Interface.hpp"
#include "moab/IntxMesh/Intx2MeshOnSphere.hpp"
#include "moab/ProgOptions.hpp"
#include "MBTagConventions.hpp"

#include "moab/IntxMesh/IntxUtils.hpp"
#include "IntxUtilsCSLAM.hpp"

#include "TestUtil.hpp"

using namespace moab;
// some input data
double gtol     = 0.0001;        // this is for geometry tolerance
double CubeSide = 6.;            // the above file starts with cube side 6; radius depends on cube side
double t = 0.1, delta_t = 0.43;  // check the script

ErrorCode manufacture_lagrange_mesh_on_sphere( Interface* mb, EntityHandle euler_set, EntityHandle& lagr_set )
{
    /*
     * get all quads first, then vertices, then move them on the surface of the sphere
     *  radius is in, it comes from MeshKit/python/examples/manufHomme.py :
     *  length = 6.
     *  each edge of the cube will be divided using this meshcount
     *  meshcount = 11
     *   circumscribed sphere radius
     *   radius = length * math.sqrt(3) /2
     */
    double radius = CubeSide / 2 * sqrt( 3. );  // our value depends on cube side
    Range quads;
    ErrorCode rval = mb->get_entities_by_type( euler_set, MBQUAD, quads );
    if( MB_SUCCESS != rval ) return rval;

    Range connecVerts;
    rval = mb->get_connectivity( quads, connecVerts );
    if( MB_SUCCESS != rval ) return rval;

    // create new set
    rval = mb->create_meshset( MESHSET_SET, lagr_set );
    if( MB_SUCCESS != rval ) return rval;

    // get the coordinates of the old mesh, and move it around the sphere according to case 1
    // now put the vertices in the right place....
    // int vix=0; // vertex index in new array

    // first create departure points (vertices in the lagrange mesh)
    // then connect them in quads
    std::map< EntityHandle, EntityHandle > newNodes;
    for( Range::iterator vit = connecVerts.begin(); vit != connecVerts.end(); ++vit )
    {
        EntityHandle oldV = *vit;
        CartVect posi;
        rval = mb->get_coords( &oldV, 1, &( posi[0] ) );
        if( MB_SUCCESS != rval ) return rval;
        // Intx utils, case 1
        CartVect newPos;
        IntxUtilsCSLAM::departure_point_case1( posi, t, delta_t, newPos );
        newPos = radius * newPos;
        EntityHandle new_vert;
        rval = mb->create_vertex( &( newPos[0] ), new_vert );
        if( MB_SUCCESS != rval ) return rval;
        newNodes[oldV] = new_vert;
    }
    for( Range::iterator it = quads.begin(); it != quads.end(); ++it )
    {
        EntityHandle q = *it;
        int nnodes;
        const EntityHandle* conn4;
        rval = mb->get_connectivity( q, conn4, nnodes );
        if( MB_SUCCESS != rval ) return rval;
        EntityHandle new_conn[4];
        for( int i = 0; i < nnodes; i++ )
        {
            EntityHandle v1 = conn4[i];
            new_conn[i]     = newNodes[v1];
        }
        EntityHandle new_quad;
        rval = mb->create_element( MBQUAD, new_conn, 4, new_quad );
        if( MB_SUCCESS != rval ) return rval;
        rval = mb->add_entities( lagr_set, &new_quad, 1 );
        if( MB_SUCCESS != rval ) return rval;
    }

    return rval;
}
int main( int argc, char** argv )
{

    const char* filename_mesh1 = STRINGIFY( MESHDIR ) "/mbcslam/eulerHomme.vtk";
    if( argc > 1 )
    {
        int index = 1;
        while( index < argc )
        {
            if( !strcmp( argv[index], "-gtol" ) )  // this is for geometry tolerance
            {
                gtol = atof( argv[++index] );
            }
            if( !strcmp( argv[index], "-cube" ) )
            {
                CubeSide = atof( argv[++index] );
            }
            if( !strcmp( argv[index], "-dt" ) )
            {
                delta_t = atof( argv[++index] );
            }
            if( !strcmp( argv[index], "-input" ) )
            {
                filename_mesh1 = argv[++index];
            }
            index++;
        }
    }
    std::cout << " case 1: use -gtol " << gtol << " -dt " << delta_t << " -cube " << CubeSide << " -input "
              << filename_mesh1 << "\n";

    Core moab;
    Interface& mb = moab;
    EntityHandle euler_set;
    ErrorCode rval;
    rval = mb.create_meshset( MESHSET_SET, euler_set );
    if( MB_SUCCESS != rval ) return 1;

    rval = mb.load_file( filename_mesh1, &euler_set );

    if( MB_SUCCESS != rval ) return 1;

    // everybody will get a DP tag, including the non owned entities; so exchange tags is not
    // required for LOC (here)
    EntityHandle lagrange_set;
    rval = manufacture_lagrange_mesh_on_sphere( &mb, euler_set, lagrange_set );
    if( MB_SUCCESS != rval ) return 1;
    rval = mb.write_file( "lagrIni.h5m", 0, 0, &lagrange_set, 1 );
    if( MB_SUCCESS != rval ) std::cout << "can't write lagr set\n";

    rval = moab::IntxUtils::enforce_convexity( &mb, lagrange_set );
    if( MB_SUCCESS != rval ) return 1;

    rval = mb.write_file( "lagr.h5m", 0, 0, &lagrange_set, 1 );
    if( MB_SUCCESS != rval ) std::cout << "can't write lagr set\n";

    Intx2MeshOnSphere worker( &mb );

    double radius = CubeSide / 2 * sqrt( 3. );  // input

    worker.set_radius_source_mesh( radius );
    worker.set_radius_destination_mesh( radius );

    // worker.SetEntityType(MBQUAD);

    worker.set_error_tolerance( gtol );
    std::cout << "error tolerance epsilon_1=" << gtol << "\n";

    EntityHandle outputSet;
    rval = mb.create_meshset( MESHSET_SET, outputSet );
    if( MB_SUCCESS != rval ) return 1;
    rval = worker.FindMaxEdges( lagrange_set, euler_set );
    if( MB_SUCCESS != rval ) return 1;
    rval = worker.intersect_meshes( lagrange_set, euler_set, outputSet );
    if( MB_SUCCESS != rval ) return 1;

    // std::string opts_write("");
    std::stringstream outf;
    outf << "intersect1"
         << ".h5m";
    rval = mb.write_file( outf.str().c_str(), 0, 0, &outputSet, 1 );
    if( MB_SUCCESS != rval ) std::cout << "can't write output\n";

    moab::IntxAreaUtils sphAreaUtils;
    double intx_area    = sphAreaUtils.area_on_sphere( &mb, outputSet, radius );
    double arrival_area = sphAreaUtils.area_on_sphere( &mb, euler_set, radius );
    std::cout << " Arrival area: " << arrival_area << "  intersection area:" << intx_area
              << " rel error: " << fabs( ( intx_area - arrival_area ) / arrival_area ) << "\n";
    if( MB_SUCCESS != rval ) return 1;

    return 0;
}