odeint/performance/rt_generic_rk4_phase_lattice.cpp

/*
 * rt_generic_rk4_lorenz.cpp
 *
 * Copyright 2011 Mario Mulansky
 * Copyright 2012 Karsten Ahnert
 *
 * Distributed under the Boost Software License, Version 1.0.
 * (See accompanying file LICENSE_1_0.txt or
 * copy at http://www.boost.org/LICENSE_1_0.txt)
 */


#include <boost/array.hpp>

#include "rt_explicit_rk.hpp"

#include "rk_performance_test_case.hpp"

#include "phase_lattice.hpp"

const size_t N = 1024;

typedef boost::array< double , N > state_type;

typedef rt_explicit_rk< state_type > rk_stepper_type;

const size_t stage_count = 4;


class rt_generic_wrapper
{
public:

    rt_generic_wrapper( const double * const * a , 
                        const rk_stepper_type::coeff_b_type &b ,
                        const rk_stepper_type::coeff_c_type &c ) 
        : m_stepper( stage_count , 
                     (rk_stepper_type::coeff_a_type) a , b , c )
    { }

    void reset_init_cond()
    {
        for( size_t i = 0 ; i<N ; ++i )
            m_x[i] = 2.0*3.1415927*rand() / RAND_MAX;
        m_t = 0.0;
    }

    inline void do_step( const double dt )
    {
        m_stepper.do_step( phase_lattice<N>() , m_x , m_t , dt );
        //m_t += dt;
    }

    double state( const size_t i ) const
    { return m_x[i]; }

private:
    state_type m_x;
    double m_t;
    rk_stepper_type m_stepper;
};



int main()
{
    srand( 12312354 );

    const double a_tmp[3*4/2] = { 0.5 ,
                                  0.0 , 1.0 ,
                                  0.0 , 0.0 , 1.0 };
    const double* const a[3] = { a_tmp , a_tmp+1 , a_tmp+3 };

    rk_stepper_type::coeff_b_type b( stage_count );
    b[0] = 1.0/6; b[1] = 1.0/3; b[2] = 1.0/3; b[3] = 1.0/6;
    
    rk_stepper_type::coeff_c_type c( stage_count );
    c[0] = 0.0; c[1] = 0.5; c[2] = 0.5; c[3] = 1.0;

    rt_generic_wrapper stepper( a , b , c );

    run( stepper , 10000 , 1E-6 );
}