boost/libs/numeric/odeint/test/numeric/abm_time_dependent.cpp

/* Boost numeric test of the adams-bashforth-moulton steppers test file

 Copyright 2013 Karsten Ahnert
 Copyright 2013-2015 Mario Mulansky

 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)
*/

// disable checked iterator warning for msvc
#include <boost/config.hpp>
#ifdef BOOST_MSVC
    #pragma warning(disable:4996)
#endif

#define BOOST_TEST_MODULE numeric_adams_bashforth_moulton

#include <iostream>
#include <cmath>

#include <boost/test/unit_test.hpp>

#include <boost/mpl/vector.hpp>

#include <boost/numeric/odeint.hpp>

using namespace boost::unit_test;
using namespace boost::numeric::odeint;
namespace mpl = boost::mpl;

typedef double value_type;

typedef value_type state_type;


// simple time-dependent rhs, analytic solution x = 0.5*t^2
struct simple_rhs
{
    void operator()( const state_type& x , state_type &dxdt , const double t ) const
    {
        dxdt = t;
    }
};

BOOST_AUTO_TEST_SUITE( numeric_abm_time_dependent_test )


/* generic test for all adams bashforth moulton steppers */
template< class Stepper >
struct perform_abm_time_dependent_test
{
    void operator()( void )
    {
        Stepper stepper;
        const int o = stepper.order()+1; //order of the error is order of approximation + 1

        const state_type x0 = 0.0;
        state_type x1 = x0;
        double t = 0.0;
        double dt = 0.1;
        const int steps = 10;

        integrate_n_steps( boost::ref(stepper) , simple_rhs(), x1 , t , dt , steps );
        BOOST_CHECK_LT( std::abs( 0.5 - x1 ) , std::pow( dt , o ) );
    }
};

typedef mpl::vector<
    adams_bashforth_moulton< 2 , state_type > ,
    adams_bashforth_moulton< 3 , state_type > ,
    adams_bashforth_moulton< 4 , state_type > ,
    adams_bashforth_moulton< 5 , state_type > ,
    adams_bashforth_moulton< 6 , state_type > ,
    adams_bashforth_moulton< 7 , state_type > ,
    adams_bashforth_moulton< 8 , state_type >
    > adams_bashforth_moulton_steppers;

BOOST_AUTO_TEST_CASE_TEMPLATE( abm_time_dependent_test , Stepper, adams_bashforth_moulton_steppers )
{
    perform_abm_time_dependent_test< Stepper > tester;
    tester();
}

BOOST_AUTO_TEST_SUITE_END()