/* Boost check_gmp.cpp test file

 Copyright 2009 Karsten Ahnert
 Copyright 2009 Mario Mulansky

 This file tests the odeint library with the gmp arbitrary precision types

 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)
*/

#define BOOST_TEST_MODULE odeint_gmp

#include <iostream>

#include <gmpxx.h>

#include <boost/test/unit_test.hpp>
#include <boost/array.hpp>

#include <boost/mpl/vector.hpp>

#include <boost/numeric/odeint.hpp>
//#include <boost/numeric/odeint/algebra/vector_space_algebra.hpp>

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

namespace mpl = boost::mpl;

const int precision = 1024;

typedef mpf_class value_type;
typedef mpf_class state_type;

//provide min, max and pow functions for mpf types - required for controlled steppers
value_type min( const value_type a , const value_type b )
{
    if( a<b ) return a;
    else return b;
}
value_type max( const value_type a , const value_type b )
{
    if( a>b ) return a;
    else return b;
}
value_type pow( const value_type a , const value_type b )
{
    // do calculation in double precision
    return value_type( std::pow( a.get_d() , b.get_d() ) );
}


//provide vector_space reduce:

namespace boost { namespace numeric { namespace odeint {

template<>
struct vector_space_reduce< state_type >
{
  template< class Op >
  state_type operator()( state_type x , Op op , state_type init ) const
  {
      init = op( init , x );
      return init;
  }
};

} } }


void constant_system( const state_type &x , state_type &dxdt , value_type t )
{
    dxdt = value_type( 1.0 , precision );
}


/* check runge kutta stepers */
typedef mpl::vector<
    euler< state_type , value_type , state_type , value_type , vector_space_algebra > ,
    modified_midpoint< state_type , value_type , state_type , value_type , vector_space_algebra > ,
    runge_kutta4< state_type , value_type , state_type , value_type , vector_space_algebra > ,
    runge_kutta4_classic< state_type , value_type , state_type , value_type , vector_space_algebra > ,
    runge_kutta_cash_karp54_classic< state_type , value_type , state_type , value_type , vector_space_algebra > ,
    runge_kutta_cash_karp54< state_type , value_type , state_type , value_type , vector_space_algebra > ,
    runge_kutta_dopri5< state_type , value_type , state_type , value_type , vector_space_algebra > ,
    runge_kutta_fehlberg78< state_type , value_type , state_type , value_type , vector_space_algebra >
    > stepper_types;


template< class Stepper >
struct perform_runge_kutta_test {

    void operator()( void )
    {
        /* We have to specify the desired precision in advance! */
        mpf_set_default_prec( precision );

        mpf_t eps_ , unity;
        mpf_init( eps_ ); mpf_init( unity );
        mpf_set_d( unity , 1.0 );
        mpf_div_2exp( eps_ , unity , precision-1 ); // 2^(-precision+1) : smallest number that can be represented with used precision
        value_type eps( eps_ );

        Stepper stepper;
        state_type x;
        x = 0.0;

        stepper.do_step( constant_system , x , 0.0 , 0.1 );

        BOOST_MESSAGE( eps );
        BOOST_CHECK_MESSAGE( abs( x - value_type( 0.1 , precision ) ) < eps , x - 0.1 );
    }
};


BOOST_AUTO_TEST_CASE_TEMPLATE( runge_kutta_stepper_test , Stepper , stepper_types )
{
    perform_runge_kutta_test< Stepper > tester;
    tester();
}


/* check controlled steppers */
typedef mpl::vector<
    controlled_runge_kutta< runge_kutta_cash_karp54_classic< state_type , value_type , state_type , value_type , vector_space_algebra > > ,
    controlled_runge_kutta< runge_kutta_dopri5< state_type , value_type , state_type , value_type , vector_space_algebra > > , 
    controlled_runge_kutta< runge_kutta_fehlberg78< state_type , value_type , state_type , value_type , vector_space_algebra > > ,
    bulirsch_stoer< state_type , value_type , state_type , value_type , vector_space_algebra >
    > controlled_stepper_types;


template< class Stepper >
struct perform_controlled_test {

    void operator()( void )
    {
        mpf_set_default_prec( precision );

        mpf_t eps_ , unity;
        mpf_init( eps_ ); mpf_init( unity );
        mpf_set_d( unity , 1.0 );
        mpf_div_2exp( eps_ , unity , precision-1 ); // 2^(-precision+1) : smallest number that can be represented with used precision
        value_type eps( eps_ );

        Stepper stepper;
        state_type x;
        x = 0.0;

        value_type t(0.0);
        value_type dt(0.1);

        stepper.try_step( constant_system , x , t , dt );

        BOOST_MESSAGE( eps );
        BOOST_CHECK_MESSAGE( abs( x - value_type( 0.1 , precision ) ) < eps , x - 0.1 );
    }
};

BOOST_AUTO_TEST_CASE_TEMPLATE( controlled_stepper_test , Stepper , controlled_stepper_types )
{
    perform_controlled_test< Stepper > tester;
    tester();
}
