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/*
[auto_generated]
libs/numeric/odeint/test/implicit_euler.cpp
[begin_description]
This file tests the implicit Euler stepper.
[end_description]
Copyright 2010-2011 Mario Mulansky
Copyright 2010-2012 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)
*/
// disable checked iterator warning for msvc
#include <boost/config.hpp>
#ifdef BOOST_MSVC
#pragma warning(disable:4996)
#endif
#define BOOST_TEST_MODULE odeint_implicit_euler
#include <boost/test/unit_test.hpp>
#include <utility>
#include <iostream>
#include <boost/numeric/odeint/stepper/implicit_euler.hpp>
//#include <boost/numeric/odeint/util/ublas_resize.hpp>
#include <boost/numeric/ublas/vector.hpp>
#include <boost/numeric/ublas/matrix.hpp>
using namespace boost::unit_test;
using namespace boost::numeric::odeint;
typedef double value_type;
typedef boost::numeric::ublas::vector< value_type > state_type;
typedef boost::numeric::ublas::matrix< value_type > matrix_type;
/* use functors, because functions don't work with msvc 10, I guess this is a bug */
struct sys
{
void operator()( const state_type &x , state_type &dxdt , const value_type t ) const
{
dxdt( 0 ) = x( 0 ) + 2 * x( 1 );
dxdt( 1 ) = x( 1 );
}
};
struct jacobi
{
void operator()( const state_type &x , matrix_type &jacobi , const value_type t ) const
{
jacobi( 0 , 0 ) = 1;
jacobi( 0 , 1 ) = 2;
jacobi( 1 , 0 ) = 0;
jacobi( 1 , 1 ) = 1;
}
};
BOOST_AUTO_TEST_SUITE( implicit_euler_test )
BOOST_AUTO_TEST_CASE( test_euler )
{
implicit_euler< value_type > stepper;
state_type x( 2 );
x(0) = 0.0; x(1) = 1.0;
value_type eps = 1E-12;
/* make_pair doesn't work with function pointers on msvc 10 */
stepper.do_step( std::make_pair( sys() , jacobi() ) , x , 0.0 , 0.1 );
using std::abs;
// compare with analytic solution of above system
BOOST_CHECK_MESSAGE( abs( x(0) - 20.0/81.0 ) < eps , x(0) - 20.0/81.0 );
BOOST_CHECK_MESSAGE( abs( x(1) - 10.0/9.0 ) < eps , x(0) - 10.0/9.0 );
}
BOOST_AUTO_TEST_SUITE_END()
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