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- /*
- [auto_generated]
- libs/numeric/odeint/test/euler_stepper.cpp
- [begin_description]
- This file tests explicit Euler stepper.
- [end_description]
- 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)
- */
- #define BOOST_TEST_MODULE odeint_explicit_euler
- #include <boost/test/unit_test.hpp>
- #include <utility>
- #include <iostream>
- #include <vector>
- #include <boost/numeric/odeint/stepper/euler.hpp>
- #include <boost/numeric/odeint/algebra/range_algebra.hpp>
- using namespace boost::unit_test;
- using namespace boost::numeric::odeint;
- // test with own vector implementation
- class my_vec : public std::vector< double > {
- public:
- my_vec() : std::vector< double >()
- { }
- my_vec( const my_vec &x ) : std::vector< double >( x )
- { }
- my_vec( size_t dim )
- : std::vector< double >( dim )
- { }
- };
- namespace boost {
- namespace numeric {
- namespace odeint {
- template<>
- struct is_resizeable< my_vec >
- {
- //struct type : public boost::true_type { };
- typedef boost::true_type type;
- const static bool value = type::value;
- };
- } } }
- typedef double value_type;
- //typedef std::vector< value_type > state_type;
- typedef my_vec state_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
- {
- std::cout << "sys start " << dxdt.size() << std::endl;
- dxdt[0] = x[0] + 2 * x[1];
- dxdt[1] = x[1];
- std::cout << "sys done" << std::endl;
- }
- };
- BOOST_AUTO_TEST_SUITE( explicit_euler_test )
- BOOST_AUTO_TEST_CASE( test_euler )
- {
- range_algebra algebra;
- euler< state_type > stepper( algebra );
- state_type x( 2 );
- x[0] = 0.0; x[1] = 1.0;
- std::cout << "initialized" << std::endl;
- const value_type eps = 1E-12;
- const value_type dt = 0.1;
- stepper.do_step( sys() , x , 0.0 , dt );
- using std::abs;
- // compare with analytic solution of above system
- BOOST_CHECK_MESSAGE( abs( x[0] - 2.0*1.0*dt ) < eps , x[0] - 2.0*1.0*dt );
- BOOST_CHECK_MESSAGE( abs( x[1] - (1.0 + dt) ) < eps , x[1] - (1.0+dt) );
- }
- BOOST_AUTO_TEST_SUITE_END()
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