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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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