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- /*
- [auto_generated]
- libs/numeric/odeint/test/bulirsch_stoer.cpp
- [begin_description]
- This file tests the Bulirsch-Stoer 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)
- */
- // disable checked iterator warning for msvc
- #include <boost/config.hpp>
- #ifdef BOOST_MSVC
- #pragma warning(disable:4996)
- #endif
- #define BOOST_TEST_MODULE odeint_bulirsch_stoer
- #include <utility>
- #include <iostream>
- #include <boost/array.hpp>
- #include <boost/test/unit_test.hpp>
- #include <boost/numeric/odeint/stepper/bulirsch_stoer.hpp>
- #include <boost/numeric/odeint/stepper/bulirsch_stoer_dense_out.hpp>
- #include <boost/numeric/odeint/integrate/integrate_adaptive.hpp>
- using namespace boost::unit_test;
- using namespace boost::numeric::odeint;
- typedef double value_type;
- typedef boost::array< value_type , 3 > state_type;
- const double sigma = 10.0;
- const double R = 28.0;
- const double b = 8.0 / 3.0;
- struct lorenz
- {
- template< class State , class Deriv >
- void operator()( const State &x , Deriv &dxdt , double t ) const
- {
- dxdt[0] = sigma * ( x[1] - x[0] );
- dxdt[1] = R * x[0] - x[1] - x[0] * x[2];
- dxdt[2] = -b * x[2] + x[0] * x[1];
- }
- };
- struct const_system
- {
- template< class State , class Deriv >
- void operator()( const State &x , Deriv &dxdt , double t ) const
- {
- dxdt[0] = 1.0;
- dxdt[1] = 1.0;
- dxdt[2] = 1.0;
- }
- };
- struct sin_system
- {
- template< class State , class Deriv >
- void operator()( const State &x , Deriv &dxdt , double t ) const
- {
- dxdt[0] = sin( x[0] );
- dxdt[1] = cos( x[1] );
- dxdt[2] = sin( x[2] ) + cos( x[2] );
- }
- };
- BOOST_AUTO_TEST_SUITE( bulirsch_stoer_test )
- BOOST_AUTO_TEST_CASE( test_bulirsch_stoer )
- {
- typedef bulirsch_stoer< state_type > stepper_type;
- stepper_type stepper( 1E-9 , 1E-9 , 1.0 , 0.0 );
- state_type x;
- x[0] = 10.0 ; x[1] = 10.0 ; x[2] = 5.0;
- double dt = 0.1;
- //stepper.try_step( lorenz() , x , t , dt );
- std::cout << "starting integration..." << std::endl;
- size_t steps = integrate_adaptive( stepper , lorenz() , x , 0.0 , 10.0 , dt );
- std::cout << "required steps: " << steps << std::endl;
- bulirsch_stoer_dense_out< state_type > bs_do( 1E-9 , 1E-9 , 1.0 , 0.0 );
- x[0] = 10.0 ; x[1] = 10.0 ; x[2] = 5.0;
- double t = 0.0;
- dt = 1E-1;
- bs_do.initialize( x , t , dt );
- bs_do.do_step( sin_system() );
- std::cout << "one step successful, new time: " << bs_do.current_time() << " (" << t << ")" << std::endl;
- x = bs_do.current_state();
- std::cout << "x( " << bs_do.current_time() << " ) = [ " << x[0] << " , " << x[1] << " , " << x[2] << " ]" << std::endl;
- bs_do.calc_state( bs_do.current_time()/3 , x );
- std::cout << "x( " << bs_do.current_time()/3 << " ) = [ " << x[0] << " , " << x[1] << " , " << x[2] << " ]" << std::endl;
- std::cout << std::endl << "=======================================================================" << std::endl << std::endl;
- x[0] = 10.0 ; x[1] = 10.0 ; x[2] = 5.0;
- t = 0.0; dt /= 3;
- bs_do.initialize( x , t , dt );
- bs_do.do_step( sin_system() );
- x = bs_do.current_state();
- std::cout << "x( " << bs_do.current_time() << " ) = [ " << x[0] << " , " << x[1] << " , " << x[2] << " ]" << std::endl;
- t = dt;
- bs_do.initialize( x , t , dt );
- bs_do.do_step( sin_system() );
- x = bs_do.current_state();
- t = 2*dt;
- bs_do.initialize( x , t , dt );
- bs_do.do_step( sin_system() );
- x = bs_do.current_state();
- std::cout << "x( " << bs_do.current_time() << " ) = [ " << x[0] << " , " << x[1] << " , " << x[2] << " ]" << std::endl << std::endl << std::endl;
- }
- BOOST_AUTO_TEST_CASE( test_bulirsch_stoer_adjust_size )
- {
- typedef bulirsch_stoer< state_type > stepper_type;
- stepper_type stepper( 1E-9 , 1E-9 , 1.0 , 0.0 );
- state_type x; x[0] = 10.0 ; x[1] = 10.0 ; x[2] = 5.0;
- stepper.adjust_size( x );
- double dt = 0.1;
- size_t steps = integrate_adaptive( stepper , lorenz() , x , 0.0 , 10.0 , dt );
- std::cout << "required steps: " << steps << std::endl;
- }
- BOOST_AUTO_TEST_SUITE_END()
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