/* [auto_generated] boost/numeric/odeint/stepper/dense_output_runge_kutta.hpp [begin_description] Implementation of the Dense-output stepper for all steppers. Note, that this class does not computes the result but serves as an interface. [end_description] Copyright 2011-2013 Karsten Ahnert Copyright 2011-2015 Mario Mulansky Copyright 2012 Christoph Koke 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) */ #ifndef BOOST_NUMERIC_ODEINT_STEPPER_DENSE_OUTPUT_RUNGE_KUTTA_HPP_INCLUDED #define BOOST_NUMERIC_ODEINT_STEPPER_DENSE_OUTPUT_RUNGE_KUTTA_HPP_INCLUDED #include #include #include #include #include #include #include #include #include #include #include namespace boost { namespace numeric { namespace odeint { template< class Stepper , class StepperCategory = typename Stepper::stepper_category > class dense_output_runge_kutta; /** * \brief The class representing dense-output Runge-Kutta steppers. * \note In this stepper, the initialize method has to be called before using * the do_step method. * * The dense-output functionality allows to interpolate the solution between * subsequent integration points using intermediate results obtained during the * computation. This version works based on a normal stepper without step-size * control. * * * \tparam Stepper The stepper type of the underlying algorithm. */ template< class Stepper > class dense_output_runge_kutta< Stepper , stepper_tag > { public: /* * We do not need all typedefs. */ typedef Stepper stepper_type; typedef typename stepper_type::state_type state_type; typedef typename stepper_type::wrapped_state_type wrapped_state_type; typedef typename stepper_type::value_type value_type; typedef typename stepper_type::deriv_type deriv_type; typedef typename stepper_type::wrapped_deriv_type wrapped_deriv_type; typedef typename stepper_type::time_type time_type; typedef typename stepper_type::algebra_type algebra_type; typedef typename stepper_type::operations_type operations_type; typedef typename stepper_type::resizer_type resizer_type; typedef dense_output_stepper_tag stepper_category; typedef dense_output_runge_kutta< Stepper > dense_output_stepper_type; /** * \brief Constructs the dense_output_runge_kutta class. An instance of the * underlying stepper can be provided. * \param stepper An instance of the underlying stepper. */ dense_output_runge_kutta( const stepper_type &stepper = stepper_type() ) : m_stepper( stepper ) , m_resizer() , m_x1() , m_x2() , m_current_state_x1( true ) , m_t() , m_t_old() , m_dt() { } /** * \brief Initializes the stepper. Has to be called before do_step can be * used to set the initial conditions and the step size. * \param x0 The initial state of the ODE which should be solved. * \param t0 The initial time, at which the step should be performed. * \param dt0 The step size. */ template< class StateType > void initialize( const StateType &x0 , time_type t0 , time_type dt0 ) { m_resizer.adjust_size( x0 , detail::bind( &dense_output_stepper_type::template resize_impl< StateType > , detail::ref( *this ) , detail::_1 ) ); boost::numeric::odeint::copy( x0 , get_current_state() ); m_t = t0; m_dt = dt0; } /** * \brief Does one time step. * \note initialize has to be called before using this method to set the * initial conditions x,t and the stepsize. * \param system The system function to solve, hence the r.h.s. of the ordinary differential equation. It must fulfill the * Simple System concept. * \return Pair with start and end time of the integration step. */ template< class System > std::pair< time_type , time_type > do_step( System system ) { m_stepper.do_step( system , get_current_state() , m_t , get_old_state() , m_dt ); m_t_old = m_t; m_t += m_dt; toggle_current_state(); return std::make_pair( m_t_old , m_dt ); } /* * The next two overloads are needed to solve the forwarding problem */ /** * \brief Calculates the solution at an intermediate point. * \param t The time at which the solution should be calculated, has to be * in the current time interval. * \param x The output variable where the result is written into. */ template< class StateOut > void calc_state( time_type t , StateOut &x ) const { if( t == current_time() ) { boost::numeric::odeint::copy( get_current_state() , x ); } m_stepper.calc_state( x , t , get_old_state() , m_t_old , get_current_state() , m_t ); } /** * \brief Calculates the solution at an intermediate point. Solves the forwarding problem * \param t The time at which the solution should be calculated, has to be * in the current time interval. * \param x The output variable where the result is written into, can be a boost range. */ template< class StateOut > void calc_state( time_type t , const StateOut &x ) const { m_stepper.calc_state( x , t , get_old_state() , m_t_old , get_current_state() , m_t ); } /** * \brief Adjust the size of all temporaries in the stepper manually. * \param x A state from which the size of the temporaries to be resized is deduced. */ template< class StateType > void adjust_size( const StateType &x ) { resize_impl( x ); m_stepper.stepper().resize( x ); } /** * \brief Returns the current state of the solution. * \return The current state of the solution x(t). */ const state_type& current_state( void ) const { return get_current_state(); } /** * \brief Returns the current time of the solution. * \return The current time of the solution t. */ time_type current_time( void ) const { return m_t; } /** * \brief Returns the last state of the solution. * \return The last state of the solution x(t-dt). */ const state_type& previous_state( void ) const { return get_old_state(); } /** * \brief Returns the last time of the solution. * \return The last time of the solution t-dt. */ time_type previous_time( void ) const { return m_t_old; } /** * \brief Returns the current time step. * \return dt. */ time_type current_time_step( void ) const { return m_dt; } private: state_type& get_current_state( void ) { return m_current_state_x1 ? m_x1.m_v : m_x2.m_v ; } const state_type& get_current_state( void ) const { return m_current_state_x1 ? m_x1.m_v : m_x2.m_v ; } state_type& get_old_state( void ) { return m_current_state_x1 ? m_x2.m_v : m_x1.m_v ; } const state_type& get_old_state( void ) const { return m_current_state_x1 ? m_x2.m_v : m_x1.m_v ; } void toggle_current_state( void ) { m_current_state_x1 = ! m_current_state_x1; } template< class StateIn > bool resize_impl( const StateIn &x ) { bool resized = false; resized |= adjust_size_by_resizeability( m_x1 , x , typename is_resizeable::type() ); resized |= adjust_size_by_resizeability( m_x2 , x , typename is_resizeable::type() ); return resized; } stepper_type m_stepper; resizer_type m_resizer; wrapped_state_type m_x1 , m_x2; bool m_current_state_x1; // if true, the current state is m_x1 time_type m_t , m_t_old , m_dt; }; /** * \brief The class representing dense-output Runge-Kutta steppers with FSAL property. * * The interface is the same as for dense_output_runge_kutta< Stepper , stepper_tag >. * This class provides dense output functionality based on methods with step size controlled * * * \tparam Stepper The stepper type of the underlying algorithm. */ template< class Stepper > class dense_output_runge_kutta< Stepper , explicit_controlled_stepper_fsal_tag > { public: /* * We do not need all typedefs. */ typedef Stepper controlled_stepper_type; typedef typename controlled_stepper_type::stepper_type stepper_type; typedef typename stepper_type::state_type state_type; typedef typename stepper_type::wrapped_state_type wrapped_state_type; typedef typename stepper_type::value_type value_type; typedef typename stepper_type::deriv_type deriv_type; typedef typename stepper_type::wrapped_deriv_type wrapped_deriv_type; typedef typename stepper_type::time_type time_type; typedef typename stepper_type::algebra_type algebra_type; typedef typename stepper_type::operations_type operations_type; typedef typename stepper_type::resizer_type resizer_type; typedef dense_output_stepper_tag stepper_category; typedef dense_output_runge_kutta< Stepper > dense_output_stepper_type; dense_output_runge_kutta( const controlled_stepper_type &stepper = controlled_stepper_type() ) : m_stepper( stepper ) , m_resizer() , m_current_state_x1( true ) , m_x1() , m_x2() , m_dxdt1() , m_dxdt2() , m_t() , m_t_old() , m_dt() , m_is_deriv_initialized( false ) { } template< class StateType > void initialize( const StateType &x0 , time_type t0 , time_type dt0 ) { m_resizer.adjust_size( x0 , detail::bind( &dense_output_stepper_type::template resize< StateType > , detail::ref( *this ) , detail::_1 ) ); boost::numeric::odeint::copy( x0 , get_current_state() ); m_t = t0; m_dt = dt0; m_is_deriv_initialized = false; } template< class System > std::pair< time_type , time_type > do_step( System system ) { if( !m_is_deriv_initialized ) { typename odeint::unwrap_reference< System >::type &sys = system; sys( get_current_state() , get_current_deriv() , m_t ); m_is_deriv_initialized = true; } failed_step_checker fail_checker; // to throw a runtime_error if step size adjustment fails controlled_step_result res = fail; m_t_old = m_t; do { res = m_stepper.try_step( system , get_current_state() , get_current_deriv() , m_t , get_old_state() , get_old_deriv() , m_dt ); fail_checker(); // check for overflow of failed steps } while( res == fail ); toggle_current_state(); return std::make_pair( m_t_old , m_t ); } /* * The two overloads are needed in order to solve the forwarding problem. */ template< class StateOut > void calc_state( time_type t , StateOut &x ) const { m_stepper.stepper().calc_state( t , x , get_old_state() , get_old_deriv() , m_t_old , get_current_state() , get_current_deriv() , m_t ); } template< class StateOut > void calc_state( time_type t , const StateOut &x ) const { m_stepper.stepper().calc_state( t , x , get_old_state() , get_old_deriv() , m_t_old , get_current_state() , get_current_deriv() , m_t ); } template< class StateIn > bool resize( const StateIn &x ) { bool resized = false; resized |= adjust_size_by_resizeability( m_x1 , x , typename is_resizeable::type() ); resized |= adjust_size_by_resizeability( m_x2 , x , typename is_resizeable::type() ); resized |= adjust_size_by_resizeability( m_dxdt1 , x , typename is_resizeable::type() ); resized |= adjust_size_by_resizeability( m_dxdt2 , x , typename is_resizeable::type() ); return resized; } template< class StateType > void adjust_size( const StateType &x ) { resize( x ); m_stepper.stepper().resize( x ); } const state_type& current_state( void ) const { return get_current_state(); } time_type current_time( void ) const { return m_t; } const state_type& previous_state( void ) const { return get_old_state(); } time_type previous_time( void ) const { return m_t_old; } time_type current_time_step( void ) const { return m_dt; } private: state_type& get_current_state( void ) { return m_current_state_x1 ? m_x1.m_v : m_x2.m_v ; } const state_type& get_current_state( void ) const { return m_current_state_x1 ? m_x1.m_v : m_x2.m_v ; } state_type& get_old_state( void ) { return m_current_state_x1 ? m_x2.m_v : m_x1.m_v ; } const state_type& get_old_state( void ) const { return m_current_state_x1 ? m_x2.m_v : m_x1.m_v ; } deriv_type& get_current_deriv( void ) { return m_current_state_x1 ? m_dxdt1.m_v : m_dxdt2.m_v ; } const deriv_type& get_current_deriv( void ) const { return m_current_state_x1 ? m_dxdt1.m_v : m_dxdt2.m_v ; } deriv_type& get_old_deriv( void ) { return m_current_state_x1 ? m_dxdt2.m_v : m_dxdt1.m_v ; } const deriv_type& get_old_deriv( void ) const { return m_current_state_x1 ? m_dxdt2.m_v : m_dxdt1.m_v ; } void toggle_current_state( void ) { m_current_state_x1 = ! m_current_state_x1; } controlled_stepper_type m_stepper; resizer_type m_resizer; bool m_current_state_x1; wrapped_state_type m_x1 , m_x2; wrapped_deriv_type m_dxdt1 , m_dxdt2; time_type m_t , m_t_old , m_dt; bool m_is_deriv_initialized; }; } // namespace odeint } // namespace numeric } // namespace boost #endif // BOOST_NUMERIC_ODEINT_STEPPER_DENSE_OUTPUT_RUNGE_KUTTA_HPP_INCLUDED