boost/numeric/odeint/stepper/adams_bashforth.hpp
/* [auto_generated] boost/numeric/odeint/stepper/adams_bashforth.hpp [begin_description] Implementaton of the Adam-Bashforth method a multistep method used for the predictor step in the Adams-Bashforth-Moulton method. [end_description] Copyright 2011-2013 Karsten Ahnert Copyright 2011-2013 Mario Mulansky Copyright 2012 Christoph Koke Copyright 2013 Pascal Germroth 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_ADAMS_BASHFORTH_HPP_INCLUDED #define BOOST_NUMERIC_ODEINT_STEPPER_ADAMS_BASHFORTH_HPP_INCLUDED #include <boost/static_assert.hpp> #include <boost/numeric/odeint/util/bind.hpp> #include <boost/numeric/odeint/util/unwrap_reference.hpp> #include <boost/numeric/odeint/algebra/range_algebra.hpp> #include <boost/numeric/odeint/algebra/default_operations.hpp> #include <boost/numeric/odeint/algebra/algebra_dispatcher.hpp> #include <boost/numeric/odeint/algebra/operations_dispatcher.hpp> #include <boost/numeric/odeint/util/state_wrapper.hpp> #include <boost/numeric/odeint/util/is_resizeable.hpp> #include <boost/numeric/odeint/util/resizer.hpp> #include <boost/numeric/odeint/stepper/stepper_categories.hpp> #include <boost/numeric/odeint/stepper/runge_kutta4.hpp> #include <boost/numeric/odeint/stepper/extrapolation_stepper.hpp> #include <boost/numeric/odeint/stepper/base/algebra_stepper_base.hpp> #include <boost/numeric/odeint/stepper/detail/adams_bashforth_coefficients.hpp> #include <boost/numeric/odeint/stepper/detail/adams_bashforth_call_algebra.hpp> #include <boost/numeric/odeint/stepper/detail/rotating_buffer.hpp> #include <boost/mpl/arithmetic.hpp> #include <boost/mpl/min_max.hpp> #include <boost/mpl/equal_to.hpp> namespace mpl = boost::mpl; namespace boost { namespace numeric { namespace odeint { using mpl::int_; /* if N >= 4, returns the smallest even number > N, otherwise returns 4 */ template < int N > struct order_helper : mpl::max< typename mpl::eval_if< mpl::equal_to< mpl::modulus< int_< N >, int_< 2 > >, int_< 0 > >, int_< N >, int_< N + 1 > >::type, int_< 4 > >::type { }; template< size_t Steps , class State , class Value = double , class Deriv = State , class Time = Value , class Algebra = typename algebra_dispatcher< State >::algebra_type , class Operations = typename operations_dispatcher< State >::operations_type , class Resizer = initially_resizer , class InitializingStepper = extrapolation_stepper< order_helper<Steps>::value, State, Value, Deriv, Time, Algebra, Operations, Resizer > > class adams_bashforth : public algebra_stepper_base< Algebra , Operations > { #ifndef DOXYGEN_SKIP BOOST_STATIC_ASSERT(( Steps > 0 )); BOOST_STATIC_ASSERT(( Steps < 9 )); #endif public : typedef State state_type; typedef state_wrapper< state_type > wrapped_state_type; typedef Value value_type; typedef Deriv deriv_type; typedef state_wrapper< deriv_type > wrapped_deriv_type; typedef Time time_type; typedef Resizer resizer_type; typedef stepper_tag stepper_category; typedef InitializingStepper initializing_stepper_type; typedef algebra_stepper_base< Algebra , Operations > algebra_stepper_base_type; typedef typename algebra_stepper_base_type::algebra_type algebra_type; typedef typename algebra_stepper_base_type::operations_type operations_type; #ifndef DOXYGEN_SKIP typedef adams_bashforth< Steps , State , Value , Deriv , Time , Algebra , Operations , Resizer , InitializingStepper > stepper_type; #endif static const size_t steps = Steps; typedef unsigned short order_type; static const order_type order_value = steps; typedef detail::rotating_buffer< wrapped_deriv_type , steps > step_storage_type; order_type order( void ) const { return order_value; } adams_bashforth( const algebra_type &algebra = algebra_type() ) : algebra_stepper_base_type( algebra ) , m_step_storage() , m_resizer() , m_coefficients() , m_steps_initialized( 0 ) , m_initializing_stepper() { } /* * Version 1 : do_step( system , x , t , dt ); * * solves the forwarding problem */ template< class System , class StateInOut > void do_step( System system , StateInOut &x , time_type t , time_type dt ) { do_step( system , x , t , x , dt ); } /** * \brief Second version to solve the forwarding problem, can be called with Boost.Range as StateInOut. */ template< class System , class StateInOut > void do_step( System system , const StateInOut &x , time_type t , time_type dt ) { do_step( system , x , t , x , dt ); } /* * Version 2 : do_step( system , in , t , out , dt ); * * solves the forwarding problem */ template< class System , class StateIn , class StateOut > void do_step( System system , const StateIn &in , time_type t , StateOut &out , time_type dt ) { do_step_impl( system , in , t , out , dt ); } /** * \brief Second version to solve the forwarding problem, can be called with Boost.Range as StateOut. */ template< class System , class StateIn , class StateOut > void do_step( System system , const StateIn &in , time_type t , const StateOut &out , time_type dt ) { do_step_impl( system , in , t , out , dt ); } template< class StateType > void adjust_size( const StateType &x ) { resize_impl( x ); } const step_storage_type& step_storage( void ) const { return m_step_storage; } step_storage_type& step_storage( void ) { return m_step_storage; } template< class ExplicitStepper , class System , class StateIn > void initialize( ExplicitStepper explicit_stepper , System system , StateIn &x , time_type &t , time_type dt ) { typename odeint::unwrap_reference< ExplicitStepper >::type &stepper = explicit_stepper; typename odeint::unwrap_reference< System >::type &sys = system; m_resizer.adjust_size( x , detail::bind( &stepper_type::template resize_impl<StateIn> , detail::ref( *this ) , detail::_1 ) ); for( size_t i=0 ; i+1<steps ; ++i ) { if( i != 0 ) m_step_storage.rotate(); sys( x , m_step_storage[0].m_v , t ); stepper.do_step_dxdt_impl( system, x, m_step_storage[0].m_v, t, dt ); t += dt; } m_steps_initialized = steps; } template< class System , class StateIn > void initialize( System system , StateIn &x , time_type &t , time_type dt ) { initialize( detail::ref( m_initializing_stepper ) , system , x , t , dt ); } void reset( void ) { m_steps_initialized = 0; } bool is_initialized( void ) const { return m_steps_initialized >= ( steps - 1 ); } const initializing_stepper_type& initializing_stepper( void ) const { return m_initializing_stepper; } initializing_stepper_type& initializing_stepper( void ) { return m_initializing_stepper; } private: template< class System , class StateIn , class StateOut > void do_step_impl( System system , const StateIn &in , time_type t , StateOut &out , time_type dt ) { typename odeint::unwrap_reference< System >::type &sys = system; if( m_resizer.adjust_size( in , detail::bind( &stepper_type::template resize_impl<StateIn> , detail::ref( *this ) , detail::_1 ) ) ) { m_steps_initialized = 0; } if( m_steps_initialized + 1 < steps ) { if( m_steps_initialized != 0 ) m_step_storage.rotate(); sys( in , m_step_storage[0].m_v , t ); m_initializing_stepper.do_step_dxdt_impl( system, in, m_step_storage[0].m_v, t, out, dt ); ++m_steps_initialized; } else { m_step_storage.rotate(); sys( in , m_step_storage[0].m_v , t ); detail::adams_bashforth_call_algebra< steps , algebra_type , operations_type >()( this->m_algebra , in , out , m_step_storage , m_coefficients , dt ); } } template< class StateIn > bool resize_impl( const StateIn &x ) { bool resized( false ); for( size_t i=0 ; i<steps ; ++i ) { resized |= adjust_size_by_resizeability( m_step_storage[i] , x , typename is_resizeable<deriv_type>::type() ); } return resized; } step_storage_type m_step_storage; resizer_type m_resizer; detail::adams_bashforth_coefficients< value_type , steps > m_coefficients; size_t m_steps_initialized; initializing_stepper_type m_initializing_stepper; }; /***** DOXYGEN *****/ /** * \class adams_bashforth * \brief The Adams-Bashforth multistep algorithm. * * The Adams-Bashforth method is a multi-step algorithm with configurable step * number. The step number is specified as template parameter Steps and it * then uses the result from the previous Steps steps. See also * <a href="http://en.wikipedia.org/wiki/Linear_multistep_method">en.wikipedia.org/wiki/Linear_multistep_method</a>. * Currently, a maximum of Steps=8 is supported. * The method is explicit and fulfills the Stepper concept. Step size control * or continuous output are not provided. * * This class derives from algebra_base and inherits its interface via * CRTP (current recurring template pattern). For more details see * algebra_stepper_base. * * \tparam Steps The number of steps (maximal 8). * \tparam State The state type. * \tparam Value The value type. * \tparam Deriv The type representing the time derivative of the state. * \tparam Time The time representing the independent variable - the time. * \tparam Algebra The algebra type. * \tparam Operations The operations type. * \tparam Resizer The resizer policy type. * \tparam InitializingStepper The stepper for the first two steps. */ /** * \fn adams_bashforth::adams_bashforth( const algebra_type &algebra ) * \brief Constructs the adams_bashforth class. This constructor can be used as a default * constructor if the algebra has a default constructor. * \param algebra A copy of algebra is made and stored. */ /** * \fn order_type adams_bashforth::order( void ) const * \brief Returns the order of the algorithm, which is equal to the number of steps. * \return order of the method. */ /** * \fn void adams_bashforth::do_step( System system , StateInOut &x , time_type t , time_type dt ) * \brief This method performs one step. It transforms the result in-place. * * \param system The system function to solve, hence the r.h.s. of the ordinary differential equation. It must fulfill the * Simple System concept. * \param x The state of the ODE which should be solved. After calling do_step the result is updated in x. * \param t The value of the time, at which the step should be performed. * \param dt The step size. */ /** * \fn void adams_bashforth::do_step( System system , const StateIn &in , time_type t , StateOut &out , time_type dt ) * \brief The method performs one step with the stepper passed by Stepper. The state of the ODE is updated out-of-place. * * \param system The system function to solve, hence the r.h.s. of the ODE. It must fulfill the * Simple System concept. * \param in The state of the ODE which should be solved. in is not modified in this method * \param t The value of the time, at which the step should be performed. * \param out The result of the step is written in out. * \param dt The step size. */ /** * \fn void adams_bashforth::adjust_size( const StateType &x ) * \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. */ /** * \fn const step_storage_type& adams_bashforth::step_storage( void ) const * \brief Returns the storage of intermediate results. * \return The storage of intermediate results. */ /** * \fn step_storage_type& adams_bashforth::step_storage( void ) * \brief Returns the storage of intermediate results. * \return The storage of intermediate results. */ /** * \fn void adams_bashforth::initialize( ExplicitStepper explicit_stepper , System system , StateIn &x , time_type &t , time_type dt ) * \brief Initialized the stepper. Does Steps-1 steps with the explicit_stepper to fill the buffer. * \param explicit_stepper the stepper used to fill the buffer of previous step results * \param system The system function to solve, hence the r.h.s. of the ordinary differential equation. It must fulfill the * Simple System concept. * \param x The state of the ODE which should be solved. After calling do_step the result is updated in x. * \param t The value of the time, at which the step should be performed. * \param dt The step size. */ /** * \fn void adams_bashforth::initialize( System system , StateIn &x , time_type &t , time_type dt ) * \brief Initialized the stepper. Does Steps-1 steps with an internal instance of InitializingStepper to fill the buffer. * \note The state x and time t are updated to the values after Steps-1 initial steps. * \param system The system function to solve, hence the r.h.s. of the ordinary differential equation. It must fulfill the * Simple System concept. * \param x The initial state of the ODE which should be solved, updated in this method. * \param t The initial value of the time, updated in this method. * \param dt The step size. */ /** * \fn void adams_bashforth::reset( void ) * \brief Resets the internal buffer of the stepper. */ /** * \fn bool adams_bashforth::is_initialized( void ) const * \brief Returns true if the stepper has been initialized. * \return bool true if stepper is initialized, false otherwise */ /** * \fn const initializing_stepper_type& adams_bashforth::initializing_stepper( void ) const * \brief Returns the internal initializing stepper instance. * \return initializing_stepper */ /** * \fn const initializing_stepper_type& adams_bashforth::initializing_stepper( void ) const * \brief Returns the internal initializing stepper instance. * \return initializing_stepper */ /** * \fn initializing_stepper_type& adams_bashforth::initializing_stepper( void ) * \brief Returns the internal initializing stepper instance. * \return initializing_stepper */ } // odeint } // numeric } // boost #endif // BOOST_NUMERIC_ODEINT_STEPPER_ADAMS_BASHFORTH_HPP_INCLUDED