416 lines
16 KiB
Plaintext
416 lines
16 KiB
Plaintext
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/*
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[auto_generated]
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boost/numeric/odeint/stepper/base/explicit_stepper_base.hpp
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[begin_description]
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Base class for all explicit Runge Kutta steppers.
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[end_description]
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Copyright 2010-2013 Karsten Ahnert
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Copyright 2010-2012 Mario Mulansky
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Copyright 2012 Christoph Koke
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Distributed under the Boost Software License, Version 1.0.
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(See accompanying file LICENSE_1_0.txt or
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copy at http://www.boost.org/LICENSE_1_0.txt)
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*/
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#ifndef BOOST_NUMERIC_ODEINT_STEPPER_BASE_EXPLICIT_STEPPER_BASE_HPP_INCLUDED
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#define BOOST_NUMERIC_ODEINT_STEPPER_BASE_EXPLICIT_STEPPER_BASE_HPP_INCLUDED
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#include <boost/utility/enable_if.hpp>
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#include <boost/type_traits/is_same.hpp>
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#include <boost/numeric/odeint/util/bind.hpp>
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#include <boost/numeric/odeint/util/unwrap_reference.hpp>
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#include <boost/numeric/odeint/util/state_wrapper.hpp>
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#include <boost/numeric/odeint/util/resizer.hpp>
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#include <boost/numeric/odeint/util/is_resizeable.hpp>
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#include <boost/numeric/odeint/stepper/stepper_categories.hpp>
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#include <boost/numeric/odeint/stepper/base/algebra_stepper_base.hpp>
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namespace boost {
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namespace numeric {
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namespace odeint {
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/*
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* base class for explicit steppers
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* models the stepper concept
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*
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* this class provides the following overloads
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* do_step( sys , x , t , dt )
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* do_step( sys , in , t , out , dt )
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* do_step( sys , x , dxdt_in , t , dt )
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* do_step( sys , in , dxdt_in , t , out , dt )
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*/
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template<
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class Stepper ,
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unsigned short Order ,
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class State ,
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class Value ,
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class Deriv ,
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class Time ,
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class Algebra ,
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class Operations ,
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class Resizer
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>
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class explicit_stepper_base : public algebra_stepper_base< Algebra , Operations >
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{
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public:
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#ifndef DOXYGEN_SKIP
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typedef explicit_stepper_base< Stepper , Order , State , Value , Deriv , Time , Algebra , Operations , Resizer > internal_stepper_base_type;
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#endif // DOXYGEN_SKIP
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typedef State state_type;
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typedef Value value_type;
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typedef Deriv deriv_type;
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typedef Time time_type;
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typedef Resizer resizer_type;
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typedef Stepper stepper_type;
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typedef stepper_tag stepper_category;
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typedef algebra_stepper_base< Algebra , Operations > algebra_stepper_base_type;
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typedef typename algebra_stepper_base_type::algebra_type algebra_type;
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typedef typename algebra_stepper_base_type::operations_type operations_type;
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typedef unsigned short order_type;
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#ifndef DOXYGEN_SKIP
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typedef state_wrapper< state_type > wrapped_state_type;
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typedef state_wrapper< deriv_type > wrapped_deriv_type;
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#endif // DOXYGEN_SKIP
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static const order_type order_value = Order;
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explicit_stepper_base( const algebra_type &algebra = algebra_type() )
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: algebra_stepper_base_type( algebra )
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{ }
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/**
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* \return Returns the order of the stepper.
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*/
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order_type order( void ) const
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{
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return order_value;
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}
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/*
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* Version 1 : do_step( sys , x , t , dt )
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*
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* the two overloads are needed in order to solve the forwarding problem
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*/
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template< class System , class StateInOut >
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void do_step( System system , StateInOut &x , time_type t , time_type dt )
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{
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do_step_v1( system , x , t , dt );
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}
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/**
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* \brief Second version to solve the forwarding problem, can be called with Boost.Range as StateInOut.
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*/
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template< class System , class StateInOut >
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void do_step( System system , const StateInOut &x , time_type t , time_type dt )
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{
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do_step_v1( system , x , t , dt );
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}
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/*
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* Version 2 : do_step( sys , x , dxdt , t , dt )
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*
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* this version does not solve the forwarding problem, boost.range can not be used
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*
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* the disable is needed to avoid ambiguous overloads if state_type = time_type
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*/
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template< class System , class StateInOut , class DerivIn >
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typename boost::disable_if< boost::is_same< DerivIn , time_type > , void >::type
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do_step( System system , StateInOut &x , const DerivIn &dxdt , time_type t , time_type dt )
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{
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this->stepper().do_step_impl( system , x , dxdt , t , x , dt );
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}
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/*
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* named Version 2: do_step_dxdt_impl( sys , in , dxdt , t , dt )
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*
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* this version is needed when this stepper is used for initializing
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* multistep stepper like adams-bashforth. Hence we provide an explicitely
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* named version that is not disabled. Meant for internal use only.
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*/
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template < class System, class StateInOut, class DerivIn >
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void do_step_dxdt_impl( System system, StateInOut &x, const DerivIn &dxdt,
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time_type t, time_type dt )
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{
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this->stepper().do_step_impl( system , x , dxdt , t , x , dt );
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}
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/*
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* Version 3 : do_step( sys , in , t , out , dt )
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*
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* this version does not solve the forwarding problem, boost.range can not be used
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*/
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template< class System , class StateIn , class StateOut >
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void do_step( System system , const StateIn &in , time_type t , StateOut &out , time_type dt )
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{
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typename odeint::unwrap_reference< System >::type &sys = system;
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m_resizer.adjust_size( in , detail::bind( &internal_stepper_base_type::template resize_impl<StateIn> , detail::ref( *this ) , detail::_1 ) );
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sys( in , m_dxdt.m_v ,t );
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this->stepper().do_step_impl( system , in , m_dxdt.m_v , t , out , dt );
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}
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/*
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* Version 4 : do_step( sys , in , dxdt , t , out , dt )
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*
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* this version does not solve the forwarding problem, boost.range can not be used
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*/
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template< class System , class StateIn , class DerivIn , class StateOut >
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void do_step( System system , const StateIn &in , const DerivIn &dxdt , time_type t , StateOut &out , time_type dt )
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{
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this->stepper().do_step_impl( system , in , dxdt , t , out , dt );
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}
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/*
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* named Version 4: do_step_dxdt_impl( sys , in , dxdt , t , out, dt )
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*
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* this version is needed when this stepper is used for initializing
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* multistep stepper like adams-bashforth. Hence we provide an explicitely
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* named version. Meant for internal use only.
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*/
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template < class System, class StateIn, class DerivIn, class StateOut >
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void do_step_dxdt_impl( System system, const StateIn &in,
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const DerivIn &dxdt, time_type t, StateOut &out,
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time_type dt )
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{
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this->stepper().do_step_impl( system , in , dxdt , t , out , dt );
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}
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template< class StateIn >
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void adjust_size( const StateIn &x )
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{
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resize_impl( x );
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}
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private:
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stepper_type& stepper( void )
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{
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return *static_cast< stepper_type* >( this );
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}
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const stepper_type& stepper( void ) const
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{
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return *static_cast< const stepper_type* >( this );
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}
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template< class StateIn >
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bool resize_impl( const StateIn &x )
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{
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return adjust_size_by_resizeability( m_dxdt , x , typename is_resizeable<deriv_type>::type() );
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}
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template< class System , class StateInOut >
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void do_step_v1( System system , StateInOut &x , time_type t , time_type dt )
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{
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typename odeint::unwrap_reference< System >::type &sys = system;
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m_resizer.adjust_size( x , detail::bind( &internal_stepper_base_type::template resize_impl< StateInOut > , detail::ref( *this ) , detail::_1 ) );
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sys( x , m_dxdt.m_v ,t );
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this->stepper().do_step_impl( system , x , m_dxdt.m_v , t , x , dt );
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}
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resizer_type m_resizer;
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protected:
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wrapped_deriv_type m_dxdt;
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};
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/******* DOXYGEN *********/
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/**
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* \class explicit_stepper_base
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* \brief Base class for explicit steppers without step size control and without dense output.
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*
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* This class serves as the base class for all explicit steppers with algebra and operations.
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* Step size control and error estimation as well as dense output are not provided. explicit_stepper_base
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* is used as the interface in a CRTP (currently recurring template pattern). In order to work
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* correctly the parent class needs to have a method `do_step_impl( system , in , dxdt_in , t , out , dt )`.
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* This is method is used by explicit_stepper_base. explicit_stepper_base derives from
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* algebra_stepper_base. An example how this class can be used is
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*
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* \code
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* template< class State , class Value , class Deriv , class Time , class Algebra , class Operations , class Resizer >
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* class custom_euler : public explicit_stepper_base< 1 , State , Value , Deriv , Time , Algebra , Operations , Resizer >
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* {
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* public:
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*
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* typedef explicit_stepper_base< 1 , State , Value , Deriv , Time , Algebra , Operations , Resizer > base_type;
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*
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* custom_euler( const Algebra &algebra = Algebra() ) { }
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*
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* template< class Sys , class StateIn , class DerivIn , class StateOut >
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* void do_step_impl( Sys sys , const StateIn &in , const DerivIn &dxdt , Time t , StateOut &out , Time dt )
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* {
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* m_algebra.for_each3( out , in , dxdt , Operations::scale_sum2< Value , Time >( 1.0 , dt );
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* }
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*
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* template< class State >
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* void adjust_size( const State &x )
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* {
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* base_type::adjust_size( x );
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* }
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* };
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* \endcode
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*
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* For the Stepper concept only the `do_step( sys , x , t , dt )` needs to be implemented. But this class
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* provides additional `do_step` variants since the stepper is explicit. These methods can be used to increase
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* the performance in some situation, for example if one needs to analyze `dxdt` during each step. In this case
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* one can use
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*
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* \code
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* sys( x , dxdt , t );
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* stepper.do_step( sys , x , dxdt , t , dt ); // the value of dxdt is used here
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* t += dt;
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* \endcode
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*
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* In detail explicit_stepper_base provides the following `do_step` variants
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* - `do_step( sys , x , t , dt )` - The classical `do_step` method needed to fulfill the Stepper concept. The state is updated in-place.
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* A type modelling a Boost.Range can be used for x.
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* - `do_step( sys , in , t , out , dt )` - This method updates the state out-of-place, hence the result of the step is stored in `out`.
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* - `do_step( sys , x , dxdt , t , dt )` - This method updates the state in-place, but the derivative at the point `t` must be
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* explicitly passed in `dxdt`. For an example see the code snippet above.
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* - `do_step( sys , in , dxdt , t , out , dt )` - This method update the state out-of-place and expects that the derivative at the point
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* `t` is explicitly passed in `dxdt`. It is a combination of the two `do_step` methods above.
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*
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* \note The system is always passed as value, which might result in poor performance if it contains data. In this case it can be used with `boost::ref`
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* or `std::ref`, for example `stepper.do_step( boost::ref( sys ) , x , t , dt );`
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*
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* \note The time `t` is not advanced by the stepper. This has to done manually, or by the appropriate `integrate` routines or `iterator`s.
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*
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* \tparam Stepper The stepper on which this class should work. It is used via CRTP, hence explicit_stepper_base
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* provides the interface for the Stepper.
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* \tparam Order The order of the stepper.
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* \tparam State The state type for the stepper.
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* \tparam Value The value type for the stepper. This should be a floating point type, like float,
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* double, or a multiprecision type. It must not necessary be the value_type of the State. For example
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* the State can be a `vector< complex< double > >` in this case the Value must be double.
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* The default value is double.
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* \tparam Deriv The type representing time derivatives of the state type. It is usually the same type as the
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* state type, only if used with Boost.Units both types differ.
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* \tparam Time The type representing the time. Usually the same type as the value type. When Boost.Units is
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* used, this type has usually a unit.
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* \tparam Algebra The algebra type which must fulfill the Algebra Concept.
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* \tparam Operations The type for the operations which must fulfill the Operations Concept.
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* \tparam Resizer The resizer policy class.
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*/
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/**
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* \fn explicit_stepper_base::explicit_stepper_base( const algebra_type &algebra )
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* \brief Constructs a explicit_stepper_base class. This constructor can be used as a default
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* constructor if the algebra has a default constructor.
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* \param algebra A copy of algebra is made and stored inside explicit_stepper_base.
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*/
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/**
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* \fn explicit_stepper_base::order_type order( void ) const
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* \return Returns the order of the stepper.
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*/
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/**
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* \fn explicit_stepper_base::do_step( System system , StateInOut &x , time_type t , time_type dt )
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* \brief This method performs one step. It transforms the result in-place.
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*
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* \param system The system function to solve, hence the r.h.s. of the ordinary differential equation. It must fulfill the
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* Simple System concept.
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* \param x The state of the ODE which should be solved. After calling do_step the result is updated in x.
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* \param t The value of the time, at which the step should be performed.
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* \param dt The step size.
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*/
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/**
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* \fn explicit_stepper_base::do_step( System system , StateInOut &x , const DerivIn &dxdt , time_type t , time_type dt )
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* \brief The method performs one step. Additionally to the other method
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* the derivative of x is also passed to this method. It is supposed to be used in the following way:
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*
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* \code
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* sys( x , dxdt , t );
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* stepper.do_step( sys , x , dxdt , t , dt );
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* \endcode
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*
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* The result is updated in place in x. This method is disabled if Time and Deriv are of the same type. In this
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* case the method could not be distinguished from other `do_step` versions.
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*
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* \note This method does not solve the forwarding problem.
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*
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* \param system The system function to solve, hence the r.h.s. of the ODE. It must fulfill the
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* Simple System concept.
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* \param x The state of the ODE which should be solved. After calling do_step the result is updated in x.
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* \param dxdt The derivative of x at t.
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* \param t The value of the time, at which the step should be performed.
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* \param dt The step size.
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*/
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/**
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* \fn void explicit_stepper_base::do_step( System system , const StateIn &in , time_type t , StateOut &out , time_type dt )
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* \brief The method performs one step. The state of the ODE is updated out-of-place.
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* \note This method does not solve the forwarding problem.
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*
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* \param system The system function to solve, hence the r.h.s. of the ODE. It must fulfill the
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* Simple System concept.
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* \param in The state of the ODE which should be solved. in is not modified in this method
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* \param t The value of the time, at which the step should be performed.
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* \param out The result of the step is written in out.
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* \param dt The step size.
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*/
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/**
|
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* \fn void explicit_stepper_base::do_step( System system , const StateIn &in , const DerivIn &dxdt , time_type t , StateOut &out , time_type dt )
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* \brief The method performs one step. The state of the ODE is updated out-of-place.
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* Furthermore, the derivative of x at t is passed to the stepper.
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* It is supposed to be used in the following way:
|
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*
|
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* \code
|
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* sys( in , dxdt , t );
|
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* stepper.do_step( sys , in , dxdt , t , out , dt );
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* \endcode
|
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*
|
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* \note This method does not solve the forwarding problem.
|
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*
|
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* \param system The system function to solve, hence the r.h.s. of the ODE. It must fulfill the
|
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|
|
* Simple System concept.
|
||
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* \param in The state of the ODE which should be solved. in is not modified in this method
|
||
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* \param dxdt The derivative of x at t.
|
||
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|
* \param t The value of the time, at which the step should be performed.
|
||
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* \param out The result of the step is written in out.
|
||
|
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* \param dt The step size.
|
||
|
|
*/
|
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|
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/**
|
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|
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* \fn void explicit_stepper_base::adjust_size( const StateIn &x )
|
||
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* \brief Adjust the size of all temporaries in the stepper manually.
|
||
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* \param x A state from which the size of the temporaries to be resized is deduced.
|
||
|
|
*/
|
||
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|
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|
|
} // odeint
|
||
|
|
} // numeric
|
||
|
|
} // boost
|
||
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|
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|
|
#endif // BOOST_NUMERIC_ODEINT_STEPPER_BASE_EXPLICIT_STEPPER_BASE_HPP_INCLUDED
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