boost/numeric/odeint/stepper/dense_output_runge_kutta.hpp
/*
[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 <utility>
#include <stdexcept>
#include <boost/throw_exception.hpp>
#include <boost/numeric/odeint/util/bind.hpp>
#include <boost/numeric/odeint/util/copy.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/controlled_step_result.hpp>
#include <boost/numeric/odeint/stepper/stepper_categories.hpp>
#include <boost/numeric/odeint/integrate/max_step_checker.hpp>
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, [this](auto&& arg) { return this->resize_impl<StateType>(std::forward<decltype(arg)>(arg)); });
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_t );
}
/*
* 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<state_type>::type() );
resized |= adjust_size_by_resizeability( m_x2 , x , typename is_resizeable<state_type>::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, [this](auto&& arg) { return this->resize<StateType>(std::forward<decltype(arg)>(arg)); });
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<state_type>::type() );
resized |= adjust_size_by_resizeability( m_x2 , x , typename is_resizeable<state_type>::type() );
resized |= adjust_size_by_resizeability( m_dxdt1 , x , typename is_resizeable<deriv_type>::type() );
resized |= adjust_size_by_resizeability( m_dxdt2 , x , typename is_resizeable<deriv_type>::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