mirror of
https://github.com/ecency/ecency-mobile.git
synced 2024-12-23 13:22:02 +03:00
167 lines
6.6 KiB
C++
167 lines
6.6 KiB
C++
/*
|
|
[auto_generated]
|
|
boost/numeric/odeint/stepper/euler.hpp
|
|
|
|
[begin_description]
|
|
Implementation of the classical explicit Euler stepper. This method is really simple and should only
|
|
be used for demonstration purposes.
|
|
[end_description]
|
|
|
|
Copyright 2010-2013 Karsten Ahnert
|
|
Copyright 2010-2013 Mario Mulansky
|
|
|
|
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_EULER_HPP_INCLUDED
|
|
#define BOOST_NUMERIC_ODEINT_STEPPER_EULER_HPP_INCLUDED
|
|
|
|
|
|
#include <boost/numeric/odeint/stepper/base/explicit_stepper_base.hpp>
|
|
#include <boost/numeric/odeint/util/resizer.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>
|
|
|
|
namespace boost {
|
|
namespace numeric {
|
|
namespace odeint {
|
|
|
|
|
|
template<
|
|
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
|
|
>
|
|
#ifndef DOXYGEN_SKIP
|
|
class euler
|
|
: public explicit_stepper_base<
|
|
euler< State , Value , Deriv , Time , Algebra , Operations , Resizer > ,
|
|
1 , State , Value , Deriv , Time , Algebra , Operations , Resizer >
|
|
#else
|
|
class euler : public explicit_stepper_base
|
|
#endif
|
|
{
|
|
public :
|
|
|
|
#ifndef DOXYGEN_SKIP
|
|
typedef explicit_stepper_base< euler< State , Value , Deriv , Time , Algebra , Operations , Resizer > , 1 , State , Value , Deriv , Time , Algebra , Operations , Resizer > stepper_base_type;
|
|
#else
|
|
typedef explicit_stepper_base< euler< ... > , ... > stepper_base_type;
|
|
#endif
|
|
typedef typename stepper_base_type::state_type state_type;
|
|
typedef typename stepper_base_type::value_type value_type;
|
|
typedef typename stepper_base_type::deriv_type deriv_type;
|
|
typedef typename stepper_base_type::time_type time_type;
|
|
typedef typename stepper_base_type::algebra_type algebra_type;
|
|
typedef typename stepper_base_type::operations_type operations_type;
|
|
typedef typename stepper_base_type::resizer_type resizer_type;
|
|
|
|
#ifndef DOXYGEN_SKIP
|
|
typedef typename stepper_base_type::stepper_type stepper_type;
|
|
typedef typename stepper_base_type::wrapped_state_type wrapped_state_type;
|
|
typedef typename stepper_base_type::wrapped_deriv_type wrapped_deriv_type;
|
|
#endif
|
|
|
|
|
|
euler( const algebra_type &algebra = algebra_type() ) : stepper_base_type( algebra )
|
|
{ }
|
|
|
|
template< class System , class StateIn , class DerivIn , class StateOut >
|
|
void do_step_impl( System /* system */ , const StateIn &in , const DerivIn &dxdt , time_type /* t */ , StateOut &out , time_type dt )
|
|
{
|
|
stepper_base_type::m_algebra.for_each3( out , in , dxdt ,
|
|
typename operations_type::template scale_sum2< value_type , time_type >( 1.0 , dt ) );
|
|
|
|
}
|
|
|
|
template< class StateOut , class StateIn1 , class StateIn2 >
|
|
void calc_state( StateOut &x , time_type t , const StateIn1 &old_state , time_type t_old , const StateIn2 & /*current_state*/ , time_type /* t_new */ ) const
|
|
{
|
|
const time_type delta = t - t_old;
|
|
stepper_base_type::m_algebra.for_each3( x , old_state , stepper_base_type::m_dxdt.m_v ,
|
|
typename operations_type::template scale_sum2< value_type , time_type >( 1.0 , delta ) );
|
|
}
|
|
|
|
template< class StateType >
|
|
void adjust_size( const StateType &x )
|
|
{
|
|
stepper_base_type::adjust_size( x );
|
|
}
|
|
};
|
|
|
|
|
|
|
|
/********** DOXYGEN ***********/
|
|
|
|
/**
|
|
* \class euler
|
|
* \brief An implementation of the Euler method.
|
|
*
|
|
* The Euler method is a very simply solver for ordinary differential equations. This method should not be used
|
|
* for real applications. It is only useful for demonstration purposes. Step size control is not provided but
|
|
* trivial continuous output is available.
|
|
*
|
|
* This class derives from explicit_stepper_base and inherits its interface via CRTP (current recurring template pattern),
|
|
* see explicit_stepper_base
|
|
*
|
|
* \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.
|
|
*/
|
|
|
|
/**
|
|
* \fn euler::euler( const algebra_type &algebra )
|
|
* \brief Constructs the euler class. This constructor can be used as a default
|
|
* constructor of the algebra has a default constructor.
|
|
* \param algebra A copy of algebra is made and stored inside explicit_stepper_base.
|
|
*/
|
|
|
|
/**
|
|
* \fn euler::do_step_impl( System system , const StateIn &in , const DerivIn &dxdt , time_type t , StateOut &out , time_type dt )
|
|
* \brief This method performs one step. The derivative `dxdt` of `in` at the time `t` is passed to the method.
|
|
* The result is updated out of place, hence the input is in `in` and the output in `out`.
|
|
* Access to this step functionality is provided by explicit_stepper_base and
|
|
* `do_step_impl` should not be called directly.
|
|
*
|
|
* \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 dxdt The derivative of x at t.
|
|
* \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 euler::calc_state( StateOut &x , time_type t , const StateIn1 &old_state , time_type t_old , const StateIn2 ¤t_state , time_type t_new ) const
|
|
* \brief This method is used for continuous output and it calculates the state `x` at a time `t` from the
|
|
* knowledge of two states `old_state` and `current_state` at time points `t_old` and `t_new`.
|
|
*/
|
|
|
|
/**
|
|
* \fn euler::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.
|
|
*/
|
|
|
|
} // odeint
|
|
} // numeric
|
|
} // boost
|
|
|
|
|
|
#endif // BOOST_NUMERIC_ODEINT_STEPPER_EULER_HPP_INCLUDED
|