odeint/stepper/explicit_generic_rk.hpp

0001 /*
0002  [auto_generated]
0003  boost/numeric/odeint/stepper/explicit_generic_rk.hpp
0004
0005  [begin_description]
0006  Implementation of the generic Runge-Kutta steppers. This is the base class for many Runge-Kutta steppers.
0007  [end_description]
0008
0009  Copyright 2011-2013 Mario Mulansky
0010  Copyright 2011-2013 Karsten Ahnert
0011  Copyright 2012 Christoph Koke
0012
0013  Distributed under the Boost Software License, Version 1.0.
0014  (See accompanying file LICENSE_1_0.txt or
0015  copy at http://www.boost.org/LICENSE_1_0.txt)
0016  */
0017
0018
0019 #ifndef BOOST_NUMERIC_ODEINT_STEPPER_EXPLICIT_GENERIC_RK_HPP_INCLUDED
0020 #define BOOST_NUMERIC_ODEINT_STEPPER_EXPLICIT_GENERIC_RK_HPP_INCLUDED
0021
0022
0023 #include <boost/array.hpp>
0024
0025
0026 #include <boost/numeric/odeint/stepper/base/explicit_stepper_base.hpp>
0027 #include <boost/numeric/odeint/algebra/range_algebra.hpp>
0028 #include <boost/numeric/odeint/algebra/default_operations.hpp>
0029 #include <boost/numeric/odeint/algebra/algebra_dispatcher.hpp>
0030 #include <boost/numeric/odeint/algebra/operations_dispatcher.hpp>
0031 #include <boost/numeric/odeint/stepper/detail/generic_rk_algorithm.hpp>
0032
0033 #include <boost/numeric/odeint/util/state_wrapper.hpp>
0034 #include <boost/numeric/odeint/util/is_resizeable.hpp>
0035 #include <boost/numeric/odeint/util/resizer.hpp>
0036
0037 namespace boost {
0038 namespace numeric {
0039 namespace odeint {
0040
0041 //forward declarations
0042
0043 #ifndef DOXYGEN_SKIP
0044 template<
0045 size_t StageCount,
0046 size_t Order,
0047 class State ,
0048 class Value = double ,
0049 class Deriv = State ,
0050 class Time = Value ,
0051 class Algebra = typename algebra_dispatcher< State >::algebra_type ,
0052 class Operations = typename operations_dispatcher< State >::operations_type ,
0053 class Resizer = initially_resizer
0054 >
0055 class explicit_generic_rk;
0056
0057
0058 struct stage_vector;
0059
0060 template< class T , class Constant >
0061 struct array_wrapper
0062 {
0063     typedef const typename boost::array< T , Constant::value > type;
0064 };
0065
0066 template< class T , size_t i >
0067 struct stage
0068 {
0069     T c;
0070     boost::array< T , i > a;
0071 };
0072
0073
0074 template< class T , class Constant >
0075 struct stage_wrapper
0076 {
0077     typedef stage< T , Constant::value > type;
0078 };
0079 #endif
0080
0081
0082 template<
0083 size_t StageCount,
0084 size_t Order,
0085 class State ,
0086 class Value ,
0087 class Deriv ,
0088 class Time ,
0089 class Algebra ,
0090 class Operations ,
0091 class Resizer
0092 >
0093 #ifndef DOXYGEN_SKIP
0094 class explicit_generic_rk : public explicit_stepper_base<
0095 explicit_generic_rk< StageCount , Order , State , Value , Deriv , Time , Algebra , Operations , Resizer > ,
0096 Order , State , Value , Deriv , Time , Algebra , Operations , Resizer >
0097 #else
0098 class explicit_generic_rk : public explicit_stepper_base
0099 #endif
0100 {
0101
0102 public:
0103
0104     #ifndef DOXYGEN_SKIP
0105     typedef explicit_stepper_base<
0106             explicit_generic_rk< StageCount , Order , State , Value , Deriv ,Time , Algebra , Operations , Resizer > ,
0107             Order , State , Value , Deriv , Time , Algebra ,
0108             Operations , Resizer > stepper_base_type;
0109     #else
0110     typedef explicit_stepper_base< ... > stepper_base_type;
0111     #endif
0112
0113     typedef typename stepper_base_type::state_type state_type;
0114     typedef typename stepper_base_type::wrapped_state_type wrapped_state_type;
0115     typedef typename stepper_base_type::value_type value_type;
0116     typedef typename stepper_base_type::deriv_type deriv_type;
0117     typedef typename stepper_base_type::wrapped_deriv_type wrapped_deriv_type;
0118     typedef typename stepper_base_type::time_type time_type;
0119     typedef typename stepper_base_type::algebra_type algebra_type;
0120     typedef typename stepper_base_type::operations_type operations_type;
0121     typedef typename stepper_base_type::resizer_type resizer_type;
0122
0123     #ifndef DOXYGEN_SKIP
0124     typedef explicit_generic_rk< StageCount , Order , State , Value , Deriv ,Time , Algebra , Operations , Resizer > stepper_type;
0125     #endif
0126
0127     typedef detail::generic_rk_algorithm< StageCount , Value , Algebra , Operations > rk_algorithm_type;
0128
0129     typedef typename rk_algorithm_type::coef_a_type coef_a_type;
0130     typedef typename rk_algorithm_type::coef_b_type coef_b_type;
0131     typedef typename rk_algorithm_type::coef_c_type coef_c_type;
0132
0133     #ifndef DOXYGEN_SKIP
0134     static const size_t stage_count = StageCount;
0135     #endif
0136
0137 public:
0138
0139     explicit_generic_rk( const coef_a_type &a , const coef_b_type &b , const coef_c_type &c ,
0140             const algebra_type &algebra = algebra_type() )
0141     : stepper_base_type( algebra ) , m_rk_algorithm( a , b , c )
0142     { }
0143
0144
0145     template< class System , class StateIn , class DerivIn , class StateOut >
0146     void do_step_impl( System system , const StateIn &in , const DerivIn &dxdt ,
0147             time_type t , StateOut &out , time_type dt )
0148     {
0149         m_resizer.adjust_size( in , detail::bind( &stepper_type::template resize_impl< StateIn > , detail::ref( *this ) , detail::_1 ) );
0150
0151         // actual calculation done in generic_rk.hpp
0152         m_rk_algorithm.do_step( stepper_base_type::m_algebra , system , in , dxdt , t , out , dt , m_x_tmp.m_v , m_F );
0153     }
0154
0155     template< class StateIn >
0156     void adjust_size( const StateIn &x )
0157     {
0158         resize_impl( x );
0159         stepper_base_type::adjust_size( x );
0160     }
0161
0162 private:
0163
0164     template< class StateIn >
0165     bool resize_impl( const StateIn &x )
0166     {
0167         bool resized( false );
0168         resized |= adjust_size_by_resizeability( m_x_tmp , x , typename is_resizeable<state_type>::type() );
0169         for( size_t i = 0 ; i < StageCount-1 ; ++i )
0170         {
0171             resized |= adjust_size_by_resizeability( m_F[i] , x , typename is_resizeable<deriv_type>::type() );
0172         }
0173         return resized;
0174     }
0175
0176
0177     rk_algorithm_type m_rk_algorithm;
0178
0179     resizer_type m_resizer;
0180
0181     wrapped_state_type m_x_tmp;
0182     wrapped_deriv_type m_F[StageCount-1];
0183
0184 };
0185
0186
0187
0188 /*********** DOXYGEN *************/
0189
0190 /**
0191  * \class explicit_generic_rk
0192  * \brief A generic implementation of explicit Runge-Kutta algorithms. This class is as a base class
0193  * for all explicit Runge-Kutta steppers.
0194  *
0195  * This class implements the explicit Runge-Kutta algorithms without error estimation in a generic way.
0196  * The Butcher tableau is passed to the stepper which constructs the stepper scheme with the help of a
0197  * template-metaprogramming algorithm. ToDo : Add example!
0198  *
0199  * This class derives explicit_stepper_base which provides the stepper interface.
0200  *
0201  * \tparam StageCount The number of stages of the Runge-Kutta algorithm.
0202  * \tparam Order The order of the stepper.
0203  * \tparam State The type representing the state of the ODE.
0204  * \tparam Value The floating point type which is used in the computations.
0205  * \tparam Time The type representing the independent variable - the time - of the ODE.
0206  * \tparam Algebra The algebra type.
0207  * \tparam Operations The operations type.
0208  * \tparam Resizer The resizer policy type.
0209  */
0210
0211     /**
0212      * \fn explicit_generic_rk::explicit_generic_rk( const coef_a_type &a , const coef_b_type &b , const coef_c_type &c , const algebra_type &algebra )
0213      * \brief Constructs the explicit_generic_rk class. See examples section for details on the coefficients.
0214      * \param a Triangular matrix of parameters b in the Butcher tableau.
0215      * \param b Last row of the butcher tableau.
0216      * \param c Parameters to calculate the time points in the Butcher tableau.
0217      * \param algebra A copy of algebra is made and stored inside explicit_stepper_base.
0218      */
0219
0220     /**
0221      * \fn explicit_generic_rk::do_step_impl( System system , const StateIn &in , const DerivIn &dxdt , time_type t , StateOut &out , time_type dt )
0222      * \brief This method performs one step. The derivative `dxdt` of `in` at the time `t` is passed to the method.
0223      * The result is updated out of place, hence the input is in `in` and the output in `out`.
0224      * Access to this step functionality is provided by explicit_stepper_base and
0225      * `do_step_impl` should not be called directly.
0226      *
0227      * \param system The system function to solve, hence the r.h.s. of the ODE. It must fulfill the
0228      *               Simple System concept.
0229      * \param in The state of the ODE which should be solved. in is not modified in this method
0230      * \param dxdt The derivative of x at t.
0231      * \param t The value of the time, at which the step should be performed.
0232      * \param out The result of the step is written in out.
0233      * \param dt The step size.
0234      */
0235
0236
0237     /**
0238      * \fn explicit_generic_rk::adjust_size( const StateIn &x )
0239      * \brief Adjust the size of all temporaries in the stepper manually.
0240      * \param x A state from which the size of the temporaries to be resized is deduced.
0241      */
0242
0243 }
0244 }
0245 }
0246 #endif // BOOST_NUMERIC_ODEINT_STEPPER_EXPLICIT_GENERIC_RK_HPP_INCLUDED