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1 | /* |
2 | [auto_generated] | |
3 | boost/numeric/odeint/stepper/explicit_error_generic_rk.hpp | |
4 | ||
5 | [begin_description] | |
6 | Implementation of the generic Runge Kutta error stepper. Base class for many RK error steppers. | |
7 | [end_description] | |
8 | ||
9 | Copyright 2011-2013 Mario Mulansky | |
10 | Copyright 2011-2013 Karsten Ahnert | |
11 | Copyright 2012 Christoph Koke | |
12 | ||
13 | Distributed under the Boost Software License, Version 1.0. | |
14 | (See accompanying file LICENSE_1_0.txt or | |
15 | copy at http://www.boost.org/LICENSE_1_0.txt) | |
16 | */ | |
17 | ||
18 | ||
19 | #ifndef BOOST_NUMERIC_ODEINT_STEPPER_EXPLICIT_ERROR_GENERIC_RK_HPP_INCLUDED | |
20 | #define BOOST_NUMERIC_ODEINT_STEPPER_EXPLICIT_ERROR_GENERIC_RK_HPP_INCLUDED | |
21 | ||
22 | #include <boost/numeric/odeint/stepper/base/explicit_error_stepper_base.hpp> | |
23 | ||
24 | #include <boost/numeric/odeint/algebra/default_operations.hpp> | |
25 | #include <boost/numeric/odeint/algebra/range_algebra.hpp> | |
26 | #include <boost/numeric/odeint/algebra/algebra_dispatcher.hpp> | |
27 | #include <boost/numeric/odeint/algebra/operations_dispatcher.hpp> | |
28 | #include <boost/numeric/odeint/stepper/detail/generic_rk_algorithm.hpp> | |
29 | #include <boost/numeric/odeint/stepper/detail/generic_rk_call_algebra.hpp> | |
30 | #include <boost/numeric/odeint/stepper/detail/generic_rk_operations.hpp> | |
31 | ||
32 | #include <boost/numeric/odeint/util/state_wrapper.hpp> | |
33 | #include <boost/numeric/odeint/util/is_resizeable.hpp> | |
34 | #include <boost/numeric/odeint/util/resizer.hpp> | |
35 | ||
36 | ||
37 | ||
38 | namespace boost { | |
39 | namespace numeric { | |
40 | namespace odeint { | |
41 | ||
42 | ||
43 | template< | |
44 | size_t StageCount, | |
45 | size_t Order, | |
46 | size_t StepperOrder , | |
47 | size_t ErrorOrder , | |
48 | class State , | |
49 | class Value = double , | |
50 | class Deriv = State , | |
51 | class Time = Value , | |
52 | class Algebra = typename algebra_dispatcher< State >::algebra_type , | |
53 | class Operations = typename operations_dispatcher< State >::operations_type , | |
54 | class Resizer = initially_resizer | |
55 | > | |
56 | #ifndef DOXYGEN_SKIP | |
57 | class explicit_error_generic_rk | |
58 | : public explicit_error_stepper_base< | |
59 | explicit_error_generic_rk< StageCount , Order , StepperOrder , ErrorOrder , State , | |
60 | Value , Deriv , Time , Algebra , Operations , Resizer > , | |
61 | Order , StepperOrder , ErrorOrder , State , Value , Deriv , Time , Algebra , | |
62 | Operations , Resizer > | |
63 | #else | |
64 | class explicit_error_generic_rk : public explicit_error_stepper_base | |
65 | #endif | |
66 | { | |
67 | ||
68 | public: | |
69 | #ifndef DOXYGEN_SKIP | |
70 | typedef explicit_error_stepper_base< | |
71 | explicit_error_generic_rk< StageCount , Order , StepperOrder , ErrorOrder , State , | |
72 | Value , Deriv , Time , Algebra , Operations , Resizer > , | |
73 | Order , StepperOrder , ErrorOrder , State , Value , Deriv , Time , Algebra , | |
74 | Operations , Resizer > stepper_base_type; | |
75 | #else | |
76 | typedef explicit_stepper_base< ... > stepper_base_type; | |
77 | #endif | |
78 | typedef typename stepper_base_type::state_type state_type; | |
79 | typedef typename stepper_base_type::wrapped_state_type wrapped_state_type; | |
80 | typedef typename stepper_base_type::value_type value_type; | |
81 | typedef typename stepper_base_type::deriv_type deriv_type; | |
82 | typedef typename stepper_base_type::wrapped_deriv_type wrapped_deriv_type; | |
83 | typedef typename stepper_base_type::time_type time_type; | |
84 | typedef typename stepper_base_type::algebra_type algebra_type; | |
85 | typedef typename stepper_base_type::operations_type operations_type; | |
86 | typedef typename stepper_base_type::resizer_type resizer_type; | |
87 | #ifndef DOXYGEN_SKIP | |
88 | typedef explicit_error_generic_rk< StageCount , Order , StepperOrder , ErrorOrder , State , | |
89 | Value , Deriv , Time , Algebra , Operations , Resizer > stepper_type; | |
90 | #endif | |
91 | typedef detail::generic_rk_algorithm< StageCount , Value , Algebra , Operations > rk_algorithm_type; | |
92 | ||
93 | typedef typename rk_algorithm_type::coef_a_type coef_a_type; | |
94 | typedef typename rk_algorithm_type::coef_b_type coef_b_type; | |
95 | typedef typename rk_algorithm_type::coef_c_type coef_c_type; | |
96 | ||
97 | static const size_t stage_count = StageCount; | |
98 | ||
99 | private: | |
100 | ||
101 | ||
102 | public: | |
103 | ||
104 | // we use an explicit_generic_rk to do the normal rk step | |
105 | // and add a separate calculation of the error estimate afterwards | |
106 | explicit_error_generic_rk( const coef_a_type &a , | |
107 | const coef_b_type &b , | |
108 | const coef_b_type &b2 , | |
109 | const coef_c_type &c , | |
110 | const algebra_type &algebra = algebra_type() ) | |
111 | : stepper_base_type( algebra ) , m_rk_algorithm( a , b , c ) , m_b2( b2 ) | |
112 | { } | |
113 | ||
114 | ||
115 | template< class System , class StateIn , class DerivIn , class StateOut , class Err > | |
116 | void do_step_impl( System system , const StateIn &in , const DerivIn &dxdt , | |
117 | time_type t , StateOut &out , time_type dt , Err &xerr ) | |
118 | { | |
119 | // normal step | |
120 | do_step_impl( system , in , dxdt , t , out , dt ); | |
121 | ||
122 | // additionally, perform the error calculation | |
123 | detail::template generic_rk_call_algebra< StageCount , algebra_type >()( stepper_base_type::m_algebra , | |
124 | xerr , dxdt , m_F , detail::generic_rk_scale_sum_err< StageCount , operations_type , value_type , time_type >( m_b2 , dt) ); | |
125 | } | |
126 | ||
127 | ||
128 | template< class System , class StateIn , class DerivIn , class StateOut > | |
129 | void do_step_impl( System system , const StateIn &in , const DerivIn &dxdt , | |
130 | time_type t , StateOut &out , time_type dt ) | |
131 | { | |
132 | m_resizer.adjust_size( in , detail::bind( &stepper_type::template resize_impl< StateIn > , detail::ref( *this ) , detail::_1 ) ); | |
133 | ||
134 | // actual calculation done in generic_rk.hpp | |
135 | m_rk_algorithm.do_step( stepper_base_type::m_algebra , system , in , dxdt , t , out , dt , m_x_tmp.m_v , m_F ); | |
136 | } | |
137 | ||
138 | ||
139 | template< class StateIn > | |
140 | void adjust_size( const StateIn &x ) | |
141 | { | |
142 | resize_impl( x ); | |
143 | stepper_base_type::adjust_size( x ); | |
144 | } | |
145 | ||
146 | ||
147 | private: | |
148 | ||
149 | template< class StateIn > | |
150 | bool resize_impl( const StateIn &x ) | |
151 | { | |
152 | bool resized( false ); | |
153 | resized |= adjust_size_by_resizeability( m_x_tmp , x , typename is_resizeable<state_type>::type() ); | |
154 | for( size_t i = 0 ; i < StageCount-1 ; ++i ) | |
155 | { | |
156 | resized |= adjust_size_by_resizeability( m_F[i] , x , typename is_resizeable<deriv_type>::type() ); | |
157 | } | |
158 | return resized; | |
159 | } | |
160 | ||
161 | ||
162 | rk_algorithm_type m_rk_algorithm; | |
163 | coef_b_type m_b2; | |
164 | ||
165 | resizer_type m_resizer; | |
166 | ||
167 | wrapped_state_type m_x_tmp; | |
168 | wrapped_deriv_type m_F[StageCount-1]; | |
169 | ||
170 | }; | |
171 | ||
172 | ||
173 | /********* DOXYGEN *********/ | |
174 | ||
175 | /** | |
176 | * \class explicit_error_generic_rk | |
177 | * \brief A generic implementation of explicit Runge-Kutta algorithms with error estimation. This class is as a | |
178 | * base class for all explicit Runge-Kutta steppers with error estimation. | |
179 | * | |
180 | * This class implements the explicit Runge-Kutta algorithms with error estimation in a generic way. | |
181 | * The Butcher tableau is passed to the stepper which constructs the stepper scheme with the help of a | |
182 | * template-metaprogramming algorithm. ToDo : Add example! | |
183 | * | |
184 | * This class derives explicit_error_stepper_base which provides the stepper interface. | |
185 | * | |
186 | * \tparam StageCount The number of stages of the Runge-Kutta algorithm. | |
187 | * \tparam Order The order of a stepper if the stepper is used without error estimation. | |
188 | * \tparam StepperOrder The order of a step if the stepper is used with error estimation. Usually Order and StepperOrder have | |
189 | * the same value. | |
190 | * \tparam ErrorOrder The order of the error step if the stepper is used with error estimation. | |
191 | * \tparam State The type representing the state of the ODE. | |
192 | * \tparam Value The floating point type which is used in the computations. | |
193 | * \tparam Time The type representing the independent variable - the time - of the ODE. | |
194 | * \tparam Algebra The algebra type. | |
195 | * \tparam Operations The operations type. | |
196 | * \tparam Resizer The resizer policy type. | |
197 | */ | |
198 | ||
199 | ||
200 | /** | |
201 | * \fn explicit_error_generic_rk::explicit_error_generic_rk( const coef_a_type &a , const coef_b_type &b , const coef_b_type &b2 , const coef_c_type &c , const algebra_type &algebra ) | |
202 | * \brief Constructs the explicit_error_generik_rk class with the given parameters a, b, b2 and c. See examples section for details on the coefficients. | |
203 | * | |
204 | * \param a Triangular matrix of parameters b in the Butcher tableau. | |
205 | * \param b Last row of the butcher tableau. | |
206 | * \param b2 Parameters for lower-order evaluation to estimate the error. | |
207 | * \param c Parameters to calculate the time points in the Butcher tableau. | |
208 | * \param algebra A copy of algebra is made and stored inside explicit_stepper_base. | |
209 | */ | |
210 | ||
211 | ||
212 | /** | |
213 | * \fn explicit_error_generic_rk::do_step_impl( System system , const StateIn &in , const DerivIn &dxdt , time_type t , StateOut &out , time_type dt , Err &xerr ) | |
214 | * \brief This method performs one step. The derivative `dxdt` of `in` at the time `t` is passed to the method. | |
215 | * The result is updated out-of-place, hence the input is in `in` and the output in `out`. Futhermore, an | |
216 | * estimation of the error is stored in `xerr`. `do_step_impl` is used by explicit_error_stepper_base. | |
217 | * | |
218 | * \param system The system function to solve, hence the r.h.s. of the ODE. It must fulfill the | |
219 | * Simple System concept. | |
220 | * \param in The state of the ODE which should be solved. in is not modified in this method | |
221 | * \param dxdt The derivative of x at t. | |
222 | * \param t The value of the time, at which the step should be performed. | |
223 | * \param out The result of the step is written in out. | |
224 | * \param dt The step size. | |
225 | * \param xerr The result of the error estimation is written in xerr. | |
226 | */ | |
227 | ||
228 | /** | |
229 | * \fn explicit_error_generic_rk::do_step_impl( System system , const StateIn &in , const DerivIn &dxdt , time_type t , StateOut &out , time_type dt ) | |
230 | * \brief This method performs one step. The derivative `dxdt` of `in` at the time `t` is passed to the method. | |
231 | * The result is updated out-of-place, hence the input is in `in` and the output in `out`. | |
232 | * Access to this step functionality is provided by explicit_stepper_base and | |
233 | * `do_step_impl` should not be called directly. | |
234 | * | |
235 | * \param system The system function to solve, hence the r.h.s. of the ODE. It must fulfill the | |
236 | * Simple System concept. | |
237 | * \param in The state of the ODE which should be solved. in is not modified in this method | |
238 | * \param dxdt The derivative of x at t. | |
239 | * \param t The value of the time, at which the step should be performed. | |
240 | * \param out The result of the step is written in out. | |
241 | * \param dt The step size. | |
242 | */ | |
243 | ||
244 | /** | |
245 | * \fn explicit_error_generic_rk::adjust_size( const StateIn &x ) | |
246 | * \brief Adjust the size of all temporaries in the stepper manually. | |
247 | * \param x A state from which the size of the temporaries to be resized is deduced. | |
248 | */ | |
249 | ||
250 | } | |
251 | } | |
252 | } | |
253 | ||
254 | ||
255 | #endif // BOOST_NUMERIC_ODEINT_STEPPER_EXPLICIT_ERROR_GENERIC_RK_HPP_INCLUDED |