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author | Timothy Pearson <kb9vqf@pearsoncomputing.net> | 2013-01-26 13:16:15 -0600 |
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committer | Timothy Pearson <kb9vqf@pearsoncomputing.net> | 2013-01-26 13:16:15 -0600 |
commit | 7e09b5c2efae58399621a938de26b9675b8ba621 (patch) | |
tree | de2c9535e1f4c48ae91910492d298eba1d593fd5 /tdescreensaver/kdesavers/rkodesolver.h | |
parent | 159f7e147ac33c924b3ce9050c8f03cbc54916ee (diff) | |
download | tdeartwork-7e09b5c2efae58399621a938de26b9675b8ba621.tar.gz tdeartwork-7e09b5c2efae58399621a938de26b9675b8ba621.zip |
Rename a number of libraries and executables to avoid conflicts with KDE4
Diffstat (limited to 'tdescreensaver/kdesavers/rkodesolver.h')
-rw-r--r-- | tdescreensaver/kdesavers/rkodesolver.h | 187 |
1 files changed, 187 insertions, 0 deletions
diff --git a/tdescreensaver/kdesavers/rkodesolver.h b/tdescreensaver/kdesavers/rkodesolver.h new file mode 100644 index 00000000..d1f9d556 --- /dev/null +++ b/tdescreensaver/kdesavers/rkodesolver.h @@ -0,0 +1,187 @@ +//============================================================================ +// +// Ordinary differential equation solver using the Runge-Kutta method. +// $Id$ +// Copyright (C) 2004 Georg Drenkhahn +// +// This file is free software; you can redistribute it and/or modify it under +// the terms of the GNU General Public License version 2 as published by the +// Free Software Foundation. +// +//============================================================================ + +#ifndef RKODESOLVER_H +#define RKODESOLVER_H + +// STL headers +#include <valarray> + +/** @brief Solver class to integrate a first-order ordinary differential + * equation (ODE) by means of a 6. order Runge-Kutta method. + * + * The ODE system must be given as the derivative + * dy/dx = f(x,y) + * with x in R and y in R^n. + * + * Within this class the function f() is a pure virtual function, which must be + * reimplemented in a derived class. + * + * No other special data type for vectors or matrices are needed besides the STL + * class std::valarray. */ +template<typename T> +class RkOdeSolver +{ + public: + /** @brief Constructor + * @param x Initial integration parameter + * @param y Initial function values of function to integrate + * @param dx Initial guess for step size. Will be automatically adjusted to + * guarantee required precision. + * @param eps Relative precision + * + * Initialises the solver with start conditions. */ + RkOdeSolver(const T& x=0.0, + const std::valarray<T>& y=std::valarray<T>(0), + const T& dx=0, + const T& eps=1e-6); + /** @brief Destructor */ + virtual ~RkOdeSolver(void); + + /** @brief Integrates the ordinary differential equation from the current x + * value to x+@a dx. + * @param dx x-interval size to integrate over starting from x. dx may be + * negative. + * + * The integration is performed by calling rkStepCheck() repeatedly until the + * desired x value is reached. */ + void integrate(const T& dx); + + // Accessors + + // get/set x value + /** @brief Get current x value. + * @return Reference of x value. */ + const T& X(void) const; + /** @brief Set current x value. + * @param a The value to be set. */ + void X(const T& a); + + // get/set y value + /** @brief Get current y value. + * @return Reference of y vector. */ + const std::valarray<T>& Y(void) const; + /** @brief Set current y values. + * @param a The vector to be set. */ + void Y(const std::valarray<T>& a); + + /** @brief Get current dy/dx value. + * @return Reference of dy/dx vector. */ + const std::valarray<T>& dYdX(void) const; + + // get/set dx value + /** @brief Get current estimated step size dX. + * @return Reference of dX value. */ + const T& dX(void) const; + /** @brief Set estimated step size dX. + * @param a The value to be set. */ + void dX(const T& a); + + // get/set eps value + /** @brief Get current presision. + * @return Reference of precision value. */ + const T& Eps(void) const; + /** @brief Set estimated presision. + * @param a The value to be set. */ + void Eps(const T& a); + + protected: + // purely virtual function which is integrated + /** @brief ODE function + * @param x Integration value + * @param y Function value + * @return Derivation + * + * This purely virtual function returns the value of dy/dx for the given + * parameter values of x and y. */ + virtual std::valarray<T> + f(const T& x, const std::valarray<T>& y) const = 0; + + private: + /** @brief Perform one integration step with a tolerable relative error given + * by ::mErr. + * @param dx Maximal step size, may be positive or negative depending on + * integration direction. + * @return Flag indicating if made absolute integration step was equal |@a dx + * | (true) less than |@a dx | (false). + * + * A new estimate for the maximum next step size is saved to ::mStep. The + * new values for x, y and f are saved in ::mX, ::mY and ::mDydx. */ + bool rkStepCheck(const T& dx); + /** @brief Perform one Runge-Kutta integration step forward with step size + * ::mStep + * @param dx Step size relative to current x value. + * @param yerr Reference to vector in which the estimated error made in y is + * returned. + * @return The y value after the step at x+@a dx. + * + * Stored current x,y values are not adjusted. */ + std::valarray<T> rkStep(const T& dx, std::valarray<T>& yerr) const; + + /** current x value */ + T mX; + /** current y value */ + std::valarray<T> mY; + /** current value of dy/dx */ + std::valarray<T> mDydx; + + /** allowed relative error */ + T mEps; + /** estimated step size for next Runge-Kutta step */ + T mStep; +}; + +// inline accessors + +template<typename T> +inline const T& +RkOdeSolver<T>::X(void) const +{ + return mX; +} + +template<typename T> +inline void +RkOdeSolver<T>::X(const T &a) +{ + mX = a; +} + +template<typename T> +inline const std::valarray<T>& +RkOdeSolver<T>::Y(void) const +{ + return mY; +} + +template<typename T> +inline const std::valarray<T>& +RkOdeSolver<T>::dYdX(void) const +{ + return mDydx; +} + +template<typename T> +inline const T& +RkOdeSolver<T>::dX(void) const +{ + return mStep; +} + +template<typename T> +inline const T& +RkOdeSolver<T>::Eps(void) const +{ + return mEps; +} + +#endif |