Mercurial > hg > vamp-build-and-test
diff DEPENDENCIES/generic/include/boost/random/normal_distribution.hpp @ 16:2665513ce2d3
Add boost headers
author | Chris Cannam |
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date | Tue, 05 Aug 2014 11:11:38 +0100 |
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children | c530137014c0 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/DEPENDENCIES/generic/include/boost/random/normal_distribution.hpp Tue Aug 05 11:11:38 2014 +0100 @@ -0,0 +1,223 @@ +/* boost random/normal_distribution.hpp header file + * + * Copyright Jens Maurer 2000-2001 + * Copyright Steven Watanabe 2010-2011 + * 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) + * + * See http://www.boost.org for most recent version including documentation. + * + * $Id: normal_distribution.hpp 71018 2011-04-05 21:27:52Z steven_watanabe $ + * + * Revision history + * 2001-02-18 moved to individual header files + */ + +#ifndef BOOST_RANDOM_NORMAL_DISTRIBUTION_HPP +#define BOOST_RANDOM_NORMAL_DISTRIBUTION_HPP + +#include <boost/config/no_tr1/cmath.hpp> +#include <istream> +#include <iosfwd> +#include <boost/assert.hpp> +#include <boost/limits.hpp> +#include <boost/static_assert.hpp> +#include <boost/random/detail/config.hpp> +#include <boost/random/detail/operators.hpp> +#include <boost/random/uniform_01.hpp> + +namespace boost { +namespace random { + +// deterministic Box-Muller method, uses trigonometric functions + +/** + * Instantiations of class template normal_distribution model a + * \random_distribution. Such a distribution produces random numbers + * @c x distributed with probability density function + * \f$\displaystyle p(x) = + * \frac{1}{\sqrt{2\pi\sigma}} e^{-\frac{(x-\mu)^2}{2\sigma^2}} + * \f$, + * where mean and sigma are the parameters of the distribution. + */ +template<class RealType = double> +class normal_distribution +{ +public: + typedef RealType input_type; + typedef RealType result_type; + + class param_type { + public: + typedef normal_distribution distribution_type; + + /** + * Constructs a @c param_type with a given mean and + * standard deviation. + * + * Requires: sigma >= 0 + */ + explicit param_type(RealType mean_arg = RealType(0.0), + RealType sigma_arg = RealType(1.0)) + : _mean(mean_arg), + _sigma(sigma_arg) + {} + + /** Returns the mean of the distribution. */ + RealType mean() const { return _mean; } + + /** Returns the standand deviation of the distribution. */ + RealType sigma() const { return _sigma; } + + /** Writes a @c param_type to a @c std::ostream. */ + BOOST_RANDOM_DETAIL_OSTREAM_OPERATOR(os, param_type, parm) + { os << parm._mean << " " << parm._sigma ; return os; } + + /** Reads a @c param_type from a @c std::istream. */ + BOOST_RANDOM_DETAIL_ISTREAM_OPERATOR(is, param_type, parm) + { is >> parm._mean >> std::ws >> parm._sigma; return is; } + + /** Returns true if the two sets of parameters are the same. */ + BOOST_RANDOM_DETAIL_EQUALITY_OPERATOR(param_type, lhs, rhs) + { return lhs._mean == rhs._mean && lhs._sigma == rhs._sigma; } + + /** Returns true if the two sets of parameters are the different. */ + BOOST_RANDOM_DETAIL_INEQUALITY_OPERATOR(param_type) + + private: + RealType _mean; + RealType _sigma; + }; + + /** + * Constructs a @c normal_distribution object. @c mean and @c sigma are + * the parameters for the distribution. + * + * Requires: sigma >= 0 + */ + explicit normal_distribution(const RealType& mean_arg = RealType(0.0), + const RealType& sigma_arg = RealType(1.0)) + : _mean(mean_arg), _sigma(sigma_arg), + _r1(0), _r2(0), _cached_rho(0), _valid(false) + { + BOOST_ASSERT(_sigma >= RealType(0)); + } + + /** + * Constructs a @c normal_distribution object from its parameters. + */ + explicit normal_distribution(const param_type& parm) + : _mean(parm.mean()), _sigma(parm.sigma()), + _r1(0), _r2(0), _cached_rho(0), _valid(false) + {} + + /** Returns the mean of the distribution. */ + RealType mean() const { return _mean; } + /** Returns the standard deviation of the distribution. */ + RealType sigma() const { return _sigma; } + + /** Returns the smallest value that the distribution can produce. */ + RealType min BOOST_PREVENT_MACRO_SUBSTITUTION () const + { return -std::numeric_limits<RealType>::infinity(); } + /** Returns the largest value that the distribution can produce. */ + RealType max BOOST_PREVENT_MACRO_SUBSTITUTION () const + { return std::numeric_limits<RealType>::infinity(); } + + /** Returns the parameters of the distribution. */ + param_type param() const { return param_type(_mean, _sigma); } + /** Sets the parameters of the distribution. */ + void param(const param_type& parm) + { + _mean = parm.mean(); + _sigma = parm.sigma(); + _valid = false; + } + + /** + * Effects: Subsequent uses of the distribution do not depend + * on values produced by any engine prior to invoking reset. + */ + void reset() { _valid = false; } + + /** Returns a normal variate. */ + template<class Engine> + result_type operator()(Engine& eng) + { + using std::sqrt; + using std::log; + using std::sin; + using std::cos; + + if(!_valid) { + _r1 = boost::uniform_01<RealType>()(eng); + _r2 = boost::uniform_01<RealType>()(eng); + _cached_rho = sqrt(-result_type(2) * log(result_type(1)-_r2)); + _valid = true; + } else { + _valid = false; + } + // Can we have a boost::mathconst please? + const result_type pi = result_type(3.14159265358979323846); + + return _cached_rho * (_valid ? + cos(result_type(2)*pi*_r1) : + sin(result_type(2)*pi*_r1)) + * _sigma + _mean; + } + + /** Returns a normal variate with parameters specified by @c param. */ + template<class URNG> + result_type operator()(URNG& urng, const param_type& parm) + { + return normal_distribution(parm)(urng); + } + + /** Writes a @c normal_distribution to a @c std::ostream. */ + BOOST_RANDOM_DETAIL_OSTREAM_OPERATOR(os, normal_distribution, nd) + { + os << nd._mean << " " << nd._sigma << " " + << nd._valid << " " << nd._cached_rho << " " << nd._r1; + return os; + } + + /** Reads a @c normal_distribution from a @c std::istream. */ + BOOST_RANDOM_DETAIL_ISTREAM_OPERATOR(is, normal_distribution, nd) + { + is >> std::ws >> nd._mean >> std::ws >> nd._sigma + >> std::ws >> nd._valid >> std::ws >> nd._cached_rho + >> std::ws >> nd._r1; + return is; + } + + /** + * Returns true if the two instances of @c normal_distribution will + * return identical sequences of values given equal generators. + */ + BOOST_RANDOM_DETAIL_EQUALITY_OPERATOR(normal_distribution, lhs, rhs) + { + return lhs._mean == rhs._mean && lhs._sigma == rhs._sigma + && lhs._valid == rhs._valid + && (!lhs._valid || (lhs._r1 == rhs._r1 && lhs._r2 == rhs._r2)); + } + + /** + * Returns true if the two instances of @c normal_distribution will + * return different sequences of values given equal generators. + */ + BOOST_RANDOM_DETAIL_INEQUALITY_OPERATOR(normal_distribution) + +private: + RealType _mean, _sigma; + RealType _r1, _r2, _cached_rho; + bool _valid; + +}; + +} // namespace random + +using random::normal_distribution; + +} // namespace boost + +#endif // BOOST_RANDOM_NORMAL_DISTRIBUTION_HPP