Mercurial > hg > sv-dependency-builds
diff any/include/boost/math/distributions/rayleigh.hpp @ 160:cff480c41f97
Add some cross-platform Boost headers
author | Chris Cannam <cannam@all-day-breakfast.com> |
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date | Sat, 16 Feb 2019 16:31:25 +0000 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/any/include/boost/math/distributions/rayleigh.hpp Sat Feb 16 16:31:25 2019 +0000 @@ -0,0 +1,301 @@ +// Copyright Paul A. Bristow 2007. +// Use, modification and distribution are subject to 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_STATS_rayleigh_HPP +#define BOOST_STATS_rayleigh_HPP + +#include <boost/math/distributions/fwd.hpp> +#include <boost/math/constants/constants.hpp> +#include <boost/math/special_functions/log1p.hpp> +#include <boost/math/special_functions/expm1.hpp> +#include <boost/math/distributions/complement.hpp> +#include <boost/math/distributions/detail/common_error_handling.hpp> +#include <boost/config/no_tr1/cmath.hpp> + +#ifdef BOOST_MSVC +# pragma warning(push) +# pragma warning(disable: 4702) // unreachable code (return after domain_error throw). +#endif + +#include <utility> + +namespace boost{ namespace math{ + +namespace detail +{ // Error checks: + template <class RealType, class Policy> + inline bool verify_sigma(const char* function, RealType sigma, RealType* presult, const Policy& pol) + { + if((sigma <= 0) || (!(boost::math::isfinite)(sigma))) + { + *presult = policies::raise_domain_error<RealType>( + function, + "The scale parameter \"sigma\" must be > 0 and finite, but was: %1%.", sigma, pol); + return false; + } + return true; + } // bool verify_sigma + + template <class RealType, class Policy> + inline bool verify_rayleigh_x(const char* function, RealType x, RealType* presult, const Policy& pol) + { + if((x < 0) || (boost::math::isnan)(x)) + { + *presult = policies::raise_domain_error<RealType>( + function, + "The random variable must be >= 0, but was: %1%.", x, pol); + return false; + } + return true; + } // bool verify_rayleigh_x +} // namespace detail + +template <class RealType = double, class Policy = policies::policy<> > +class rayleigh_distribution +{ +public: + typedef RealType value_type; + typedef Policy policy_type; + + rayleigh_distribution(RealType l_sigma = 1) + : m_sigma(l_sigma) + { + RealType err; + detail::verify_sigma("boost::math::rayleigh_distribution<%1%>::rayleigh_distribution", l_sigma, &err, Policy()); + } // rayleigh_distribution + + RealType sigma()const + { // Accessor. + return m_sigma; + } + +private: + RealType m_sigma; +}; // class rayleigh_distribution + +typedef rayleigh_distribution<double> rayleigh; + +template <class RealType, class Policy> +inline const std::pair<RealType, RealType> range(const rayleigh_distribution<RealType, Policy>& /*dist*/) +{ // Range of permissible values for random variable x. + using boost::math::tools::max_value; + return std::pair<RealType, RealType>(static_cast<RealType>(0), std::numeric_limits<RealType>::has_infinity ? std::numeric_limits<RealType>::infinity() : max_value<RealType>()); +} + +template <class RealType, class Policy> +inline const std::pair<RealType, RealType> support(const rayleigh_distribution<RealType, Policy>& /*dist*/) +{ // Range of supported values for random variable x. + // This is range where cdf rises from 0 to 1, and outside it, the pdf is zero. + using boost::math::tools::max_value; + return std::pair<RealType, RealType>(static_cast<RealType>(0), max_value<RealType>()); +} + +template <class RealType, class Policy> +inline RealType pdf(const rayleigh_distribution<RealType, Policy>& dist, const RealType& x) +{ + BOOST_MATH_STD_USING // for ADL of std function exp. + + RealType sigma = dist.sigma(); + RealType result = 0; + static const char* function = "boost::math::pdf(const rayleigh_distribution<%1%>&, %1%)"; + if(false == detail::verify_sigma(function, sigma, &result, Policy())) + { + return result; + } + if(false == detail::verify_rayleigh_x(function, x, &result, Policy())) + { + return result; + } + if((boost::math::isinf)(x)) + { + return 0; + } + RealType sigmasqr = sigma * sigma; + result = x * (exp(-(x * x) / ( 2 * sigmasqr))) / sigmasqr; + return result; +} // pdf + +template <class RealType, class Policy> +inline RealType cdf(const rayleigh_distribution<RealType, Policy>& dist, const RealType& x) +{ + BOOST_MATH_STD_USING // for ADL of std functions + + RealType result = 0; + RealType sigma = dist.sigma(); + static const char* function = "boost::math::cdf(const rayleigh_distribution<%1%>&, %1%)"; + if(false == detail::verify_sigma(function, sigma, &result, Policy())) + { + return result; + } + if(false == detail::verify_rayleigh_x(function, x, &result, Policy())) + { + return result; + } + result = -boost::math::expm1(-x * x / ( 2 * sigma * sigma), Policy()); + return result; +} // cdf + +template <class RealType, class Policy> +inline RealType quantile(const rayleigh_distribution<RealType, Policy>& dist, const RealType& p) +{ + BOOST_MATH_STD_USING // for ADL of std functions + + RealType result = 0; + RealType sigma = dist.sigma(); + static const char* function = "boost::math::quantile(const rayleigh_distribution<%1%>&, %1%)"; + if(false == detail::verify_sigma(function, sigma, &result, Policy())) + return result; + if(false == detail::check_probability(function, p, &result, Policy())) + return result; + + if(p == 0) + { + return 0; + } + if(p == 1) + { + return policies::raise_overflow_error<RealType>(function, 0, Policy()); + } + result = sqrt(-2 * sigma * sigma * boost::math::log1p(-p, Policy())); + return result; +} // quantile + +template <class RealType, class Policy> +inline RealType cdf(const complemented2_type<rayleigh_distribution<RealType, Policy>, RealType>& c) +{ + BOOST_MATH_STD_USING // for ADL of std functions + + RealType result = 0; + RealType sigma = c.dist.sigma(); + static const char* function = "boost::math::cdf(const rayleigh_distribution<%1%>&, %1%)"; + if(false == detail::verify_sigma(function, sigma, &result, Policy())) + { + return result; + } + RealType x = c.param; + if(false == detail::verify_rayleigh_x(function, x, &result, Policy())) + { + return result; + } + RealType ea = x * x / (2 * sigma * sigma); + // Fix for VC11/12 x64 bug in exp(float): + if (ea >= tools::max_value<RealType>()) + return 0; + result = exp(-ea); + return result; +} // cdf complement + +template <class RealType, class Policy> +inline RealType quantile(const complemented2_type<rayleigh_distribution<RealType, Policy>, RealType>& c) +{ + BOOST_MATH_STD_USING // for ADL of std functions, log & sqrt. + + RealType result = 0; + RealType sigma = c.dist.sigma(); + static const char* function = "boost::math::quantile(const rayleigh_distribution<%1%>&, %1%)"; + if(false == detail::verify_sigma(function, sigma, &result, Policy())) + { + return result; + } + RealType q = c.param; + if(false == detail::check_probability(function, q, &result, Policy())) + { + return result; + } + if(q == 1) + { + return 0; + } + if(q == 0) + { + return policies::raise_overflow_error<RealType>(function, 0, Policy()); + } + result = sqrt(-2 * sigma * sigma * log(q)); + return result; +} // quantile complement + +template <class RealType, class Policy> +inline RealType mean(const rayleigh_distribution<RealType, Policy>& dist) +{ + RealType result = 0; + RealType sigma = dist.sigma(); + static const char* function = "boost::math::mean(const rayleigh_distribution<%1%>&, %1%)"; + if(false == detail::verify_sigma(function, sigma, &result, Policy())) + { + return result; + } + using boost::math::constants::root_half_pi; + return sigma * root_half_pi<RealType>(); +} // mean + +template <class RealType, class Policy> +inline RealType variance(const rayleigh_distribution<RealType, Policy>& dist) +{ + RealType result = 0; + RealType sigma = dist.sigma(); + static const char* function = "boost::math::variance(const rayleigh_distribution<%1%>&, %1%)"; + if(false == detail::verify_sigma(function, sigma, &result, Policy())) + { + return result; + } + using boost::math::constants::four_minus_pi; + return four_minus_pi<RealType>() * sigma * sigma / 2; +} // variance + +template <class RealType, class Policy> +inline RealType mode(const rayleigh_distribution<RealType, Policy>& dist) +{ + return dist.sigma(); +} + +template <class RealType, class Policy> +inline RealType median(const rayleigh_distribution<RealType, Policy>& dist) +{ + using boost::math::constants::root_ln_four; + return root_ln_four<RealType>() * dist.sigma(); +} + +template <class RealType, class Policy> +inline RealType skewness(const rayleigh_distribution<RealType, Policy>& /*dist*/) +{ + // using namespace boost::math::constants; + return static_cast<RealType>(0.63111065781893713819189935154422777984404221106391L); + // Computed using NTL at 150 bit, about 50 decimal digits. + // return 2 * root_pi<RealType>() * pi_minus_three<RealType>() / pow23_four_minus_pi<RealType>(); +} + +template <class RealType, class Policy> +inline RealType kurtosis(const rayleigh_distribution<RealType, Policy>& /*dist*/) +{ + // using namespace boost::math::constants; + return static_cast<RealType>(3.2450893006876380628486604106197544154170667057995L); + // Computed using NTL at 150 bit, about 50 decimal digits. + // return 3 - (6 * pi<RealType>() * pi<RealType>() - 24 * pi<RealType>() + 16) / + // (four_minus_pi<RealType>() * four_minus_pi<RealType>()); +} + +template <class RealType, class Policy> +inline RealType kurtosis_excess(const rayleigh_distribution<RealType, Policy>& /*dist*/) +{ + //using namespace boost::math::constants; + // Computed using NTL at 150 bit, about 50 decimal digits. + return static_cast<RealType>(0.2450893006876380628486604106197544154170667057995L); + // return -(6 * pi<RealType>() * pi<RealType>() - 24 * pi<RealType>() + 16) / + // (four_minus_pi<RealType>() * four_minus_pi<RealType>()); +} // kurtosis + +} // namespace math +} // namespace boost + +#ifdef BOOST_MSVC +# pragma warning(pop) +#endif + +// This include must be at the end, *after* the accessors +// for this distribution have been defined, in order to +// keep compilers that support two-phase lookup happy. +#include <boost/math/distributions/detail/derived_accessors.hpp> + +#endif // BOOST_STATS_rayleigh_HPP