Mercurial > hg > sv-dependency-builds
diff any/include/boost/math/distributions/logistic.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/logistic.hpp Sat Feb 16 16:31:25 2019 +0000 @@ -0,0 +1,299 @@ +// Copyright 2008 Gautam Sewani +// +// 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_MATH_DISTRIBUTIONS_LOGISTIC +#define BOOST_MATH_DISTRIBUTIONS_LOGISTIC + +#include <boost/math/distributions/fwd.hpp> +#include <boost/math/distributions/detail/common_error_handling.hpp> +#include <boost/math/distributions/complement.hpp> +#include <boost/math/special_functions/log1p.hpp> +#include <boost/math/constants/constants.hpp> +#include <utility> + +namespace boost { namespace math { + + template <class RealType = double, class Policy = policies::policy<> > + class logistic_distribution + { + public: + typedef RealType value_type; + typedef Policy policy_type; + + logistic_distribution(RealType l_location=0, RealType l_scale=1) // Constructor. + : m_location(l_location), m_scale(l_scale) + { + static const char* function = "boost::math::logistic_distribution<%1%>::logistic_distribution"; + + RealType result; + detail::check_scale(function, l_scale, &result, Policy()); + detail::check_location(function, l_location, &result, Policy()); + } + // Accessor functions. + RealType scale()const + { + return m_scale; + } + + RealType location()const + { + return m_location; + } + private: + // Data members: + RealType m_location; // distribution location aka mu. + RealType m_scale; // distribution scale aka s. + }; // class logistic_distribution + + + typedef logistic_distribution<double> logistic; + + template <class RealType, class Policy> + inline const std::pair<RealType, RealType> range(const logistic_distribution<RealType, Policy>& /* dist */) + { // Range of permissible values for random variable x. + using boost::math::tools::max_value; + return std::pair<RealType, RealType>( + std::numeric_limits<RealType>::has_infinity ? -std::numeric_limits<RealType>::infinity() : -max_value<RealType>(), + 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 logistic_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>(-max_value<RealType>(), max_value<RealType>()); // - to + infinity + } + + template <class RealType, class Policy> + inline RealType pdf(const logistic_distribution<RealType, Policy>& dist, const RealType& x) + { + static const char* function = "boost::math::pdf(const logistic_distribution<%1%>&, %1%)"; + RealType scale = dist.scale(); + RealType location = dist.location(); + RealType result = 0; + + if(false == detail::check_scale(function, scale , &result, Policy())) + { + return result; + } + if(false == detail::check_location(function, location, &result, Policy())) + { + return result; + } + + if((boost::math::isinf)(x)) + { + return 0; // pdf + and - infinity is zero. + } + + if(false == detail::check_x(function, x, &result, Policy())) + { + return result; + } + + BOOST_MATH_STD_USING + RealType exp_term = (location - x) / scale; + if(fabs(exp_term) > tools::log_max_value<RealType>()) + return 0; + exp_term = exp(exp_term); + if((exp_term * scale > 1) && (exp_term > tools::max_value<RealType>() / (scale * exp_term))) + return 1 / (scale * exp_term); + return (exp_term) / (scale * (1 + exp_term) * (1 + exp_term)); + } + + template <class RealType, class Policy> + inline RealType cdf(const logistic_distribution<RealType, Policy>& dist, const RealType& x) + { + RealType scale = dist.scale(); + RealType location = dist.location(); + RealType result = 0; // of checks. + static const char* function = "boost::math::cdf(const logistic_distribution<%1%>&, %1%)"; + if(false == detail::check_scale(function, scale, &result, Policy())) + { + return result; + } + if(false == detail::check_location(function, location, &result, Policy())) + { + return result; + } + + if((boost::math::isinf)(x)) + { + if(x < 0) return 0; // -infinity + return 1; // + infinity + } + + if(false == detail::check_x(function, x, &result, Policy())) + { + return result; + } + BOOST_MATH_STD_USING + RealType power = (location - x) / scale; + if(power > tools::log_max_value<RealType>()) + return 0; + if(power < -tools::log_max_value<RealType>()) + return 1; + return 1 / (1 + exp(power)); + } + + template <class RealType, class Policy> + inline RealType quantile(const logistic_distribution<RealType, Policy>& dist, const RealType& p) + { + BOOST_MATH_STD_USING + RealType location = dist.location(); + RealType scale = dist.scale(); + + static const char* function = "boost::math::quantile(const logistic_distribution<%1%>&, %1%)"; + + RealType result = 0; + if(false == detail::check_scale(function, scale, &result, Policy())) + return result; + if(false == detail::check_location(function, location, &result, Policy())) + return result; + if(false == detail::check_probability(function, p, &result, Policy())) + return result; + + if(p == 0) + { + return -policies::raise_overflow_error<RealType>(function,"probability argument is 0, must be >0 and <1",Policy()); + } + if(p == 1) + { + return policies::raise_overflow_error<RealType>(function,"probability argument is 1, must be >0 and <1",Policy()); + } + //Expressions to try + //return location+scale*log(p/(1-p)); + //return location+scale*log1p((2*p-1)/(1-p)); + + //return location - scale*log( (1-p)/p); + //return location - scale*log1p((1-2*p)/p); + + //return -scale*log(1/p-1) + location; + return location - scale * log((1 - p) / p); + } // RealType quantile(const logistic_distribution<RealType, Policy>& dist, const RealType& p) + + template <class RealType, class Policy> + inline RealType cdf(const complemented2_type<logistic_distribution<RealType, Policy>, RealType>& c) + { + BOOST_MATH_STD_USING + RealType location = c.dist.location(); + RealType scale = c.dist.scale(); + RealType x = c.param; + static const char* function = "boost::math::cdf(const complement(logistic_distribution<%1%>&), %1%)"; + + RealType result = 0; + if(false == detail::check_scale(function, scale, &result, Policy())) + { + return result; + } + if(false == detail::check_location(function, location, &result, Policy())) + { + return result; + } + if((boost::math::isinf)(x)) + { + if(x < 0) return 1; // cdf complement -infinity is unity. + return 0; // cdf complement +infinity is zero. + } + if(false == detail::check_x(function, x, &result, Policy())) + { + return result; + } + RealType power = (x - location) / scale; + if(power > tools::log_max_value<RealType>()) + return 0; + if(power < -tools::log_max_value<RealType>()) + return 1; + return 1 / (1 + exp(power)); + } + + template <class RealType, class Policy> + inline RealType quantile(const complemented2_type<logistic_distribution<RealType, Policy>, RealType>& c) + { + BOOST_MATH_STD_USING + RealType scale = c.dist.scale(); + RealType location = c.dist.location(); + static const char* function = "boost::math::quantile(const complement(logistic_distribution<%1%>&), %1%)"; + RealType result = 0; + if(false == detail::check_scale(function, scale, &result, Policy())) + return result; + if(false == detail::check_location(function, location, &result, Policy())) + return result; + RealType q = c.param; + if(false == detail::check_probability(function, q, &result, Policy())) + return result; + using boost::math::tools::max_value; + + if(q == 1) + { + return -policies::raise_overflow_error<RealType>(function,"probability argument is 1, but must be >0 and <1",Policy()); + } + if(q == 0) + { + return policies::raise_overflow_error<RealType>(function,"probability argument is 0, but must be >0 and <1",Policy()); + } + //Expressions to try + //return location+scale*log((1-q)/q); + return location + scale * log((1 - q) / q); + + //return location-scale*log(q/(1-q)); + //return location-scale*log1p((2*q-1)/(1-q)); + + //return location+scale*log(1/q-1); + //return location+scale*log1p(1/q-2); + } + + template <class RealType, class Policy> + inline RealType mean(const logistic_distribution<RealType, Policy>& dist) + { + return dist.location(); + } // RealType mean(const logistic_distribution<RealType, Policy>& dist) + + template <class RealType, class Policy> + inline RealType variance(const logistic_distribution<RealType, Policy>& dist) + { + BOOST_MATH_STD_USING + RealType scale = dist.scale(); + return boost::math::constants::pi<RealType>()*boost::math::constants::pi<RealType>()*scale*scale/3; + } // RealType variance(const logistic_distribution<RealType, Policy>& dist) + + template <class RealType, class Policy> + inline RealType mode(const logistic_distribution<RealType, Policy>& dist) + { + return dist.location(); + } + + template <class RealType, class Policy> + inline RealType median(const logistic_distribution<RealType, Policy>& dist) + { + return dist.location(); + } + template <class RealType, class Policy> + inline RealType skewness(const logistic_distribution<RealType, Policy>& /*dist*/) + { + return 0; + } // RealType skewness(const logistic_distribution<RealType, Policy>& dist) + + template <class RealType, class Policy> + inline RealType kurtosis_excess(const logistic_distribution<RealType, Policy>& /*dist*/) + { + return static_cast<RealType>(6)/5; + } // RealType kurtosis_excess(const logistic_distribution<RealType, Policy>& dist) + + template <class RealType, class Policy> + inline RealType kurtosis(const logistic_distribution<RealType, Policy>& dist) + { + return kurtosis_excess(dist) + 3; + } // RealType kurtosis_excess(const logistic_distribution<RealType, Policy>& dist) + }} + + +// Must come at the end: +#include <boost/math/distributions/detail/derived_accessors.hpp> + +#endif // BOOST_MATH_DISTRIBUTIONS_LOGISTIC