Mercurial > hg > sv-dependency-builds
diff any/include/boost/math/distributions/lognormal.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/lognormal.hpp Sat Feb 16 16:31:25 2019 +0000 @@ -0,0 +1,341 @@ +// Copyright John Maddock 2006. +// 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_LOGNORMAL_HPP +#define BOOST_STATS_LOGNORMAL_HPP + +// http://www.itl.nist.gov/div898/handbook/eda/section3/eda3669.htm +// http://mathworld.wolfram.com/LogNormalDistribution.html +// http://en.wikipedia.org/wiki/Lognormal_distribution + +#include <boost/math/distributions/fwd.hpp> +#include <boost/math/distributions/normal.hpp> +#include <boost/math/special_functions/expm1.hpp> +#include <boost/math/distributions/detail/common_error_handling.hpp> + +#include <utility> + +namespace boost{ namespace math +{ +namespace detail +{ + + template <class RealType, class Policy> + inline bool check_lognormal_x( + const char* function, + RealType const& x, + RealType* result, const Policy& pol) + { + if((x < 0) || !(boost::math::isfinite)(x)) + { + *result = policies::raise_domain_error<RealType>( + function, + "Random variate is %1% but must be >= 0 !", x, pol); + return false; + } + return true; + } + +} // namespace detail + + +template <class RealType = double, class Policy = policies::policy<> > +class lognormal_distribution +{ +public: + typedef RealType value_type; + typedef Policy policy_type; + + lognormal_distribution(RealType l_location = 0, RealType l_scale = 1) + : m_location(l_location), m_scale(l_scale) + { + RealType result; + detail::check_scale("boost::math::lognormal_distribution<%1%>::lognormal_distribution", l_scale, &result, Policy()); + detail::check_location("boost::math::lognormal_distribution<%1%>::lognormal_distribution", l_location, &result, Policy()); + } + + RealType location()const + { + return m_location; + } + + RealType scale()const + { + return m_scale; + } +private: + // + // Data members: + // + RealType m_location; // distribution location. + RealType m_scale; // distribution scale. +}; + +typedef lognormal_distribution<double> lognormal; + +template <class RealType, class Policy> +inline const std::pair<RealType, RealType> range(const lognormal_distribution<RealType, Policy>& /*dist*/) +{ // Range of permissible values for random variable x is >0 to +infinity. + using boost::math::tools::max_value; + return std::pair<RealType, RealType>(static_cast<RealType>(0), max_value<RealType>()); +} + +template <class RealType, class Policy> +inline const std::pair<RealType, RealType> support(const lognormal_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> +RealType pdf(const lognormal_distribution<RealType, Policy>& dist, const RealType& x) +{ + BOOST_MATH_STD_USING // for ADL of std functions + + RealType mu = dist.location(); + RealType sigma = dist.scale(); + + static const char* function = "boost::math::pdf(const lognormal_distribution<%1%>&, %1%)"; + + RealType result = 0; + if(0 == detail::check_scale(function, sigma, &result, Policy())) + return result; + if(0 == detail::check_location(function, mu, &result, Policy())) + return result; + if(0 == detail::check_lognormal_x(function, x, &result, Policy())) + return result; + + if(x == 0) + return 0; + + RealType exponent = log(x) - mu; + exponent *= -exponent; + exponent /= 2 * sigma * sigma; + + result = exp(exponent); + result /= sigma * sqrt(2 * constants::pi<RealType>()) * x; + + return result; +} + +template <class RealType, class Policy> +inline RealType cdf(const lognormal_distribution<RealType, Policy>& dist, const RealType& x) +{ + BOOST_MATH_STD_USING // for ADL of std functions + + static const char* function = "boost::math::cdf(const lognormal_distribution<%1%>&, %1%)"; + + RealType result = 0; + if(0 == detail::check_scale(function, dist.scale(), &result, Policy())) + return result; + if(0 == detail::check_location(function, dist.location(), &result, Policy())) + return result; + if(0 == detail::check_lognormal_x(function, x, &result, Policy())) + return result; + + if(x == 0) + return 0; + + normal_distribution<RealType, Policy> norm(dist.location(), dist.scale()); + return cdf(norm, log(x)); +} + +template <class RealType, class Policy> +inline RealType quantile(const lognormal_distribution<RealType, Policy>& dist, const RealType& p) +{ + BOOST_MATH_STD_USING // for ADL of std functions + + static const char* function = "boost::math::quantile(const lognormal_distribution<%1%>&, %1%)"; + + RealType result = 0; + if(0 == detail::check_scale(function, dist.scale(), &result, Policy())) + return result; + if(0 == detail::check_location(function, dist.location(), &result, Policy())) + return result; + if(0 == 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()); + + normal_distribution<RealType, Policy> norm(dist.location(), dist.scale()); + return exp(quantile(norm, p)); +} + +template <class RealType, class Policy> +inline RealType cdf(const complemented2_type<lognormal_distribution<RealType, Policy>, RealType>& c) +{ + BOOST_MATH_STD_USING // for ADL of std functions + + static const char* function = "boost::math::cdf(const lognormal_distribution<%1%>&, %1%)"; + + RealType result = 0; + if(0 == detail::check_scale(function, c.dist.scale(), &result, Policy())) + return result; + if(0 == detail::check_location(function, c.dist.location(), &result, Policy())) + return result; + if(0 == detail::check_lognormal_x(function, c.param, &result, Policy())) + return result; + + if(c.param == 0) + return 1; + + normal_distribution<RealType, Policy> norm(c.dist.location(), c.dist.scale()); + return cdf(complement(norm, log(c.param))); +} + +template <class RealType, class Policy> +inline RealType quantile(const complemented2_type<lognormal_distribution<RealType, Policy>, RealType>& c) +{ + BOOST_MATH_STD_USING // for ADL of std functions + + static const char* function = "boost::math::quantile(const lognormal_distribution<%1%>&, %1%)"; + + RealType result = 0; + if(0 == detail::check_scale(function, c.dist.scale(), &result, Policy())) + return result; + if(0 == detail::check_location(function, c.dist.location(), &result, Policy())) + return result; + if(0 == detail::check_probability(function, c.param, &result, Policy())) + return result; + + if(c.param == 1) + return 0; + if(c.param == 0) + return policies::raise_overflow_error<RealType>(function, 0, Policy()); + + normal_distribution<RealType, Policy> norm(c.dist.location(), c.dist.scale()); + return exp(quantile(complement(norm, c.param))); +} + +template <class RealType, class Policy> +inline RealType mean(const lognormal_distribution<RealType, Policy>& dist) +{ + BOOST_MATH_STD_USING // for ADL of std functions + + RealType mu = dist.location(); + RealType sigma = dist.scale(); + + RealType result = 0; + if(0 == detail::check_scale("boost::math::mean(const lognormal_distribution<%1%>&)", sigma, &result, Policy())) + return result; + if(0 == detail::check_location("boost::math::mean(const lognormal_distribution<%1%>&)", mu, &result, Policy())) + return result; + + return exp(mu + sigma * sigma / 2); +} + +template <class RealType, class Policy> +inline RealType variance(const lognormal_distribution<RealType, Policy>& dist) +{ + BOOST_MATH_STD_USING // for ADL of std functions + + RealType mu = dist.location(); + RealType sigma = dist.scale(); + + RealType result = 0; + if(0 == detail::check_scale("boost::math::variance(const lognormal_distribution<%1%>&)", sigma, &result, Policy())) + return result; + if(0 == detail::check_location("boost::math::variance(const lognormal_distribution<%1%>&)", mu, &result, Policy())) + return result; + + return boost::math::expm1(sigma * sigma, Policy()) * exp(2 * mu + sigma * sigma); +} + +template <class RealType, class Policy> +inline RealType mode(const lognormal_distribution<RealType, Policy>& dist) +{ + BOOST_MATH_STD_USING // for ADL of std functions + + RealType mu = dist.location(); + RealType sigma = dist.scale(); + + RealType result = 0; + if(0 == detail::check_scale("boost::math::mode(const lognormal_distribution<%1%>&)", sigma, &result, Policy())) + return result; + if(0 == detail::check_location("boost::math::mode(const lognormal_distribution<%1%>&)", mu, &result, Policy())) + return result; + + return exp(mu - sigma * sigma); +} + +template <class RealType, class Policy> +inline RealType median(const lognormal_distribution<RealType, Policy>& dist) +{ + BOOST_MATH_STD_USING // for ADL of std functions + RealType mu = dist.location(); + return exp(mu); // e^mu +} + +template <class RealType, class Policy> +inline RealType skewness(const lognormal_distribution<RealType, Policy>& dist) +{ + BOOST_MATH_STD_USING // for ADL of std functions + + //RealType mu = dist.location(); + RealType sigma = dist.scale(); + + RealType ss = sigma * sigma; + RealType ess = exp(ss); + + RealType result = 0; + if(0 == detail::check_scale("boost::math::skewness(const lognormal_distribution<%1%>&)", sigma, &result, Policy())) + return result; + if(0 == detail::check_location("boost::math::skewness(const lognormal_distribution<%1%>&)", dist.location(), &result, Policy())) + return result; + + return (ess + 2) * sqrt(boost::math::expm1(ss, Policy())); +} + +template <class RealType, class Policy> +inline RealType kurtosis(const lognormal_distribution<RealType, Policy>& dist) +{ + BOOST_MATH_STD_USING // for ADL of std functions + + //RealType mu = dist.location(); + RealType sigma = dist.scale(); + RealType ss = sigma * sigma; + + RealType result = 0; + if(0 == detail::check_scale("boost::math::kurtosis(const lognormal_distribution<%1%>&)", sigma, &result, Policy())) + return result; + if(0 == detail::check_location("boost::math::kurtosis(const lognormal_distribution<%1%>&)", dist.location(), &result, Policy())) + return result; + + return exp(4 * ss) + 2 * exp(3 * ss) + 3 * exp(2 * ss) - 3; +} + +template <class RealType, class Policy> +inline RealType kurtosis_excess(const lognormal_distribution<RealType, Policy>& dist) +{ + BOOST_MATH_STD_USING // for ADL of std functions + + // RealType mu = dist.location(); + RealType sigma = dist.scale(); + RealType ss = sigma * sigma; + + RealType result = 0; + if(0 == detail::check_scale("boost::math::kurtosis_excess(const lognormal_distribution<%1%>&)", sigma, &result, Policy())) + return result; + if(0 == detail::check_location("boost::math::kurtosis_excess(const lognormal_distribution<%1%>&)", dist.location(), &result, Policy())) + return result; + + return exp(4 * ss) + 2 * exp(3 * ss) + 3 * exp(2 * ss) - 6; +} + +} // namespace math +} // namespace boost + +// 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_STUDENTS_T_HPP + +