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- // Copyright 2008 Gautam Sewani
- // Copyright 2008 John Maddock
- //
- // 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_HYPERGEOMETRIC_HPP
- #define BOOST_MATH_DISTRIBUTIONS_HYPERGEOMETRIC_HPP
- #include <boost/math/distributions/detail/common_error_handling.hpp>
- #include <boost/math/distributions/complement.hpp>
- #include <boost/math/distributions/detail/hypergeometric_pdf.hpp>
- #include <boost/math/distributions/detail/hypergeometric_cdf.hpp>
- #include <boost/math/distributions/detail/hypergeometric_quantile.hpp>
- #include <boost/math/special_functions/fpclassify.hpp>
- namespace boost { namespace math {
- template <class RealType = double, class Policy = policies::policy<> >
- class hypergeometric_distribution
- {
- public:
- typedef RealType value_type;
- typedef Policy policy_type;
- hypergeometric_distribution(unsigned r, unsigned n, unsigned N) // Constructor.
- : m_n(n), m_N(N), m_r(r)
- {
- static const char* function = "boost::math::hypergeometric_distribution<%1%>::hypergeometric_distribution";
- RealType ret;
- check_params(function, &ret);
- }
- // Accessor functions.
- unsigned total()const
- {
- return m_N;
- }
- unsigned defective()const
- {
- return m_r;
- }
- unsigned sample_count()const
- {
- return m_n;
- }
- bool check_params(const char* function, RealType* result)const
- {
- if(m_r > m_N)
- {
- *result = boost::math::policies::raise_domain_error<RealType>(
- function, "Parameter r out of range: must be <= N but got %1%", static_cast<RealType>(m_r), Policy());
- return false;
- }
- if(m_n > m_N)
- {
- *result = boost::math::policies::raise_domain_error<RealType>(
- function, "Parameter n out of range: must be <= N but got %1%", static_cast<RealType>(m_n), Policy());
- return false;
- }
- return true;
- }
- bool check_x(unsigned x, const char* function, RealType* result)const
- {
- if(x < static_cast<unsigned>((std::max)(0, (int)(m_n + m_r) - (int)(m_N))))
- {
- *result = boost::math::policies::raise_domain_error<RealType>(
- function, "Random variable out of range: must be > 0 and > m + r - N but got %1%", static_cast<RealType>(x), Policy());
- return false;
- }
- if(x > (std::min)(m_r, m_n))
- {
- *result = boost::math::policies::raise_domain_error<RealType>(
- function, "Random variable out of range: must be less than both n and r but got %1%", static_cast<RealType>(x), Policy());
- return false;
- }
- return true;
- }
- private:
- // Data members:
- unsigned m_n; // number of items picked
- unsigned m_N; // number of "total" items
- unsigned m_r; // number of "defective" items
- }; // class hypergeometric_distribution
- typedef hypergeometric_distribution<double> hypergeometric;
- template <class RealType, class Policy>
- inline const std::pair<unsigned, unsigned> range(const hypergeometric_distribution<RealType, Policy>& dist)
- { // Range of permissible values for random variable x.
- #ifdef BOOST_MSVC
- # pragma warning(push)
- # pragma warning(disable:4267)
- #endif
- unsigned r = dist.defective();
- unsigned n = dist.sample_count();
- unsigned N = dist.total();
- unsigned l = static_cast<unsigned>((std::max)(0, (int)(n + r) - (int)(N)));
- unsigned u = (std::min)(r, n);
- return std::pair<unsigned, unsigned>(l, u);
- #ifdef BOOST_MSVC
- # pragma warning(pop)
- #endif
- }
- template <class RealType, class Policy>
- inline const std::pair<unsigned, unsigned> support(const hypergeometric_distribution<RealType, Policy>& d)
- {
- return range(d);
- }
- template <class RealType, class Policy>
- inline RealType pdf(const hypergeometric_distribution<RealType, Policy>& dist, const unsigned& x)
- {
- static const char* function = "boost::math::pdf(const hypergeometric_distribution<%1%>&, const %1%&)";
- RealType result = 0;
- if(!dist.check_params(function, &result))
- return result;
- if(!dist.check_x(x, function, &result))
- return result;
- return boost::math::detail::hypergeometric_pdf<RealType>(
- x, dist.defective(), dist.sample_count(), dist.total(), Policy());
- }
- template <class RealType, class Policy, class U>
- inline RealType pdf(const hypergeometric_distribution<RealType, Policy>& dist, const U& x)
- {
- BOOST_MATH_STD_USING
- static const char* function = "boost::math::pdf(const hypergeometric_distribution<%1%>&, const %1%&)";
- RealType r = static_cast<RealType>(x);
- unsigned u = itrunc(r, typename policies::normalise<Policy, policies::rounding_error<policies::ignore_error> >::type());
- if(u != r)
- {
- return boost::math::policies::raise_domain_error<RealType>(
- function, "Random variable out of range: must be an integer but got %1%", r, Policy());
- }
- return pdf(dist, u);
- }
- template <class RealType, class Policy>
- inline RealType cdf(const hypergeometric_distribution<RealType, Policy>& dist, const unsigned& x)
- {
- static const char* function = "boost::math::cdf(const hypergeometric_distribution<%1%>&, const %1%&)";
- RealType result = 0;
- if(!dist.check_params(function, &result))
- return result;
- if(!dist.check_x(x, function, &result))
- return result;
- return boost::math::detail::hypergeometric_cdf<RealType>(
- x, dist.defective(), dist.sample_count(), dist.total(), false, Policy());
- }
- template <class RealType, class Policy, class U>
- inline RealType cdf(const hypergeometric_distribution<RealType, Policy>& dist, const U& x)
- {
- BOOST_MATH_STD_USING
- static const char* function = "boost::math::cdf(const hypergeometric_distribution<%1%>&, const %1%&)";
- RealType r = static_cast<RealType>(x);
- unsigned u = itrunc(r, typename policies::normalise<Policy, policies::rounding_error<policies::ignore_error> >::type());
- if(u != r)
- {
- return boost::math::policies::raise_domain_error<RealType>(
- function, "Random variable out of range: must be an integer but got %1%", r, Policy());
- }
- return cdf(dist, u);
- }
- template <class RealType, class Policy>
- inline RealType cdf(const complemented2_type<hypergeometric_distribution<RealType, Policy>, unsigned>& c)
- {
- static const char* function = "boost::math::cdf(const hypergeometric_distribution<%1%>&, const %1%&)";
- RealType result = 0;
- if(!c.dist.check_params(function, &result))
- return result;
- if(!c.dist.check_x(c.param, function, &result))
- return result;
- return boost::math::detail::hypergeometric_cdf<RealType>(
- c.param, c.dist.defective(), c.dist.sample_count(), c.dist.total(), true, Policy());
- }
- template <class RealType, class Policy, class U>
- inline RealType cdf(const complemented2_type<hypergeometric_distribution<RealType, Policy>, U>& c)
- {
- BOOST_MATH_STD_USING
- static const char* function = "boost::math::cdf(const hypergeometric_distribution<%1%>&, const %1%&)";
- RealType r = static_cast<RealType>(c.param);
- unsigned u = itrunc(r, typename policies::normalise<Policy, policies::rounding_error<policies::ignore_error> >::type());
- if(u != r)
- {
- return boost::math::policies::raise_domain_error<RealType>(
- function, "Random variable out of range: must be an integer but got %1%", r, Policy());
- }
- return cdf(complement(c.dist, u));
- }
- template <class RealType, class Policy>
- inline RealType quantile(const hypergeometric_distribution<RealType, Policy>& dist, const RealType& p)
- {
- BOOST_MATH_STD_USING // for ADL of std functions
- // Checking function argument
- RealType result = 0;
- const char* function = "boost::math::quantile(const hypergeometric_distribution<%1%>&, %1%)";
- if (false == dist.check_params(function, &result)) return result;
- if(false == detail::check_probability(function, p, &result, Policy())) return result;
- return static_cast<RealType>(detail::hypergeometric_quantile(p, RealType(1 - p), dist.defective(), dist.sample_count(), dist.total(), Policy()));
- } // quantile
- template <class RealType, class Policy>
- inline RealType quantile(const complemented2_type<hypergeometric_distribution<RealType, Policy>, RealType>& c)
- {
- BOOST_MATH_STD_USING // for ADL of std functions
- // Checking function argument
- RealType result = 0;
- const char* function = "quantile(const complemented2_type<hypergeometric_distribution<%1%>, %1%>&)";
- if (false == c.dist.check_params(function, &result)) return result;
- if(false == detail::check_probability(function, c.param, &result, Policy())) return result;
- return static_cast<RealType>(detail::hypergeometric_quantile(RealType(1 - c.param), c.param, c.dist.defective(), c.dist.sample_count(), c.dist.total(), Policy()));
- } // quantile
- template <class RealType, class Policy>
- inline RealType mean(const hypergeometric_distribution<RealType, Policy>& dist)
- {
- return static_cast<RealType>(dist.defective() * dist.sample_count()) / dist.total();
- } // RealType mean(const hypergeometric_distribution<RealType, Policy>& dist)
- template <class RealType, class Policy>
- inline RealType variance(const hypergeometric_distribution<RealType, Policy>& dist)
- {
- RealType r = static_cast<RealType>(dist.defective());
- RealType n = static_cast<RealType>(dist.sample_count());
- RealType N = static_cast<RealType>(dist.total());
- return n * r * (N - r) * (N - n) / (N * N * (N - 1));
- } // RealType variance(const hypergeometric_distribution<RealType, Policy>& dist)
- template <class RealType, class Policy>
- inline RealType mode(const hypergeometric_distribution<RealType, Policy>& dist)
- {
- BOOST_MATH_STD_USING
- RealType r = static_cast<RealType>(dist.defective());
- RealType n = static_cast<RealType>(dist.sample_count());
- RealType N = static_cast<RealType>(dist.total());
- return floor((r + 1) * (n + 1) / (N + 2));
- }
- template <class RealType, class Policy>
- inline RealType skewness(const hypergeometric_distribution<RealType, Policy>& dist)
- {
- BOOST_MATH_STD_USING
- RealType r = static_cast<RealType>(dist.defective());
- RealType n = static_cast<RealType>(dist.sample_count());
- RealType N = static_cast<RealType>(dist.total());
- return (N - 2 * r) * sqrt(N - 1) * (N - 2 * n) / (sqrt(n * r * (N - r) * (N - n)) * (N - 2));
- } // RealType skewness(const hypergeometric_distribution<RealType, Policy>& dist)
- template <class RealType, class Policy>
- inline RealType kurtosis_excess(const hypergeometric_distribution<RealType, Policy>& dist)
- {
- RealType r = static_cast<RealType>(dist.defective());
- RealType n = static_cast<RealType>(dist.sample_count());
- RealType N = static_cast<RealType>(dist.total());
- RealType t1 = N * N * (N - 1) / (r * (N - 2) * (N - 3) * (N - r));
- RealType t2 = (N * (N + 1) - 6 * N * (N - r)) / (n * (N - n))
- + 3 * r * (N - r) * (N + 6) / (N * N) - 6;
- return t1 * t2;
- } // RealType kurtosis_excess(const hypergeometric_distribution<RealType, Policy>& dist)
- template <class RealType, class Policy>
- inline RealType kurtosis(const hypergeometric_distribution<RealType, Policy>& dist)
- {
- return kurtosis_excess(dist) + 3;
- } // RealType kurtosis_excess(const hypergeometric_distribution<RealType, Policy>& dist)
- }} // namespaces
- // 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 // include guard
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