139 lines · c
1//===----------------------------------------------------------------------===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8 9#ifndef _LIBCPP___RANDOM_FISHER_F_DISTRIBUTION_H10#define _LIBCPP___RANDOM_FISHER_F_DISTRIBUTION_H11 12#include <__config>13#include <__random/gamma_distribution.h>14#include <__random/is_valid.h>15#include <iosfwd>16#include <limits>17 18#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)19# pragma GCC system_header20#endif21 22_LIBCPP_PUSH_MACROS23#include <__undef_macros>24 25_LIBCPP_BEGIN_NAMESPACE_STD26 27template <class _RealType = double>28class fisher_f_distribution {29 static_assert(__libcpp_random_is_valid_realtype<_RealType>::value,30 "RealType must be a supported floating-point type");31 32public:33 // types34 typedef _RealType result_type;35 36 class param_type {37 result_type __m_;38 result_type __n_;39 40 public:41 typedef fisher_f_distribution distribution_type;42 43 _LIBCPP_HIDE_FROM_ABI explicit param_type(result_type __m = 1, result_type __n = 1) : __m_(__m), __n_(__n) {}44 45 _LIBCPP_HIDE_FROM_ABI result_type m() const { return __m_; }46 _LIBCPP_HIDE_FROM_ABI result_type n() const { return __n_; }47 48 friend _LIBCPP_HIDE_FROM_ABI bool operator==(const param_type& __x, const param_type& __y) {49 return __x.__m_ == __y.__m_ && __x.__n_ == __y.__n_;50 }51 friend _LIBCPP_HIDE_FROM_ABI bool operator!=(const param_type& __x, const param_type& __y) { return !(__x == __y); }52 };53 54private:55 param_type __p_;56 57public:58 // constructor and reset functions59#ifndef _LIBCPP_CXX03_LANG60 _LIBCPP_HIDE_FROM_ABI fisher_f_distribution() : fisher_f_distribution(1) {}61 _LIBCPP_HIDE_FROM_ABI explicit fisher_f_distribution(result_type __m, result_type __n = 1)62 : __p_(param_type(__m, __n)) {}63#else64 _LIBCPP_HIDE_FROM_ABI explicit fisher_f_distribution(result_type __m = 1, result_type __n = 1)65 : __p_(param_type(__m, __n)) {}66#endif67 _LIBCPP_HIDE_FROM_ABI explicit fisher_f_distribution(const param_type& __p) : __p_(__p) {}68 _LIBCPP_HIDE_FROM_ABI void reset() {}69 70 // generating functions71 template <class _URNG>72 _LIBCPP_HIDE_FROM_ABI result_type operator()(_URNG& __g) {73 return (*this)(__g, __p_);74 }75 template <class _URNG>76 _LIBCPP_HIDE_FROM_ABI result_type operator()(_URNG& __g, const param_type& __p);77 78 // property functions79 _LIBCPP_HIDE_FROM_ABI result_type m() const { return __p_.m(); }80 _LIBCPP_HIDE_FROM_ABI result_type n() const { return __p_.n(); }81 82 _LIBCPP_HIDE_FROM_ABI param_type param() const { return __p_; }83 _LIBCPP_HIDE_FROM_ABI void param(const param_type& __p) { __p_ = __p; }84 85 _LIBCPP_HIDE_FROM_ABI result_type min() const { return 0; }86 _LIBCPP_HIDE_FROM_ABI result_type max() const { return numeric_limits<result_type>::infinity(); }87 88 friend _LIBCPP_HIDE_FROM_ABI bool operator==(const fisher_f_distribution& __x, const fisher_f_distribution& __y) {89 return __x.__p_ == __y.__p_;90 }91 friend _LIBCPP_HIDE_FROM_ABI bool operator!=(const fisher_f_distribution& __x, const fisher_f_distribution& __y) {92 return !(__x == __y);93 }94};95 96template <class _RealType>97template <class _URNG>98_RealType fisher_f_distribution<_RealType>::operator()(_URNG& __g, const param_type& __p) {99 static_assert(__libcpp_random_is_valid_urng<_URNG>::value, "");100 gamma_distribution<result_type> __gdm(__p.m() * result_type(.5));101 gamma_distribution<result_type> __gdn(__p.n() * result_type(.5));102 return __p.n() * __gdm(__g) / (__p.m() * __gdn(__g));103}104 105template <class _CharT, class _Traits, class _RT>106_LIBCPP_HIDE_FROM_ABI basic_ostream<_CharT, _Traits>&107operator<<(basic_ostream<_CharT, _Traits>& __os, const fisher_f_distribution<_RT>& __x) {108 __save_flags<_CharT, _Traits> __lx(__os);109 typedef basic_ostream<_CharT, _Traits> _OStream;110 __os.flags(_OStream::dec | _OStream::left | _OStream::fixed | _OStream::scientific);111 _CharT __sp = __os.widen(' ');112 __os.fill(__sp);113 __os << __x.m() << __sp << __x.n();114 return __os;115}116 117template <class _CharT, class _Traits, class _RT>118_LIBCPP_HIDE_FROM_ABI basic_istream<_CharT, _Traits>&119operator>>(basic_istream<_CharT, _Traits>& __is, fisher_f_distribution<_RT>& __x) {120 typedef fisher_f_distribution<_RT> _Eng;121 typedef typename _Eng::result_type result_type;122 typedef typename _Eng::param_type param_type;123 __save_flags<_CharT, _Traits> __lx(__is);124 typedef basic_istream<_CharT, _Traits> _Istream;125 __is.flags(_Istream::dec | _Istream::skipws);126 result_type __m;127 result_type __n;128 __is >> __m >> __n;129 if (!__is.fail())130 __x.param(param_type(__m, __n));131 return __is;132}133 134_LIBCPP_END_NAMESPACE_STD135 136_LIBCPP_POP_MACROS137 138#endif // _LIBCPP___RANDOM_FISHER_F_DISTRIBUTION_H139