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-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 #ifndef _LIBCPP___RANDOM_FISHER_F_DISTRIBUTION_H 10 #define _LIBCPP___RANDOM_FISHER_F_DISTRIBUTION_H 11 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_header 20 #endif 21 22 _LIBCPP_PUSH_MACROS 23 #include <__undef_macros> 24 25 _LIBCPP_BEGIN_NAMESPACE_STD 26 27 template<class _RealType = double> 28 class _LIBCPP_TEMPLATE_VIS fisher_f_distribution 29 { 30 public: 31 // types 32 typedef _RealType result_type; 33 34 class _LIBCPP_TEMPLATE_VIS param_type 35 { 36 result_type __m_; 37 result_type __n_; 38 public: 39 typedef fisher_f_distribution distribution_type; 40 41 _LIBCPP_INLINE_VISIBILITY 42 explicit param_type(result_type __m = 1, result_type __n = 1) 43 : __m_(__m), __n_(__n) {} 44 45 _LIBCPP_INLINE_VISIBILITY 46 result_type m() const {return __m_;} 47 _LIBCPP_INLINE_VISIBILITY 48 result_type n() const {return __n_;} 49 50 friend _LIBCPP_INLINE_VISIBILITY 51 bool operator==(const param_type& __x, const param_type& __y) 52 {return __x.__m_ == __y.__m_ && __x.__n_ == __y.__n_;} 53 friend _LIBCPP_INLINE_VISIBILITY 54 bool operator!=(const param_type& __x, const param_type& __y) 55 {return !(__x == __y);} 56 }; 57 58 private: 59 param_type __p_; 60 61 public: 62 // constructor and reset functions 63 #ifndef _LIBCPP_CXX03_LANG 64 _LIBCPP_INLINE_VISIBILITY 65 fisher_f_distribution() : fisher_f_distribution(1) {} 66 _LIBCPP_INLINE_VISIBILITY 67 explicit fisher_f_distribution(result_type __m, result_type __n = 1) 68 : __p_(param_type(__m, __n)) {} 69 #else 70 _LIBCPP_INLINE_VISIBILITY 71 explicit fisher_f_distribution(result_type __m = 1, result_type __n = 1) 72 : __p_(param_type(__m, __n)) {} 73 #endif 74 _LIBCPP_INLINE_VISIBILITY 75 explicit fisher_f_distribution(const param_type& __p) 76 : __p_(__p) {} 77 _LIBCPP_INLINE_VISIBILITY 78 void reset() {} 79 80 // generating functions 81 template<class _URNG> 82 _LIBCPP_INLINE_VISIBILITY 83 result_type operator()(_URNG& __g) 84 {return (*this)(__g, __p_);} 85 template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p); 86 87 // property functions 88 _LIBCPP_INLINE_VISIBILITY 89 result_type m() const {return __p_.m();} 90 _LIBCPP_INLINE_VISIBILITY 91 result_type n() const {return __p_.n();} 92 93 _LIBCPP_INLINE_VISIBILITY 94 param_type param() const {return __p_;} 95 _LIBCPP_INLINE_VISIBILITY 96 void param(const param_type& __p) {__p_ = __p;} 97 98 _LIBCPP_INLINE_VISIBILITY 99 result_type min() const {return 0;} 100 _LIBCPP_INLINE_VISIBILITY 101 result_type max() const {return numeric_limits<result_type>::infinity();} 102 103 friend _LIBCPP_INLINE_VISIBILITY 104 bool operator==(const fisher_f_distribution& __x, 105 const fisher_f_distribution& __y) 106 {return __x.__p_ == __y.__p_;} 107 friend _LIBCPP_INLINE_VISIBILITY 108 bool operator!=(const fisher_f_distribution& __x, 109 const fisher_f_distribution& __y) 110 {return !(__x == __y);} 111 }; 112 113 template <class _RealType> 114 template<class _URNG> 115 _RealType 116 fisher_f_distribution<_RealType>::operator()(_URNG& __g, const param_type& __p) 117 { 118 static_assert(__libcpp_random_is_valid_urng<_URNG>::value, ""); 119 gamma_distribution<result_type> __gdm(__p.m() * result_type(.5)); 120 gamma_distribution<result_type> __gdn(__p.n() * result_type(.5)); 121 return __p.n() * __gdm(__g) / (__p.m() * __gdn(__g)); 122 } 123 124 template <class _CharT, class _Traits, class _RT> 125 _LIBCPP_HIDE_FROM_ABI basic_ostream<_CharT, _Traits>& 126 operator<<(basic_ostream<_CharT, _Traits>& __os, 127 const fisher_f_distribution<_RT>& __x) 128 { 129 __save_flags<_CharT, _Traits> __lx(__os); 130 typedef basic_ostream<_CharT, _Traits> _OStream; 131 __os.flags(_OStream::dec | _OStream::left | _OStream::fixed | 132 _OStream::scientific); 133 _CharT __sp = __os.widen(' '); 134 __os.fill(__sp); 135 __os << __x.m() << __sp << __x.n(); 136 return __os; 137 } 138 139 template <class _CharT, class _Traits, class _RT> 140 _LIBCPP_HIDE_FROM_ABI basic_istream<_CharT, _Traits>& 141 operator>>(basic_istream<_CharT, _Traits>& __is, 142 fisher_f_distribution<_RT>& __x) 143 { 144 typedef fisher_f_distribution<_RT> _Eng; 145 typedef typename _Eng::result_type result_type; 146 typedef typename _Eng::param_type param_type; 147 __save_flags<_CharT, _Traits> __lx(__is); 148 typedef basic_istream<_CharT, _Traits> _Istream; 149 __is.flags(_Istream::dec | _Istream::skipws); 150 result_type __m; 151 result_type __n; 152 __is >> __m >> __n; 153 if (!__is.fail()) 154 __x.param(param_type(__m, __n)); 155 return __is; 156 } 157 158 _LIBCPP_END_NAMESPACE_STD 159 160 _LIBCPP_POP_MACROS 161 162 #endif // _LIBCPP___RANDOM_FISHER_F_DISTRIBUTION_H 163