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> 86 _LIBCPP_HIDE_FROM_ABI result_type operator()(_URNG& __g, const param_type& __p); 87 88 // property functions 89 _LIBCPP_INLINE_VISIBILITY 90 result_type m() const {return __p_.m();} 91 _LIBCPP_INLINE_VISIBILITY 92 result_type n() const {return __p_.n();} 93 94 _LIBCPP_INLINE_VISIBILITY 95 param_type param() const {return __p_;} 96 _LIBCPP_INLINE_VISIBILITY 97 void param(const param_type& __p) {__p_ = __p;} 98 99 _LIBCPP_INLINE_VISIBILITY 100 result_type min() const {return 0;} 101 _LIBCPP_INLINE_VISIBILITY 102 result_type max() const {return numeric_limits<result_type>::infinity();} 103 104 friend _LIBCPP_INLINE_VISIBILITY 105 bool operator==(const fisher_f_distribution& __x, 106 const fisher_f_distribution& __y) 107 {return __x.__p_ == __y.__p_;} 108 friend _LIBCPP_INLINE_VISIBILITY 109 bool operator!=(const fisher_f_distribution& __x, 110 const fisher_f_distribution& __y) 111 {return !(__x == __y);} 112 }; 113 114 template <class _RealType> 115 template<class _URNG> 116 _RealType 117 fisher_f_distribution<_RealType>::operator()(_URNG& __g, const param_type& __p) 118 { 119 static_assert(__libcpp_random_is_valid_urng<_URNG>::value, ""); 120 gamma_distribution<result_type> __gdm(__p.m() * result_type(.5)); 121 gamma_distribution<result_type> __gdn(__p.n() * result_type(.5)); 122 return __p.n() * __gdm(__g) / (__p.m() * __gdn(__g)); 123 } 124 125 template <class _CharT, class _Traits, class _RT> 126 _LIBCPP_HIDE_FROM_ABI basic_ostream<_CharT, _Traits>& 127 operator<<(basic_ostream<_CharT, _Traits>& __os, 128 const fisher_f_distribution<_RT>& __x) 129 { 130 __save_flags<_CharT, _Traits> __lx(__os); 131 typedef basic_ostream<_CharT, _Traits> _OStream; 132 __os.flags(_OStream::dec | _OStream::left | _OStream::fixed | 133 _OStream::scientific); 134 _CharT __sp = __os.widen(' '); 135 __os.fill(__sp); 136 __os << __x.m() << __sp << __x.n(); 137 return __os; 138 } 139 140 template <class _CharT, class _Traits, class _RT> 141 _LIBCPP_HIDE_FROM_ABI basic_istream<_CharT, _Traits>& 142 operator>>(basic_istream<_CharT, _Traits>& __is, 143 fisher_f_distribution<_RT>& __x) 144 { 145 typedef fisher_f_distribution<_RT> _Eng; 146 typedef typename _Eng::result_type result_type; 147 typedef typename _Eng::param_type param_type; 148 __save_flags<_CharT, _Traits> __lx(__is); 149 typedef basic_istream<_CharT, _Traits> _Istream; 150 __is.flags(_Istream::dec | _Istream::skipws); 151 result_type __m; 152 result_type __n; 153 __is >> __m >> __n; 154 if (!__is.fail()) 155 __x.param(param_type(__m, __n)); 156 return __is; 157 } 158 159 _LIBCPP_END_NAMESPACE_STD 160 161 _LIBCPP_POP_MACROS 162 163 #endif // _LIBCPP___RANDOM_FISHER_F_DISTRIBUTION_H 164