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 static_assert(__libcpp_random_is_valid_realtype<_RealType>::value, 30 "RealType must be a supported floating-point type"); 31 32 public: 33 // types 34 typedef _RealType result_type; 35 36 class _LIBCPP_TEMPLATE_VIS 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 54 private: 55 param_type __p_; 56 57 public: 58 // constructor and reset functions 59 #ifndef _LIBCPP_CXX03_LANG 60 _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 #else 64 _LIBCPP_HIDE_FROM_ABI explicit fisher_f_distribution(result_type __m = 1, result_type __n = 1) 65 : __p_(param_type(__m, __n)) {} 66 #endif 67 _LIBCPP_HIDE_FROM_ABI explicit fisher_f_distribution(const param_type& __p) : __p_(__p) {} 68 _LIBCPP_HIDE_FROM_ABI void reset() {} 69 70 // generating functions 71 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 functions 79 _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 96 template <class _RealType> 97 template <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 } 104 105 template <class _CharT, class _Traits, class _RT> 106 _LIBCPP_HIDE_FROM_ABI basic_ostream<_CharT, _Traits>& 107 operator<<(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 } 116 117 template <class _CharT, class _Traits, class _RT> 118 _LIBCPP_HIDE_FROM_ABI basic_istream<_CharT, _Traits>& 119 operator>>(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_STD 135 136 _LIBCPP_POP_MACROS 137 138 #endif // _LIBCPP___RANDOM_FISHER_F_DISTRIBUTION_H 139