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)
__m_(__m)43 : __m_(__m), __n_(__n) {}
44
45 _LIBCPP_INLINE_VISIBILITY
m()46 result_type m() const {return __m_;}
47 _LIBCPP_INLINE_VISIBILITY
n()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
fisher_f_distribution()65 fisher_f_distribution() : fisher_f_distribution(1) {}
66 _LIBCPP_INLINE_VISIBILITY
67 explicit fisher_f_distribution(result_type __m, result_type __n = 1)
__p_(param_type (__m,__n))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
fisher_f_distribution(const param_type & __p)75 explicit fisher_f_distribution(const param_type& __p)
76 : __p_(__p) {}
77 _LIBCPP_INLINE_VISIBILITY
reset()78 void reset() {}
79
80 // generating functions
81 template<class _URNG>
82 _LIBCPP_INLINE_VISIBILITY
operator()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
m()89 result_type m() const {return __p_.m();}
90 _LIBCPP_INLINE_VISIBILITY
n()91 result_type n() const {return __p_.n();}
92
93 _LIBCPP_INLINE_VISIBILITY
param()94 param_type param() const {return __p_;}
95 _LIBCPP_INLINE_VISIBILITY
param(const param_type & __p)96 void param(const param_type& __p) {__p_ = __p;}
97
98 _LIBCPP_INLINE_VISIBILITY
min()99 result_type min() const {return 0;}
100 _LIBCPP_INLINE_VISIBILITY
max()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
operator()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