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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
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 // types
34 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 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
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_STD
135
136_LIBCPP_POP_MACROS
137
138#endif // _LIBCPP___RANDOM_FISHER_F_DISTRIBUTION_H