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_EXTREME_VALUE_DISTRIBUTION_H
10 #define _LIBCPP___RANDOM_EXTREME_VALUE_DISTRIBUTION_H
11
12 #include <__config>
13 #include <__random/is_valid.h>
14 #include <__random/uniform_real_distribution.h>
15 #include <cmath>
16 #include <iosfwd>
17 #include <limits>
18
19 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
20 # pragma GCC system_header
21 #endif
22
23 _LIBCPP_PUSH_MACROS
24 #include <__undef_macros>
25
26 _LIBCPP_BEGIN_NAMESPACE_STD
27
28 template<class _RealType = double>
29 class _LIBCPP_TEMPLATE_VIS extreme_value_distribution
30 {
31 public:
32 // types
33 typedef _RealType result_type;
34
35 class _LIBCPP_TEMPLATE_VIS param_type
36 {
37 result_type __a_;
38 result_type __b_;
39 public:
40 typedef extreme_value_distribution distribution_type;
41
42 _LIBCPP_INLINE_VISIBILITY
43 explicit param_type(result_type __a = 0, result_type __b = 1)
__a_(__a)44 : __a_(__a), __b_(__b) {}
45
46 _LIBCPP_INLINE_VISIBILITY
a()47 result_type a() const {return __a_;}
48 _LIBCPP_INLINE_VISIBILITY
b()49 result_type b() const {return __b_;}
50
51 friend _LIBCPP_INLINE_VISIBILITY
52 bool operator==(const param_type& __x, const param_type& __y)
53 {return __x.__a_ == __y.__a_ && __x.__b_ == __y.__b_;}
54 friend _LIBCPP_INLINE_VISIBILITY
55 bool operator!=(const param_type& __x, const param_type& __y)
56 {return !(__x == __y);}
57 };
58
59 private:
60 param_type __p_;
61
62 public:
63 // constructor and reset functions
64 #ifndef _LIBCPP_CXX03_LANG
65 _LIBCPP_INLINE_VISIBILITY
extreme_value_distribution()66 extreme_value_distribution() : extreme_value_distribution(0) {}
67 _LIBCPP_INLINE_VISIBILITY
68 explicit extreme_value_distribution(result_type __a, result_type __b = 1)
__p_(param_type (__a,__b))69 : __p_(param_type(__a, __b)) {}
70 #else
71 _LIBCPP_INLINE_VISIBILITY
72 explicit extreme_value_distribution(result_type __a = 0,
73 result_type __b = 1)
74 : __p_(param_type(__a, __b)) {}
75 #endif
76 _LIBCPP_INLINE_VISIBILITY
extreme_value_distribution(const param_type & __p)77 explicit extreme_value_distribution(const param_type& __p)
78 : __p_(__p) {}
79 _LIBCPP_INLINE_VISIBILITY
reset()80 void reset() {}
81
82 // generating functions
83 template<class _URNG>
84 _LIBCPP_INLINE_VISIBILITY
operator()85 result_type operator()(_URNG& __g)
86 {return (*this)(__g, __p_);}
87 template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
88
89 // property functions
90 _LIBCPP_INLINE_VISIBILITY
a()91 result_type a() const {return __p_.a();}
92 _LIBCPP_INLINE_VISIBILITY
b()93 result_type b() const {return __p_.b();}
94
95 _LIBCPP_INLINE_VISIBILITY
param()96 param_type param() const {return __p_;}
97 _LIBCPP_INLINE_VISIBILITY
param(const param_type & __p)98 void param(const param_type& __p) {__p_ = __p;}
99
100 _LIBCPP_INLINE_VISIBILITY
min()101 result_type min() const {return -numeric_limits<result_type>::infinity();}
102 _LIBCPP_INLINE_VISIBILITY
max()103 result_type max() const {return numeric_limits<result_type>::infinity();}
104
105 friend _LIBCPP_INLINE_VISIBILITY
106 bool operator==(const extreme_value_distribution& __x,
107 const extreme_value_distribution& __y)
108 {return __x.__p_ == __y.__p_;}
109 friend _LIBCPP_INLINE_VISIBILITY
110 bool operator!=(const extreme_value_distribution& __x,
111 const extreme_value_distribution& __y)
112 {return !(__x == __y);}
113 };
114
115 template<class _RealType>
116 template<class _URNG>
117 _RealType
operator()118 extreme_value_distribution<_RealType>::operator()(_URNG& __g, const param_type& __p)
119 {
120 static_assert(__libcpp_random_is_valid_urng<_URNG>::value, "");
121 return __p.a() - __p.b() *
122 _VSTD::log(-_VSTD::log(1-uniform_real_distribution<result_type>()(__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 extreme_value_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.a() << __sp << __x.b();
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 extreme_value_distribution<_RT>& __x)
144 {
145 typedef extreme_value_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 __a;
152 result_type __b;
153 __is >> __a >> __b;
154 if (!__is.fail())
155 __x.param(param_type(__a, __b));
156 return __is;
157 }
158
159 _LIBCPP_END_NAMESPACE_STD
160
161 _LIBCPP_POP_MACROS
162
163 #endif // _LIBCPP___RANDOM_EXTREME_VALUE_DISTRIBUTION_H
164