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/uniform_real_distribution.h>
14 #include <cmath>
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 extreme_value_distribution
29 {
30 public:
31     // types
32     typedef _RealType result_type;
33 
34     class _LIBCPP_TEMPLATE_VIS param_type
35     {
36         result_type __a_;
37         result_type __b_;
38     public:
39         typedef extreme_value_distribution distribution_type;
40 
41         _LIBCPP_INLINE_VISIBILITY
42         explicit param_type(result_type __a = 0, result_type __b = 1)
43             : __a_(__a), __b_(__b) {}
44 
45         _LIBCPP_INLINE_VISIBILITY
46         result_type a() const {return __a_;}
47         _LIBCPP_INLINE_VISIBILITY
48         result_type b() const {return __b_;}
49 
50         friend _LIBCPP_INLINE_VISIBILITY
51             bool operator==(const param_type& __x, const param_type& __y)
52             {return __x.__a_ == __y.__a_ && __x.__b_ == __y.__b_;}
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     extreme_value_distribution() : extreme_value_distribution(0) {}
66     _LIBCPP_INLINE_VISIBILITY
67     explicit extreme_value_distribution(result_type __a, result_type __b = 1)
68         : __p_(param_type(__a, __b)) {}
69 #else
70     _LIBCPP_INLINE_VISIBILITY
71     explicit extreme_value_distribution(result_type __a = 0,
72                                         result_type __b = 1)
73         : __p_(param_type(__a, __b)) {}
74 #endif
75     _LIBCPP_INLINE_VISIBILITY
76     explicit extreme_value_distribution(const param_type& __p)
77         : __p_(__p) {}
78     _LIBCPP_INLINE_VISIBILITY
79     void reset() {}
80 
81     // generating functions
82     template<class _URNG>
83         _LIBCPP_INLINE_VISIBILITY
84         result_type operator()(_URNG& __g)
85         {return (*this)(__g, __p_);}
86     template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
87 
88     // property functions
89     _LIBCPP_INLINE_VISIBILITY
90     result_type a() const {return __p_.a();}
91     _LIBCPP_INLINE_VISIBILITY
92     result_type b() const {return __p_.b();}
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 -numeric_limits<result_type>::infinity();}
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 extreme_value_distribution& __x,
106                         const extreme_value_distribution& __y)
107         {return __x.__p_ == __y.__p_;}
108     friend _LIBCPP_INLINE_VISIBILITY
109         bool operator!=(const extreme_value_distribution& __x,
110                         const extreme_value_distribution& __y)
111         {return !(__x == __y);}
112 };
113 
114 template<class _RealType>
115 template<class _URNG>
116 _RealType
117 extreme_value_distribution<_RealType>::operator()(_URNG& __g, const param_type& __p)
118 {
119     return __p.a() - __p.b() *
120          _VSTD::log(-_VSTD::log(1-uniform_real_distribution<result_type>()(__g)));
121 }
122 
123 template <class _CharT, class _Traits, class _RT>
124 basic_ostream<_CharT, _Traits>&
125 operator<<(basic_ostream<_CharT, _Traits>& __os,
126            const extreme_value_distribution<_RT>& __x)
127 {
128     __save_flags<_CharT, _Traits> __lx(__os);
129     typedef basic_ostream<_CharT, _Traits> _OStream;
130     __os.flags(_OStream::dec | _OStream::left | _OStream::fixed |
131                _OStream::scientific);
132     _CharT __sp = __os.widen(' ');
133     __os.fill(__sp);
134     __os << __x.a() << __sp << __x.b();
135     return __os;
136 }
137 
138 template <class _CharT, class _Traits, class _RT>
139 basic_istream<_CharT, _Traits>&
140 operator>>(basic_istream<_CharT, _Traits>& __is,
141            extreme_value_distribution<_RT>& __x)
142 {
143     typedef extreme_value_distribution<_RT> _Eng;
144     typedef typename _Eng::result_type result_type;
145     typedef typename _Eng::param_type param_type;
146     __save_flags<_CharT, _Traits> __lx(__is);
147     typedef basic_istream<_CharT, _Traits> _Istream;
148     __is.flags(_Istream::dec | _Istream::skipws);
149     result_type __a;
150     result_type __b;
151     __is >> __a >> __b;
152     if (!__is.fail())
153         __x.param(param_type(__a, __b));
154     return __is;
155 }
156 
157 _LIBCPP_END_NAMESPACE_STD
158 
159 _LIBCPP_POP_MACROS
160 
161 #endif // _LIBCPP___RANDOM_EXTREME_VALUE_DISTRIBUTION_H
162