libcxx/include/__random/extreme_value_distribution.h

   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