libcxx/include/__random/lognormal_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_LOGNORMAL_DISTRIBUTION_H
  10 #define _LIBCPP___RANDOM_LOGNORMAL_DISTRIBUTION_H
  11
  12 #include <__config>
  13 #include <__random/normal_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 lognormal_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 __s_;
  38     public:
  39         typedef lognormal_distribution distribution_type;
  40
  41         _LIBCPP_INLINE_VISIBILITY
  42         explicit param_type(result_type __m = 0, result_type __s = 1)
  43             : __m_(__m), __s_(__s) {}
  44
  45         _LIBCPP_INLINE_VISIBILITY
  46         result_type m() const {return __m_;}
  47         _LIBCPP_INLINE_VISIBILITY
  48         result_type s() const {return __s_;}
  49
  50         friend _LIBCPP_INLINE_VISIBILITY
  51         bool operator==(const param_type& __x, const param_type& __y)
  52             {return __x.__m_ == __y.__m_ && __x.__s_ == __y.__s_;}
  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     normal_distribution<result_type> __nd_;
  60
  61 public:
  62     // constructor and reset functions
  63 #ifndef _LIBCPP_CXX03_LANG
  64     _LIBCPP_INLINE_VISIBILITY
  65     lognormal_distribution() : lognormal_distribution(0) {}
  66     _LIBCPP_INLINE_VISIBILITY
  67     explicit lognormal_distribution(result_type __m, result_type __s = 1)
  68         : __nd_(__m, __s) {}
  69 #else
  70     _LIBCPP_INLINE_VISIBILITY
  71     explicit lognormal_distribution(result_type __m = 0,
  72                                     result_type __s = 1)
  73         : __nd_(__m, __s) {}
  74 #endif
  75     _LIBCPP_INLINE_VISIBILITY
  76     explicit lognormal_distribution(const param_type& __p)
  77         : __nd_(__p.m(), __p.s()) {}
  78     _LIBCPP_INLINE_VISIBILITY
  79     void reset() {__nd_.reset();}
  80
  81     // generating functions
  82     template<class _URNG>
  83     _LIBCPP_INLINE_VISIBILITY
  84     result_type operator()(_URNG& __g)
  85     {
  86         return _VSTD::exp(__nd_(__g));
  87     }
  88
  89     template<class _URNG>
  90     _LIBCPP_INLINE_VISIBILITY
  91     result_type operator()(_URNG& __g, const param_type& __p)
  92     {
  93         typename normal_distribution<result_type>::param_type __pn(__p.m(), __p.s());
  94         return _VSTD::exp(__nd_(__g, __pn));
  95     }
  96
  97     // property functions
  98     _LIBCPP_INLINE_VISIBILITY
  99     result_type m() const {return __nd_.mean();}
 100     _LIBCPP_INLINE_VISIBILITY
 101     result_type s() const {return __nd_.stddev();}
 102
 103     _LIBCPP_INLINE_VISIBILITY
 104     param_type param() const {return param_type(__nd_.mean(), __nd_.stddev());}
 105     _LIBCPP_INLINE_VISIBILITY
 106     void param(const param_type& __p)
 107     {
 108         typename normal_distribution<result_type>::param_type __pn(__p.m(), __p.s());
 109         __nd_.param(__pn);
 110     }
 111
 112     _LIBCPP_INLINE_VISIBILITY
 113     result_type min() const {return 0;}
 114     _LIBCPP_INLINE_VISIBILITY
 115     result_type max() const {return numeric_limits<result_type>::infinity();}
 116
 117     friend _LIBCPP_INLINE_VISIBILITY
 118         bool operator==(const lognormal_distribution& __x,
 119                         const lognormal_distribution& __y)
 120         {return __x.__nd_ == __y.__nd_;}
 121     friend _LIBCPP_INLINE_VISIBILITY
 122         bool operator!=(const lognormal_distribution& __x,
 123                         const lognormal_distribution& __y)
 124         {return !(__x == __y);}
 125
 126     template <class _CharT, class _Traits, class _RT>
 127     friend
 128     basic_ostream<_CharT, _Traits>&
 129     operator<<(basic_ostream<_CharT, _Traits>& __os,
 130                const lognormal_distribution<_RT>& __x);
 131
 132     template <class _CharT, class _Traits, class _RT>
 133     friend
 134     basic_istream<_CharT, _Traits>&
 135     operator>>(basic_istream<_CharT, _Traits>& __is,
 136                lognormal_distribution<_RT>& __x);
 137 };
 138
 139 template <class _CharT, class _Traits, class _RT>
 140 inline _LIBCPP_INLINE_VISIBILITY
 141 basic_ostream<_CharT, _Traits>&
 142 operator<<(basic_ostream<_CharT, _Traits>& __os,
 143            const lognormal_distribution<_RT>& __x)
 144 {
 145     return __os << __x.__nd_;
 146 }
 147
 148 template <class _CharT, class _Traits, class _RT>
 149 inline _LIBCPP_INLINE_VISIBILITY
 150 basic_istream<_CharT, _Traits>&
 151 operator>>(basic_istream<_CharT, _Traits>& __is,
 152            lognormal_distribution<_RT>& __x)
 153 {
 154     return __is >> __x.__nd_;
 155 }
 156
 157 _LIBCPP_END_NAMESPACE_STD
 158
 159 _LIBCPP_POP_MACROS
 160
 161 #endif // _LIBCPP___RANDOM_LOGNORMAL_DISTRIBUTION_H