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/is_valid.h>
  14 #include <__random/normal_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 lognormal_distribution {
  30   static_assert(__libcpp_random_is_valid_realtype<_RealType>::value,
  31                 "RealType must be a supported floating-point type");
  32
  33 public:
  34   // types
  35   typedef _RealType result_type;
  36
  37   class _LIBCPP_TEMPLATE_VIS param_type {
  38     result_type __m_;
  39     result_type __s_;
  40
  41   public:
  42     typedef lognormal_distribution distribution_type;
  43
  44     _LIBCPP_HIDE_FROM_ABI explicit param_type(result_type __m = 0, result_type __s = 1) : __m_(__m), __s_(__s) {}
  45
  46     _LIBCPP_HIDE_FROM_ABI result_type m() const { return __m_; }
  47     _LIBCPP_HIDE_FROM_ABI result_type s() const { return __s_; }
  48
  49     friend _LIBCPP_HIDE_FROM_ABI bool operator==(const param_type& __x, const param_type& __y) {
  50       return __x.__m_ == __y.__m_ && __x.__s_ == __y.__s_;
  51     }
  52     friend _LIBCPP_HIDE_FROM_ABI bool operator!=(const param_type& __x, const param_type& __y) { return !(__x == __y); }
  53   };
  54
  55 private:
  56   normal_distribution<result_type> __nd_;
  57
  58 public:
  59   // constructor and reset functions
  60 #ifndef _LIBCPP_CXX03_LANG
  61   _LIBCPP_HIDE_FROM_ABI lognormal_distribution() : lognormal_distribution(0) {}
  62   _LIBCPP_HIDE_FROM_ABI explicit lognormal_distribution(result_type __m, result_type __s = 1) : __nd_(__m, __s) {}
  63 #else
  64   _LIBCPP_HIDE_FROM_ABI explicit lognormal_distribution(result_type __m = 0, result_type __s = 1) : __nd_(__m, __s) {}
  65 #endif
  66   _LIBCPP_HIDE_FROM_ABI explicit lognormal_distribution(const param_type& __p) : __nd_(__p.m(), __p.s()) {}
  67   _LIBCPP_HIDE_FROM_ABI void reset() { __nd_.reset(); }
  68
  69   // generating functions
  70   template <class _URNG>
  71   _LIBCPP_HIDE_FROM_ABI result_type operator()(_URNG& __g) {
  72     return std::exp(__nd_(__g));
  73   }
  74
  75   template <class _URNG>
  76   _LIBCPP_HIDE_FROM_ABI result_type operator()(_URNG& __g, const param_type& __p) {
  77     typename normal_distribution<result_type>::param_type __pn(__p.m(), __p.s());
  78     return std::exp(__nd_(__g, __pn));
  79   }
  80
  81   // property functions
  82   _LIBCPP_HIDE_FROM_ABI result_type m() const { return __nd_.mean(); }
  83   _LIBCPP_HIDE_FROM_ABI result_type s() const { return __nd_.stddev(); }
  84
  85   _LIBCPP_HIDE_FROM_ABI param_type param() const { return param_type(__nd_.mean(), __nd_.stddev()); }
  86   _LIBCPP_HIDE_FROM_ABI void param(const param_type& __p) {
  87     typename normal_distribution<result_type>::param_type __pn(__p.m(), __p.s());
  88     __nd_.param(__pn);
  89   }
  90
  91   _LIBCPP_HIDE_FROM_ABI result_type min() const { return 0; }
  92   _LIBCPP_HIDE_FROM_ABI result_type max() const { return numeric_limits<result_type>::infinity(); }
  93
  94   friend _LIBCPP_HIDE_FROM_ABI bool operator==(const lognormal_distribution& __x, const lognormal_distribution& __y) {
  95     return __x.__nd_ == __y.__nd_;
  96   }
  97   friend _LIBCPP_HIDE_FROM_ABI bool operator!=(const lognormal_distribution& __x, const lognormal_distribution& __y) {
  98     return !(__x == __y);
  99   }
 100
 101   template <class _CharT, class _Traits, class _RT>
 102   friend basic_ostream<_CharT, _Traits>&
 103   operator<<(basic_ostream<_CharT, _Traits>& __os, const lognormal_distribution<_RT>& __x);
 104
 105   template <class _CharT, class _Traits, class _RT>
 106   friend basic_istream<_CharT, _Traits>&
 107   operator>>(basic_istream<_CharT, _Traits>& __is, lognormal_distribution<_RT>& __x);
 108 };
 109
 110 template <class _CharT, class _Traits, class _RT>
 111 inline _LIBCPP_HIDE_FROM_ABI basic_ostream<_CharT, _Traits>&
 112 operator<<(basic_ostream<_CharT, _Traits>& __os, const lognormal_distribution<_RT>& __x) {
 113   return __os << __x.__nd_;
 114 }
 115
 116 template <class _CharT, class _Traits, class _RT>
 117 inline _LIBCPP_HIDE_FROM_ABI basic_istream<_CharT, _Traits>&
 118 operator>>(basic_istream<_CharT, _Traits>& __is, lognormal_distribution<_RT>& __x) {
 119   return __is >> __x.__nd_;
 120 }
 121
 122 _LIBCPP_END_NAMESPACE_STD
 123
 124 _LIBCPP_POP_MACROS
 125
 126 #endif // _LIBCPP___RANDOM_LOGNORMAL_DISTRIBUTION_H