libcxx/include/__random/weibull_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_WEIBULL_DISTRIBUTION_H
  10 #define _LIBCPP___RANDOM_WEIBULL_DISTRIBUTION_H
  11
  12 #include <__config>
  13 #include <__random/exponential_distribution.h>
  14 #include <__random/is_valid.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 weibull_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 __a_;
  39     result_type __b_;
  40
  41   public:
  42     typedef weibull_distribution distribution_type;
  43
  44     _LIBCPP_HIDE_FROM_ABI explicit param_type(result_type __a = 1, result_type __b = 1) : __a_(__a), __b_(__b) {}
  45
  46     _LIBCPP_HIDE_FROM_ABI result_type a() const { return __a_; }
  47     _LIBCPP_HIDE_FROM_ABI result_type b() const { return __b_; }
  48
  49     friend _LIBCPP_HIDE_FROM_ABI bool operator==(const param_type& __x, const param_type& __y) {
  50       return __x.__a_ == __y.__a_ && __x.__b_ == __y.__b_;
  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   param_type __p_;
  57
  58 public:
  59   // constructor and reset functions
  60 #ifndef _LIBCPP_CXX03_LANG
  61   _LIBCPP_HIDE_FROM_ABI weibull_distribution() : weibull_distribution(1) {}
  62   _LIBCPP_HIDE_FROM_ABI explicit weibull_distribution(result_type __a, result_type __b = 1)
  63       : __p_(param_type(__a, __b)) {}
  64 #else
  65   _LIBCPP_HIDE_FROM_ABI explicit weibull_distribution(result_type __a = 1, result_type __b = 1)
  66       : __p_(param_type(__a, __b)) {}
  67 #endif
  68   _LIBCPP_HIDE_FROM_ABI explicit weibull_distribution(const param_type& __p) : __p_(__p) {}
  69   _LIBCPP_HIDE_FROM_ABI void reset() {}
  70
  71   // generating functions
  72   template <class _URNG>
  73   _LIBCPP_HIDE_FROM_ABI result_type operator()(_URNG& __g) {
  74     return (*this)(__g, __p_);
  75   }
  76   template <class _URNG>
  77   _LIBCPP_HIDE_FROM_ABI result_type operator()(_URNG& __g, const param_type& __p) {
  78     return __p.b() * std::pow(exponential_distribution<result_type>()(__g), 1 / __p.a());
  79   }
  80
  81   // property functions
  82   _LIBCPP_HIDE_FROM_ABI result_type a() const { return __p_.a(); }
  83   _LIBCPP_HIDE_FROM_ABI result_type b() const { return __p_.b(); }
  84
  85   _LIBCPP_HIDE_FROM_ABI param_type param() const { return __p_; }
  86   _LIBCPP_HIDE_FROM_ABI void param(const param_type& __p) { __p_ = __p; }
  87
  88   _LIBCPP_HIDE_FROM_ABI result_type min() const { return 0; }
  89   _LIBCPP_HIDE_FROM_ABI result_type max() const { return numeric_limits<result_type>::infinity(); }
  90
  91   friend _LIBCPP_HIDE_FROM_ABI bool operator==(const weibull_distribution& __x, const weibull_distribution& __y) {
  92     return __x.__p_ == __y.__p_;
  93   }
  94   friend _LIBCPP_HIDE_FROM_ABI bool operator!=(const weibull_distribution& __x, const weibull_distribution& __y) {
  95     return !(__x == __y);
  96   }
  97 };
  98
  99 template <class _CharT, class _Traits, class _RT>
 100 _LIBCPP_HIDE_FROM_ABI basic_ostream<_CharT, _Traits>&
 101 operator<<(basic_ostream<_CharT, _Traits>& __os, const weibull_distribution<_RT>& __x) {
 102   __save_flags<_CharT, _Traits> __lx(__os);
 103   typedef basic_ostream<_CharT, _Traits> _OStream;
 104   __os.flags(_OStream::dec | _OStream::left | _OStream::fixed | _OStream::scientific);
 105   _CharT __sp = __os.widen(' ');
 106   __os.fill(__sp);
 107   __os << __x.a() << __sp << __x.b();
 108   return __os;
 109 }
 110
 111 template <class _CharT, class _Traits, class _RT>
 112 _LIBCPP_HIDE_FROM_ABI basic_istream<_CharT, _Traits>&
 113 operator>>(basic_istream<_CharT, _Traits>& __is, weibull_distribution<_RT>& __x) {
 114   typedef weibull_distribution<_RT> _Eng;
 115   typedef typename _Eng::result_type result_type;
 116   typedef typename _Eng::param_type param_type;
 117   __save_flags<_CharT, _Traits> __lx(__is);
 118   typedef basic_istream<_CharT, _Traits> _Istream;
 119   __is.flags(_Istream::dec | _Istream::skipws);
 120   result_type __a;
 121   result_type __b;
 122   __is >> __a >> __b;
 123   if (!__is.fail())
 124     __x.param(param_type(__a, __b));
 125   return __is;
 126 }
 127
 128 _LIBCPP_END_NAMESPACE_STD
 129
 130 _LIBCPP_POP_MACROS
 131
 132 #endif // _LIBCPP___RANDOM_WEIBULL_DISTRIBUTION_H