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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
28template <class _RealType = double>
29class weibull_distribution {
30 static_assert(__libcpp_random_is_valid_realtype<_RealType>::value,
31 "RealType must be a supported floating-point type");
32
33public:
34 // types
35 typedef _RealType result_type;
36
37 class 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
55private:
56 param_type __p_;
57
58public:
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
99template <class _CharT, class _Traits, class _RT>
100_LIBCPP_HIDE_FROM_ABI basic_ostream<_CharT, _Traits>&
101operator<<(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
111template <class _CharT, class _Traits, class _RT>
112_LIBCPP_HIDE_FROM_ABI basic_istream<_CharT, _Traits>&
113operator>>(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