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_CAUCHY_DISTRIBUTION_H 10 #define _LIBCPP___RANDOM_CAUCHY_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 cauchy_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 cauchy_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 cauchy_distribution() : cauchy_distribution(0) {} 66 _LIBCPP_INLINE_VISIBILITY 67 explicit cauchy_distribution(result_type __a, result_type __b = 1) 68 : __p_(param_type(__a, __b)) {} 69 #else 70 _LIBCPP_INLINE_VISIBILITY 71 explicit cauchy_distribution(result_type __a = 0, result_type __b = 1) 72 : __p_(param_type(__a, __b)) {} 73 #endif 74 _LIBCPP_INLINE_VISIBILITY 75 explicit cauchy_distribution(const param_type& __p) 76 : __p_(__p) {} 77 _LIBCPP_INLINE_VISIBILITY 78 void reset() {} 79 80 // generating functions 81 template<class _URNG> 82 _LIBCPP_INLINE_VISIBILITY 83 result_type operator()(_URNG& __g) 84 {return (*this)(__g, __p_);} 85 template<class _URNG> _LIBCPP_INLINE_VISIBILITY result_type operator()(_URNG& __g, const param_type& __p); 86 87 // property functions 88 _LIBCPP_INLINE_VISIBILITY 89 result_type a() const {return __p_.a();} 90 _LIBCPP_INLINE_VISIBILITY 91 result_type b() const {return __p_.b();} 92 93 _LIBCPP_INLINE_VISIBILITY 94 param_type param() const {return __p_;} 95 _LIBCPP_INLINE_VISIBILITY 96 void param(const param_type& __p) {__p_ = __p;} 97 98 _LIBCPP_INLINE_VISIBILITY 99 result_type min() const {return -numeric_limits<result_type>::infinity();} 100 _LIBCPP_INLINE_VISIBILITY 101 result_type max() const {return numeric_limits<result_type>::infinity();} 102 103 friend _LIBCPP_INLINE_VISIBILITY 104 bool operator==(const cauchy_distribution& __x, 105 const cauchy_distribution& __y) 106 {return __x.__p_ == __y.__p_;} 107 friend _LIBCPP_INLINE_VISIBILITY 108 bool operator!=(const cauchy_distribution& __x, 109 const cauchy_distribution& __y) 110 {return !(__x == __y);} 111 }; 112 113 template <class _RealType> 114 template<class _URNG> 115 inline 116 _RealType 117 cauchy_distribution<_RealType>::operator()(_URNG& __g, const param_type& __p) 118 { 119 uniform_real_distribution<result_type> __gen; 120 // purposefully let tan arg get as close to pi/2 as it wants, tan will return a finite 121 return __p.a() + __p.b() * _VSTD::tan(3.1415926535897932384626433832795 * __gen(__g)); 122 } 123 124 template <class _CharT, class _Traits, class _RT> 125 basic_ostream<_CharT, _Traits>& 126 operator<<(basic_ostream<_CharT, _Traits>& __os, 127 const cauchy_distribution<_RT>& __x) 128 { 129 __save_flags<_CharT, _Traits> __lx(__os); 130 typedef basic_ostream<_CharT, _Traits> _OStream; 131 __os.flags(_OStream::dec | _OStream::left | _OStream::fixed | 132 _OStream::scientific); 133 _CharT __sp = __os.widen(' '); 134 __os.fill(__sp); 135 __os << __x.a() << __sp << __x.b(); 136 return __os; 137 } 138 139 template <class _CharT, class _Traits, class _RT> 140 basic_istream<_CharT, _Traits>& 141 operator>>(basic_istream<_CharT, _Traits>& __is, 142 cauchy_distribution<_RT>& __x) 143 { 144 typedef cauchy_distribution<_RT> _Eng; 145 typedef typename _Eng::result_type result_type; 146 typedef typename _Eng::param_type param_type; 147 __save_flags<_CharT, _Traits> __lx(__is); 148 typedef basic_istream<_CharT, _Traits> _Istream; 149 __is.flags(_Istream::dec | _Istream::skipws); 150 result_type __a; 151 result_type __b; 152 __is >> __a >> __b; 153 if (!__is.fail()) 154 __x.param(param_type(__a, __b)); 155 return __is; 156 } 157 158 _LIBCPP_END_NAMESPACE_STD 159 160 _LIBCPP_POP_MACROS 161 162 #endif // _LIBCPP___RANDOM_CAUCHY_DISTRIBUTION_H 163