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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-exception6//7//===----------------------------------------------------------------------===//8 9#ifndef _LIBCPP___CXX03___RANDOM_CAUCHY_DISTRIBUTION_H10#define _LIBCPP___CXX03___RANDOM_CAUCHY_DISTRIBUTION_H11 12#include <__cxx03/__config>13#include <__cxx03/__random/is_valid.h>14#include <__cxx03/__random/uniform_real_distribution.h>15#include <__cxx03/cmath>16#include <__cxx03/iosfwd>17#include <__cxx03/limits>18 19#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)20# pragma GCC system_header21#endif22 23_LIBCPP_PUSH_MACROS24#include <__cxx03/__undef_macros>25 26_LIBCPP_BEGIN_NAMESPACE_STD27 28template <class _RealType = double>29class _LIBCPP_TEMPLATE_VIS cauchy_distribution {30 static_assert(__libcpp_random_is_valid_realtype<_RealType>::value,31 "RealType must be a supported floating-point type");32 33public:34 // types35 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 cauchy_distribution distribution_type;43 44 _LIBCPP_HIDE_FROM_ABI explicit param_type(result_type __a = 0, 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 functions60 _LIBCPP_HIDE_FROM_ABI explicit cauchy_distribution(result_type __a = 0, result_type __b = 1)61 : __p_(param_type(__a, __b)) {}62 _LIBCPP_HIDE_FROM_ABI explicit cauchy_distribution(const param_type& __p) : __p_(__p) {}63 _LIBCPP_HIDE_FROM_ABI void reset() {}64 65 // generating functions66 template <class _URNG>67 _LIBCPP_HIDE_FROM_ABI result_type operator()(_URNG& __g) {68 return (*this)(__g, __p_);69 }70 template <class _URNG>71 _LIBCPP_HIDE_FROM_ABI result_type operator()(_URNG& __g, const param_type& __p);72 73 // property functions74 _LIBCPP_HIDE_FROM_ABI result_type a() const { return __p_.a(); }75 _LIBCPP_HIDE_FROM_ABI result_type b() const { return __p_.b(); }76 77 _LIBCPP_HIDE_FROM_ABI param_type param() const { return __p_; }78 _LIBCPP_HIDE_FROM_ABI void param(const param_type& __p) { __p_ = __p; }79 80 _LIBCPP_HIDE_FROM_ABI result_type min() const { return -numeric_limits<result_type>::infinity(); }81 _LIBCPP_HIDE_FROM_ABI result_type max() const { return numeric_limits<result_type>::infinity(); }82 83 friend _LIBCPP_HIDE_FROM_ABI bool operator==(const cauchy_distribution& __x, const cauchy_distribution& __y) {84 return __x.__p_ == __y.__p_;85 }86 friend _LIBCPP_HIDE_FROM_ABI bool operator!=(const cauchy_distribution& __x, const cauchy_distribution& __y) {87 return !(__x == __y);88 }89};90 91template <class _RealType>92template <class _URNG>93inline _RealType cauchy_distribution<_RealType>::operator()(_URNG& __g, const param_type& __p) {94 static_assert(__libcpp_random_is_valid_urng<_URNG>::value, "");95 uniform_real_distribution<result_type> __gen;96 // purposefully let tan arg get as close to pi/2 as it wants, tan will return a finite97 return __p.a() + __p.b() * std::tan(3.1415926535897932384626433832795 * __gen(__g));98}99 100template <class _CharT, class _Traits, class _RT>101_LIBCPP_HIDE_FROM_ABI basic_ostream<_CharT, _Traits>&102operator<<(basic_ostream<_CharT, _Traits>& __os, const cauchy_distribution<_RT>& __x) {103 __save_flags<_CharT, _Traits> __lx(__os);104 typedef basic_ostream<_CharT, _Traits> _OStream;105 __os.flags(_OStream::dec | _OStream::left | _OStream::fixed | _OStream::scientific);106 _CharT __sp = __os.widen(' ');107 __os.fill(__sp);108 __os << __x.a() << __sp << __x.b();109 return __os;110}111 112template <class _CharT, class _Traits, class _RT>113_LIBCPP_HIDE_FROM_ABI basic_istream<_CharT, _Traits>&114operator>>(basic_istream<_CharT, _Traits>& __is, cauchy_distribution<_RT>& __x) {115 typedef cauchy_distribution<_RT> _Eng;116 typedef typename _Eng::result_type result_type;117 typedef typename _Eng::param_type param_type;118 __save_flags<_CharT, _Traits> __lx(__is);119 typedef basic_istream<_CharT, _Traits> _Istream;120 __is.flags(_Istream::dec | _Istream::skipws);121 result_type __a;122 result_type __b;123 __is >> __a >> __b;124 if (!__is.fail())125 __x.param(param_type(__a, __b));126 return __is;127}128 129_LIBCPP_END_NAMESPACE_STD130 131_LIBCPP_POP_MACROS132 133#endif // _LIBCPP___CXX03___RANDOM_CAUCHY_DISTRIBUTION_H134