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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___RANDOM_CAUCHY_DISTRIBUTION_H10#define _LIBCPP___RANDOM_CAUCHY_DISTRIBUTION_H11 12#include <__config>13#include <__random/is_valid.h>14#include <__random/uniform_real_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_header21#endif22 23_LIBCPP_PUSH_MACROS24#include <__undef_macros>25 26_LIBCPP_BEGIN_NAMESPACE_STD27 28template <class _RealType = double>29class 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 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#ifndef _LIBCPP_CXX03_LANG61 _LIBCPP_HIDE_FROM_ABI cauchy_distribution() : cauchy_distribution(0) {}62 _LIBCPP_HIDE_FROM_ABI explicit cauchy_distribution(result_type __a, result_type __b = 1)63 : __p_(param_type(__a, __b)) {}64#else65 _LIBCPP_HIDE_FROM_ABI explicit cauchy_distribution(result_type __a = 0, result_type __b = 1)66 : __p_(param_type(__a, __b)) {}67#endif68 _LIBCPP_HIDE_FROM_ABI explicit cauchy_distribution(const param_type& __p) : __p_(__p) {}69 _LIBCPP_HIDE_FROM_ABI void reset() {}70 71 // generating functions72 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 79 // property functions80 _LIBCPP_HIDE_FROM_ABI result_type a() const { return __p_.a(); }81 _LIBCPP_HIDE_FROM_ABI result_type b() const { return __p_.b(); }82 83 _LIBCPP_HIDE_FROM_ABI param_type param() const { return __p_; }84 _LIBCPP_HIDE_FROM_ABI void param(const param_type& __p) { __p_ = __p; }85 86 _LIBCPP_HIDE_FROM_ABI result_type min() const { return -numeric_limits<result_type>::infinity(); }87 _LIBCPP_HIDE_FROM_ABI result_type max() const { return numeric_limits<result_type>::infinity(); }88 89 friend _LIBCPP_HIDE_FROM_ABI bool operator==(const cauchy_distribution& __x, const cauchy_distribution& __y) {90 return __x.__p_ == __y.__p_;91 }92 friend _LIBCPP_HIDE_FROM_ABI bool operator!=(const cauchy_distribution& __x, const cauchy_distribution& __y) {93 return !(__x == __y);94 }95};96 97template <class _RealType>98template <class _URNG>99inline _RealType cauchy_distribution<_RealType>::operator()(_URNG& __g, const param_type& __p) {100 static_assert(__libcpp_random_is_valid_urng<_URNG>::value, "");101 uniform_real_distribution<result_type> __gen;102 // purposefully let tan arg get as close to pi/2 as it wants, tan will return a finite103 return __p.a() + __p.b() * std::tan(3.1415926535897932384626433832795 * __gen(__g));104}105 106template <class _CharT, class _Traits, class _RT>107_LIBCPP_HIDE_FROM_ABI basic_ostream<_CharT, _Traits>&108operator<<(basic_ostream<_CharT, _Traits>& __os, const cauchy_distribution<_RT>& __x) {109 __save_flags<_CharT, _Traits> __lx(__os);110 typedef basic_ostream<_CharT, _Traits> _OStream;111 __os.flags(_OStream::dec | _OStream::left | _OStream::fixed | _OStream::scientific);112 _CharT __sp = __os.widen(' ');113 __os.fill(__sp);114 __os << __x.a() << __sp << __x.b();115 return __os;116}117 118template <class _CharT, class _Traits, class _RT>119_LIBCPP_HIDE_FROM_ABI basic_istream<_CharT, _Traits>&120operator>>(basic_istream<_CharT, _Traits>& __is, cauchy_distribution<_RT>& __x) {121 typedef cauchy_distribution<_RT> _Eng;122 typedef typename _Eng::result_type result_type;123 typedef typename _Eng::param_type param_type;124 __save_flags<_CharT, _Traits> __lx(__is);125 typedef basic_istream<_CharT, _Traits> _Istream;126 __is.flags(_Istream::dec | _Istream::skipws);127 result_type __a;128 result_type __b;129 __is >> __a >> __b;130 if (!__is.fail())131 __x.param(param_type(__a, __b));132 return __is;133}134 135_LIBCPP_END_NAMESPACE_STD136 137_LIBCPP_POP_MACROS138 139#endif // _LIBCPP___RANDOM_CAUCHY_DISTRIBUTION_H140