14824e7fdSDimitry Andric //===----------------------------------------------------------------------===// 24824e7fdSDimitry Andric // 34824e7fdSDimitry Andric // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 44824e7fdSDimitry Andric // See https://llvm.org/LICENSE.txt for license information. 54824e7fdSDimitry Andric // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 64824e7fdSDimitry Andric // 74824e7fdSDimitry Andric //===----------------------------------------------------------------------===// 84824e7fdSDimitry Andric 94824e7fdSDimitry Andric #ifndef _LIBCPP___RANDOM_EXPONENTIAL_DISTRIBUTION_H 104824e7fdSDimitry Andric #define _LIBCPP___RANDOM_EXPONENTIAL_DISTRIBUTION_H 114824e7fdSDimitry Andric 124824e7fdSDimitry Andric #include <__config> 134824e7fdSDimitry Andric #include <__random/generate_canonical.h> 14*81ad6265SDimitry Andric #include <__random/is_valid.h> 154824e7fdSDimitry Andric #include <__random/uniform_real_distribution.h> 164824e7fdSDimitry Andric #include <cmath> 174824e7fdSDimitry Andric #include <iosfwd> 184824e7fdSDimitry Andric #include <limits> 194824e7fdSDimitry Andric 204824e7fdSDimitry Andric #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 214824e7fdSDimitry Andric # pragma GCC system_header 224824e7fdSDimitry Andric #endif 234824e7fdSDimitry Andric 244824e7fdSDimitry Andric _LIBCPP_PUSH_MACROS 254824e7fdSDimitry Andric #include <__undef_macros> 264824e7fdSDimitry Andric 274824e7fdSDimitry Andric _LIBCPP_BEGIN_NAMESPACE_STD 284824e7fdSDimitry Andric 294824e7fdSDimitry Andric template<class _RealType = double> 304824e7fdSDimitry Andric class _LIBCPP_TEMPLATE_VIS exponential_distribution 314824e7fdSDimitry Andric { 324824e7fdSDimitry Andric public: 334824e7fdSDimitry Andric // types 344824e7fdSDimitry Andric typedef _RealType result_type; 354824e7fdSDimitry Andric 364824e7fdSDimitry Andric class _LIBCPP_TEMPLATE_VIS param_type 374824e7fdSDimitry Andric { 384824e7fdSDimitry Andric result_type __lambda_; 394824e7fdSDimitry Andric public: 404824e7fdSDimitry Andric typedef exponential_distribution distribution_type; 414824e7fdSDimitry Andric 424824e7fdSDimitry Andric _LIBCPP_INLINE_VISIBILITY 434824e7fdSDimitry Andric explicit param_type(result_type __lambda = 1) : __lambda_(__lambda) {} 444824e7fdSDimitry Andric 454824e7fdSDimitry Andric _LIBCPP_INLINE_VISIBILITY 464824e7fdSDimitry Andric result_type lambda() const {return __lambda_;} 474824e7fdSDimitry Andric 484824e7fdSDimitry Andric friend _LIBCPP_INLINE_VISIBILITY 494824e7fdSDimitry Andric bool operator==(const param_type& __x, const param_type& __y) 504824e7fdSDimitry Andric {return __x.__lambda_ == __y.__lambda_;} 514824e7fdSDimitry Andric friend _LIBCPP_INLINE_VISIBILITY 524824e7fdSDimitry Andric bool operator!=(const param_type& __x, const param_type& __y) 534824e7fdSDimitry Andric {return !(__x == __y);} 544824e7fdSDimitry Andric }; 554824e7fdSDimitry Andric 564824e7fdSDimitry Andric private: 574824e7fdSDimitry Andric param_type __p_; 584824e7fdSDimitry Andric 594824e7fdSDimitry Andric public: 604824e7fdSDimitry Andric // constructors and reset functions 614824e7fdSDimitry Andric #ifndef _LIBCPP_CXX03_LANG 624824e7fdSDimitry Andric _LIBCPP_INLINE_VISIBILITY 634824e7fdSDimitry Andric exponential_distribution() : exponential_distribution(1) {} 644824e7fdSDimitry Andric _LIBCPP_INLINE_VISIBILITY 654824e7fdSDimitry Andric explicit exponential_distribution(result_type __lambda) 664824e7fdSDimitry Andric : __p_(param_type(__lambda)) {} 674824e7fdSDimitry Andric #else 684824e7fdSDimitry Andric _LIBCPP_INLINE_VISIBILITY 694824e7fdSDimitry Andric explicit exponential_distribution(result_type __lambda = 1) 704824e7fdSDimitry Andric : __p_(param_type(__lambda)) {} 714824e7fdSDimitry Andric #endif 724824e7fdSDimitry Andric _LIBCPP_INLINE_VISIBILITY 734824e7fdSDimitry Andric explicit exponential_distribution(const param_type& __p) : __p_(__p) {} 744824e7fdSDimitry Andric _LIBCPP_INLINE_VISIBILITY 754824e7fdSDimitry Andric void reset() {} 764824e7fdSDimitry Andric 774824e7fdSDimitry Andric // generating functions 784824e7fdSDimitry Andric template<class _URNG> 794824e7fdSDimitry Andric _LIBCPP_INLINE_VISIBILITY 804824e7fdSDimitry Andric result_type operator()(_URNG& __g) 814824e7fdSDimitry Andric {return (*this)(__g, __p_);} 824824e7fdSDimitry Andric template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p); 834824e7fdSDimitry Andric 844824e7fdSDimitry Andric // property functions 854824e7fdSDimitry Andric _LIBCPP_INLINE_VISIBILITY 864824e7fdSDimitry Andric result_type lambda() const {return __p_.lambda();} 874824e7fdSDimitry Andric 884824e7fdSDimitry Andric _LIBCPP_INLINE_VISIBILITY 894824e7fdSDimitry Andric param_type param() const {return __p_;} 904824e7fdSDimitry Andric _LIBCPP_INLINE_VISIBILITY 914824e7fdSDimitry Andric void param(const param_type& __p) {__p_ = __p;} 924824e7fdSDimitry Andric 934824e7fdSDimitry Andric _LIBCPP_INLINE_VISIBILITY 944824e7fdSDimitry Andric result_type min() const {return 0;} 954824e7fdSDimitry Andric _LIBCPP_INLINE_VISIBILITY 964824e7fdSDimitry Andric result_type max() const {return numeric_limits<result_type>::infinity();} 974824e7fdSDimitry Andric 984824e7fdSDimitry Andric friend _LIBCPP_INLINE_VISIBILITY 994824e7fdSDimitry Andric bool operator==(const exponential_distribution& __x, 1004824e7fdSDimitry Andric const exponential_distribution& __y) 1014824e7fdSDimitry Andric {return __x.__p_ == __y.__p_;} 1024824e7fdSDimitry Andric friend _LIBCPP_INLINE_VISIBILITY 1034824e7fdSDimitry Andric bool operator!=(const exponential_distribution& __x, 1044824e7fdSDimitry Andric const exponential_distribution& __y) 1054824e7fdSDimitry Andric {return !(__x == __y);} 1064824e7fdSDimitry Andric }; 1074824e7fdSDimitry Andric 1084824e7fdSDimitry Andric template <class _RealType> 1094824e7fdSDimitry Andric template<class _URNG> 1104824e7fdSDimitry Andric _RealType 1114824e7fdSDimitry Andric exponential_distribution<_RealType>::operator()(_URNG& __g, const param_type& __p) 1124824e7fdSDimitry Andric { 113*81ad6265SDimitry Andric static_assert(__libcpp_random_is_valid_urng<_URNG>::value, ""); 1144824e7fdSDimitry Andric return -_VSTD::log 1154824e7fdSDimitry Andric ( 1164824e7fdSDimitry Andric result_type(1) - 1174824e7fdSDimitry Andric _VSTD::generate_canonical<result_type, 1184824e7fdSDimitry Andric numeric_limits<result_type>::digits>(__g) 1194824e7fdSDimitry Andric ) 1204824e7fdSDimitry Andric / __p.lambda(); 1214824e7fdSDimitry Andric } 1224824e7fdSDimitry Andric 1234824e7fdSDimitry Andric template <class _CharT, class _Traits, class _RealType> 1244824e7fdSDimitry Andric basic_ostream<_CharT, _Traits>& 1254824e7fdSDimitry Andric operator<<(basic_ostream<_CharT, _Traits>& __os, 1264824e7fdSDimitry Andric const exponential_distribution<_RealType>& __x) 1274824e7fdSDimitry Andric { 1284824e7fdSDimitry Andric __save_flags<_CharT, _Traits> __lx(__os); 1294824e7fdSDimitry Andric typedef basic_ostream<_CharT, _Traits> _OStream; 1304824e7fdSDimitry Andric __os.flags(_OStream::dec | _OStream::left | _OStream::fixed | 1314824e7fdSDimitry Andric _OStream::scientific); 1324824e7fdSDimitry Andric return __os << __x.lambda(); 1334824e7fdSDimitry Andric } 1344824e7fdSDimitry Andric 1354824e7fdSDimitry Andric template <class _CharT, class _Traits, class _RealType> 1364824e7fdSDimitry Andric basic_istream<_CharT, _Traits>& 1374824e7fdSDimitry Andric operator>>(basic_istream<_CharT, _Traits>& __is, 1384824e7fdSDimitry Andric exponential_distribution<_RealType>& __x) 1394824e7fdSDimitry Andric { 1404824e7fdSDimitry Andric typedef exponential_distribution<_RealType> _Eng; 1414824e7fdSDimitry Andric typedef typename _Eng::result_type result_type; 1424824e7fdSDimitry Andric typedef typename _Eng::param_type param_type; 1434824e7fdSDimitry Andric __save_flags<_CharT, _Traits> __lx(__is); 1444824e7fdSDimitry Andric typedef basic_istream<_CharT, _Traits> _Istream; 1454824e7fdSDimitry Andric __is.flags(_Istream::dec | _Istream::skipws); 1464824e7fdSDimitry Andric result_type __lambda; 1474824e7fdSDimitry Andric __is >> __lambda; 1484824e7fdSDimitry Andric if (!__is.fail()) 1494824e7fdSDimitry Andric __x.param(param_type(__lambda)); 1504824e7fdSDimitry Andric return __is; 1514824e7fdSDimitry Andric } 1524824e7fdSDimitry Andric 1534824e7fdSDimitry Andric _LIBCPP_END_NAMESPACE_STD 1544824e7fdSDimitry Andric 1554824e7fdSDimitry Andric _LIBCPP_POP_MACROS 1564824e7fdSDimitry Andric 1574824e7fdSDimitry Andric #endif // _LIBCPP___RANDOM_EXPONENTIAL_DISTRIBUTION_H 158