v1/__random/lognormal_distribution.h

0001 //===----------------------------------------------------------------------===//
0002 //
0003 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
0004 // See https://llvm.org/LICENSE.txt for license information.
0005 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
0006 //
0007 //===----------------------------------------------------------------------===//
0008
0009 #ifndef _LIBCPP___RANDOM_LOGNORMAL_DISTRIBUTION_H
0010 #define _LIBCPP___RANDOM_LOGNORMAL_DISTRIBUTION_H
0011
0012 #include <__config>
0013 #include <__random/is_valid.h>
0014 #include <__random/normal_distribution.h>
0015 #include <cmath>
0016 #include <iosfwd>
0017 #include <limits>
0018
0019 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
0020 #  pragma GCC system_header
0021 #endif
0022
0023 _LIBCPP_PUSH_MACROS
0024 #include <__undef_macros>
0025
0026 _LIBCPP_BEGIN_NAMESPACE_STD
0027
0028 template <class _RealType = double>
0029 class _LIBCPP_TEMPLATE_VIS lognormal_distribution {
0030   static_assert(__libcpp_random_is_valid_realtype<_RealType>::value,
0031                 "RealType must be a supported floating-point type");
0032
0033 public:
0034   // types
0035   typedef _RealType result_type;
0036
0037   class _LIBCPP_TEMPLATE_VIS param_type {
0038     result_type __m_;
0039     result_type __s_;
0040
0041   public:
0042     typedef lognormal_distribution distribution_type;
0043
0044     _LIBCPP_HIDE_FROM_ABI explicit param_type(result_type __m = 0, result_type __s = 1) : __m_(__m), __s_(__s) {}
0045
0046     _LIBCPP_HIDE_FROM_ABI result_type m() const { return __m_; }
0047     _LIBCPP_HIDE_FROM_ABI result_type s() const { return __s_; }
0048
0049     friend _LIBCPP_HIDE_FROM_ABI bool operator==(const param_type& __x, const param_type& __y) {
0050       return __x.__m_ == __y.__m_ && __x.__s_ == __y.__s_;
0051     }
0052     friend _LIBCPP_HIDE_FROM_ABI bool operator!=(const param_type& __x, const param_type& __y) { return !(__x == __y); }
0053   };
0054
0055 private:
0056   normal_distribution<result_type> __nd_;
0057
0058 public:
0059   // constructor and reset functions
0060 #ifndef _LIBCPP_CXX03_LANG
0061   _LIBCPP_HIDE_FROM_ABI lognormal_distribution() : lognormal_distribution(0) {}
0062   _LIBCPP_HIDE_FROM_ABI explicit lognormal_distribution(result_type __m, result_type __s = 1) : __nd_(__m, __s) {}
0063 #else
0064   _LIBCPP_HIDE_FROM_ABI explicit lognormal_distribution(result_type __m = 0, result_type __s = 1) : __nd_(__m, __s) {}
0065 #endif
0066   _LIBCPP_HIDE_FROM_ABI explicit lognormal_distribution(const param_type& __p) : __nd_(__p.m(), __p.s()) {}
0067   _LIBCPP_HIDE_FROM_ABI void reset() { __nd_.reset(); }
0068
0069   // generating functions
0070   template <class _URNG>
0071   _LIBCPP_HIDE_FROM_ABI result_type operator()(_URNG& __g) {
0072     return std::exp(__nd_(__g));
0073   }
0074
0075   template <class _URNG>
0076   _LIBCPP_HIDE_FROM_ABI result_type operator()(_URNG& __g, const param_type& __p) {
0077     typename normal_distribution<result_type>::param_type __pn(__p.m(), __p.s());
0078     return std::exp(__nd_(__g, __pn));
0079   }
0080
0081   // property functions
0082   _LIBCPP_HIDE_FROM_ABI result_type m() const { return __nd_.mean(); }
0083   _LIBCPP_HIDE_FROM_ABI result_type s() const { return __nd_.stddev(); }
0084
0085   _LIBCPP_HIDE_FROM_ABI param_type param() const { return param_type(__nd_.mean(), __nd_.stddev()); }
0086   _LIBCPP_HIDE_FROM_ABI void param(const param_type& __p) {
0087     typename normal_distribution<result_type>::param_type __pn(__p.m(), __p.s());
0088     __nd_.param(__pn);
0089   }
0090
0091   _LIBCPP_HIDE_FROM_ABI result_type min() const { return 0; }
0092   _LIBCPP_HIDE_FROM_ABI result_type max() const { return numeric_limits<result_type>::infinity(); }
0093
0094   friend _LIBCPP_HIDE_FROM_ABI bool operator==(const lognormal_distribution& __x, const lognormal_distribution& __y) {
0095     return __x.__nd_ == __y.__nd_;
0096   }
0097   friend _LIBCPP_HIDE_FROM_ABI bool operator!=(const lognormal_distribution& __x, const lognormal_distribution& __y) {
0098     return !(__x == __y);
0099   }
0100
0101   template <class _CharT, class _Traits, class _RT>
0102   friend basic_ostream<_CharT, _Traits>&
0103   operator<<(basic_ostream<_CharT, _Traits>& __os, const lognormal_distribution<_RT>& __x);
0104
0105   template <class _CharT, class _Traits, class _RT>
0106   friend basic_istream<_CharT, _Traits>&
0107   operator>>(basic_istream<_CharT, _Traits>& __is, lognormal_distribution<_RT>& __x);
0108 };
0109
0110 template <class _CharT, class _Traits, class _RT>
0111 inline _LIBCPP_HIDE_FROM_ABI basic_ostream<_CharT, _Traits>&
0112 operator<<(basic_ostream<_CharT, _Traits>& __os, const lognormal_distribution<_RT>& __x) {
0113   return __os << __x.__nd_;
0114 }
0115
0116 template <class _CharT, class _Traits, class _RT>
0117 inline _LIBCPP_HIDE_FROM_ABI basic_istream<_CharT, _Traits>&
0118 operator>>(basic_istream<_CharT, _Traits>& __is, lognormal_distribution<_RT>& __x) {
0119   return __is >> __x.__nd_;
0120 }
0121
0122 _LIBCPP_END_NAMESPACE_STD
0123
0124 _LIBCPP_POP_MACROS
0125
0126 #endif // _LIBCPP___RANDOM_LOGNORMAL_DISTRIBUTION_H