| //===----------------------------------------------------------------------===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef _LIBCPP___RANDOM_NORMAL_DISTRIBUTION_H |
| #define _LIBCPP___RANDOM_NORMAL_DISTRIBUTION_H |
| |
| #include <__config> |
| #include <__random/is_valid.h> |
| #include <__random/uniform_real_distribution.h> |
| #include <cmath> |
| #include <iosfwd> |
| #include <limits> |
| |
| #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) |
| # pragma GCC system_header |
| #endif |
| |
| _LIBCPP_PUSH_MACROS |
| #include <__undef_macros> |
| |
| _LIBCPP_BEGIN_NAMESPACE_STD |
| |
| template <class _RealType = double> |
| class _LIBCPP_TEMPLATE_VIS normal_distribution { |
| static_assert(__libcpp_random_is_valid_realtype<_RealType>::value, |
| "RealType must be a supported floating-point type"); |
| |
| public: |
| // types |
| typedef _RealType result_type; |
| |
| class _LIBCPP_TEMPLATE_VIS param_type { |
| result_type __mean_; |
| result_type __stddev_; |
| |
| public: |
| typedef normal_distribution distribution_type; |
| |
| _LIBCPP_HIDE_FROM_ABI explicit param_type(result_type __mean = 0, result_type __stddev = 1) |
| : __mean_(__mean), __stddev_(__stddev) {} |
| |
| _LIBCPP_HIDE_FROM_ABI result_type mean() const { return __mean_; } |
| _LIBCPP_HIDE_FROM_ABI result_type stddev() const { return __stddev_; } |
| |
| friend _LIBCPP_HIDE_FROM_ABI bool operator==(const param_type& __x, const param_type& __y) { |
| return __x.__mean_ == __y.__mean_ && __x.__stddev_ == __y.__stddev_; |
| } |
| friend _LIBCPP_HIDE_FROM_ABI bool operator!=(const param_type& __x, const param_type& __y) { return !(__x == __y); } |
| }; |
| |
| private: |
| param_type __p_; |
| result_type __v_; |
| bool __v_hot_; |
| |
| public: |
| // constructors and reset functions |
| #ifndef _LIBCPP_CXX03_LANG |
| _LIBCPP_HIDE_FROM_ABI normal_distribution() : normal_distribution(0) {} |
| _LIBCPP_HIDE_FROM_ABI explicit normal_distribution(result_type __mean, result_type __stddev = 1) |
| : __p_(param_type(__mean, __stddev)), __v_hot_(false) {} |
| #else |
| _LIBCPP_HIDE_FROM_ABI explicit normal_distribution(result_type __mean = 0, result_type __stddev = 1) |
| : __p_(param_type(__mean, __stddev)), __v_hot_(false) {} |
| #endif |
| _LIBCPP_HIDE_FROM_ABI explicit normal_distribution(const param_type& __p) : __p_(__p), __v_hot_(false) {} |
| _LIBCPP_HIDE_FROM_ABI void reset() { __v_hot_ = false; } |
| |
| // generating functions |
| template <class _URNG> |
| _LIBCPP_HIDE_FROM_ABI result_type operator()(_URNG& __g) { |
| return (*this)(__g, __p_); |
| } |
| template <class _URNG> |
| _LIBCPP_HIDE_FROM_ABI result_type operator()(_URNG& __g, const param_type& __p); |
| |
| // property functions |
| _LIBCPP_HIDE_FROM_ABI result_type mean() const { return __p_.mean(); } |
| _LIBCPP_HIDE_FROM_ABI result_type stddev() const { return __p_.stddev(); } |
| |
| _LIBCPP_HIDE_FROM_ABI param_type param() const { return __p_; } |
| _LIBCPP_HIDE_FROM_ABI void param(const param_type& __p) { __p_ = __p; } |
| |
| _LIBCPP_HIDE_FROM_ABI result_type min() const { return -numeric_limits<result_type>::infinity(); } |
| _LIBCPP_HIDE_FROM_ABI result_type max() const { return numeric_limits<result_type>::infinity(); } |
| |
| friend _LIBCPP_HIDE_FROM_ABI bool operator==(const normal_distribution& __x, const normal_distribution& __y) { |
| return __x.__p_ == __y.__p_ && __x.__v_hot_ == __y.__v_hot_ && (!__x.__v_hot_ || __x.__v_ == __y.__v_); |
| } |
| friend _LIBCPP_HIDE_FROM_ABI bool operator!=(const normal_distribution& __x, const normal_distribution& __y) { |
| return !(__x == __y); |
| } |
| |
| template <class _CharT, class _Traits, class _RT> |
| friend basic_ostream<_CharT, _Traits>& |
| operator<<(basic_ostream<_CharT, _Traits>& __os, const normal_distribution<_RT>& __x); |
| |
| template <class _CharT, class _Traits, class _RT> |
| friend basic_istream<_CharT, _Traits>& |
| operator>>(basic_istream<_CharT, _Traits>& __is, normal_distribution<_RT>& __x); |
| }; |
| |
| template <class _RealType> |
| template <class _URNG> |
| _RealType normal_distribution<_RealType>::operator()(_URNG& __g, const param_type& __p) { |
| static_assert(__libcpp_random_is_valid_urng<_URNG>::value, ""); |
| result_type __up; |
| if (__v_hot_) { |
| __v_hot_ = false; |
| __up = __v_; |
| } else { |
| uniform_real_distribution<result_type> __uni(-1, 1); |
| result_type __u; |
| result_type __v; |
| result_type __s; |
| do { |
| __u = __uni(__g); |
| __v = __uni(__g); |
| __s = __u * __u + __v * __v; |
| } while (__s > 1 || __s == 0); |
| result_type __fp = std::sqrt(-2 * std::log(__s) / __s); |
| __v_ = __v * __fp; |
| __v_hot_ = true; |
| __up = __u * __fp; |
| } |
| return __up * __p.stddev() + __p.mean(); |
| } |
| |
| template <class _CharT, class _Traits, class _RT> |
| _LIBCPP_HIDE_FROM_ABI basic_ostream<_CharT, _Traits>& |
| operator<<(basic_ostream<_CharT, _Traits>& __os, const normal_distribution<_RT>& __x) { |
| __save_flags<_CharT, _Traits> __lx(__os); |
| typedef basic_ostream<_CharT, _Traits> _OStream; |
| __os.flags(_OStream::dec | _OStream::left | _OStream::fixed | _OStream::scientific); |
| _CharT __sp = __os.widen(' '); |
| __os.fill(__sp); |
| __os << __x.mean() << __sp << __x.stddev() << __sp << __x.__v_hot_; |
| if (__x.__v_hot_) |
| __os << __sp << __x.__v_; |
| return __os; |
| } |
| |
| template <class _CharT, class _Traits, class _RT> |
| _LIBCPP_HIDE_FROM_ABI basic_istream<_CharT, _Traits>& |
| operator>>(basic_istream<_CharT, _Traits>& __is, normal_distribution<_RT>& __x) { |
| typedef normal_distribution<_RT> _Eng; |
| typedef typename _Eng::result_type result_type; |
| typedef typename _Eng::param_type param_type; |
| __save_flags<_CharT, _Traits> __lx(__is); |
| typedef basic_istream<_CharT, _Traits> _Istream; |
| __is.flags(_Istream::dec | _Istream::skipws); |
| result_type __mean; |
| result_type __stddev; |
| result_type __vp = 0; |
| bool __v_hot = false; |
| __is >> __mean >> __stddev >> __v_hot; |
| if (__v_hot) |
| __is >> __vp; |
| if (!__is.fail()) { |
| __x.param(param_type(__mean, __stddev)); |
| __x.__v_hot_ = __v_hot; |
| __x.__v_ = __vp; |
| } |
| return __is; |
| } |
| |
| _LIBCPP_END_NAMESPACE_STD |
| |
| _LIBCPP_POP_MACROS |
| |
| #endif // _LIBCPP___RANDOM_NORMAL_DISTRIBUTION_H |