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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_PIECEWISE_LINEAR_DISTRIBUTION_H10#define _LIBCPP___CXX03___RANDOM_PIECEWISE_LINEAR_DISTRIBUTION_H11 12#include <__cxx03/__algorithm/upper_bound.h>13#include <__cxx03/__config>14#include <__cxx03/__random/is_valid.h>15#include <__cxx03/__random/uniform_real_distribution.h>16#include <__cxx03/cmath>17#include <__cxx03/iosfwd>18#include <__cxx03/vector>19 20#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)21# pragma GCC system_header22#endif23 24_LIBCPP_PUSH_MACROS25#include <__cxx03/__undef_macros>26 27_LIBCPP_BEGIN_NAMESPACE_STD28 29template <class _RealType = double>30class _LIBCPP_TEMPLATE_VIS piecewise_linear_distribution {31 static_assert(__libcpp_random_is_valid_realtype<_RealType>::value,32 "RealType must be a supported floating-point type");33 34public:35 // types36 typedef _RealType result_type;37 38 class _LIBCPP_TEMPLATE_VIS param_type {39 vector<result_type> __b_;40 vector<result_type> __densities_;41 vector<result_type> __areas_;42 43 public:44 typedef piecewise_linear_distribution distribution_type;45 46 _LIBCPP_HIDE_FROM_ABI param_type();47 template <class _InputIteratorB, class _InputIteratorW>48 _LIBCPP_HIDE_FROM_ABI param_type(_InputIteratorB __f_b, _InputIteratorB __l_b, _InputIteratorW __f_w);49 template <class _UnaryOperation>50 _LIBCPP_HIDE_FROM_ABI param_type(size_t __nw, result_type __xmin, result_type __xmax, _UnaryOperation __fw);51 _LIBCPP_HIDE_FROM_ABI param_type(param_type const&) = default;52 _LIBCPP_HIDE_FROM_ABI param_type& operator=(const param_type& __rhs);53 54 _LIBCPP_HIDE_FROM_ABI vector<result_type> intervals() const { return __b_; }55 _LIBCPP_HIDE_FROM_ABI vector<result_type> densities() const { return __densities_; }56 57 friend _LIBCPP_HIDE_FROM_ABI bool operator==(const param_type& __x, const param_type& __y) {58 return __x.__densities_ == __y.__densities_ && __x.__b_ == __y.__b_;59 }60 friend _LIBCPP_HIDE_FROM_ABI bool operator!=(const param_type& __x, const param_type& __y) { return !(__x == __y); }61 62 private:63 _LIBCPP_HIDE_FROM_ABI void __init();64 65 friend class piecewise_linear_distribution;66 67 template <class _CharT, class _Traits, class _RT>68 friend basic_ostream<_CharT, _Traits>&69 operator<<(basic_ostream<_CharT, _Traits>& __os, const piecewise_linear_distribution<_RT>& __x);70 71 template <class _CharT, class _Traits, class _RT>72 friend basic_istream<_CharT, _Traits>&73 operator>>(basic_istream<_CharT, _Traits>& __is, piecewise_linear_distribution<_RT>& __x);74 };75 76private:77 param_type __p_;78 79public:80 // constructor and reset functions81 _LIBCPP_HIDE_FROM_ABI piecewise_linear_distribution() {}82 template <class _InputIteratorB, class _InputIteratorW>83 _LIBCPP_HIDE_FROM_ABI84 piecewise_linear_distribution(_InputIteratorB __f_b, _InputIteratorB __l_b, _InputIteratorW __f_w)85 : __p_(__f_b, __l_b, __f_w) {}86 87 template <class _UnaryOperation>88 _LIBCPP_HIDE_FROM_ABI89 piecewise_linear_distribution(size_t __nw, result_type __xmin, result_type __xmax, _UnaryOperation __fw)90 : __p_(__nw, __xmin, __xmax, __fw) {}91 92 _LIBCPP_HIDE_FROM_ABI explicit piecewise_linear_distribution(const param_type& __p) : __p_(__p) {}93 94 _LIBCPP_HIDE_FROM_ABI void reset() {}95 96 // generating functions97 template <class _URNG>98 _LIBCPP_HIDE_FROM_ABI result_type operator()(_URNG& __g) {99 return (*this)(__g, __p_);100 }101 template <class _URNG>102 _LIBCPP_HIDE_FROM_ABI result_type operator()(_URNG& __g, const param_type& __p);103 104 // property functions105 _LIBCPP_HIDE_FROM_ABI vector<result_type> intervals() const { return __p_.intervals(); }106 _LIBCPP_HIDE_FROM_ABI vector<result_type> densities() const { return __p_.densities(); }107 108 _LIBCPP_HIDE_FROM_ABI param_type param() const { return __p_; }109 _LIBCPP_HIDE_FROM_ABI void param(const param_type& __p) { __p_ = __p; }110 111 _LIBCPP_HIDE_FROM_ABI result_type min() const { return __p_.__b_.front(); }112 _LIBCPP_HIDE_FROM_ABI result_type max() const { return __p_.__b_.back(); }113 114 friend _LIBCPP_HIDE_FROM_ABI bool115 operator==(const piecewise_linear_distribution& __x, const piecewise_linear_distribution& __y) {116 return __x.__p_ == __y.__p_;117 }118 friend _LIBCPP_HIDE_FROM_ABI bool119 operator!=(const piecewise_linear_distribution& __x, const piecewise_linear_distribution& __y) {120 return !(__x == __y);121 }122 123 template <class _CharT, class _Traits, class _RT>124 friend basic_ostream<_CharT, _Traits>&125 operator<<(basic_ostream<_CharT, _Traits>& __os, const piecewise_linear_distribution<_RT>& __x);126 127 template <class _CharT, class _Traits, class _RT>128 friend basic_istream<_CharT, _Traits>&129 operator>>(basic_istream<_CharT, _Traits>& __is, piecewise_linear_distribution<_RT>& __x);130};131 132template <class _RealType>133typename piecewise_linear_distribution<_RealType>::param_type&134piecewise_linear_distribution<_RealType>::param_type::operator=(const param_type& __rhs) {135 // These can throw136 __b_.reserve(__rhs.__b_.size());137 __densities_.reserve(__rhs.__densities_.size());138 __areas_.reserve(__rhs.__areas_.size());139 140 // These can not throw141 __b_ = __rhs.__b_;142 __densities_ = __rhs.__densities_;143 __areas_ = __rhs.__areas_;144 return *this;145}146 147template <class _RealType>148void piecewise_linear_distribution<_RealType>::param_type::__init() {149 __areas_.assign(__densities_.size() - 1, result_type());150 result_type __sp = 0;151 for (size_t __i = 0; __i < __areas_.size(); ++__i) {152 __areas_[__i] = (__densities_[__i + 1] + __densities_[__i]) * (__b_[__i + 1] - __b_[__i]) * .5;153 __sp += __areas_[__i];154 }155 for (size_t __i = __areas_.size(); __i > 1;) {156 --__i;157 __areas_[__i] = __areas_[__i - 1] / __sp;158 }159 __areas_[0] = 0;160 for (size_t __i = 1; __i < __areas_.size(); ++__i)161 __areas_[__i] += __areas_[__i - 1];162 for (size_t __i = 0; __i < __densities_.size(); ++__i)163 __densities_[__i] /= __sp;164}165 166template <class _RealType>167piecewise_linear_distribution<_RealType>::param_type::param_type() : __b_(2), __densities_(2, 1.0), __areas_(1, 0.0) {168 __b_[1] = 1;169}170 171template <class _RealType>172template <class _InputIteratorB, class _InputIteratorW>173piecewise_linear_distribution<_RealType>::param_type::param_type(174 _InputIteratorB __f_b, _InputIteratorB __l_b, _InputIteratorW __f_w)175 : __b_(__f_b, __l_b) {176 if (__b_.size() < 2) {177 __b_.resize(2);178 __b_[0] = 0;179 __b_[1] = 1;180 __densities_.assign(2, 1.0);181 __areas_.assign(1, 0.0);182 } else {183 __densities_.reserve(__b_.size());184 for (size_t __i = 0; __i < __b_.size(); ++__i, ++__f_w)185 __densities_.push_back(*__f_w);186 __init();187 }188}189 190template <class _RealType>191template <class _UnaryOperation>192piecewise_linear_distribution<_RealType>::param_type::param_type(193 size_t __nw, result_type __xmin, result_type __xmax, _UnaryOperation __fw)194 : __b_(__nw == 0 ? 2 : __nw + 1) {195 size_t __n = __b_.size() - 1;196 result_type __d = (__xmax - __xmin) / __n;197 __densities_.reserve(__b_.size());198 for (size_t __i = 0; __i < __n; ++__i) {199 __b_[__i] = __xmin + __i * __d;200 __densities_.push_back(__fw(__b_[__i]));201 }202 __b_[__n] = __xmax;203 __densities_.push_back(__fw(__b_[__n]));204 __init();205}206 207template <class _RealType>208template <class _URNG>209_RealType piecewise_linear_distribution<_RealType>::operator()(_URNG& __g, const param_type& __p) {210 static_assert(__libcpp_random_is_valid_urng<_URNG>::value, "");211 typedef uniform_real_distribution<result_type> _Gen;212 result_type __u = _Gen()(__g);213 ptrdiff_t __k = std::upper_bound(__p.__areas_.begin(), __p.__areas_.end(), __u) - __p.__areas_.begin() - 1;214 __u -= __p.__areas_[__k];215 const result_type __dk = __p.__densities_[__k];216 const result_type __dk1 = __p.__densities_[__k + 1];217 const result_type __deltad = __dk1 - __dk;218 const result_type __bk = __p.__b_[__k];219 if (__deltad == 0)220 return __u / __dk + __bk;221 const result_type __bk1 = __p.__b_[__k + 1];222 const result_type __deltab = __bk1 - __bk;223 return (__bk * __dk1 - __bk1 * __dk + std::sqrt(__deltab * (__deltab * __dk * __dk + 2 * __deltad * __u))) / __deltad;224}225 226template <class _CharT, class _Traits, class _RT>227_LIBCPP_HIDE_FROM_ABI basic_ostream<_CharT, _Traits>&228operator<<(basic_ostream<_CharT, _Traits>& __os, const piecewise_linear_distribution<_RT>& __x) {229 __save_flags<_CharT, _Traits> __lx(__os);230 typedef basic_ostream<_CharT, _Traits> _OStream;231 __os.flags(_OStream::dec | _OStream::left | _OStream::fixed | _OStream::scientific);232 _CharT __sp = __os.widen(' ');233 __os.fill(__sp);234 size_t __n = __x.__p_.__b_.size();235 __os << __n;236 for (size_t __i = 0; __i < __n; ++__i)237 __os << __sp << __x.__p_.__b_[__i];238 __n = __x.__p_.__densities_.size();239 __os << __sp << __n;240 for (size_t __i = 0; __i < __n; ++__i)241 __os << __sp << __x.__p_.__densities_[__i];242 __n = __x.__p_.__areas_.size();243 __os << __sp << __n;244 for (size_t __i = 0; __i < __n; ++__i)245 __os << __sp << __x.__p_.__areas_[__i];246 return __os;247}248 249template <class _CharT, class _Traits, class _RT>250_LIBCPP_HIDE_FROM_ABI basic_istream<_CharT, _Traits>&251operator>>(basic_istream<_CharT, _Traits>& __is, piecewise_linear_distribution<_RT>& __x) {252 typedef piecewise_linear_distribution<_RT> _Eng;253 typedef typename _Eng::result_type result_type;254 __save_flags<_CharT, _Traits> __lx(__is);255 typedef basic_istream<_CharT, _Traits> _Istream;256 __is.flags(_Istream::dec | _Istream::skipws);257 size_t __n;258 __is >> __n;259 vector<result_type> __b(__n);260 for (size_t __i = 0; __i < __n; ++__i)261 __is >> __b[__i];262 __is >> __n;263 vector<result_type> __densities(__n);264 for (size_t __i = 0; __i < __n; ++__i)265 __is >> __densities[__i];266 __is >> __n;267 vector<result_type> __areas(__n);268 for (size_t __i = 0; __i < __n; ++__i)269 __is >> __areas[__i];270 if (!__is.fail()) {271 swap(__x.__p_.__b_, __b);272 swap(__x.__p_.__densities_, __densities);273 swap(__x.__p_.__areas_, __areas);274 }275 return __is;276}277 278_LIBCPP_END_NAMESPACE_STD279 280_LIBCPP_POP_MACROS281 282#endif // _LIBCPP___CXX03___RANDOM_PIECEWISE_LINEAR_DISTRIBUTION_H283