| //===----------------------------------------------------------------------===// |
| // |
| // 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_PIECEWISE_CONSTANT_DISTRIBUTION_H |
| #define _LIBCPP___RANDOM_PIECEWISE_CONSTANT_DISTRIBUTION_H |
| |
| #include <__algorithm/upper_bound.h> |
| #include <__config> |
| #include <__random/uniform_real_distribution.h> |
| #include <iosfwd> |
| #include <numeric> |
| #include <vector> |
| |
| #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 piecewise_constant_distribution |
| { |
| public: |
| // types |
| typedef _RealType result_type; |
| |
| class _LIBCPP_TEMPLATE_VIS param_type |
| { |
| vector<result_type> __b_; |
| vector<result_type> __densities_; |
| vector<result_type> __areas_; |
| public: |
| typedef piecewise_constant_distribution distribution_type; |
| |
| param_type(); |
| template<class _InputIteratorB, class _InputIteratorW> |
| param_type(_InputIteratorB __fB, _InputIteratorB __lB, |
| _InputIteratorW __fW); |
| #ifndef _LIBCPP_CXX03_LANG |
| template<class _UnaryOperation> |
| param_type(initializer_list<result_type> __bl, _UnaryOperation __fw); |
| #endif // _LIBCPP_CXX03_LANG |
| template<class _UnaryOperation> |
| param_type(size_t __nw, result_type __xmin, result_type __xmax, |
| _UnaryOperation __fw); |
| param_type(param_type const&) = default; |
| param_type & operator=(const param_type& __rhs); |
| |
| _LIBCPP_INLINE_VISIBILITY |
| vector<result_type> intervals() const {return __b_;} |
| _LIBCPP_INLINE_VISIBILITY |
| vector<result_type> densities() const {return __densities_;} |
| |
| friend _LIBCPP_INLINE_VISIBILITY |
| bool operator==(const param_type& __x, const param_type& __y) |
| {return __x.__densities_ == __y.__densities_ && __x.__b_ == __y.__b_;} |
| friend _LIBCPP_INLINE_VISIBILITY |
| bool operator!=(const param_type& __x, const param_type& __y) |
| {return !(__x == __y);} |
| |
| private: |
| void __init(); |
| |
| friend class piecewise_constant_distribution; |
| |
| template <class _CharT, class _Traits, class _RT> |
| friend |
| basic_ostream<_CharT, _Traits>& |
| operator<<(basic_ostream<_CharT, _Traits>& __os, |
| const piecewise_constant_distribution<_RT>& __x); |
| |
| template <class _CharT, class _Traits, class _RT> |
| friend |
| basic_istream<_CharT, _Traits>& |
| operator>>(basic_istream<_CharT, _Traits>& __is, |
| piecewise_constant_distribution<_RT>& __x); |
| }; |
| |
| private: |
| param_type __p_; |
| |
| public: |
| // constructor and reset functions |
| _LIBCPP_INLINE_VISIBILITY |
| piecewise_constant_distribution() {} |
| template<class _InputIteratorB, class _InputIteratorW> |
| _LIBCPP_INLINE_VISIBILITY |
| piecewise_constant_distribution(_InputIteratorB __fB, |
| _InputIteratorB __lB, |
| _InputIteratorW __fW) |
| : __p_(__fB, __lB, __fW) {} |
| |
| #ifndef _LIBCPP_CXX03_LANG |
| template<class _UnaryOperation> |
| _LIBCPP_INLINE_VISIBILITY |
| piecewise_constant_distribution(initializer_list<result_type> __bl, |
| _UnaryOperation __fw) |
| : __p_(__bl, __fw) {} |
| #endif // _LIBCPP_CXX03_LANG |
| |
| template<class _UnaryOperation> |
| _LIBCPP_INLINE_VISIBILITY |
| piecewise_constant_distribution(size_t __nw, result_type __xmin, |
| result_type __xmax, _UnaryOperation __fw) |
| : __p_(__nw, __xmin, __xmax, __fw) {} |
| |
| _LIBCPP_INLINE_VISIBILITY |
| explicit piecewise_constant_distribution(const param_type& __p) |
| : __p_(__p) {} |
| |
| _LIBCPP_INLINE_VISIBILITY |
| void reset() {} |
| |
| // generating functions |
| template<class _URNG> |
| _LIBCPP_INLINE_VISIBILITY |
| result_type operator()(_URNG& __g) |
| {return (*this)(__g, __p_);} |
| template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p); |
| |
| // property functions |
| _LIBCPP_INLINE_VISIBILITY |
| vector<result_type> intervals() const {return __p_.intervals();} |
| _LIBCPP_INLINE_VISIBILITY |
| vector<result_type> densities() const {return __p_.densities();} |
| |
| _LIBCPP_INLINE_VISIBILITY |
| param_type param() const {return __p_;} |
| _LIBCPP_INLINE_VISIBILITY |
| void param(const param_type& __p) {__p_ = __p;} |
| |
| _LIBCPP_INLINE_VISIBILITY |
| result_type min() const {return __p_.__b_.front();} |
| _LIBCPP_INLINE_VISIBILITY |
| result_type max() const {return __p_.__b_.back();} |
| |
| friend _LIBCPP_INLINE_VISIBILITY |
| bool operator==(const piecewise_constant_distribution& __x, |
| const piecewise_constant_distribution& __y) |
| {return __x.__p_ == __y.__p_;} |
| friend _LIBCPP_INLINE_VISIBILITY |
| bool operator!=(const piecewise_constant_distribution& __x, |
| const piecewise_constant_distribution& __y) |
| {return !(__x == __y);} |
| |
| template <class _CharT, class _Traits, class _RT> |
| friend |
| basic_ostream<_CharT, _Traits>& |
| operator<<(basic_ostream<_CharT, _Traits>& __os, |
| const piecewise_constant_distribution<_RT>& __x); |
| |
| template <class _CharT, class _Traits, class _RT> |
| friend |
| basic_istream<_CharT, _Traits>& |
| operator>>(basic_istream<_CharT, _Traits>& __is, |
| piecewise_constant_distribution<_RT>& __x); |
| }; |
| |
| template<class _RealType> |
| typename piecewise_constant_distribution<_RealType>::param_type & |
| piecewise_constant_distribution<_RealType>::param_type::operator= |
| (const param_type& __rhs) |
| { |
| // These can throw |
| __b_.reserve (__rhs.__b_.size ()); |
| __densities_.reserve(__rhs.__densities_.size()); |
| __areas_.reserve (__rhs.__areas_.size()); |
| |
| // These can not throw |
| __b_ = __rhs.__b_; |
| __densities_ = __rhs.__densities_; |
| __areas_ = __rhs.__areas_; |
| return *this; |
| } |
| |
| template<class _RealType> |
| void |
| piecewise_constant_distribution<_RealType>::param_type::__init() |
| { |
| // __densities_ contains non-normalized areas |
| result_type __total_area = _VSTD::accumulate(__densities_.begin(), |
| __densities_.end(), |
| result_type()); |
| for (size_t __i = 0; __i < __densities_.size(); ++__i) |
| __densities_[__i] /= __total_area; |
| // __densities_ contains normalized areas |
| __areas_.assign(__densities_.size(), result_type()); |
| _VSTD::partial_sum(__densities_.begin(), __densities_.end() - 1, |
| __areas_.begin() + 1); |
| // __areas_ contains partial sums of normalized areas: [0, __densities_ - 1] |
| __densities_.back() = 1 - __areas_.back(); // correct round off error |
| for (size_t __i = 0; __i < __densities_.size(); ++__i) |
| __densities_[__i] /= (__b_[__i+1] - __b_[__i]); |
| // __densities_ now contains __densities_ |
| } |
| |
| template<class _RealType> |
| piecewise_constant_distribution<_RealType>::param_type::param_type() |
| : __b_(2), |
| __densities_(1, 1.0), |
| __areas_(1, 0.0) |
| { |
| __b_[1] = 1; |
| } |
| |
| template<class _RealType> |
| template<class _InputIteratorB, class _InputIteratorW> |
| piecewise_constant_distribution<_RealType>::param_type::param_type( |
| _InputIteratorB __fB, _InputIteratorB __lB, _InputIteratorW __fW) |
| : __b_(__fB, __lB) |
| { |
| if (__b_.size() < 2) |
| { |
| __b_.resize(2); |
| __b_[0] = 0; |
| __b_[1] = 1; |
| __densities_.assign(1, 1.0); |
| __areas_.assign(1, 0.0); |
| } |
| else |
| { |
| __densities_.reserve(__b_.size() - 1); |
| for (size_t __i = 0; __i < __b_.size() - 1; ++__i, ++__fW) |
| __densities_.push_back(*__fW); |
| __init(); |
| } |
| } |
| |
| #ifndef _LIBCPP_CXX03_LANG |
| |
| template<class _RealType> |
| template<class _UnaryOperation> |
| piecewise_constant_distribution<_RealType>::param_type::param_type( |
| initializer_list<result_type> __bl, _UnaryOperation __fw) |
| : __b_(__bl.begin(), __bl.end()) |
| { |
| if (__b_.size() < 2) |
| { |
| __b_.resize(2); |
| __b_[0] = 0; |
| __b_[1] = 1; |
| __densities_.assign(1, 1.0); |
| __areas_.assign(1, 0.0); |
| } |
| else |
| { |
| __densities_.reserve(__b_.size() - 1); |
| for (size_t __i = 0; __i < __b_.size() - 1; ++__i) |
| __densities_.push_back(__fw((__b_[__i+1] + __b_[__i])*.5)); |
| __init(); |
| } |
| } |
| |
| #endif // _LIBCPP_CXX03_LANG |
| |
| template<class _RealType> |
| template<class _UnaryOperation> |
| piecewise_constant_distribution<_RealType>::param_type::param_type( |
| size_t __nw, result_type __xmin, result_type __xmax, _UnaryOperation __fw) |
| : __b_(__nw == 0 ? 2 : __nw + 1) |
| { |
| size_t __n = __b_.size() - 1; |
| result_type __d = (__xmax - __xmin) / __n; |
| __densities_.reserve(__n); |
| for (size_t __i = 0; __i < __n; ++__i) |
| { |
| __b_[__i] = __xmin + __i * __d; |
| __densities_.push_back(__fw(__b_[__i] + __d*.5)); |
| } |
| __b_[__n] = __xmax; |
| __init(); |
| } |
| |
| template<class _RealType> |
| template<class _URNG> |
| _RealType |
| piecewise_constant_distribution<_RealType>::operator()(_URNG& __g, const param_type& __p) |
| { |
| typedef uniform_real_distribution<result_type> _Gen; |
| result_type __u = _Gen()(__g); |
| ptrdiff_t __k = _VSTD::upper_bound(__p.__areas_.begin(), __p.__areas_.end(), |
| __u) - __p.__areas_.begin() - 1; |
| return (__u - __p.__areas_[__k]) / __p.__densities_[__k] + __p.__b_[__k]; |
| } |
| |
| template <class _CharT, class _Traits, class _RT> |
| basic_ostream<_CharT, _Traits>& |
| operator<<(basic_ostream<_CharT, _Traits>& __os, |
| const piecewise_constant_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); |
| size_t __n = __x.__p_.__b_.size(); |
| __os << __n; |
| for (size_t __i = 0; __i < __n; ++__i) |
| __os << __sp << __x.__p_.__b_[__i]; |
| __n = __x.__p_.__densities_.size(); |
| __os << __sp << __n; |
| for (size_t __i = 0; __i < __n; ++__i) |
| __os << __sp << __x.__p_.__densities_[__i]; |
| __n = __x.__p_.__areas_.size(); |
| __os << __sp << __n; |
| for (size_t __i = 0; __i < __n; ++__i) |
| __os << __sp << __x.__p_.__areas_[__i]; |
| return __os; |
| } |
| |
| template <class _CharT, class _Traits, class _RT> |
| basic_istream<_CharT, _Traits>& |
| operator>>(basic_istream<_CharT, _Traits>& __is, |
| piecewise_constant_distribution<_RT>& __x) |
| { |
| typedef piecewise_constant_distribution<_RT> _Eng; |
| typedef typename _Eng::result_type result_type; |
| __save_flags<_CharT, _Traits> __lx(__is); |
| typedef basic_istream<_CharT, _Traits> _Istream; |
| __is.flags(_Istream::dec | _Istream::skipws); |
| size_t __n; |
| __is >> __n; |
| vector<result_type> __b(__n); |
| for (size_t __i = 0; __i < __n; ++__i) |
| __is >> __b[__i]; |
| __is >> __n; |
| vector<result_type> __densities(__n); |
| for (size_t __i = 0; __i < __n; ++__i) |
| __is >> __densities[__i]; |
| __is >> __n; |
| vector<result_type> __areas(__n); |
| for (size_t __i = 0; __i < __n; ++__i) |
| __is >> __areas[__i]; |
| if (!__is.fail()) |
| { |
| swap(__x.__p_.__b_, __b); |
| swap(__x.__p_.__densities_, __densities); |
| swap(__x.__p_.__areas_, __areas); |
| } |
| return __is; |
| } |
| |
| _LIBCPP_END_NAMESPACE_STD |
| |
| _LIBCPP_POP_MACROS |
| |
| #endif // _LIBCPP___RANDOM_PIECEWISE_CONSTANT_DISTRIBUTION_H |
