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Diffstat (limited to 'third_party/abseil_cpp/absl/random/uniform_real_distribution.h')
| -rw-r--r-- | third_party/abseil_cpp/absl/random/uniform_real_distribution.h | 202 |
1 files changed, 0 insertions, 202 deletions
diff --git a/third_party/abseil_cpp/absl/random/uniform_real_distribution.h b/third_party/abseil_cpp/absl/random/uniform_real_distribution.h deleted file mode 100644 index 5ba17b2341..0000000000 --- a/third_party/abseil_cpp/absl/random/uniform_real_distribution.h +++ /dev/null @@ -1,202 +0,0 @@ -// Copyright 2017 The Abseil Authors. -// -// Licensed under the Apache License, Version 2.0 (the "License"); -// you may not use this file except in compliance with the License. -// You may obtain a copy of the License at -// -// https://www.apache.org/licenses/LICENSE-2.0 -// -// Unless required by applicable law or agreed to in writing, software -// distributed under the License is distributed on an "AS IS" BASIS, -// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. -// See the License for the specific language governing permissions and -// limitations under the License. -// -// ----------------------------------------------------------------------------- -// File: uniform_real_distribution.h -// ----------------------------------------------------------------------------- -// -// This header defines a class for representing a uniform floating-point -// distribution over a half-open interval [a,b). You use this distribution in -// combination with an Abseil random bit generator to produce random values -// according to the rules of the distribution. -// -// `absl::uniform_real_distribution` is a drop-in replacement for the C++11 -// `std::uniform_real_distribution` [rand.dist.uni.real] but is considerably -// faster than the libstdc++ implementation. -// -// Note: the standard-library version may occasionally return `1.0` when -// default-initialized. See https://bugs.llvm.org//show_bug.cgi?id=18767 -// `absl::uniform_real_distribution` does not exhibit this behavior. - -#ifndef ABSL_RANDOM_UNIFORM_REAL_DISTRIBUTION_H_ -#define ABSL_RANDOM_UNIFORM_REAL_DISTRIBUTION_H_ - -#include <cassert> -#include <cmath> -#include <cstdint> -#include <istream> -#include <limits> -#include <type_traits> - -#include "absl/meta/type_traits.h" -#include "absl/random/internal/fast_uniform_bits.h" -#include "absl/random/internal/generate_real.h" -#include "absl/random/internal/iostream_state_saver.h" - -namespace absl { -ABSL_NAMESPACE_BEGIN - -// absl::uniform_real_distribution<T> -// -// This distribution produces random floating-point values uniformly distributed -// over the half-open interval [a, b). -// -// Example: -// -// absl::BitGen gen; -// -// // Use the distribution to produce a value between 0.0 (inclusive) -// // and 1.0 (exclusive). -// double value = absl::uniform_real_distribution<double>(0, 1)(gen); -// -template <typename RealType = double> -class uniform_real_distribution { - public: - using result_type = RealType; - - class param_type { - public: - using distribution_type = uniform_real_distribution; - - explicit param_type(result_type lo = 0, result_type hi = 1) - : lo_(lo), hi_(hi), range_(hi - lo) { - // [rand.dist.uni.real] preconditions 2 & 3 - assert(lo <= hi); - // NOTE: For integral types, we can promote the range to an unsigned type, - // which gives full width of the range. However for real (fp) types, this - // is not possible, so value generation cannot use the full range of the - // real type. - assert(range_ <= (std::numeric_limits<result_type>::max)()); - assert(std::isfinite(range_)); - } - - result_type a() const { return lo_; } - result_type b() const { return hi_; } - - friend bool operator==(const param_type& a, const param_type& b) { - return a.lo_ == b.lo_ && a.hi_ == b.hi_; - } - - friend bool operator!=(const param_type& a, const param_type& b) { - return !(a == b); - } - - private: - friend class uniform_real_distribution; - result_type lo_, hi_, range_; - - static_assert(std::is_floating_point<RealType>::value, - "Class-template absl::uniform_real_distribution<> must be " - "parameterized using a floating-point type."); - }; - - uniform_real_distribution() : uniform_real_distribution(0) {} - - explicit uniform_real_distribution(result_type lo, result_type hi = 1) - : param_(lo, hi) {} - - explicit uniform_real_distribution(const param_type& param) : param_(param) {} - - // uniform_real_distribution<T>::reset() - // - // Resets the uniform real distribution. Note that this function has no effect - // because the distribution already produces independent values. - void reset() {} - - template <typename URBG> - result_type operator()(URBG& gen) { // NOLINT(runtime/references) - return operator()(gen, param_); - } - - template <typename URBG> - result_type operator()(URBG& gen, // NOLINT(runtime/references) - const param_type& p); - - result_type a() const { return param_.a(); } - result_type b() const { return param_.b(); } - - param_type param() const { return param_; } - void param(const param_type& params) { param_ = params; } - - result_type(min)() const { return a(); } - result_type(max)() const { return b(); } - - friend bool operator==(const uniform_real_distribution& a, - const uniform_real_distribution& b) { - return a.param_ == b.param_; - } - friend bool operator!=(const uniform_real_distribution& a, - const uniform_real_distribution& b) { - return a.param_ != b.param_; - } - - private: - param_type param_; - random_internal::FastUniformBits<uint64_t> fast_u64_; -}; - -// ----------------------------------------------------------------------------- -// Implementation details follow -// ----------------------------------------------------------------------------- -template <typename RealType> -template <typename URBG> -typename uniform_real_distribution<RealType>::result_type -uniform_real_distribution<RealType>::operator()( - URBG& gen, const param_type& p) { // NOLINT(runtime/references) - using random_internal::GeneratePositiveTag; - using random_internal::GenerateRealFromBits; - using real_type = - absl::conditional_t<std::is_same<RealType, float>::value, float, double>; - - while (true) { - const result_type sample = - GenerateRealFromBits<real_type, GeneratePositiveTag, true>( - fast_u64_(gen)); - const result_type res = p.a() + (sample * p.range_); - if (res < p.b() || p.range_ <= 0 || !std::isfinite(p.range_)) { - return res; - } - // else sample rejected, try again. - } -} - -template <typename CharT, typename Traits, typename RealType> -std::basic_ostream<CharT, Traits>& operator<<( - std::basic_ostream<CharT, Traits>& os, // NOLINT(runtime/references) - const uniform_real_distribution<RealType>& x) { - auto saver = random_internal::make_ostream_state_saver(os); - os.precision(random_internal::stream_precision_helper<RealType>::kPrecision); - os << x.a() << os.fill() << x.b(); - return os; -} - -template <typename CharT, typename Traits, typename RealType> -std::basic_istream<CharT, Traits>& operator>>( - std::basic_istream<CharT, Traits>& is, // NOLINT(runtime/references) - uniform_real_distribution<RealType>& x) { // NOLINT(runtime/references) - using param_type = typename uniform_real_distribution<RealType>::param_type; - using result_type = typename uniform_real_distribution<RealType>::result_type; - auto saver = random_internal::make_istream_state_saver(is); - auto a = random_internal::read_floating_point<result_type>(is); - if (is.fail()) return is; - auto b = random_internal::read_floating_point<result_type>(is); - if (!is.fail()) { - x.param(param_type(a, b)); - } - return is; -} -ABSL_NAMESPACE_END -} // namespace absl - -#endif // ABSL_RANDOM_UNIFORM_REAL_DISTRIBUTION_H_ |