Abseil Common Libraries (C++) (grcp 依赖) https://abseil.io/
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Export of internal Abseil changes -- f012012ef78234a6a4585321b67d7b7c92ebc266 by Laramie Leavitt <lar@google.com>: Slight restructuring of absl/random/internal randen implementation. Convert round-keys.inc into randen_round_keys.cc file. Consistently use a 128-bit pointer type for internal method parameters. This allows simpler pointer arithmetic in C++ & permits removal of some constants and casts. Remove some redundancy in comments & constexpr variables. Specifically, all references to Randen algorithm parameters use RandenTraits; duplication in RandenSlow removed. PiperOrigin-RevId: 312190313 -- dc8b42e054046741e9ed65335bfdface997c6063 by Abseil Team <absl-team@google.com>: Internal change. PiperOrigin-RevId: 312167304 -- f13d248fafaf206492c1362c3574031aea3abaf7 by Matthew Brown <matthewbr@google.com>: Cleanup StrFormat extensions a little. PiperOrigin-RevId: 312166336 -- 9d9117589667afe2332bb7ad42bc967ca7c54502 by Derek Mauro <dmauro@google.com>: Internal change PiperOrigin-RevId: 312105213 -- 9a12b9b3aa0e59b8ee6cf9408ed0029045543a9b by Abseil Team <absl-team@google.com>: Complete IGNORE_TYPE macro renaming. PiperOrigin-RevId: 311999699 -- 64756f20d61021d999bd0d4c15e9ad3857382f57 by Gennadiy Rozental <rogeeff@google.com>: Switch to fixed bytes specific default value. This fixes the Abseil Flags for big endian platforms. PiperOrigin-RevId: 311844448 -- bdbe6b5b29791dbc3816ada1828458b3010ff1e9 by Laramie Leavitt <lar@google.com>: Change many distribution tests to use pcg_engine as a deterministic source of entropy. It's reasonable to test that the BitGen itself has good entropy, however when testing the cross product of all random distributions x all the architecture variations x all submitted changes results in a large number of tests. In order to account for these failures while still using good entropy requires that our allowed sigma need to account for all of these independent tests. Our current sigma values are too restrictive, and we see a lot of failures, so we have to either relax the sigma values or convert some of the statistical tests to use deterministic values. This changelist does the latter. PiperOrigin-RevId: 311840096 GitOrigin-RevId: f012012ef78234a6a4585321b67d7b7c92ebc266 Change-Id: Ic84886f38ff30d7d72c126e9b63c9a61eb729a1a
5 years ago
// 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: distributions.h
// -----------------------------------------------------------------------------
//
// This header defines functions representing distributions, which you use in
// combination with an Abseil random bit generator to produce random values
// according to the rules of that distribution.
//
// The Abseil random library defines the following distributions within this
// file:
//
// * `absl::Uniform` for uniform (constant) distributions having constant
// probability
// * `absl::Bernoulli` for discrete distributions having exactly two outcomes
// * `absl::Beta` for continuous distributions parameterized through two
// free parameters
// * `absl::Exponential` for discrete distributions of events occurring
// continuously and independently at a constant average rate
// * `absl::Gaussian` (also known as "normal distributions") for continuous
// distributions using an associated quadratic function
// * `absl::LogUniform` for continuous uniform distributions where the log
// to the given base of all values is uniform
// * `absl::Poisson` for discrete probability distributions that express the
// probability of a given number of events occurring within a fixed interval
// * `absl::Zipf` for discrete probability distributions commonly used for
// modelling of rare events
//
// Prefer use of these distribution function classes over manual construction of
// your own distribution classes, as it allows library maintainers greater
// flexibility to change the underlying implementation in the future.
#ifndef ABSL_RANDOM_DISTRIBUTIONS_H_
#define ABSL_RANDOM_DISTRIBUTIONS_H_
#include <algorithm>
#include <cmath>
#include <limits>
#include <random>
#include <type_traits>
#include "absl/base/internal/inline_variable.h"
#include "absl/random/bernoulli_distribution.h"
#include "absl/random/beta_distribution.h"
#include "absl/random/exponential_distribution.h"
#include "absl/random/gaussian_distribution.h"
Export of internal Abseil changes -- 7d0468a6610ed85586d5c87fd65de8dac5118923 by Derek Mauro <dmauro@google.com>: Import of CCTZ from GitHub. PiperOrigin-RevId: 313226473 -- 1131ef6d116f5ce7d46537a82f300ea06dcaaa53 by Gennadiy Rozental <rogeeff@google.com>: Migrate internal interface to use mutable references. PiperOrigin-RevId: 312931131 -- 96225212a9f5fbd0b38c71fe65539164992c7c3b by Laramie Leavitt <lar@google.com>: Remove random/internal/distributions.h This file was something of an historical artifact. All of the related code has either been removed or migraged, and so the only remaining type belongs with uniform_helper.h, as it is used to infer the return type of the absl::Uniform method in a few cases. PiperOrigin-RevId: 312878173 -- 6dcbd5be58ad425e08740ff64088373ee7fe4a72 by Mark Barolak <mbar@google.com>: Release the StrFormat test case for Cords to open source. PiperOrigin-RevId: 312707974 -- 34484d18dfb63a0a7ad6e2aaeb570e33592968be by Abseil Team <absl-team@google.com>: Let Cord::Cord(string&&), Cord::operator=(string&&), Cord::Append(string&&), and Cord::Prepend(string&&) steal string data and embed it into the Cord as a single external chunk, instead of copying it into flat chunks (at most 4083-byte each). Stealing string data is faster, but it creates a long chunk, which leads to a higher more memory usage if its subcords are created and outlive the whole Cord. These functions revert to copying the data if any of the following conditions holds: - string size is at most kMaxBytesToCopy (511), to avoid the overhead of an external chunk for short strings; - less than half of string capacity is used, to avoid pinning to much unused memory. PiperOrigin-RevId: 312683785 GitOrigin-RevId: 7d0468a6610ed85586d5c87fd65de8dac5118923 Change-Id: If79b5a1dfe6d53a8ddddbc7da84338f11fc4cfa3
5 years ago
#include "absl/random/internal/distribution_caller.h" // IWYU pragma: export
Export of internal Abseil changes -- f012012ef78234a6a4585321b67d7b7c92ebc266 by Laramie Leavitt <lar@google.com>: Slight restructuring of absl/random/internal randen implementation. Convert round-keys.inc into randen_round_keys.cc file. Consistently use a 128-bit pointer type for internal method parameters. This allows simpler pointer arithmetic in C++ & permits removal of some constants and casts. Remove some redundancy in comments & constexpr variables. Specifically, all references to Randen algorithm parameters use RandenTraits; duplication in RandenSlow removed. PiperOrigin-RevId: 312190313 -- dc8b42e054046741e9ed65335bfdface997c6063 by Abseil Team <absl-team@google.com>: Internal change. PiperOrigin-RevId: 312167304 -- f13d248fafaf206492c1362c3574031aea3abaf7 by Matthew Brown <matthewbr@google.com>: Cleanup StrFormat extensions a little. PiperOrigin-RevId: 312166336 -- 9d9117589667afe2332bb7ad42bc967ca7c54502 by Derek Mauro <dmauro@google.com>: Internal change PiperOrigin-RevId: 312105213 -- 9a12b9b3aa0e59b8ee6cf9408ed0029045543a9b by Abseil Team <absl-team@google.com>: Complete IGNORE_TYPE macro renaming. PiperOrigin-RevId: 311999699 -- 64756f20d61021d999bd0d4c15e9ad3857382f57 by Gennadiy Rozental <rogeeff@google.com>: Switch to fixed bytes specific default value. This fixes the Abseil Flags for big endian platforms. PiperOrigin-RevId: 311844448 -- bdbe6b5b29791dbc3816ada1828458b3010ff1e9 by Laramie Leavitt <lar@google.com>: Change many distribution tests to use pcg_engine as a deterministic source of entropy. It's reasonable to test that the BitGen itself has good entropy, however when testing the cross product of all random distributions x all the architecture variations x all submitted changes results in a large number of tests. In order to account for these failures while still using good entropy requires that our allowed sigma need to account for all of these independent tests. Our current sigma values are too restrictive, and we see a lot of failures, so we have to either relax the sigma values or convert some of the statistical tests to use deterministic values. This changelist does the latter. PiperOrigin-RevId: 311840096 GitOrigin-RevId: f012012ef78234a6a4585321b67d7b7c92ebc266 Change-Id: Ic84886f38ff30d7d72c126e9b63c9a61eb729a1a
5 years ago
#include "absl/random/internal/uniform_helper.h" // IWYU pragma: export
#include "absl/random/log_uniform_int_distribution.h"
#include "absl/random/poisson_distribution.h"
#include "absl/random/uniform_int_distribution.h"
#include "absl/random/uniform_real_distribution.h"
#include "absl/random/zipf_distribution.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
ABSL_INTERNAL_INLINE_CONSTEXPR(IntervalClosedClosedTag, IntervalClosedClosed,
{});
ABSL_INTERNAL_INLINE_CONSTEXPR(IntervalClosedClosedTag, IntervalClosed, {});
ABSL_INTERNAL_INLINE_CONSTEXPR(IntervalClosedOpenTag, IntervalClosedOpen, {});
ABSL_INTERNAL_INLINE_CONSTEXPR(IntervalOpenOpenTag, IntervalOpenOpen, {});
ABSL_INTERNAL_INLINE_CONSTEXPR(IntervalOpenOpenTag, IntervalOpen, {});
ABSL_INTERNAL_INLINE_CONSTEXPR(IntervalOpenClosedTag, IntervalOpenClosed, {});
// -----------------------------------------------------------------------------
// absl::Uniform<T>(tag, bitgen, lo, hi)
// -----------------------------------------------------------------------------
//
// `absl::Uniform()` produces random values of type `T` uniformly distributed in
// a defined interval {lo, hi}. The interval `tag` defines the type of interval
// which should be one of the following possible values:
//
// * `absl::IntervalOpenOpen`
// * `absl::IntervalOpenClosed`
// * `absl::IntervalClosedOpen`
// * `absl::IntervalClosedClosed`
//
// where "open" refers to an exclusive value (excluded) from the output, while
// "closed" refers to an inclusive value (included) from the output.
//
// In the absence of an explicit return type `T`, `absl::Uniform()` will deduce
// the return type based on the provided endpoint arguments {A lo, B hi}.
// Given these endpoints, one of {A, B} will be chosen as the return type, if
// a type can be implicitly converted into the other in a lossless way. The
// lack of any such implicit conversion between {A, B} will produce a
// compile-time error
//
// See https://en.wikipedia.org/wiki/Uniform_distribution_(continuous)
//
// Example:
//
// absl::BitGen bitgen;
//
// // Produce a random float value between 0.0 and 1.0, inclusive
// auto x = absl::Uniform(absl::IntervalClosedClosed, bitgen, 0.0f, 1.0f);
//
// // The most common interval of `absl::IntervalClosedOpen` is available by
// // default:
//
// auto x = absl::Uniform(bitgen, 0.0f, 1.0f);
//
// // Return-types are typically inferred from the arguments, however callers
// // can optionally provide an explicit return-type to the template.
//
// auto x = absl::Uniform<float>(bitgen, 0, 1);
//
template <typename R = void, typename TagType, typename URBG>
typename absl::enable_if_t<!std::is_same<R, void>::value, R> //
Uniform(TagType tag,
URBG&& urbg, // NOLINT(runtime/references)
R lo, R hi) {
using gen_t = absl::decay_t<URBG>;
using distribution_t = random_internal::UniformDistributionWrapper<R>;
auto a = random_internal::uniform_lower_bound(tag, lo, hi);
auto b = random_internal::uniform_upper_bound(tag, lo, hi);
Export of internal Abseil changes -- 790f9061df340cd900e8da70e66c363f7af3c2eb by Abseil Team <absl-team@google.com>: Add support for rvalue reference to function types. PiperOrigin-RevId: 324508531 -- 51fe201dbb41a3ebc3d49ff65250b5f464279d43 by Abseil Team <absl-team@google.com>: Cleaning up function comment style; no substantive change. PiperOrigin-RevId: 324497401 -- da8595d5266577d0c170528d12f6de17b8affcc2 by Abseil Team <absl-team@google.com>: Add support for demangling GNU vector types. PiperOrigin-RevId: 324494559 -- 0cb0acf88c1750f6963c9cb85249f9b4f0bd5104 by Abseil Team <absl-team@google.com>: Add support for thread-local types. PiperOrigin-RevId: 324491183 -- c676bc8380560599cd26f7f231e04e6be532e904 by Abseil Team <absl-team@google.com>: Add support for demangling "Du" (char8_t). PiperOrigin-RevId: 324441607 -- b218bf6467bc62b327214782c881e8224ad91509 by Abseil Team <absl-team@google.com>: Update doc comments in header of `any.h` to reflect that `absl::variant` has been released. PiperOrigin-RevId: 324431690 -- e5b579f3f1aa598c1f62e71dba7103b98811de59 by Laramie Leavitt <lar@google.com>: Bugfix: Fix bounds in absl::Uniform where one of the bounds is min/max. When absl::Uniform(rng, tag, a, b) is called, the tag is used in conjunction with the type to determine whether or not to manipulate the bounds to make them inclusive or exclusive through the uniform_*_bound functions. Unfortunately, at limits of the interval the function was not well behaved. The previous implementation used wrapping arithmetic. This causes incorrect bounds computation at the extremes (numeric_limits::min / numeric_limits::max) the bound would wrap. Improve this situation by: 1/ Changing the uniform_*_bound functions to use saturating arithmetic instead of wrapping, thus in the unsigned case, the upper_bound of IntervalOpenOpen for 0 is now 0, rather than numeric_limits::max, likewise for the lower bound. 2/ Adjusting the hi/lo checks in the distributions. When the interval is empty, such as for absl::Uniform(absl::IntervalOpenOpen, gen, 1, 0), the return value is somewhat nonsensical. Now absl::Uniform more consistently returns the low input rather than any adjusted input. In the above case, that means that 1 is returned rather than 2. NOTE: Calls to absl::Uniform where the resolved upper bound is < the lower bound are still ill-formed and should be avoided. 3/ Adding better tests. The underlying uniform_*_distribution classes are not affected. PiperOrigin-RevId: 324240873 GitOrigin-RevId: 790f9061df340cd900e8da70e66c363f7af3c2eb Change-Id: I2a2208650ea3135c575e200b868ce1d275069fc8
4 years ago
if (!random_internal::is_uniform_range_valid(a, b)) return lo;
Export of internal Abseil changes -- f012012ef78234a6a4585321b67d7b7c92ebc266 by Laramie Leavitt <lar@google.com>: Slight restructuring of absl/random/internal randen implementation. Convert round-keys.inc into randen_round_keys.cc file. Consistently use a 128-bit pointer type for internal method parameters. This allows simpler pointer arithmetic in C++ & permits removal of some constants and casts. Remove some redundancy in comments & constexpr variables. Specifically, all references to Randen algorithm parameters use RandenTraits; duplication in RandenSlow removed. PiperOrigin-RevId: 312190313 -- dc8b42e054046741e9ed65335bfdface997c6063 by Abseil Team <absl-team@google.com>: Internal change. PiperOrigin-RevId: 312167304 -- f13d248fafaf206492c1362c3574031aea3abaf7 by Matthew Brown <matthewbr@google.com>: Cleanup StrFormat extensions a little. PiperOrigin-RevId: 312166336 -- 9d9117589667afe2332bb7ad42bc967ca7c54502 by Derek Mauro <dmauro@google.com>: Internal change PiperOrigin-RevId: 312105213 -- 9a12b9b3aa0e59b8ee6cf9408ed0029045543a9b by Abseil Team <absl-team@google.com>: Complete IGNORE_TYPE macro renaming. PiperOrigin-RevId: 311999699 -- 64756f20d61021d999bd0d4c15e9ad3857382f57 by Gennadiy Rozental <rogeeff@google.com>: Switch to fixed bytes specific default value. This fixes the Abseil Flags for big endian platforms. PiperOrigin-RevId: 311844448 -- bdbe6b5b29791dbc3816ada1828458b3010ff1e9 by Laramie Leavitt <lar@google.com>: Change many distribution tests to use pcg_engine as a deterministic source of entropy. It's reasonable to test that the BitGen itself has good entropy, however when testing the cross product of all random distributions x all the architecture variations x all submitted changes results in a large number of tests. In order to account for these failures while still using good entropy requires that our allowed sigma need to account for all of these independent tests. Our current sigma values are too restrictive, and we see a lot of failures, so we have to either relax the sigma values or convert some of the statistical tests to use deterministic values. This changelist does the latter. PiperOrigin-RevId: 311840096 GitOrigin-RevId: f012012ef78234a6a4585321b67d7b7c92ebc266 Change-Id: Ic84886f38ff30d7d72c126e9b63c9a61eb729a1a
5 years ago
return random_internal::DistributionCaller<gen_t>::template Call<
distribution_t>(&urbg, tag, lo, hi);
}
// absl::Uniform<T>(bitgen, lo, hi)
//
// Overload of `Uniform()` using the default closed-open interval of [lo, hi),
// and returning values of type `T`
template <typename R = void, typename URBG>
typename absl::enable_if_t<!std::is_same<R, void>::value, R> //
Uniform(URBG&& urbg, // NOLINT(runtime/references)
R lo, R hi) {
using gen_t = absl::decay_t<URBG>;
using distribution_t = random_internal::UniformDistributionWrapper<R>;
constexpr auto tag = absl::IntervalClosedOpen;
Export of internal Abseil changes -- 790f9061df340cd900e8da70e66c363f7af3c2eb by Abseil Team <absl-team@google.com>: Add support for rvalue reference to function types. PiperOrigin-RevId: 324508531 -- 51fe201dbb41a3ebc3d49ff65250b5f464279d43 by Abseil Team <absl-team@google.com>: Cleaning up function comment style; no substantive change. PiperOrigin-RevId: 324497401 -- da8595d5266577d0c170528d12f6de17b8affcc2 by Abseil Team <absl-team@google.com>: Add support for demangling GNU vector types. PiperOrigin-RevId: 324494559 -- 0cb0acf88c1750f6963c9cb85249f9b4f0bd5104 by Abseil Team <absl-team@google.com>: Add support for thread-local types. PiperOrigin-RevId: 324491183 -- c676bc8380560599cd26f7f231e04e6be532e904 by Abseil Team <absl-team@google.com>: Add support for demangling "Du" (char8_t). PiperOrigin-RevId: 324441607 -- b218bf6467bc62b327214782c881e8224ad91509 by Abseil Team <absl-team@google.com>: Update doc comments in header of `any.h` to reflect that `absl::variant` has been released. PiperOrigin-RevId: 324431690 -- e5b579f3f1aa598c1f62e71dba7103b98811de59 by Laramie Leavitt <lar@google.com>: Bugfix: Fix bounds in absl::Uniform where one of the bounds is min/max. When absl::Uniform(rng, tag, a, b) is called, the tag is used in conjunction with the type to determine whether or not to manipulate the bounds to make them inclusive or exclusive through the uniform_*_bound functions. Unfortunately, at limits of the interval the function was not well behaved. The previous implementation used wrapping arithmetic. This causes incorrect bounds computation at the extremes (numeric_limits::min / numeric_limits::max) the bound would wrap. Improve this situation by: 1/ Changing the uniform_*_bound functions to use saturating arithmetic instead of wrapping, thus in the unsigned case, the upper_bound of IntervalOpenOpen for 0 is now 0, rather than numeric_limits::max, likewise for the lower bound. 2/ Adjusting the hi/lo checks in the distributions. When the interval is empty, such as for absl::Uniform(absl::IntervalOpenOpen, gen, 1, 0), the return value is somewhat nonsensical. Now absl::Uniform more consistently returns the low input rather than any adjusted input. In the above case, that means that 1 is returned rather than 2. NOTE: Calls to absl::Uniform where the resolved upper bound is < the lower bound are still ill-formed and should be avoided. 3/ Adding better tests. The underlying uniform_*_distribution classes are not affected. PiperOrigin-RevId: 324240873 GitOrigin-RevId: 790f9061df340cd900e8da70e66c363f7af3c2eb Change-Id: I2a2208650ea3135c575e200b868ce1d275069fc8
4 years ago
Export of internal Abseil changes -- f012012ef78234a6a4585321b67d7b7c92ebc266 by Laramie Leavitt <lar@google.com>: Slight restructuring of absl/random/internal randen implementation. Convert round-keys.inc into randen_round_keys.cc file. Consistently use a 128-bit pointer type for internal method parameters. This allows simpler pointer arithmetic in C++ & permits removal of some constants and casts. Remove some redundancy in comments & constexpr variables. Specifically, all references to Randen algorithm parameters use RandenTraits; duplication in RandenSlow removed. PiperOrigin-RevId: 312190313 -- dc8b42e054046741e9ed65335bfdface997c6063 by Abseil Team <absl-team@google.com>: Internal change. PiperOrigin-RevId: 312167304 -- f13d248fafaf206492c1362c3574031aea3abaf7 by Matthew Brown <matthewbr@google.com>: Cleanup StrFormat extensions a little. PiperOrigin-RevId: 312166336 -- 9d9117589667afe2332bb7ad42bc967ca7c54502 by Derek Mauro <dmauro@google.com>: Internal change PiperOrigin-RevId: 312105213 -- 9a12b9b3aa0e59b8ee6cf9408ed0029045543a9b by Abseil Team <absl-team@google.com>: Complete IGNORE_TYPE macro renaming. PiperOrigin-RevId: 311999699 -- 64756f20d61021d999bd0d4c15e9ad3857382f57 by Gennadiy Rozental <rogeeff@google.com>: Switch to fixed bytes specific default value. This fixes the Abseil Flags for big endian platforms. PiperOrigin-RevId: 311844448 -- bdbe6b5b29791dbc3816ada1828458b3010ff1e9 by Laramie Leavitt <lar@google.com>: Change many distribution tests to use pcg_engine as a deterministic source of entropy. It's reasonable to test that the BitGen itself has good entropy, however when testing the cross product of all random distributions x all the architecture variations x all submitted changes results in a large number of tests. In order to account for these failures while still using good entropy requires that our allowed sigma need to account for all of these independent tests. Our current sigma values are too restrictive, and we see a lot of failures, so we have to either relax the sigma values or convert some of the statistical tests to use deterministic values. This changelist does the latter. PiperOrigin-RevId: 311840096 GitOrigin-RevId: f012012ef78234a6a4585321b67d7b7c92ebc266 Change-Id: Ic84886f38ff30d7d72c126e9b63c9a61eb729a1a
5 years ago
auto a = random_internal::uniform_lower_bound(tag, lo, hi);
auto b = random_internal::uniform_upper_bound(tag, lo, hi);
Export of internal Abseil changes -- 790f9061df340cd900e8da70e66c363f7af3c2eb by Abseil Team <absl-team@google.com>: Add support for rvalue reference to function types. PiperOrigin-RevId: 324508531 -- 51fe201dbb41a3ebc3d49ff65250b5f464279d43 by Abseil Team <absl-team@google.com>: Cleaning up function comment style; no substantive change. PiperOrigin-RevId: 324497401 -- da8595d5266577d0c170528d12f6de17b8affcc2 by Abseil Team <absl-team@google.com>: Add support for demangling GNU vector types. PiperOrigin-RevId: 324494559 -- 0cb0acf88c1750f6963c9cb85249f9b4f0bd5104 by Abseil Team <absl-team@google.com>: Add support for thread-local types. PiperOrigin-RevId: 324491183 -- c676bc8380560599cd26f7f231e04e6be532e904 by Abseil Team <absl-team@google.com>: Add support for demangling "Du" (char8_t). PiperOrigin-RevId: 324441607 -- b218bf6467bc62b327214782c881e8224ad91509 by Abseil Team <absl-team@google.com>: Update doc comments in header of `any.h` to reflect that `absl::variant` has been released. PiperOrigin-RevId: 324431690 -- e5b579f3f1aa598c1f62e71dba7103b98811de59 by Laramie Leavitt <lar@google.com>: Bugfix: Fix bounds in absl::Uniform where one of the bounds is min/max. When absl::Uniform(rng, tag, a, b) is called, the tag is used in conjunction with the type to determine whether or not to manipulate the bounds to make them inclusive or exclusive through the uniform_*_bound functions. Unfortunately, at limits of the interval the function was not well behaved. The previous implementation used wrapping arithmetic. This causes incorrect bounds computation at the extremes (numeric_limits::min / numeric_limits::max) the bound would wrap. Improve this situation by: 1/ Changing the uniform_*_bound functions to use saturating arithmetic instead of wrapping, thus in the unsigned case, the upper_bound of IntervalOpenOpen for 0 is now 0, rather than numeric_limits::max, likewise for the lower bound. 2/ Adjusting the hi/lo checks in the distributions. When the interval is empty, such as for absl::Uniform(absl::IntervalOpenOpen, gen, 1, 0), the return value is somewhat nonsensical. Now absl::Uniform more consistently returns the low input rather than any adjusted input. In the above case, that means that 1 is returned rather than 2. NOTE: Calls to absl::Uniform where the resolved upper bound is < the lower bound are still ill-formed and should be avoided. 3/ Adding better tests. The underlying uniform_*_distribution classes are not affected. PiperOrigin-RevId: 324240873 GitOrigin-RevId: 790f9061df340cd900e8da70e66c363f7af3c2eb Change-Id: I2a2208650ea3135c575e200b868ce1d275069fc8
4 years ago
if (!random_internal::is_uniform_range_valid(a, b)) return lo;
Export of internal Abseil changes -- f012012ef78234a6a4585321b67d7b7c92ebc266 by Laramie Leavitt <lar@google.com>: Slight restructuring of absl/random/internal randen implementation. Convert round-keys.inc into randen_round_keys.cc file. Consistently use a 128-bit pointer type for internal method parameters. This allows simpler pointer arithmetic in C++ & permits removal of some constants and casts. Remove some redundancy in comments & constexpr variables. Specifically, all references to Randen algorithm parameters use RandenTraits; duplication in RandenSlow removed. PiperOrigin-RevId: 312190313 -- dc8b42e054046741e9ed65335bfdface997c6063 by Abseil Team <absl-team@google.com>: Internal change. PiperOrigin-RevId: 312167304 -- f13d248fafaf206492c1362c3574031aea3abaf7 by Matthew Brown <matthewbr@google.com>: Cleanup StrFormat extensions a little. PiperOrigin-RevId: 312166336 -- 9d9117589667afe2332bb7ad42bc967ca7c54502 by Derek Mauro <dmauro@google.com>: Internal change PiperOrigin-RevId: 312105213 -- 9a12b9b3aa0e59b8ee6cf9408ed0029045543a9b by Abseil Team <absl-team@google.com>: Complete IGNORE_TYPE macro renaming. PiperOrigin-RevId: 311999699 -- 64756f20d61021d999bd0d4c15e9ad3857382f57 by Gennadiy Rozental <rogeeff@google.com>: Switch to fixed bytes specific default value. This fixes the Abseil Flags for big endian platforms. PiperOrigin-RevId: 311844448 -- bdbe6b5b29791dbc3816ada1828458b3010ff1e9 by Laramie Leavitt <lar@google.com>: Change many distribution tests to use pcg_engine as a deterministic source of entropy. It's reasonable to test that the BitGen itself has good entropy, however when testing the cross product of all random distributions x all the architecture variations x all submitted changes results in a large number of tests. In order to account for these failures while still using good entropy requires that our allowed sigma need to account for all of these independent tests. Our current sigma values are too restrictive, and we see a lot of failures, so we have to either relax the sigma values or convert some of the statistical tests to use deterministic values. This changelist does the latter. PiperOrigin-RevId: 311840096 GitOrigin-RevId: f012012ef78234a6a4585321b67d7b7c92ebc266 Change-Id: Ic84886f38ff30d7d72c126e9b63c9a61eb729a1a
5 years ago
return random_internal::DistributionCaller<gen_t>::template Call<
distribution_t>(&urbg, lo, hi);
}
// absl::Uniform(tag, bitgen, lo, hi)
//
// Overload of `Uniform()` using different (but compatible) lo, hi types. Note
// that a compile-error will result if the return type cannot be deduced
// correctly from the passed types.
template <typename R = void, typename TagType, typename URBG, typename A,
typename B>
typename absl::enable_if_t<std::is_same<R, void>::value,
random_internal::uniform_inferred_return_t<A, B>>
Uniform(TagType tag,
URBG&& urbg, // NOLINT(runtime/references)
A lo, B hi) {
using gen_t = absl::decay_t<URBG>;
using return_t = typename random_internal::uniform_inferred_return_t<A, B>;
using distribution_t = random_internal::UniformDistributionWrapper<return_t>;
auto a = random_internal::uniform_lower_bound<return_t>(tag, lo, hi);
auto b = random_internal::uniform_upper_bound<return_t>(tag, lo, hi);
Export of internal Abseil changes -- 790f9061df340cd900e8da70e66c363f7af3c2eb by Abseil Team <absl-team@google.com>: Add support for rvalue reference to function types. PiperOrigin-RevId: 324508531 -- 51fe201dbb41a3ebc3d49ff65250b5f464279d43 by Abseil Team <absl-team@google.com>: Cleaning up function comment style; no substantive change. PiperOrigin-RevId: 324497401 -- da8595d5266577d0c170528d12f6de17b8affcc2 by Abseil Team <absl-team@google.com>: Add support for demangling GNU vector types. PiperOrigin-RevId: 324494559 -- 0cb0acf88c1750f6963c9cb85249f9b4f0bd5104 by Abseil Team <absl-team@google.com>: Add support for thread-local types. PiperOrigin-RevId: 324491183 -- c676bc8380560599cd26f7f231e04e6be532e904 by Abseil Team <absl-team@google.com>: Add support for demangling "Du" (char8_t). PiperOrigin-RevId: 324441607 -- b218bf6467bc62b327214782c881e8224ad91509 by Abseil Team <absl-team@google.com>: Update doc comments in header of `any.h` to reflect that `absl::variant` has been released. PiperOrigin-RevId: 324431690 -- e5b579f3f1aa598c1f62e71dba7103b98811de59 by Laramie Leavitt <lar@google.com>: Bugfix: Fix bounds in absl::Uniform where one of the bounds is min/max. When absl::Uniform(rng, tag, a, b) is called, the tag is used in conjunction with the type to determine whether or not to manipulate the bounds to make them inclusive or exclusive through the uniform_*_bound functions. Unfortunately, at limits of the interval the function was not well behaved. The previous implementation used wrapping arithmetic. This causes incorrect bounds computation at the extremes (numeric_limits::min / numeric_limits::max) the bound would wrap. Improve this situation by: 1/ Changing the uniform_*_bound functions to use saturating arithmetic instead of wrapping, thus in the unsigned case, the upper_bound of IntervalOpenOpen for 0 is now 0, rather than numeric_limits::max, likewise for the lower bound. 2/ Adjusting the hi/lo checks in the distributions. When the interval is empty, such as for absl::Uniform(absl::IntervalOpenOpen, gen, 1, 0), the return value is somewhat nonsensical. Now absl::Uniform more consistently returns the low input rather than any adjusted input. In the above case, that means that 1 is returned rather than 2. NOTE: Calls to absl::Uniform where the resolved upper bound is < the lower bound are still ill-formed and should be avoided. 3/ Adding better tests. The underlying uniform_*_distribution classes are not affected. PiperOrigin-RevId: 324240873 GitOrigin-RevId: 790f9061df340cd900e8da70e66c363f7af3c2eb Change-Id: I2a2208650ea3135c575e200b868ce1d275069fc8
4 years ago
if (!random_internal::is_uniform_range_valid(a, b)) return lo;
Export of internal Abseil changes -- f012012ef78234a6a4585321b67d7b7c92ebc266 by Laramie Leavitt <lar@google.com>: Slight restructuring of absl/random/internal randen implementation. Convert round-keys.inc into randen_round_keys.cc file. Consistently use a 128-bit pointer type for internal method parameters. This allows simpler pointer arithmetic in C++ & permits removal of some constants and casts. Remove some redundancy in comments & constexpr variables. Specifically, all references to Randen algorithm parameters use RandenTraits; duplication in RandenSlow removed. PiperOrigin-RevId: 312190313 -- dc8b42e054046741e9ed65335bfdface997c6063 by Abseil Team <absl-team@google.com>: Internal change. PiperOrigin-RevId: 312167304 -- f13d248fafaf206492c1362c3574031aea3abaf7 by Matthew Brown <matthewbr@google.com>: Cleanup StrFormat extensions a little. PiperOrigin-RevId: 312166336 -- 9d9117589667afe2332bb7ad42bc967ca7c54502 by Derek Mauro <dmauro@google.com>: Internal change PiperOrigin-RevId: 312105213 -- 9a12b9b3aa0e59b8ee6cf9408ed0029045543a9b by Abseil Team <absl-team@google.com>: Complete IGNORE_TYPE macro renaming. PiperOrigin-RevId: 311999699 -- 64756f20d61021d999bd0d4c15e9ad3857382f57 by Gennadiy Rozental <rogeeff@google.com>: Switch to fixed bytes specific default value. This fixes the Abseil Flags for big endian platforms. PiperOrigin-RevId: 311844448 -- bdbe6b5b29791dbc3816ada1828458b3010ff1e9 by Laramie Leavitt <lar@google.com>: Change many distribution tests to use pcg_engine as a deterministic source of entropy. It's reasonable to test that the BitGen itself has good entropy, however when testing the cross product of all random distributions x all the architecture variations x all submitted changes results in a large number of tests. In order to account for these failures while still using good entropy requires that our allowed sigma need to account for all of these independent tests. Our current sigma values are too restrictive, and we see a lot of failures, so we have to either relax the sigma values or convert some of the statistical tests to use deterministic values. This changelist does the latter. PiperOrigin-RevId: 311840096 GitOrigin-RevId: f012012ef78234a6a4585321b67d7b7c92ebc266 Change-Id: Ic84886f38ff30d7d72c126e9b63c9a61eb729a1a
5 years ago
return random_internal::DistributionCaller<gen_t>::template Call<
distribution_t>(&urbg, tag, static_cast<return_t>(lo),
static_cast<return_t>(hi));
}
// absl::Uniform(bitgen, lo, hi)
//
// Overload of `Uniform()` using different (but compatible) lo, hi types and the
// default closed-open interval of [lo, hi). Note that a compile-error will
// result if the return type cannot be deduced correctly from the passed types.
template <typename R = void, typename URBG, typename A, typename B>
typename absl::enable_if_t<std::is_same<R, void>::value,
random_internal::uniform_inferred_return_t<A, B>>
Uniform(URBG&& urbg, // NOLINT(runtime/references)
A lo, B hi) {
using gen_t = absl::decay_t<URBG>;
using return_t = typename random_internal::uniform_inferred_return_t<A, B>;
using distribution_t = random_internal::UniformDistributionWrapper<return_t>;
constexpr auto tag = absl::IntervalClosedOpen;
auto a = random_internal::uniform_lower_bound<return_t>(tag, lo, hi);
auto b = random_internal::uniform_upper_bound<return_t>(tag, lo, hi);
Export of internal Abseil changes -- 790f9061df340cd900e8da70e66c363f7af3c2eb by Abseil Team <absl-team@google.com>: Add support for rvalue reference to function types. PiperOrigin-RevId: 324508531 -- 51fe201dbb41a3ebc3d49ff65250b5f464279d43 by Abseil Team <absl-team@google.com>: Cleaning up function comment style; no substantive change. PiperOrigin-RevId: 324497401 -- da8595d5266577d0c170528d12f6de17b8affcc2 by Abseil Team <absl-team@google.com>: Add support for demangling GNU vector types. PiperOrigin-RevId: 324494559 -- 0cb0acf88c1750f6963c9cb85249f9b4f0bd5104 by Abseil Team <absl-team@google.com>: Add support for thread-local types. PiperOrigin-RevId: 324491183 -- c676bc8380560599cd26f7f231e04e6be532e904 by Abseil Team <absl-team@google.com>: Add support for demangling "Du" (char8_t). PiperOrigin-RevId: 324441607 -- b218bf6467bc62b327214782c881e8224ad91509 by Abseil Team <absl-team@google.com>: Update doc comments in header of `any.h` to reflect that `absl::variant` has been released. PiperOrigin-RevId: 324431690 -- e5b579f3f1aa598c1f62e71dba7103b98811de59 by Laramie Leavitt <lar@google.com>: Bugfix: Fix bounds in absl::Uniform where one of the bounds is min/max. When absl::Uniform(rng, tag, a, b) is called, the tag is used in conjunction with the type to determine whether or not to manipulate the bounds to make them inclusive or exclusive through the uniform_*_bound functions. Unfortunately, at limits of the interval the function was not well behaved. The previous implementation used wrapping arithmetic. This causes incorrect bounds computation at the extremes (numeric_limits::min / numeric_limits::max) the bound would wrap. Improve this situation by: 1/ Changing the uniform_*_bound functions to use saturating arithmetic instead of wrapping, thus in the unsigned case, the upper_bound of IntervalOpenOpen for 0 is now 0, rather than numeric_limits::max, likewise for the lower bound. 2/ Adjusting the hi/lo checks in the distributions. When the interval is empty, such as for absl::Uniform(absl::IntervalOpenOpen, gen, 1, 0), the return value is somewhat nonsensical. Now absl::Uniform more consistently returns the low input rather than any adjusted input. In the above case, that means that 1 is returned rather than 2. NOTE: Calls to absl::Uniform where the resolved upper bound is < the lower bound are still ill-formed and should be avoided. 3/ Adding better tests. The underlying uniform_*_distribution classes are not affected. PiperOrigin-RevId: 324240873 GitOrigin-RevId: 790f9061df340cd900e8da70e66c363f7af3c2eb Change-Id: I2a2208650ea3135c575e200b868ce1d275069fc8
4 years ago
if (!random_internal::is_uniform_range_valid(a, b)) return lo;
Export of internal Abseil changes -- f012012ef78234a6a4585321b67d7b7c92ebc266 by Laramie Leavitt <lar@google.com>: Slight restructuring of absl/random/internal randen implementation. Convert round-keys.inc into randen_round_keys.cc file. Consistently use a 128-bit pointer type for internal method parameters. This allows simpler pointer arithmetic in C++ & permits removal of some constants and casts. Remove some redundancy in comments & constexpr variables. Specifically, all references to Randen algorithm parameters use RandenTraits; duplication in RandenSlow removed. PiperOrigin-RevId: 312190313 -- dc8b42e054046741e9ed65335bfdface997c6063 by Abseil Team <absl-team@google.com>: Internal change. PiperOrigin-RevId: 312167304 -- f13d248fafaf206492c1362c3574031aea3abaf7 by Matthew Brown <matthewbr@google.com>: Cleanup StrFormat extensions a little. PiperOrigin-RevId: 312166336 -- 9d9117589667afe2332bb7ad42bc967ca7c54502 by Derek Mauro <dmauro@google.com>: Internal change PiperOrigin-RevId: 312105213 -- 9a12b9b3aa0e59b8ee6cf9408ed0029045543a9b by Abseil Team <absl-team@google.com>: Complete IGNORE_TYPE macro renaming. PiperOrigin-RevId: 311999699 -- 64756f20d61021d999bd0d4c15e9ad3857382f57 by Gennadiy Rozental <rogeeff@google.com>: Switch to fixed bytes specific default value. This fixes the Abseil Flags for big endian platforms. PiperOrigin-RevId: 311844448 -- bdbe6b5b29791dbc3816ada1828458b3010ff1e9 by Laramie Leavitt <lar@google.com>: Change many distribution tests to use pcg_engine as a deterministic source of entropy. It's reasonable to test that the BitGen itself has good entropy, however when testing the cross product of all random distributions x all the architecture variations x all submitted changes results in a large number of tests. In order to account for these failures while still using good entropy requires that our allowed sigma need to account for all of these independent tests. Our current sigma values are too restrictive, and we see a lot of failures, so we have to either relax the sigma values or convert some of the statistical tests to use deterministic values. This changelist does the latter. PiperOrigin-RevId: 311840096 GitOrigin-RevId: f012012ef78234a6a4585321b67d7b7c92ebc266 Change-Id: Ic84886f38ff30d7d72c126e9b63c9a61eb729a1a
5 years ago
return random_internal::DistributionCaller<gen_t>::template Call<
distribution_t>(&urbg, static_cast<return_t>(lo),
static_cast<return_t>(hi));
}
// absl::Uniform<unsigned T>(bitgen)
//
// Overload of Uniform() using the minimum and maximum values of a given type
// `T` (which must be unsigned), returning a value of type `unsigned T`
template <typename R, typename URBG>
typename absl::enable_if_t<!std::is_signed<R>::value, R> //
Uniform(URBG&& urbg) { // NOLINT(runtime/references)
using gen_t = absl::decay_t<URBG>;
using distribution_t = random_internal::UniformDistributionWrapper<R>;
return random_internal::DistributionCaller<gen_t>::template Call<
distribution_t>(&urbg);
}
// -----------------------------------------------------------------------------
// absl::Bernoulli(bitgen, p)
// -----------------------------------------------------------------------------
//
// `absl::Bernoulli` produces a random boolean value, with probability `p`
// (where 0.0 <= p <= 1.0) equaling `true`.
//
// Prefer `absl::Bernoulli` to produce boolean values over other alternatives
// such as comparing an `absl::Uniform()` value to a specific output.
//
// See https://en.wikipedia.org/wiki/Bernoulli_distribution
//
// Example:
//
// absl::BitGen bitgen;
// ...
// if (absl::Bernoulli(bitgen, 1.0/3721.0)) {
// std::cout << "Asteroid field navigation successful.";
// }
//
template <typename URBG>
bool Bernoulli(URBG&& urbg, // NOLINT(runtime/references)
double p) {
using gen_t = absl::decay_t<URBG>;
using distribution_t = absl::bernoulli_distribution;
return random_internal::DistributionCaller<gen_t>::template Call<
distribution_t>(&urbg, p);
}
// -----------------------------------------------------------------------------
// absl::Beta<T>(bitgen, alpha, beta)
// -----------------------------------------------------------------------------
//
// `absl::Beta` produces a floating point number distributed in the closed
// interval [0,1] and parameterized by two values `alpha` and `beta` as per a
// Beta distribution. `T` must be a floating point type, but may be inferred
// from the types of `alpha` and `beta`.
//
// See https://en.wikipedia.org/wiki/Beta_distribution.
//
// Example:
//
// absl::BitGen bitgen;
// ...
// double sample = absl::Beta(bitgen, 3.0, 2.0);
//
template <typename RealType, typename URBG>
RealType Beta(URBG&& urbg, // NOLINT(runtime/references)
RealType alpha, RealType beta) {
static_assert(
std::is_floating_point<RealType>::value,
"Template-argument 'RealType' must be a floating-point type, in "
"absl::Beta<RealType, URBG>(...)");
using gen_t = absl::decay_t<URBG>;
using distribution_t = typename absl::beta_distribution<RealType>;
return random_internal::DistributionCaller<gen_t>::template Call<
distribution_t>(&urbg, alpha, beta);
}
// -----------------------------------------------------------------------------
// absl::Exponential<T>(bitgen, lambda = 1)
// -----------------------------------------------------------------------------
//
// `absl::Exponential` produces a floating point number representing the
// distance (time) between two consecutive events in a point process of events
// occurring continuously and independently at a constant average rate. `T` must
// be a floating point type, but may be inferred from the type of `lambda`.
//
// See https://en.wikipedia.org/wiki/Exponential_distribution.
//
// Example:
//
// absl::BitGen bitgen;
// ...
// double call_length = absl::Exponential(bitgen, 7.0);
//
template <typename RealType, typename URBG>
RealType Exponential(URBG&& urbg, // NOLINT(runtime/references)
RealType lambda = 1) {
static_assert(
std::is_floating_point<RealType>::value,
"Template-argument 'RealType' must be a floating-point type, in "
"absl::Exponential<RealType, URBG>(...)");
using gen_t = absl::decay_t<URBG>;
using distribution_t = typename absl::exponential_distribution<RealType>;
return random_internal::DistributionCaller<gen_t>::template Call<
distribution_t>(&urbg, lambda);
}
// -----------------------------------------------------------------------------
// absl::Gaussian<T>(bitgen, mean = 0, stddev = 1)
// -----------------------------------------------------------------------------
//
// `absl::Gaussian` produces a floating point number selected from the Gaussian
// (ie. "Normal") distribution. `T` must be a floating point type, but may be
// inferred from the types of `mean` and `stddev`.
//
// See https://en.wikipedia.org/wiki/Normal_distribution
//
// Example:
//
// absl::BitGen bitgen;
// ...
// double giraffe_height = absl::Gaussian(bitgen, 16.3, 3.3);
//
template <typename RealType, typename URBG>
RealType Gaussian(URBG&& urbg, // NOLINT(runtime/references)
RealType mean = 0, RealType stddev = 1) {
static_assert(
std::is_floating_point<RealType>::value,
"Template-argument 'RealType' must be a floating-point type, in "
"absl::Gaussian<RealType, URBG>(...)");
using gen_t = absl::decay_t<URBG>;
using distribution_t = typename absl::gaussian_distribution<RealType>;
return random_internal::DistributionCaller<gen_t>::template Call<
distribution_t>(&urbg, mean, stddev);
}
// -----------------------------------------------------------------------------
// absl::LogUniform<T>(bitgen, lo, hi, base = 2)
// -----------------------------------------------------------------------------
//
// `absl::LogUniform` produces random values distributed where the log to a
// given base of all values is uniform in a closed interval [lo, hi]. `T` must
// be an integral type, but may be inferred from the types of `lo` and `hi`.
//
// I.e., `LogUniform(0, n, b)` is uniformly distributed across buckets
// [0], [1, b-1], [b, b^2-1] .. [b^(k-1), (b^k)-1] .. [b^floor(log(n, b)), n]
// and is uniformly distributed within each bucket.
//
// The resulting probability density is inversely related to bucket size, though
// values in the final bucket may be more likely than previous values. (In the
// extreme case where n = b^i the final value will be tied with zero as the most
// probable result.
//
// If `lo` is nonzero then this distribution is shifted to the desired interval,
// so LogUniform(lo, hi, b) is equivalent to LogUniform(0, hi-lo, b)+lo.
//
// See http://ecolego.facilia.se/ecolego/show/Log-Uniform%20Distribution
//
// Example:
//
// absl::BitGen bitgen;
// ...
// int v = absl::LogUniform(bitgen, 0, 1000);
//
template <typename IntType, typename URBG>
IntType LogUniform(URBG&& urbg, // NOLINT(runtime/references)
IntType lo, IntType hi, IntType base = 2) {
static_assert(std::is_integral<IntType>::value,
"Template-argument 'IntType' must be an integral type, in "
"absl::LogUniform<IntType, URBG>(...)");
using gen_t = absl::decay_t<URBG>;
using distribution_t = typename absl::log_uniform_int_distribution<IntType>;
return random_internal::DistributionCaller<gen_t>::template Call<
distribution_t>(&urbg, lo, hi, base);
}
// -----------------------------------------------------------------------------
// absl::Poisson<T>(bitgen, mean = 1)
// -----------------------------------------------------------------------------
//
// `absl::Poisson` produces discrete probabilities for a given number of events
// occurring within a fixed interval within the closed interval [0, max]. `T`
// must be an integral type.
//
// See https://en.wikipedia.org/wiki/Poisson_distribution
//
// Example:
//
// absl::BitGen bitgen;
// ...
// int requests_per_minute = absl::Poisson<int>(bitgen, 3.2);
//
template <typename IntType, typename URBG>
IntType Poisson(URBG&& urbg, // NOLINT(runtime/references)
double mean = 1.0) {
static_assert(std::is_integral<IntType>::value,
"Template-argument 'IntType' must be an integral type, in "
"absl::Poisson<IntType, URBG>(...)");
using gen_t = absl::decay_t<URBG>;
using distribution_t = typename absl::poisson_distribution<IntType>;
return random_internal::DistributionCaller<gen_t>::template Call<
distribution_t>(&urbg, mean);
}
// -----------------------------------------------------------------------------
// absl::Zipf<T>(bitgen, hi = max, q = 2, v = 1)
// -----------------------------------------------------------------------------
//
// `absl::Zipf` produces discrete probabilities commonly used for modelling of
// rare events over the closed interval [0, hi]. The parameters `v` and `q`
// determine the skew of the distribution. `T` must be an integral type, but
// may be inferred from the type of `hi`.
//
// See http://mathworld.wolfram.com/ZipfDistribution.html
//
// Example:
//
// absl::BitGen bitgen;
// ...
// int term_rank = absl::Zipf<int>(bitgen);
//
template <typename IntType, typename URBG>
IntType Zipf(URBG&& urbg, // NOLINT(runtime/references)
IntType hi = (std::numeric_limits<IntType>::max)(), double q = 2.0,
double v = 1.0) {
static_assert(std::is_integral<IntType>::value,
"Template-argument 'IntType' must be an integral type, in "
"absl::Zipf<IntType, URBG>(...)");
using gen_t = absl::decay_t<URBG>;
using distribution_t = typename absl::zipf_distribution<IntType>;
return random_internal::DistributionCaller<gen_t>::template Call<
distribution_t>(&urbg, hi, q, v);
}
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_RANDOM_DISTRIBUTIONS_H_