summaryrefslogtreecommitdiff
path: root/absl/random
diff options
context:
space:
mode:
authorGravatar Abseil Team <absl-team@google.com>2019-10-23 19:35:39 -0700
committerGravatar Derek Mauro <dmauro@google.com>2019-10-24 10:29:13 -0400
commit078b89b3c046d230ef3ad39494e5852184eb528b (patch)
tree90368e0b398c3e43196c823504b88ab78a8408b3 /absl/random
parent19b021cb3ff23048dfbe236a4e611925d8930831 (diff)
Export of internal Abseil changes
-- e54b9c7bbb0c58475676c268e2e19c69f4bce48a by Jorg Brown <jorg@google.com>: Tweak ABSL_PREDICT_TRUE slightly, for better code on some platforms and/or optimization levels. "false || (x)" is more verbose than "!!(x)", but ultimately more efficient. For example, given this code: void InitIfNecessary() { if (ABSL_PREDICT_TRUE(NeedsInit())) { SlowInitIfNecessary(); } } Clang with default optimization level will produce: Before this CL After this CL InitIfNecessary: InitIfNecessary: push rbp push rbp mov rbp, rsp mov rbp, rsp call NeedsInit call NeedsInit xor al, -1 xor al, -1 test al, 1 test al, 1 jne .LBB2_1 jne .LBB3_1 jmp .LBB2_2 jmp .LBB3_2 .LBB2_1: .LBB3_1: call SlowInitIfNecessary call SlowInitIfNecessary .LBB2_2: .LBB3_2: pop rbp pop rbp ret ret PiperOrigin-RevId: 276401386 -- 0a3c4dfd8342bf2b1b11a87f1c662c883f73cab7 by Abseil Team <absl-team@google.com>: Fix comment nit: sem_open => sem_init. The code calls sem_init, not sem_open, to initialize an unnamed semaphore. (sem_open creates or opens a named semaphore.) PiperOrigin-RevId: 276344072 -- b36a664e9459057509a90e83d3482e1d3a4c44c7 by Abseil Team <absl-team@google.com>: Fix typo in flat_hash_map.h: exchaged -> exchanged PiperOrigin-RevId: 276295792 -- 7bbd8d18276eb110c8335743e35fceb662ddf3d6 by Samuel Benzaquen <sbenza@google.com>: Add assertions to verify use of iterators. PiperOrigin-RevId: 276283300 -- 677398a8ffcb1f59182cffe57a4fe7ff147a0404 by Laramie Leavitt <lar@google.com>: Migrate distribution_impl.h/cc to generate_real.h/cc. Combine the methods RandU64To<Float,Double> into a single method: GenerateRealFromBits(). Remove rejection sampling from absl::uniform_real_distribution. PiperOrigin-RevId: 276158675 -- c60c9d11d24b0c546329d998e78e15a84b3153f5 by Abseil Team <absl-team@google.com>: Internal change PiperOrigin-RevId: 276126962 -- 4c840cab6a8d86efa29b397cafaf7520eece68cc by Andy Soffer <asoffer@google.com>: Update CMakeLists.txt to address https://github.com/abseil/abseil-cpp/issues/365. This does not cover every platform, but it does at least address the first-order issue of assuming gcc implies x86. PiperOrigin-RevId: 276116253 -- 98da366e6b5d51afe5d7ac6722126aca23d85ee6 by Abseil Team <absl-team@google.com>: Internal change PiperOrigin-RevId: 276097452 GitOrigin-RevId: e54b9c7bbb0c58475676c268e2e19c69f4bce48a Change-Id: I02d84454bb71ab21ad3d39650acf6cc6e36f58d7
Diffstat (limited to 'absl/random')
-rw-r--r--absl/random/BUILD.bazel2
-rw-r--r--absl/random/CMakeLists.txt17
-rw-r--r--absl/random/beta_distribution.h31
-rw-r--r--absl/random/beta_distribution_test.cc2
-rw-r--r--absl/random/exponential_distribution.h14
-rw-r--r--absl/random/gaussian_distribution.h22
-rw-r--r--absl/random/internal/BUILD.bazel16
-rw-r--r--absl/random/internal/distribution_impl.h194
-rw-r--r--absl/random/internal/generate_real.h144
-rw-r--r--absl/random/internal/generate_real_test.cc (renamed from absl/random/internal/distribution_impl_test.cc)111
-rw-r--r--absl/random/log_uniform_int_distribution.h2
-rw-r--r--absl/random/poisson_distribution.h20
-rw-r--r--absl/random/uniform_int_distribution.h1
-rw-r--r--absl/random/uniform_real_distribution.h15
14 files changed, 304 insertions, 287 deletions
diff --git a/absl/random/BUILD.bazel b/absl/random/BUILD.bazel
index 828f1348..c3520df8 100644
--- a/absl/random/BUILD.bazel
+++ b/absl/random/BUILD.bazel
@@ -69,10 +69,10 @@ cc_library(
"//absl/base:base_internal",
"//absl/base:core_headers",
"//absl/meta:type_traits",
- "//absl/random/internal:distribution_impl",
"//absl/random/internal:distributions",
"//absl/random/internal:fast_uniform_bits",
"//absl/random/internal:fastmath",
+ "//absl/random/internal:generate_real",
"//absl/random/internal:iostream_state_saver",
"//absl/random/internal:traits",
"//absl/random/internal:uniform_helper",
diff --git a/absl/random/CMakeLists.txt b/absl/random/CMakeLists.txt
index 19dd2cab..289854ff 100644
--- a/absl/random/CMakeLists.txt
+++ b/absl/random/CMakeLists.txt
@@ -58,7 +58,7 @@ absl_cc_library(
DEPS
absl::base_internal
absl::core_headers
- absl::random_internal_distribution_impl
+ absl::random_internal_generate_real
absl::random_internal_distributions
absl::random_internal_fast_uniform_bits
absl::random_internal_fastmath
@@ -543,19 +543,18 @@ absl_cc_library(
# Internal-only target, do not depend on directly.
absl_cc_library(
NAME
- random_internal_distribution_impl
+ random_internal_generate_real
HDRS
- "internal/distribution_impl.h"
+ "internal/generate_real.h"
COPTS
${ABSL_DEFAULT_COPTS}
LINKOPTS
${ABSL_DEFAULT_LINKOPTS}
DEPS
absl::bits
- absl::config
- absl::int128
absl::random_internal_fastmath
absl::random_internal_traits
+ absl::type_traits
)
# Internal-only target, do not depend on directly.
@@ -767,9 +766,9 @@ absl_cc_test(
# Internal-only target, do not depend on directly.
absl_cc_test(
NAME
- random_internal_distribution_impl_test
+ random_internal_generate_real_test
SRCS
- "internal/distribution_impl_test.cc"
+ "internal/generate_real_test.cc"
COPTS
${ABSL_TEST_COPTS}
LINKOPTS
@@ -777,8 +776,7 @@ absl_cc_test(
DEPS
absl::bits
absl::flags
- absl::int128
- absl::random_internal_distribution_impl
+ absl::random_internal_generate_real
gtest_main
)
@@ -1029,7 +1027,6 @@ absl_cc_library(
${ABSL_DEFAULT_LINKOPTS}
DEPS
absl::core_headers
- absl::random_internal_distribution_impl
absl::random_internal_fast_uniform_bits
absl::random_internal_iostream_state_saver
absl::random_internal_traits
diff --git a/absl/random/beta_distribution.h b/absl/random/beta_distribution.h
index e29894f2..b09b02f0 100644
--- a/absl/random/beta_distribution.h
+++ b/absl/random/beta_distribution.h
@@ -22,9 +22,10 @@
#include <ostream>
#include <type_traits>
-#include "absl/random/internal/distribution_impl.h"
+#include "absl/meta/type_traits.h"
#include "absl/random/internal/fast_uniform_bits.h"
#include "absl/random/internal/fastmath.h"
+#include "absl/random/internal/generate_real.h"
#include "absl/random/internal/iostream_state_saver.h"
namespace absl {
@@ -275,15 +276,21 @@ typename beta_distribution<RealType>::result_type
beta_distribution<RealType>::AlgorithmJoehnk(
URBG& g, // NOLINT(runtime/references)
const param_type& p) {
+ using random_internal::GeneratePositiveTag;
+ using random_internal::GenerateRealFromBits;
+ using real_type =
+ absl::conditional_t<std::is_same<RealType, float>::value, float, double>;
+
// Based on Joehnk, M. D. Erzeugung von betaverteilten und gammaverteilten
// Zufallszahlen. Metrika 8.1 (1964): 5-15.
// This method is described in Knuth, Vol 2 (Third Edition), pp 134.
- using RandU64ToReal = typename random_internal::RandU64ToReal<result_type>;
- using random_internal::PositiveValueT;
+
result_type u, v, x, y, z;
for (;;) {
- u = RandU64ToReal::template Value<PositiveValueT, false>(fast_u64_(g));
- v = RandU64ToReal::template Value<PositiveValueT, false>(fast_u64_(g));
+ u = GenerateRealFromBits<real_type, GeneratePositiveTag, false>(
+ fast_u64_(g));
+ v = GenerateRealFromBits<real_type, GeneratePositiveTag, false>(
+ fast_u64_(g));
// Direct method. std::pow is slow for float, so rely on the optimizer to
// remove the std::pow() path for that case.
@@ -327,12 +334,14 @@ typename beta_distribution<RealType>::result_type
beta_distribution<RealType>::AlgorithmCheng(
URBG& g, // NOLINT(runtime/references)
const param_type& p) {
+ using random_internal::GeneratePositiveTag;
+ using random_internal::GenerateRealFromBits;
+ using real_type =
+ absl::conditional_t<std::is_same<RealType, float>::value, float, double>;
+
// Based on Cheng, Russell CH. Generating beta variates with nonintegral
// shape parameters. Communications of the ACM 21.4 (1978): 317-322.
// (https://dl.acm.org/citation.cfm?id=359482).
- using RandU64ToReal = typename random_internal::RandU64ToReal<result_type>;
- using random_internal::PositiveValueT;
-
static constexpr result_type kLogFour =
result_type(1.3862943611198906188344642429163531361); // log(4)
static constexpr result_type kS =
@@ -341,8 +350,10 @@ beta_distribution<RealType>::AlgorithmCheng(
const bool use_algorithm_ba = (p.method_ == param_type::CHENG_BA);
result_type u1, u2, v, w, z, r, s, t, bw_inv, lhs;
for (;;) {
- u1 = RandU64ToReal::template Value<PositiveValueT, false>(fast_u64_(g));
- u2 = RandU64ToReal::template Value<PositiveValueT, false>(fast_u64_(g));
+ u1 = GenerateRealFromBits<real_type, GeneratePositiveTag, false>(
+ fast_u64_(g));
+ u2 = GenerateRealFromBits<real_type, GeneratePositiveTag, false>(
+ fast_u64_(g));
v = p.y_ * std::log(u1 / (1 - u1));
w = p.a_ * std::exp(v);
bw_inv = result_type(1) / (p.b_ + w);
diff --git a/absl/random/beta_distribution_test.cc b/absl/random/beta_distribution_test.cc
index 966ad08b..d0111b3e 100644
--- a/absl/random/beta_distribution_test.cc
+++ b/absl/random/beta_distribution_test.cc
@@ -92,7 +92,7 @@ TYPED_TEST(BetaDistributionInterfaceTest, SerializeTest) {
for (TypeParam alpha : kValues) {
for (TypeParam beta : kValues) {
ABSL_INTERNAL_LOG(
- INFO, absl::StrFormat("Smoke test for Beta(%f, %f)", alpha, beta));
+ INFO, absl::StrFormat("Smoke test for Beta(%a, %a)", alpha, beta));
param_type param(alpha, beta);
absl::beta_distribution<TypeParam> before(alpha, beta);
diff --git a/absl/random/exponential_distribution.h b/absl/random/exponential_distribution.h
index c8af1975..24abf57e 100644
--- a/absl/random/exponential_distribution.h
+++ b/absl/random/exponential_distribution.h
@@ -21,8 +21,9 @@
#include <limits>
#include <type_traits>
-#include "absl/random/internal/distribution_impl.h"
+#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 {
@@ -118,9 +119,14 @@ typename exponential_distribution<RealType>::result_type
exponential_distribution<RealType>::operator()(
URBG& g, // NOLINT(runtime/references)
const param_type& p) {
- using random_internal::NegativeValueT;
- const result_type u = random_internal::RandU64ToReal<
- result_type>::template Value<NegativeValueT, false>(fast_u64_(g));
+ using random_internal::GenerateNegativeTag;
+ using random_internal::GenerateRealFromBits;
+ using real_type =
+ absl::conditional_t<std::is_same<RealType, float>::value, float, double>;
+
+ const result_type u = GenerateRealFromBits<real_type, GenerateNegativeTag,
+ false>(fast_u64_(g)); // U(-1, 0)
+
// log1p(-x) is mathematically equivalent to log(1 - x) but has more
// accuracy for x near zero.
return p.neg_inv_lambda_ * std::log1p(u);
diff --git a/absl/random/gaussian_distribution.h b/absl/random/gaussian_distribution.h
index 1d1347bc..c299e944 100644
--- a/absl/random/gaussian_distribution.h
+++ b/absl/random/gaussian_distribution.h
@@ -28,8 +28,8 @@
#include <limits>
#include <type_traits>
-#include "absl/random/internal/distribution_impl.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 {
@@ -207,12 +207,18 @@ namespace random_internal {
template <typename URBG>
inline double gaussian_distribution_base::zignor_fallback(URBG& g, bool neg) {
+ using random_internal::GeneratePositiveTag;
+ using random_internal::GenerateRealFromBits;
+
// This fallback path happens approximately 0.05% of the time.
double x, y;
do {
// kRInv = 1/r, U(0, 1)
- x = kRInv * std::log(RandU64ToDouble<PositiveValueT, false>(fast_u64_(g)));
- y = -std::log(RandU64ToDouble<PositiveValueT, false>(fast_u64_(g)));
+ x = kRInv *
+ std::log(GenerateRealFromBits<double, GeneratePositiveTag, false>(
+ fast_u64_(g)));
+ y = -std::log(
+ GenerateRealFromBits<double, GeneratePositiveTag, false>(fast_u64_(g)));
} while ((y + y) < (x * x));
return neg ? (x - kR) : (kR - x);
}
@@ -220,6 +226,10 @@ inline double gaussian_distribution_base::zignor_fallback(URBG& g, bool neg) {
template <typename URBG>
inline double gaussian_distribution_base::zignor(
URBG& g) { // NOLINT(runtime/references)
+ using random_internal::GeneratePositiveTag;
+ using random_internal::GenerateRealFromBits;
+ using random_internal::GenerateSignedTag;
+
while (true) {
// We use a single uint64_t to generate both a double and a strip.
// These bits are unused when the generated double is > 1/2^5.
@@ -227,7 +237,8 @@ inline double gaussian_distribution_base::zignor(
// values (those smaller than 1/2^5, which all end up on the left tail).
uint64_t bits = fast_u64_(g);
int i = static_cast<int>(bits & kMask); // pick a random strip
- double j = RandU64ToDouble<SignedValueT, false>(bits); // U(-1, 1)
+ double j = GenerateRealFromBits<double, GenerateSignedTag, false>(
+ bits); // U(-1, 1)
const double x = j * zg_.x[i];
// Retangular box. Handles >97% of all cases.
@@ -244,7 +255,8 @@ inline double gaussian_distribution_base::zignor(
}
// i > 0: Wedge samples using precomputed values.
- double v = RandU64ToDouble<PositiveValueT, false>(fast_u64_(g)); // U(0, 1)
+ double v = GenerateRealFromBits<double, GeneratePositiveTag, false>(
+ fast_u64_(g)); // U(0, 1)
if ((zg_.f[i + 1] + v * (zg_.f[i] - zg_.f[i + 1])) <
std::exp(-0.5 * x * x)) {
return x;
diff --git a/absl/random/internal/BUILD.bazel b/absl/random/internal/BUILD.bazel
index ec58cecd..91388d19 100644
--- a/absl/random/internal/BUILD.bazel
+++ b/absl/random/internal/BUILD.bazel
@@ -175,9 +175,9 @@ cc_library(
)
cc_library(
- name = "distribution_impl",
+ name = "generate_real",
hdrs = [
- "distribution_impl.h",
+ "generate_real.h",
],
copts = ABSL_DEFAULT_COPTS,
linkopts = ABSL_DEFAULT_LINKOPTS,
@@ -185,8 +185,7 @@ cc_library(
":fastmath",
":traits",
"//absl/base:bits",
- "//absl/base:config",
- "//absl/numeric:int128",
+ "//absl/meta:type_traits",
],
)
@@ -398,16 +397,17 @@ cc_test(
)
cc_test(
- name = "distribution_impl_test",
+ name = "generate_real_test",
size = "small",
- srcs = ["distribution_impl_test.cc"],
+ srcs = [
+ "generate_real_test.cc",
+ ],
copts = ABSL_TEST_COPTS,
linkopts = ABSL_DEFAULT_LINKOPTS,
deps = [
- ":distribution_impl",
+ ":generate_real",
"//absl/base:bits",
"//absl/flags:flag",
- "//absl/numeric:int128",
"@com_google_googletest//:gtest_main",
],
)
diff --git a/absl/random/internal/distribution_impl.h b/absl/random/internal/distribution_impl.h
deleted file mode 100644
index 49b3e1a6..00000000
--- a/absl/random/internal/distribution_impl.h
+++ /dev/null
@@ -1,194 +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.
-
-#ifndef ABSL_RANDOM_INTERNAL_DISTRIBUTION_IMPL_H_
-#define ABSL_RANDOM_INTERNAL_DISTRIBUTION_IMPL_H_
-
-// This file contains some implementation details which are used by one or more
-// of the absl random number distributions.
-
-#include <cfloat>
-#include <cstddef>
-#include <cstdint>
-#include <cstring>
-#include <limits>
-#include <type_traits>
-
-#if (defined(_WIN32) || defined(_WIN64)) && defined(_M_IA64)
-#include <intrin.h> // NOLINT(build/include_order)
-#pragma intrinsic(_umul128)
-#define ABSL_INTERNAL_USE_UMUL128 1
-#endif
-
-#include "absl/base/config.h"
-#include "absl/base/internal/bits.h"
-#include "absl/numeric/int128.h"
-#include "absl/random/internal/fastmath.h"
-#include "absl/random/internal/traits.h"
-
-namespace absl {
-namespace random_internal {
-
-// Creates a double from `bits`, with the template fields controlling the
-// output.
-//
-// RandU64To is both more efficient and generates more unique values in the
-// result interval than known implementations of std::generate_canonical().
-//
-// The `Signed` parameter controls whether positive, negative, or both are
-// returned (thus affecting the output interval).
-// When Signed == SignedValueT, range is U(-1, 1)
-// When Signed == NegativeValueT, range is U(-1, 0)
-// When Signed == PositiveValueT, range is U(0, 1)
-//
-// When the `IncludeZero` parameter is true, the function may return 0 for some
-// inputs, otherwise it never returns 0.
-//
-// The `ExponentBias` parameter determines the scale of the output range by
-// adjusting the exponent.
-//
-// When a value in U(0,1) is required, use:
-// RandU64ToDouble<PositiveValueT, true, 0>();
-//
-// When a value in U(-1,1) is required, use:
-// RandU64ToDouble<SignedValueT, false, 0>() => U(-1, 1)
-// This generates more distinct values than the mathematically equivalent
-// expression `U(0, 1) * 2.0 - 1.0`, and is preferable.
-//
-// Scaling the result by powers of 2 (and avoiding a multiply) is also possible:
-// RandU64ToDouble<PositiveValueT, false, 1>(); => U(0, 2)
-// RandU64ToDouble<PositiveValueT, false, -1>(); => U(0, 0.5)
-//
-
-// Tristate types controlling the output.
-struct PositiveValueT {};
-struct NegativeValueT {};
-struct SignedValueT {};
-
-// RandU64ToDouble is the double-result variant of RandU64To, described above.
-template <typename Signed, bool IncludeZero, int ExponentBias = 0>
-inline double RandU64ToDouble(uint64_t bits) {
- static_assert(std::is_same<Signed, PositiveValueT>::value ||
- std::is_same<Signed, NegativeValueT>::value ||
- std::is_same<Signed, SignedValueT>::value,
- "");
-
- // Maybe use the left-most bit for a sign bit.
- uint64_t sign = std::is_same<Signed, NegativeValueT>::value
- ? 0x8000000000000000ull
- : 0; // Sign bits.
-
- if (std::is_same<Signed, SignedValueT>::value) {
- sign = bits & 0x8000000000000000ull;
- bits = bits & 0x7FFFFFFFFFFFFFFFull;
- }
- if (IncludeZero) {
- if (bits == 0u) return 0;
- }
-
- // Number of leading zeros is mapped to the exponent: 2^-clz
- int clz = base_internal::CountLeadingZeros64(bits);
- // Shift number left to erase leading zeros.
- bits <<= IncludeZero ? clz : (clz & 63);
-
- // Shift number right to remove bits that overflow double mantissa. The
- // direction of the shift depends on `clz`.
- bits >>= (64 - DBL_MANT_DIG);
-
- // Compute IEEE 754 double exponent.
- // In the Signed case, bits is a 63-bit number with a 0 msb. Adjust the
- // exponent to account for that.
- const uint64_t exp =
- (std::is_same<Signed, SignedValueT>::value ? 1023U : 1022U) +
- static_cast<uint64_t>(ExponentBias - clz);
- constexpr int kExp = DBL_MANT_DIG - 1;
- // Construct IEEE 754 double from exponent and mantissa.
- const uint64_t val = sign | (exp << kExp) | (bits & ((1ULL << kExp) - 1U));
-
- double res;
- static_assert(sizeof(res) == sizeof(val), "double is not 64 bit");
- // Memcpy value from "val" to "res" to avoid aliasing problems. Assumes that
- // endian-ness is same for double and uint64_t.
- std::memcpy(&res, &val, sizeof(res));
-
- return res;
-}
-
-// RandU64ToFloat is the float-result variant of RandU64To, described above.
-template <typename Signed, bool IncludeZero, int ExponentBias = 0>
-inline float RandU64ToFloat(uint64_t bits) {
- static_assert(std::is_same<Signed, PositiveValueT>::value ||
- std::is_same<Signed, NegativeValueT>::value ||
- std::is_same<Signed, SignedValueT>::value,
- "");
-
- // Maybe use the left-most bit for a sign bit.
- uint64_t sign = std::is_same<Signed, NegativeValueT>::value
- ? 0x80000000ul
- : 0; // Sign bits.
-
- if (std::is_same<Signed, SignedValueT>::value) {
- uint64_t a = bits & 0x8000000000000000ull;
- sign = static_cast<uint32_t>(a >> 32);
- bits = bits & 0x7FFFFFFFFFFFFFFFull;
- }
- if (IncludeZero) {
- if (bits == 0u) return 0;
- }
-
- // Number of leading zeros is mapped to the exponent: 2^-clz
- int clz = base_internal::CountLeadingZeros64(bits);
- // Shift number left to erase leading zeros.
- bits <<= IncludeZero ? clz : (clz & 63);
- // Shift number right to remove bits that overflow double mantissa. The
- // direction of the shift depends on `clz`.
- bits >>= (64 - FLT_MANT_DIG);
-
- // Construct IEEE 754 float exponent.
- // In the Signed case, bits is a 63-bit number with a 0 msb. Adjust the
- // exponent to account for that.
- const uint32_t exp =
- (std::is_same<Signed, SignedValueT>::value ? 127U : 126U) +
- static_cast<uint32_t>(ExponentBias - clz);
- constexpr int kExp = FLT_MANT_DIG - 1;
- const uint32_t val = sign | (exp << kExp) | (bits & ((1U << kExp) - 1U));
-
- float res;
- static_assert(sizeof(res) == sizeof(val), "float is not 32 bit");
- // Assumes that endian-ness is same for float and uint32_t.
- std::memcpy(&res, &val, sizeof(res));
-
- return res;
-}
-
-template <typename Result>
-struct RandU64ToReal {
- template <typename Signed, bool IncludeZero, int ExponentBias = 0>
- static inline Result Value(uint64_t bits) {
- return RandU64ToDouble<Signed, IncludeZero, ExponentBias>(bits);
- }
-};
-
-template <>
-struct RandU64ToReal<float> {
- template <typename Signed, bool IncludeZero, int ExponentBias = 0>
- static inline float Value(uint64_t bits) {
- return RandU64ToFloat<Signed, IncludeZero, ExponentBias>(bits);
- }
-};
-
-} // namespace random_internal
-} // namespace absl
-
-#endif // ABSL_RANDOM_INTERNAL_DISTRIBUTION_IMPL_H_
diff --git a/absl/random/internal/generate_real.h b/absl/random/internal/generate_real.h
new file mode 100644
index 00000000..246d863e
--- /dev/null
+++ b/absl/random/internal/generate_real.h
@@ -0,0 +1,144 @@
+// 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.
+
+#ifndef ABSL_RANDOM_INTERNAL_GENERATE_REAL_H_
+#define ABSL_RANDOM_INTERNAL_GENERATE_REAL_H_
+
+// This file contains some implementation details which are used by one or more
+// of the absl random number distributions.
+
+#include <cstdint>
+#include <cstring>
+#include <limits>
+#include <type_traits>
+
+#include "absl/base/internal/bits.h"
+#include "absl/meta/type_traits.h"
+#include "absl/random/internal/fastmath.h"
+#include "absl/random/internal/traits.h"
+
+namespace absl {
+namespace random_internal {
+
+// Tristate tag types controlling the output of GenerateRealFromBits.
+struct GeneratePositiveTag {};
+struct GenerateNegativeTag {};
+struct GenerateSignedTag {};
+
+// GenerateRealFromBits generates a single real value from a single 64-bit
+// `bits` with template fields controlling the output.
+//
+// The `SignedTag` parameter controls whether positive, negative,
+// or either signed/unsigned may be returned.
+// When SignedTag == GeneratePositiveTag, range is U(0, 1)
+// When SignedTag == GenerateNegativeTag, range is U(-1, 0)
+// When SignedTag == GenerateSignedTag, range is U(-1, 1)
+//
+// When the `IncludeZero` parameter is true, the function may return 0 for some
+// inputs, otherwise it never returns 0.
+//
+// When a value in U(0,1) is required, use:
+// Uniform64ToReal<double, PositiveValueT, true>;
+//
+// When a value in U(-1,1) is required, use:
+// Uniform64ToReal<double, SignedValueT, false>;
+//
+// This generates more distinct values than the mathematical equivalent
+// `U(0, 1) * 2.0 - 1.0`.
+//
+// Scaling the result by powers of 2 (and avoiding a multiply) is also possible:
+// GenerateRealFromBits<double>(..., -1); => U(0, 0.5)
+// GenerateRealFromBits<double>(..., 1); => U(0, 2)
+//
+template <typename RealType, // Real type, either float or double.
+ typename SignedTag = GeneratePositiveTag, // Whether a positive,
+ // negative, or signed
+ // value is generated.
+ bool IncludeZero = true>
+inline RealType GenerateRealFromBits(uint64_t bits, int exp_bias = 0) {
+ using real_type = RealType;
+ using uint_type = absl::conditional_t<std::is_same<real_type, float>::value,
+ uint32_t, uint64_t>;
+
+ static_assert(
+ (std::is_same<double, real_type>::value ||
+ std::is_same<float, real_type>::value),
+ "GenerateRealFromBits must be parameterized by either float or double.");
+
+ static_assert(sizeof(uint_type) == sizeof(real_type),
+ "Mismatched unsinged and real types.");
+
+ static_assert((std::numeric_limits<real_type>::is_iec559 &&
+ std::numeric_limits<real_type>::radix == 2),
+ "RealType representation is not IEEE 754 binary.");
+
+ static_assert((std::is_same<SignedTag, GeneratePositiveTag>::value ||
+ std::is_same<SignedTag, GenerateNegativeTag>::value ||
+ std::is_same<SignedTag, GenerateSignedTag>::value),
+ "");
+
+ static constexpr int kExp = std::numeric_limits<real_type>::digits - 1;
+ static constexpr uint_type kMask = (static_cast<uint_type>(1) << kExp) - 1u;
+ static constexpr int kUintBits = sizeof(uint_type) * 8;
+
+ int exp = exp_bias + int{std::numeric_limits<real_type>::max_exponent - 2};
+
+ // Determine the sign bit.
+ // Depending on the SignedTag, this may use the left-most bit
+ // or it may be a constant value.
+ uint_type sign = std::is_same<SignedTag, GenerateNegativeTag>::value
+ ? (static_cast<uint_type>(1) << (kUintBits - 1))
+ : 0;
+ if (std::is_same<SignedTag, GenerateSignedTag>::value) {
+ if (std::is_same<uint_type, uint64_t>::value) {
+ sign = bits & uint64_t{0x8000000000000000};
+ }
+ if (std::is_same<uint_type, uint32_t>::value) {
+ const uint64_t tmp = bits & uint64_t{0x8000000000000000};
+ sign = static_cast<uint32_t>(tmp >> 32);
+ }
+ // adjust the bits and the exponent to account for removing
+ // the leading bit.
+ bits = bits & uint64_t{0x7FFFFFFFFFFFFFFF};
+ exp++;
+ }
+ if (IncludeZero) {
+ if (bits == 0u) return 0;
+ }
+
+ // Number of leading zeros is mapped to the exponent: 2^-clz
+ // bits is 0..01xxxxxx. After shifting, we're left with 1xxx...0..0
+ int clz = base_internal::CountLeadingZeros64(bits);
+ bits <<= (IncludeZero ? clz : (clz & 63)); // remove 0-bits.
+ exp -= clz; // set the exponent.
+ bits >>= (63 - kExp);
+
+ // Construct the 32-bit or 64-bit IEEE 754 floating-point value from
+ // the individual fields: sign, exp, mantissa(bits).
+ uint_type val =
+ (std::is_same<SignedTag, GeneratePositiveTag>::value ? 0u : sign) |
+ (static_cast<uint_type>(exp) << kExp) |
+ (static_cast<uint_type>(bits) & kMask);
+
+ // bit_cast to the output-type
+ real_type result;
+ memcpy(static_cast<void*>(&result), static_cast<const void*>(&val),
+ sizeof(result));
+ return result;
+}
+
+} // namespace random_internal
+} // namespace absl
+
+#endif // ABSL_RANDOM_INTERNAL_GENERATE_REAL_H_
diff --git a/absl/random/internal/distribution_impl_test.cc b/absl/random/internal/generate_real_test.cc
index fcc16904..aa02f0c2 100644
--- a/absl/random/internal/distribution_impl_test.cc
+++ b/absl/random/internal/generate_real_test.cc
@@ -12,57 +12,74 @@
// See the License for the specific language governing permissions and
// limitations under the License.
-#include "absl/random/internal/distribution_impl.h"
+#include "absl/random/internal/generate_real.h"
+
+#include <cfloat>
+#include <cstddef>
+#include <cstdint>
+#include <string>
#include "gtest/gtest.h"
#include "absl/base/internal/bits.h"
#include "absl/flags/flag.h"
-#include "absl/numeric/int128.h"
ABSL_FLAG(int64_t, absl_random_test_trials, 50000,
"Number of trials for the probability tests.");
-using absl::random_internal::NegativeValueT;
-using absl::random_internal::PositiveValueT;
-using absl::random_internal::RandU64ToDouble;
-using absl::random_internal::RandU64ToFloat;
-using absl::random_internal::SignedValueT;
+using absl::random_internal::GenerateNegativeTag;
+using absl::random_internal::GeneratePositiveTag;
+using absl::random_internal::GenerateRealFromBits;
+using absl::random_internal::GenerateSignedTag;
namespace {
-TEST(DistributionImplTest, U64ToFloat_Positive_NoZero_Test) {
+TEST(GenerateRealTest, U64ToFloat_Positive_NoZero_Test) {
auto ToFloat = [](uint64_t a) {
- return RandU64ToFloat<PositiveValueT, false>(a);
+ return GenerateRealFromBits<float, GeneratePositiveTag, false>(a);
};
EXPECT_EQ(ToFloat(0x0000000000000000), 2.710505431e-20f);
EXPECT_EQ(ToFloat(0x0000000000000001), 5.421010862e-20f);
EXPECT_EQ(ToFloat(0x8000000000000000), 0.5);
+ EXPECT_EQ(ToFloat(0x8000000000000001), 0.5);
EXPECT_EQ(ToFloat(0xFFFFFFFFFFFFFFFF), 0.9999999404f);
}
-TEST(DistributionImplTest, U64ToFloat_Positive_Zero_Test) {
+TEST(GenerateRealTest, U64ToFloat_Positive_Zero_Test) {
auto ToFloat = [](uint64_t a) {
- return RandU64ToFloat<PositiveValueT, true>(a);
+ return GenerateRealFromBits<float, GeneratePositiveTag, true>(a);
};
EXPECT_EQ(ToFloat(0x0000000000000000), 0.0);
EXPECT_EQ(ToFloat(0x0000000000000001), 5.421010862e-20f);
EXPECT_EQ(ToFloat(0x8000000000000000), 0.5);
+ EXPECT_EQ(ToFloat(0x8000000000000001), 0.5);
EXPECT_EQ(ToFloat(0xFFFFFFFFFFFFFFFF), 0.9999999404f);
}
-TEST(DistributionImplTest, U64ToFloat_Negative_NoZero_Test) {
+TEST(GenerateRealTest, U64ToFloat_Negative_NoZero_Test) {
auto ToFloat = [](uint64_t a) {
- return RandU64ToFloat<NegativeValueT, false>(a);
+ return GenerateRealFromBits<float, GenerateNegativeTag, false>(a);
};
EXPECT_EQ(ToFloat(0x0000000000000000), -2.710505431e-20f);
EXPECT_EQ(ToFloat(0x0000000000000001), -5.421010862e-20f);
EXPECT_EQ(ToFloat(0x8000000000000000), -0.5);
+ EXPECT_EQ(ToFloat(0x8000000000000001), -0.5);
EXPECT_EQ(ToFloat(0xFFFFFFFFFFFFFFFF), -0.9999999404f);
}
-TEST(DistributionImplTest, U64ToFloat_Signed_NoZero_Test) {
+TEST(GenerateRealTest, U64ToFloat_Negative_Zero_Test) {
auto ToFloat = [](uint64_t a) {
- return RandU64ToFloat<SignedValueT, false>(a);
+ return GenerateRealFromBits<float, GenerateNegativeTag, true>(a);
+ };
+ EXPECT_EQ(ToFloat(0x0000000000000000), 0.0);
+ EXPECT_EQ(ToFloat(0x0000000000000001), -5.421010862e-20f);
+ EXPECT_EQ(ToFloat(0x8000000000000000), -0.5);
+ EXPECT_EQ(ToFloat(0x8000000000000001), -0.5);
+ EXPECT_EQ(ToFloat(0xFFFFFFFFFFFFFFFF), -0.9999999404f);
+}
+
+TEST(GenerateRealTest, U64ToFloat_Signed_NoZero_Test) {
+ auto ToFloat = [](uint64_t a) {
+ return GenerateRealFromBits<float, GenerateSignedTag, false>(a);
};
EXPECT_EQ(ToFloat(0x0000000000000000), 5.421010862e-20f);
EXPECT_EQ(ToFloat(0x0000000000000001), 1.084202172e-19f);
@@ -72,9 +89,9 @@ TEST(DistributionImplTest, U64ToFloat_Signed_NoZero_Test) {
EXPECT_EQ(ToFloat(0xFFFFFFFFFFFFFFFF), -0.9999999404f);
}
-TEST(DistributionImplTest, U64ToFloat_Signed_Zero_Test) {
+TEST(GenerateRealTest, U64ToFloat_Signed_Zero_Test) {
auto ToFloat = [](uint64_t a) {
- return RandU64ToFloat<SignedValueT, true>(a);
+ return GenerateRealFromBits<float, GenerateSignedTag, true>(a);
};
EXPECT_EQ(ToFloat(0x0000000000000000), 0);
EXPECT_EQ(ToFloat(0x0000000000000001), 1.084202172e-19f);
@@ -84,9 +101,9 @@ TEST(DistributionImplTest, U64ToFloat_Signed_Zero_Test) {
EXPECT_EQ(ToFloat(0xFFFFFFFFFFFFFFFF), -0.9999999404f);
}
-TEST(DistributionImplTest, U64ToFloat_Signed_Bias_Test) {
+TEST(GenerateRealTest, U64ToFloat_Signed_Bias_Test) {
auto ToFloat = [](uint64_t a) {
- return RandU64ToFloat<SignedValueT, true, 1>(a);
+ return GenerateRealFromBits<float, GenerateSignedTag, true>(a, 1);
};
EXPECT_EQ(ToFloat(0x0000000000000000), 0);
EXPECT_EQ(ToFloat(0x0000000000000001), 2 * 1.084202172e-19f);
@@ -96,9 +113,9 @@ TEST(DistributionImplTest, U64ToFloat_Signed_Bias_Test) {
EXPECT_EQ(ToFloat(0xFFFFFFFFFFFFFFFF), 2 * -0.9999999404f);
}
-TEST(DistributionImplTest, U64ToFloatTest) {
+TEST(GenerateRealTest, U64ToFloatTest) {
auto ToFloat = [](uint64_t a) -> float {
- return RandU64ToFloat<PositiveValueT, true>(a);
+ return GenerateRealFromBits<float, GeneratePositiveTag, true>(a);
};
EXPECT_EQ(ToFloat(0x0000000000000000), 0.0f);
@@ -150,44 +167,60 @@ TEST(DistributionImplTest, U64ToFloatTest) {
}
}
-TEST(DistributionImplTest, U64ToDouble_Positive_NoZero_Test) {
+TEST(GenerateRealTest, U64ToDouble_Positive_NoZero_Test) {
auto ToDouble = [](uint64_t a) {
- return RandU64ToDouble<PositiveValueT, false>(a);
+ return GenerateRealFromBits<double, GeneratePositiveTag, false>(a);
};
EXPECT_EQ(ToDouble(0x0000000000000000), 2.710505431213761085e-20);
EXPECT_EQ(ToDouble(0x0000000000000001), 5.42101086242752217004e-20);
EXPECT_EQ(ToDouble(0x0000000000000002), 1.084202172485504434e-19);
EXPECT_EQ(ToDouble(0x8000000000000000), 0.5);
+ EXPECT_EQ(ToDouble(0x8000000000000001), 0.5);
EXPECT_EQ(ToDouble(0xFFFFFFFFFFFFFFFF), 0.999999999999999888978);
}
-TEST(DistributionImplTest, U64ToDouble_Positive_Zero_Test) {
+TEST(GenerateRealTest, U64ToDouble_Positive_Zero_Test) {
auto ToDouble = [](uint64_t a) {
- return RandU64ToDouble<PositiveValueT, true>(a);
+ return GenerateRealFromBits<double, GeneratePositiveTag, true>(a);
};
EXPECT_EQ(ToDouble(0x0000000000000000), 0.0);
EXPECT_EQ(ToDouble(0x0000000000000001), 5.42101086242752217004e-20);
EXPECT_EQ(ToDouble(0x8000000000000000), 0.5);
+ EXPECT_EQ(ToDouble(0x8000000000000001), 0.5);
EXPECT_EQ(ToDouble(0xFFFFFFFFFFFFFFFF), 0.999999999999999888978);
}
-TEST(DistributionImplTest, U64ToDouble_Negative_NoZero_Test) {
+TEST(GenerateRealTest, U64ToDouble_Negative_NoZero_Test) {
auto ToDouble = [](uint64_t a) {
- return RandU64ToDouble<NegativeValueT, false>(a);
+ return GenerateRealFromBits<double, GenerateNegativeTag, false>(a);
};
EXPECT_EQ(ToDouble(0x0000000000000000), -2.710505431213761085e-20);
EXPECT_EQ(ToDouble(0x0000000000000001), -5.42101086242752217004e-20);
EXPECT_EQ(ToDouble(0x0000000000000002), -1.084202172485504434e-19);
EXPECT_EQ(ToDouble(0x8000000000000000), -0.5);
+ EXPECT_EQ(ToDouble(0x8000000000000001), -0.5);
+ EXPECT_EQ(ToDouble(0xFFFFFFFFFFFFFFFF), -0.999999999999999888978);
+}
+
+TEST(GenerateRealTest, U64ToDouble_Negative_Zero_Test) {
+ auto ToDouble = [](uint64_t a) {
+ return GenerateRealFromBits<double, GenerateNegativeTag, true>(a);
+ };
+
+ EXPECT_EQ(ToDouble(0x0000000000000000), 0.0);
+ EXPECT_EQ(ToDouble(0x0000000000000001), -5.42101086242752217004e-20);
+ EXPECT_EQ(ToDouble(0x0000000000000002), -1.084202172485504434e-19);
+ EXPECT_EQ(ToDouble(0x8000000000000000), -0.5);
+ EXPECT_EQ(ToDouble(0x8000000000000001), -0.5);
EXPECT_EQ(ToDouble(0xFFFFFFFFFFFFFFFF), -0.999999999999999888978);
}
-TEST(DistributionImplTest, U64ToDouble_Signed_NoZero_Test) {
+TEST(GenerateRealTest, U64ToDouble_Signed_NoZero_Test) {
auto ToDouble = [](uint64_t a) {
- return RandU64ToDouble<SignedValueT, false>(a);
+ return GenerateRealFromBits<double, GenerateSignedTag, false>(a);
};
EXPECT_EQ(ToDouble(0x0000000000000000), 5.42101086242752217004e-20);
@@ -198,9 +231,9 @@ TEST(DistributionImplTest, U64ToDouble_Signed_NoZero_Test) {
EXPECT_EQ(ToDouble(0xFFFFFFFFFFFFFFFF), -0.999999999999999888978);
}
-TEST(DistributionImplTest, U64ToDouble_Signed_Zero_Test) {
+TEST(GenerateRealTest, U64ToDouble_Signed_Zero_Test) {
auto ToDouble = [](uint64_t a) {
- return RandU64ToDouble<SignedValueT, true>(a);
+ return GenerateRealFromBits<double, GenerateSignedTag, true>(a);
};
EXPECT_EQ(ToDouble(0x0000000000000000), 0);
EXPECT_EQ(ToDouble(0x0000000000000001), 1.084202172485504434e-19);
@@ -210,9 +243,9 @@ TEST(DistributionImplTest, U64ToDouble_Signed_Zero_Test) {
EXPECT_EQ(ToDouble(0xFFFFFFFFFFFFFFFF), -0.999999999999999888978);
}
-TEST(DistributionImplTest, U64ToDouble_Signed_Bias_Test) {
+TEST(GenerateRealTest, U64ToDouble_GenerateSignedTag_Bias_Test) {
auto ToDouble = [](uint64_t a) {
- return RandU64ToDouble<SignedValueT, true, -1>(a);
+ return GenerateRealFromBits<double, GenerateSignedTag, true>(a, -1);
};
EXPECT_EQ(ToDouble(0x0000000000000000), 0);
EXPECT_EQ(ToDouble(0x0000000000000001), 1.084202172485504434e-19 / 2);
@@ -222,9 +255,9 @@ TEST(DistributionImplTest, U64ToDouble_Signed_Bias_Test) {
EXPECT_EQ(ToDouble(0xFFFFFFFFFFFFFFFF), -0.999999999999999888978 / 2);
}
-TEST(DistributionImplTest, U64ToDoubleTest) {
+TEST(GenerateRealTest, U64ToDoubleTest) {
auto ToDouble = [](uint64_t a) {
- return RandU64ToDouble<PositiveValueT, true>(a);
+ return GenerateRealFromBits<double, GeneratePositiveTag, true>(a);
};
EXPECT_EQ(ToDouble(0x0000000000000000), 0.0);
@@ -296,9 +329,9 @@ TEST(DistributionImplTest, U64ToDoubleTest) {
}
}
-TEST(DistributionImplTest, U64ToDoubleSignedTest) {
+TEST(GenerateRealTest, U64ToDoubleSignedTest) {
auto ToDouble = [](uint64_t a) {
- return RandU64ToDouble<SignedValueT, false>(a);
+ return GenerateRealFromBits<double, GenerateSignedTag, false>(a);
};
EXPECT_EQ(ToDouble(0x0000000000000000), 5.42101086242752217004e-20);
@@ -379,10 +412,10 @@ TEST(DistributionImplTest, U64ToDoubleSignedTest) {
}
}
-TEST(DistributionImplTest, ExhaustiveFloat) {
+TEST(GenerateRealTest, ExhaustiveFloat) {
using absl::base_internal::CountLeadingZeros64;
auto ToFloat = [](uint64_t a) {
- return RandU64ToFloat<PositiveValueT, true>(a);
+ return GenerateRealFromBits<float, GeneratePositiveTag, true>(a);
};
// Rely on RandU64ToFloat generating values from greatest to least when
diff --git a/absl/random/log_uniform_int_distribution.h b/absl/random/log_uniform_int_distribution.h
index ac43416e..956a6907 100644
--- a/absl/random/log_uniform_int_distribution.h
+++ b/absl/random/log_uniform_int_distribution.h
@@ -23,8 +23,8 @@
#include <ostream>
#include <type_traits>
-#include "absl/random/internal/distribution_impl.h"
#include "absl/random/internal/fastmath.h"
+#include "absl/random/internal/generate_real.h"
#include "absl/random/internal/iostream_state_saver.h"
#include "absl/random/internal/traits.h"
#include "absl/random/uniform_int_distribution.h"
diff --git a/absl/random/poisson_distribution.h b/absl/random/poisson_distribution.h
index 7750b1c9..23a953ff 100644
--- a/absl/random/poisson_distribution.h
+++ b/absl/random/poisson_distribution.h
@@ -22,9 +22,9 @@
#include <ostream>
#include <type_traits>
-#include "absl/random/internal/distribution_impl.h"
#include "absl/random/internal/fast_uniform_bits.h"
#include "absl/random/internal/fastmath.h"
+#include "absl/random/internal/generate_real.h"
#include "absl/random/internal/iostream_state_saver.h"
namespace absl {
@@ -164,9 +164,9 @@ typename poisson_distribution<IntType>::result_type
poisson_distribution<IntType>::operator()(
URBG& g, // NOLINT(runtime/references)
const param_type& p) {
- using random_internal::PositiveValueT;
- using random_internal::RandU64ToDouble;
- using random_internal::SignedValueT;
+ using random_internal::GeneratePositiveTag;
+ using random_internal::GenerateRealFromBits;
+ using random_internal::GenerateSignedTag;
if (p.split_ != 0) {
// Use Knuth's algorithm with range splitting to avoid floating-point
@@ -186,7 +186,8 @@ poisson_distribution<IntType>::operator()(
for (int split = p.split_; split > 0; --split) {
double r = 1.0;
do {
- r *= RandU64ToDouble<PositiveValueT, true>(fast_u64_(g));
+ r *= GenerateRealFromBits<double, GeneratePositiveTag, true>(
+ fast_u64_(g)); // U(-1, 0)
++n;
} while (r > p.emu_);
--n;
@@ -205,10 +206,11 @@ poisson_distribution<IntType>::operator()(
// and k = max(f).
const double a = p.mean_ + 0.5;
for (;;) {
- const double u =
- RandU64ToDouble<PositiveValueT, false>(fast_u64_(g)); // (0, 1)
- const double v =
- RandU64ToDouble<SignedValueT, false>(fast_u64_(g)); // (-1, 1)
+ const double u = GenerateRealFromBits<double, GeneratePositiveTag, false>(
+ fast_u64_(g)); // U(0, 1)
+ const double v = GenerateRealFromBits<double, GenerateSignedTag, false>(
+ fast_u64_(g)); // U(-1, 1)
+
const double x = std::floor(p.s_ * v / u + a);
if (x < 0) continue; // f(negative) = 0
const double rhs = x * p.lmu_;
diff --git a/absl/random/uniform_int_distribution.h b/absl/random/uniform_int_distribution.h
index 02aa3765..dc8ba8c1 100644
--- a/absl/random/uniform_int_distribution.h
+++ b/absl/random/uniform_int_distribution.h
@@ -34,7 +34,6 @@
#include <type_traits>
#include "absl/base/optimization.h"
-#include "absl/random/internal/distribution_impl.h"
#include "absl/random/internal/fast_uniform_bits.h"
#include "absl/random/internal/iostream_state_saver.h"
#include "absl/random/internal/traits.h"
diff --git a/absl/random/uniform_real_distribution.h b/absl/random/uniform_real_distribution.h
index 336abb39..bf2ed2c5 100644
--- a/absl/random/uniform_real_distribution.h
+++ b/absl/random/uniform_real_distribution.h
@@ -39,8 +39,9 @@
#include <limits>
#include <type_traits>
-#include "absl/random/internal/distribution_impl.h"
+#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 {
@@ -76,6 +77,7 @@ class uniform_real_distribution {
// 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_; }
@@ -151,10 +153,15 @@ 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::PositiveValueT;
+ 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 = random_internal::RandU64ToReal<
- result_type>::template Value<PositiveValueT, true>(fast_u64_(gen));
+ 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;