From e9324d926a9189e222741fce6e676f0944661a72 Mon Sep 17 00:00:00 2001 From: Abseil Team Date: Fri, 21 Jun 2019 13:11:42 -0700 Subject: Export of internal Abseil changes. -- 7a6ff16a85beb730c172d5d25cf1b5e1be885c56 by Laramie Leavitt : Internal change. PiperOrigin-RevId: 254454546 -- ff8f9bafaefc26d451f576ea4a06d150aed63f6f by Andy Soffer : Internal changes PiperOrigin-RevId: 254451562 -- deefc5b651b479ce36f0b4ef203e119c0c8936f2 by CJ Johnson : Account for subtracting unsigned values from the size of InlinedVector PiperOrigin-RevId: 254450625 -- 3c677316a27bcadc17e41957c809ca472d5fef14 by Andy Soffer : Add C++17's std::make_from_tuple to absl/utility/utility.h PiperOrigin-RevId: 254411573 -- 4ee3536a918830eeec402a28fc31a62c7c90b940 by CJ Johnson : Adds benchmark for the rest of the InlinedVector public API PiperOrigin-RevId: 254408378 -- e5a21a00700ee83498ff1efbf649169756463ee4 by CJ Johnson : Updates the definition of InlinedVector::shrink_to_fit() to be exception safe and adds exception safety tests for it. PiperOrigin-RevId: 254401387 -- 2ea82e72b86d82d78b4e4712a63a55981b53c64b by Laramie Leavitt : Use absl::InsecureBitGen in place of std::mt19937 in tests absl/random/...distribution_test.cc PiperOrigin-RevId: 254289444 -- fa099e02c413a7ffda732415e8105cad26a90337 by Andy Soffer : Internal changes PiperOrigin-RevId: 254286334 -- ce34b7f36933b30cfa35b9c9a5697a792b5666e4 by Andy Soffer : Internal changes PiperOrigin-RevId: 254273059 -- 6f9c473da7c2090c2e85a37c5f00622e8a912a89 by Jorg Brown : Change absl::container_internal::CompressedTuple to instantiate its internal Storage class with the name of the type it's holding, rather than the name of the Tuple. This is not an externally-visible change, other than less compiler memory is used and less debug information is generated. PiperOrigin-RevId: 254269285 -- 8bd3c186bf2fc0c55d8a2dd6f28a5327502c9fba by Andy Soffer : Adding short-hand IntervalClosed for IntervalClosedClosed and IntervalOpen for IntervalOpenOpen. PiperOrigin-RevId: 254252419 -- ea957f99b6a04fccd42aa05605605f3b44b1ecfd by Abseil Team : Do not directly use __SIZEOF_INT128__. In order to avoid linker errors when building with clang-cl (__fixunsdfti, __udivti3 and __fixunssfti are undefined), this CL uses ABSL_HAVE_INTRINSIC_INT128 which is not defined for clang-cl. PiperOrigin-RevId: 254250739 -- 89ab385cd26b34d64130bce856253aaba96d2345 by Andy Soffer : Internal changes PiperOrigin-RevId: 254242321 -- cffc793d93eca6d6bdf7de733847b6ab4a255ae9 by CJ Johnson : Adds benchmark for InlinedVector::reserve(size_type) PiperOrigin-RevId: 254199226 -- c90c7a9fa3c8f0c9d5114036979548b055ea2f2a by Gennadiy Rozental : Import of CCTZ from GitHub. PiperOrigin-RevId: 254072387 -- c4c388beae016c9570ab54ffa1d52660e4a85b7b by Laramie Leavitt : Internal cleanup. PiperOrigin-RevId: 254062381 -- d3c992e221cc74e5372d0c8fa410170b6a43c062 by Tom Manshreck : Update distributions.h to Abseil standards PiperOrigin-RevId: 254054946 -- d15ad0035c34ef11b14fadc5a4a2d3ec415f5518 by CJ Johnson : Removes functions with only one caller from the implementation details of InlinedVector by manually inlining the definitions PiperOrigin-RevId: 254005427 -- 2f37e807efc3a8ef1f4b539bdd379917d4151520 by Andy Soffer : Initial release of Abseil Random PiperOrigin-RevId: 253999861 -- 24ed1694b6430791d781ed533a8f8ccf6cac5856 by CJ Johnson : Updates the definition of InlinedVector::assign(...)/InlinedVector::operator=(...) to new, exception-safe implementations with exception safety tests to boot PiperOrigin-RevId: 253993691 -- 5613d95f5a7e34a535cfaeadce801441e990843e by CJ Johnson : Adds benchmarks for InlinedVector::shrink_to_fit() PiperOrigin-RevId: 253989647 -- 2a96ddfdac40bbb8cb6a7f1aeab90917067c6e63 by Abseil Team : Initial release of Abseil Random PiperOrigin-RevId: 253927497 -- bf1aff8fc9ffa921ad74643e9525ecf25b0d8dc1 by Andy Soffer : Initial release of Abseil Random PiperOrigin-RevId: 253920512 -- bfc03f4a3dcda3cf3a4b84bdb84cda24e3394f41 by Laramie Leavitt : Internal change. PiperOrigin-RevId: 253886486 -- 05036cfcc078ca7c5f581a00dfb0daed568cbb69 by Eric Fiselier : Don't include `winsock2.h` because it drags in `windows.h` and friends, and they define awful macros like OPAQUE, ERROR, and more. This has the potential to break abseil users. Instead we only forward declare `timeval` and require Windows users include `winsock2.h` themselves. This is both inconsistent and poor QoI, but so including 'windows.h' is bad too. PiperOrigin-RevId: 253852615 GitOrigin-RevId: 7a6ff16a85beb730c172d5d25cf1b5e1be885c56 Change-Id: Icd6aff87da26f29ec8915da856f051129987cef6 --- absl/random/internal/fastmath_test.cc | 110 ++++++++++++++++++++++++++++++++++ 1 file changed, 110 insertions(+) create mode 100644 absl/random/internal/fastmath_test.cc (limited to 'absl/random/internal/fastmath_test.cc') diff --git a/absl/random/internal/fastmath_test.cc b/absl/random/internal/fastmath_test.cc new file mode 100644 index 00000000..65859c25 --- /dev/null +++ b/absl/random/internal/fastmath_test.cc @@ -0,0 +1,110 @@ +// 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. + +#include "absl/random/internal/fastmath.h" + +#include "gtest/gtest.h" + +#if defined(__native_client__) || defined(__EMSCRIPTEN__) +// NACL has a less accurate implementation of std::log2 than most of +// the other platforms. For some values which should have integral results, +// sometimes NACL returns slightly larger values. +// +// The MUSL libc used by emscripten also has a similar bug. +#define ABSL_RANDOM_INACCURATE_LOG2 +#endif + +namespace { + +TEST(DistributionImplTest, LeadingSetBit) { + using absl::random_internal::LeadingSetBit; + constexpr uint64_t kZero = 0; + EXPECT_EQ(0, LeadingSetBit(kZero)); + EXPECT_EQ(64, LeadingSetBit(~kZero)); + + for (int index = 0; index < 64; index++) { + uint64_t x = static_cast(1) << index; + EXPECT_EQ(index + 1, LeadingSetBit(x)) << index; + EXPECT_EQ(index + 1, LeadingSetBit(x + x - 1)) << index; + } +} + +TEST(FastMathTest, IntLog2FloorTest) { + using absl::random_internal::IntLog2Floor; + constexpr uint64_t kZero = 0; + EXPECT_EQ(0, IntLog2Floor(0)); // boundary. return 0. + EXPECT_EQ(0, IntLog2Floor(1)); + EXPECT_EQ(1, IntLog2Floor(2)); + EXPECT_EQ(63, IntLog2Floor(~kZero)); + + // A boundary case: Converting 0xffffffffffffffff requires > 53 + // bits of precision, so the conversion to double rounds up, + // and the result of std::log2(x) > IntLog2Floor(x). + EXPECT_LT(IntLog2Floor(~kZero), static_cast(std::log2(~kZero))); + + for (int i = 0; i < 64; i++) { + const uint64_t i_pow_2 = static_cast(1) << i; + EXPECT_EQ(i, IntLog2Floor(i_pow_2)); + EXPECT_EQ(i, static_cast(std::log2(i_pow_2))); + + uint64_t y = i_pow_2; + for (int j = i - 1; j > 0; --j) { + y = y | (i_pow_2 >> j); + EXPECT_EQ(i, IntLog2Floor(y)); + } + } +} + +TEST(FastMathTest, IntLog2CeilTest) { + using absl::random_internal::IntLog2Ceil; + constexpr uint64_t kZero = 0; + EXPECT_EQ(0, IntLog2Ceil(0)); // boundary. return 0. + EXPECT_EQ(0, IntLog2Ceil(1)); + EXPECT_EQ(1, IntLog2Ceil(2)); + EXPECT_EQ(64, IntLog2Ceil(~kZero)); + + // A boundary case: Converting 0xffffffffffffffff requires > 53 + // bits of precision, so the conversion to double rounds up, + // and the result of std::log2(x) > IntLog2Floor(x). + EXPECT_LE(IntLog2Ceil(~kZero), static_cast(std::log2(~kZero))); + + for (int i = 0; i < 64; i++) { + const uint64_t i_pow_2 = static_cast(1) << i; + EXPECT_EQ(i, IntLog2Ceil(i_pow_2)); +#ifndef ABSL_RANDOM_INACCURATE_LOG2 + EXPECT_EQ(i, static_cast(std::ceil(std::log2(i_pow_2)))); +#endif + + uint64_t y = i_pow_2; + for (int j = i - 1; j > 0; --j) { + y = y | (i_pow_2 >> j); + EXPECT_EQ(i + 1, IntLog2Ceil(y)); + } + } +} + +TEST(FastMathTest, StirlingLogFactorial) { + using absl::random_internal::StirlingLogFactorial; + + EXPECT_NEAR(StirlingLogFactorial(1.0), 0, 1e-3); + EXPECT_NEAR(StirlingLogFactorial(1.50), 0.284683, 1e-3); + EXPECT_NEAR(StirlingLogFactorial(2.0), 0.69314718056, 1e-4); + + for (int i = 2; i < 50; i++) { + double d = static_cast(i); + EXPECT_NEAR(StirlingLogFactorial(d), std::lgamma(d + 1), 3e-5); + } +} + +} // namespace -- cgit v1.2.3