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author | 2019-06-21 13:11:42 -0700 | |
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committer | 2019-06-21 16:18:10 -0400 | |
commit | e9324d926a9189e222741fce6e676f0944661a72 (patch) | |
tree | a08568a709940c376454da34c9d8aac021378e5f /absl/random/internal/fastmath_test.cc | |
parent | 43ef2148c0936ebf7cb4be6b19927a9d9d145b8f (diff) |
Export of internal Abseil changes.
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7a6ff16a85beb730c172d5d25cf1b5e1be885c56 by Laramie Leavitt <lar@google.com>:
Internal change.
PiperOrigin-RevId: 254454546
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ff8f9bafaefc26d451f576ea4a06d150aed63f6f by Andy Soffer <asoffer@google.com>:
Internal changes
PiperOrigin-RevId: 254451562
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deefc5b651b479ce36f0b4ef203e119c0c8936f2 by CJ Johnson <johnsoncj@google.com>:
Account for subtracting unsigned values from the size of InlinedVector
PiperOrigin-RevId: 254450625
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3c677316a27bcadc17e41957c809ca472d5fef14 by Andy Soffer <asoffer@google.com>:
Add C++17's std::make_from_tuple to absl/utility/utility.h
PiperOrigin-RevId: 254411573
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4ee3536a918830eeec402a28fc31a62c7c90b940 by CJ Johnson <johnsoncj@google.com>:
Adds benchmark for the rest of the InlinedVector public API
PiperOrigin-RevId: 254408378
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e5a21a00700ee83498ff1efbf649169756463ee4 by CJ Johnson <johnsoncj@google.com>:
Updates the definition of InlinedVector::shrink_to_fit() to be exception safe and adds exception safety tests for it.
PiperOrigin-RevId: 254401387
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2ea82e72b86d82d78b4e4712a63a55981b53c64b by Laramie Leavitt <lar@google.com>:
Use absl::InsecureBitGen in place of std::mt19937
in tests absl/random/...distribution_test.cc
PiperOrigin-RevId: 254289444
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fa099e02c413a7ffda732415e8105cad26a90337 by Andy Soffer <asoffer@google.com>:
Internal changes
PiperOrigin-RevId: 254286334
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ce34b7f36933b30cfa35b9c9a5697a792b5666e4 by Andy Soffer <asoffer@google.com>:
Internal changes
PiperOrigin-RevId: 254273059
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6f9c473da7c2090c2e85a37c5f00622e8a912a89 by Jorg Brown <jorg@google.com>:
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
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8bd3c186bf2fc0c55d8a2dd6f28a5327502c9fba by Andy Soffer <asoffer@google.com>:
Adding short-hand IntervalClosed for IntervalClosedClosed and IntervalOpen for
IntervalOpenOpen.
PiperOrigin-RevId: 254252419
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ea957f99b6a04fccd42aa05605605f3b44b1ecfd by Abseil Team <absl-team@google.com>:
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
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89ab385cd26b34d64130bce856253aaba96d2345 by Andy Soffer <asoffer@google.com>:
Internal changes
PiperOrigin-RevId: 254242321
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cffc793d93eca6d6bdf7de733847b6ab4a255ae9 by CJ Johnson <johnsoncj@google.com>:
Adds benchmark for InlinedVector::reserve(size_type)
PiperOrigin-RevId: 254199226
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c90c7a9fa3c8f0c9d5114036979548b055ea2f2a by Gennadiy Rozental <rogeeff@google.com>:
Import of CCTZ from GitHub.
PiperOrigin-RevId: 254072387
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c4c388beae016c9570ab54ffa1d52660e4a85b7b by Laramie Leavitt <lar@google.com>:
Internal cleanup.
PiperOrigin-RevId: 254062381
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d3c992e221cc74e5372d0c8fa410170b6a43c062 by Tom Manshreck <shreck@google.com>:
Update distributions.h to Abseil standards
PiperOrigin-RevId: 254054946
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d15ad0035c34ef11b14fadc5a4a2d3ec415f5518 by CJ Johnson <johnsoncj@google.com>:
Removes functions with only one caller from the implementation details of InlinedVector by manually inlining the definitions
PiperOrigin-RevId: 254005427
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2f37e807efc3a8ef1f4b539bdd379917d4151520 by Andy Soffer <asoffer@google.com>:
Initial release of Abseil Random
PiperOrigin-RevId: 253999861
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24ed1694b6430791d781ed533a8f8ccf6cac5856 by CJ Johnson <johnsoncj@google.com>:
Updates the definition of InlinedVector::assign(...)/InlinedVector::operator=(...) to new, exception-safe implementations with exception safety tests to boot
PiperOrigin-RevId: 253993691
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5613d95f5a7e34a535cfaeadce801441e990843e by CJ Johnson <johnsoncj@google.com>:
Adds benchmarks for InlinedVector::shrink_to_fit()
PiperOrigin-RevId: 253989647
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2a96ddfdac40bbb8cb6a7f1aeab90917067c6e63 by Abseil Team <absl-team@google.com>:
Initial release of Abseil Random
PiperOrigin-RevId: 253927497
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bf1aff8fc9ffa921ad74643e9525ecf25b0d8dc1 by Andy Soffer <asoffer@google.com>:
Initial release of Abseil Random
PiperOrigin-RevId: 253920512
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bfc03f4a3dcda3cf3a4b84bdb84cda24e3394f41 by Laramie Leavitt <lar@google.com>:
Internal change.
PiperOrigin-RevId: 253886486
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05036cfcc078ca7c5f581a00dfb0daed568cbb69 by Eric Fiselier <ericwf@google.com>:
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
Diffstat (limited to 'absl/random/internal/fastmath_test.cc')
-rw-r--r-- | absl/random/internal/fastmath_test.cc | 110 |
1 files changed, 110 insertions, 0 deletions
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<uint64_t>(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<int>(std::log2(~kZero))); + + for (int i = 0; i < 64; i++) { + const uint64_t i_pow_2 = static_cast<uint64_t>(1) << i; + EXPECT_EQ(i, IntLog2Floor(i_pow_2)); + EXPECT_EQ(i, static_cast<int>(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<int>(std::log2(~kZero))); + + for (int i = 0; i < 64; i++) { + const uint64_t i_pow_2 = static_cast<uint64_t>(1) << i; + EXPECT_EQ(i, IntLog2Ceil(i_pow_2)); +#ifndef ABSL_RANDOM_INACCURATE_LOG2 + EXPECT_EQ(i, static_cast<int>(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<double>(i); + EXPECT_NEAR(StirlingLogFactorial(d), std::lgamma(d + 1), 3e-5); + } +} + +} // namespace |