From 5aa5d282eac56a21e74611c1cdbaa97bb5db2dca Mon Sep 17 00:00:00 2001 From: Vincent Ambo Date: Tue, 8 Feb 2022 02:05:36 +0300 Subject: chore(3p/abseil_cpp): unvendor abseil_cpp we weren't actually using these sources anymore, okay? Change-Id: If701571d9716de308d3512e1eb22c35db0877a66 Reviewed-on: https://cl.tvl.fyi/c/depot/+/5248 Tested-by: BuildkiteCI Reviewed-by: grfn Autosubmit: tazjin --- .../absl/random/internal/generate_real_test.cc | 497 --------------------- 1 file changed, 497 deletions(-) delete mode 100644 third_party/abseil_cpp/absl/random/internal/generate_real_test.cc (limited to 'third_party/abseil_cpp/absl/random/internal/generate_real_test.cc') diff --git a/third_party/abseil_cpp/absl/random/internal/generate_real_test.cc b/third_party/abseil_cpp/absl/random/internal/generate_real_test.cc deleted file mode 100644 index 4bdc453483e4..000000000000 --- a/third_party/abseil_cpp/absl/random/internal/generate_real_test.cc +++ /dev/null @@ -1,497 +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. - -#include "absl/random/internal/generate_real.h" - -#include -#include -#include -#include - -#include "gtest/gtest.h" -#include "absl/base/internal/bits.h" -#include "absl/flags/flag.h" - -ABSL_FLAG(int64_t, absl_random_test_trials, 50000, - "Number of trials for the probability tests."); - -using absl::random_internal::GenerateNegativeTag; -using absl::random_internal::GeneratePositiveTag; -using absl::random_internal::GenerateRealFromBits; -using absl::random_internal::GenerateSignedTag; - -namespace { - -TEST(GenerateRealTest, U64ToFloat_Positive_NoZero_Test) { - auto ToFloat = [](uint64_t a) { - return GenerateRealFromBits(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(GenerateRealTest, U64ToFloat_Positive_Zero_Test) { - auto ToFloat = [](uint64_t a) { - return GenerateRealFromBits(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_Negative_NoZero_Test) { - auto ToFloat = [](uint64_t a) { - return GenerateRealFromBits(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(GenerateRealTest, U64ToFloat_Negative_Zero_Test) { - auto ToFloat = [](uint64_t a) { - return GenerateRealFromBits(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(a); - }; - EXPECT_EQ(ToFloat(0x0000000000000000), 5.421010862e-20f); - EXPECT_EQ(ToFloat(0x0000000000000001), 1.084202172e-19f); - EXPECT_EQ(ToFloat(0x7FFFFFFFFFFFFFFF), 0.9999999404f); - EXPECT_EQ(ToFloat(0x8000000000000000), -5.421010862e-20f); - EXPECT_EQ(ToFloat(0x8000000000000001), -1.084202172e-19f); - EXPECT_EQ(ToFloat(0xFFFFFFFFFFFFFFFF), -0.9999999404f); -} - -TEST(GenerateRealTest, U64ToFloat_Signed_Zero_Test) { - auto ToFloat = [](uint64_t a) { - return GenerateRealFromBits(a); - }; - EXPECT_EQ(ToFloat(0x0000000000000000), 0); - EXPECT_EQ(ToFloat(0x0000000000000001), 1.084202172e-19f); - EXPECT_EQ(ToFloat(0x7FFFFFFFFFFFFFFF), 0.9999999404f); - EXPECT_EQ(ToFloat(0x8000000000000000), 0); - EXPECT_EQ(ToFloat(0x8000000000000001), -1.084202172e-19f); - EXPECT_EQ(ToFloat(0xFFFFFFFFFFFFFFFF), -0.9999999404f); -} - -TEST(GenerateRealTest, U64ToFloat_Signed_Bias_Test) { - auto ToFloat = [](uint64_t a) { - return GenerateRealFromBits(a, 1); - }; - EXPECT_EQ(ToFloat(0x0000000000000000), 0); - EXPECT_EQ(ToFloat(0x0000000000000001), 2 * 1.084202172e-19f); - EXPECT_EQ(ToFloat(0x7FFFFFFFFFFFFFFF), 2 * 0.9999999404f); - EXPECT_EQ(ToFloat(0x8000000000000000), 0); - EXPECT_EQ(ToFloat(0x8000000000000001), 2 * -1.084202172e-19f); - EXPECT_EQ(ToFloat(0xFFFFFFFFFFFFFFFF), 2 * -0.9999999404f); -} - -TEST(GenerateRealTest, U64ToFloatTest) { - auto ToFloat = [](uint64_t a) -> float { - return GenerateRealFromBits(a); - }; - - EXPECT_EQ(ToFloat(0x0000000000000000), 0.0f); - - EXPECT_EQ(ToFloat(0x8000000000000000), 0.5f); - EXPECT_EQ(ToFloat(0x8000000000000001), 0.5f); - EXPECT_EQ(ToFloat(0x800000FFFFFFFFFF), 0.5f); - EXPECT_EQ(ToFloat(0xFFFFFFFFFFFFFFFF), 0.9999999404f); - - EXPECT_GT(ToFloat(0x0000000000000001), 0.0f); - - EXPECT_NE(ToFloat(0x7FFFFF0000000000), ToFloat(0x7FFFFEFFFFFFFFFF)); - - EXPECT_LT(ToFloat(0xFFFFFFFFFFFFFFFF), 1.0f); - int32_t two_to_24 = 1 << 24; - EXPECT_EQ(static_cast(ToFloat(0xFFFFFFFFFFFFFFFF) * two_to_24), - two_to_24 - 1); - EXPECT_NE(static_cast(ToFloat(0xFFFFFFFFFFFFFFFF) * two_to_24 * 2), - two_to_24 * 2 - 1); - EXPECT_EQ(ToFloat(0xFFFFFFFFFFFFFFFF), ToFloat(0xFFFFFF0000000000)); - EXPECT_NE(ToFloat(0xFFFFFFFFFFFFFFFF), ToFloat(0xFFFFFEFFFFFFFFFF)); - EXPECT_EQ(ToFloat(0x7FFFFFFFFFFFFFFF), ToFloat(0x7FFFFF8000000000)); - EXPECT_NE(ToFloat(0x7FFFFFFFFFFFFFFF), ToFloat(0x7FFFFF7FFFFFFFFF)); - EXPECT_EQ(ToFloat(0x3FFFFFFFFFFFFFFF), ToFloat(0x3FFFFFC000000000)); - EXPECT_NE(ToFloat(0x3FFFFFFFFFFFFFFF), ToFloat(0x3FFFFFBFFFFFFFFF)); - - // For values where every bit counts, the values scale as multiples of the - // input. - for (int i = 0; i < 100; ++i) { - EXPECT_EQ(i * ToFloat(0x0000000000000001), ToFloat(i)); - } - - // For each i: value generated from (1 << i). - float exp_values[64]; - exp_values[63] = 0.5f; - for (int i = 62; i >= 0; --i) exp_values[i] = 0.5f * exp_values[i + 1]; - constexpr uint64_t one = 1; - for (int i = 0; i < 64; ++i) { - EXPECT_EQ(ToFloat(one << i), exp_values[i]); - for (int j = 1; j < FLT_MANT_DIG && i - j >= 0; ++j) { - EXPECT_NE(exp_values[i] + exp_values[i - j], exp_values[i]); - EXPECT_EQ(ToFloat((one << i) + (one << (i - j))), - exp_values[i] + exp_values[i - j]); - } - for (int j = FLT_MANT_DIG; i - j >= 0; ++j) { - EXPECT_EQ(exp_values[i] + exp_values[i - j], exp_values[i]); - EXPECT_EQ(ToFloat((one << i) + (one << (i - j))), exp_values[i]); - } - } -} - -TEST(GenerateRealTest, U64ToDouble_Positive_NoZero_Test) { - auto ToDouble = [](uint64_t a) { - return GenerateRealFromBits(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_Positive_Zero_Test) { - auto ToDouble = [](uint64_t a) { - return GenerateRealFromBits(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(GenerateRealTest, U64ToDouble_Negative_NoZero_Test) { - auto ToDouble = [](uint64_t a) { - return GenerateRealFromBits(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(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(GenerateRealTest, U64ToDouble_Signed_NoZero_Test) { - auto ToDouble = [](uint64_t a) { - return GenerateRealFromBits(a); - }; - - EXPECT_EQ(ToDouble(0x0000000000000000), 5.42101086242752217004e-20); - EXPECT_EQ(ToDouble(0x0000000000000001), 1.084202172485504434e-19); - EXPECT_EQ(ToDouble(0x7FFFFFFFFFFFFFFF), 0.999999999999999888978); - EXPECT_EQ(ToDouble(0x8000000000000000), -5.42101086242752217004e-20); - EXPECT_EQ(ToDouble(0x8000000000000001), -1.084202172485504434e-19); - EXPECT_EQ(ToDouble(0xFFFFFFFFFFFFFFFF), -0.999999999999999888978); -} - -TEST(GenerateRealTest, U64ToDouble_Signed_Zero_Test) { - auto ToDouble = [](uint64_t a) { - return GenerateRealFromBits(a); - }; - EXPECT_EQ(ToDouble(0x0000000000000000), 0); - EXPECT_EQ(ToDouble(0x0000000000000001), 1.084202172485504434e-19); - EXPECT_EQ(ToDouble(0x7FFFFFFFFFFFFFFF), 0.999999999999999888978); - EXPECT_EQ(ToDouble(0x8000000000000000), 0); - EXPECT_EQ(ToDouble(0x8000000000000001), -1.084202172485504434e-19); - EXPECT_EQ(ToDouble(0xFFFFFFFFFFFFFFFF), -0.999999999999999888978); -} - -TEST(GenerateRealTest, U64ToDouble_GenerateSignedTag_Bias_Test) { - auto ToDouble = [](uint64_t a) { - return GenerateRealFromBits(a, -1); - }; - EXPECT_EQ(ToDouble(0x0000000000000000), 0); - EXPECT_EQ(ToDouble(0x0000000000000001), 1.084202172485504434e-19 / 2); - EXPECT_EQ(ToDouble(0x7FFFFFFFFFFFFFFF), 0.999999999999999888978 / 2); - EXPECT_EQ(ToDouble(0x8000000000000000), 0); - EXPECT_EQ(ToDouble(0x8000000000000001), -1.084202172485504434e-19 / 2); - EXPECT_EQ(ToDouble(0xFFFFFFFFFFFFFFFF), -0.999999999999999888978 / 2); -} - -TEST(GenerateRealTest, U64ToDoubleTest) { - auto ToDouble = [](uint64_t a) { - return GenerateRealFromBits(a); - }; - - EXPECT_EQ(ToDouble(0x0000000000000000), 0.0); - EXPECT_EQ(ToDouble(0x0000000000000000), 0.0); - - EXPECT_EQ(ToDouble(0x0000000000000001), 5.42101086242752217004e-20); - EXPECT_EQ(ToDouble(0x7fffffffffffffef), 0.499999999999999944489); - EXPECT_EQ(ToDouble(0x8000000000000000), 0.5); - - // For values > 0.5, RandU64ToDouble discards up to 11 bits. (64-53). - EXPECT_EQ(ToDouble(0x8000000000000001), 0.5); - EXPECT_EQ(ToDouble(0x80000000000007FF), 0.5); - EXPECT_EQ(ToDouble(0xFFFFFFFFFFFFFFFF), 0.999999999999999888978); - EXPECT_NE(ToDouble(0x7FFFFFFFFFFFF800), ToDouble(0x7FFFFFFFFFFFF7FF)); - - EXPECT_LT(ToDouble(0xFFFFFFFFFFFFFFFF), 1.0); - EXPECT_EQ(ToDouble(0xFFFFFFFFFFFFFFFF), ToDouble(0xFFFFFFFFFFFFF800)); - EXPECT_NE(ToDouble(0xFFFFFFFFFFFFFFFF), ToDouble(0xFFFFFFFFFFFFF7FF)); - EXPECT_EQ(ToDouble(0x7FFFFFFFFFFFFFFF), ToDouble(0x7FFFFFFFFFFFFC00)); - EXPECT_NE(ToDouble(0x7FFFFFFFFFFFFFFF), ToDouble(0x7FFFFFFFFFFFFBFF)); - EXPECT_EQ(ToDouble(0x3FFFFFFFFFFFFFFF), ToDouble(0x3FFFFFFFFFFFFE00)); - EXPECT_NE(ToDouble(0x3FFFFFFFFFFFFFFF), ToDouble(0x3FFFFFFFFFFFFDFF)); - - EXPECT_EQ(ToDouble(0x1000000000000001), 0.0625); - EXPECT_EQ(ToDouble(0x2000000000000001), 0.125); - EXPECT_EQ(ToDouble(0x3000000000000001), 0.1875); - EXPECT_EQ(ToDouble(0x4000000000000001), 0.25); - EXPECT_EQ(ToDouble(0x5000000000000001), 0.3125); - EXPECT_EQ(ToDouble(0x6000000000000001), 0.375); - EXPECT_EQ(ToDouble(0x7000000000000001), 0.4375); - EXPECT_EQ(ToDouble(0x8000000000000001), 0.5); - EXPECT_EQ(ToDouble(0x9000000000000001), 0.5625); - EXPECT_EQ(ToDouble(0xa000000000000001), 0.625); - EXPECT_EQ(ToDouble(0xb000000000000001), 0.6875); - EXPECT_EQ(ToDouble(0xc000000000000001), 0.75); - EXPECT_EQ(ToDouble(0xd000000000000001), 0.8125); - EXPECT_EQ(ToDouble(0xe000000000000001), 0.875); - EXPECT_EQ(ToDouble(0xf000000000000001), 0.9375); - - // Large powers of 2. - int64_t two_to_53 = int64_t{1} << 53; - EXPECT_EQ(static_cast(ToDouble(0xFFFFFFFFFFFFFFFF) * two_to_53), - two_to_53 - 1); - EXPECT_NE(static_cast(ToDouble(0xFFFFFFFFFFFFFFFF) * two_to_53 * 2), - two_to_53 * 2 - 1); - - // For values where every bit counts, the values scale as multiples of the - // input. - for (int i = 0; i < 100; ++i) { - EXPECT_EQ(i * ToDouble(0x0000000000000001), ToDouble(i)); - } - - // For each i: value generated from (1 << i). - double exp_values[64]; - exp_values[63] = 0.5; - for (int i = 62; i >= 0; --i) exp_values[i] = 0.5 * exp_values[i + 1]; - constexpr uint64_t one = 1; - for (int i = 0; i < 64; ++i) { - EXPECT_EQ(ToDouble(one << i), exp_values[i]); - for (int j = 1; j < DBL_MANT_DIG && i - j >= 0; ++j) { - EXPECT_NE(exp_values[i] + exp_values[i - j], exp_values[i]); - EXPECT_EQ(ToDouble((one << i) + (one << (i - j))), - exp_values[i] + exp_values[i - j]); - } - for (int j = DBL_MANT_DIG; i - j >= 0; ++j) { - EXPECT_EQ(exp_values[i] + exp_values[i - j], exp_values[i]); - EXPECT_EQ(ToDouble((one << i) + (one << (i - j))), exp_values[i]); - } - } -} - -TEST(GenerateRealTest, U64ToDoubleSignedTest) { - auto ToDouble = [](uint64_t a) { - return GenerateRealFromBits(a); - }; - - EXPECT_EQ(ToDouble(0x0000000000000000), 5.42101086242752217004e-20); - EXPECT_EQ(ToDouble(0x0000000000000001), 1.084202172485504434e-19); - - EXPECT_EQ(ToDouble(0x8000000000000000), -5.42101086242752217004e-20); - EXPECT_EQ(ToDouble(0x8000000000000001), -1.084202172485504434e-19); - - const double e_plus = ToDouble(0x0000000000000001); - const double e_minus = ToDouble(0x8000000000000001); - EXPECT_EQ(e_plus, 1.084202172485504434e-19); - EXPECT_EQ(e_minus, -1.084202172485504434e-19); - - EXPECT_EQ(ToDouble(0x3fffffffffffffef), 0.499999999999999944489); - EXPECT_EQ(ToDouble(0xbfffffffffffffef), -0.499999999999999944489); - - // For values > 0.5, RandU64ToDouble discards up to 10 bits. (63-53). - EXPECT_EQ(ToDouble(0x4000000000000000), 0.5); - EXPECT_EQ(ToDouble(0x4000000000000001), 0.5); - EXPECT_EQ(ToDouble(0x40000000000003FF), 0.5); - - EXPECT_EQ(ToDouble(0xC000000000000000), -0.5); - EXPECT_EQ(ToDouble(0xC000000000000001), -0.5); - EXPECT_EQ(ToDouble(0xC0000000000003FF), -0.5); - - EXPECT_EQ(ToDouble(0x7FFFFFFFFFFFFFFe), 0.999999999999999888978); - EXPECT_EQ(ToDouble(0xFFFFFFFFFFFFFFFe), -0.999999999999999888978); - - EXPECT_NE(ToDouble(0x7FFFFFFFFFFFF800), ToDouble(0x7FFFFFFFFFFFF7FF)); - - EXPECT_LT(ToDouble(0x7FFFFFFFFFFFFFFF), 1.0); - EXPECT_GT(ToDouble(0x7FFFFFFFFFFFFFFF), 0.9999999999); - - EXPECT_GT(ToDouble(0xFFFFFFFFFFFFFFFe), -1.0); - EXPECT_LT(ToDouble(0xFFFFFFFFFFFFFFFe), -0.999999999); - - EXPECT_EQ(ToDouble(0xFFFFFFFFFFFFFFFe), ToDouble(0xFFFFFFFFFFFFFC00)); - EXPECT_EQ(ToDouble(0x7FFFFFFFFFFFFFFF), ToDouble(0x7FFFFFFFFFFFFC00)); - EXPECT_NE(ToDouble(0xFFFFFFFFFFFFFFFe), ToDouble(0xFFFFFFFFFFFFF3FF)); - EXPECT_NE(ToDouble(0x7FFFFFFFFFFFFFFF), ToDouble(0x7FFFFFFFFFFFF3FF)); - - EXPECT_EQ(ToDouble(0x1000000000000001), 0.125); - EXPECT_EQ(ToDouble(0x2000000000000001), 0.25); - EXPECT_EQ(ToDouble(0x3000000000000001), 0.375); - EXPECT_EQ(ToDouble(0x4000000000000001), 0.5); - EXPECT_EQ(ToDouble(0x5000000000000001), 0.625); - EXPECT_EQ(ToDouble(0x6000000000000001), 0.75); - EXPECT_EQ(ToDouble(0x7000000000000001), 0.875); - EXPECT_EQ(ToDouble(0x7800000000000001), 0.9375); - EXPECT_EQ(ToDouble(0x7c00000000000001), 0.96875); - EXPECT_EQ(ToDouble(0x7e00000000000001), 0.984375); - EXPECT_EQ(ToDouble(0x7f00000000000001), 0.9921875); - - // 0x8000000000000000 ~= 0 - EXPECT_EQ(ToDouble(0x9000000000000001), -0.125); - EXPECT_EQ(ToDouble(0xa000000000000001), -0.25); - EXPECT_EQ(ToDouble(0xb000000000000001), -0.375); - EXPECT_EQ(ToDouble(0xc000000000000001), -0.5); - EXPECT_EQ(ToDouble(0xd000000000000001), -0.625); - EXPECT_EQ(ToDouble(0xe000000000000001), -0.75); - EXPECT_EQ(ToDouble(0xf000000000000001), -0.875); - - // Large powers of 2. - int64_t two_to_53 = int64_t{1} << 53; - EXPECT_EQ(static_cast(ToDouble(0x7FFFFFFFFFFFFFFF) * two_to_53), - two_to_53 - 1); - EXPECT_EQ(static_cast(ToDouble(0xFFFFFFFFFFFFFFFF) * two_to_53), - -(two_to_53 - 1)); - - EXPECT_NE(static_cast(ToDouble(0x7FFFFFFFFFFFFFFF) * two_to_53 * 2), - two_to_53 * 2 - 1); - - // For values where every bit counts, the values scale as multiples of the - // input. - for (int i = 1; i < 100; ++i) { - EXPECT_EQ(i * e_plus, ToDouble(i)) << i; - EXPECT_EQ(i * e_minus, ToDouble(0x8000000000000000 | i)) << i; - } -} - -TEST(GenerateRealTest, ExhaustiveFloat) { - using absl::base_internal::CountLeadingZeros64; - auto ToFloat = [](uint64_t a) { - return GenerateRealFromBits(a); - }; - - // Rely on RandU64ToFloat generating values from greatest to least when - // supplied with uint64_t values from greatest (0xfff...) to least (0x0). - // Thus, this algorithm stores the previous value, and if the new value is at - // greater than or equal to the previous value, then there is a collision in - // the generation algorithm. - // - // Use the computation below to convert the random value into a result: - // double res = a() * (1.0f - sample) + b() * sample; - float last_f = 1.0, last_g = 2.0; - uint64_t f_collisions = 0, g_collisions = 0; - uint64_t f_unique = 0, g_unique = 0; - uint64_t total = 0; - auto count = [&](const float r) { - total++; - // `f` is mapped to the range [0, 1) (default) - const float f = 0.0f * (1.0f - r) + 1.0f * r; - if (f >= last_f) { - f_collisions++; - } else { - f_unique++; - last_f = f; - } - // `g` is mapped to the range [1, 2) - const float g = 1.0f * (1.0f - r) + 2.0f * r; - if (g >= last_g) { - g_collisions++; - } else { - g_unique++; - last_g = g; - } - }; - - size_t limit = absl::GetFlag(FLAGS_absl_random_test_trials); - - // Generate all uint64_t which have unique floating point values. - // Counting down from 0xFFFFFFFFFFFFFFFFu ... 0x0u - uint64_t x = ~uint64_t(0); - for (; x != 0 && limit > 0;) { - constexpr int kDig = (64 - FLT_MANT_DIG); - // Set a decrement value & the next point at which to change - // the decrement value. By default these are 1, 0. - uint64_t dec = 1; - uint64_t chk = 0; - - // Adjust decrement and check value based on how many leading 0 - // bits are set in the current value. - const int clz = CountLeadingZeros64(x); - if (clz < kDig) { - dec <<= (kDig - clz); - chk = (~uint64_t(0)) >> (clz + 1); - } - for (; x > chk && limit > 0; x -= dec) { - count(ToFloat(x)); - --limit; - } - } - - static_assert(FLT_MANT_DIG == 24, - "The float type is expected to have a 24 bit mantissa."); - - if (limit != 0) { - // There are between 2^28 and 2^29 unique values in the range [0, 1). For - // the low values of x, there are 2^24 -1 unique values. Once x > 2^24, - // there are 40 * 2^24 unique values. Thus: - // (2 + 4 + 8 ... + 2^23) + 40 * 2^23 - EXPECT_LT(1 << 28, f_unique); - EXPECT_EQ((1 << 24) + 40 * (1 << 23) - 1, f_unique); - EXPECT_EQ(total, f_unique); - EXPECT_EQ(0, f_collisions); - - // Expect at least 2^23 unique values for the range [1, 2) - EXPECT_LE(1 << 23, g_unique); - EXPECT_EQ(total - g_unique, g_collisions); - } -} - -} // namespace -- cgit 1.4.1