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Diffstat (limited to 'absl/random/internal/uniform_helper_test.cc')
| -rw-r--r-- | absl/random/internal/uniform_helper_test.cc | 279 |
1 files changed, 279 insertions, 0 deletions
diff --git a/absl/random/internal/uniform_helper_test.cc b/absl/random/internal/uniform_helper_test.cc new file mode 100644 index 00000000..173c49b0 --- /dev/null +++ b/absl/random/internal/uniform_helper_test.cc @@ -0,0 +1,279 @@ +// 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/uniform_helper.h" + +#include <cmath> +#include <cstdint> +#include <random> + +#include "gtest/gtest.h" + +namespace { + +using absl::IntervalClosedClosedTag; +using absl::IntervalClosedOpenTag; +using absl::IntervalOpenClosedTag; +using absl::IntervalOpenOpenTag; +using absl::random_internal::uniform_inferred_return_t; +using absl::random_internal::uniform_lower_bound; +using absl::random_internal::uniform_upper_bound; + +class UniformHelperTest : public testing::Test {}; + +TEST_F(UniformHelperTest, UniformBoundFunctionsGeneral) { + constexpr IntervalClosedClosedTag IntervalClosedClosed; + constexpr IntervalClosedOpenTag IntervalClosedOpen; + constexpr IntervalOpenClosedTag IntervalOpenClosed; + constexpr IntervalOpenOpenTag IntervalOpenOpen; + + // absl::uniform_int_distribution natively assumes IntervalClosedClosed + // absl::uniform_real_distribution natively assumes IntervalClosedOpen + + EXPECT_EQ(uniform_lower_bound(IntervalOpenClosed, 0, 100), 1); + EXPECT_EQ(uniform_lower_bound(IntervalOpenOpen, 0, 100), 1); + EXPECT_GT(uniform_lower_bound<float>(IntervalOpenClosed, 0, 1.0), 0); + EXPECT_GT(uniform_lower_bound<float>(IntervalOpenOpen, 0, 1.0), 0); + EXPECT_GT(uniform_lower_bound<double>(IntervalOpenClosed, 0, 1.0), 0); + EXPECT_GT(uniform_lower_bound<double>(IntervalOpenOpen, 0, 1.0), 0); + + EXPECT_EQ(uniform_lower_bound(IntervalClosedClosed, 0, 100), 0); + EXPECT_EQ(uniform_lower_bound(IntervalClosedOpen, 0, 100), 0); + EXPECT_EQ(uniform_lower_bound<float>(IntervalClosedClosed, 0, 1.0), 0); + EXPECT_EQ(uniform_lower_bound<float>(IntervalClosedOpen, 0, 1.0), 0); + EXPECT_EQ(uniform_lower_bound<double>(IntervalClosedClosed, 0, 1.0), 0); + EXPECT_EQ(uniform_lower_bound<double>(IntervalClosedOpen, 0, 1.0), 0); + + EXPECT_EQ(uniform_upper_bound(IntervalOpenOpen, 0, 100), 99); + EXPECT_EQ(uniform_upper_bound(IntervalClosedOpen, 0, 100), 99); + EXPECT_EQ(uniform_upper_bound<float>(IntervalOpenOpen, 0, 1.0), 1.0); + EXPECT_EQ(uniform_upper_bound<float>(IntervalClosedOpen, 0, 1.0), 1.0); + EXPECT_EQ(uniform_upper_bound<double>(IntervalOpenOpen, 0, 1.0), 1.0); + EXPECT_EQ(uniform_upper_bound<double>(IntervalClosedOpen, 0, 1.0), 1.0); + + EXPECT_EQ(uniform_upper_bound(IntervalOpenClosed, 0, 100), 100); + EXPECT_EQ(uniform_upper_bound(IntervalClosedClosed, 0, 100), 100); + EXPECT_GT(uniform_upper_bound<float>(IntervalOpenClosed, 0, 1.0), 1.0); + EXPECT_GT(uniform_upper_bound<float>(IntervalClosedClosed, 0, 1.0), 1.0); + EXPECT_GT(uniform_upper_bound<double>(IntervalOpenClosed, 0, 1.0), 1.0); + EXPECT_GT(uniform_upper_bound<double>(IntervalClosedClosed, 0, 1.0), 1.0); + + // Negative value tests + EXPECT_EQ(uniform_lower_bound(IntervalOpenClosed, -100, -1), -99); + EXPECT_EQ(uniform_lower_bound(IntervalOpenOpen, -100, -1), -99); + EXPECT_GT(uniform_lower_bound<float>(IntervalOpenClosed, -2.0, -1.0), -2.0); + EXPECT_GT(uniform_lower_bound<float>(IntervalOpenOpen, -2.0, -1.0), -2.0); + EXPECT_GT(uniform_lower_bound<double>(IntervalOpenClosed, -2.0, -1.0), -2.0); + EXPECT_GT(uniform_lower_bound<double>(IntervalOpenOpen, -2.0, -1.0), -2.0); + + EXPECT_EQ(uniform_lower_bound(IntervalClosedClosed, -100, -1), -100); + EXPECT_EQ(uniform_lower_bound(IntervalClosedOpen, -100, -1), -100); + EXPECT_EQ(uniform_lower_bound<float>(IntervalClosedClosed, -2.0, -1.0), -2.0); + EXPECT_EQ(uniform_lower_bound<float>(IntervalClosedOpen, -2.0, -1.0), -2.0); + EXPECT_EQ(uniform_lower_bound<double>(IntervalClosedClosed, -2.0, -1.0), + -2.0); + EXPECT_EQ(uniform_lower_bound<double>(IntervalClosedOpen, -2.0, -1.0), -2.0); + + EXPECT_EQ(uniform_upper_bound(IntervalOpenOpen, -100, -1), -2); + EXPECT_EQ(uniform_upper_bound(IntervalClosedOpen, -100, -1), -2); + EXPECT_EQ(uniform_upper_bound<float>(IntervalOpenOpen, -2.0, -1.0), -1.0); + EXPECT_EQ(uniform_upper_bound<float>(IntervalClosedOpen, -2.0, -1.0), -1.0); + EXPECT_EQ(uniform_upper_bound<double>(IntervalOpenOpen, -2.0, -1.0), -1.0); + EXPECT_EQ(uniform_upper_bound<double>(IntervalClosedOpen, -2.0, -1.0), -1.0); + + EXPECT_EQ(uniform_upper_bound(IntervalOpenClosed, -100, -1), -1); + EXPECT_EQ(uniform_upper_bound(IntervalClosedClosed, -100, -1), -1); + EXPECT_GT(uniform_upper_bound<float>(IntervalOpenClosed, -2.0, -1.0), -1.0); + EXPECT_GT(uniform_upper_bound<float>(IntervalClosedClosed, -2.0, -1.0), -1.0); + EXPECT_GT(uniform_upper_bound<double>(IntervalOpenClosed, -2.0, -1.0), -1.0); + EXPECT_GT(uniform_upper_bound<double>(IntervalClosedClosed, -2.0, -1.0), + -1.0); + + EXPECT_GT(uniform_lower_bound(IntervalOpenClosed, 1.0, 2.0), 1.0); + EXPECT_LT(uniform_lower_bound(IntervalOpenClosed, 1.0, +0.0), 1.0); + EXPECT_LT(uniform_lower_bound(IntervalOpenClosed, 1.0, -0.0), 1.0); + EXPECT_LT(uniform_lower_bound(IntervalOpenClosed, 1.0, -1.0), 1.0); +} + +TEST_F(UniformHelperTest, UniformBoundFunctionsIntBounds) { + // Verifies the saturating nature of uniform_lower_bound and + // uniform_upper_bound + constexpr IntervalOpenOpenTag IntervalOpenOpen; + + // uint max. + constexpr auto m = (std::numeric_limits<uint64_t>::max)(); + + EXPECT_EQ(1, uniform_lower_bound(IntervalOpenOpen, 0u, 0u)); + EXPECT_EQ(m, uniform_lower_bound(IntervalOpenOpen, m, m)); + EXPECT_EQ(m, uniform_lower_bound(IntervalOpenOpen, m - 1, m - 1)); + EXPECT_EQ(0, uniform_upper_bound(IntervalOpenOpen, 0u, 0u)); + EXPECT_EQ(m - 1, uniform_upper_bound(IntervalOpenOpen, m, m)); + + // int min/max + constexpr auto l = (std::numeric_limits<int64_t>::min)(); + constexpr auto r = (std::numeric_limits<int64_t>::max)(); + EXPECT_EQ(1, uniform_lower_bound(IntervalOpenOpen, 0, 0)); + EXPECT_EQ(l + 1, uniform_lower_bound(IntervalOpenOpen, l, l)); + EXPECT_EQ(r, uniform_lower_bound(IntervalOpenOpen, r - 1, r - 1)); + EXPECT_EQ(r, uniform_lower_bound(IntervalOpenOpen, r, r)); + EXPECT_EQ(-1, uniform_upper_bound(IntervalOpenOpen, 0, 0)); + EXPECT_EQ(l, uniform_upper_bound(IntervalOpenOpen, l, l)); + EXPECT_EQ(r - 1, uniform_upper_bound(IntervalOpenOpen, r, r)); +} + +TEST_F(UniformHelperTest, UniformBoundFunctionsRealBounds) { + // absl::uniform_real_distribution natively assumes IntervalClosedOpen; + // use the inverse here so each bound has to change. + constexpr IntervalOpenClosedTag IntervalOpenClosed; + + // Edge cases: the next value toward itself is itself. + EXPECT_EQ(1.0, uniform_lower_bound(IntervalOpenClosed, 1.0, 1.0)); + EXPECT_EQ(1.0f, uniform_lower_bound(IntervalOpenClosed, 1.0f, 1.0f)); + + // rightmost and leftmost finite values. + constexpr auto r = (std::numeric_limits<double>::max)(); + const auto re = std::nexttoward(r, 0.0); + constexpr auto l = -r; + const auto le = std::nexttoward(l, 0.0); + + EXPECT_EQ(l, uniform_lower_bound(IntervalOpenClosed, l, l)); // (l,l) + EXPECT_EQ(r, uniform_lower_bound(IntervalOpenClosed, r, r)); // (r,r) + EXPECT_EQ(le, uniform_lower_bound(IntervalOpenClosed, l, r)); // (l,r) + EXPECT_EQ(le, uniform_lower_bound(IntervalOpenClosed, l, 0.0)); // (l, 0) + EXPECT_EQ(le, uniform_lower_bound(IntervalOpenClosed, l, le)); // (l, le) + EXPECT_EQ(r, uniform_lower_bound(IntervalOpenClosed, re, r)); // (re, r) + + EXPECT_EQ(le, uniform_upper_bound(IntervalOpenClosed, l, l)); // (l,l) + EXPECT_EQ(r, uniform_upper_bound(IntervalOpenClosed, r, r)); // (r,r) + EXPECT_EQ(r, uniform_upper_bound(IntervalOpenClosed, l, r)); // (l,r) + EXPECT_EQ(r, uniform_upper_bound(IntervalOpenClosed, l, re)); // (l,re) + EXPECT_EQ(r, uniform_upper_bound(IntervalOpenClosed, 0.0, r)); // (0, r) + EXPECT_EQ(r, uniform_upper_bound(IntervalOpenClosed, re, r)); // (re, r) + EXPECT_EQ(r, uniform_upper_bound(IntervalOpenClosed, le, re)); // (le, re) + + const double e = std::nextafter(1.0, 2.0); // 1 + epsilon + const double f = std::nextafter(1.0, 0.0); // 1 - epsilon + + // (1.0, 1.0 + epsilon) + EXPECT_EQ(e, uniform_lower_bound(IntervalOpenClosed, 1.0, e)); + EXPECT_EQ(std::nextafter(e, 2.0), + uniform_upper_bound(IntervalOpenClosed, 1.0, e)); + + // (1.0-epsilon, 1.0) + EXPECT_EQ(1.0, uniform_lower_bound(IntervalOpenClosed, f, 1.0)); + EXPECT_EQ(e, uniform_upper_bound(IntervalOpenClosed, f, 1.0)); + + // denorm cases. + const double g = std::numeric_limits<double>::denorm_min(); + const double h = std::nextafter(g, 1.0); + + // (0, denorm_min) + EXPECT_EQ(g, uniform_lower_bound(IntervalOpenClosed, 0.0, g)); + EXPECT_EQ(h, uniform_upper_bound(IntervalOpenClosed, 0.0, g)); + + // (denorm_min, 1.0) + EXPECT_EQ(h, uniform_lower_bound(IntervalOpenClosed, g, 1.0)); + EXPECT_EQ(e, uniform_upper_bound(IntervalOpenClosed, g, 1.0)); + + // Edge cases: invalid bounds. + EXPECT_EQ(f, uniform_lower_bound(IntervalOpenClosed, 1.0, -1.0)); +} + +struct Invalid {}; + +template <typename A, typename B> +auto InferredUniformReturnT(int) -> uniform_inferred_return_t<A, B>; + +template <typename, typename> +Invalid InferredUniformReturnT(...); + +// Given types <A, B, Expect>, CheckArgsInferType() verifies that +// +// uniform_inferred_return_t<A, B> and +// uniform_inferred_return_t<B, A> +// +// returns the type "Expect". +// +// This interface can also be used to assert that a given inferred return types +// are invalid. Writing: +// +// CheckArgsInferType<float, int, Invalid>() +// +// will assert that this overload does not exist. +template <typename A, typename B, typename Expect> +void CheckArgsInferType() { + static_assert( + absl::conjunction< + std::is_same<Expect, decltype(InferredUniformReturnT<A, B>(0))>, + std::is_same<Expect, + decltype(InferredUniformReturnT<B, A>(0))>>::value, + ""); +} + +TEST_F(UniformHelperTest, UniformTypeInference) { + // Infers common types. + CheckArgsInferType<uint16_t, uint16_t, uint16_t>(); + CheckArgsInferType<uint32_t, uint32_t, uint32_t>(); + CheckArgsInferType<uint64_t, uint64_t, uint64_t>(); + CheckArgsInferType<int16_t, int16_t, int16_t>(); + CheckArgsInferType<int32_t, int32_t, int32_t>(); + CheckArgsInferType<int64_t, int64_t, int64_t>(); + CheckArgsInferType<float, float, float>(); + CheckArgsInferType<double, double, double>(); + + // Properly promotes uint16_t. + CheckArgsInferType<uint16_t, uint32_t, uint32_t>(); + CheckArgsInferType<uint16_t, uint64_t, uint64_t>(); + CheckArgsInferType<uint16_t, int32_t, int32_t>(); + CheckArgsInferType<uint16_t, int64_t, int64_t>(); + CheckArgsInferType<uint16_t, float, float>(); + CheckArgsInferType<uint16_t, double, double>(); + + // Properly promotes int16_t. + CheckArgsInferType<int16_t, int32_t, int32_t>(); + CheckArgsInferType<int16_t, int64_t, int64_t>(); + CheckArgsInferType<int16_t, float, float>(); + CheckArgsInferType<int16_t, double, double>(); + + // Invalid (u)int16_t-pairings do not compile. + // See "CheckArgsInferType" comments above, for how this is achieved. + CheckArgsInferType<uint16_t, int16_t, Invalid>(); + CheckArgsInferType<int16_t, uint32_t, Invalid>(); + CheckArgsInferType<int16_t, uint64_t, Invalid>(); + + // Properly promotes uint32_t. + CheckArgsInferType<uint32_t, uint64_t, uint64_t>(); + CheckArgsInferType<uint32_t, int64_t, int64_t>(); + CheckArgsInferType<uint32_t, double, double>(); + + // Properly promotes int32_t. + CheckArgsInferType<int32_t, int64_t, int64_t>(); + CheckArgsInferType<int32_t, double, double>(); + + // Invalid (u)int32_t-pairings do not compile. + CheckArgsInferType<uint32_t, int32_t, Invalid>(); + CheckArgsInferType<int32_t, uint64_t, Invalid>(); + CheckArgsInferType<int32_t, float, Invalid>(); + CheckArgsInferType<uint32_t, float, Invalid>(); + + // Invalid (u)int64_t-pairings do not compile. + CheckArgsInferType<uint64_t, int64_t, Invalid>(); + CheckArgsInferType<int64_t, float, Invalid>(); + CheckArgsInferType<int64_t, double, Invalid>(); + + // Properly promotes float. + CheckArgsInferType<float, double, double>(); +} + +} // namespace |