77 lines
2.3 KiB
C++
77 lines
2.3 KiB
C++
// Copyright 2016 Google Inc. All rights reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#include "src/weighted_reservoir_sampler.h"
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#include <numeric>
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#include <tuple>
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#include <vector>
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#include "port/gtest.h"
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using testing::Combine;
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using testing::Range;
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using testing::TestWithParam;
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using testing::ValuesIn;
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namespace protobuf_mutator {
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class WeightedReservoirSamplerTest
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: public TestWithParam<std::tuple<int, std::vector<int>>> {};
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const int kRuns = 1000000;
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const std::vector<int> kTests[] = {
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{1},
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{1, 1, 1},
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{1, 1, 0},
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{1, 10, 100},
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{100, 1, 10},
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{1, 10000, 10000},
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{1, 3, 7, 100, 105},
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{93519, 52999, 354, 37837, 55285, 31787, 89096, 55695, 1587,
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18233, 77557, 67632, 59348, 51250, 17417, 96856, 78568, 44296,
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70170, 41328, 9206, 90187, 54086, 35602, 53167, 33791, 60118,
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52962, 10327, 80513, 49526, 18326, 83662, 49644, 70903, 4910,
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36309, 19196, 42982, 53316, 14773, 86607, 60835}};
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INSTANTIATE_TEST_SUITE_P(AllTest, WeightedReservoirSamplerTest,
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Combine(Range(1, 10, 3), ValuesIn(kTests)));
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TEST_P(WeightedReservoirSamplerTest, Test) {
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std::vector<int> weights = std::get<1>(GetParam());
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std::vector<int> counts(weights.size(), 0);
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using RandomEngine = std::minstd_rand;
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RandomEngine rand(std::get<0>(GetParam()));
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for (int i = 0; i < kRuns; ++i) {
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WeightedReservoirSampler<int, RandomEngine> sampler(&rand);
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for (size_t j = 0; j < weights.size(); ++j) sampler.Try(weights[j], j);
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++counts[sampler.selected()];
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}
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int sum = std::accumulate(weights.begin(), weights.end(), 0);
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for (size_t j = 0; j < weights.size(); ++j) {
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float expected = weights[j];
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expected /= sum;
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float actual = counts[j];
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actual /= kRuns;
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EXPECT_NEAR(expected, actual, 0.01);
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}
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}
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} // namespace protobuf_mutator
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