![Evgeniy Stepanov](/assets/img/avatar_default.png)
Following specification in "C++ Extensions for Library Fundamentals": http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/n4480.html#alg.random.sample git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@237264 91177308-0d34-0410-b5e6-96231b3b80d8
147 lines
5.7 KiB
C++
147 lines
5.7 KiB
C++
//===----------------------------------------------------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is dual licensed under the MIT and the University of Illinois Open
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// Source Licenses. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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// <algorithm>
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// template <class PopulationIterator, class SampleIterator, class Distance,
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// class UniformRandomNumberGenerator>
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// SampleIterator sample(PopulationIterator first, PopulationIterator last,
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// SampleIterator out, Distance n,
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// UniformRandomNumberGenerator &&g);
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#include <experimental/algorithm>
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#include <random>
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#include <cassert>
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#include "test_iterators.h"
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struct ReservoirSampleExpectations {
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enum { os = 4 };
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static int oa1[os];
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static int oa2[os];
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};
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int ReservoirSampleExpectations::oa1[] = {10, 5, 9, 4};
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int ReservoirSampleExpectations::oa2[] = {5, 2, 10, 4};
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struct SelectionSampleExpectations {
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enum { os = 4 };
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static int oa1[os];
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static int oa2[os];
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};
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int SelectionSampleExpectations::oa1[] = {1, 4, 6, 7};
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int SelectionSampleExpectations::oa2[] = {1, 2, 6, 8};
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template <class IteratorCategory> struct TestExpectations
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: public SelectionSampleExpectations {};
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template <>
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struct TestExpectations<std::input_iterator_tag>
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: public ReservoirSampleExpectations {};
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template <template<class> class PopulationIteratorType, class PopulationItem,
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template<class> class SampleIteratorType, class SampleItem>
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void test() {
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typedef PopulationIteratorType<PopulationItem *> PopulationIterator;
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typedef SampleIteratorType<SampleItem *> SampleIterator;
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PopulationItem ia[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
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const unsigned is = sizeof(ia) / sizeof(ia[0]);
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typedef TestExpectations<typename std::iterator_traits<
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PopulationIterator>::iterator_category> Expectations;
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const unsigned os = Expectations::os;
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SampleItem oa[os];
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const int *oa1 = Expectations::oa1;
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const int *oa2 = Expectations::oa2;
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std::minstd_rand g;
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SampleIterator end;
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end = std::experimental::sample(PopulationIterator(ia),
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PopulationIterator(ia + is),
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SampleIterator(oa), os, g);
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assert(&*end - oa == std::min(os, is));
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assert(std::equal(oa, oa + os, oa1));
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end = std::experimental::sample(PopulationIterator(ia),
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PopulationIterator(ia + is),
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SampleIterator(oa), os, g);
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assert(&*end - oa == std::min(os, is));
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assert(std::equal(oa, oa + os, oa2));
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}
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template <template<class> class PopulationIteratorType, class PopulationItem,
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template<class> class SampleIteratorType, class SampleItem>
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void test_empty_population() {
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typedef PopulationIteratorType<PopulationItem *> PopulationIterator;
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typedef SampleIteratorType<SampleItem *> SampleIterator;
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PopulationItem ia[] = {42};
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const unsigned os = 4;
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SampleItem oa[os];
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std::minstd_rand g;
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SampleIterator end =
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std::experimental::sample(PopulationIterator(ia), PopulationIterator(ia),
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SampleIterator(oa), os, g);
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assert(&*end == oa);
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}
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template <template<class> class PopulationIteratorType, class PopulationItem,
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template<class> class SampleIteratorType, class SampleItem>
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void test_empty_sample() {
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typedef PopulationIteratorType<PopulationItem *> PopulationIterator;
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typedef SampleIteratorType<SampleItem *> SampleIterator;
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PopulationItem ia[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
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const unsigned is = sizeof(ia) / sizeof(ia[0]);
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SampleItem oa[1];
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std::minstd_rand g;
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SampleIterator end =
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std::experimental::sample(PopulationIterator(ia), PopulationIterator(ia + is),
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SampleIterator(oa), 0, g);
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assert(&*end == oa);
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}
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template <template<class> class PopulationIteratorType, class PopulationItem,
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template<class> class SampleIteratorType, class SampleItem>
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void test_small_population() {
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// The population size is less than the sample size.
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typedef PopulationIteratorType<PopulationItem *> PopulationIterator;
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typedef SampleIteratorType<SampleItem *> SampleIterator;
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PopulationItem ia[] = {1, 2, 3, 4, 5};
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const unsigned is = sizeof(ia) / sizeof(ia[0]);
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const unsigned os = 8;
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SampleItem oa[os];
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const SampleItem oa1[] = {1, 2, 3, 4, 5};
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std::minstd_rand g;
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SampleIterator end;
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end = std::experimental::sample(PopulationIterator(ia),
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PopulationIterator(ia + is),
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SampleIterator(oa), os, g);
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assert(&*end - oa == std::min(os, is));
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assert(std::equal(oa, &*end, oa1));
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}
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int main() {
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test<input_iterator, int, random_access_iterator, int>();
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test<forward_iterator, int, output_iterator, int>();
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test<forward_iterator, int, random_access_iterator, int>();
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test<input_iterator, int, random_access_iterator, double>();
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test<forward_iterator, int, output_iterator, double>();
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test<forward_iterator, int, random_access_iterator, double>();
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test_empty_population<input_iterator, int, random_access_iterator, int>();
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test_empty_population<forward_iterator, int, output_iterator, int>();
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test_empty_population<forward_iterator, int, random_access_iterator, int>();
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test_empty_sample<input_iterator, int, random_access_iterator, int>();
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test_empty_sample<forward_iterator, int, output_iterator, int>();
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test_empty_sample<forward_iterator, int, random_access_iterator, int>();
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test_small_population<input_iterator, int, random_access_iterator, int>();
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test_small_population<forward_iterator, int, output_iterator, int>();
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test_small_population<forward_iterator, int, random_access_iterator, int>();
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}
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