1 // -*- C++ -*-
2 //===-- nth_element.pass.cpp ----------------------------------------------===//
3 //
4 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5 // See https://llvm.org/LICENSE.txt for license information.
6 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #include "support/pstl_test_config.h"
11 
12 #include <iostream>
13 #include <execution>
14 #include <algorithm>
15 
16 #include "support/utils.h"
17 
18 using namespace TestUtils;
19 
20 // User defined type with minimal requirements
21 template <typename T>
22 struct DataType
23 {
24     explicit DataType(int32_t k) : my_val(k) {}
25     DataType(DataType&& input)
26     {
27         my_val = std::move(input.my_val);
28         input.my_val = T(0);
29     }
30     DataType&
31     operator=(DataType&& input)
32     {
33         my_val = std::move(input.my_val);
34         input.my_val = T(0);
35         return *this;
36     }
37     T
38     get_val() const
39     {
40         return my_val;
41     }
42 
43     friend std::ostream&
44     operator<<(std::ostream& stream, const DataType<T>& input)
45     {
46         return stream << input.my_val;
47     }
48 
49   private:
50     T my_val;
51 };
52 
53 template <typename T>
54 bool
55 is_equal(const DataType<T>& x, const DataType<T>& y)
56 {
57     return x.get_val() == y.get_val();
58 }
59 
60 template <typename T>
61 bool
62 is_equal(const T& x, const T& y)
63 {
64     return x == y;
65 }
66 
67 struct test_one_policy
68 {
69 #if _PSTL_ICC_17_VC141_TEST_SIMD_LAMBDA_DEBUG_32_BROKEN ||                                                            \
70     _PSTL_ICC_16_VC14_TEST_SIMD_LAMBDA_DEBUG_32_BROKEN // dummy specialization by policy type, in case of broken configuration
71     template <typename Iterator1, typename Size, typename Generator1, typename Generator2, typename Compare>
72     typename std::enable_if<is_same_iterator_category<Iterator1, std::random_access_iterator_tag>::value, void>::type
73     operator()(pstl::execution::unsequenced_policy, Iterator1 first1, Iterator1 last1, Iterator1 first2,
74                Iterator1 last2, Size n, Size m, Generator1 generator1, Generator2 generator2, Compare comp)
75     {
76     }
77     template <typename Iterator1, typename Size, typename Generator1, typename Generator2, typename Compare>
78     typename std::enable_if<is_same_iterator_category<Iterator1, std::random_access_iterator_tag>::value, void>::type
79     operator()(pstl::execution::parallel_unsequenced_policy, Iterator1 first1, Iterator1 last1, Iterator1 first2,
80                Iterator1 last2, Size n, Size m, Generator1 generator1, Generator2 generator2, Compare comp)
81     {
82     }
83 #endif
84 
85     // nth_element works only with random access iterators
86     template <typename Policy, typename Iterator1, typename Size, typename Generator1, typename Generator2,
87               typename Compare>
88     typename std::enable_if<is_same_iterator_category<Iterator1, std::random_access_iterator_tag>::value, void>::type
89     operator()(Policy&& exec, Iterator1 first1, Iterator1 last1, Iterator1 first2, Iterator1 last2, Size n, Size m,
90                Generator1 generator1, Generator2 generator2, Compare comp)
91     {
92 
93         using T = typename std::iterator_traits<Iterator1>::value_type;
94         const Iterator1 mid1 = std::next(first1, m);
95         const Iterator1 mid2 = std::next(first2, m);
96 
97         fill_data(first1, mid1, generator1);
98         fill_data(mid1, last1, generator2);
99         fill_data(first2, mid2, generator1);
100         fill_data(mid2, last2, generator2);
101         std::nth_element(first1, mid1, last1, comp);
102         std::nth_element(exec, first2, mid2, last2, comp);
103         if (m > 0 && m < n)
104         {
105             EXPECT_TRUE(is_equal(*mid1, *mid2), "wrong result from nth_element with predicate");
106         }
107         EXPECT_TRUE(std::find_first_of(first2, mid2, mid2, last2, [comp](T& x, T& y) { return comp(y, x); }) == mid2,
108                     "wrong effect from nth_element with predicate");
109     }
110 
111     template <typename Policy, typename Iterator1, typename Size, typename Generator1, typename Generator2,
112               typename Compare>
113     typename std::enable_if<!is_same_iterator_category<Iterator1, std::random_access_iterator_tag>::value, void>::type
114     operator()(Policy&& exec, Iterator1 first1, Iterator1 last1, Iterator1 first2, Iterator1 last2, Size n, Size m,
115                Generator1 generator1, Generator2 generator2, Compare comp)
116     {
117     }
118 };
119 
120 template <typename T, typename Generator1, typename Generator2, typename Compare>
121 void
122 test_by_type(Generator1 generator1, Generator2 generator2, Compare comp)
123 {
124     using namespace std;
125     size_t max_size = 10000;
126     Sequence<T> in1(max_size, [](size_t v) { return T(v); });
127     Sequence<T> exp(max_size, [](size_t v) { return T(v); });
128     size_t m;
129 
130     for (size_t n = 0; n <= max_size; n = n <= 16 ? n + 1 : size_t(3.1415 * n))
131     {
132         m = 0;
133         invoke_on_all_policies(test_one_policy(), exp.begin(), exp.begin() + n, in1.begin(), in1.begin() + n, n, m,
134                                generator1, generator2, comp);
135         m = n / 7;
136         invoke_on_all_policies(test_one_policy(), exp.begin(), exp.begin() + n, in1.begin(), in1.begin() + n, n, m,
137                                generator1, generator2, comp);
138         m = 3 * n / 5;
139         invoke_on_all_policies(test_one_policy(), exp.begin(), exp.begin() + n, in1.begin(), in1.begin() + n, n, m,
140                                generator1, generator2, comp);
141     }
142     invoke_on_all_policies(test_one_policy(), exp.begin(), exp.begin() + max_size, in1.begin(), in1.begin() + max_size,
143                            max_size, max_size, generator1, generator2, comp);
144 }
145 
146 template <typename T>
147 struct test_non_const
148 {
149     template <typename Policy, typename Iterator>
150     void
151     operator()(Policy&& exec, Iterator iter)
152     {
153         invoke_if(exec, [&]() { nth_element(exec, iter, iter, iter, non_const(std::less<T>())); });
154     }
155 };
156 
157 int32_t
158 main()
159 {
160     test_by_type<int32_t>([](int32_t i) { return 10 * i; }, [](int32_t i) { return i + 1; }, std::less<int32_t>());
161     test_by_type<int32_t>([](int32_t) { return 0; }, [](int32_t) { return 0; }, std::less<int32_t>());
162 
163     test_by_type<float64_t>([](int32_t i) { return -2 * i; }, [](int32_t i) { return -(2 * i + 1); },
164                             [](const float64_t x, const float64_t y) { return x > y; });
165 
166     test_by_type<DataType<float32_t>>(
167         [](int32_t i) { return DataType<float32_t>(2 * i + 1); }, [](int32_t i) { return DataType<float32_t>(2 * i); },
168         [](const DataType<float32_t>& x, const DataType<float32_t>& y) { return x.get_val() < y.get_val(); });
169 
170     test_algo_basic_single<int32_t>(run_for_rnd<test_non_const<int32_t>>());
171 
172     std::cout << done() << std::endl;
173     return 0;
174 }
175