1 /*
2 //@HEADER
3 // ************************************************************************
4 //
5 // Kokkos v. 3.0
6 // Copyright (2020) National Technology & Engineering
7 // Solutions of Sandia, LLC (NTESS).
8 //
9 // Under the terms of Contract DE-NA0003525 with NTESS,
10 // the U.S. Government retains certain rights in this software.
11 //
12 // Redistribution and use in source and binary forms, with or without
13 // modification, are permitted provided that the following conditions are
14 // met:
15 //
16 // 1. Redistributions of source code must retain the above copyright
17 // notice, this list of conditions and the following disclaimer.
18 //
19 // 2. Redistributions in binary form must reproduce the above copyright
20 // notice, this list of conditions and the following disclaimer in the
21 // documentation and/or other materials provided with the distribution.
22 //
23 // 3. Neither the name of the Corporation nor the names of the
24 // contributors may be used to endorse or promote products derived from
25 // this software without specific prior written permission.
26 //
27 // THIS SOFTWARE IS PROVIDED BY NTESS "AS IS" AND ANY
28 // EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
29 // IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
30 // PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL NTESS OR THE
31 // CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
32 // EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
33 // PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
34 // PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
35 // LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
36 // NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
37 // SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
38 //
39 // Questions? Contact Christian R. Trott (crtrott@sandia.gov)
40 //
41 // ************************************************************************
42 //@HEADER
43 */
44
45 #include <Kokkos_Core.hpp>
46 #include <cstdio>
47
48 struct CountFunctor {
operator ()CountFunctor49 KOKKOS_FUNCTION void operator()(const long i, long& lcount) const {
50 lcount += (i % 2) == 0;
51 }
52 };
53
main(int argc,char * argv[])54 int main(int argc, char* argv[]) {
55 Kokkos::initialize(argc, argv);
56 Kokkos::DefaultExecutionSpace::print_configuration(std::cout);
57
58 if (argc < 2) {
59 fprintf(stderr, "Usage: %s [<kokkos_options>] <size>\n", argv[0]);
60 Kokkos::finalize();
61 exit(1);
62 }
63
64 const long n = strtol(argv[1], nullptr, 10);
65
66 printf("Number of even integers from 0 to %ld\n", n - 1);
67
68 Kokkos::Timer timer;
69 timer.reset();
70
71 // Compute the number of even integers from 0 to n-1, in parallel.
72 long count = 0;
73 CountFunctor functor;
74 Kokkos::parallel_reduce(n, functor, count);
75
76 double count_time = timer.seconds();
77 printf(" Parallel: %ld %10.6f\n", count, count_time);
78
79 timer.reset();
80
81 // Compare to a sequential loop.
82 long seq_count = 0;
83 for (long i = 0; i < n; ++i) {
84 seq_count += (i % 2) == 0;
85 }
86
87 count_time = timer.seconds();
88 printf("Sequential: %ld %10.6f\n", seq_count, count_time);
89
90 Kokkos::finalize();
91
92 return (count == seq_count) ? 0 : -1;
93 }
94