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//@HEADER
// ************************************************************************
//
// Kokkos v. 4.0
// Copyright (2022) National Technology & Engineering
// Solutions of Sandia, LLC (NTESS).
//
// Under the terms of Contract DE-NA0003525 with NTESS,
// the U.S. Government retains certain rights in this software.
//
// Part of Kokkos, under the Apache License v2.0 with LLVM Exceptions.
// See https://kokkos.org/LICENSE for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//@HEADER
#include <Kokkos_Core.hpp>
#include <iostream>
struct CountFunctor {
KOKKOS_FUNCTION void operator()(const long i, long& lcount) const {
lcount += (i % 2) == 0;
}
};
int main(int argc, char* argv[]) {
Kokkos::initialize(argc, argv);
Kokkos::DefaultExecutionSpace().print_configuration(std::cout);
if (argc < 2) {
fprintf(stderr, "Usage: %s [<kokkos_options>] <size>\n", argv[0]);
Kokkos::finalize();
exit(1);
}
const long n = strtol(argv[1], nullptr, 10);
printf("Number of even integers from 0 to %ld\n", n - 1);
Kokkos::Timer timer;
timer.reset();
// Compute the number of even integers from 0 to n-1, in parallel.
long count = 0;
CountFunctor functor;
Kokkos::parallel_reduce(n, functor, count);
double count_time = timer.seconds();
printf(" Parallel: %ld %10.6f\n", count, count_time);
timer.reset();
// Compare to a sequential loop.
long seq_count = 0;
for (long i = 0; i < n; ++i) {
seq_count += (i % 2) == 0;
}
count_time = timer.seconds();
printf("Sequential: %ld %10.6f\n", seq_count, count_time);
Kokkos::finalize();
return (count == seq_count) ? 0 : -1;
}
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