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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
// SPDX-FileCopyrightText: Copyright Contributors to the Kokkos project
// Replaces the usual #include <Kokkos_Core.hpp>
import kokkos.core;
// We don't get any transitive includes or macro definitions when importing
// C++20 modules. Since pretty much every Kokkos-based code needs configuration
// macros, it's recommended to always include Kokkos_Macros.hpp. In this
// example, we need it for KOKKOS_LAMBDA in particular.
#include <Kokkos_Macros.hpp>
#include <iostream>
int main(int argc, char* argv[]) {
Kokkos::initialize(argc, argv);
Kokkos::DefaultExecutionSpace{}.print_configuration(std::cout);
if (argc < 2) {
std::cerr << "Usage: " << argv[0] << " [<kokkos_options>] <size>\n";
Kokkos::finalize();
exit(1);
}
const long n = strtol(argv[1], nullptr, 10);
std::cout << "Number of even integers from 0 to " << n - 1 << '\n';
Kokkos::Timer timer;
// Compute the number of even integers from 0 to n-1, in parallel.
long count = 0;
Kokkos::parallel_reduce(
n, KOKKOS_LAMBDA(const long i, long& lcount) { lcount += (i % 2) == 0; },
count);
double count_time = timer.seconds();
std::cout << " Parallel: " << count << " " << count_time << '\n';
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();
std::cout << "Sequential: " << seq_count << " " << count_time << '\n';
Kokkos::finalize();
return (count == seq_count) ? 0 : -1;
}
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