HPX Comparative

hpx_for_each.cpp

#include <hpx/hpx.hpp>
#include <hpx/hpx_init.hpp>
#include <hpx/parallel/algorithms/for_each.hpp>

#include <stdio.h>
#include <chrono>
#include <cstddef>
#include <iterator>
#include <vector>
#include "stopwatch.hpp"

using namespace std;
using namespace std::chrono;

int A[3000];

template<class ExecutionPolicy>
void test(ExecutionPolicy&& exec) {
    hpx::parallel::for_each(std::forward<ExecutionPolicy>(exec), begin(A), end(A), [](int& r) {
        const int j = static_cast<int>(&r - &A[0]);
        int red = 0;
        for (int i=0; i<100000; i++) {
            red += static_cast<int>(sin(i+j) + cos(i+j));
        }
        r = red;
    });
}

///////////////////////////////////////////////////////////////////////////////
#pragma optimize("", off)
int hpx_main(boost::program_options::variables_map& vm)
{

/*
PS TEST WCFB01 C:\Users\bion\Desktop>.\hpx_for_each.exe
Testing sequential
A[70] is 1
Sequential took 3053ms

Testing parallel
A[70] is 1
Parallel took 3051ms

Speedup: 1.000580x
*/

    stopwatch sequential;
    stopwatch parallel;

    puts("Testing sequential");
    fill(begin(A), end(A), int{});
    sequential.start();
    test(hpx::parallel::execution::seq);
    sequential.stop();
    printf("A[70] is %d\n", A[70]);
    sequential.print("Sequential");

    puts("Testing parallel");
    fill(begin(A), end(A), int{});
    parallel.start();
    test(hpx::parallel::execution::par_unseq);
    parallel.stop();
    printf("A[70] is %d\n", A[70]);
    parallel.print("Parallel");

    printf("Speedup: %fx\n", parallel.compare(sequential));
    return hpx::finalize();
}
#pragma optimize("", on)

///////////////////////////////////////////////////////////////////////////////
int main(int argc, char* argv[])
{
    return hpx::init(argc, argv);
}