#include "stdio.h"
#include <stdlib.h>
#include <stdint.h>
#include <time.h>

#include <omp.h>
#include <math.h>

int main(int argc, char **argv)
{
    int N;
    int nb_thread;
    double start; 
    double end; 

    if (argc == 3){
        N = atoi(argv[1]);
        nb_thread = atoi(argv[2]);

        printf("Nb thread max %d\n", nb_thread);
        printf("N %d\n", N);
    } else {
        printf("Missing parameters\n\r");
        return EXIT_FAILURE;
    }

    srand(time(NULL));

    double x[N], y = 0;
    for(int i=0; i<N; i++)x[i]=rand();

    double mean_s = 0, mean_omp = 0;
    int boucle = 10000;
    printf("Mean time on %d executions\n", boucle);

    for(int t=0; t<boucle;t++){
        start = omp_get_wtime(); 
        for(int i=0; i<N; i++){
            y += x[i];
        }
        end = omp_get_wtime(); 
        mean_s += (end-start);
    }

    omp_set_num_threads(nb_thread);
    for(int t=0; t<boucle;t++){
        start = omp_get_wtime(); 
        // #pragma omp parallel for reduction(+:y)
        //#pragma omp parallel for schedule(guided,100)
        #pragma omp parallel for schedule(static,1000) reduction(+:y)
        for(int i=0; i<N; i++){
            // #pragma omp atomic
            // #pragma omp critical
            y += x[i];
        }
        end = omp_get_wtime(); 
        mean_omp += (end-start);
    }
    mean_s = mean_s/boucle;
    mean_omp = mean_omp/boucle;

    printf("Sequential work took %f seconds\n", mean_s);
    printf("OMP work took %f seconds\n\r", mean_omp);
    
    return 0;
}