#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <omp.h>
#include <sys/time.h>

int length = 1024;
int cpu_num = 1;
void init(int argc, const char* argv[]) {
    for (int i = 1; argv[i]; ++i) {
        if (strcmp(argv[i], "-cpu") == 0)
            cpu_num = (int)atoi(argv[i+1]);
        else if (strcmp(argv[i], "-l") == 0)
            length = (int)atoi(argv[i+1]);
    }
}

int main(int argc, const char* argv[])
{
    int n;
    init(argc, argv);
    omp_set_num_threads(cpu_num);
    int *a;
    a = (int *) malloc(sizeof(int) * length);
    for (int i = 0; i < length; i++)
    {
        a[i] = i;
    }

    struct timeval tv;
    gettimeofday(&tv, NULL);
    double now = tv.tv_sec + (double)tv.tv_usec*1e-6;

#pragma omp parallel for
    for(int i = 0; i < length; i++)
    {
        a[i] = a[i] * 2;
    }

    gettimeofday(&tv, NULL);
    printf("%0.6f\n", (tv.tv_sec+(double)tv.tv_usec*1e-6) - now);

    for(int i = 0; i < length; i++)
    {
        if(a[i] != i*2) {
	    printf("fail\n");
	}
    }

    return 0;
}