test.c

#include <stdio.h>
#include <stdlib.h>
#include <omp.h>
#include <time.h>

int main(void)
{
    int a[100000];
    double start_time, end_time;
    size_t i;

    int num_threads = omp_get_num_procs() * 2;

    // Run the original code
    start_time = (double)clock() / CLOCKS_PER_SEC;
    for (i = 0; i < 100000; i++) {
        a[i] = 2*i+i;
        printf("a[%d],%d\n", i, a[i]);
    }
    end_time = (double)clock() / CLOCKS_PER_SEC;
    double orig_time = end_time - start_time;

    // Run the modified code with increased number of threads
    start_time = (double)clock() / CLOCKS_PER_SEC;
    #pragma omp parallel for num_threads(num_threads)
    for (i = 0; i < 100000; i++) {
        a[i] = 2*i+i;
         printf("a[%d],%d\n", i, a[i]);
    }
    end_time = (double)clock() / CLOCKS_PER_SEC;
    double mod_time = end_time - start_time;

    printf("Original code: time=%.6f seconds\n", orig_time);
    printf("Modified code: time=%.6f seconds\n", mod_time);

    // Check for errors
    int errors = 0;
    for (i = 0; i < 100000; i++) {
        if (a[i] != 2*i+i) {
            printf("Error at index %d: expected %d, got %d\n", i, 2*i+i, a[i]);
            errors++;
        }
    }
    if (errors == 0) {
        printf("No errors detected.\n");
    } else {
        printf("%d errors detected.\n", errors);
    }

    // Calculate the speedup
    double speedup = orig_time / mod_time;
    printf("Speedup: %.2f\n", speedup);

    printf("Program completed successfully.\n");

    return 0;
}