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

#define ARRAY_SIZE 10000000
#define REPEAT     100


// Edit this function
void v_add(double* x, double* y, double* z) {
    #pragma omp parallel
    {
        for(int i=0; i<ARRAY_SIZE; i++) {
            z[i] = x[i] + y[i];
        }
    }
}

double* gen_array(int n) {
    double* array = (double*) malloc(n*sizeof(double));
    for(int i=0; i<n; i++) {
        array[i] = rand()%10000;
    }
    return array;
}

// Double check if it is correct
int verify(double* x, double* y) {
    double *z_v_add = (double*) malloc(ARRAY_SIZE*sizeof(double));
    double *z_oracle = (double*) malloc(ARRAY_SIZE*sizeof(double));
    v_add(x, y, z_v_add);
    for(int i=0; i<ARRAY_SIZE; i++) {
        z_oracle[i] = x[i] + y[i];
    }
    for(int i=0; i<ARRAY_SIZE; i++) {
        if(z_oracle[i] != z_v_add[i]) {
            return 0;
        }
    }
    return 1;
}


int main() {
    // Generate input vectors and destination vector
    double *x = gen_array(ARRAY_SIZE);
    double *y = gen_array(ARRAY_SIZE);
    double *z = (double*) malloc(ARRAY_SIZE*sizeof(double));

    // Double check v_add is correct
    if(!verify(x,y)) {
        printf("v_add does not match oracle\n");
        return 0;
    }
        
    // Test framework that sweeps the number of threads and times each ru
    double start_time, run_time;
    int num_threads = omp_get_max_threads();    
    for(int i=1; i<=num_threads; i++) {
        omp_set_num_threads(i);     
        start_time = omp_get_wtime();
        for(int j=0; j<REPEAT; j++) {
            v_add(x,y,z);
        }
        run_time = omp_get_wtime() - start_time;
        printf(" %d thread(s) took %f seconds\n",i,run_time);
    }
}