#include <cilk.h>
#include <cilk-lib.h>
#include <stdlib.h>
#include <stdio.h>

cilk double sum(double* A, int n)
{
  int i,nhalf;
  double s1,s2,s;

  if (n < 10000) {
    s = 0.0;
    for (i=0; i<n; i++) s += A[i];
    return s;
  } else {
    nhalf = n/2;
    s1 = spawn sum(A,nhalf);
    s2 = spawn sum(A+nhalf,n-nhalf);
    sync;
    return (s1+s2);
  }
}

cilk int main(int argc, char *argv[])
{
  int     n, i;
  double  result;
  double* A;
  
  if (argc != 2) {
    fprintf(stderr, "Usage: sum [<cilk options>] <n>\n");
    Cilk_exit(1);
  }
  n = atoi(argv[1]);
  A = (double*) malloc(n * sizeof(double));
  for (i=0; i<n; i++) A[i] = 1.0;
  for (i=0; i<100; i++) 
    result = spawn sum(A,n);
  sync;
  
  printf("Result: %f\n", result);
  return 0;
}