/*
 * integrade_mp.c
 * 
 * A prgram integrate the function y=x^2 from 0 to 2.
 *
 */

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

/* you can adjust this to get reasonable running time on your computer */
#define NUM_STEPS (1<<29)

int main(int argc, char *argv[])
{
  double start, stop; /* for keeping track of running time */
  double sum;
  double x;
  int i;

  /* time starts now */
  start = clock();

  sum = 0;
#pragma omp parallel for reduction(+: sum)
  for (i = 0; i<NUM_STEPS; i++) {
    x = 2.0 * (double)i / (double)(NUM_STEPS); /* value of x */
    sum += x * x / NUM_STEPS;
  }

  /* we're done so stop the timer */
  stop = clock();

  printf("found result %f in %.3f seconds\n", sum, (stop-start)/1000);

  return 0;
}