/******************************************************************************
* FILE: omp_reduction.c
* DESCRIPTION:
*   OpenMP Example - Combined Parallel Loop Reduction - C/C++ Version
*   This example demonstrates a sum reduction within a combined parallel loop
*   construct.  Notice that default data element scoping is assumed - there
*   are no clauses specifying shared or private variables.  OpenMP will 
*   automatically make loop index variables private within team threads, and
*   global variables shared.
* AUTHOR: Blaise Barney  5/99
* LAST REVISED: 04/06/05
******************************************************************************/
#include <omp.h>
#include <stdio.h>
#include <stdlib.h>

int main (int argc, char *argv[]) 
{
   int   i, n, numt, procs;
   float a[100], b[100], sum; 

/* Some initializations */
   n = 100;
   for (i=0; i < n; i++)
        a[i] = b[i] = i * 1.0;
   sum = 0.0;
/* Set the number of threads to the number of processors */
   procs = omp_get_num_procs();
   omp_set_num_threads(procs);  
   numt = omp_get_num_threads();
   printf("number of threads = %d\n",numt);
#pragma omp parallel for reduction(+:sum)
  for (i=0; i < n; i++)
    sum = sum + (a[i] * b[i]);

  printf("   Sum = %f\n",sum);
  return 0;

}