gcc/libgomp/testsuite/libgomp.c/omp_reduction.c

36 lines
1.0 KiB
C

/******************************************************************************
* 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;
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;
#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;
}