libgomp/testsuite/libgomp.c/omp_workshare1.c

   1 /******************************************************************************
   2 * FILE: omp_workshare1.c
   3 * DESCRIPTION:
   4 *   OpenMP Example - Loop Work-sharing - C/C++ Version
   5 *   In this example, the iterations of a loop are scheduled dynamically
   6 *   across the team of threads.  A thread will perform CHUNK iterations
   7 *   at a time before being scheduled for the next CHUNK of work.
   8 * AUTHOR: Blaise Barney  5/99
   9 * LAST REVISED: 04/06/05
  10 ******************************************************************************/
  11 #include <omp.h>
  12 #include <stdio.h>
  13 #include <stdlib.h>
  14 #define CHUNKSIZE   10
  15 #define N       100
  16
  17 int main (int argc, char *argv[]) {
  18
  19 int nthreads, tid, i, chunk;
  20 float a[N], b[N], c[N];
  21
  22 /* Some initializations */
  23 for (i=0; i < N; i++)
  24   a[i] = b[i] = i * 1.0;
  25 chunk = CHUNKSIZE;
  26
  27 #pragma omp parallel shared(a,b,c,nthreads,chunk) private(i,tid)
  28   {
  29   tid = omp_get_thread_num();
  30   if (tid == 0)
  31     {
  32     nthreads = omp_get_num_threads();
  33     printf("Number of threads = %d\n", nthreads);
  34     }
  35   printf("Thread %d starting...\n",tid);
  36
  37   #pragma omp for schedule(dynamic,chunk)
  38   for (i=0; i<N; i++)
  39     {
  40     c[i] = a[i] + b[i];
  41     printf("Thread %d: c[%d]= %f\n",tid,i,c[i]);
  42     }
  43
  44   }  /* end of parallel section */
  45
  46   return 0;
  47 }