libgomp/testsuite/libgomp.c/omp_workshare2.c

   1 /******************************************************************************
   2 * FILE: omp_workshare2.c
   3 * DESCRIPTION:
   4 *   OpenMP Example - Sections Work-sharing - C/C++ Version
   5 *   In this example, the OpenMP SECTION directive is used to assign
   6 *   different array operations to threads that execute a SECTION. Each
   7 *   thread receives its own copy of the result array to work with.
   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 N     50
  15
  16 int main (int argc, char *argv[]) {
  17
  18 int i, nthreads, tid;
  19 float a[N], b[N], c[N];
  20
  21 /* Some initializations */
  22 for (i=0; i<N; i++)
  23   a[i] = b[i] = i * 1.0;
  24
  25 #pragma omp parallel shared(a,b,nthreads) private(c,i,tid)
  26   {
  27   tid = omp_get_thread_num();
  28   if (tid == 0)
  29     {
  30     nthreads = omp_get_num_threads();
  31     printf("Number of threads = %d\n", nthreads);
  32     }
  33   printf("Thread %d starting...\n",tid);
  34
  35   #pragma omp sections nowait
  36     {
  37     #pragma omp section
  38       {
  39       printf("Thread %d doing section 1\n",tid);
  40       for (i=0; i<N; i++)
  41         {
  42         c[i] = a[i] + b[i];
  43         printf("Thread %d: c[%d]= %f\n",tid,i,c[i]);
  44         }
  45       }
  46
  47     #pragma omp section
  48       {
  49       printf("Thread %d doing section 2\n",tid);
  50       for (i=0; i<N; i++)
  51         {
  52         c[i] = a[i] * b[i];
  53         printf("Thread %d: c[%d]= %f\n",tid,i,c[i]);
  54         }
  55       }
  56
  57     }  /* end of sections */
  58
  59     printf("Thread %d done.\n",tid);
  60
  61   }  /* end of parallel section */
  62
  63   return 0;
  64 }