/******************************************************************************
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/******************************************************************************
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* FILE: omp_workshare2.c
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* FILE: omp_workshare2.c
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* DESCRIPTION:
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* DESCRIPTION:
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* OpenMP Example - Sections Work-sharing - C/C++ Version
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* OpenMP Example - Sections Work-sharing - C/C++ Version
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* In this example, the OpenMP SECTION directive is used to assign
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* In this example, the OpenMP SECTION directive is used to assign
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* different array operations to threads that execute a SECTION. Each
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* different array operations to threads that execute a SECTION. Each
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* thread receives its own copy of the result array to work with.
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* thread receives its own copy of the result array to work with.
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* AUTHOR: Blaise Barney 5/99
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* AUTHOR: Blaise Barney 5/99
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* LAST REVISED: 04/06/05
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* LAST REVISED: 04/06/05
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******************************************************************************/
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******************************************************************************/
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#include <omp.h>
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#include <omp.h>
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#include <stdio.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <stdlib.h>
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#define N 50
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#define N 50
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int main (int argc, char *argv[]) {
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int main (int argc, char *argv[]) {
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int i, nthreads, tid;
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int i, nthreads, tid;
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float a[N], b[N], c[N];
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float a[N], b[N], c[N];
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/* Some initializations */
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/* Some initializations */
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for (i=0; i<N; i++)
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for (i=0; i<N; i++)
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a[i] = b[i] = i * 1.0;
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a[i] = b[i] = i * 1.0;
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#pragma omp parallel shared(a,b,nthreads) private(c,i,tid)
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#pragma omp parallel shared(a,b,nthreads) private(c,i,tid)
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{
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{
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tid = omp_get_thread_num();
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tid = omp_get_thread_num();
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if (tid == 0)
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if (tid == 0)
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{
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{
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nthreads = omp_get_num_threads();
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nthreads = omp_get_num_threads();
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printf("Number of threads = %d\n", nthreads);
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printf("Number of threads = %d\n", nthreads);
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}
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}
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printf("Thread %d starting...\n",tid);
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printf("Thread %d starting...\n",tid);
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#pragma omp sections nowait
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#pragma omp sections nowait
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{
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{
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#pragma omp section
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#pragma omp section
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{
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{
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printf("Thread %d doing section 1\n",tid);
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printf("Thread %d doing section 1\n",tid);
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for (i=0; i<N; i++)
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for (i=0; i<N; i++)
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{
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{
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c[i] = a[i] + b[i];
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c[i] = a[i] + b[i];
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printf("Thread %d: c[%d]= %f\n",tid,i,c[i]);
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printf("Thread %d: c[%d]= %f\n",tid,i,c[i]);
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}
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}
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}
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}
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#pragma omp section
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#pragma omp section
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{
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{
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printf("Thread %d doing section 2\n",tid);
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printf("Thread %d doing section 2\n",tid);
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for (i=0; i<N; i++)
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for (i=0; i<N; i++)
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{
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{
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c[i] = a[i] * b[i];
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c[i] = a[i] * b[i];
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printf("Thread %d: c[%d]= %f\n",tid,i,c[i]);
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printf("Thread %d: c[%d]= %f\n",tid,i,c[i]);
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}
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}
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}
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}
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} /* end of sections */
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} /* end of sections */
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printf("Thread %d done.\n",tid);
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printf("Thread %d done.\n",tid);
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} /* end of parallel section */
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} /* end of parallel section */
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return 0;
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return 0;
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}
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}
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