/******************************************************************************
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/******************************************************************************
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* FILE: omp_orphan.c
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* FILE: omp_orphan.c
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* DESCRIPTION:
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* DESCRIPTION:
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* OpenMP Example - Parallel region with an orphaned directive - C/C++ Version
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* OpenMP Example - Parallel region with an orphaned directive - C/C++ Version
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* This example demonstrates a dot product being performed by an orphaned
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* This example demonstrates a dot product being performed by an orphaned
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* loop reduction construct. Scoping of the reduction variable is critical.
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* loop reduction construct. Scoping of the reduction variable is critical.
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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 VECLEN 100
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#define VECLEN 100
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float a[VECLEN], b[VECLEN], sum;
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float a[VECLEN], b[VECLEN], sum;
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float dotprod ()
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float dotprod ()
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{
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{
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int i,tid;
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int i,tid;
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tid = omp_get_thread_num();
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tid = omp_get_thread_num();
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#pragma omp for reduction(+:sum)
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#pragma omp for reduction(+:sum)
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for (i=0; i < VECLEN; i++)
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for (i=0; i < VECLEN; i++)
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{
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{
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sum = sum + (a[i]*b[i]);
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sum = sum + (a[i]*b[i]);
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printf(" tid= %d i=%d\n",tid,i);
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printf(" tid= %d i=%d\n",tid,i);
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}
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}
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return(sum);
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return(sum);
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}
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}
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int main (int argc, char *argv[])
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int main (int argc, char *argv[])
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{
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{
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int i;
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int i;
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for (i=0; i < VECLEN; i++)
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for (i=0; i < VECLEN; i++)
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a[i] = b[i] = 1.0 * i;
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a[i] = b[i] = 1.0 * i;
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sum = 0.0;
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sum = 0.0;
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#pragma omp parallel
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#pragma omp parallel
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sum = dotprod();
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sum = dotprod();
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printf("Sum = %f\n",sum);
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printf("Sum = %f\n",sum);
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return 0;
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return 0;
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}
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}
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