[Omp] atomic and flush

[Meadows, Lawrence F]

Your code should work with atomic if this is the only access to
the number_access array within the parallel region. Flush should
not be required. It may be a compiler problem.

Regards, Larry 

>-----Original Message-----
>From: Omp-bounces at openmp.org [mailto:Omp-bounces at openmp.org] 
>On Behalf Of Maria Jose Martin Santamaria
>Sent: Tuesday, November 16, 2004 4:20 AM
>To: omp
>Subject: [Omp] atomic and flush
>
>I have a parallel program with the following structure (simplified):
>
>C$OMP PARALLEL SHARED(INDEX,number_access,N)
>C$OMP+PRIVATE(i,re,myid,p)
>
>       myid=OMP_GET_THREAD_NUM()
>       p=OMP_GET_NUM_THREADS()
>
>       do i=myid+1,N,p
>           re=INDEX(i)
>           .....
>
>C$OMP CRITICAL
>       number_access(re)=number_access(re)+1
>C$OMP END CRITICAL
>           .....
>
>       enddo
>
>C$OMP END PARALLEL
>
>If I replace the CRITICAL directive by a ATOMIC directive the program 
>does not work. Could it be due to memory inconsistency?. 
>Should I add a 
>FLUSH directive when using ATOMIC?. If yes, is it always necessary to 
>add a FLUSH directive when using a ATOMIC directive?.
>
>Thanks in advance for your help,
>
>María J. Martín
>Computer Architecture Group
>University of A Coruña
>Spain
>
>
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