Intel® C++ Compiler
Community support and assistance for creating C++ code that runs on platforms based on Intel® processors.

OpenMP collapse and private

Armando_Lazaro_Alami
707 Views

After updating into Intel(R) C++ Compiler XE 14.0.2.176 [IA-32] I found a different treatment for variables in collapsed control loops. Previously I used Intel C++ 13.x.  For version 13.xxx, the following code was correct :

int i,j,k;

#pragma omp parallel for collapse(3)
    for (k=0; k< h->nz;  k++)
    for (j=0; j< h->ny ; j++)
    for (i=0; i< h->nx ; i++)
    {
       Point3DType p3d;

       XYZ(h, i, j, k, &p3d);
       d2pc[(h->nx * h->ny)*k + h->nx * j + i] = kdNNS(&p3d);
    }

For version 14.0.2.176 it needs to be modified into:

#pragma omp parallel for collapse(3) private (k,j,i)

I had to declare as private at less j and i.

I do not know if it is mandatory to declare i and j as private according to OpenMP definition. But I found important to share my case with others because it was not easy to locate the source of the problem and there are lot of examples of use of "collapse" omitting private declaration for the control variables affected.

0 Kudos
3 Replies
TimP
Honored Contributor III
707 Views

 

duplicate thread

0 Kudos
Armando_Lazaro_Alami
707 Views

Sorry for posting several times, it took 7 hours to be published and I keep trying...

0 Kudos
QIAOMIN_Q_
New Contributor I
707 Views

Closed as duplication ,please refer to Tim's advice and my answer in this thread http://software.intel.com/en-us/forums/topic/507155

 

Thank you.
--
QIAOMIN.Q
Intel Developer Support
Please participate in our redesigned community support web site:

User forums:                   http://software.intel.com/en-us/forums/

0 Kudos
Reply