[Pw_forum] Gathering 3-d arrays across pools using QE's mp_sum

[Vahid Askarpour]

Hi Ye,

Thank you for your suggestion. I tried it and when I ran the code, it seg-faulted. I put flags in the code to see where the segmentation faults occurs. It happens as the code calls mp_sum. It seems that mp_sum may not
be able to handle this reduction.

Cheers,
Vahid

On Oct 28, 2016, at 2:51 PM, Ye Luo <xw111luoye at gmail.com<mailto:xw111luoye at gmail.com>> wrote:

In Fortran, whatever-D array is 1-D array. mp_sum should be fine.
I saw something strange in your code that you were not copying the right things as you expected.
How about the following?
output(1:3,1:nbnds,(k_pool*pool_id+1:k_pool*pool_id+k_pool))=input(1:3,1:nbnds,1:k_pool)

Ye

===================
Ye Luo, Ph.D.
Leadership Computing Facility
Argonne National Laboratory

2016-10-28 12:29 GMT-05:00 Vahid Askarpour <vh261281 at dal.ca<mailto:vh261281 at dal.ca>>:
Dear QE Users,

I am working on some modifications to the QE-6.0 code using symmetry. When I try to combine a 3-D array scattered across nodes, I use the following:

output(3,nbnds,(k_pool*pool_id+1:k_pool*pool_id+k_pool))=input(3,nbnds,1:k_pool)

Here, nbnds is the number of bands, k_pool is the number of k points/pool, and pool_id is the id of the pool. Here I am assuming the the number of k points is divisible by the number of pools.

Then I call mp_sum(output,inter_pool_comm) to put all the segments of input across the nodes  into one output file.

When I run the modified QE code in parallel, the output file is different from the serial run.

Does the QE's mp_sum allow the above operation for a three-D array?

Any hints or suggestions would be greatly appreciated.

Vahid

Vahid Askarpour
Department of Physics and Atmospheric Science
Dalhousie University,
Halifax, NS, Canada
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