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

[Ye Luo]

Hi Vahid,
segfault in mp_sum doesn't necessarily mean a problem there. Probably you
wrote something to output array but not in a valid place before mp_sum.
Try to check your allocation of output and the copy make sure they are
correct.

Ye


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

2016-10-28 14:33 GMT-05:00 Vahid Askarpour <vh261281 at dal.ca>:

> 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> 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>:
>
>> 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))=inp
>> ut(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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>
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