[Pw_forum] Two problems with ph.x and nimage option

[Florian Altvater]

Hi,
thanks for your help! I assumed that it would be working in 5.0.0 as it
is mentioned in the documentation. But good to know! I'll switch to a
newer version then.

Thanks again,
Flo


Am 08.10.2014 um 01:11 schrieb Andrea Dal Corso:
> On Tue, 2014-10-07 at 15:29 -0700, Florian Altvater wrote:
>> Hi,
>> I am using QE 5.0.0 and am trying to do phonon calculations on the
>> naphthalene crystal with the nimage option. I encounter two different
>> problems:
>>
>> 1) When I use a k-point grid of 2x3x2 for the scf calculation I run the
>> following commands:
>>
>>     aprun -n 192 pw.x -nimage 1 -npool 8 < scf.in <http://scf.in> > scf.out
>>     aprun -n 1728 ph.x -nimage 9 -npool 8 < phG.in > phG.out
>>     aprun -n 192 ph.x -nimage 1 -npool 8 < phGc.in > phGc.out
>>
>> phGc.in is the same file as phG.in with the additional parameter
>> recover=.true.
>> Looking at the output files (phG.out and out.[1-8]_0), everything seems
>> fine. When I run the second phonon calculation to finish up, it ony
>> recognizes that the first 11 modes have been done (they are in phG.out),
>> but states for the other irreps "to be done". It then starts calculating
>> the modes starting with representation 12 but then crashes with a davcio
>> error. Apparently the davcio error could be related to a lot of things.
>> But why doesn't ph.x recognize that all the irreps have already been
>> calculated?
> Please update to QE 5.1, version 5.0.0 is no more supported. As a
> minimum it has to be updated to 5.0.3 to use images. The image
> parallelization was very experimental in QE 5.0.0. It seems that the
> files produced by the different images were not copied in the
> tmp_dir/_ph0/{prefix}.phsave directory. Please also check that the
> Image_example is working in your machine before running a big job.
>
> HTH,
>
> Andrea
>
>
>> 2) Using a k-point grid of 3x4x3 for the scf calculation I run the same
>> commands but use -npool 19 and 456 and 4104 cores respectively. This
>> time the calculation already crashes during the first phonon
>> calculation, just a few seconds after the first image is done
>> (representations 1-11). It spits out lots of errors like:
>>
>> PGFIO-F-204/CLOSE/unit=20/illegal use of a read-only file.
>>  File name = ./naph_crys.wfc6    unformatted, direct access   record = 1
>>  In source file close_phq.f90, at line number 38
>>
>> I couldn't find anything related to this error. Any ideas? Which input
>> files or other information would you need in order to debug?
>>
>> On another machine, running the 2x3x2 calculation on just one image
>> works just fine. I just would like to speed up the calculation using the
>> image method.
>>
>> Thanks for your help,
>> Florian
>>
>> --
>> PhD candidate
>> UC Berkeley/LBNL
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