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

[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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-- 
Andrea Dal Corso                    Tel. 0039-040-3787428
SISSA, Via Bonomea 265              Fax. 0039-040-3787249
I-34136 Trieste (Italy)             e-mail: dalcorso at sissa.it