[Pw_forum] Problems with interrupted electron-phonon coupling calculation

[Sridhar Sadasivam]

I just thought I will restate my question, in case it wasn't clear last
time. In the case of a phonon only calculation at a particular q point, it
is possible to run the phonon calculation for different irreps separately
and then copy the data-file.q.irr.xml files into a common place and then
run the phonon calculation again after setting recover = .true., to obtain
the dynamical matrix for that q point. This is essentially grid
parallelization.

I need do this for an electron-phonon calculation. Could someone help me
with what output files that I have to copy from the runs on different
irreps so that I can get the correct electron-phonon coupling results when
I run all irreps together after setting recover = .true.?

Thank you and I would really appreciate any help.
Sridhar
Graduate Student
Purdue University


On Fri, Mar 7, 2014 at 1:45 PM, Sridhar Sadasivam <sridhu88 at gmail.com>wrote:

> I am using espresso 5.0.3. Thanks,
> Sridhar
>
>
> On Fri, Mar 7, 2014 at 1:30 PM, Paolo Giannozzi <paolo.giannozzi at uniud.it>wrote:
>
>> Code version? P.
>>
>> On Thu, 2014-03-06 at 23:36 +0530, Sridhar Sadasivam wrote:
>> > Hello,
>> >
>> >
>> > I am working on an electron-phonon coupling calculation of a large
>> > system (30 atoms). At each q-point I will have 30 x 3 = 90 irreducible
>> > representations. This will take a lot of computer time and I expect
>> > that my calculation will be interrupted (due to max wall time
>> > limitations in the computing cluster I use). So I will need to restart
>> > the calculation many times.
>> >
>> >
>> > To test if everything runs fine, I tried to run an electron-phonon
>> > coupling calculation on a simple 1 atom system. For a particular
>> > q-point I had 2 irreducible representations and I interrupted my
>> > calculation after the self-consistent calculation for the 1st
>> > representation. I then restarted the calculation setting "recover
>> > = .true.". The calculation starts with the 2nd representation and
>> > seems to complete, but the electron-phonon linewidths are wrong, i.e.,
>> > the results don't match the results I get when I run without any
>> > interruption. The phonon frequencies are correct in the interrupted
>> > calculation but the electron-phonon results are not. For some reason,
>> > restarting an interrupted ph.x calculation does not give the correct
>> > results for electron-phonon coupling.
>> >
>> >
>> > Does anyone know how I can resolve this issue? This is crucial as I
>> > will not be able to run the large system (30 atoms) without having to
>> > restart many times.
>> >
>> >
>> > I would really appreciate if someone could help me out on this. Please
>> > let me know if my question isn't clear and I can attach output files
>> > as well.
>> > Regards,
>> > Sridhar
>> > Purdue University,
>> > USA
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> > _______________________________________________
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>> > Pw_forum at pwscf.org
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>>
>> --
>>  Paolo Giannozzi, Dept. Chemistry&Physics&Environment,
>>  Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
>>  Phone +39-0432-558216, fax +39-0432-558222
>>
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>
>
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