[Pw_forum] Problems with interrupted electron-phonon coupling calculation

[Sridhar Sadasivam]

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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