[Pw_forum] CO/Cu(100) phonon calculation problem.

[Alcantara Ortigoza, Marisol]

Paolo Giannozzi wrote:

>if one restarts from a run that was stopped because of cpu 
>time limit or machine crash or whatever unexpected reason, 
>the probability that something goes wrong (i.e. that files are 
>corrupted) is very high. If however the run is cleanly stopped, 
>i.e. by the code itself and not by external factors, one should 
>be able to restart without any problem. It is however prudent 
>to save a copy of the temporary files before restarting a new 
>job.

>It is hard to say what happened in this specific case, since it 
>is not clear whether the problem occurs due to restarting or
independently of it. In the >former case, it should be possible 
>to find cases in which the restart reproducibly fails.

Then, it is clear to me that the problem was not because of restarting
issues. First, the run stopped  cleanly. At the end the last 'correct'
output file shows "Stopping for time limit     13699.    13400.". 

Second, the next run - where the problem arose - started properly. It
still performed two iterations without any problem. Therefore, it
couldn't be a restarting problem. What then? Is it possible to recover
anything?

Thanks. Marisol.

-----Original Message-----
From: pw_forum-admin at pwscf.org [mailto:pw_forum-admin at pwscf.org] On
Behalf Of Paolo Giannozzi
Sent: Wednesday, August 24, 2005 7:46 AM
To: pw_forum at pwscf.org
Subject: Re: [Pw_forum] CO/Cu(100) phonon calculation problem.


On Tuesday 23 August 2005 21:25, Eyvaz Isaev wrote:

> Sorry for interfiering. Presumably Paolo has some
> strong arguments against my suggetion, but in my
> experience phonon calculations were never succesfull
> from restart.

if one restarts from a run that was stopped because of cpu 
time limit or machine crash or whatever unexpected reason, 
the probability that something goes wrong (i.e. that files are 
corrupted) is very high. If however the run is cleanly stopped, 
i.e. by the code itself and not by external factors, one should 
be able to restart without any problem. It is however prudent 
to save a copy of the temporary files before restarting a new 
job.

It is hard to say what happened in this specific case, since it 
is not clear whether the problem occurs due to restarting or
independently of it. In the former case, it should be possible 
to find cases in which the restart reproducibly fails.

Paolo

-- 
Paolo Giannozzi             e-mail:  giannozz at nest.sns.it
Scuola Normale Superiore    Phone:   +39/050-509876, Fax:-563513 
Piazza dei Cavalieri 7      I-56126 Pisa, Italy
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