[Pw_forum] parallel computation too slow

[Axel Kohlmeyer]

On Mon, Mar 19, 2012 at 9:45 AM, Elie M <elie.moujaes at hotmail.co.uk> wrote:
> Professor Giannozzi,
>
> Thanks for the reply. The CPU time is 1 hr 26 min (2hrs 2 min normal time)
> for the scf calculation on the nodes (3 of them). If I have 42 atoms then
> this is equivalent to almost 8 days CPU time or 10 days normal time. Four
> days have passed and I am still in representation 6 out of 126 which i guess
> is not the normal situation...Can anything be done  (or checked) in this
> case?

get a real computer! if you already lose a quarter of the time due to
swapping for the scf calculation, you'll be seriously out of memory
for anything more advanced. your laptop is obviously not suitable
to carry out this kind of calculation. sorry.

axel.

>
> Regards
>
>
> Elie
>
>> CC: pw_forum at pwscf.org
>> From: giannozz at democritos.it
>> Subject: Re: [Pw_forum] parallel computation too slow
>> Date: Fri, 16 Mar 2012 21:48:15 +0100
>> To: elie.moujaes at hotmail.co.uk
>
>>
>>
>> On Mar 16, 2012, at 19:14 , Elie M wrote:
>>
>> > I am running phonon calculations for a supercell of 60 atoms at the
>> > gamma point [...]
>> > What could the possible causes of this slowness be? Is it something
>> > to do with the
>> > nodes or with phonon calculations in general? Is there a way to check?
>>
>> >
>>
>> a phonon calculation for N atoms requires a CPU time of the order of
>> 3N the time of
>> the correspoding scf calculation. Does yours? if it does, there is
>> nothing that can be
>> done.
>>
>> P.
>> ---
>> Paolo Giannozzi, Dept of Chemistry&Physics&Environment,
>> Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
>> Phone +39-0432-558216, fax +39-0432-558222
>>
>>
>>
>>
>
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-- 
Dr. Axel Kohlmeyer
akohlmey at gmail.com  http://goo.gl/1wk0

College of Science and Technology
Temple University, Philadelphia PA, USA.