[Pw_forum] phonon calculation for large system

[Huiqun Zhou]

Gabriele,

I just downloaded the CVS version two days ago, but found no INPUT_PH
in Doc. Should you please post one, or let me know how to generate it?

Huiqun Zhou
@Earth Sciences, Nanjing University, China


----- Original Message ----- 
From: "Gabriele Sclauzero" <sclauzer at sissa.it>
To: "PWSCF Forum" <pw_forum at pwscf.org>
Sent: Thursday, April 30, 2009 3:46 PM
Subject: Re: [Pw_forum] phonon calculation for large system


>
>
> zq wu wrote:
>> Dear pwscf users,
>>
>> I need to do phonon calculation for large system (several hundreds atoms
>> per cell). Since i can use lots of processors, I plan to submit many
>> jobs,  each of which will calculate 1 phonon mode. But i do not know
>> whether it is available to get final dynamic matrix from these separate
>> runs and how to do it. Can any one help me?
>>
>>  Currently, phonon modes are calculated one by one in sequence in phonon
>> calculation. Can we do some parallelization here? Can we divide the
>> processors into several groups and let each group take care of one or
>> more modes in a way similar to K-points parallelization?  I think that
>> the parallel efficeincy for modes parallelization should also be close
>> to K-points parallelization since the phonon modes calculation is
>> independent of each other.  The modes parallelization should be very
>> useful for system with large numbers of atoms.  Does anyone have the
>> idea how hard it is to do the modes parallelization?
>
> If I correctly understood, i think that this kind of parallelization has 
> already been
> exploited in the latest versions of CVS, in order to use ph.x on the GRID. 
> I don't know if
> all the related problems have been fixed at this stage (have they, 
> Paolo?), but you can
> try to download the CVS and use the keywords start_q, last_q, start_irr, 
> last_irr (see
> INPUT_PH) to split your job in many independent jobs. Sorry, I don't know 
> the details, but
> at least now you're aware that there is this possibility available (though 
> not extensively
> tested, I think, so use _with_ _care_ and help debugging, please).
>
> HTH
>
> GS
>
>
>>
>> Thanks
>>
>> Zhongqing
>>
>> CACS  University of Southern California
>>
>>
>>
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>>
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> -- 
>
>
> o ------------------------------------------------ o
> | Gabriele Sclauzero, PhD Student                  |
> | c/o:   SISSA & CNR-INFM Democritos,              |
> |        via Beirut 2-4, 34014 Trieste (Italy)     |
> | email: sclauzer at sissa.it                         |
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