[Pw_forum] ph.x taking a lot of time to run!

[lfhuang]

Dear Elie Moujaes:
    The time cost for the calculation of dynamical matrix in your case is reasonable. Because DFPT needs to solve the perturbation KS equation iteratively for each reciprocal vector. In addition, why did not you specify the value of nq3 to be 1? Graphene is a monolayer of carbon atoms, nq3=1 is enough. 
    To obtain decent phonon dispersion, maybe denser q grid be needed. And to calculate some thermodynamic functions accurately, maybe q grid denser than 9*9*1 is needed. May these be somewhat helpful.
Best Wishes!
Yours Sincerely
L. F. Huang 

> From: Elie Moujaes 
> Subject: [Pw_forum] ph.x taking a  lot of time to run!
> To: 
> Message-ID: 
> Content-Type: text/plain; charset="iso-8859-1"
> 
> 
> Dear PWSCF users,
> 
>  
> 
> Hope you all had a happy Easter. I am running the ph.x code for graphene(and Thankfully no errors are encountered). it is just that it IS taking a really long time to produce the dynamical matrices on the q grid I specified which is:
> 
>  
> 
> nq1= 2, nq2=2, nq3=2 (a total of 8 points).. It is taking like an our to produce the .dyn files for every q point. I do not think it should require that much time. Is there something I might be missing?  
> 
> Thank you
> 
> Elie Moujaes
> 
> University of Nottingham
> 
> NG7 2RD
> 
> UK
 		 	   		  

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L.F.Huang(黄良锋) DFT and phonon physics
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Add: Research Laboratory for Computational Materials Sciences,
Instutue of Solid State Physics,the Chinese Academy of Sciences,
P.O.Box 1129, Hefei 230031, P.R.China
Tel: 86-551-5591464-328(office)
Fax: 86-551-5591434
Web: http://theory.issp.ac.cn (website of our theory group)
http://www.issp.ac.cn    (website of our institute)
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