[Pw_forum] Fw: relax is too slow

[Stefano Baroni]

the same way as you would choose any other parameter controlling the  
accuracy of a numerical calculation. try a value; try a few others  
corresponding to increasing accuracy, and stop when you see that the  
increase in the accuracy is not worth the extra workload. never forget  
to use common sense (whenever it is available).

SB

On Sep 12, 2008, at 11:36 AM, vega wrote:

> Dear sir
>> vega wrote:
>>
>>> As far as I tested, the energy would be within 1% for large  
>>> supercells,
>>> but the coordinates of several atoms may differ 200%.
>>
>> doesn't make sense
>
> could you tell me more about how to choose the k point mesh?
>
> vega
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> ======================================================================
> Vega Lew (weijia liu)
> PH.D Candidate in Chemical Engineering
> State Key Laboratory of Materials-oriented Chemical Engineering
> College of Chemistry and Chemical Engineering
> Nanjing University of Technology, 210009, Nanjing, Jiangsu, China
>
> --------------------------------------------------
> From: "Paolo Giannozzi" <giannozz at democritos.it>
> Sent: Friday, September 12, 2008 5:27 PM
> To: "PWSCF Forum" <pw_forum at pwscf.org>
> Subject: Re: [Pw_forum] Fw: relax is too slow
>
>
>> -- 
>> Paolo Giannozzi, Democritos and University of Udine, Italy
>> _______________________________________________
>> Pw_forum mailing list
>> Pw_forum at pwscf.org
>> http://www.democritos.it/mailman/listinfo/pw_forum
>>
> _______________________________________________
> Pw_forum mailing list
> Pw_forum at pwscf.org
> http://www.democritos.it/mailman/listinfo/pw_forum

---
Stefano Baroni - SISSA  &  DEMOCRITOS National Simulation Center -  
Trieste
http://www.sissa.it/~baroni / [+39] 040 3787 406 (tel) -528 (fax) /  
stefanobaroni (skype)

La morale est une logique de l'action comme la logique est une morale  
de la pensée - Jean Piaget

Please, if possible, don't  send me MS Word or PowerPoint attachments
Why? See:  http://www.gnu.org/philosophy/no-word-attachments.html






-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://www.democritos.it/pipermail/pw_forum/attachments/20080913/cfb996b3/attachment.htm