I agree with Ricardo, you need a convergence of total energy (or the property you want to analyze)... this comment I told you by email some day ago....!!!<br><br> PhD std. Arles V. Gil Rebaza<br> Instituto de Física de La Plata<br>
La Plata - Argentina<br><div class="gmail_quote"><br><br>2011/5/12 Ricardo Faccio <span dir="ltr"><<a href="mailto:rfaccio@fq.edu.uy">rfaccio@fq.edu.uy</a>></span><br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
Hi<br>
The number of k points is always chosen in terms of convergence of some<br>
physical property, this is the final decision. Dependent of the metallic<br>
nature of your case, you may choose high or lower number of k-points.<br>
In the case of codes with not so efficient methods for Brillouin Zone<br>
integration, e.g. SIESTA, you need to use a considerable amount of<br>
k-points in order to reach convergence.<br>
But in QE, you can get the best choice, going step by step, increase<br>
little by little, the number of k-pints, until reaching convergence.<br>
Certainly, you will get a number considerably lower than 100.<br>
Additionally, H-saturated zigzag nanoribbons are insulators -<br>
antiferromagnets, so maybe you will need few kpoints.<br>
Regards<br>
Ricardo<br>
<div><div></div><div class="h5"><br>
> Hi Arles,<br>
><br>
> Sorry, I realized the same, the reason I chose 1 1 100 was, I was using<br>
> another quantum software and the forum there had displayed results with<br>
> having the k points as 100, so to be in better position to be able to<br>
> compare with their result I chose 100, but as you have pointed out and I<br>
> learned myself, the decision was indeed insane. I am still trying to learn<br>
> how specifically can one decide on k points, do you have any suggestion on<br>
> k<br>
> points for my input file,<br>
><br>
> On Thu, May 12, 2011 at 10:11 AM, Arles V. Gil Rebaza<br>
> <<a href="mailto:arvifis@gmail.com">arvifis@gmail.com</a>>wrote:<br>
><br>
>> Why do you choose 1 1 100 k-points.... this is an insane<br>
>> desicion....!!!!!!<br>
>><br>
>> PhD std. Arles V. Gil Rebaza<br>
>> Instituto de Física de La Plata<br>
>> La Plata - Argentina<br>
>><br>
>><br>
>><br>
>><br>
>><br>
>> 2011/5/12 swapnil chandratre <<a href="mailto:swapnil.chandratre@gmail.com">swapnil.chandratre@gmail.com</a>><br>
>><br>
>>> Hi,<br>
>>><br>
>>> Thank you for sparing time on this, I will try to get it resolved<br>
>>> sooner.<br>
>>> Any suggestions are heartily welcomed.<br>
>>><br>
>>><br>
>>> On Thu, May 12, 2011 at 9:03 AM, Paolo Giannozzi<br>
>>> <<a href="mailto:giannozz@democritos.it">giannozz@democritos.it</a>>wrote:<br>
>>><br>
>>>><br>
>>>> On May 12, 2011, at 15:49 , swapnil chandratre wrote:<br>
>>>><br>
>>>> > I just wanted to know if there is no error with the script<br>
>>>><br>
>>>> I don't know if there is an error in the script. I just tried to<br>
>>>> run it on a PC, it starts but it is definitely too large for a<br>
>>>> single CPU. Since the code writes > 800Mb Kohn-Sham<br>
>>>> wavefunctions for each of the 100 k-points, insufficient disk<br>
>>>> space looks like a promising explanation<br>
>>>><br>
>>>> P.<br>
>>>> ---<br>
>>>> Paolo Giannozzi, Dept of Chemistry&Physics&Environment,<br>
>>>> Univ. Udine, via delle Scienze 208, 33100 Udine, Italy<br>
>>>> Phone +39-0432-558216, fax +39-0432-558222<br>
>>>><br>
>>>><br>
>>>><br>
>>>><br>
>>>> _______________________________________________<br>
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>>>><br>
>>><br>
>>><br>
>>><br>
>>> --<br>
>>> Regards,<br>
>>> Swapnil Chandratre<br>
>>> Graduate Student<br>
>>> Dept. of Mechanical Engineering,<br>
>>> University of Houston,<br>
>>> Houston, TX<br>
>>> (M)-713-294-9546<br>
>>><br>
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>>><br>
>>><br>
>><br>
>><br>
>> --<br>
>> ###---------> Arles V. <---------###<br>
>><br>
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>><br>
>><br>
><br>
><br>
> --<br>
> Regards,<br>
> Swapnil Chandratre<br>
> Graduate Student<br>
> Dept. of Mechanical Engineering,<br>
> University of Houston,<br>
> Houston, TX<br>
> (M)-713-294-9546<br>
> _______________________________________________<br>
> Pw_forum mailing list<br>
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><br>
<br>
<br>
--<br>
</div></div>-------------------------------------------------<br>
Dr. Ricardo Faccio<br>
Prof. Adjunto de Física<br>
Mail: Cryssmat-Lab., Cátedra de Física, DETEMA<br>
Facultad de Química, Universidad de la República<br>
Av. Gral. Flores 2124, C.C. 1157<br>
C.P. 11800, Montevideo, Uruguay.<br>
E-mail: <a href="mailto:rfaccio@fq.edu.uy">rfaccio@fq.edu.uy</a><br>
Phone: 598 2 924 98 59<br>
598 2 929 06 48<br>
Fax: 598 2 9241906<br>
Web: <a href="http://cryssmat.fq.edu.uy/ricardo/ricardo.htm" target="_blank">http://cryssmat.fq.edu.uy/ricardo/ricardo.htm</a><span onmouseout="cancel = false; window.setTimeout(WRCHideContent, 1000);" onmouseover="WRCShowContent({'rating':{'value':-1,'weight':-1},'flags':{},'ttl':3600,'expireTime':'20110512135544'}, this.className);" class="wrc0" style="padding-right: 16px; width: 16px; height: 16px;"></span><br>
<div><div></div><div class="h5"><br>
<br>
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</div></div></blockquote></div><br><br clear="all"><br>-- <br>###---------> Arles V. <---------###<br>