[QE-users] nscf calculation of 2x2x2 Si supercell

[Stefano Baroni]

PS. Start practicing with a small unit cell that you can draw with your hands. Get familiar with the numerical parameters (thresholds, cutoffs, etc.) in that case and develop your feeling on what happens when you change each of them. Starting with examples provided with the distribution may be a good idea. Then, but only then, try more complex (and possibly meaningful) cases. Above all, do not do anything that you do not understand, no matter who recommends that. Good luck! SB

> On 14 May 2020, at 17:32, Stefano Baroni <baroni at sissa.it> wrote:
> 
> Fariba: luck is no substitute for practice & understanding.
> 
>> On 14 May 2020, at 16:34, Fariba Islam <ezqhaz at gmail.com <mailto:ezqhaz at gmail.com>> wrote:
>> 
>> Initially it was 1e-8 but nscf calculation was crashing. So I searched for a solution and in ResearchGate I found that in order to solve this I need to decrease conv threshold or increase ecutwfc. That is why I increased it to such high values gradually. But didn’t have any luck.
>> 
>> On Thursday, May 14, 2020, Stefano de Gironcoli <degironc at sissa.it <mailto:degironc at sissa.it>> wrote:
>> do you really need conv_thr=1e-20 ?
>> 
>> stefano
>> 
>> On 14/05/20 09:18, Fariba Islam wrote:
>>> Dear all,
>>> My  conv_thr=1e-20 and ecutwfc=200 ecutrho=800
>>> My nscf calculation is crashing with the error 
>>> 
>>> task #        10
>>>      from c_bands : error #         1
>>>      too many bands are not converged
>>> 
>>> How can I solve? From suggestions found online, I have reduced the threshold and increased ecutwfc and ecutrho. 
>>> Regards
>>> Fariba Islam
>>> Bangladesh University of Engineering and Technology
>>> 
>>> 
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> — 
> Stefano Baroni - Trieste —  http://stefano.baroni.me <http://stefano.baroni.me/> 
> 
> 
> 
> 
> _______________________________________________
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— 
Stefano Baroni - Trieste —  http://stefano.baroni.me <http://stefano.baroni.me/> 




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