[QE-users] I'M STUCK!! Please Help me!! c_bands: N eigenvalues not converged

[Paolo Giannozzi]

On 12/05/2023 10:40, Dipta Suryya Mahanta via users wrote:

> Please ignore the previous attachments, these are the proper 
> attachments.

they aren't any more informative than the previous ones: the output of 
the band calculations is incomplete and no error message is reported.
They aren't any more correct either: ALL data of a band calculation 
should be EXACTLY the same as for the previous scf run, EXCEPT a few 
ones: number of bands, list of k-points, type of calculation, 
convergence threshold.

Note that a band calculations does not take much less time per k-point 
than the scf calculation. You have 75 k-points in the band calculation, 
4 in the scf calculation, expect that the band calculatiopn takes 10 to 
20 times more than the scf one.

Paolo

> Apologies for the inconvenience caused.
> Regards,
> Dipta
> 
> 
> On Thu, May 11, 2023 at 4:13 PM Dipta Suryya Mahanta 
> <p22ph007 at nitm.ac.in <mailto:p22ph007 at nitm.ac.in>> wrote:
> 
>     Hello Everyone,
>     *This has been almost 3 months since I'm stuck at one error only!
>     *With 12 atoms (one unit cell) of FeS2, the bands calculation runs
>     good, but with 96 atoms, it shows the following error EVERYTIME:
>     (1st scf, then bands calculation)
>     bands output:
> 
>     ....
>     Band Structure Calculation
>           Davidson diagonalization with overlap
>           c_bands:  5 eigenvalues not converged
>           c_bands:  4 eigenvalues not converged
>           c_bands:  1 eigenvalues not converged
>           c_bands:  4 eigenvalues not converged
>           ........
>     After this, the program doesn't calculate the band structure even if
>     it shows JOB DONE. The faulty band structure is attached herewith. I
>     have also given all the inputs and output files.
> 
>     KINDLY PLEASE help me or enlighten me to solve this error. I will be
>     greatly indebted to you. Thank you.
> 
>     *Regards,*
>     Dipta S Mahanta
> 
> 
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-- 
Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,
Univ. Udine, via delle Scienze 206, 33100 Udine Italy, +39-0432-558216