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

[Paolo Giannozzi]

On 5/15/23 13:20, Dipta Suryya Mahanta wrote:

> the attachments in the second mail are of 96 atoms in which the error is 
> there in the 'fes2.bands.out' file.

1. there is no error in fes2.bands.out: the messages
    "c_bands:  3 eigenvalues not converged"
    are not necessarily a sign of error

2. the cutoffs in fes2.scf.in and fes2.bands.in differ

Paolo

> 
> On Sat, May 13, 2023 at 1:40 PM Paolo Giannozzi 
> <paolo.giannozzi at uniud.it <mailto:paolo.giannozzi at uniud.it>> wrote:
> 
>     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>
>     <mailto: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
> 

-- 
Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,
Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
Phone +39-0432-558216, fax +39-0432-558222