[Wannier] Issue with convergence

[Giovanni Pizzi]

Dear Carlo,
from the file you sent, it seems that after getting to 1e-14, the delta 
does not go increase again, but it actually drops to zero.
1e-14 is already extremely tight, and I think that numerically you 
cannot go lower than this due to the finite precision of float numbers.
Note also that the syntax you are using is in practice asking only for a 
s orbital on a single Pb atom, check if this is what you want (I don't 
think that the l=0:l=1 syntax is valid, even if Wannier90 is not 
complaining). Check also that the single band you are considering is 
actually disentangled from the other ones.

Finally, I don't know why the XSF contains NaN, it is difficult to say 
why it happens with the info you provided.

Best,
Giovanni



On 10/06/2015 11:48 AM, Carlo Motta wrote:
> Dear Wannier90 users,
>
> I write to ask for some help.
> I am trying to wannierize the valence band of a perovskite material, I tried with many initial centers but it seems that I am not able to converge the calculation.
> I reach a value of Delta~1E-14 but then it increases and does not converge. I think that in order to have a good result I should reach something on the order of E-20.
>
> However, even if I stop the calculation once the E-14 Delta has been reached (by tuning num_iter), the XSF file contains all NaN, which is worrying me.
>
> Could anyone give me a hint?
>
> Thank you in advance,
>
>
> --
>                
> Carlo Motta
>
> PostDoc Researcher
> School of Physics and CRANN,
> Trinity College Dublin,
> Dublin 2, IRELAND
> http://sites.google.com/site/carlomottaphd
>
>
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-- 
Giovanni Pizzi
Post-doctoral Research Scientist
EPFL STI IMX THEOS
MXC 340 (Bâtiment MXC)
Station 12
CH-1015 Lausanne (Switzerland)
Phone: +41 21 69 31124

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