[Wannier] Format of UNK files

[Hung Pham]

Hello Peyton,

I checked the plot.F90 which is used to generate MLWFs from UNK. There will
be a problem if UNK files from the two calculations have different grid
size and No. of k-point.
The number of bands in UNK (i.e., *nbnd*) and the number of the required
band = No. of MLWFs (i.e., *num_bands*) can be different. Meaning *nbnd* is
not necessarily equal to *num_bands*
The plot.F90 will read the first *num_bands* th band when constructing
MLWFs.
With that being said, I guess in your case, you excluded some upper bands
hence the first *num_bands* th band in both UNK files from two setup are
actually the same. I think if you exclude some core bands then the
generated MLWFs from different setup should be different.

I think if you're not sure which UNK file you have in hand then regenerate
them would be a good idea. Otherwise, you can read the No. of band in UNK
like the script I sent and check (still not 100 % sure which bands you have
in UNK file). But the problem would be two setup with the same No. of bands
(by excluding the same number of different bands) then I don't know how you
can be sure which one should be from which setup.

maybe other people here have a better practice.

Hung

On Tue, Jul 2, 2019 at 6:34 PM Robert Peyton Cline <
Robert.Cline at colorado.edu> wrote:

> Hi Hung,
>
> Ok, thanks for the info and the link.  However, this raises another
> question for me if you have the time.  I have 2 different projection setups
> of the same parent VASP job, and additionally, one of these setups sets the
> exclude_band tag, while the other one does not.  I generated all the
> wannier.* files from the same WAVECAR file using IALGO = 2 in VASP, so all
> the information about the overlaps and the eigenvalues are the same between
> the two setups (except the effect of the exclude_bands tag, of course).  I
> mistakenly mixed up the UNK files between the runs, so I would have guessed
> there should have been some clash with the UNK file format considering I
> either set or did not set exclude_bands.  However, when I got my plotting
> results back, everything appeared to run OK, and my Im/Re ratios were
> good.  So my question is - is there some safety protocol in place that
> ensures this behavior?  I would have figured my jobs would have crashed
> because of the mismatch, but that's not the case.  Any help would be
> appreciated.
>
> Thanks,
> Peyton Cline
>
> On Tue, Jul 2, 2019 at 5:25 PM Hung Pham <phamx494 at umn.edu> wrote:
>
>> Hi,
>>
>> Indeed, the number of bands in UNK file depends on the 'exclude_bands'.
>> I wrote a python function to read the UNK files generated by VASP. It is
>> a part of my MCU code to analyze VASP output and so.
>> But if you are only interested in the UNK file reader then it can be
>> accessed here:
>> https://github.com/hungpham2017/mcu/blob/master/mcu/vasp/utils.py#L108
>>
>> Hung
>>
>>
>> On Tue, Jul 2, 2019 at 6:11 PM Robert Peyton Cline <
>> Robert.Cline at colorado.edu> wrote:
>>
>>> Dear Wannier developers,
>>>
>>> I have a basic question about the format of the UNK* files that I can't
>>> uncover in the source code.  Are the UNK* files written differently
>>> depending on whether the 'exclude_bands' tag is set in the wannier90.win
>>> file?  It would make sense to me if they were, considering the other files
>>> (*amn, *mmn, and *eig) are written without the bands declared by
>>> 'exclude_bands', but I just find get a clear answer anywhere and I can't
>>> check the files themselves since they are written in binary.
>>>
>>> Many thanks,
>>> Peyton Cline
>>> 5th year PhD student
>>> Eaves Group
>>> CU-Boulder
>>> _______________________________________________
>>> Wannier mailing list
>>> Wannier at lists.quantum-espresso.org
>>> https://lists.quantum-espresso.org/mailman/listinfo/wannier
>>>
>>
>>
>> --
>>
>> Hung Q. Pham
>> Gagliardi Group
>> Office: Smith 101
>> Email: phamx494 at umn.edu
>>
>> Department of Chemistry
>> University of Minnesota - Twin Cities, Minneapolis, MN 55455
>>
>

-- 

Hung Q. Pham
Gagliardi Group
Office: Smith 101
Email: phamx494 at umn.edu

Department of Chemistry
University of Minnesota - Twin Cities, Minneapolis, MN 55455
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