[gpaw-users] LCAO basis sets generation

[Ask Hjorth Larsen]

(Re-added list; please reply to list)

2016-03-23 9:40 GMT+01:00 Alexander Romanov <alphard.rm at gmail.com>:
> Thanks for your  reply, Ask.
>
> I have found the source of discrepancy between command line and script
> generation. Command line gpaw-basis has a parameter scalarrel = True as a
> default one. Now I have only little difference in basis sets.
>
> But I still can not use PW91 basis set in my calculation. When I do
> something like this:
>
> calc = GPAW(mode='lcao', basis='dzp', xc='PW91', kpts=(12,12,12,),
> txt=Pt_Lconst.txt)
>
> I get an error:
>
> RuntimeError: Could not find required PAW dataset file "Pt.PW91".
>
> I has no error with other xc (LDA, PBE, RPBE).
>
> So, the question is: can I do calculation with PW91 functional in lcao mode?

You need to generate a PW91 setup.  gpaw-basis does not save it,
although for technical reason it is calculated as part of the
calculation.  So either run gpaw-setup <....> and later gpaw-basis
with corresponding parameters, or write a script which generates both
the setup and its corresponding basis set and saves them.

It has been on my stagnant todo-list for years to do allow to save the
setup file while running gpaw-basis (and many other improvements).

Now *drumroll* there's a merge request which will implement this:

  https://gitlab.com/gpaw/gpaw/merge_requests/27

Then this will be possible:

  gpaw-basis --save-setup <args>

You mentioned that some results were inaccurate.  Could you please elaborate?

Best regards
Ask


>
> Best regards,
> Alex
>
>
> 2016-03-22 17:00 GMT+03:00 Ask Hjorth Larsen <asklarsen at gmail.com>:
>>
>> Dear Александр
>>
>> 2016-03-22 13:05 GMT+01:00 Александр Романов <alphard.rm at gmail.com>:
>> > Hello,
>> >
>> > We've use LCAO mode for fast optimization and met some problems with
>> > basis
>> > sets
>> > for transition metals.
>> >
>> > Default dzp basis sets for Cu, Ag, Pd and Pt give unphysical results for
>> > lattice constant.
>>
>> Which lattice constant do you get then, and which did you expect?
>> Would you please attach the input scripts and logs?
>>
>> > Better convergence of Poisson solver, denser k-points and grid-points
>> > meshes
>> > give no improvement.
>> > We've tried to use gpaw-basis command and manual script for making tzp
>> > sets.
>> > So, we have
>> > two questions:
>> >
>> > 1)If we use command
>> >
>> > gpaw-basis -f PW91 --lpol=1 -t tzp Pt
>> >
>> > we get an error:
>> >
>> > File "/home/user/bin/gpaw-1.0.0/lib/python/gpaw/atom/all_electron.py" .
>> > line
>> > 779. in shoot
>> > dudrplus = 0.5 * (u[gtp + 1] - u[gtp - 1]) / dr[gtp]
>> > IndexError: index out of bounds
>> >
>> > But all works fine for PBE and RPBE functionals or other elements (for
>> > example, Pd).
>> >
>> > 2) If we use manual script, we get basis set twice as large as
>> > gpaw-basis
>> > set. As a consequence we've got
>> > slow calculations.
>>
>> Again, please attach the script.
>>
>> >
>> > How can we resolve problem with gpaw-basis command and what's the
>> > difference
>> > between gpaw-basis
>> > and manual script basis set generation?
>>
>> gpaw-basis is a limited interface.  If you write a Python script to
>> generate the basis, you get much more flexibility.  This may in the
>> end be what you are looking after, if gpaw-basis does not serve.
>>
>> Best regards
>> Ask
>>
>> >
>> > Best regards,
>> >
>> > Alex
>> >
>> >
>> >
>> >
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>
>