[Wien] 1000 atom fix

[Peter Blaha]

At present WIEN2k is restricted to 999 non-equivalent atoms.

The calculations I mentioned had inversion symmetry, i.e. about
700 non-equivalent atoms, but 1400 atoms/cell.

Maybe you can start your structure by modifying the struct file
(by hand or some script) and put atoms with the same Z together
as "equivalent" atoms (eg. using MULT=48).
Such a struct file can have more atoms and eventually sgroup or nn
can rewrite a valid struct file with some symmetry (some equivalent 
atoms).   If there is NO symmetry, then WIEN2k is limited to 999 atoms.

Alternatively, just changing nn.f so that it can read more than 1000 
atoms is fairly trivial (modification of FORMATS 1511, 1012 and probably 
a few more where "I3" is used.)

PS: I hope you are aware, that such calculations need a parallel 
computer with 64-100 cores, infiniband and >50GB memory!


Oleg Rubel schrieb:
> Dear Wien2k Users and Developers,
> 
> I model antiphase boundary structure in III-V semiconductors. The raw structure I prepared has 1200 atoms and is not optimal from the symmetry point of view. I expect "x sgroup" to generate an optimal structure. The generated structure has 200 atoms, which does not surprise me, but when I look at the structure I see that there are missing atoms. (Everything was fine with 768 atom structure, which was brought by sgroup down to 48 independent atoms.) It seems that the number of atoms is limited to 999, at least by sgroup.
> 
> I remember that at one of Wien2k workshops Peter spoke about >1000 atoms simulation. I wonder if there is a special patch to unable >1000 atoms?
> 
> Thank you in advance.
> 
> Sincerely,
> Oleg
> 
> --
> Oleg Rubel, PhD
> Scientist
> Thunder Bay Regional Research Institute
> 290 Munro St
> Thunder Bay, ON
> P7A  7T1, Canada
> Phone: +1-807-7663350
> Fax: +1-807-3441948
> E-mail: rubelo at tbh.net
> Homepage: http://www.tbrri.com/~orubel/
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