[Wien] Warning force

[Laurence Marks]

Probably you used an initial cif file with limited accuracy. There is
an (undocumented) piece of code in SRC_pairhess, patchsymm which can
be called via "x patchsymm". It does an average over the symmetry
operations of case.struct producing a new file case.struct_new . Look
at the output (case.outputpatch) and compare the new file which should
have 1/3, 2/3 positions exactly.

For reference, the code probably fails for rhombohedral cells, should
work in other cases and find unsuspected errors in positions.

On 4/5/07, Gilles Hug <gilles.hug at onera.fr> wrote:
>
>
> Le 5 avr. 07 à 20:26, Peter Blaha a écrit :
>
> Dear Gilles,
> You should check your calculation!
>
> The warning is because some components of the force (:FSU or :FVA) are
> nonzero, although they should be zero. mixer then corrects it and FTOT,
> FGL look ok.
>
> Also your optimized struct files is not ok. Look at your positions! They
> should be exactly 1/3 or 2/3 , but they are not ! These wrong
> (inaccurate) positions lead to the force warnings.
>
>
> Dear Peter,
> Thanks I didn't noticed the other coordinates. I try to trace back where
> this behavior comes from but I have not found. It seems already wrong in the
> initial file.
> Gilles
>
>
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>


-- 
Laurence Marks
Department of Materials Science and Engineering
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Northwestern University
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email: L-marks at northwestern dot edu
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