[Pw_forum] problem with TPSS (Tao-Perdew-Staroverov-Scuseria) meta-GGA for silicon

[Axel Kohlmeyer]

rafael,

please keep in mind, that a single atom in a large box
is a bit of a pathological case, since you tend to pick up
all the noise from the "vacuum" area, which is most likely
the source of your numerical instabilities. if it is just for
testing, you'll probably get better results with a bulk crystal
system (and it'll be faster, too).

cheers,
   axel.

On 11/27/08, Rafael Dias Menezes <rdmeneze at yahoo.com.br> wrote:
> On Nov 23, 2008 at 22:04 , Paolo Giannozzi wrote:
>
>>TPSS is quite nasty from a numerical point of view. Try to use lapack
>>from sources instead of optimized libraries. On my Macintosh I get
>>this problem when testing tests/metaGGA.in with atlas loaded;
>>it disappears if I link lapack instead.
>
> Thank you, Paolo for the trick.
>
> Really this error disappear but the calculation to silicon atom in a big box
> don't converge. I did 100 interactions and the convergency isn't reach.
>
> Can someone get me a direction in this simple calculus? Maybe I'm missing
> the setup of some input variable do pwscf.
>
> thanks,
> Rafael Dias
>
>
>
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Axel Kohlmeyer   akohlmey at cmm.chem.upenn.edu   http://www.cmm.upenn.edu
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