[Wien] Supercell calculation dilemma with WIEN2k_12

[Laurence Marks]

For a system like this you need to be using mpi. Depending upon how
patient you are and the cores available to you somewhere in the range
of 16-64 cores. You will never get anywhere otherwise.

On Wed, May 29, 2013 at 6:00 PM, Guo-ping Zhang
<gpzhang at femto.indstate.edu> wrote:
> Dear Peter and Wien2k users,
>
> (Many thanks for your help for my previous questions!)
>
> I was trying to do a supercell calculation (60 atoms) within 28x28x28
> (Angstrom^3), half of which is vacuum. Here are some of the questions that
> I have. (To be sure, I have searched all the previous 110 emails on this
> topic, but failed to notice any solutions to this, except a nice comment
> on the formation energy by Dr. Stefaan Cottenier.)
>
> (1) Problems with the new WIEN2k.
>
> "x lapw0" complains the insufficient memory like this,
>
> forrtl: severe (41): insufficient virtual memory
>
> This does not happen in the old wien. So my question is whether I can
> change some parameters in SRC_lapw0, so at least x lapw0 runs.
>
> (2) Problems with the old WIEN2k.
>
> Since the new version does not work, I tried to use the older version,
> which worked well, but there is a problem with RKM. Due to the limit set
> by NMATMAX (=10000), the RKM is now truncated to 3.24. To test the vacuum
> thickness effect, I have to increase the thickness, but this further
> reduces RKM to  an even smaller value. Since I am mostly interested in
> unoccupied states several eV above Ef, this casts
> doubts on the wien results. (After I compared it with Gaussian results,
> I found that APW calculation gives wrong symmetry splitting in those
> unoccupied states, but LAPW is ok).
>
> I really appreciate it if you could give me some suggestions how to get
> the results accurately for such a big system.
>
> If you need additional information,
>
> Many thanks in advance!
>
> Best regards,
> Guoping
>
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-- 
Professor Laurence Marks
Department of Materials Science and Engineering
Northwestern University
www.numis.northwestern.edu 1-847-491-3996
"Research is to see what everybody else has seen, and to think what
nobody else has thought"
Albert Szent-Gyorgi