[Pw_forum] Fwd: Final iteration often crashes after structure optimization

[Paolo Giannozzi]

Actually with the default value of "ecutrho" (4*ecutwfc, suitable for
norm-conserving PPs) it seems to work.

Paolo

On Mon, Aug 10, 2015 at 2:01 PM, Cohen, Ronald <rcohen at carnegiescience.edu>
wrote:

> Lowering ecutrho makes things worse not better. But I understand the
> problem better. It is a problem with load balancing. This problem only
> arises when R & G space division>1 . With R & G space division=1 it never
> crashes in this way. However, the performance with R & G space division=4
> is astounding compared with R & G space division=1. I have 16 k-points, yet
> with npool=16 it takes 74 seconds for the first k-point, and with nppol=4
> on 16 processors (R & G space division=4) it takes 16 seconds--a speedup of
> 4.6 with the same number of processors! Yet 20% of the time or so R & G
> space division>1 fails, presumably because of a load balancing problem. The
> solution is to rebalance the R & G space divisions. Is there a developer
> out there familiar with this?
>
> Sincerely,
>
> Ron
>
>
> ---
> Ronald Cohen
> Geophysical Laboratory
> Carnegie Institution
> 5251 Broad Branch Rd., N.W.
> Washington, D.C. 20015
> rcohen at carnegiescience.edu
> office: 202-478-8937
> skype: ronaldcohen
> https://twitter.com/recohen3
> https://www.linkedin.com/profile/view?id=163327727
>
> On Mon, Aug 10, 2015 at 6:15 AM, Youssef <aharbil at gmail.com> wrote:
>
>> Dear Ronald,
>>
>> Strange behavior, it happens here (ggen.f90)  :
>>
>>  IF (ngm > ngm_g) CALL errore ('ggen', 'too many g-vectors', ngm)
>>
>> I am not QE developer, but firstly I suggest to lower ecutrho to 280 Ry
>> and see!!!
>>
>> Youssef Aharbil,
>> Laboratory of Physics and Chemistry of Materials
>> Faculty of sciences Ben msik, Casablanca
>> Morocco
>>
>>
>>
>
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>



-- 
Paolo Giannozzi, Dept. Chemistry&Physics&Environment,
Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
Phone +39-0432-558216, fax +39-0432-558222
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