[ase-users] Jacapo convergence issues

[John Kitchin]

This sounds like there could be a problem with the pseudopotential of Ru. I
vaguely recall Ru calculations going slowly. You may see if there are other
psp available for Ru. maybe one with fewer valence electrons. An indicator
something is wrong is if there are large forces on your atoms with a GPAW
optimized geometry. That sounds incorrect. I would expect some forces, but
not large ones.

I am not too surprised the files are large; you have a big system and a
large unit cell, and a whole lot of bands. Dacapo does not parallelize
well. It is pretty good over kpoints, and not very good over planewaves, so
parallelization is unlikely to speed up things as much as you would hope if
you are using small kpt grids.

Calculations in Jacapo should automatically start at the last position in
the ncfile.


On Thu, Jan 24, 2013 at 6:33 AM, Niels Theis Bendtsen <ntben at fysik.dtu.dk>wrote:

> Hi ASE user and John Kitchin (I was told to cc to you by Marcin Dulak as
> you were the most experienced Jacapo user)
>
> I hope at least one you can help me. I am normally using GPAW but I have
> been trying to verify my results with Jacapo in which I am very new. The
> issue is that the calculations are very hard to converge and so far I only
> managed to converge a few. On top that the are very slow at least compared
> to GPAW.
>
> So the system is a four layer slab of 3x2 super cell of RuO2 with doped Ni
> and different adsorbates on top. And they are spin polarized. I use the
> optimized structures from GPAW using the .traj file to get the atomic
> positions and magnetic moments etc. I have attached a script and the
> submission shell script and the associated txt output.
>
> The pw and dw values I have taken from similar (older) calculation on a
> 2x2 RuO2 slab.
>
>
> In the time allocated it only manages to do two geometry optimization step
> in 45 hours on 48 cores on niflheim.
>
> Any tips on improving convergence or speed? Is it possible to restart the
> calculation from where it has ended?
>
> I do know that my kpoint sampling might be a bit odd but it is converged
> at least with GPAW.
>
> Also the associated .nc files are huge...
>
> I hope I am doing some awfully wrong so that it can be fixed.
>
> Sincerely
> Niels Theis Bendtsen
> Ph.d.-studerende
> FYS-CAMD
> DTU Fysik
> Bygning 307
> 2800 Kgs. Lyngby
> Direkte telefon 45253177
> ntben at fysik.dtu.dk
> www.fysik.dtu.dk
>
>
>
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