[gpaw-users] Computational cost of vdW-DF

[Duy Le]

2011/4/12 Jens Jørgen Mortensen <jensj at fysik.dtu.dk>:
> On Mon, 2011-04-11 at 23:56 +0200, Duy Le wrote:
>> Dear all,
>> As I understand, the approach of Román-Pérez and Soler (PRL 2009) has
>> been implemented in GPAW.  I wonder why the self-consistent vdW-DF
>> calculation is still extremely expensive (3 or 4 times in most of my
>> calculations) in comparison to regular GGA-PBE calculation.
>> Does any of you experience this slowness? I would like to know the reason.
>
> For a small system with few electrons, the calculation of the vdW-DF
> potential will dominate.  With more electrons the vdW-DF part should
> become smaller unless you run on so many cores that the parallelization
> of the vdW-DF stuff stops scaling.  So, what is your system and how many
> cpu's do you use?
It is the case, my systems are big, in the order of about 70-150
atoms. Of course I have to use lot of cores (64 to 512 cores in most
of the case) otherwise I don't have enough memory allocated.
Is there any way to improve it? The PBE calculation is scaled very well.
>
> Jens Jørgen
>

--------------------------------------------------
Duy Le
PhD Student
Department of Physics
University of Central Florida.

"Men don't need hand to do things"
>> Thank you.
>> --------------------------------------------------
>> Duy Le
>> PhD Student
>> Department of Physics
>> University of Central Florida.
>>
>> "Men don't need hand to do things"
>>
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>
>