[gpaw-users] Efficiency of LCAO vs. FD

[Miguel Caro]

Hi Ask,

Thanks a lot, much appreciated.

Miguel


On 2016-11-01 15:31, Ask Hjorth Larsen wrote:
> Hi Miguel
>
> There is a (not fully systematic) benchmark of LCAO production
> calculations for nanoparticles in my thesis, see page 32 and
> thereabouts:
>
>   http://dcwww.camd.dtu.dk/~askhl/files/askhl-thesis-cc.pdf
>   (This version of the thesis is stripped of publications that may
> suffer copyright restrictions and may be freely distributed)
>
> Note the kink at at n=50 atoms where scalapack is switched on and you
> will immediately see its importance.  With good network it will scale
> to more nodes, although that was not the case on our old cluster.
>
> Both hardware and software have improved significantly since.  Many
> parts have been optimized although ScaLAPACK itself has not changed
> much, and that will be the bottleneck for large systems still.
>
> Unfortunately I don't have a good comparison to FD mode.  It is
> difficult to do a general comparison to FD because the performance
> differs widely depending on the type and size of system.  LCAO has the
> greatest advantage for large systems.  It have typically seen large
> and large-ish systems where LCAO was more than an order of magnitude
> faster, but probably not two orders of magnitude.
>
> Best regards
> Ask
>
> 2016-11-01 13:41 GMT+01:00 Miguel Caro via gpaw-users
> <gpaw-users at listserv.fysik.dtu.dk>:
>> Hi all,
>>
>> I was wondering if there is any (more or less) comprehensive comparison
>> between the performance of LCAO mode versus finite-difference mode, and
>> perhaps the effect of different parallel options on performance (e.g.
>> ScaLAPACK). I am thinking for example about a graph where CPU timings for
>> LCAO and FD are plotted together as a function of system size. I would be
>> very grateful if you could point me towards this kind of resource.
>>
>> Many thanks,
>> Miguel
>> --
>> Dr. Miguel Caro
>> Postdoctoral researcher
>> Department of Electrical Engineering and Automation,
>> and COMP Centre of Excellence in Computational Nanoscience
>> Aalto University, Finland
>> Personal email: mcaroba at gmail.com
>> Work: miguel.caro at aalto.fi
>> Website: http://mcaroba.dyndns.org
>>
>> _______________________________________________
>> gpaw-users mailing list
>> gpaw-users at listserv.fysik.dtu.dk
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-- 
*Dr. Miguel Caro*
/Postdoctoral researcher/
Department of Electrical Engineering and Automation,
and COMP Centre of Excellence in Computational Nanoscience
Aalto University, Finland
Personal email: *mcaroba at gmail.com*
Work: *miguel.caro at aalto.fi*
Website: http://mcaroba.dyndns.org
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