[Wien] memory configuration for k-point parallelization

[Tomohiko Tasaka]

Hello,

Thanks for your kind reply. if possible, could you advise me of the minimum
system to analyze core-orbital spectroscopy (e.g. x-ray absorption spectrum)
for a case with 100 atoms/cell?
for example, how about 2 machines which has dual cores with 4 GB RAM (total
4 cores, 8 GB RAM)? is it sufficient on condition of mix parallelization?

Further, I'd like to confirm whether these parallel jobs require a single
master (control) node to install much more requirement resources(e.g. RAM
or any I/O bandwidth) than client nodes.


Sorry, vague question.
Tomo

-----Original Message-----
From: wien-bounces at zeus.theochem.tuwien.ac.at
[mailto:wien-bounces at zeus.theochem.tuwien.ac.at] On Behalf Of Peter Blaha
Sent: Monday, September 01, 2008 10:24 PM
To: A Mailing list for WIEN2k users
Subject: Re: [Wien] memory configuration for k-point parallelization

For a case with 100 atoms/cell most likely you will have only 1 k-point,
thus k-point parallel is not possible, only mpi-parallel.

In case you have a metallic (magnetic) case, you may still have a few
k-points and than k-parallel is still most efficient, provided the
memory (RAM) is large enough ON EACH NODE (has nothing to do with the
master node).

If you have enough nodes available, one can also mix k-point and
mpi-parallel
mode, eg. when you have 4-kpoints, but you have 16 nodes, run 4-mpi-jobs
per k-point.

mpi-version only with the most recent versions.

Tomohiko Tasaka schrieb:
> Dear wien2k users,
> 
>  
> 
> I heard that the k-point parallel calculation with wien2k old version
> 
> needs huge physical memory for a master node. The reason is that
> 
> the master node (job submitting node) collects many distributed results
> 
> which are calculated by each calculation node, at the same time.
> 
> Therefore, there is difficulty in executing k-point parallel calculation
> 
> for the large system (e.g. 100 atoms per unit cell).
> 
>  
> 
> is this correct regardless of the version? please advise.
> 
>  
> 
> Any information would be appreciated.
> 
>  
> 
> With best regards,
> 
> Tomo
> 
>  
> 
> 
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> 
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-- 

                                       P.Blaha
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Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
Phone: +43-1-58801-15671             FAX: +43-1-58801-15698
Email: blaha at theochem.tuwien.ac.at    WWW:
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