[Wien] Computer resources for a 64-processor cluster

[Torsten Andersen]

Dear Mr. Iglesias,

this can only be answered by a test run... the required memory, and 
especially the disk space depends very much on the number of atoms, the 
type of atoms, the cutoff values in case.in1c and case.in2c, and the 
number of k-points.

For the memory, my experience says that 2GB per processor is sufficient 
under k-point parallelization.

Disk space... depends on your calculation, but a few hundred GB should 
be sufficient for most cases.

CPU time I can not say anything about... you would need to run a test 
run. Make a test for 1 k-point on one CPU and scale it linearly (plus 
epsilon). For k-point parallelization you need at least as many k-points 
as processors.

For MPI-jobs, the linear scaling doesn't work, since also your network 
speed has to be taken into account... don't use it if you can avoid it.


Best regards,
Torsten Andersen.

ROBERTO LUIS IGLESIAS PASTRANA wrote:
> Hi all!
> 
> I could not find in the FAQs or in the mailing list whether this question has been answered before or not, so please excuse me if I am asking something that has been asked before
> We've got a 64-processor cluster at my institution and the administrator wants to know which will be the RAM and disk space usage and the CPU time needed for the parallelization jobs we intend to perform. Basically, we aim at studying energetics involving both strucural and volume relaxation in magnetic binary alloy systems, through a supercell approach. I know that NMATMAX should be larger than 10000, in order to use fine grain parallelization, but I have never performed it myself, so I don't really have an estimation on the above parameters.
> If anybody is willing to help, I would be much grateful.
> 
> Roberto Iglesias
> 
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-- 
Dr. Torsten Andersen        TA-web: http://deep.at/myspace/
AG Hübner, Department of Physics, Kaiserslautern University
http://cmt.physik.uni-kl.de    http://www.physik.uni-kl.de/