| 10:32:51 AM PST - Wed, Nov 21st 2012 |
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Alfred,
It is difficult to give a general rule of thumb on what the resource need is. It strongly depends on the theory you are running, the size of the system, the basis sets used, etc.
Molecular dynamics: Memory demands are not large, less then a gigabyte per processor. Can be run on a few processors, can run on small numbers of processors and scales to a couple of hundred processors.
QM/MM on medium sized clusters: Here everything will be driven by the QM part and the size of the system as I don't know what the QM part for the medium sized clusters means. If your QM is DFT, memory demands are not as great as if your would do coupled cluster theory. For DFT you probably at a minimum want to use 2 gbyte per core, whereas for coupled cluster closer to 4 gbyte would be good. Now, if you use more and more processors the memory footprint per processor will reduce. As to number of processors needed, hard to say, all depends on if you want to wait a long time for the calculation to complete (smaller set of processors) or want a fast answer to solution (large number of processors).
Plane wave: 2 gbyte would be good, can scale to large numbers of processors. Can't give you a minimum number of processors needed as it depends highly on the system.
My recommendations is to collect some typical cases that you or your users want to run and to some empirical testing.
Bert
Quote:Clusterix Nov 21st 11:59 amHello everybody and especially developers,
I have a question concerning the memory and procesors demand to perform a molecular dynamics or QM/MM on medium sized clusters (also plane wave calulations on solids):
what is the least demand on the hardware? how many processor cores and RAM should be available and moreover, how much memory capacity theses calculation usually need ?
I should mention that our university needs these data, in order to assign the correct memory demands !
thank you in advance!
greetings
Alfred |