[Pw_forum] Predicting the cpu time usage for bigger system withour doing the simulation

[Michael Sullivan]

Dimpy:

DFT usually scales as N^3 so I'd guess that it will take 5**3=125 times longer than the small system. You would probably gain somewhere due to fewer k-Points, etc. but that's my rough estimate.

Others may have other comments that I welcome...

Mike
michael at ihpc.a-star.edu.sg<mailto:michael at ihpc.a-star.edu.sg>
http://www.sullivan.sg/


From: pw_forum-bounces at pwscf.org [mailto:pw_forum-bounces at pwscf.org] On Behalf Of Dimpy Sharma
Sent: Tuesday, July 20, 2010 9:41 PM
To: pw_forum at pwscf.org
Subject: [Pw_forum] Predicting the cpu time usage for bigger system withour doing the simulation

Hi Quantum espresso users.
I would like to predict an approximate CPU time usage to finish one scf calculation in quantum espresso for a system with 5 supercells. I have the CPU time usage for the same sytem with one supercell.So are there  any possible ways to predict the time needed for more number of supercell (for the same system) required in quantum espresso,without doing the simulations.Can I calcuate it from the following method
Tscf= NiterTiter + Tinit

Thanks and Regards.

Dimpy

Dimpy Sharma

ETG-Group

Tyndall National Institute

Cork

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