[Pw_forum] timing vs QE version vs pools

[Paolo Giannozzi]

On Mar 6, 2009, at 18:15 , Giovanni Cantele wrote:

> - it seems that QE 3.2.3 always performs a little bit better than  
> 4.0.4,
> any hint on what (if any) is wrong in what I'm doing?

assuming that the two versions are compiled with the same options
and libraries: please check where the difference come from, in the
cpu time report at the end of each calculation
>
> - it seems that -ndiag 1 (serial algorithm for the iterative  
> solution of
> the eigenvalue problem) always performs a little bit better than the
> default (code) choice. I attribute this to the fact that only for VERY
> LARGE number of electrons this may give a difference, is that right?

VERY LARGE maybe not, but you will gain (or lose) very little unless
you have let's say several hundreds electronic states

P.
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Paolo Giannozzi, Democritos and University of Udine, Italy