[Pw_forum] timing vs QE version vs pools

Paolo Giannozzi giannozz at democritos.it
Fri Mar 6 21:45:51 CET 2009

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

Paolo Giannozzi, Democritos and University of Udine, Italy

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