[Pw_forum] PW.x homogeneous electric field berry phase calculation in trigonal cell

[Lorenzo Paulatto]

On Monday, February 13, 2017 11:43:08 AM CET Louis Fry-Bouriaux wrote:
> Finally when you were talking about the bottleneck, I suppose you were
> talking about the efield code, my impression so far is this is not a
> problem using 4 processors, I will also test using 8 and compare the time
> taken. I have no idea how fast it 'should' be with proper parallisation,
> assuming it is possible to parallelise.

When you increase the number of CPUs, you would expect the time to decreased 
linearly, if over a certain number of CPUs it stops decreasing or if it 
decreases slower than linear, it is a bottleneck. This will always happen 
eventually, but with berry/lefield it happens much sooner.

Thank you for reporting back! I hope this information will be useful to future 
users

-- 
Dr. Lorenzo Paulatto 
IdR @ IMPMC -- CNRS & Université Paris 6
phone: +33 (0)1 442 79822 / skype: paulatz
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