[Pw_forum] LSDA calculation with Hybrid functional

[Lorenzo Paulatto]

Hi Rita,
my guess is that the calculation is just much slower than you expect! Exact 
exchange is slow in general.

Try to do a test run with:
- only one k-point
- a much lower cutoff

This will give you an idea of the time it will take to reach convergence, than 
you can start to crank it up.

Note that the time should increase with cutoff to power 3/2 and with the square 
of the number of k-points ! 

You may also want to set nqx1, nqx2, nqx3 to a divisor of the number of k-
points in the three directions (no luck with 7, I'm afraid!) which reduces the 
exchange integral to a subset of the k-points, at the expenses of some 
accuracy

cheers



On Friday, October 28, 2016 7:54:59 PM CEST Rita Maji wrote:
> Hi Lorenzo,
> I am doing LSDA calculation for a 5x5 doped graphene calculation, to see
> the change in magnetic property for hybrid functional I am trying to do
> with PBE0, it is taking long time and also not printing total energy at
> each scf steps so that I can see whether it is converging properly or not,
> and also not showing any error during running. First time I am using Hybrid
> functional so I have used all default parameters as of now, Here I have
> attached the input file, any suggestion will be very much helpful.
> 
> Thanks,
> Rita
> 
> On Fri, Oct 28, 2016 at 2:31 PM, Lorenzo Paulatto <
> 
> lorenzo.paulatto at impmc.upmc.fr> wrote:
> > Dear Rita,
> > please provide more details.
> > 
> > kind regards
> > 
> > On Friday, October 28, 2016 11:01:09 AM CEST Rita Maji wrote:
> > > Dear all,
> > > during LSDA calcultion with hybrid functional (PBE0) it is not writing
> > > total and absolute magnetization and also all the contribution to total
> > > energy, can anybody help me .
> > > 
> > > 
> > > Thanking You,
> > > Rita Maji
> > > NISER, Bhubaneswar
> > 
> > --
> > Dr. Lorenzo Paulatto
> > IdR @ IMPMC -- CNRS & Université Paris 6
> > phone: +33 (0)1 44275 084 / skype: paulatz
> > www:   http://www-int.impmc.upmc.fr/~paulatto/
> > mail:  23-24/4é16 Boîte courrier 115, 4 place Jussieu 75252 Paris Cédex 05
> > 
> > _______________________________________________
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-- 
Dr. Lorenzo Paulatto 
IdR @ IMPMC -- CNRS & Université Paris 6
phone: +33 (0)1 44275 084 / skype: paulatz
www:   http://www-int.impmc.upmc.fr/~paulatto/
mail:  23-24/4é16 Boîte courrier 115, 4 place Jussieu 75252 Paris Cédex 05