[Q-e-developers] Fwd: Re: [Q-e-commits] r10603 - trunk/espresso/PW/src

[Paolo Giannozzi]

Note that the latest "reshuffling" of loops does not (or at least,
should not) change anything in the way self-consistency is achieved: 
it just re-orders things into a more logical and transparent way

Paolo

On Mon, 2013-11-18 at 22:05 +0100, Lorenzo Paulatto wrote:
> On 11/18/2013 06:44 PM, giannozz wrote:
> > Author: giannozz
> > Date: 2013-11-18 18:44:11 +0100 (Mon, 18 Nov 2013)
> > New Revision: 10603
> > 
> > Modified:
> >    trunk/espresso/PW/src/electrons.f90
> > Log:
> > More exx cleanup: the self-consistency loop at fixed exchange potential is no 
> > longer intertwined with the loop over exchange. Calculation and printout of
> > the various energy terms is less confusing (in my opinion). There is still 
> > a small but non-negligible difference between gamma-only and k=0, but this
> > should not be related to these changes.
> > 
> > 
> 
> About this subject: it is smart to have two concentric SCF cycles, one
> to converge the wavefunctions and one that exppensively updates the Fock
> operator when they are converged.
> 
> However, if you set up the equally smart adaptive threshold the Fock
> operator will still be updated at almost every cycle.
> 
> So now we have two smart tricks, each of them extremely complicated, but
> I feel that they almost exactly cancel each other out.
> 
> Anybody with more experience on real-world EXX calculations cares to
> comment?
> 
> cheers
> 
> 

-- 
Paolo Giannozzi, Dept. Chemistry&Physics&Environment, 
Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
Phone +39-0432-558216, fax +39-0432-558222