[Pw_forum] new bfgs: strange behavior doing vc-relax

[Максим Попов]

Dear Dr. Giannozzi,

thank you for the answer! I could find it myself looking in the output file
a bit more carefully...
One thing, which is somehow contrary to my expectations, is that the final
scf energy is higher
than the last one from vc-relax. Could you, please, elaborate a bit on the
matter?

Best  regards,
Maxim.

2011/4/19 Paolo Giannozzi <giannozz at democritos.it>

>
> On Apr 18, 2011, at 15:58 , Максим Попов wrote:
>
> > comparing vc-relax calculations between BFGS(4.2.1)
> > and the latest BFGS(from CVS) I faced  with a following problem
>
> there is no problem, or at least, not in your output. There are
> two differences wrt the previous version:
> 1)  the first optimization step in vc-relax algorithm was modified,
> so vc-relax should now converge slightly better
> 2) since everybody was complaining all the time that "I made a
> scf calculation and got different result from vc-relax", a final
> scf step with G-vectors appropriate for the final cell was added.
> Why one gets different results etc etc has been explained no
> less than 1001 times in this mailing list.
>
> There can be a problem in this last step, explained here:
> http://www.democritos.it/pipermail/pw_forum/2011-April/020052.html
> Solution, for the time being: ignore it.
>
> P.
> --
> Paolo Giannozzi, Dept of Chemistry&Physics&Environment,
> Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
> Phone +39-0432-558216, fax +39-0432-558222
>
>
>
>
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