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

[Paolo Giannozzi]

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