The ABINIT Users Mailing List ( CLOSED )

["Anglade Pierre-Matthieu" <anglade@gmail.com>]

Hi,

Apparently there is no better value for ionmov at present. I don't
know the reasons why this algorithm is supposed to be most efficient
for system with few degrees of reedom either. This last statement
seems surprising to me since Broyden method is a very good algorithm
for local minimisation. If you really need it you might try to
implement a preconditioner to your minimisation problem. This may be
the only efficient improvement you can add to BFGS. It consist in
adding an explicit hessian guess to the implicit hessian evalutaion
done by BFGS.

Regards

PMA

On 4/4/07, Chol-Jun Yu <yucj@ghi.rwth-aachen.de> wrote:
> Dear users,
>
> I found that it could take much time (sometimes BFGS steps more than 60 in
> order to arrive convergence, 5*10-5 Ha/Bohr) to relax the atomic positions if
> the number of atoms is much larger more than 50, for example, for surface
> supercell. I usually used the ionmove=2. Is it possible to reduce the BFGS
> steps by using other values of "ionmov" parameter?
>
> With best wishes,
>
> Yu Chol Jun.


--
Pierre-Matthieu Anglade