[Pw_forum] Variable-cell optimization with constraints

[Yonas Abraham]

> 
> from the users'guide:
> --
> Variable-cell optimization may occasionally break
> the starting
> symmetry of the cell. When this happen, the run is
> stopped
> because the number of k-points calculated for the
> starting
> configuration may no longer be suitable. Possible
> solutions:
> - start with a nonsymmetric cell
> - use a symmetry-conserving algorithm: the
> Wentzcovitch
> algorithm ("cell_dynamics='damp-w'") shouldn't break
> the symmetry.
> --

Hi   Paolo,

Your replay is very helpful, But I am not sure if your
quote actually exist on the user guide. I have
searched at
http://www.pwscf.org/guide/3.0/html-single/manual.html
and on the tex files included with the release and
can't find it either. Just curious that there are not
more than one user-guides.

thanks
/yonas