[Pw_forum] about vc-relax of graphite
Paolo Giannozzi
giannozz at nest.sns.it
Tue Mar 6 11:32:26 CET 2007
On Mar 6, 2007, at 3:22 , li niu wrote:
> Reducing dt from 100 to 20, I found "Entering Dynamics; it = "
> increasing .
> However in all the case when P equaled about -59 (kbar) the code
> stoped and appeared
> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
> from checkallsym : error # 3
> not orthogonal operation
> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
> stopping ...
>
> What do you think about it ?
I think that you should read what is written in the users'guide:
---
\paragraph{\texttt{pw.x} stops during variable-cell optimization
in \texttt{checkallsym} with ``not orthogonal operation'' error.}
Variable-cell optimization may occasionally break the starting
symmetry of the cell. When this happens, the run is stopped
because the number of k-points calculated for the starting
configuration may no longer be suitable. Possible solutions:
\begin{itemize}
\item start with a nonsymmetric cell
\item use a symmetry-conserving algorithm: the Wentzcovitch
algorithm \\
(\texttt{cell\_dynamics='damp-w'}) shouldn't break the symmetry.
\end{itemize}
---
---
Paolo Giannozzi, Democritos and University of Udine, Italy
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