[Pw_forum] magic cell size in FPMD

[Paolo Giannozzi]

On Tuesday 08 November 2005 17:54, Davide Ceresoli wrote:

> I'm running a simple calculation (1 atom in a cubic cell),
> in serial, on a PC, and vary the cell size (celldm(1)).
>
> celldm(1) = 18.897261     (10 angstrom) everything is fine!
> celldm(1) = 18.0          crashes when writing restart to disk
> celldm(1) = 18.8          crashes when writing restart to disk
> celldm(1) = 19.0          crashes when writing restart to disk
> celldm(1) = 22.676714     (20 angstrom) crashes when writing restart to
> disk
>
> It's FPMD from CVS (end of september 2005)

you are using SIC (self-interacting correction), a rather new 
and experimental feature that might have some problems. 
It is likely that you hit a bug that shows up only in some
cases.

Note that SIC works only with fpmd. In the newest CVS versions,
you have to specify calculations='fpmd' to run the fpmd features
that are not yet ported to cp

Paolo

-- 
Paolo Giannozzi             e-mail:  giannozz at nest.sns.it
Scuola Normale Superiore    Phone:   +39/050-509876, Fax:-563513 
Piazza dei Cavalieri 7      I-56126 Pisa, Italy