[Pw_forum] (no subject)

[degironc]

stress converges slowly with cutoff  and if you are not at full convergence
setting the variables qcutz=150., q2sigma=2.0, ecfixed=24.0, modifies 
the kinetic energy
of the electrons beyond 24 ry adding a large penalty function and the 
"effective" cutoff of your
calculation is something around 24 ry.
This affects the total energy and the stress.
Also having smearing instead of fixed occupation makes a difference but 
if your system is gapped it should not be large.
In order to compare output of the two codes you should use the same 
setting in both.

stefano


CP>

> &SYSTEM
>                       ibrav = 14,
>                   celldm(1) = 24.4946,
>                   celldm(2) = 1.0,celldm(3) = 1.0,celldm(4) = 0.0,celldm(5) = 0.0,celldm(6) = 0.0,
>                         nat = 64,
>                        ntyp = 2,
>                     nbnd=288,nelec=576,nspin=1,
>                     ecutwfc = 30.0 ,
>                     ecutrho = 240 ,
>                 occupations = 'fixed' ,
>		xc_type = 'PBE',
>
>   qcutz=150., q2sigma=2.0, ecfixed=24.0,
> /
>
PW>

> &SYSTEM
>                       ibrav = 1,
>                   celldm(1) = 24.4946,
>                         nat = 64,
>                        ntyp = 2,
>                     ecutwfc = 30.0 ,
>                     ecutrho = 240 ,
>                 occupations = 'smearing' ,
>                     degauss = 0.02 ,
>                    smearing = 'fermi-dirac' ,
> /
> &ELECTRONS
>  
>