[Pw_forum] Symmetry Operations

[Katalin Gaal-Nagy]

Dear Stefano Baroni,

Thanks for your answer. If I set the FFT grid by hand, all symmetry operations 
are used. 

Regards,
Katalin Gaal-Nagy



> The ony reason I can guess is that the symmetry group of your system 
> contains fractional translations which are commensurate with the FFT 
> grid generated with one cutoff, but not with the one generated with the 
> other. Just as a test, try to perform the two calculations by explicitly 
> declaring the same fft grid (i.e. not letting the program generate the 
> minimum grid compatible with the cutoff). If this is indeed the case, 
> you may want to work out a fix?
> 
> Best wishes,
> Stefano B.
> 
> Katalin Gaal-Nagy wrote:
> > Dear PWSCF users,
> > 
> > During some convergence tests following happened:
> > 
> > I used the same input-file and changed just the kinetic energy cutoff. In 
some 
> > cases the progam used all possible symmetry operations and in some cases it 
used 
> > less. What could be a reason for this?
> > 
> > Regards,
> > Katalin Gaal-Nagy
> >