[Pw_forum] Symmetry Operations

[Katalin Gaal-Nagy]

Hello Giovanni,

thanks again. I already found a good FFT mesh. 

Enjoy your time,
Katalin


> By changing the kinetic energy cutoff, you also modify the fft grid.
> It can happen that the new grid is no longer compatible with the full
> symmetry of your crystal. If you want you can fix the fft grid in the
> input file (from pwdocs/INPUT_PW):
> 
> nr1,nr2,nr3  integer
>              three-dimensional FFT mesh (hard grid) for charge
>              density (and scf potential). If not specified
>              the grid is calculated based on the cutoff for
>              charge density (see also "dual")
> 
> for a reliable calculation please set nr1,nr2,nr3 values larger (or
> equal) to those calculated by pw.x. 
> 
> 	giovanni
>