[Pw_forum] symmetry operation not allowed

[Stefano de Gironcoli]

Dear Lily Anh,
   the fractional translations that are discarded by the code have all 
coordinates very close to multiples of 0.25, 0.5 or 0.0 but  not exactly 
0.25, 0.5, 0.0.
   I think it will be very difficult to get rid of these warning 
messages by playing with nr1,nr2,nr3 only...
   You should instead see if by rigidly translating your configuration 
(so that, for instance, one of the atoms is exactly at the origin) you 
can obtain exactly 0.25 0.5 and 0.0 fractional translations. In that 
case it will be sufficient to take some nr1, nr2,nr3 that are multiple 
of 4 in order to eliminate the warnings.
 
  Hope this helps,
 
    stefano

Lily Anh wrote:
>
> Dear all,
>
> I know this is a old question and I also read the previous answer 
> about this.
>
> I test with different ecutwfc ,  ecutrho (until 30 times of ecutwfc) , 
> and K-grid. However, the problem still exists.  Since the calculation 
> expense is always in concern, so I want to use symmetry during the 
> calculation.
>
> I attach the output and input file here for reference.
>
>      Output file:
>
>      Current dimensions of program pwscf are:
>
>      ntypx =10   npk =40000  lmax = 3
>
>      nchix = 6  ndmx = 2000  nbrx =14 nqfx = 8
>
>      warning: symmetry operation #  2 not allowed.   fractional 
> translation:
>
>       -0.4999900 -0.4999400 -0.5000000  in crystal coordinates
>
>      warning: symmetry operation #  3 not allowed.   fractional 
> translation:
>
>        0.0000100 -0.5000000 -0.2498700  in crystal coordinates
>
>      warning: symmetry operation #  4 not allowed.   fractional 
> translation:
>
>       -0.5000000  0.0000600  0.2501300  in crystal coordinates
>