[Pw_forum] error: nc already filled

[Stefano de Gironcoli]

On Mon, 10 Feb 2003, Jorge Mario Osorio Guillén wrote:
Dear Jorge Osorio,

     the problem you report looks like you are feeding q2r.x with a q 
vector that it already knows.  
     only non equivalent points in the BZ of the crystal must be 
calculated by the phonon code, the resulting dynamical matrix files will 
contain also the matrices for the remaining equivalent q-points.
     It is possible that you have calculated more points than are needed.

for instance I see that the point
> 0.0000000000  0.0000000000  1.0739619260
which is equivalent to the gamma point is present in your grid.
when feeded to the q2r.x program, it will correctly complain for this 
duplication.

check your grid.

look for the string " q =" in all your dynamical matrix files

there should be one matching for each point in the grid plus an additinal 
matching per file since the results of the diagonalization of the first 
point of the star of q vectors is also writen in the file.  

therefore 

grep -e "q =" ti.dyn_* | wc

should return a number of lines equal to 
nr1*nr2*nr3 + #files

if not your grid is either incomplete or (should be your case) redundant.

Obviously even if the number is correct the grid could still be wrong, 
however this is a simple check to make.

regards,

  Stefano de Gironcoli 


> Dear All,
> 
> I am a new user of  the PWSCF code and  I succeed  with calculations for
> 
> cubic
> systems.  But,  doing a calculation for an orthorhombic system, with the
> 
> following
> reciprocal axes as the ouput file prints out:
> 
>      reciprocal axes: (cart. coord. in units 2 pi/a_0)
>                b(1) = (  1.0000 -1.4625  0.0000 )
>                b(2) = (  1.0000  1.4625  0.0000 )
>                b(3) = (  0.0000  0.0000  1.0740 )  .
> 
> I got some troubles.  Actually, I used more precision in the vectors of
> the
> reciprocal
> lattice in order to generate the q-point grid (1.462525295 and
> 1.073961926).  Some of
> the q-points are:
> 
> 0.0000000000  0.0000000000  0.2684904815
> 0.0000000000  0.0000000000  1.0739619260
> 0.5000000000  0.3656313238  0.2684904815
> 0.2500000000 -0.3656313238  0.2684904815
> 0.2500000000 -0.3656313238  0.5369809630
> 0.2500000000 -0.7312626475  0.5369809630
> 0.5000000000 -0.3656313238  0.2684904815
> 1.0000000000 -0.3656313238  0.2684904815
> etc., etc.,
> 
> As you can  see, they are commensurable with the reciprocal lattice.
> 
> The dynamical matrix calculation for all these q-points has been done.
> But,
> when I run
> the q2r.x  program to  get the interatomic foces constants in real space
> I
> got the
> following:
> 
>  q=   0.00000000  0.00000000  0.00000000
>   reading dyn.mat. from file ti.dyn_0.00_0.00_0.26
>   nqs=   2
>  q=   0.00000000  0.00000000  0.26849048
>    1   1   1
> 
>  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
>      from init : error #         1
>       nc already filled
>  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
> 
> or for example
> 
>  q=   0.00000000  0.00000000  0.00000000
>   reading dyn.mat. from file ti.dyn_0.05_0.36_0.26
>   nqs=   4
>  q=   0.50000000  0.36563132  0.26849048
>    1   1   1
> 
>  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
>      from init : error #         1
>       nc already filled
>  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
> 
> Has someone the same kind of error before?
> 
> How could I solve this?
> 
> Is it related with the q-point grid?
> 
> Any good sugestion that you can give me it is very welcome.
> 
> With best,
> 
> Jorge Osorio
> 
> 
> 
> --
> Jorge Mario Osorio Guillen   |Telephone: (46-018)-471 35 67
> Condensed Matter Theory Group|Fax: (46-018)-471 35 24
> Department of Physics        |e-mail: Jorge.Osorio at fysik.uu.se
> Uppsala University           |www.fysik4.fysik.uu.se
> Box 530                      |
> SE-751 21 Uppsala-Sweden     |
> 
> 
>