[xcrysden] PWscf structure in xcrysden problem

[Tone Kokalj]

On Thu, 2006-12-07 at 19:15 -0800, W. YU wrote:
> Dear XcrysDen uses, 
> 
> I have been testing again an again for it to show my PWscf input files. I met several problems
> and I really appreciate if someone could help me out.
> 
> 1. I tried a very simple NaCl structure input . But when I changed the parameter
>    Celldm(1) value, some times, it jush shows parts of the atoms and sometimes 
>    it works  well.

It is the first time I encountered something like this. You are right,
it happens as you reported: by merely changing the lattice parameter,
some atoms are croped that shouldn't be. This boils down to the roundoff
probelm/error. I have (hopefully) fixed it in the code.

>  2. I found if the input atomic positions are not in the same PRIMITIVE 
>     unit cell, it cannot be shown well. Is this true? 

It shouldn't be. This, again, is related to item-1 (roundoff error).
 

>     And the following is a complet input of another BCO structure input 
>     for Li2CuO2 which doesn't look the way it should be:

As far as I can see the structure looks as BCO. You will have to help me
with this, because I am not familiar with the BCO structures. Please
generate a large enough cluster of atoms of this structure and send me
such coordinates (Cartesian), so that I will be able to check what is
wrong in the xcrysden's structure.

Regards, Tone