[Pw_forum] on nosym=.true.

[Gabriele Sclauzero]

On 11/24/2010 11:29 AM, Mahmoud Payami wrote:
> Dear Gabriele,
> Thank you very much for your reply.
> >Do you mean "Warning: symmetry operation #N not >allowed"? This is 
> not an error, but simply a warning,
> Yes, it is.
>
> >I doubt that this would cause the program to stop.
> But it stops a process in the mpi running.

At which point? Does it display some error message? You are not giving 
enough information to understand the problem.

>
> > All.
> How can I constrain the system just ignore symmetry operations wrt the 
> xoy plane (because the z coordinates change)?

I thought you had a slab geometry... if so, there should not be any 
symmetry operations involving a change in z coordinate (apart maybe a 
mirror plane and the inversion, depending on how you have built the 
slab). Then there are only operation involving x and y coordinates left. 
If you want to ignore those, then you should be left with no symmetries...

What you can do is to very slightly displace some atoms in the xy plane 
such that some symmetry operations are not verified anymore. Anyway, if 
you want to remove a subset of symmetry operations in a systematic way I 
think you should modify the code.


GS

> Bests,
> m.
>
>
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-- 

Gabriele Sclauzero, EPFL SB ITP CSEA
PH H2 462, Station 3, CH-1015 Lausanne

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