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["D. R. Hamann" <drh@bell-labs.com>]

Dear Chun,

The stop is there for a reason.  The code will produce incorrect results
if the k set does not have the full symmetry.  You can suppress the use
and checking of symmetry by setting nsym=1, but the results will still be
wrong if your k point set breaks symmetry that the lattice actually has.

D. R. Hamann

Chun Li wrote:

Dear Hamann,

Thank you for your reply. But do you know if there exists some variable
that can suppress this kind of stop? 

Have a good weekend.

Chun Li

-----Original Message-----
From: D. R. Hamann [mailto:drh@bell-labs.com] 
Sent: Friday, October 29, 2004 5:19 PM
To: forum@abinit.org
Subject: Re: [abinit-forum] symkchk error

Dear Chun,

Yes, you can also break the symmetry of the k set with your choice
of ngkpt.  It didn't seem necessary to have the code point this out as
part of the error
message.

D. R. Hamann

Chun Li wrote:

Dear all,

I am performing rf calculations on wurtzite structure. When I try to
change the density of k-points in only one direction by modify ngkpt
(for example, from 6 2 2 to 8 2 2), the following ERROR appears in the
log file shortly after the third dataset (phonon, electric field and
strain perturbations) starts.

...
symkchk : found identity, with number  1
 symkchk : ERROR -
   k-point set must have full space-group symmetry
   there is no match for kpt   2 transformed by symmetry   2
   Action : change kptopt to 2 or 3 and/or change or use shiftk
            shiftk = 0 0 0 is always a safe choice.
-P-0000
-P-0000  leave_new : decision taken to exit ...

I have set kptopt3=2 and shiftk= 0 0 0.5 in the original input files.
However, when I try to use kptopt3=3 or set shiftk=0 0 0, the same error
still exists. Does that mean that only certain ngkpt can be used in the
calculations? I am confused about that. Hope someone can give me
suggestions. Thanks in advance.

Best regards.

Chun Li


  


  

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D. R. Hamann				Phone: 908-582-4454
Director, Theoretical Materials    	Fax:   908-582-4702
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Bell Laboratories 
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