[Pw_forum] PWscf can not find out symmetry operations!!!
Stefano Baroni
baroni at sissa.it
Thu Aug 31 04:01:40 CEST 2006
On Aug 31, 2006, at 3:28 AM, Ó¢Àû Å£ wrote:
> Dear Pro. Baroni
> Thanks a lot for your help!
> I have said that It was no use to set accep=1.0D-2
> and recompiled pw.x. The program still could not find
> any symmetry operation.
> Then I selected 7 inequivalent atoms, then used 8
> symmetry operations:
> x,y,z
> -x,-y,z
> -x+1/2,y+1/2,-z
> x+1/2,-y+1/2,-z
> -x+1/2,-y+1/2,-z
> x+1/2,y+1/2,-z
> x,-y,z
> -x,y,z
> to transform the 7 inequivalent atoms to 20 atoms in
> the primary unit cell.
I can hardly understand what you did. If by applying some symmetry
operations to a bunch of positions ("atoms") you obtain a larger
number of atoms, doesn't this mean that those operations are not
"symmetrry operations"???
> Then I ran scf. I use Norm-Conserving PP and chose
> ecutwfc=70,ecutrho=600.
there is ABSOLUTELY no point in using ecutrho>ecutwfc with norm
conserving PP's
> There appeared message "warning:symmetry operation #
> 3/4/5/6 not allowed fractional translation:" in the
> out file as discussed before. Only 4 symmetry
> operations without inversion could be found!
> I set ecutrho = 500 and calculated it again. Then
> all 8 symmetry operations was found!
> The stress tensor did not change too much!
> stress tensor(kbar) from original atom positions:
> 49.20 0.01 0.07
> 0.01 -16.72 0.16
> 0.07 0.16 2.61
> stress tensor(kbar) from changed atom positions:
> 49.98 0.00 0.00
> 0.00 -16.13 0.00
> 0.00 0.00 7.30
> All the nondiagonal elements changed to 0.00.
> I think changed accpe from 1.0D-5 to 1.0D-2 will be
> harmful for the calculations. So I reset it to 1.0D-5
> and recompiled.
> I have no other method to make the program find out
> all 8 symmetry operations than this method.
Have you browsed in the mailing list's archive, as I suggested?
Please, let me NOT rediscuss this point that I and others discussed
the last time a few days ago
>
> Another question:
> I use Yahoo mail box. How can I post the reply
> message next to the message which is replied in the
> mailing list. I alway started a new discussion line
> with reply message! Sorry for that!
Please, ask Terry Semel. He certainly knows better than me.
SB
---
Stefano Baroni - SISSA & DEMOCRITOS National Simulation Center -
Trieste
[+39] 040 3787 406 (tel) -528 (fax) / stefanobaroni (skype)
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