Re: [Phonopy-users] symmetry

[Atz T. <atz...@gm...>]

Hi,

I modified the implementation of the "nosym" option. I think it became
more intuitive like ISYM=0. So if you want to test it, I will send a
development version of phonopy to you though it may contain bugs
because of rewriting many lines.

Togo

On Thu, Aug 25, 2011 at 2:33 AM, Atz Togo <atz...@gm...> wrote:
> Hi,
>
> There is no option disable symmetry finding like ISYM=0 in phonopy as
> you write. If your defect supercell has no translational symmetry,
> --nosym option should work though no message is shown clearly. For
> example, you can run
>
> % phonopy -d --dim="1 1 1"
>
> with and without --nosym opton. Then you may find the different number
> of POSCAR-xxx files. In the current implementation, the full symmetry
> is anyway searched (and the space group is shown) for the supercell
> (not the input unit cell), then all the rotation operations are
> removed, and only pure translation operations are left.
>
> Togo
>
>
> On Wed, Aug 24, 2011 at 10:05 PM, Espen Flage-Larsen
> <esp...@fy...> wrote:
>> Hi,
>>
>> Is there a way to turn of the symmetry routines during phonopy runs?
>> There was a version with --nosym, but I could not located it in the
>> archives.
>>
>> I got some imaginary frequencies (rather flat bands all over k-space).
>> Defects could of course introduce imaginary frequencies, but these flat
>> bands seems a bit troublesome. Hence I want to disable symmetry.
>> Basically, VASP puts my structure (defects in a 64 atom supercell) into
>> C1, while Phonopy wants it in SG 113 (or SG 35 with artificial low
>> tolerance). I'm now rerunning VASP with IBRION = 7, ISYM = 0 (I believe
>> phonopy should work with IBRION=7 as well, since the output is similar,
>> but without symmetry). To make the analysis consistent, symmetry
>> unrestricted calculations in phonopy would be greatly appreciated.
>>
>> Cheers
>> Espen
>>
>>
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>
>
>
> --
> Atsushi Togo
> http://atztogo.users.sourceforge.net/
> atz...@gm...
>



-- 
Atsushi Togo
http://atztogo.users.sourceforge.net/
atz...@gm...