Re: [Phonopy-users] Phonopy encounters symmetry problem for some supercells

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

I forget about older versions after releasing newer one.

Togo

On Thu, Apr 25, 2013 at 9:39 AM,  <ti...@ca...> wrote:
> Thanks, so this is a known bug in the old version?
> Best,
> Tian
>
>> Hi,
>>
>> Please use the latest version.
>> http://sourceforge.net/projects/phonopy/
>>
>> Togo
>>
>> On Thu, Apr 25, 2013 at 2:42 AM, Tian Lan <ti...@ca...> wrote:
>>> Dear all,
>>>
>>> I am using phonopy to calculate phonons for a cuprite structure. I got
>>> some
>>> negative frequencies in acoustic modes for 2 by 2 by 2 supercell. In
>>> order
>>> to check whether it really is an unstable structure, or some numerical
>>> fake,
>>> I plan to increase the supercell in one dimension to enhance the
>>> resolution
>>> there (I guess this method should work).
>>>
>>> Therefore, I generate a 1 by 1 by 10 supercell, phonopy created it well
>>> and
>>> printed down the correct symmetry, and VASP did the force calculation
>>> well,
>>> and phonopy got the force_sets, so far so good. However, when I tried to
>>> get
>>> the dispersion or DOS (I have set DIM= 1 1 10 in the control tab),
>>> bunches
>>> of lines saying 'Phonopy encounters symmetry problem', followed by
>>> "Input
>>> forces are not enough to calculate force constants, or something wrong
>>> (e.g.
>>> crystal structure does not match)."
>>>
>>> I am confused about this error because I am using phonopy generated
>>> structure, cuprite is cubic structure, but I don't think supercell has
>>> to be
>>> the same in all dimension. I changed to a 2 by 2 by 4 cell, the same
>>> problems still exist.
>>>
>>> Could someone help me out, I am using a 1.1 version.
>>>
>>> Thanks!
>>>
>>> Best,
>>> Tian
>>>
>>> --
>>> Lan, Tian
>>> Ph.D. Candidate, Department of Applied Physics and Materials Science
>>> California Institute of Technology,
>>> Caltech M/C 138-78, Pasadena, CA, 91125
>>>
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>>
>>
>>
>> --
>> Atsushi Togo
>> http://atztogo.github.com/
>> atz...@gm...
>>
>
>



-- 
Atsushi Togo
http://atztogo.github.com/
atz...@gm...