Re: [Phonopy-users] Need help to used modulation command

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

Hi,

> Do you need the input files?

Maybe. Please think about how you could motivate me to solve your problem.

Togo

On Fri, Feb 13, 2026 at 4:18 PM Naveena P.Sivam <nav...@gm...>
wrote:

> Hi
>
> I followed the instructions in the document, but I am unable to modulate
> the atom. It shows errors. Do you need the input files?
>
> -naveena
>
> On Fri 13 Feb 2026 at 08:16, Atsushi Togo <atz...@gm...> wrote:
>
>> Hi,
>>
>> > How to perform this?
>>
>> It is written in the documentation.
>>
>> > if you need any additional input, let me know.
>>
>> I need to reproduce your issue.
>>
>> Togo
>>
>> On Fri, Feb 13, 2026 at 1:59 PM Naveena P.Sivam <nav...@gm...>
>> wrote:
>>
>>> Hi,
>>>
>>> I need help to perform atomic modulation with a specific q-point
>>> (pre-processing after DFPT calculation using QE)  using phonopy. MODULATION
>>> = (command). How to perform this?
>>>
>>> if you need any additional input, let me know.
>>>
>>> with regards
>>> Naveena
>>>
>>> On Fri, Feb 13, 2026 at 4:38 AM Atsushi Togo <atz...@gm...> wrote:
>>>
>>>> Hi,
>>>>
>>>> Information is too little to see the issue. So it is difficult to
>>>> answer.
>>>>
>>>> > I found your youtube videos
>>>>
>>>> I think those are not my youtube videos.
>>>>
>>>> Togo
>>>>
>>>>
>>>> On Fri, Feb 13, 2026 at 1:22 AM Naveena P.Sivam <nav...@gm...>
>>>> wrote:
>>>>
>>>>> Hello
>>>>> I am trying to do atomic modulation (atomic displacement) with respect
>>>>> to the normal mode at the specific q point. I tried to use this command
>>>>> line:
>>>>> phonopy --qe --modulation 2 2 1, 0.000000000   0.433012702
>>>>> 0.000000000 1 0.03 0 -c TiS2_primitive_scf.in --dim 2 2 1 -v.
>>>>>
>>>>> But it provides error like this:
>>>>>
>>>>> phonopy --qe --modulation 2 2 1, 0.000000000   0.433012702
>>>>> 0.000000000 1 0.03 0 -c TiS2_primitive_scf.in --dim 2 2 1 -v
>>>>>         _
>>>>>   _ __ | |__   ___  _ __   ___   _ __  _   _
>>>>>  | '_ \| '_ \ / _ \| '_ \ / _ \ | '_ \| | | |
>>>>>  | |_) | | | | (_) | | | | (_) || |_) | |_| |
>>>>>  | .__/|_| |_|\___/|_| |_|\___(_) .__/ \__, |
>>>>>  |_|                            |_|    |___/
>>>>>                                       2.47.1
>>>>>
>>>>> -------------------------[time 2026-02-06
>>>>> 16:53:41]-------------------------
>>>>> Compiled with OpenMP support (max 8 threads).
>>>>> Python version 3.11.11
>>>>> Spglib version 2.7.0
>>>>>
>>>>> Calculator interface: qe
>>>>> Crystal structure was read from "TiS2_primitive_scf.in".
>>>>> Unit of length: au
>>>>> Modulation mode
>>>>> Settings:
>>>>>   Supercell: [2 2 1]
>>>>> Spacegroup: P-3m1 (164)
>>>>> Number of symmetry operations in supercell: 48
>>>>> ------------------------------ primitive cell
>>>>> ------------------------------
>>>>> Lattice vectors:
>>>>>   a    6.460973493253429    0.000000000000000    0.000000000000000
>>>>>   b   -3.230486746626715    5.595367178253872    0.000000000000000
>>>>>   c    0.000000000000000    0.000000000000000   34.015070466894429
>>>>> Atomic positions (fractional):
>>>>>    *1 Ti  0.00000000000000  0.00000000000000  0.50000000000000  47.867
>>>>>    *2 S   0.66666700000000  0.33333300000000  0.57891028530000  32.065
>>>>>     3 S   0.33333300000000  0.66666700000000  0.42108971470000  32.065
>>>>> -------------------------------- unit cell
>>>>> ---------------------------------
>>>>> Lattice vectors:
>>>>>   a    6.460973493253429    0.000000000000000    0.000000000000000
>>>>>   b   -3.230486746626715    5.595367178253872    0.000000000000000
>>>>>   c    0.000000000000000    0.000000000000000   34.015070466894429
>>>>> Atomic positions (fractional):
>>>>>    *1 Ti  0.00000000000000  0.00000000000000  0.50000000000000  47.867
>>>>> > 1
>>>>>    *2 S   0.66666700000000  0.33333300000000  0.57891028530000  32.065
>>>>> > 2
>>>>>     3 S   0.33333300000000  0.66666700000000  0.42108971470000  32.065
>>>>> > 3
>>>>> -------------------------------- super cell
>>>>> --------------------------------
>>>>> Lattice vectors:
>>>>>   a   12.921946986506859    0.000000000000000    0.000000000000000
>>>>>   b   -6.460973493253429   11.190734356507743    0.000000000000000
>>>>>   c    0.000000000000000    0.000000000000000   34.015070466894429
>>>>> Atomic positions (fractional):
>>>>>    *1 Ti  0.00000000000000  0.00000000000000  0.50000000000000  47.867
>>>>> > 1
>>>>>     2 Ti  0.50000000000000  0.00000000000000  0.50000000000000  47.867
>>>>> > 1
>>>>>     3 Ti  0.00000000000000  0.50000000000000  0.50000000000000  47.867
>>>>> > 1
>>>>>     4 Ti  0.50000000000000  0.50000000000000  0.50000000000000  47.867
>>>>> > 1
>>>>>    *5 S   0.33333350000000  0.16666650000000  0.57891028530000  32.065
>>>>> > 2
>>>>>     6 S   0.83333350000000  0.16666650000000  0.57891028530000  32.065
>>>>> > 2
>>>>>     7 S   0.33333350000000  0.66666650000000  0.57891028530000  32.065
>>>>> > 2
>>>>>     8 S   0.83333350000000  0.66666650000000  0.57891028530000  32.065
>>>>> > 2
>>>>>     9 S   0.16666650000000  0.33333350000000  0.42108971470000  32.065
>>>>> > 3
>>>>>    10 S   0.66666650000000  0.33333350000000  0.42108971470000  32.065
>>>>> > 3
>>>>>    11 S   0.16666650000000  0.83333350000000  0.42108971470000  32.065
>>>>> > 3
>>>>>    12 S   0.66666650000000  0.83333350000000  0.42108971470000  32.065
>>>>> > 3
>>>>>
>>>>> ----------------------------------------------------------------------------
>>>>>   ___ _ __ _ __ ___  _ __
>>>>>  / _ \ '__| '__/ _ \| '__|
>>>>> |  __/ |  | | | (_) | |
>>>>>  \___|_|  |_|  \___/|_|.
>>>>>
>>>>> Also, it creates modulation.conf which contains:
>>>>> DIM = 2 2 1
>>>>> MODULATION = 2 2 1, 0 0.433012702 0 1 0.03 0.
>>>>>
>>>>> Also, I found this idea from:
>>>>> https://phonopy.github.io/phonopy/setting-tags.html.
>>>>>
>>>>> Just today I started to use this package and I found your youtube
>>>>> videos discussing how to use phonopy with qe. So I thought I could ask for
>>>>> some help. kindly help me if you have any ideas.
>>>>>
>>>>> with regards
>>>>> Naveena P.
>>>>> _______________________________________________
>>>>> Phonopy-users mailing list
>>>>> Pho...@li...
>>>>> https://lists.sourceforge.net/lists/listinfo/phonopy-users
>>>>>
>>>>
>>>>
>>>> --
>>>> Atsushi Togo
>>>> _______________________________________________
>>>> Phonopy-users mailing list
>>>> Pho...@li...
>>>> https://lists.sourceforge.net/lists/listinfo/phonopy-users
>>>>
>>> _______________________________________________
>>> Phonopy-users mailing list
>>> Pho...@li...
>>> https://lists.sourceforge.net/lists/listinfo/phonopy-users
>>>
>>
>>
>> --
>> Atsushi Togo
>> _______________________________________________
>> Phonopy-users mailing list
>> Pho...@li...
>> https://lists.sourceforge.net/lists/listinfo/phonopy-users
>>
> _______________________________________________
> Phonopy-users mailing list
> Pho...@li...
> https://lists.sourceforge.net/lists/listinfo/phonopy-users
>


-- 
Atsushi Togo