Re: [Spglib-users] Irreducible k points from custom k mesh

[cheng s. <sha...@gm...>]

Dear Prof. Togo,

Thanks for your reply. I was thinking about using the rotation
symmetry operator to find the irreducible k points from the k point list.

For example, I want to apply the symmetry operator to find all the
duplicates of the current k_point and check if any of them is in the
irreducible k point list.

However, I am a bit confused about how the rotation symmetry operator
should be used.

In the get_symmetry section, it says
new_vector[3x1] = rotation[3x3] * vector[3x1] + translation[3x1]

While in the definitions and conventions section, there is an equation:
(𝐚̃ ,𝐛̃ ,𝐜̃ )=(𝐚,𝐛,𝐜)𝑊

Should I use the rotation * k_point, or using k_point * rotation?
Do I need to apply some modifications like inversion and transpose to the
rotation matrix before applying it to the k points?

Sorry for bothering you again, and I am appreciated if you could help me
out here.

Best,
Cheng



On Sun, Jun 20, 2021 at 5:42 PM Atsushi Togo <atz...@gm...> wrote:

> Hi,
>
> No. It's not possible.
> But it is trivial to implement.
>
> Togo
>
> On Sun, Jun 20, 2021 at 4:13 PM cheng shao <sha...@gm...> wrote:
> >
> > Dear Prof. Togo,
> >
> > I am a new user of the spglib, and thanks for your efforts in developing
> and maintain it.
> >
> > I have a quick question: is it possible to find the irreducible k points
> from the custom-defined k mesh?
> >
> > Say I have a uniform k mesh points (in a different order as the
> auto-generated one from spglib),
> > Is it possible to identify the irreducible k points and the weight
> factor from it.
> >
> > In the example, there is a function `grid = get_ir_reciprocal_mesh(mesh,
> cell, is_shift=[0, 0, 0])`,
> > can we replace the integer number mesh to a vector of k points?
> >
> > Best,
> > Cheng
> > ----
> > Dr. Cheng Shao
> > Post-Doctoral Researcher
> > Dept. of Mechanical Engineering
> > The University of Tokyo
> >
> >
> >
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>
>
>
> --
> Atsushi Togo
>
>
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