Re: [Spglib-users] symmetrizing positions/cell vectors without altering cell?

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

If the distortion is not that much, then the approach by
Grosse-Kunstleve and Adams should work. If you write a python script,
I think I can comment to it. The C-code is about here,
https://github.com/atztogo/spglib/blob/master/src/site_symmetry.c#L244

Togo

On Mon, Sep 25, 2017 at 10:08 PM, Noam Bernstein
<noa...@nr...> wrote:
>
> On Sep 25, 2017, at 8:54 AM, Atsushi Togo <atz...@gm...> wrote:
>
> Hi,
>
> Hi Togo - thanks for the quick response. Since I’m using the python
> interface, which I don’t think has direct access to that routine, I’m not
> sure, but I don’t think so, at least if I’m reading the documentation
> correctly.
>
>
> This for python,
> https://atztogo.github.io/spglib/python-spglib.html#standardize-cell
>
>
> thanks.
>
>
> I'm sure that the paper's scheme works for atomic positions, but the
> paper doesn't mention about symmetrization of basis vectors if I
> remember correctly.
>
>
> I don’t actually care about cell vectors right now, so if I could just get
> atomic positions symmetrized I’d be satisfied.
>
>
> Let me put together an example based on the underlying C library, to take
> the python interface out of the process, and I’ll post a followup.
>
>
> But symmetrization is uneasy since it means the original input
> structure is distorted. So we have to determine how we want to
> symmetrize it. This makes me difficult to answer this type of
> question.
>
>
> I know what symmetry group I want the final configuration to be (it’s
> determined by spglib, in fact, just based on a loose symprec).  Basically, I
> think what I want is “no_idealize=0”, so move the atoms to symmetry required
> positions, but without touching the unit cell vectors at all.  Neither
> transforming into a primitive cell (what happens when to_primitive=1), nor
> transforming into a standard cell (what happens when to_primitive=0).  Just
> the original lattice vectors.
>
> Noam
>
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> Noam Bernstein, Ph.D.
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> U.S. Naval Research Laboratory
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>



-- 
Atsushi Togo
Elements Strategy Initiative for Structural Materials, Kyoto university
E-mail: atz...@gm...