[Spglib-users] Determine spacegroup given symmetry operations

[Keith R. <kr...@gm...>]

Hi,

I'd like to pick up on a question I raised a couple of years ago, as an
enhancement
to the spglib API.

The functionality I need is to pass a lattice and set of symmetry operations
as input parameters and obtain the space group - for example as an
SpglibDataset. 
Specifically the atomic co-ordinates are NOT to be used to determine the
symmetries.

The reason for this is for use in electronic structure codes in the
presence of symmetry-breaking.
It is commonly necessary to work in a subgroup, where the symmetry is
broken by, for example,
a magnetic structure, an anisotropic external stress or an electric
field or atomic displacement
perturbation, or a supercell where the supercell lattice vectors do not
transform invariantly under
the full point group.  The idea is that the caller works out the
remaining symmetries belonging to the
subgroup and passes these as input.

Following your hint and looking at the code, this does not look 
difficult in principle.  But there are
API design issues which I don't feel qualified to make.  And for
maintenance reasons it would be
best if any change was incorporated into future spglib releases.

Is it realistic to request an enhancement to spglib to do this?

sincerely

Keith Refson


On 27/03/14 04:44, Atsushi Togo wrote:
> Hello,
>
> I'm a developer of spglib.
>
> 1) I think it's not a very hard work. lattice parameters are necessary
> to be supplied for hal_get_hall_symbol, but for this purpose, just
> dummy lattice parameters should be OK.