[Spglib-users] Introduction and CASTEP

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

Hello,

I would like to introduce myself as one of the developers of the CASTEP 
DFT materials modelling code.   We plan to replace some old space group 
symmetry analysis code with spglib.

My initial tests are proving very positive about the capabilities of 
spglib for this purpose.

1) There is one piece of missing functionality we need.  This would be
    a routine similar to spg_get_dataset() but which takes as input a
    list of symmetry operations, not the lattice and co-ordinates. This
    would be to analyse a pre-supplied set of operations (rotation
    matrices and translations).  How hard would it be to add this?

2) May I ask how spglib handles non-primitive supercells. If,
    for example you were to pass a lxmxn block of primitive cells would
    spglib return the complete product group of the translation and
    rotation groups?  This is important because if only the rotation
    subset were specified the set of operations do not form a complete
    group. (As atoms can be mapped between different primitive cells).

3) Is there any built-in test whether the symmetry operations form a
    group?

sincerely

Keith Refson