miller_index_from_sites gives wrong miller index

[utf]

The pymatgen.core.surface.miller_index_from_sites method gives incorrect results. It also seems quite temperamental about the choice of coordinates. E.g.

from pymatgen.core.structure import Structure
from pymatgen.core.surface import miller_index_from_sites

structure = Structure(
    [10, 0, 0, 0, 10, 0, 0, 0, 10],
    ['Fe', 'Fe', 'Fe'],
    [[0.5, 0.8, 0.8], [0.5, 0.4, 0.2], [0.5, 0.3, 0.7]]
)

miller_index_from_sites(structure.lattice.matrix, structure.cart_coords)

Gives [-1.04, 0. , 0. ] rather than [1, 0. , 0. ].

Also, changing the atom coordinates slightly to:

[[0.5, 0.8, 0.8], [0.5, 0.6, 0.6], [0.5, 0.3, 0.3]]

Gives [nan, nan, nan].

[shyuep]

@richardtran415 Pls investigate.

[CifLord]

Looking into it

[utf]

I've got a fix for this. Just doing some testing but will submit a PR tomorrow.

[utf]

Fixed in #1302