Translate to unit cell - precision

Don’t you think we could insert an optional offset to this method?

def translate2uc(..., offset=None):
    if isinstance(offset, float):
        d = np.ones(3) * offset
    elif isinstance(offset, list):
        d = np.array(offset)
    else:
        d = np.zeros(3)
    g = g.move(d)
    # do the existing stuff in this function
    g = g.move(-d)
    return g

I used this kind of shifts in two places in the geometries.

_Originally posted by @tfrederiksen in https://github.com/zerothi/sisl/issues/444#issuecomment-1059142958_

[zerothi]

I would really try to refrain from using these tolerances, because you’ll end up truncating positional data (depending on the tolerance levels). And this is not the way to go since you are effectively shifting relative positions which the routines says nothing about. Therefore documenting such a feature in translate2uc would be cumbersome and it wouldn’t be consistent. In fact, the move can be achieved with:

geom.move(1e-5).translate2uc().move(-1e-5)

there is no need for the array.

[zerothi]

Thanks for noticing!