issue_comments: 699548837

Interesting discussion #2217. As far as I understand, it solves a wider problem than using a tolerance on and a member by member comparison... but more complex to implement.

Here is the simple solution that works for me (combine.py:70):

        if not (all(index.equals(indexes[0]) for index in indexes[1:])
                or (tolerance > 0 and \
                    all(index.is_numeric() for index in indexes) and \
                    all(np.allclose(index, indexes[0], atol=tolerance, rtol=0) for index in indexes[1:]))):

I've not tested in depth, I can make a PR, tests, doc if you agree with this solution.

Regarding the name of the arg. "tolerance" is nice, but allclose has atol and rtol. My solution above only set atol, but both may be useful. Should we use: 2args: atol, rtol 2 args: atolerance, rtolerance 1 args: tolerance could be a number (->atol) or a tuple interpreted as atol, rtol = tolerance or a dict .... ?