Why `divmod(float('inf'), 1) == (float('nan'), float('nan'))`

[Chris Angelico]

On Thu, Sep 18, 2014 at 1:16 AM, cool-RR <ram.rachum at gmail.com> wrote:
> I didn't ask for the modulo, I agree it should remain NaN. I'm talking about the floor division.
>

Invariant: div*y + mod == x.

If mod is NaN, there is no possible value for div that will make the
invariant true, ergo it too has to be NaN.

ChrisA