Update to work on ppc64le

[piotrmaslanka]

Since on POWER the input of abs() is promoted to an integer (or the result is), this condition always holds. This is a fix that hopefully makes it work on ppc64le, this was verified to work on ppc64le and returns valid results.

I've filed a concurrent pull request for OpenSfM itself, but it seems like they certainly do take their time...

[pierotofy]

Thanks @piotrmaslanka ✋

You are probably not fixing the issue though, since eps (epsilon) is generally a very small floating value. The proper fix would be to change this to fabs? See https://stackoverflow.com/questions/33738509/whats-the-difference-between-abs-and-fabs

If the compiler is using the int version of abs, then you're just comparing num > 0 && num < 0, which is not the correct logic.