I must have fallen asleep at the reviewing wheel. You've got precision and recall the wrong way around, which means I didn't hand-check your tests. It should have been more obvious than to hand-check: for the label indicator matrix examples, recall is 1 for all but 'samples' where precision is < 1).

And a few lines on, you square `beta2` which is already `beta ** 2`.

Could you please fix these, @arjoly?