No-one favours the pure Python version at the moment, because we're used to it being unworkably slow. In terms of the actual code, I do prefer pairwise_python i

No-one favours the pure Python version at the moment, because we're used to it being unworkably slow. In terms of the actual code, I do prefer pairwise_python in that example, because I can see roughly what's going on. pairwise_numpy is kind of like writing in Perl - it's short, but hard to understand. I use the SciPy stack, and I don't fully understand it. How does slicing a 2D array into three dimensions work?