[luispedrocoelho]

1. No, that function was the bottleneck, by far, and I can tell you that >10,000x was what we got between the initial version and the final one.

2. I don't care about faster at this point. The function is fast enough. Maybe there is some magic incantation of pandas that will be readable and compute the same values, but I will believe it when I see it. What I thought was more idiomatic was much slower.

I think this is more of a case of "the problem does not fit numpy/pandas' structure (because of how the duplicated indices need to be handled), so you end up with ugly code."

[joshuamorton]

1. you don't get 10000x speedups by changing languages. It's likely that this optimization would be necessary in any case.

2. You don't care about improving the code, but you did care enough to write an article saying that the language didn't fit your needs without actually doing the due diligence to check and see if the language fit your needs. That's the part that gets me.