We have a first pull request. Badly formed though. @Zelenyi wants multi-dimensional histograms which are used quite frequently in particle physics. Does someone have the similar experience?

In some cases more. Yes numpy is a reference. And I compared performance with it.

it looks like there is some looping and several numpy calls on the python side, so I would expect ROOT to be faster.

I know numpy implementation. There are some question to it. Most of all, what we actually want. It is just a curious cases where it very important to know what you want to achieve.