Thanks for mentioning that, very useful! If you look in the numpy source you can begin to understand why the overheads are so large: for every operation it's f

Thanks for mentioning that, very useful! If you look in the numpy source you can begin to understand why the overheads are so large: for every operation it's first necessary to apply rules for broadcasting between different sizes and types, plus often being callable with a number of different function signatures (that includes __getitem__). And in many cases all of that is implemented in Python.