> In NumPy, AB works if A and B are both scalar. Or if A is 5×1×6 and B is 5×1×6×1. But not if A is 1×5×6 and B is 1×5×6×1. Huh?

> So, I removed it. In DumPy you can only do AB if one of A or B is scalar or A and B have exactly the same shape. That’s it, anything else raises an error. Instead, use indices, so it’s clear what you’re doing.

I also dislike the seemingly inconsistent adding of last axes with length 1.

I do like the capability that existing axes of length 1 will be broadcasted to any length of the other array in the operation, and use that all the time.

If I understand the text correctly, the author removed that as well.