Inconsistency with equation (8) (possible missing division by M-1)

[valeria-a]

Hi! First of all, I want to thank you for a great library - it saved me a lot of time! I noticed that when you calculate center_except in similarity(), you follow equation (8) from the article which actually calculates mean of all the elements except one, so there should be summation and division by M-1. I see you perform the summation and subtraction of relevant element, however there is no division by M-1. Is there a chance it is missing? Thanks!