Euclidean distance

[Emma1066]

Hi, thanks for sharing this greate project！
There is one line of code I can't understand:
rmse = (sum(map(lambda x: x**2, differences)) / len(differences))**0.5
As far as I know, if x and y are two points in n-dimension space, the euclidean distance between them is

d(x,y) = sqrt((x1-y1)^2 + (x2-y2)^2 + ... + (xn-yn)^2)

So why in the code the sum term is divided by len(differences) ?
Thanks a lot if you could help me.

[leohill33]

I have the same question. Isn't the euclidean distance between (1,1), (2,2) supposed to be √2？ :目

[damjankuznar]

Because this is not actually euclidean distance, but rather root mean square error (RMSE). See here https://en.wikipedia.org/wiki/Root-mean-square_deviation
Does that answer your question?

[leohill33]

Because this is not actually euclidean distance, but rather root mean square error (RMSE). See here https://en.wikipedia.org/wiki/Root-mean-square_deviation
Does that answer your question?

Got it. Thank you so much for your work on explaining how LOF works. :)