[Python-Dev] PEP 465: A dedicated infix operator for matrix multiplication

[Björn Lindqvist]

2014-04-07 3:41 GMT+02:00 Nathaniel Smith <njs at pobox.com>:
> So, I guess as far as I'm concerned, this is ready to go. Feedback welcome:
>   http://legacy.python.org/dev/peps/pep-0465/

Couldn't you please have made your motivation example actually runnable?

import numpy as np
from numpy.linalg import inv, solve

# Using dot function:
S = np.dot((np.dot(H, beta) - r).T,
           np.dot(inv(np.dot(np.dot(H, V), H.T)), np.dot(H, beta) - r))

# Using dot method:
S = (H.dot(beta) - r).T.dot(inv(H.dot(V).dot(H.T))).dot(H.dot(beta) - r)

Don't keep your reader hanging! Tell us what the magical variables H,
beta, r and V are. And why import solve when you aren't using it?
Curious readers that aren't very good at matrix math, like me, should
still be able to follow your logic. Even if it is just random data,
it's better than nothing!


-- 
mvh/best regards Björn Lindqvist