Numpy Broadcast to perform euclidean distance vectorized

Question

I have matrices that are 2 x 4 and 3 x 4. I want to find the euclidean distance across rows, and get a 2 x 3 matrix at the end. Here is the code with one for loop that compu

Answer 1

Using numpy.linalg.norm also works well with broadcasting. Specifying an integer value for axis will use a vector norm, which defaults to Euclidean norm.

import numpy as np

a = np.array([[1,1,1,1],[2,2,2,2]])
b = np.array([[1,2,3,4],[1,1,1,1],[1,2,1,9]])
np.linalg.norm(a[:, np.newaxis] - b, axis = 2)

# array([[ 3.74165739,  0.        ,  8.06225775],
#       [ 2.44948974,  2.        ,  7.14142843]])