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dboyliao/distance_matrix_trick_vectorized.py

Last active May 3, 2020 16:25
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distance_matrix_trick_vectorized.py
import numpy as np
def distance_vec(X):
# (x - y)^2 = x^2 + y^2 - 2xy
prod = -2 * X.dot(X.T)
sq = (X ** 2).sum(axis=-1)
return sq + sq[:, None] + prod
Raw
distance_matrix_trick_vectorized_v2.py
def distance_vec_v2(X):
# Thanks to Peter Cheng
diff = X[:, None, :] - X[None, :, :]
return (diff ** 2).sum(axis=-1) ** 0.5
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