sklearn.metrics.pairwise
.euclidean_distances¶

sklearn.metrics.pairwise.
euclidean_distances
(X, Y=None, Y_norm_squared=None, squared=False)[source]¶ Considering the rows of X (and Y=X) as vectors, compute the distance matrix between each pair of vectors.
For efficiency reasons, the euclidean distance between a pair of row vector x and y is computed as:
dist(x, y) = sqrt(dot(x, x)  2 * dot(x, y) + dot(y, y))
This formulation has two advantages over other ways of computing distances. First, it is computationally efficient when dealing with sparse data. Second, if x varies but y remains unchanged, then the rightmost dot product dot(y, y) can be precomputed.
However, this is not the most precise way of doing this computation, and the distance matrix returned by this function may not be exactly symmetric as required by, e.g.,
scipy.spatial.distance
functions.Parameters: X : {arraylike, sparse matrix}, shape (n_samples_1, n_features)
Y : {arraylike, sparse matrix}, shape (n_samples_2, n_features)
Y_norm_squared : arraylike, shape (n_samples_2, ), optional
Precomputed dotproducts of vectors in Y (e.g.,
(Y**2).sum(axis=1)
)squared : boolean, optional
Return squared Euclidean distances.
Returns: distances : {array, sparse matrix}, shape (n_samples_1, n_samples_2)
See also
paired_distances
 distances betweens pairs of elements of X and Y.
Examples
>>> from sklearn.metrics.pairwise import euclidean_distances >>> X = [[0, 1], [1, 1]] >>> # distance between rows of X >>> euclidean_distances(X, X) array([[ 0., 1.], [ 1., 0.]]) >>> # get distance to origin >>> euclidean_distances(X, [[0, 0]]) array([[ 1. ], [ 1.41421356]])