`scipy.cluster.hierarchy._hierarchy_impl:num_obs_linkage`

Signature

def num_obs_linkage(Z)

Return the number of original observations of the linkage matrix passed.

from scipy.cluster.hierarchy import ward, num_obs_linkage
from scipy.spatial.distance import pdist

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X = [[0, 0], [0, 1], [1, 0],
     [0, 4], [0, 3], [1, 4],
     [4, 0], [3, 0], [4, 1],
     [4, 4], [3, 4], [4, 3]]

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Z = ward(pdist(X))

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``Z`` is a linkage matrix obtained after using the Ward clustering method with ``X``, a dataset with 12 data points.

num_obs_linkage(Z)

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