scipy.cluster.hierarchy.num_obs_linkage#

scipy.cluster.hierarchy.num_obs_linkage(Z)[source]#

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

Parameters
Zndarray

The linkage matrix on which to perform the operation.

Returns
nint

The number of original observations in the linkage.

Examples

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

>>> 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]]

>>> Z = ward(pdist(X))

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

>>> num_obs_linkage(Z)
12