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Hands-On Unsupervised Learning with Python
book

Hands-On Unsupervised Learning with Python

by Giuseppe Bonaccorso
February 2019
Intermediate to advanced content levelIntermediate to advanced
386 pages
9h 54m
English
Packt Publishing
Content preview from Hands-On Unsupervised Learning with Python

Silhouette score

The most common method to assess the performance of a clustering algorithm without knowledge of the ground truth is the silhouette score. It provides both a per-sample index and a global graphical representation that shows the level of internal coherence and separation of the clusters. In order to compute the score, we need to introduce two auxiliary measures. The first one is the average intra-cluster distance of a sample xi ∈ Kj assuming the cardinality of |Kj| = n(j):

For K-means, the distance is assumed to be Euclidean, but there are no specific limitations. Of course, d(•) must be the same distance function employed in ...

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Publisher Resources

ISBN: 9781789348279Supplemental Content