Calculates the cluster silhouette scores

Calculates the Silhouette in Rust given the original data and a membership vector. a(i) and b(i) are mean squared Euclidean distances, which keeps the whole thing closed-form and avoids materialising any pairwise distance. The trade-off is that the scores are not the numbers a plain-Euclidean silhouette gives: squaring inflates b more than a, so the values run higher. The sign is unaffected, so which points sit in the wrong cluster is the same call, but do not compare the magnitudes against implementations that use plain Euclidean.

Usage

rs_silhouette_score(data, cluster_membership)

Arguments

data

Numeric matrix. The data in shape of sample x features.

cluster_membership

Integers. Cluster memberships as integers.

Value

A list with the following items

• mean_silhouette - Mean silhouette scores per cluster.

• silhouette_scores - Silhouette scores per given data point.