1. Intro to Hierarchical Clustering

<aside> 💡 Hierarchical clustering algorithms build a hierarchy of clusters where each node is a cluster consists of the clusters of its daughter nodes.

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Hierarchicall clustering

Agglomerative clustering

2. More on Hierarchical Clustering

Agglomerative Algorithm

1. Create n clusters, one for each data point
2. Compute the Proximity Matrix
3. Repeat
   1. Merge the two closest clusters
   2. Update the proximity matrix
4. Until only a single cluster remains

Distance between clusters

1. Single-Linkage Clustering
   • Minimum distance between clusters
2. Complete-Linkage Clustering
   • Maximum distance between clusters
3. Average-Linkage Clustering
   • Average distance between clusters
4. Centroid-Linkage Clustering
   • Distance between cluster centroids

Advantages vs. Disadvantages

Hierarchical clustering vs. K-Means