Agglomerative clustering algorithm Most popular hierarchical clustering technique Basic algorithm 1. Compute the distance matrix between the input data points 2. Let each data point be a cluster 3. Repeat Merge the two closest clusters Update the distance matrix 6. Until only a single cluster remains Key operation is the computation of the distance between two clusters e Different definitions of the distance between clusters lead to different algorithmsAgglomerative clustering algorithm ◼ Most popular hierarchical clustering technique ◼ Basic algorithm 1. Compute the distance matrix between the input data points 2. Let each data point be a cluster 3. Repeat 4. Merge the two closest clusters 5. Update the distance matrix 6. Until only a single cluster remains ◼ Key operation is the computation of the distance between two clusters ◆ Different definitions of the distance between clusters lead to different algorithms