<Dd> Recommender systems are designed to recommend new items based on a user's tastes . They sometimes use clustering algorithms to predict a user's preferences based on the preferences of other users in the user's cluster . </Dd> <Dt> Markov chain Monte Carlo methods </Dt> <Dd> Clustering is often utilized to locate and characterize extrema in the target distribution . </Dd> <Dd> Anomalies / outliers are typically - be it explicitly or implicitly - defined with respect to clustering structure in data . </Dd>

How is the ratio measure in clustering output calculated