Cluster analysis (CA) is an exploratory data analysis set of tools and algorithms that aims at classifying different objects into groups in a way that the similarity between two objects is maximal if they belong to the same group and minimal otherwise. In biology, CA is an essential tool for taxonomy of plants, animals, or other specimens. In clinical medicine, it can be used to identify patients who have diseases with a common cause, or patients who should receive the same treatment or who should have the same level of response to treatment. In epidemiology, CA has many uses, such as finding meaningful conglomerates of regions, communities, or neighborhoods with similar epidemiological profiles, when many variables are involved and natural groupings do not exist. In ...