Single-linkage clustering

One of the simplest agglomerative hierarchical clustering method is single linkage,also known as the nearest neighbor technique.The defining feature of the method is that distance between groups is defined as the distance between the closest pair of objects, where only pairs consisting of one object from each group are considered[1].

Single linkage clustering defines the distance between two clusters as the minimal distance of any two objects belonging two different clusters http://homepages.inf.ed.ac.uk/rbf/CVonline/LOCAL_COPIES/CANTZLER2/clustering.pdf].