Poznámka:
Pairwise distance between pairs of objects
D = pdist(X) computes the Euclidean distance between pairs of objects in m-by-n data matrix X. Rows of X correspond to observations, and columns correspond to variables. D is a row vector of length m(m–1)/2, corresponding to pairs of observations in X. The distances are arranged in the order (2,1), (3,1), …, (m,1), (3,2), …, (m,2), …, (m,m–1)). D is commonly used as a dissimilarity matrix in clustering or multidimensional scaling.
Metrics
Given an m-by-n data matrix X, which is treated as m (1-by-n) row vectors x1, x2, …, xm, the various distances between the vector xs and xt are defined as follows: