function [L,C] = kmeans(X,k) KMEANS Cluster multivariate data using the k-means++ algorithm. [L,C] = kmeans(X,k) produces a 1-by-size(X,2) vector L with one class label per column in X and a size(X,1)-by-k matrix C containing the centers

GMM dynamic panel estimation as in Arellano et Bond (1991) Review of Economic Studies 58, p 277-297