CM - computes a rank-L approximation of the input matrix 
  using the Centroids Method [1]
    [X, Y]=CM(A, CLUSTERS) computes the rank-K approximation 
    X*Y of the input matrix A with the Centroids Method [1], 
    using the cluster structure information from CLUSTERS.
 
    REFERENCES: 
    [1] H. Park, M. Jeon, and J. Rosen. Lower Dimensional Representation
    of Text Data Based on Centroids and Least Squares.
    BIT Numerical Mathematics, 43(2):427–448, 2003.
 
  Copyright 2011 Dimitrios Zeimpekis, Eugenia Maria Kontopoulou, 
                 Efstratios Gallopoulos