VSM - Applies the Vector Space Model to a document collection
    [SC, DOCS_INDS] = VSM(D, Q, NORMALIZE_DOCS) applies the 
    Vector Space Model to the text collection represented by 
    the term - document matrix D for the query defined by the 
    vector Q [1]. NORMALIZE_DOCS defines if the document 
    vectors are to be normalized (1) or not (0). SC contains 
    the sorted similarity coefficients, while DOC_INDS contains 
    the corresponding document indices.
 
    REFERENCES: 
    [1] M.Berry and M.Browne, Understanding Search Engines, 
    Mathematical Modeling and Text Retrieval, Philadelphia, 
    PA: Society for Industrial and Applied Mathematics, 1999.
 
  Copyright 2011 Dimitrios Zeimpekis, Eugenia Maria Kontopoulou, 
                 Efstratios Gallopoulos