histo4

 HISTO4 calculates histogram for rows and supports data compression

 R = HISTO4(Y)
     R is a struct with th fields 
       R.X  are the bin-values 
       R.H  is the frequency of occurence of value X 
      R.N  are the number of samples 

 HISTO4 might be useful for data compression, because
 [R,tix] = histo4(Y) 
         is the compression step
 R.X(tix,:) 
      is the decompression step

 The effort (in memory and speed) for compression is O(n*log(n))
 The effort (in memory and speed) for decompression is only O(n)
 
 see also: HISTO, HISTO2, HISTO3, HISTO4

 REFERENCE(S):
  C.E. Shannon and W. Weaver 'The mathematical theory of communication' University of Illinois Press, Urbana 1949 (reprint 1963).