HISTO3 calculates histogram for multiple columns with common bin values 
    among all data columns, and can be useful for data compression. 

 R = HISTO3(Y)
 R = HISTO3(Y, W)
	Y	data
	W	weight vector containing weights of each sample, 
		number of rows of Y and W must match.
		default W=[] indicates that each sample is weighted with 1. 
 	R 	struct with these fields 
       R.X  	the bin-values, bin-values are equal for each channel
		thus R.X is a column vector. If bin values should 
		be computed separately for each data column, use HISTO2
       R.H  	is the frequency of occurence of value X 
  	R.N  	are the number of valid (not NaN) samples 

 Data compression can be performed in this way
   	[R,tix] = histo3(Y) 
      		is the compression step

	R.tix provides a compressed data representation. 
	R.compressionratio estimates the compression ratio

 	R.X(tix) and R.X(R.tix) 
		reconstruct the orginal signal (decompression) 

 The effort (in memory and speed) for compression is O(n*log(n)).
 The effort (in memory and speed) for decompression is O(n) only. 

 see also: HISTO, HISTO2, HISTO3, HISTO4

Package: nan