JointDist

JOINTDIST
   Usage: [P bins] = JointDist(x,y,nbins)

This function calculates the joint distribution of the variables x and y.
It is simply a normalized histogram using hist3. nbins can take any form
of bins that hist3 can take, but no other hist3 options.

0001 function [P bins] = JointDist(x,y,nbins)
0002 
0003 %JOINTDIST
0004 %   Usage: [P bins] = JointDist(x,y,nbins)
0005 %
0006 %This function calculates the joint distribution of the variables x and y.
0007 %It is simply a normalized histogram using hist3. nbins can take any form
0008 %of bins that hist3 can take, but no other hist3 options.
0009 
0010 %Written by Dan Valente
0011 %October 2007
0012 
0013 %ensure x and y are both column matrices
0014 [nrowsx,ncolsx] = size(x);
0015 if (ncolsx ~= 1)
0016     x = x';
0017 end
0018 [nrowsy,ncolsy] = size(y);
0019 if (ncolsy ~= 1)
0020     y = y';
0021 end
0022 
0023 
0024 [H bins] = hist3([x y], nbins);
0025 N = sum(sum(H));
0026 binsize_x = bins{1}(3)-bins{1}(2);
0027 binsize_y = bins{2}(3)-bins{2}(2);
0028 P = H./(N*binsize_x*binsize_y);  %Normalize correctly
0029 
0030 
0031 return;
0032