wehub-resource-sync
22 lines
559 B
Matlab
Executable File
22 lines
559 B
Matlab
Executable File
function z = jointEntropy(x, y)
|
|
% Compute joint entropy z=H(x,y) of two discrete variables x and y.
|
|
% Input:
|
|
% x, y: two integer vector of the same length
|
|
% Output:
|
|
% z: joint entroy z=H(x,y)
|
|
% Written by Mo Chen (sth4nth@gmail.com).
|
|
assert(numel(x) == numel(y));
|
|
n = numel(x);
|
|
x = reshape(x,1,n);
|
|
y = reshape(y,1,n);
|
|
|
|
l = min(min(x),min(y));
|
|
x = x-l+1;
|
|
y = y-l+1;
|
|
k = max(max(x),max(y));
|
|
|
|
idx = 1:n;
|
|
p = nonzeros(sparse(idx,x,1,n,k,n)'*sparse(idx,y,1,n,k,n)/n); %joint distribution of x and y
|
|
|
|
z = -dot(p,log2(p));
|
|
z = max(0,z); |