% liczenie entropii różnymi metodami
I = imread('cameraman.tif');
Ix = imread('circuit.tif');
Lpgm = imread('lena.pgm');
Lpgm30 = imread('lena30.pgm');
%losowe 
k = 10;  % variable range
n = 100;  % number of variables
x = ceil(k*rand(1,n));
y = ceil(k*rand(1,n));

% x = randi(k,1,n);  % need statistics toolbox
% y = randi(k,1,n);

disp('*** Entropy x, y ***');
Hx = entropy(x); fprintf('Hx = %.4f\n', Hx);
Hy = entropy(y); fprintf('Hy = %.4f\n', Hy);
disp('*** Entropy Lpgm i Lpgm30 ***');
Hpgm = entropy(Lpgm); fprintf('Hpgm = %.4f\n', Hpgm);
Hpgm30 = entropy(Lpgm30); fprintf('Hpgm30 = %.4f\n', Hpgm30);
disp('*** Joint entropy xy***:');
Hxy = jointEntropy(x,y); fprintf('Hxy = %.4f\n', Hxy);
disp('*** Conditional entropy x|y ***');
Hx_y = condEntropy(x,y); fprintf('Hx_y = %.4f\n', Hx_y);
disp('***  Mutual information x;y ***');
Ixy = mutInfo(x,y); fprintf('Ixy = %.4f\n', Ixy);
disp('*** Relative entropy (KL divergence) ***');
Dxy = relatEntropy(x,y); fprintf('Dxy = %.4f\n', Dxy);
disp('*** Normalized mutual information x;y ***');
nIxy = nmi(x,y); fprintf('nIxy = %.4f\n', nIxy);
disp('*** Nomalized variation information I_v(x,y) ***');
vIxy = nvi(x,y); fprintf('vIxy = %.4f\n', vIxy);
%% H(x|y) = H(x,y)-H(y)
i1 = isequalf(Hx_y,Hxy-Hy); 
%% I(x,y) = H(x)-H(x|y)
i2 = isequalf(Ixy,Hx-Hx_y);
%% I(x,y) = H(x)+H(y)-H(x,y)
i3 = isequalf(Ixy,Hx+Hy-Hxy);
%% I_n(x,y) = I(x,y)/sqrt(H(x)*H(y))
i4 = isequalf(nIxy,Ixy/sqrt(Hx*Hy));
%% I_v(x,y) = (1-I(x,y)/H(x,y))
i5 = isequalf(vIxy,1-Ixy/Hxy);
fprintf('efekty porównań: %d %d %d %d %d\n', i1,i2,i3,i4,i5);