pyp = histogram(y,bins);
    py = pyp.Values/length;
    hy = - sum(py .* log(py+1e-8));

matlab 绘制2d的直方图

pxyp = histogram2(x,y,bins);
pxy = pxyp.Values/length;
hxy = - sum(sum(pxy .* log(pxy+1e-8)));

%% 计算互信息的函数
function ixy = calMIMatlab(x,y)
    length = size(x,2);
    bins = 100 ;
    pxp = histogram(x, bins);
    px = pxp.Values/length;
    hx = - sum(px .* log(px+1e-8));

    pyp = histogram(y,bins);
    py1 = pyp.Values/length;
    hy = - sum(py1 .* log(py1+1e-8));

    pxyp = histogram2(x,y,bins);
    pxy = pxyp.Values/length;
    hxy = - sum(sum(pxy .* log(pxy+1e-8)));

    ixy = hx + hy - hxy;
end