mutualinfo(x, y,nBins, ifplot)

% Calculate the mutual information between x and y using the simple histogram method.
% Jeffrey-Perks law is assumed (adding 0.5 to all cells before MI estimation).
% Usage: MI = mutualinfo(x, y,nBins, ifplot)
% 'nBins' : number of bins for each dimension.
% mutual informaiton: I(X;Y) = sum(sum(p(x,y)*log(p(x,y)/p(x)p(y)))
% See "Information Theory" (Shannon, 1948)
% This code is inspired by:
% Iskarous, K., Mooshammer, C., Hoole, P., Recasens,
% D., Shadle, C. H., Saltzman, E., and Whalen, D. H. (2013).
% "The coarticulation/invariance scale: Mutual information
% as a measure of coarticulation resistance, motor synergy,
% and articulatory invariance," J. Acoust. Soc. Am. 134, 1271-1282.
%
% Requirement: "hist3" in Statistics and Machine Learning Toolbox