function [S, mu, sigma2] = standardize(M, mu, sigma2)% function S = standardize(M, mu, sigma2)% Make each column of M be zero mean, std 1.% Thus each row is scaled separately.%% If mu, sigma2 are omitted, they are computed from Mif nargin < 2  mu = mean(M,2);  sigma2 = std(M,0,2);  sigma2 = sigma2 + eps*(sigma2==0);end[nrows ncols] = size(M);S = M - repmat(mu(:), [1 ncols]);S = S ./ repmat(sigma2, [1 ncols]);