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