samer@4: function [Y,Z]=stochastic1(X),
samer@4: % stochastic1 - make columns sum to one (like probabilities)
samer@4: %
samer@4: % stochastic1 :: [[N,M]] -> [[N,M]], [[M]].
samer@4: %
samer@4: % optionally returns the column sums as well. 
samer@4: % NOTE: this function assumes that X contains no NaNs and
samer@4: % at most one Inf per column. Eg, the function will map
samer@4: %
samer@4: % [2;3;6;Inf;1;8] -> [0;0;0;1;0;0]
samer@4: %
samer@4: % See also: the function stochastic works on ROWS not columns.
samer@4: 
samer@4: 
samer@4: Z=sum(X,1);
samer@4: 
samer@4: Y=X./repmat(max(Z,realmin),size(X,1),1);
samer@4: 
samer@4: % any nans are assumed to be inf/inf so are replaced with 1
samer@4: Y(isnan(Y))=1;
samer@4: