function ratios = computeLikelihoodRatios(sample,step)
% COMPUTELIKELIHOODRATIOS computes the likelyhood ratios
% each of the models M in {M1,M2,M3} for subsets of the
% sample in steps of 'step' size and returns them as
% a matrix of rows where each row is like:
%
% row = [M1/M2 M1/M3 M2/M3];

ratios = [];
sz = size(sample);
t = [0; 0; 0];

for i = 1:sz(1)
    % compute P of current event occuring
    p = probOfEvent(sample(i,1:sz(2)));
    
    % multiply ratios by totals
    t = [t(1) + log(p(1));
         t(2) + log(p(2));
         t(3) + log(p(3))];
    
    % if step add to results
    if mod(i,step) == 0
        rsz = size(ratios);
        ratios(rsz(1)+1, 1:3) = [t(1) - t(2); t(1) - t(3); t(2) - t(3)];
    end
end