annotate toolboxes/FullBNT-1.0.7/KPMstats/multinomial_sample.m @ 0:cc4b1211e677 tip

initial commit to HG from Changeset: 646 (e263d8a21543) added further path and more save "camirversion.m"
author Daniel Wolff
date Fri, 19 Aug 2016 13:07:06 +0200
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Daniel@0 1 function Y = sample_cond_multinomial(X, M)
Daniel@0 2 % SAMPLE_MULTINOMIAL Sample Y(i) ~ M(X(i), :)
Daniel@0 3 % function Y = sample_multinomial(X, M)
Daniel@0 4 %
Daniel@0 5 % X(i) = i'th sample
Daniel@0 6 % M(i,j) = P(Y=j | X=i) = noisy channel model
Daniel@0 7 %
Daniel@0 8 % e.g., if X is a binary image,
Daniel@0 9 % Y = sample_multinomial(softeye(2, 0.9), X)
Daniel@0 10 % will create a noisy version of X, where bits are flipped with probability 0.1
Daniel@0 11
Daniel@0 12 if any(X(:)==0)
Daniel@0 13 error('data must only contain positive integers')
Daniel@0 14 end
Daniel@0 15
Daniel@0 16 Y = zeros(size(X));
Daniel@0 17 for i=min(X(:)):max(X(:))
Daniel@0 18 ndx = find(X==i);
Daniel@0 19 Y(ndx) = sample_discrete(M(i,:), length(ndx), 1);
Daniel@0 20 end
Daniel@0 21
Daniel@0 22