X-lanni
46 lines
1.7 KiB
Matlab
46 lines
1.7 KiB
Matlab
function likelihood = computeLikelihood(sign, memory, dictionary)
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%GETLIKELIHOOD Compute the likelihood of the signature sign.
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% likelihood = getLikelihood(sign, memory, dictionary)
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%
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% Mem : the memory (Mem = [signId1 WordRefIds...; signId2 WordRefIds...; ...])
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% Dict : the visual words dictionary (Dict = [wordId1 SignRefIds...;
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% wordId2 SignRefIds...; ...])
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% sign : The signature reference which we want the likelihood with all
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% others in the memory (sign = [id wordsRef...])
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likelihood = zeros(size(memory,1),1);
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nwi = 0; % nwi is the number of a specific word referenced by a place
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ni = 0; % ni is the total of words referenced by a place
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nw = 0; % nw is the number of places referenced by a specific word
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N = 0; % N is the total number of places
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N = size(memory,1);
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words = unique(sign(2:end));
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for i=1:length(words)
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if words(i) ~= 0
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% "Inverted index" - For each places referenced by the word
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refs = unique(dictionary(find(dictionary(:,1) == words(i),1), 2:end));
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refs = refs(refs~=0);
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nw = 0;
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for j=1:length(refs)
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nw = nw + 1;
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end
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logNnw = log10(N/nw); % TODO : division by 0 (not supposed to occur)
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if logNnw ~= 0
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for j=1:length(refs)
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pos = find(memory(:,1) == refs(j),1);
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sign = memory(pos, :);
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nwi = sum(sign(2:end) == words(i));
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ni = sum(sign(2:end)>0);
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if ni ~= 0
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likelihood(pos) = likelihood(pos) + ( nwi * logNnw ) / ni;
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end
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end
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end
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end
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end |