Mercurial > hg > camir-aes2014
diff core/magnatagatune/sim_from_comparison_naive.m @ 0:e9a9cd732c1e tip
first hg version after svn
author | wolffd |
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date | Tue, 10 Feb 2015 15:05:51 +0000 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/core/magnatagatune/sim_from_comparison_naive.m Tue Feb 10 15:05:51 2015 +0000 @@ -0,0 +1,73 @@ +function [sim, dissim, confidence] = sim_from_comparison_naive(comparison, comparison_ids, symmetrical) +% +% [sim, dissim, confidence] = sim_from_comparison_naive(comparison) +% +% derives symmetric, absolute similarity measurements +% from relative magnatagatune comparisons +% naive implementation for first tests of the ITML algorithm +% + +% reindex comparison for more simple evaluation +% makro_prepare_comparison + +% --- +% analyse the number of comparisons for each pair of songs +% --- +[num_compares] = get_comparison_stats(comparison, comparison_ids); + +% --- +% in comparison, the outlying piece is highlighted. +% thus, we naively consider that +% a. both of the remaining pieces are more similar to each other. +% b. the outlier is dissimilar to both of the other pieces +% --- +[outsort, outidx] = sort(comparison(:,4:6),2,'ascend'); + +% --- +% similarity of the two non-outliers a, b +% they are similar if both of them have scores way smaller +% than the outlier c: +% score (a,b) = 1 - (max(a,b)/c) +% +% dissimilarity: clip b is considered more different to clip c than +% a, as clip a seems to share some properties with both songs +% dissim(b,c) = 0.5 + b/(2c) +% --- + +sim = sparse(numel(comparison_ids),numel(comparison_ids)); +dissim = sparse(numel(comparison_ids),numel(comparison_ids)); +for i = 1:size(comparison,1) + + % get the outlier votes + simpair = comparison(i,outidx(i,1:2)); + c = comparison(i,outidx(i,3)); + + % we want a triangular similarity matrix + [simpair, simidx] = sort(simpair); + outsort(i,1:2) = outsort(i,simidx); + + % --- + % save the distance between the second biggest vote and the max vote. + % NOTE: we bias the vote by dividing through the number of total + % comparisons for the particular pair of clips + % --- + sim(simpair(1), simpair(2)) = sim(simpair(1), simpair(2)) + ... + (1 - outsort(i,2) / outsort(i,3)) * (1 / num_compares(simpair(1),simpair(2))); + + dissim(simpair(1:2), c) = 0.5 + (outsort(i,1:2) ./ (2 * outsort(i,3))); +end + +% --- +% mirror to make matrix symmetrical +% --- +if nargin == 3 && symmetrical + sim = sim + sim'; + dissim = dissim + dissim'; +end + +% --- +% TODO: use number of votes and std or similar to +% rate the confidence for each similarity mesurement +% --- +confidence = []; +