diff src/matlab/prune_corpus.m @ 0:c52bc3e8d3ad tip

user: boblsturm
branch 'default'
added README.md
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added data/.DS_Store
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added src/matlab/AnalysisCache.m
added src/matlab/CSS.m
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added src/matlab/nmf_beta.m
added src/matlab/nmf_divergence.m
added src/matlab/nmf_euclidean.m
added src/matlab/prune_corpus.m
added src/matlab/rot_kernel.m
added src/matlab/templateAdditionResynth.m
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--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/matlab/prune_corpus.m	Sun Jun 18 06:26:13 2017 -0400
@@ -0,0 +1,66 @@
+function [ Y, PrunedFrames, KeepCorpusFrames ] = prune_corpus( target, corpus, reduction_coef )
+
+    if reduction_coef == 1
+        Y = corpus;
+        PrunedFrames = [];
+        KeepCorpusFrames = [];
+        return;
+    end
+    [targetRows, targetCols]= size( target );
+    [corpusRows, corpusCols]= size( corpus );
+    
+    % Matrix: distances of every target frame to every other target frame
+    % i.e. Self-similarity matrix
+    TargetSelfSimMat = zeros(targetCols);
+    
+    % Matrix: distances of every target frame to every corpus frame
+    % Matrix( i, j ) = Similarity of corpus frame i to target frame j
+%     TargetToCorpSimMat = -1*ones(WCols, targetCols);
+    
+    % Calculate self-similarity of target (euclidean dist)
+    X2 = sum(target.^2,1);
+    TargetSelfSimMat = bsxfun(@plus,X2,X2')-2*(target'*target);
+%     TargetSelfSimMat = exp(-(1/10) * DistanceMat);
+    
+    % Calculate the distance between each corpus frame to first target
+    % frame
+    KeepCorpusFrames = [];
+    RemainingTargetFrames = 1:targetCols;
+    RemainingCorpusFrames = 1:corpusCols;
+    
+    while ~isempty(RemainingTargetFrames)
+        Dist = repmat(target(:,RemainingTargetFrames(1)),1, ...
+            length(RemainingCorpusFrames)) - corpus(:,RemainingCorpusFrames);
+        Distances = sum(Dist.^2,1);
+        % compute mean distances
+        meanDistance = mean(Distances);
+        
+        % find those corpus frames closer than reduction_coef of mean
+        idxcorpuskeep = Distances < reduction_coef*meanDistance;
+        KeepCorpusFrames = [KeepCorpusFrames RemainingCorpusFrames(idxcorpuskeep)];
+        
+        % find those target frames within twice that to next frame
+        distancetonext = TargetSelfSimMat(RemainingTargetFrames(1)+1,RemainingTargetFrames(1));
+        idxtarget = TargetSelfSimMat(RemainingTargetFrames,RemainingTargetFrames(1)) ...
+            < 2*distancetonext;
+        
+        if ~any( idxtarget ) && distancetonext == 0
+            idxtarget = RemainingTargetFrames(2);
+        end
+        
+        % shrink corpus
+        RemainingCorpusFrames = RemainingCorpusFrames(~idxcorpuskeep);
+        
+        % shrink target frames index
+        RemainingTargetFrames = RemainingTargetFrames(~idxtarget);
+        
+        fprintf( '%d remaining frames...\n', size( RemainingTargetFrames ) );
+    end
+    
+KeepCorpusFrames = sort( KeepCorpusFrames );
+Y = corpus( :, KeepCorpusFrames );
+PrunedFrames = setdiff( 1:corpusCols, KeepCorpusFrames );
+
+fprintf( 'Pruned %d frames...\n', size( PrunedFrames ) );
+
+end
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