1 files changed, 58 insertions, 0 deletions
diff --git a/FEAST/FSToolbox/FCBF.m b/FEAST/FSToolbox/FCBF.m
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+function [selectedFeatures] = FCBF(featureMatrix,classColumn,threshold)
+%function [selectedFeatures] = FCBF(featureMatrix,classColumn,threshold)
+%
+%Performs feature selection using the FCBF measure by Yu and Liu 2004.
+%
+%Instead of selecting a fixed number of features it provides a relevancy threshold and selects all
+%features which score above that and are not redundant
+%
+% The license is in the license.txt provided.
+
+numFeatures = size(featureMatrix,2);
+classScore = zeros(numFeatures,1);
+
+for i = 1:numFeatures
+    classScore(i) = SU(featureMatrix(:,i),classColumn);
+end
+
+[classScore indexScore] = sort(classScore,1,'descend');
+
+indexScore = indexScore(classScore > threshold);
+classScore = classScore(classScore > threshold);
+
+if ~isempty(indexScore)
+    curPosition = 1;
+else
+    curPosition = 0;
+end
+    
+while curPosition <= length(indexScore)
+    j = curPosition + 1;
+    curFeature = indexScore(curPosition);
+    while j <= length(indexScore)
+        scoreij = SU(featureMatrix(:,curFeature),featureMatrix(:,indexScore(j)));
+        if scoreij > classScore(j)
+            indexScore(j) = [];
+            classScore(j) = [];
+        else
+            j = j + 1;
+        end
+    end
+    curPosition = curPosition + 1;
+end
+
+selectedFeatures = indexScore;
+
+end
+
+function [score] = SU(firstVector,secondVector)
+%function [score] = SU(firstVector,secondVector)
+%
+%calculates SU = 2 * (I(X;Y)/(H(X) + H(Y)))
+
+hX = h(firstVector);
+hY = h(secondVector);
+iXY = mi(firstVector,secondVector);
+
+score = (2 * iXY) / (hX + hY);
+end