ItakuraSaitoDistance.java example

Explorer
rapidminer-5-master
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package com.rapidminer.tools.math.similarity.divergences;

import com.rapidminer.example.Attribute;
import com.rapidminer.example.Attributes;
import com.rapidminer.example.Example;
import com.rapidminer.example.ExampleSet;
import com.rapidminer.example.Tools;
import com.rapidminer.operator.OperatorException;
import com.rapidminer.tools.math.similarity.BregmanDivergence;

/**
 * The "Itakura-Saito distance ".
 * 
 * @author Regina Fritsch
 */
public class ItakuraSaitoDistance extends BregmanDivergence {

	private static final long serialVersionUID = -931524423630316788L;

	@Override
	public double calculateDistance(double[] value1, double[] value2) {
		return (value1[0] / value2[0]) - Math.log((value1[0] / value2[0])) - 1;
	}

	@Override
	public void init(ExampleSet exampleSet) throws OperatorException {
	    super.init(exampleSet);
	    Tools.onlyNumericalAttributes(exampleSet, "value based similarities");
		Attributes attributes = exampleSet.getAttributes();
		if (attributes.size() != 1)
			throw new OperatorException("The bregman divergence you've choosen is not applicable for the dataset! Proceeding with the 'Squared Euclidean distance' bregman divergence.");
		for (Example example: exampleSet) {
			for (Attribute attribute: attributes) {
				if (example.getValue(attribute) <= 0) 
					throw new OperatorException("The bregman divergence you've choosen is not applicable for the dataset! Proceeding with the 'Squared Euclidean distance' bregman divergence.");;
			}
		}
	}

	@Override
	public String toString() {
		return "Itakura-Saito distance";
	}
}