/**
* Copyright (C) 2001-2017 by RapidMiner and the contributors
*
* Complete list of developers available at our web site:
*
* http://rapidminer.com
*
* This program is free software: you can redistribute it and/or modify it under the terms of the
* GNU Affero General Public License as published by the Free Software Foundation, either version 3
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without
* even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License along with this program.
* If not, see http://www.gnu.org/licenses/.
*/
package com.rapidminer.tools.math.similarity;
import com.rapidminer.example.Attribute;
import com.rapidminer.example.Example;
/**
* Abstract class that represents a bregman divergence.
*
* @author Regina Fritsch
*/
public abstract class BregmanDivergence extends DistanceMeasure {
private static final long serialVersionUID = 5886004923294334118L;
public double[] vectorSubtraction(Example x, double[] y) {
if (x.getAttributes().size() != y.length) {
throw new RuntimeException("Cannot substract vectors: incompatible numbers of attributes ("
+ x.getAttributes().size() + " != " + y.length + ")!");
}
double[] result = new double[x.getAttributes().size()];
int i = 0;
for (Attribute att : x.getAttributes()) {
result[i] = x.getValue(att) - y[i];
i++;
}
return result;
}
public double logXToBaseY(double number, double base) {
return Math.log(number) / Math.log(base);
}
@Override
public double calculateSimilarity(double[] value1, double[] value2) {
return -calculateDistance(value1, value2);
}
}