/*
* RapidMiner
*
* Copyright (C) 2001-2008 by Rapid-I and the contributors
*
* Complete list of developers available at our web site:
*
* http://rapid-i.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.operator.learner.tree;
import com.rapidminer.example.Attribute;
import com.rapidminer.example.Example;
import com.rapidminer.example.ExampleSet;
import com.rapidminer.example.set.SplittedExampleSet;
/**
* This criterion class can be used for the incremental calculation of benefits.
*
* @author Sebastian Land
* @version $Id: AbstractCriterion.java,v 1.5 2008/05/09 19:22:52 ingomierswa Exp $
*/
public abstract class AbstractCriterion implements Criterion {
// data for incremental calculation
protected double leftWeight;
protected double rightWeight;
protected double totalWeight;
protected double[] totalLabelWeights;
protected double[] leftLabelWeights;
protected double[] rightLabelWeights;
protected Attribute labelAttribute;
protected Attribute weightAttribute;
public abstract double getBenefit(SplittedExampleSet exampleSet);
public boolean supportsIncrementalCalculation() {
return false;
}
public void startIncrementalCalculation(ExampleSet exampleSet) {
FrequencyCalculator calculator = new FrequencyCalculator();
rightLabelWeights = calculator.getLabelWeights(exampleSet);
leftLabelWeights = new double[rightLabelWeights.length];
totalLabelWeights = new double[rightLabelWeights.length];
System.arraycopy(rightLabelWeights, 0, totalLabelWeights, 0, rightLabelWeights.length);
leftWeight = 0;
rightWeight = calculator.getTotalWeight(totalLabelWeights);
totalWeight = rightWeight;
labelAttribute = exampleSet.getAttributes().getLabel();
weightAttribute = exampleSet.getAttributes().getWeight();
}
public void swapExample(Example example) {
double weight = 1;
if (weightAttribute != null) {
weight = example.getValue(weightAttribute);
}
int label = (int)example.getValue(labelAttribute);
leftWeight += weight;
rightWeight -= weight;
leftLabelWeights[label] += weight;
rightLabelWeights[label] -= weight;
}
public double getIncrementalBenefit() {
return 0;
}
}