Repository /Debellor/debellor-1.0.jar:org.debellor.base.evaluator.score.Accuracy

/*
 *  Debellor
 *
 *  Copyright (C) 2008-2009 by Marcin Wojnarski
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU 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 General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program.  If not, see http://www.gnu.org/licenses/.
 */
package org.debellor.base.evaluator.score;

import org.debellor.core.DataObject;


/**
 * Calculates accuracy of a decision system (typically a classifier),
 * i.e. the fraction of samples for which predicted decision
 * was exactly the same as the target one.
 * 
 * @author Marcin Wojnarski
 *
 */
public class Accuracy extends Score {

	private int good;
	private int bad;
	
	
	public Accuracy() {
		reset();
	}

	@Override
	public void reset() {
		good = bad = 0;
	}

	@Override
	public void add(DataObject target, DataObject prediction) {
		if(target == null) return;
		if(prediction == null) {
			bad++;
			return;
		}
		if(target.equals(prediction))
			good++;
		else
			bad++;
	}
	
	@Override
	public String report() {
		double all = good + bad;
		if(all > 0) {
			double goodP = good / all * 100;
			double badP = bad / all * 100;
			return "Correctly classified:   " + good + "\t" + goodP + "%" + "\n" + 
			"Misclassified:          " + bad + "\t" + badP + "%";
		}
		else return "No test samples";
	}

	@Override
	public double result() {
		return good / (double) (good + bad);
	}

}