/*
* 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.example;
import com.rapidminer.tools.LogService;
/** Attribute statistics object for numerical attributes.
*
* @author Ingo Mierswa
* @version $Id: NumericalStatistics.java,v 1.7 2008/05/25 12:08:46 ingomierswa Exp $
*/
public class NumericalStatistics implements Statistics {
private static final long serialVersionUID = -6283236022093847887L;
private double sum = 0.0d;
private double squaredSum = 0.0d;
private int valueCounter = 0;
public NumericalStatistics() {}
/** Clone constructor. */
private NumericalStatistics(NumericalStatistics other) {
this.sum = other.sum;
this.squaredSum = other.squaredSum;
this.valueCounter = other.valueCounter;
}
public Object clone() {
return new NumericalStatistics(this);
}
public void startCounting(Attribute attribute) {
this.sum = 0.0d;
this.squaredSum = 0.0d;
this.valueCounter = 0;
}
public void count(double value) {
if (!Double.isNaN(value)) {
sum += value;
squaredSum += value * value;
valueCounter++;
}
}
public boolean handleStatistics(String name) {
return
AVERAGE.equals(name) ||
VARIANCE.equals(name) ||
SUM.equals(name);
}
public double getStatistics(Attribute attribute, String name, String parameter) {
if (AVERAGE.equals(name)) {
return this.sum / this.valueCounter;
} else if (VARIANCE.equals(name)) {
double average = this.sum / this.valueCounter;
return squaredSum / valueCounter - (average * average);
} else if (SUM.equals(name)) {
return this.sum;
} else {
LogService.getGlobal().log("Cannot calculate statistics, unknown type: " + name, LogService.WARNING);
return Double.NaN;
}
}
}