/*
* RapidMiner
*
* Copyright (C) 2001-2011 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.tools.math.distribution.kernel;
import com.rapidminer.tools.math.distribution.EmpiricalNormalDistribution;
/**
* A normal kernel.
*
* @author Tobias Malbrecht
*/
public class NormalKernel extends EmpiricalNormalDistribution {
public static final long serialVersionUID = -320543538793918L;
private double minimumBandwidth;
public NormalKernel(double minimumBandwidth) {
super();
this.minimumBandwidth = minimumBandwidth;
}
@Override
protected void updateDistributionProperties() {
if (recentlyUpdated) {
mean = sum / totalWeightSum;
double stdDev = totalWeightSum > 1 ? Math.sqrt((squaredSum - sum * sum / totalWeightSum) / (totalWeightSum - 1)) : Double.MIN_VALUE;
standardDeviation = stdDev > minimumBandwidth ? stdDev : minimumBandwidth;
recentlyUpdated = false;
}
}
}