/**
* 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.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;
standardDeviation = 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;
}
}
}