/*
* 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.function.window;
/**
* A gaussian window function.
*
* @author Tobias Malbrecht
*/
public class GaussianWindowFunction extends WindowFunction {
private double sigma;
public GaussianWindowFunction(Integer width, double sigma) {
super(width);
this.sigma = sigma;
}
public GaussianWindowFunction(Integer width, Integer justification) {
this(width, justification, 0.5d);
}
public GaussianWindowFunction(Integer width, Integer justification, double sigma) {
super(width, justification);
this.sigma = sigma;
}
@Override
protected double getValue(int width, int n) {
double term = (2 * n / (sigma * (width - 1))) - 1 / sigma;
return Math.exp(-0.5 * term * term);
}
}