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package de.lmu.ifi.dbs.elki.utilities.scaling;
/*
This file is part of ELKI:
Environment for Developing KDD-Applications Supported by Index-Structures
Copyright (C) 2015
Ludwig-Maximilians-Universität München
Lehr- und Forschungseinheit für Datenbanksysteme
ELKI Development Team
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/>.
*/
import de.lmu.ifi.dbs.elki.utilities.optionhandling.AbstractParameterizer;
import de.lmu.ifi.dbs.elki.utilities.optionhandling.OptionID;
import de.lmu.ifi.dbs.elki.utilities.optionhandling.parameterization.Parameterization;
import de.lmu.ifi.dbs.elki.utilities.optionhandling.parameters.DoubleParameter;
/**
* Non-linear scaling function using a Gamma curve.
*
* @author Erich Schubert
* @author Remigius Wojdanowski
* @since 0.3
*/
public class GammaScaling implements StaticScalingFunction {
/**
* OptionID for the gamma value.
*/
public static final OptionID GAMMA_ID = new OptionID("scaling.gamma", "Gamma value for scaling.");
/**
* Gamma value.
*/
private double gamma;
/**
* Constructor without options.
*/
public GammaScaling() {
this(1.0);
}
/**
* Constructor with Gamma value.
*
* @param gamma Gamma value.
*/
public GammaScaling(double gamma) {
this.gamma = gamma;
}
@Override
public double getScaled(double d) {
return Math.pow(d, gamma);
}
@Override
public double getMin() {
return Double.NEGATIVE_INFINITY;
}
@Override
public double getMax() {
return Double.POSITIVE_INFINITY;
}
/**
* Parameterization class.
*
* @author Erich Schubert
*
* @apiviz.exclude
*/
public static class Parameterizer extends AbstractParameterizer {
double gamma = 1.0;
@Override
protected void makeOptions(Parameterization config) {
super.makeOptions(config);
DoubleParameter gammaP = new DoubleParameter(GAMMA_ID);
if(config.grab(gammaP)) {
gamma = gammaP.getValue();
}
}
@Override
protected GammaScaling makeInstance() {
return new GammaScaling(gamma);
}
}
}
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