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package de.lmu.ifi.dbs.elki.utilities.scaling.outlier;
/*
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.database.ids.DBIDIter;
import de.lmu.ifi.dbs.elki.database.relation.DoubleRelation;
import de.lmu.ifi.dbs.elki.math.DoubleMinMax;
import de.lmu.ifi.dbs.elki.result.outlier.OutlierResult;
import de.lmu.ifi.dbs.elki.utilities.datastructures.arraylike.NumberArrayAdapter;
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;
/**
* Scaling that can map arbitrary positive values to a value in the range of
* [0:1].
*
* Transformation is done by taking the square root, then doing a linear linear
* mapping onto 0:1 using the minimum values seen.
*
* @author Erich Schubert
* @since 0.3
*/
public class OutlierSqrtScaling implements OutlierScalingFunction {
/**
* Minimum and maximum values.
*/
protected double min, max;
/**
* Predefined minimum and maximum values.
*/
protected Double pmin = null, pmax = null;
/**
* Scaling factor
*/
protected double factor;
/**
* Constructor.
*
* @param pmin Predefined minimum
* @param pmax Predefined maximum
*/
public OutlierSqrtScaling(Double pmin, Double pmax) {
super();
this.pmin = pmin;
this.pmax = pmax;
}
@Override
public double getScaled(double value) {
assert (factor != 0) : "prepare() was not run prior to using the scaling function.";
if (value <= min) {
return 0;
}
return Math.min(1, (Math.sqrt(value - min) / factor));
}
@Override
public void prepare(OutlierResult or) {
if (pmin == null || pmax == null) {
DoubleMinMax mm = new DoubleMinMax();
DoubleRelation scores = or.getScores();
for (DBIDIter id = scores.iterDBIDs(); id.valid(); id.advance()) {
double val = scores.doubleValue(id);
if (!Double.isInfinite(val)) {
mm.put(val);
}
}
min = (pmin == null) ? mm.getMin() : pmin;
max = (pmax == null) ? mm.getMax() : pmax;
}
factor = Math.sqrt(max - min);
}
@Override
public <A> void prepare(A array, NumberArrayAdapter<?, A> adapter) {
if (pmin == null || pmax == null) {
DoubleMinMax mm = new DoubleMinMax();
final int size = adapter.size(array);
for (int i = 0; i < size; i++) {
double val = adapter.getDouble(array, i);
if (!Double.isInfinite(val)) {
mm.put(val);
}
}
min = (pmin == null) ? mm.getMin() : pmin;
max = (pmax == null) ? mm.getMax() : pmax;
}
factor = Math.sqrt(max - min);
}
@Override
public double getMin() {
return 0.0;
}
@Override
public double getMax() {
return 1.0;
}
/**
* Parameterization class.
*
* @author Erich Schubert
*
* @apiviz.exclude
*/
public static class Parameterizer extends AbstractParameterizer {
/**
* Parameter to specify the fixed minimum to use.
* <p>
* Key: {@code -sqrtscale.min}
* </p>
*/
public static final OptionID MIN_ID = new OptionID("sqrtscale.min", "Fixed minimum to use in sqrt scaling.");
/**
* Parameter to specify the fixed maximum to use.
* <p>
* Key: {@code -sqrtscale.max}
* </p>
*/
public static final OptionID MAX_ID = new OptionID("sqrtscale.max", "Fixed maximum to use in sqrt scaling.");
/**
* Predefined minimum value.
*/
protected double min;
/**
* Predefined maximum value.
*/
protected double max;
@Override
protected void makeOptions(Parameterization config) {
super.makeOptions(config);
DoubleParameter minP = new DoubleParameter(MIN_ID);
minP.setOptional(true);
if (config.grab(minP)) {
min = minP.getValue();
}
DoubleParameter maxP = new DoubleParameter(MAX_ID);
maxP.setOptional(true);
if (config.grab(maxP)) {
max = maxP.getValue();
}
}
@Override
protected OutlierSqrtScaling makeInstance() {
return new OutlierSqrtScaling(min, max);
}
}
}
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