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Diffstat (limited to 'src/tutorial/distancefunction/MultiLPNorm.java')
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diff --git a/src/tutorial/distancefunction/MultiLPNorm.java b/src/tutorial/distancefunction/MultiLPNorm.java new file mode 100644 index 00000000..6909d2ff --- /dev/null +++ b/src/tutorial/distancefunction/MultiLPNorm.java @@ -0,0 +1,126 @@ +package tutorial.distancefunction; + +import de.lmu.ifi.dbs.elki.data.NumberVector; +import de.lmu.ifi.dbs.elki.data.type.SimpleTypeInformation; +import de.lmu.ifi.dbs.elki.data.type.VectorFieldTypeInformation; +import de.lmu.ifi.dbs.elki.distance.distancefunction.AbstractVectorDoubleDistanceFunction; +import de.lmu.ifi.dbs.elki.utilities.datastructures.arraylike.ArrayLikeUtil; +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.DoubleListParameter; + +/* + This file is part of ELKI: + Environment for Developing KDD-Applications Supported by Index-Structures + + Copyright (C) 2012 + 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/>. + */ + +/** + * Tutorial example for ELKI. + * + * See <a + * href="http://elki.dbs.ifi.lmu.de/wiki/Tutorial/DistanceFunctions">Distance + * function tutorial</a> + * + * @author Erich Schubert + */ +public class MultiLPNorm extends AbstractVectorDoubleDistanceFunction { + /** + * The exponents + */ + double[] ps; + + /** + * Normalization factor (count(ps)/sum(ps)) + */ + double pinv; + + /** + * Constructor. + * + * @param ps The exponents + */ + public MultiLPNorm(double[] ps) { + super(); + double sum = 0.0; + for(int dim = 0; dim < ps.length; dim++) { + assert (ps[dim] >= 0) : "Negative exponents are not allowed."; + sum += ps[dim]; + } + assert (sum > 0) : "At least one exponent should be different from 0!"; + + this.ps = ps; + this.pinv = ps.length / sum; + } + + @Override + public double doubleDistance(NumberVector<?, ?> o1, NumberVector<?, ?> o2) { + assert o1.getDimensionality() == ps.length : "Inappropriate dimensionality!"; + assert o2.getDimensionality() == ps.length : "Inappropriate dimensionality!"; + + double sum = 0.0; + for(int dim = 0; dim < ps.length; dim++) { + if(ps[dim] > 0) { + final double delta = Math.abs(o1.doubleValue(dim + 1) - o2.doubleValue(dim + 1)); + sum += Math.pow(delta, ps[dim]); + } + } + return Math.pow(sum, pinv); + } + + @Override + public SimpleTypeInformation<? super NumberVector<?, ?>> getInputTypeRestriction() { + return new VectorFieldTypeInformation<NumberVector<?, ?>>(NumberVector.class, ps.length); + } + + /** + * Parameterization class example + * + * @author Erich Schubert + */ + public static class Parameterizer extends AbstractParameterizer { + /** + * Option ID for the exponents <code> + * -multinorm.ps + * </code> + */ + public static final OptionID EXPONENTS_ID = OptionID.getOrCreateOptionID("multinorm.ps", "The exponents to use for this distance function"); + + /** + * P exponents + */ + double[] ps; + + @Override + protected void makeOptions(Parameterization config) { + super.makeOptions(config); + DoubleListParameter ps_param = new DoubleListParameter(EXPONENTS_ID); + if(config.grab(ps_param)) { + ps = ArrayLikeUtil.toPrimitiveDoubleArray(ps_param.getValue()); + } + } + + @Override + protected MultiLPNorm makeInstance() { + return new MultiLPNorm(ps); + } + } +}
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