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package de.lmu.ifi.dbs.elki.distance.distancefunction;
/*
This file is part of ELKI:
Environment for Developing KDD-Applications Supported by Index-Structures
Copyright (C) 2011
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.data.NumberVector;
import de.lmu.ifi.dbs.elki.data.spatial.SpatialComparable;
import de.lmu.ifi.dbs.elki.database.query.distance.SpatialDistanceQuery;
import de.lmu.ifi.dbs.elki.database.query.distance.SpatialPrimitiveDistanceQuery;
import de.lmu.ifi.dbs.elki.database.relation.Relation;
import de.lmu.ifi.dbs.elki.distance.distancevalue.DoubleDistance;
import de.lmu.ifi.dbs.elki.utilities.optionhandling.AbstractParameterizer;
/**
* Maximum distance function to compute the Maximum distance for a pair of
* FeatureVectors.
*
* @author Erich Schubert
*/
public class MaximumDistanceFunction extends LPNormDistanceFunction implements SpatialPrimitiveDoubleDistanceFunction<NumberVector<?, ?>> {
/**
* Static instance.
*/
public static final MaximumDistanceFunction STATIC = new MaximumDistanceFunction();
/**
* Provides a Maximum distance function that can compute the Manhattan
* distance (that is a DoubleDistance) for FeatureVectors.
*
* @deprecated Use static instance!
*/
@Deprecated
public MaximumDistanceFunction() {
super(Double.POSITIVE_INFINITY);
}
@Override
public double doubleDistance(NumberVector<?, ?> v1, NumberVector<?, ?> v2) {
final int dim1 = v1.getDimensionality();
if(dim1 != v2.getDimensionality()) {
throw new IllegalArgumentException("Different dimensionality of FeatureVectors" + "\n first argument: " + v1.toString() + "\n second argument: " + v2.toString());
}
double max = 0;
for(int i = 1; i <= dim1; i++) {
final double d = Math.abs(v1.doubleValue(i) - v2.doubleValue(i));
max = Math.max(d, max);
}
return max;
}
@Override
public double doubleMinDist(SpatialComparable mbr1, SpatialComparable mbr2) {
final int dim1 = mbr1.getDimensionality();
if(dim1 != mbr2.getDimensionality()) {
throw new IllegalArgumentException("Different dimensionality of objects.");
}
double max = 0;
for(int i = 1; i <= dim1; i++) {
final double d;
if(mbr1.getMax(i) < mbr2.getMin(i)) {
d = mbr2.getMin(i) - mbr1.getMin(i);
}
else if(mbr1.getMin(i) > mbr2.getMax(i)) {
d = mbr1.getMin(i) - mbr2.getMax(i);
}
else {
// The object overlap in this dimension.
continue;
}
max = Math.max(d, max);
}
return max;
}
@Override
public double doubleCenterDistance(SpatialComparable mbr1, SpatialComparable mbr2) {
final int dim1 = mbr1.getDimensionality();
if(dim1 != mbr2.getDimensionality()) {
throw new IllegalArgumentException("Different dimensionality of objects.");
}
double max = 0;
for(int i = 1; i <= dim1; i++) {
final double c1 = (mbr1.getMax(i) - mbr1.getMin(i)) / 2;
final double c2 = (mbr2.getMax(i) - mbr2.getMin(i)) / 2;
final double d = Math.abs(c2 - c1);
max = Math.max(d, max);
}
return max;
}
@Override
public DoubleDistance minDist(SpatialComparable mbr1, SpatialComparable mbr2) {
return new DoubleDistance(doubleMinDist(mbr1, mbr2));
}
@Override
public DoubleDistance centerDistance(SpatialComparable mbr1, SpatialComparable mbr2) {
return new DoubleDistance(doubleCenterDistance(mbr1, mbr2));
}
@Override
public boolean isMetric() {
return true;
}
@Override
public <T extends NumberVector<?, ?>> SpatialDistanceQuery<T, DoubleDistance> instantiate(Relation<T> relation) {
return new SpatialPrimitiveDistanceQuery<T, DoubleDistance>(relation, this);
}
@Override
public String toString() {
return "MaximumDistance";
}
@Override
public boolean equals(Object obj) {
if(obj == null) {
return false;
}
if(obj == this) {
return true;
}
if (this.getClass().equals(obj.getClass())) {
return true;
}
return super.equals(obj);
}
/**
* Parameterization class.
*
* @author Erich Schubert
*
* @apiviz.exclude
*/
public static class Parameterizer extends AbstractParameterizer {
@Override
protected MaximumDistanceFunction makeInstance() {
return MaximumDistanceFunction.STATIC;
}
}
}
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