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.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 Minimum distance for a pair of
* FeatureVectors.
*
* @author Erich Schubert
*/
// TODO: add spatial?
public class MinimumDistanceFunction extends AbstractVectorDoubleDistanceFunction implements SpatialPrimitiveDoubleDistanceFunction<NumberVector<?, ?>> {
/**
* Static instance. Use this.
*/
public static final MinimumDistanceFunction STATIC = new MinimumDistanceFunction();
/**
* Provides a Minimum distance function that can compute the Minimum distance
* (that is a DoubleDistance) for FeatureVectors.
*
* @deprecated Use static instance!
*/
@Deprecated
public MinimumDistanceFunction() {
super();
}
@Override
public double doubleDistance(NumberVector<?, ?> v1, NumberVector<?, ?> v2) {
final int dim = v1.getDimensionality();
if(dim != v2.getDimensionality()) {
throw new IllegalArgumentException("Different dimensionality of FeatureVectors" + "\n first argument: " + v1.toString() + "\n second argument: " + v2.toString());
}
double min = Double.MAX_VALUE;
for(int i = 1; i <= dim; i++) {
final double d = Math.abs(v1.doubleValue(i) - v2.doubleValue(i));
min = Math.min(d, min);
}
return min;
}
@Override
public double doubleMinDist(SpatialComparable mbr1, SpatialComparable mbr2) {
final int dim = mbr1.getDimensionality();
if(dim != mbr2.getDimensionality()) {
throw new IllegalArgumentException("Different dimensionality of FeatureVectors" + "\n first argument: " + mbr1.toString() + "\n second argument: " + mbr2.toString());
}
double min = Double.MAX_VALUE;
for(int i = 1; i <= dim; i++) {
final double min1 = mbr1.getMin(i);
final double max1 = mbr1.getMax(i);
final double min2 = mbr2.getMin(i);
final double max2 = mbr2.getMax(i);
final double d;
if(max1 <= min2) {
d = min2 - max1;
}
else if(max2 <= min1) {
d = min1 - max2;
}
else {
// Overlap in this dimension
min = 0.0;
break;
}
min = Math.min(d, min);
}
return min;
}
@Override
public double doubleCenterDistance(SpatialComparable mbr1, SpatialComparable mbr2) {
final int dim = mbr1.getDimensionality();
if(dim != mbr2.getDimensionality()) {
throw new IllegalArgumentException("Different dimensionality of FeatureVectors" + "\n first argument: " + mbr1.toString() + "\n second argument: " + mbr2.toString());
}
double min = Double.MAX_VALUE;
for(int i = 1; i <= dim; i++) {
final double d = Math.abs((mbr1.getMin(i) + mbr1.getMax(i)) / 2 - (mbr2.getMin(i) + mbr1.getMax(i)) / 2);
min = Math.min(d, min);
}
return min;
}
@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 String toString() {
return "MinimumDistance";
}
@Override
public <T extends NumberVector<?, ?>> SpatialPrimitiveDistanceQuery<T, DoubleDistance> instantiate(Relation<T> relation) {
return new SpatialPrimitiveDistanceQuery<T, DoubleDistance>(relation, this);
}
@Override
public boolean equals(Object obj) {
if(obj == null) {
return false;
}
if(obj == this) {
return true;
}
return this.getClass().equals(obj.getClass());
}
/**
* Parameterization class.
*
* @author Erich Schubert
*
* @apiviz.exclude
*/
public static class Parameterizer extends AbstractParameterizer {
@Override
protected MinimumDistanceFunction makeInstance() {
return MinimumDistanceFunction.STATIC;
}
}
}