package de.lmu.ifi.dbs.elki.index.tree.spatial.rstarvariants.strategies.insert;
/*
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/>.
*/
import de.lmu.ifi.dbs.elki.data.spatial.SpatialComparable;
import de.lmu.ifi.dbs.elki.data.spatial.SpatialUtil;
import de.lmu.ifi.dbs.elki.utilities.datastructures.arraylike.ArrayAdapter;
import de.lmu.ifi.dbs.elki.utilities.documentation.Reference;
import de.lmu.ifi.dbs.elki.utilities.optionhandling.AbstractParameterizer;
/**
* The default R-Tree insertion strategy: find rectangle with least volume
* enlargement.
*
* <p>
* Antonin Guttman:<br/>
* R-Trees: A Dynamic Index Structure For Spatial Searching<br />
* in Proceedings of the 1984 ACM SIGMOD international conference on Management
* of data.
* </p>
*
* @author Erich Schubert
*/
@Reference(authors = "Antonin Guttman", title = "R-Trees: A Dynamic Index Structure For Spatial Searching", booktitle = "Proceedings of the 1984 ACM SIGMOD international conference on Management of data", url = "http://dx.doi.org/10.1145/971697.602266")
public class LeastEnlargementInsertionStrategy implements InsertionStrategy {
/**
* Static instance.
*/
public static final LeastEnlargementInsertionStrategy STATIC = new LeastEnlargementInsertionStrategy();
/**
* Constructor.
*/
public LeastEnlargementInsertionStrategy() {
super();
}
@Override
public <A> int choose(A options, ArrayAdapter<? extends SpatialComparable, A> getter, SpatialComparable obj, int height, int depth) {
final int size = getter.size(options);
assert (size > 0) : "Choose from empty set?";
double leastEnlargement = Double.POSITIVE_INFINITY;
int best = -1;
for(int i = 0; i < size; i++) {
SpatialComparable entry = getter.get(options, i);
double enlargement = SpatialUtil.enlargement(entry, obj);
if(enlargement < leastEnlargement) {
leastEnlargement = enlargement;
best = i;
}
}
assert (best > -1);
return best;
}
/**
* Parameterization class.
*
* @author Erich Schubert
*
* @apiviz.exclude
*/
public static class Parameterizer extends AbstractParameterizer {
@Override
protected LeastEnlargementInsertionStrategy makeInstance() {
return LeastEnlargementInsertionStrategy.STATIC;
}
}
}