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package de.lmu.ifi.dbs.elki.index.tree.spatial.rstarvariants.strategies.reinsert;
import java.util.Arrays;
import java.util.Collections;
import de.lmu.ifi.dbs.elki.data.DoubleVector;
import de.lmu.ifi.dbs.elki.data.spatial.SpatialComparable;
import de.lmu.ifi.dbs.elki.data.spatial.SpatialUtil;
import de.lmu.ifi.dbs.elki.distance.distancefunction.SpatialPrimitiveDoubleDistanceFunction;
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.pairs.DoubleIntPair;
/*
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/>.
*/
/**
* Reinsert objects on page overflow, starting with farther objects first (even
* when they will likely be inserted into the same page again!)
*
* Alternative strategy mentioned in the R*-tree
*
* @author Erich Schubert
*/
@Reference(authors = "N. Beckmann, H.-P. Kriegel, R. Schneider, B. Seeger", title = "The R*-tree: an efficient and robust access method for points and rectangles", booktitle = "Proceedings of the 1990 ACM SIGMOD International Conference on Management of Data, Atlantic City, NJ, May 23-25, 1990", url = "http://dx.doi.org/10.1145/93597.98741")
public class FarReinsert extends AbstractPartialReinsert {
/**
* Constructor.
*
* @param reinsertAmount Amount to reinsert
* @param distanceFunction Distance function
*/
public FarReinsert(double reinsertAmount, SpatialPrimitiveDoubleDistanceFunction<?> distanceFunction) {
super(reinsertAmount, distanceFunction);
}
@Override
public <A> int[] computeReinserts(A entries, ArrayAdapter<? extends SpatialComparable, ? super A> getter, SpatialComparable page) {
DoubleIntPair[] order = new DoubleIntPair[getter.size(entries)];
DoubleVector centroid = new DoubleVector(SpatialUtil.centroid(page));
for(int i = 0; i < order.length; i++) {
double distance = distanceFunction.doubleMinDist(new DoubleVector(SpatialUtil.centroid(getter.get(entries, i))), centroid);
order[i] = new DoubleIntPair(distance, i);
}
Arrays.sort(order, Collections.reverseOrder());
int num = (int) (reinsertAmount * order.length);
int[] re = new int[num];
for(int i = 0; i < num; i++) {
re[i] = order[i].second;
}
return re;
}
/**
* Parameterization class.
*
* @author Erich Schubert
*
* @apiviz.exclude
*/
public static class Parameterizer extends AbstractPartialReinsert.Parameterizer {
@Override
protected Object makeInstance() {
return new CloseReinsert(reinsertAmount, distanceFunction);
}
}
}
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