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package de.lmu.ifi.dbs.elki.index.tree.metrical.mtreevariants.mktrees.mktab;
/*
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 java.util.ArrayList;
import java.util.List;
import de.lmu.ifi.dbs.elki.database.ids.DBID;
import de.lmu.ifi.dbs.elki.database.query.distance.DistanceQuery;
import de.lmu.ifi.dbs.elki.distance.DistanceUtil;
import de.lmu.ifi.dbs.elki.distance.distancevalue.Distance;
import de.lmu.ifi.dbs.elki.index.tree.metrical.mtreevariants.AbstractMTree;
import de.lmu.ifi.dbs.elki.index.tree.metrical.mtreevariants.AbstractMTreeNode;
/**
* Represents a node in a MkMax-Tree.
*
* @author Elke Achtert
*
* @apiviz.has MkTabEntry oneway - - contains
*
* @param <O> object type
* @param <D> distance type
*/
class MkTabTreeNode<O, D extends Distance<D>> extends AbstractMTreeNode<O, D, MkTabTreeNode<O, D>, MkTabEntry<D>> {
private static final long serialVersionUID = 1;
/**
* Empty constructor for Externalizable interface.
*/
public MkTabTreeNode() {
// empty constructor
}
/**
* Creates a MkTabTreeNode object.
*
* @param capacity the capacity (maximum number of entries plus 1 for
* overflow) of this node
* @param isLeaf indicates whether this node is a leaf node
*/
public MkTabTreeNode(int capacity, boolean isLeaf) {
super(capacity, isLeaf, MkTabEntry.class);
}
/**
* Determines and returns the knn distance of this node as the maximum knn
* distance of all entries.
*
* @param distanceFunction the distance function
* @return the knn distance of this node
*/
protected List<D> kNNDistances(DistanceQuery<O, D> distanceFunction) {
int k = getEntry(0).getK_max();
List<D> result = new ArrayList<D>();
for(int i = 0; i < k; i++) {
result.add(distanceFunction.nullDistance());
}
for(int i = 0; i < getNumEntries(); i++) {
for(int j = 0; j < k; j++) {
MkTabEntry<D> entry = getEntry(i);
D kDist = result.remove(j);
result.add(j, DistanceUtil.max(kDist, entry.getKnnDistance(j + 1)));
}
}
return result;
}
@Override
public void adjustEntry(MkTabEntry<D> entry, DBID routingObjectID, D parentDistance, AbstractMTree<O, D, MkTabTreeNode<O, D>, MkTabEntry<D>> mTree) {
super.adjustEntry(entry, routingObjectID, parentDistance, mTree);
// adjust knn distances
entry.setKnnDistances(kNNDistances(mTree.getDistanceQuery()));
}
/**
* Tests, if the parameters of the entry representing this node, are correctly
* set. Subclasses may need to overwrite this method.
*
* @param parent the parent holding the entry representing this node
* @param index the index of the entry in the parents child array
* @param mTree the underlying M-Tree
*/
@Override
protected void integrityCheckParameters(MkTabEntry<D> parentEntry, MkTabTreeNode<O, D> parent, int index, AbstractMTree<O, D, MkTabTreeNode<O, D>, MkTabEntry<D>> mTree) {
super.integrityCheckParameters(parentEntry, parent, index, mTree);
// test knn distances
MkTabEntry<D> entry = parent.getEntry(index);
List<D> knnDistances = kNNDistances(mTree.getDistanceQuery());
if(!entry.getKnnDistances().equals(knnDistances)) {
String soll = knnDistances.toString();
String ist = entry.getKnnDistances().toString();
throw new RuntimeException("Wrong knnDistances in node " + parent.getPageID() + " at index " + index + " (child " + entry + ")" + "\nsoll: " + soll + ",\n ist: " + ist);
}
}
}
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