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package de.lmu.ifi.dbs.elki.index.tree.metrical.mtreevariants.mktrees.mkapp;
/*
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.Arrays;
import java.util.logging.Logger;
import de.lmu.ifi.dbs.elki.database.ids.DBID;
import de.lmu.ifi.dbs.elki.distance.distancevalue.NumberDistance;
import de.lmu.ifi.dbs.elki.index.tree.metrical.mtreevariants.AbstractMTree;
import de.lmu.ifi.dbs.elki.index.tree.metrical.mtreevariants.AbstractMTreeNode;
import de.lmu.ifi.dbs.elki.logging.LoggingConfiguration;
import de.lmu.ifi.dbs.elki.utilities.FormatUtil;
/**
* Represents a node in an MkApp-Tree.
*
* @author Elke Achtert
*
* @apiviz.has MkAppEntry oneway - - contains
*
* @param <O> object type
* @param <D> distance type
*/
class MkAppTreeNode<O, D extends NumberDistance<D, ?>> extends AbstractMTreeNode<O, D, MkAppTreeNode<O, D>, MkAppEntry<D>> {
private static final long serialVersionUID = 1;
/**
* Empty constructor for Externalizable interface.
*/
public MkAppTreeNode() {
// empty constructor
}
/**
* Creates a MkAppTreeNode 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 MkAppTreeNode(int capacity, boolean isLeaf) {
super(capacity, isLeaf, MkAppEntry.class);
}
/**
* Determines and returns the polynomial approximation for the knn distances
* of this node as the maximum of the polynomial approximations of all
* entries.
*
* @return the conservative approximation for the knn distances
*/
protected PolynomialApproximation knnDistanceApproximation() {
int p_max = 0;
double[] b = null;
for(int i = 0; i < getNumEntries(); i++) {
MkAppEntry<D> entry = getEntry(i);
PolynomialApproximation approximation = entry.getKnnDistanceApproximation();
if(b == null) {
p_max = approximation.getPolynomialOrder();
b = new double[p_max];
}
for(int p = 0; p < p_max; p++) {
b[p] += approximation.getB(p);
}
}
for(int p = 0; p < p_max; p++) {
b[p] /= p_max;
}
if(LoggingConfiguration.DEBUG) {
StringBuffer msg = new StringBuffer();
msg.append("b " + FormatUtil.format(b, 4));
Logger.getLogger(this.getClass().getName()).fine(msg.toString());
}
return new PolynomialApproximation(b);
}
/**
* Adjusts the parameters of the entry representing this node.
*
* @param entry the entry representing this node
* @param routingObjectID the id of the (new) routing object of this node
* @param parentDistance the distance from the routing object of this node to
* the routing object of the parent node
* @param mTree the M-Tree object holding this node
*/
@Override
public void adjustEntry(MkAppEntry<D> entry, DBID routingObjectID, D parentDistance, AbstractMTree<O, D, MkAppTreeNode<O, D>, MkAppEntry<D>> mTree) {
super.adjustEntry(entry, routingObjectID, parentDistance, mTree);
// entry.setKnnDistanceApproximation(knnDistanceApproximation());
}
@Override
protected void integrityCheckParameters(MkAppEntry<D> parentEntry, MkAppTreeNode<O, D> parent, int index, AbstractMTree<O, D, MkAppTreeNode<O, D>, MkAppEntry<D>> mTree) {
super.integrityCheckParameters(parentEntry, parent, index, mTree);
MkAppEntry<D> entry = parent.getEntry(index);
PolynomialApproximation approximation_soll = knnDistanceApproximation();
PolynomialApproximation approximation_ist = entry.getKnnDistanceApproximation();
if(!Arrays.equals(approximation_ist.getCoefficients(), approximation_soll.getCoefficients())) {
String soll = approximation_soll.toString();
String ist = entry.getKnnDistanceApproximation().toString();
throw new RuntimeException("Wrong polynomial approximation in node " + parent.getPageID() + " at index " + index + " (child " + entry + ")" + "\nsoll: " + soll + ",\n ist: " + ist);
}
}
}
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