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package de.lmu.ifi.dbs.elki.index.tree.metrical.mtreevariants;
/*
This file is part of ELKI:
Environment for Developing KDD-Applications Supported by Index-Structures
Copyright (C) 2014
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.logging.Logger;
import de.lmu.ifi.dbs.elki.database.ids.DBID;
import de.lmu.ifi.dbs.elki.index.tree.AbstractNode;
import de.lmu.ifi.dbs.elki.logging.LoggingConfiguration;
/**
* Abstract super class for nodes in M-Tree variants.
*
* @author Elke Achtert
*
* @apiviz.has MTreeEntry oneway - - contains
* @apiviz.excludeSubtypes
*
* @param <O> the type of DatabaseObject to be stored in the M-Tree
* @param <N> the type of AbstractMTreeNode used in the M-Tree
* @param <E> the type of MetricalEntry used in the M-Tree
*/
public abstract class AbstractMTreeNode<O, N extends AbstractMTreeNode<O, N, E>, E extends MTreeEntry> extends AbstractNode<E> {
/**
* Empty constructor for Externalizable interface.
*/
public AbstractMTreeNode() {
// empty constructor
}
/**
* Creates a new MTreeNode with the specified parameters.
*
* @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
* @param eclass Entry class, to initialize array storage
*/
public AbstractMTreeNode(int capacity, boolean isLeaf, Class<? super E> eclass) {
super(capacity, isLeaf, eclass);
}
/**
* Adjusts the parameters of the entry representing this node (e.g. after
* insertion of new objects). Subclasses may need to overwrite this method.
*
* @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
*/
public void adjustEntry(E entry, DBID routingObjectID, double parentDistance, AbstractMTree<O, N, E, ?> mTree) {
entry.setRoutingObjectID(routingObjectID);
entry.setParentDistance(parentDistance);
entry.setCoveringRadius(coveringRadius(entry.getRoutingObjectID(), mTree));
for (int i = 0; i < getNumEntries(); i++) {
E childEntry = getEntry(i);
double dist = mTree.distance(routingObjectID, childEntry.getRoutingObjectID());
childEntry.setParentDistance(dist);
}
}
/**
* Determines and returns the covering radius of this node.
*
* @param routingObjectID the object id of the routing object of this node
* @param mTree the M-Tree
* @return the covering radius of this node
*/
public double coveringRadius(DBID routingObjectID, AbstractMTree<O, N, E, ?> mTree) {
double coveringRadius = 0.;
for (int i = 0; i < getNumEntries(); i++) {
E entry = getEntry(i);
double distance = mTree.distance(entry.getRoutingObjectID(), routingObjectID) + entry.getCoveringRadius();
coveringRadius = Math.max(coveringRadius, distance);
}
return coveringRadius;
}
/**
* Tests this node (for debugging purposes).
*
* @param mTree the M-Tree holding this node
* @param entry the entry representing this node
*/
@SuppressWarnings("unchecked")
public final void integrityCheck(AbstractMTree<O, N, E, ?> mTree, E entry) {
// leaf node
if (isLeaf()) {
for (int i = 0; i < getCapacity(); i++) {
E e = getEntry(i);
if (i < getNumEntries() && e == null) {
throw new RuntimeException("i < numEntries && entry == null");
}
if (i >= getNumEntries() && e != null) {
throw new RuntimeException("i >= numEntries && entry != null");
}
}
}
// dir node
else {
N tmp = mTree.getNode(getEntry(0));
boolean childIsLeaf = tmp.isLeaf();
for (int i = 0; i < getCapacity(); i++) {
E e = getEntry(i);
if (i < getNumEntries() && e == null) {
throw new RuntimeException("i < numEntries && entry == null");
}
if (i >= getNumEntries() && e != null) {
throw new RuntimeException("i >= numEntries && entry != null");
}
if (e != null) {
N node = mTree.getNode(e);
if (childIsLeaf && !node.isLeaf()) {
for (int k = 0; k < getNumEntries(); k++) {
mTree.getNode(getEntry(k));
}
throw new RuntimeException("Wrong Child in " + this + " at " + i);
}
if (!childIsLeaf && node.isLeaf()) {
throw new RuntimeException("Wrong Child: child id no leaf, but node is leaf!");
}
// noinspection unchecked
node.integrityCheckParameters(entry, (N) this, i, mTree);
node.integrityCheck(mTree, e);
}
}
if (LoggingConfiguration.DEBUG) {
Logger.getLogger(this.getClass().getName()).fine("DirNode " + getPageID() + " ok!");
}
}
}
/**
* Tests, if the parameters of the entry representing this node, are correctly
* set. Subclasses may need to overwrite this method.
*
* @param parentEntry the entry representing the parent
* @param parent the parent holding the entry representing this node
* @param index the index of the entry in the parents child arry
* @param mTree the M-Tree holding this node
*/
protected void integrityCheckParameters(E parentEntry, N parent, int index, AbstractMTree<O, N, E, ?> mTree) {
// test if parent distance is correctly set
E entry = parent.getEntry(index);
double parentDistance = mTree.distance(entry.getRoutingObjectID(), parentEntry.getRoutingObjectID());
if (Math.abs(entry.getParentDistance() - parentDistance) > 1E-10) {
throw new RuntimeException("Wrong parent distance in node " + parent.getPageID() + " at index " + index + " (child " + entry + ")" + "\nsoll: " + parentDistance + ",\n ist: " + entry.getParentDistance());
}
// test if covering radius is correctly set
double mincover = parentDistance + entry.getCoveringRadius();
if (parentEntry.getCoveringRadius() < mincover) {
if (Math.abs(parentDistance - entry.getCoveringRadius()) > 1e-10) {
String msg = "pcr < pd + cr \n" + parentEntry.getCoveringRadius() + " < " + parentDistance + " + " + entry.getCoveringRadius() + "in node " + parent.getPageID() + " at index " + index + " (child " + entry + "):\n" + "dist(" + entry.getRoutingObjectID() + " - " + parentEntry.getRoutingObjectID() + ")" + " > cr(" + entry + ")";
throw new RuntimeException(msg);
}
}
}
}
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