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package de.lmu.ifi.dbs.elki.index.tree.metrical.mtreevariants.mtree;
/*
This file is part of ELKI:
Environment for Developing KDD-Applications Supported by Index-Structures
Copyright (C) 2015
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.data.spatial.SpatialComparable;
import de.lmu.ifi.dbs.elki.data.type.TypeUtil;
import de.lmu.ifi.dbs.elki.database.ids.DBID;
import de.lmu.ifi.dbs.elki.database.ids.DBIDIter;
import de.lmu.ifi.dbs.elki.database.ids.DBIDRef;
import de.lmu.ifi.dbs.elki.database.ids.DBIDUtil;
import de.lmu.ifi.dbs.elki.database.ids.DBIDs;
import de.lmu.ifi.dbs.elki.database.query.distance.DistanceQuery;
import de.lmu.ifi.dbs.elki.database.query.knn.KNNQuery;
import de.lmu.ifi.dbs.elki.database.query.range.RangeQuery;
import de.lmu.ifi.dbs.elki.database.relation.Relation;
import de.lmu.ifi.dbs.elki.database.relation.RelationUtil;
import de.lmu.ifi.dbs.elki.distance.distancefunction.DistanceFunction;
import de.lmu.ifi.dbs.elki.index.DynamicIndex;
import de.lmu.ifi.dbs.elki.index.KNNIndex;
import de.lmu.ifi.dbs.elki.index.RangeIndex;
import de.lmu.ifi.dbs.elki.index.tree.metrical.mtreevariants.MTreeEntry;
import de.lmu.ifi.dbs.elki.index.tree.metrical.mtreevariants.MTreeLeafEntry;
import de.lmu.ifi.dbs.elki.index.tree.metrical.mtreevariants.MTreeSettings;
import de.lmu.ifi.dbs.elki.index.tree.metrical.mtreevariants.query.MTreeQueryUtil;
import de.lmu.ifi.dbs.elki.persistent.PageFile;
import de.lmu.ifi.dbs.elki.utilities.exceptions.ExceptionMessages;
import de.lmu.ifi.dbs.elki.utilities.exceptions.NotImplementedException;
import de.lmu.ifi.dbs.elki.utilities.io.ByteArrayUtil;
/**
* Class for using an m-tree as database index.
*
* @author Erich Schubert
* @since 0.4.0
*
* @param <O> Object type
*/
public class MTreeIndex<O> extends MTree<O>implements RangeIndex<O>, KNNIndex<O>, DynamicIndex {
/**
* The relation indexed.
*/
private Relation<O> relation;
/**
* The distance query.
*/
protected DistanceQuery<O> distanceQuery;
/**
* Constructor.
*
* @param relation Relation indexed
* @param pagefile Page file
* @param settings Tree settings
*/
public MTreeIndex(Relation<O> relation, PageFile<MTreeNode<O>> pagefile, MTreeSettings<O, MTreeNode<O>, MTreeEntry> settings) {
super(pagefile, settings);
this.relation = relation;
this.distanceQuery = getDistanceFunction().instantiate(relation);
}
@Override
public double distance(DBIDRef id1, DBIDRef id2) {
if(id1 == null || id2 == null) {
return Double.NaN;
}
if(DBIDUtil.equal(id1, id2)) {
return 0.;
}
statistics.countDistanceCalculation();
return distanceQuery.distance(id1, id2);
}
@Override
protected void initializeCapacities(MTreeEntry exampleLeaf) {
int distanceSize = ByteArrayUtil.SIZE_DOUBLE; // exampleLeaf.getParentDistance().externalizableSize();
// FIXME: simulate a proper feature size!
int featuresize = 0;
if(TypeUtil.NUMBER_VECTOR_FIELD.isAssignableFromType(relation.getDataTypeInformation())) {
@SuppressWarnings("unchecked")
Relation<? extends SpatialComparable> vrel = (Relation<? extends SpatialComparable>) relation;
featuresize = 8 * RelationUtil.dimensionality(vrel);
}
if(featuresize <= 0) {
getLogger().warning("Relation does not have a dimensionality -- simulating M-tree as external index!");
featuresize = 0;
}
// overhead = index(4), numEntries(4), id(4), isLeaf(0.125)
double overhead = 12.125;
if(getPageSize() - overhead < 0) {
throw new RuntimeException("Node size of " + getPageSize() + " Bytes is chosen too small!");
}
// dirCapacity = (pageSize - overhead) / (nodeID + objectID + coveringRadius
// + parentDistance) + 1
// dirCapacity = (int) (pageSize - overhead) / (4 + 4 + distanceSize +
// distanceSize) + 1;
// dirCapacity = (pageSize - overhead) / (nodeID + **object feature size** +
// coveringRadius + parentDistance) + 1
dirCapacity = (int) (getPageSize() - overhead) / (4 + featuresize + distanceSize + distanceSize) + 1;
if(dirCapacity <= 2) {
throw new RuntimeException("Node size of " + getPageSize() + " Bytes is chosen too small!");
}
if(dirCapacity < 10) {
getLogger().warning("Page size is choosen too small! Maximum number of entries " + "in a directory node = " + (dirCapacity - 1));
}
// leafCapacity = (pageSize - overhead) / (objectID + parentDistance) + 1
// leafCapacity = (int) (pageSize - overhead) / (4 + distanceSize) + 1;
// leafCapacity = (pageSize - overhead) / (objectID + ** object size ** +
// parentDistance) + 1
leafCapacity = (int) (getPageSize() - overhead) / (4 + featuresize + distanceSize) + 1;
if(leafCapacity <= 1) {
throw new RuntimeException("Node size of " + getPageSize() + " Bytes is chosen too small!");
}
if(leafCapacity < 10) {
getLogger().warning("Page size is choosen too small! Maximum number of entries " + "in a leaf node = " + (leafCapacity - 1));
}
}
/**
* @return a new MTreeLeafEntry representing the specified data object
*/
protected MTreeEntry createNewLeafEntry(DBID id, O object, double parentDistance) {
return new MTreeLeafEntry(id, parentDistance);
}
@Override
public void initialize() {
super.initialize();
insertAll(relation.getDBIDs());
}
@Override
public void insert(DBIDRef id) {
insert(createNewLeafEntry(DBIDUtil.deref(id), relation.get(id), Double.NaN), false);
}
@Override
public void insertAll(DBIDs ids) {
List<MTreeEntry> objs = new ArrayList<>(ids.size());
for(DBIDIter iter = ids.iter(); iter.valid(); iter.advance()) {
DBID id = DBIDUtil.deref(iter);
final O object = relation.get(id);
objs.add(createNewLeafEntry(id, object, Double.NaN));
}
insertAll(objs);
}
/**
* Throws an UnsupportedOperationException since deletion of objects is not
* yet supported by an M-Tree.
*
* @throws UnsupportedOperationException thrown, since deletions aren't
* implemented yet.
*/
@Override
public final boolean delete(DBIDRef id) {
throw new NotImplementedException(ExceptionMessages.UNSUPPORTED_NOT_YET);
}
/**
* Throws an UnsupportedOperationException since deletion of objects is not
* yet supported by an M-Tree.
*
* @throws UnsupportedOperationException thrown, since deletions aren't
* implemented yet.
*/
@Override
public void deleteAll(DBIDs ids) {
throw new NotImplementedException(ExceptionMessages.UNSUPPORTED_NOT_YET);
}
@Override
public KNNQuery<O> getKNNQuery(DistanceQuery<O> distanceQuery, Object... hints) {
// Query on the relation we index
if(distanceQuery.getRelation() != relation) {
return null;
}
DistanceFunction<? super O> distanceFunction = (DistanceFunction<? super O>) distanceQuery.getDistanceFunction();
if(!this.getDistanceFunction().equals(distanceFunction)) {
getLogger().debug("Distance function not supported by index - or 'equals' not implemented right!");
return null;
}
DistanceQuery<O> dq = distanceFunction.instantiate(relation);
return MTreeQueryUtil.getKNNQuery(this, dq, hints);
}
@Override
public RangeQuery<O> getRangeQuery(DistanceQuery<O> distanceQuery, Object... hints) {
// Query on the relation we index
if(distanceQuery.getRelation() != relation) {
return null;
}
DistanceFunction<? super O> distanceFunction = (DistanceFunction<? super O>) distanceQuery.getDistanceFunction();
if(!this.getDistanceFunction().equals(distanceFunction)) {
getLogger().debug("Distance function not supported by index - or 'equals' not implemented right!");
return null;
}
DistanceQuery<O> dq = distanceFunction.instantiate(relation);
return MTreeQueryUtil.getRangeQuery(this, dq);
}
@Override
public String getLongName() {
return "M-Tree";
}
@Override
public String getShortName() {
return "mtree";
}
}
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