1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
|
package de.lmu.ifi.dbs.elki.database.lucene;
/*
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.io.IOException;
import org.apache.lucene.analysis.standard.StandardAnalyzer;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.search.Collector;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.Scorer;
import org.apache.lucene.search.similar.MoreLikeThis;
import org.apache.lucene.util.Version;
import de.lmu.ifi.dbs.elki.database.ids.DBID;
import de.lmu.ifi.dbs.elki.database.ids.DBIDArrayIter;
import de.lmu.ifi.dbs.elki.database.ids.DBIDRange;
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.DoubleDBIDList;
import de.lmu.ifi.dbs.elki.database.ids.ModifiableDoubleDBIDList;
import de.lmu.ifi.dbs.elki.database.query.distance.DistanceQuery;
import de.lmu.ifi.dbs.elki.database.query.range.AbstractDistanceRangeQuery;
import de.lmu.ifi.dbs.elki.utilities.exceptions.AbortException;
/**
* Perform range similarity search using lucene.
*
* @author Erich Schubert
* @since 0.6.0
*/
public class LuceneDistanceRangeQuery extends AbstractDistanceRangeQuery<DBID> {
/**
* Lucene search function.
*/
MoreLikeThis mlt;
/**
* Index searcher.
*/
IndexSearcher is;
/**
* DBID range.
*/
DBIDRange ids;
/**
* Constructor.
*
* @param distanceQuery Distance query
*/
public LuceneDistanceRangeQuery(DistanceQuery<DBID> distanceQuery, IndexReader ir, DBIDRange ids) {
super(distanceQuery);
this.ids = ids;
this.mlt = new MoreLikeThis(ir);
this.is = new IndexSearcher(ir);
mlt.setAnalyzer(new StandardAnalyzer(Version.LUCENE_36));
}
@Override
public void getRangeForObject(DBID obj, double range, ModifiableDoubleDBIDList neighbors) {
try {
Query query = mlt.like(ids.getOffset(obj));
is.search(query, new DocumentsCollector(ids, neighbors, range));
}
catch(IOException e) {
throw new AbortException("I/O error in lucene.", e);
}
}
@Override
public DoubleDBIDList getRangeForDBID(DBIDRef id, double range) {
ModifiableDoubleDBIDList result = DBIDUtil.newDistanceDBIDList();
getRangeForDBID(id, range, result);
return result;
}
@Override
public DoubleDBIDList getRangeForObject(DBID obj, double range) {
return getRangeForDBID(obj, range);
}
/**
* Class to collect Lucene results.
*
* @author Erich Schubert
*/
private class DocumentsCollector extends Collector {
/**
* Iterator to convert docid to DBIDs.
*/
private final DBIDArrayIter iter;
/**
* Offset for docid conversion.
*/
private int docBase = 0;
/**
* Scorer class
*/
private Scorer scorer = null;
/**
* Result collector.
*/
final private ModifiableDoubleDBIDList result;
/**
* Threshold range.
*/
final private double range;
/**
* Constructor.
*
* @param ids IDs
* @param result Result collection
* @param range Radius
*/
public DocumentsCollector(DBIDRange ids, ModifiableDoubleDBIDList result, double range) {
super();
this.iter = ids.iter();
this.result = result;
this.range = range;
}
@Override
public boolean acceptsDocsOutOfOrder() {
return true;
}
@Override
public void collect(int docid) throws IOException {
double score = scorer.score();
double dist = (score > 0.) ? (1. / score) : Double.POSITIVE_INFINITY;
if(dist <= range) {
iter.seek(docBase + docid);
result.add(dist, iter);
}
}
@Override
public void setNextReader(IndexReader reader, int docBase) throws IOException {
this.docBase = docBase;
}
@Override
public void setScorer(Scorer scorer) throws IOException {
this.scorer = scorer;
}
}
}
|
