summaryrefslogtreecommitdiff
path: root/src/de/lmu/ifi/dbs/elki/distance/distancefunction/external/FileBasedDoubleDistanceFunction.java
blob: 055d5d7519aabb971a485fc63def0f4892e78b79 (plain)
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
176
177
178
179
180
181
package de.lmu.ifi.dbs.elki.distance.distancefunction.external;

/*
 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 gnu.trove.map.TLongDoubleMap;
import gnu.trove.map.hash.TLongDoubleHashMap;

import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;

import de.lmu.ifi.dbs.elki.distance.distancefunction.AbstractDBIDRangeDistanceFunction;
import de.lmu.ifi.dbs.elki.utilities.FileUtil;
import de.lmu.ifi.dbs.elki.utilities.documentation.Description;
import de.lmu.ifi.dbs.elki.utilities.documentation.Title;
import de.lmu.ifi.dbs.elki.utilities.exceptions.AbortException;
import de.lmu.ifi.dbs.elki.utilities.optionhandling.AbstractParameterizer;
import de.lmu.ifi.dbs.elki.utilities.optionhandling.OptionID;
import de.lmu.ifi.dbs.elki.utilities.optionhandling.parameterization.Parameterization;
import de.lmu.ifi.dbs.elki.utilities.optionhandling.parameters.FileParameter;
import de.lmu.ifi.dbs.elki.utilities.optionhandling.parameters.ObjectParameter;

/**
 * Distance function that is based on double distances given by a distance
 * matrix of an external ascii file.
 * 
 * See {@link AsciiDistanceParser} for the default input format.
 * 
 * TODO: use a {@code double[]} instead of the hash map.
 * 
 * @author Elke Achtert
 * @author Erich Schubert
 */
@Title("File based double distance for database objects.")
@Description("Loads double distance values from an external text file.")
public class FileBasedDoubleDistanceFunction extends AbstractDBIDRangeDistanceFunction {
  /**
   * The distance cache
   */
  private TLongDoubleMap cache;

  /**
   * Constructor.
   * 
   * @param parser Parser
   * @param matrixfile input file
   */
  public FileBasedDoubleDistanceFunction(DistanceParser parser, File matrixfile) {
    super();
    try {
      loadCache(parser, matrixfile);
    }
    catch(IOException e) {
      throw new AbortException("Could not load external distance file: " + matrixfile.toString(), e);
    }
  }

  @Override
  public double distance(int i1, int i2) {
    if(i1 == i2) {
      return 0.;
    }
    return cache.get(makeKey(i1, i2));
  }

  private void loadCache(DistanceParser parser, File matrixfile) throws IOException {
    InputStream in = new BufferedInputStream(FileUtil.tryGzipInput(new FileInputStream(matrixfile)));
    cache = new TLongDoubleHashMap();
    parser.parse(in, new DistanceCacheWriter() {
      @Override
      public void put(int id1, int id2, double distance) {
        cache.put(makeKey(id1, id2), distance);
      }

      @Override
      public boolean containsKey(int id1, int id2) {
        return cache.containsKey(makeKey(id1, id2));
      }
    });
  }

  /**
   * Combine two integer ids into a long value.
   * 
   * @param i1 First id
   * @param i2 Second id
   * @return Combined value
   */
  protected static final long makeKey(int i1, int i2) {
    return (i1 < i2) //
    ? ((((long) i1) << 32) | i2)//
    : ((((long) i2) << 32) | i1);
  }

  @Override
  public boolean equals(Object obj) {
    if(obj == null) {
      return false;
    }
    if(getClass() != obj.getClass()) {
      return false;
    }
    FileBasedDoubleDistanceFunction other = (FileBasedDoubleDistanceFunction) obj;
    return this.cache.equals(other.cache);
  }

  /**
   * Parameterization class.
   * 
   * @author Erich Schubert
   * 
   * @apiviz.exclude
   */
  public static class Parameterizer extends AbstractParameterizer {
    /**
     * Parameter that specifies the name of the distance matrix file.
     * <p>
     * Key: {@code -distance.matrix}
     * </p>
     */
    public static final OptionID MATRIX_ID = new OptionID("distance.matrix", //
    "The name of the file containing the distance matrix.");

    /**
     * Optional parameter to specify the parsers to provide a database, must
     * extend {@link DistanceParser}. If this parameter is not set,
     * {@link AsciiDistanceParser} is used as parser for all input files.
     * <p>
     * Key: {@code -distance.parser}
     * </p>
     */
    public static final OptionID PARSER_ID = new OptionID("distance.parser", //
    "Parser used to load the distance matrix.");

    protected File matrixfile = null;

    protected DistanceParser parser = null;

    @Override
    protected void makeOptions(Parameterization config) {
      super.makeOptions(config);
      final FileParameter MATRIX_PARAM = new FileParameter(MATRIX_ID, FileParameter.FileType.INPUT_FILE);
      if(config.grab(MATRIX_PARAM)) {
        matrixfile = MATRIX_PARAM.getValue();
      }

      final ObjectParameter<DistanceParser> PARSER_PARAM = new ObjectParameter<>(PARSER_ID, DistanceParser.class, AsciiDistanceParser.class);
      if(config.grab(PARSER_PARAM)) {
        parser = PARSER_PARAM.instantiateClass(config);
      }
    }

    @Override
    protected FileBasedDoubleDistanceFunction makeInstance() {
      return new FileBasedDoubleDistanceFunction(parser, matrixfile);
    }
  }
}