1 | /*
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2 | * This program is free software; you can redistribute it and/or modify
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3 | * it under the terms of the GNU General Public License as published by
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4 | * the Free Software Foundation; either version 2 of the License, or
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5 | * (at your option) any later version.
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6 | *
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7 | * This program is distributed in the hope that it will be useful,
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8 | * but WITHOUT ANY WARRANTY; without even the implied warranty of
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9 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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10 | * GNU General Public License for more details.
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11 | *
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12 | * You should have received a copy of the GNU General Public License
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13 | * along with this program; if not, write to the Free Software
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14 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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15 | */
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16 |
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17 | /*
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18 | * Classifier.java
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19 | * Copyright (C) 1999 Eibe Frank, Len Trigg
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20 | *
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21 | */
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22 |
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23 | package weka.classifiers;
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24 |
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25 | import java.io.Serializable;
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26 | import weka.core.Instance;
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27 | import weka.core.Instances;
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28 | import weka.core.SerializedObject;
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29 | import weka.core.Utils;
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30 |
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31 |
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32 | /**
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33 | * Abstract classifier. All schemes for numeric or nominal prediction in
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34 | * Weka extend this class.
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35 | *
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36 | * @author Eibe Frank ([email protected])
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37 | * @author Len Trigg ([email protected])
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38 | * @version $Revision: 8815 $
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39 | */
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40 | public abstract class Classifier implements Cloneable, Serializable {
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41 |
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42 | /**
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43 | * Generates a classifier. Must initialize all fields of the classifier
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44 | * that are not being set via options (ie. multiple calls of buildClassifier
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45 | * must always lead to the same result). Must not change the dataset
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46 | * in any way.
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47 | *
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48 | * @param data set of instances serving as training data
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49 | * @exception Exception if the classifier has not been
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50 | * generated successfully
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51 | */
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52 | public abstract void buildClassifier(Instances data) throws Exception;
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53 |
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54 | /**
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55 | * Classifies a given instance.
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56 | *
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57 | * @param instance the instance to be classified
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58 | * @return index of the predicted class as a double
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59 | * if the class is nominal, otherwise the predicted value
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60 | * @exception Exception if instance could not be classified
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61 | * successfully
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62 | */
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63 | public abstract double classifyInstance(Instance instance) throws Exception;
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64 |
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65 |
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66 |
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67 | /**
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68 | * Creates a new instance of a classifier given it's class name and
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69 | * (optional) arguments to pass to it's setOptions method. If the
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70 | * classifier implements OptionHandler and the options parameter is
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71 | * non-null, the classifier will have it's options set.
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72 | *
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73 | * @param classifierName the fully qualified class name of the classifier
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74 | * @param options an array of options suitable for passing to setOptions. May
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75 | * be null.
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76 | * @return the newly created classifier, ready for use.
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77 | * @exception Exception if the classifier name is invalid, or the options
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78 | * supplied are not acceptable to the classifier
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79 | */
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80 | public static Classifier forName(String classifierName,
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81 | String [] options) throws Exception {
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82 |
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83 | return (Classifier)Utils.forName(Classifier.class,
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84 | classifierName,
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85 | options);
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86 | }
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87 |
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88 | /**
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89 | * Creates copies of the current classifier, which can then
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90 | * be used for boosting etc. Note that this method now uses
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91 | * Serialization to perform a deep copy, so the Classifier
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92 | * object must be fully Serializable. Any currently built model
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93 | * will now be copied as well.
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94 | *
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95 | * @param model an example classifier to copy
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96 | * @param num the number of classifiers copies to create.
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97 | * @return an array of classifiers.
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98 | * @exception Exception if an error occurs
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99 | */
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100 | public static Classifier [] makeCopies(Classifier model,
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101 | int num) throws Exception {
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102 |
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103 | if (model == null) {
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104 | throw new Exception("No model classifier set");
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105 | }
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106 | Classifier [] classifiers = new Classifier [num];
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107 | SerializedObject so = new SerializedObject(model);
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108 | for(int i = 0; i < classifiers.length; i++) {
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109 | classifiers[i] = (Classifier) so.getObject();
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110 | }
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111 | return classifiers;
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112 | }
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113 |
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114 | }
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115 |
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