1 | package org.greenstone.mars;
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2 |
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3 | import weka.core.Instance;
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4 | import weka.core.Instances;
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5 | import weka.core.converters.ConverterUtils.DataSource;
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6 |
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7 | import weka.core.neighboursearch.LinearNNSearch;
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8 | import weka.core.neighboursearch.NearestNeighbourSearch;
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9 | //import weka.core.neighboursearch.KDTree;
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10 |
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11 | // Based on StackOverflow:
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12 | // https://stackoverflow.com/questions/31350506/how-to-calculate-the-nearest-neighbors-using-weka-from-the-command-line
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13 |
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14 | public class WekaFindInstanceKNN
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15 | {
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16 |
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17 | public static Instances loadDataset(String input_filename)
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18 | {
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19 | Instances instances = null;
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20 |
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21 | try {
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22 | DataSource source = new DataSource(input_filename);
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23 | instances = source.getDataSet();
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24 | }
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25 | catch (Exception e) {
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26 | e.printStackTrace();
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27 | }
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28 |
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29 | return instances;
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30 | }
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31 |
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32 | public static NearestNeighbourSearch initKNN(Instances instances)
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33 | {
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34 | LinearNNSearch knn = new LinearNNSearch(instances);
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35 |
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36 | return knn;
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37 | }
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38 |
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39 | public static void findNearestKNN(NearestNeighbourSearch knn, Instance sample_instance, int k_nearest)
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40 | {
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41 | try {
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42 | Instances nearest_instances= knn.kNearestNeighbours(sample_instance, k_nearest);
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43 |
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44 | //cycle through the instances and printout the nearestneighbors
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45 |
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46 | System.out.println("\n" + sample_instance);
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47 | for(int i =0; i<k_nearest; i++) {
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48 | System.out.println("\t" + nearest_instances.instance(i));
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49 | }
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50 | }
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51 | catch (Exception e) {
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52 | e.printStackTrace();
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53 | }
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54 |
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55 | }
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56 |
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57 |
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58 | public static void main(String[] args)
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59 | {
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60 | if (args.length != 2) {
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61 | System.err.println("Usage: k-nearest-num file.{arff,csv}");
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62 | System.exit(1);
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63 | }
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64 |
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65 | String k_nearest_str = args[0];
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66 | String input_filename = args[1];
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67 |
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68 | int k_nearest = Integer.parseInt(k_nearest_str);
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69 |
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70 | System.out.println("Weka Command Line Find Nearest " + k_nearest_str
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71 | + " Neighbors for each Instance in " + input_filename);
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72 |
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73 | Instances instances = loadDataset(input_filename);
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74 | NearestNeighbourSearch knn = initKNN(instances);
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75 |
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76 | /*
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77 | DataSource source = new DataSource(input_filename);
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78 | Instances instances = source.getDataSet();
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79 |
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80 | LinearNNSearch knn = new LinearNNSearch(instances);
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81 | //KDTree knn = new KDTree(instances);
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82 | */
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83 |
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84 | //cycle through the dataset and get instances for the nearestneighbors
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85 |
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86 | int num_instances = instances.numInstances();
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87 | for(int j=0; j<num_instances; j++) {
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88 | //Instances nearestInstances= knn.kNearestNeighbours(instances.instance(j), k_nearest);
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89 |
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90 | Instance sample_instance = instances.instance(j);
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91 | findNearestKNN(knn,sample_instance,k_nearest);
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92 | }
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93 | }
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94 | }
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