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1   /**
2    * Copyright (c) 2011, The University of Southampton and the individual contributors.
3    * All rights reserved.
4    *
5    * Redistribution and use in source and binary forms, with or without modification,
6    * are permitted provided that the following conditions are met:
7    *
8    *   * 	Redistributions of source code must retain the above copyright notice,
9    * 	this list of conditions and the following disclaimer.
10   *
11   *   *	Redistributions in binary form must reproduce the above copyright notice,
12   * 	this list of conditions and the following disclaimer in the documentation
13   * 	and/or other materials provided with the distribution.
14   *
15   *   *	Neither the name of the University of Southampton nor the names of its
16   * 	contributors may be used to endorse or promote products derived from this
17   * 	software without specific prior written permission.
18   *
19   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
20   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
21   * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
22   * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
23   * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
24   * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
25   * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
26   * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
28   * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29   */
30  package org.openimaj.ml.clustering.spectral;
31  
32  import org.apache.log4j.Logger;
33  import org.openimaj.feature.DoubleFV;
34  import org.openimaj.feature.DoubleFVComparison;
35  import org.openimaj.feature.FeatureExtractor;
36  import org.openimaj.ml.clustering.SimilarityClusterer;
37  
38  import ch.akuhn.matrix.SparseMatrix;
39  
40  /**
41   * Wraps the functionality of a {@link SimilarityClusterer} around a dataset
42   * 
43   * @author Sina Samangooei (ss@ecs.soton.ac.uk)
44   *
45   * @param <T>
46   */
47  public class NormalisedSimilarityDoubleClustererWrapper<T> extends DoubleFVSimilarityFunction<T> {
48  
49  	private double eps;
50  
51  	/**
52  	 *
53  	 * @param extractor
54  	 * @param eps
55  	 */
56  	public NormalisedSimilarityDoubleClustererWrapper(FeatureExtractor<DoubleFV, T> extractor, double eps) {
57  		super(extractor);
58  		this.eps = eps;
59  	}
60  
61  	Logger logger = Logger.getLogger(NormalisedSimilarityDoubleClustererWrapper.class);
62  
63  	@Override
64  	protected SparseMatrix similarity() {
65  		final SparseMatrix mat = new SparseMatrix(feats.length, feats.length);
66  		final DoubleFVComparison dist = DoubleFVComparison.EUCLIDEAN;
67  		double maxD = 0;
68  		for (int i = 0; i < feats.length; i++) {
69  			for (int j = i; j < feats.length; j++) {
70  				double d = dist.compare(feats[i], feats[j]);
71  				if (d > eps)
72  					d = Double.NaN;
73  				else {
74  					maxD = Math.max(d, maxD);
75  				}
76  				mat.put(i, j, d);
77  				mat.put(j, i, d);
78  			}
79  		}
80  		final SparseMatrix mat_norm = new SparseMatrix(feats.length, feats.length);
81  		for (int i = 0; i < feats.length; i++) {
82  			for (int j = i; j < feats.length; j++) {
83  				double d = mat.get(i, j);
84  				if (Double.isNaN(d)) {
85  					continue;
86  				}
87  				else {
88  					d /= maxD;
89  				}
90  				mat_norm.put(i, j, 1 - d);
91  				mat_norm.put(j, i, 1 - d);
92  			}
93  		}
94  		return mat_norm;
95  	}
96  
97  }