1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one or more 3 * contributor license agreements. See the NOTICE file distributed with 4 * this work for additional information regarding copyright ownership. 5 * The ASF licenses this file to You under the Apache License, Version 2.0 6 * (the "License"); you may not use this file except in compliance with 7 * the License. You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 */ 17 18 package org.apache.commons.math.stat.clustering; 19 20 import java.io.Serializable; 21 import java.util.Collection; 22 23 import org.apache.commons.math.util.MathUtils; 24 25 /** 26 * A simple implementation of {@link Clusterable} for points with integer coordinates. 27 * @version $Revision: 1042376 $ $Date: 2010-12-05 16:54:55 +0100 (dim. 05 dc. 2010) $ 28 * @since 2.0 29 */ 30 public class EuclideanIntegerPoint implements Clusterable<EuclideanIntegerPoint>, Serializable { 31 32 /** Serializable version identifier. */ 33 private static final long serialVersionUID = 3946024775784901369L; 34 35 /** Point coordinates. */ 36 private final int[] point; 37 38 /** 39 * Build an instance wrapping an integer array. 40 * <p>The wrapped array is referenced, it is <em>not</em> copied.</p> 41 * @param point the n-dimensional point in integer space 42 */ 43 public EuclideanIntegerPoint(final int[] point) { 44 this.point = point; 45 } 46 47 /** 48 * Get the n-dimensional point in integer space. 49 * @return a reference (not a copy!) to the wrapped array 50 */ 51 public int[] getPoint() { 52 return point; 53 } 54 55 /** {@inheritDoc} */ 56 public double distanceFrom(final EuclideanIntegerPoint p) { 57 return MathUtils.distance(point, p.getPoint()); 58 } 59 60 /** {@inheritDoc} */ 61 public EuclideanIntegerPoint centroidOf(final Collection<EuclideanIntegerPoint> points) { 62 int[] centroid = new int[getPoint().length]; 63 for (EuclideanIntegerPoint p : points) { 64 for (int i = 0; i < centroid.length; i++) { 65 centroid[i] += p.getPoint()[i]; 66 } 67 } 68 for (int i = 0; i < centroid.length; i++) { 69 centroid[i] /= points.size(); 70 } 71 return new EuclideanIntegerPoint(centroid); 72 } 73 74 /** {@inheritDoc} */ 75 @Override 76 public boolean equals(final Object other) { 77 if (!(other instanceof EuclideanIntegerPoint)) { 78 return false; 79 } 80 final int[] otherPoint = ((EuclideanIntegerPoint) other).getPoint(); 81 if (point.length != otherPoint.length) { 82 return false; 83 } 84 for (int i = 0; i < point.length; i++) { 85 if (point[i] != otherPoint[i]) { 86 return false; 87 } 88 } 89 return true; 90 } 91 92 /** {@inheritDoc} */ 93 @Override 94 public int hashCode() { 95 int hashCode = 0; 96 for (Integer i : point) { 97 hashCode += i.hashCode() * 13 + 7; 98 } 99 return hashCode; 100 } 101 102 /** 103 * {@inheritDoc} 104 * @since 2.1 105 */ 106 @Override 107 public String toString() { 108 final StringBuilder buff = new StringBuilder("("); 109 final int[] coordinates = getPoint(); 110 for (int i = 0; i < coordinates.length; i++) { 111 buff.append(coordinates[i]); 112 if (i < coordinates.length - 1) { 113 buff.append(","); 114 } 115 } 116 buff.append(")"); 117 return buff.toString(); 118 } 119 120 } 121