001 /* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017 018 package org.apache.commons.math3.stat.clustering; 019 020 import java.io.Serializable; 021 import java.util.Arrays; 022 import java.util.Collection; 023 024 import org.apache.commons.math3.util.MathArrays; 025 026 /** 027 * A simple implementation of {@link Clusterable} for points with integer coordinates. 028 * @version $Id: EuclideanIntegerPoint.java 1416643 2012-12-03 19:37:14Z tn $ 029 * @since 2.0 030 */ 031 public class EuclideanIntegerPoint implements Clusterable<EuclideanIntegerPoint>, Serializable { 032 033 /** Serializable version identifier. */ 034 private static final long serialVersionUID = 3946024775784901369L; 035 036 /** Point coordinates. */ 037 private final int[] point; 038 039 /** 040 * Build an instance wrapping an integer array. 041 * <p>The wrapped array is referenced, it is <em>not</em> copied.</p> 042 * @param point the n-dimensional point in integer space 043 */ 044 public EuclideanIntegerPoint(final int[] point) { 045 this.point = point; 046 } 047 048 /** 049 * Get the n-dimensional point in integer space. 050 * @return a reference (not a copy!) to the wrapped array 051 */ 052 public int[] getPoint() { 053 return point; 054 } 055 056 /** {@inheritDoc} */ 057 public double distanceFrom(final EuclideanIntegerPoint p) { 058 return MathArrays.distance(point, p.getPoint()); 059 } 060 061 /** {@inheritDoc} */ 062 public EuclideanIntegerPoint centroidOf(final Collection<EuclideanIntegerPoint> points) { 063 int[] centroid = new int[getPoint().length]; 064 for (EuclideanIntegerPoint p : points) { 065 for (int i = 0; i < centroid.length; i++) { 066 centroid[i] += p.getPoint()[i]; 067 } 068 } 069 for (int i = 0; i < centroid.length; i++) { 070 centroid[i] /= points.size(); 071 } 072 return new EuclideanIntegerPoint(centroid); 073 } 074 075 /** {@inheritDoc} */ 076 @Override 077 public boolean equals(final Object other) { 078 if (!(other instanceof EuclideanIntegerPoint)) { 079 return false; 080 } 081 return Arrays.equals(point, ((EuclideanIntegerPoint) other).point); 082 } 083 084 /** {@inheritDoc} */ 085 @Override 086 public int hashCode() { 087 return Arrays.hashCode(point); 088 } 089 090 /** 091 * {@inheritDoc} 092 * @since 2.1 093 */ 094 @Override 095 public String toString() { 096 return Arrays.toString(point); 097 } 098 099 }