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 package org.apache.commons.math3.stat.clustering; 018 019 import java.io.Serializable; 020 import java.util.Collection; 021 import java.util.Arrays; 022 023 import org.apache.commons.math3.util.MathArrays; 024 025 /** 026 * A simple implementation of {@link Clusterable} for points with double coordinates. 027 * @version $Id: EuclideanDoublePoint.java 1413096 2012-11-23 22:34:05Z erans $ 028 * @since 3.1 029 */ 030 public class EuclideanDoublePoint implements Clusterable<EuclideanDoublePoint>, Serializable { 031 032 /** Serializable version identifier. */ 033 private static final long serialVersionUID = 8026472786091227632L; 034 035 /** Point coordinates. */ 036 private final double[] point; 037 038 /** 039 * Build an instance wrapping an integer array. 040 * <p> 041 * The wrapped array is referenced, it is <em>not</em> copied. 042 * 043 * @param point the n-dimensional point in integer space 044 */ 045 public EuclideanDoublePoint(final double[] point) { 046 this.point = point; 047 } 048 049 /** {@inheritDoc} */ 050 public EuclideanDoublePoint centroidOf(final Collection<EuclideanDoublePoint> points) { 051 final double[] centroid = new double[getPoint().length]; 052 for (final EuclideanDoublePoint p : points) { 053 for (int i = 0; i < centroid.length; i++) { 054 centroid[i] += p.getPoint()[i]; 055 } 056 } 057 for (int i = 0; i < centroid.length; i++) { 058 centroid[i] /= points.size(); 059 } 060 return new EuclideanDoublePoint(centroid); 061 } 062 063 /** {@inheritDoc} */ 064 public double distanceFrom(final EuclideanDoublePoint p) { 065 return MathArrays.distance(point, p.getPoint()); 066 } 067 068 /** {@inheritDoc} */ 069 @Override 070 public boolean equals(final Object other) { 071 if (!(other instanceof EuclideanDoublePoint)) { 072 return false; 073 } 074 return Arrays.equals(point, ((EuclideanDoublePoint) other).point); 075 } 076 077 /** 078 * Get the n-dimensional point in integer space. 079 * 080 * @return a reference (not a copy!) to the wrapped array 081 */ 082 public double[] getPoint() { 083 return point; 084 } 085 086 /** {@inheritDoc} */ 087 @Override 088 public int hashCode() { 089 return Arrays.hashCode(point); 090 } 091 092 /** {@inheritDoc} */ 093 @Override 094 public String toString() { 095 return Arrays.toString(point); 096 } 097 098 }