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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership.
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* The ASF licenses this file to You under the Apache License, Version 2.0
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* (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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* http://www.apache.org/licenses/LICENSE-2.0
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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package org.apache.commons.math.stat.clustering;
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import java.io.Serializable;
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import java.util.Collection;
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import org.apache.commons.math.util.MathUtils;
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* A simple implementation of {@link Clusterable} for points with integer coordinates.
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* @version $Revision: 795984 $ $Date: 2009-07-20 16:13:24 -0400 (Mon, 20 Jul 2009) $
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public class EuclideanIntegerPoint implements Clusterable<EuclideanIntegerPoint>, Serializable {
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/** Serializable version identifier. */
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private static final long serialVersionUID = 3946024775784901369L;
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/** Point coordinates. */
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private final int[] point;
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* Build an instance wrapping an integer array.
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* <p>The wrapped array is referenced, it is <em>not</em> copied.</p>
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* @param point the n-dimensional point in integer space
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public EuclideanIntegerPoint(final int[] point) {
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* Get the n-dimensional point in integer space.
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* @return a reference (not a copy!) to the wrapped array
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public int[] getPoint() {
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public double distanceFrom(final EuclideanIntegerPoint p) {
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return MathUtils.distance(point, p.getPoint());
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public EuclideanIntegerPoint centroidOf(final Collection<EuclideanIntegerPoint> points) {
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int[] centroid = new int[getPoint().length];
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for (EuclideanIntegerPoint p : points) {
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for (int i = 0; i < centroid.length; i++) {
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centroid[i] += p.getPoint()[i];
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for (int i = 0; i < centroid.length; i++) {
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centroid[i] /= points.size();
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return new EuclideanIntegerPoint(centroid);
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public boolean equals(final Object other) {
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if (!(other instanceof EuclideanIntegerPoint)) {
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final int[] otherPoint = ((EuclideanIntegerPoint) other).getPoint();
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if (point.length != otherPoint.length) {
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for (int i = 0; i < point.length; i++) {
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if (point[i] != otherPoint[i]) {
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public int hashCode() {
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for (Integer i : point) {
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hashCode += i.hashCode() * 13 + 7;