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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.commons.math.stat.clustering;
import java.io.Serializable;
import java.util.Collection;
import org.apache.commons.math.util.MathUtils;
/**
* A simple implementation of {@link Clusterable} for points with integer coordinates.
* @version $Revision: 1042376 $ $Date: 2010-12-05 16:54:55 +0100 (dim. 05 déc. 2010) $
* @since 2.0
*/
public class EuclideanIntegerPoint implements Clusterable<EuclideanIntegerPoint>, Serializable {
/** Serializable version identifier. */
private static final long serialVersionUID = 3946024775784901369L;
/** Point coordinates. */
private final int[] point;
/**
* Build an instance wrapping an integer array.
* <p>The wrapped array is referenced, it is <em>not</em> copied.</p>
* @param point the n-dimensional point in integer space
*/
public EuclideanIntegerPoint(final int[] point) {
this.point = point;
}
/**
* Get the n-dimensional point in integer space.
* @return a reference (not a copy!) to the wrapped array
*/
public int[] getPoint() {
return point;
}
/** {@inheritDoc} */
public double distanceFrom(final EuclideanIntegerPoint p) {
return MathUtils.distance(point, p.getPoint());
}
/** {@inheritDoc} */
public EuclideanIntegerPoint centroidOf(final Collection<EuclideanIntegerPoint> points) {
int[] centroid = new int[getPoint().length];
for (EuclideanIntegerPoint p : points) {
for (int i = 0; i < centroid.length; i++) {
centroid[i] += p.getPoint()[i];
}
}
for (int i = 0; i < centroid.length; i++) {
centroid[i] /= points.size();
}
return new EuclideanIntegerPoint(centroid);
}
/** {@inheritDoc} */
@Override
public boolean equals(final Object other) {
if (!(other instanceof EuclideanIntegerPoint)) {
return false;
}
final int[] otherPoint = ((EuclideanIntegerPoint) other).getPoint();
if (point.length != otherPoint.length) {
return false;
}
for (int i = 0; i < point.length; i++) {
if (point[i] != otherPoint[i]) {
return false;
}
}
return true;
}
/** {@inheritDoc} */
@Override
public int hashCode() {
int hashCode = 0;
for (Integer i : point) {
hashCode += i.hashCode() * 13 + 7;
}
return hashCode;
}
/**
* {@inheritDoc}
* @since 2.1
*/
@Override
public String toString() {
final StringBuilder buff = new StringBuilder("(");
final int[] coordinates = getPoint();
for (int i = 0; i < coordinates.length; i++) {
buff.append(coordinates[i]);
if (i < coordinates.length - 1) {
buff.append(",");
}
}
buff.append(")");
return buff.toString();
}
}
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