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Diffstat (limited to 'src/main/java/org/apache/commons/math/stat/clustering/EuclideanIntegerPoint.java')
-rw-r--r-- | src/main/java/org/apache/commons/math/stat/clustering/EuclideanIntegerPoint.java | 120 |
1 files changed, 120 insertions, 0 deletions
diff --git a/src/main/java/org/apache/commons/math/stat/clustering/EuclideanIntegerPoint.java b/src/main/java/org/apache/commons/math/stat/clustering/EuclideanIntegerPoint.java new file mode 100644 index 0000000..7fec0ff --- /dev/null +++ b/src/main/java/org/apache/commons/math/stat/clustering/EuclideanIntegerPoint.java @@ -0,0 +1,120 @@ +/* + * 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(); + } + +} |