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 */ 017package org.apache.commons.math3.ml.clustering; 018 019import java.util.Collection; 020import java.util.List; 021 022import org.apache.commons.math3.exception.ConvergenceException; 023import org.apache.commons.math3.exception.MathIllegalArgumentException; 024import org.apache.commons.math3.ml.distance.DistanceMeasure; 025 026/** 027 * Base class for clustering algorithms. 028 * 029 * @param <T> the type of points that can be clustered 030 * @since 3.2 031 */ 032public abstract class Clusterer<T extends Clusterable> { 033 034 /** The distance measure to use. */ 035 private DistanceMeasure measure; 036 037 /** 038 * Build a new clusterer with the given {@link DistanceMeasure}. 039 * 040 * @param measure the distance measure to use 041 */ 042 protected Clusterer(final DistanceMeasure measure) { 043 this.measure = measure; 044 } 045 046 /** 047 * Perform a cluster analysis on the given set of {@link Clusterable} instances. 048 * 049 * @param points the set of {@link Clusterable} instances 050 * @return a {@link List} of clusters 051 * @throws MathIllegalArgumentException if points are null or the number of 052 * data points is not compatible with this clusterer 053 * @throws ConvergenceException if the algorithm has not yet converged after 054 * the maximum number of iterations has been exceeded 055 */ 056 public abstract List<? extends Cluster<T>> cluster(Collection<T> points) 057 throws MathIllegalArgumentException, ConvergenceException; 058 059 /** 060 * Returns the {@link DistanceMeasure} instance used by this clusterer. 061 * 062 * @return the distance measure 063 */ 064 public DistanceMeasure getDistanceMeasure() { 065 return measure; 066 } 067 068 /** 069 * Calculates the distance between two {@link Clusterable} instances 070 * with the configured {@link DistanceMeasure}. 071 * 072 * @param p1 the first clusterable 073 * @param p2 the second clusterable 074 * @return the distance between the two clusterables 075 */ 076 protected double distance(final Clusterable p1, final Clusterable p2) { 077 return measure.compute(p1.getPoint(), p2.getPoint()); 078 } 079 080}