1dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond/* 2dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * Licensed to the Apache Software Foundation (ASF) under one or more 3dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * contributor license agreements. See the NOTICE file distributed with 4dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * this work for additional information regarding copyright ownership. 5dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * The ASF licenses this file to You under the Apache License, Version 2.0 6dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * (the "License"); you may not use this file except in compliance with 7dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * the License. You may obtain a copy of the License at 8dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * 9dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * http://www.apache.org/licenses/LICENSE-2.0 10dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * 11dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * Unless required by applicable law or agreed to in writing, software 12dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * distributed under the License is distributed on an "AS IS" BASIS, 13dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * See the License for the specific language governing permissions and 15dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * limitations under the License. 16dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond */ 17dee0849a9704d532af0b550146cbafbaa6ee1d19Raymondpackage org.apache.commons.math.stat.descriptive.moment; 18dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond 19dee0849a9704d532af0b550146cbafbaa6ee1d19Raymondimport java.io.Serializable; 20dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond 21dee0849a9704d532af0b550146cbafbaa6ee1d19Raymondimport org.apache.commons.math.MathRuntimeException; 22dee0849a9704d532af0b550146cbafbaa6ee1d19Raymondimport org.apache.commons.math.exception.util.LocalizedFormats; 23dee0849a9704d532af0b550146cbafbaa6ee1d19Raymondimport org.apache.commons.math.stat.descriptive.AbstractStorelessUnivariateStatistic; 24dee0849a9704d532af0b550146cbafbaa6ee1d19Raymondimport org.apache.commons.math.stat.descriptive.StorelessUnivariateStatistic; 25dee0849a9704d532af0b550146cbafbaa6ee1d19Raymondimport org.apache.commons.math.stat.descriptive.summary.SumOfLogs; 26dee0849a9704d532af0b550146cbafbaa6ee1d19Raymondimport org.apache.commons.math.util.FastMath; 27dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond 28dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond/** 29dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * Returns the <a href="http://www.xycoon.com/geometric_mean.htm"> 30dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * geometric mean </a> of the available values. 31dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * <p> 32dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * Uses a {@link SumOfLogs} instance to compute sum of logs and returns 33dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * <code> exp( 1/n (sum of logs) ).</code> Therefore, </p> 34dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * <ul> 35dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * <li>If any of values are < 0, the result is <code>NaN.</code></li> 36dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * <li>If all values are non-negative and less than 37dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * <code>Double.POSITIVE_INFINITY</code>, but at least one value is 0, the 38dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * result is <code>0.</code></li> 39dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * <li>If both <code>Double.POSITIVE_INFINITY</code> and 40dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * <code>Double.NEGATIVE_INFINITY</code> are among the values, the result is 41dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * <code>NaN.</code></li> 42dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * </ul> </p> 43dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * <p> 44dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * <strong>Note that this implementation is not synchronized.</strong> If 45dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * multiple threads access an instance of this class concurrently, and at least 46dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * one of the threads invokes the <code>increment()</code> or 47dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * <code>clear()</code> method, it must be synchronized externally.</p> 48dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * 49dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * 50dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * @version $Revision: 1006299 $ $Date: 2010-10-10 16:47:17 +0200 (dim. 10 oct. 2010) $ 51dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond */ 52dee0849a9704d532af0b550146cbafbaa6ee1d19Raymondpublic class GeometricMean extends AbstractStorelessUnivariateStatistic implements Serializable { 53dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond 54dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond /** Serializable version identifier */ 55dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond private static final long serialVersionUID = -8178734905303459453L; 56dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond 57dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond /** Wrapped SumOfLogs instance */ 58dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond private StorelessUnivariateStatistic sumOfLogs; 59dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond 60dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond /** 61dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * Create a GeometricMean instance 62dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond */ 63dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond public GeometricMean() { 64dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond sumOfLogs = new SumOfLogs(); 65dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond } 66dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond 67dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond /** 68dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * Copy constructor, creates a new {@code GeometricMean} identical 69dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * to the {@code original} 70dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * 71dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * @param original the {@code GeometricMean} instance to copy 72dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond */ 73dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond public GeometricMean(GeometricMean original) { 74dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond super(); 75dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond copy(original, this); 76dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond } 77dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond 78dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond /** 79dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * Create a GeometricMean instance using the given SumOfLogs instance 80dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * @param sumOfLogs sum of logs instance to use for computation 81dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond */ 82dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond public GeometricMean(SumOfLogs sumOfLogs) { 83dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond this.sumOfLogs = sumOfLogs; 84dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond } 85dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond 86dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond /** 87dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * {@inheritDoc} 88dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond */ 89dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond @Override 90dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond public GeometricMean copy() { 91dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond GeometricMean result = new GeometricMean(); 92dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond copy(this, result); 93dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond return result; 94dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond } 95dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond 96dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond /** 97dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * {@inheritDoc} 98dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond */ 99dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond @Override 100dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond public void increment(final double d) { 101dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond sumOfLogs.increment(d); 102dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond } 103dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond 104dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond /** 105dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * {@inheritDoc} 106dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond */ 107dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond @Override 108dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond public double getResult() { 109dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond if (sumOfLogs.getN() > 0) { 110dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond return FastMath.exp(sumOfLogs.getResult() / sumOfLogs.getN()); 111dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond } else { 112dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond return Double.NaN; 113dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond } 114dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond } 115dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond 116dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond /** 117dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * {@inheritDoc} 118dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond */ 119dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond @Override 120dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond public void clear() { 121dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond sumOfLogs.clear(); 122dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond } 123dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond 124dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond /** 125dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * Returns the geometric mean of the entries in the specified portion 126dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * of the input array. 127dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * <p> 128dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * See {@link GeometricMean} for details on the computing algorithm.</p> 129dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * <p> 130dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * Throws <code>IllegalArgumentException</code> if the array is null.</p> 131dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * 132dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * @param values input array containing the values 133dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * @param begin first array element to include 134dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * @param length the number of elements to include 135dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * @return the geometric mean or Double.NaN if length = 0 or 136dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * any of the values are <= 0. 137dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * @throws IllegalArgumentException if the input array is null or the array 138dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * index parameters are not valid 139dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond */ 140dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond @Override 141dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond public double evaluate( 142dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond final double[] values, final int begin, final int length) { 143dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond return FastMath.exp( 144dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond sumOfLogs.evaluate(values, begin, length) / length); 145dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond } 146dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond 147dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond /** 148dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * {@inheritDoc} 149dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond */ 150dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond public long getN() { 151dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond return sumOfLogs.getN(); 152dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond } 153dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond 154dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond /** 155dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * <p>Sets the implementation for the sum of logs.</p> 156dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * <p>This method must be activated before any data has been added - i.e., 157dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * before {@link #increment(double) increment} has been used to add data; 158dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * otherwise an IllegalStateException will be thrown.</p> 159dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * 160dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * @param sumLogImpl the StorelessUnivariateStatistic instance to use 161dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * for computing the log sum 162dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * @throws IllegalStateException if data has already been added 163dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * (i.e if n > 0) 164dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond */ 165dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond public void setSumLogImpl( 166dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond StorelessUnivariateStatistic sumLogImpl) { 167dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond checkEmpty(); 168dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond this.sumOfLogs = sumLogImpl; 169dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond } 170dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond 171dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond /** 172dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * Returns the currently configured sum of logs implementation 173dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * 174dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * @return the StorelessUnivariateStatistic implementing the log sum 175dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond */ 176dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond public StorelessUnivariateStatistic getSumLogImpl() { 177dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond return sumOfLogs; 178dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond } 179dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond 180dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond /** 181dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * Copies source to dest. 182dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * <p>Neither source nor dest can be null.</p> 183dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * 184dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * @param source GeometricMean to copy 185dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * @param dest GeometricMean to copy to 186dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * @throws NullPointerException if either source or dest is null 187dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond */ 188dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond public static void copy(GeometricMean source, GeometricMean dest) { 189dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond dest.setData(source.getDataRef()); 190dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond dest.sumOfLogs = source.sumOfLogs.copy(); 191dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond } 192dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond 193dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond 194dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond /** 195dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * Throws IllegalStateException if n > 0. 196dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond */ 197dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond private void checkEmpty() { 198dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond if (getN() > 0) { 199dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond throw MathRuntimeException.createIllegalStateException( 200dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond LocalizedFormats.VALUES_ADDED_BEFORE_CONFIGURING_STATISTIC, 201dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond getN()); 202dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond } 203dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond } 204dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond 205dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond} 206