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.summary; 18dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond 19dee0849a9704d532af0b550146cbafbaa6ee1d19Raymondimport java.io.Serializable; 20dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond 21dee0849a9704d532af0b550146cbafbaa6ee1d19Raymondimport org.apache.commons.math.stat.descriptive.AbstractStorelessUnivariateStatistic; 22dee0849a9704d532af0b550146cbafbaa6ee1d19Raymondimport org.apache.commons.math.util.FastMath; 23dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond 24dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond/** 25dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * Returns the sum of the natural logs for this collection of values. 26dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * <p> 27dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * Uses {@link java.lang.Math#log(double)} to compute the logs. Therefore, 28dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * <ul> 29dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * <li>If any of values are < 0, the result is <code>NaN.</code></li> 30dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * <li>If all values are non-negative and less than 31dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * <code>Double.POSITIVE_INFINITY</code>, but at least one value is 0, the 32dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * result is <code>Double.NEGATIVE_INFINITY.</code></li> 33dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * <li>If both <code>Double.POSITIVE_INFINITY</code> and 34dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * <code>Double.NEGATIVE_INFINITY</code> are among the values, the result is 35dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * <code>NaN.</code></li> 36dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * </ul></p> 37dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * <p> 38dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * <strong>Note that this implementation is not synchronized.</strong> If 39dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * multiple threads access an instance of this class concurrently, and at least 40dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * one of the threads invokes the <code>increment()</code> or 41dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * <code>clear()</code> method, it must be synchronized externally.</p> 42dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * 43dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * @version $Revision: 1006299 $ $Date: 2010-10-10 16:47:17 +0200 (dim. 10 oct. 2010) $ 44dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond */ 45dee0849a9704d532af0b550146cbafbaa6ee1d19Raymondpublic class SumOfLogs extends AbstractStorelessUnivariateStatistic implements Serializable { 46dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond 47dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond /** Serializable version identifier */ 48dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond private static final long serialVersionUID = -370076995648386763L; 49dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond 50dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond /**Number of values that have been added */ 51dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond private int n; 52dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond 53dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond /** 54dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * The currently running value 55dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond */ 56dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond private double value; 57dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond 58dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond /** 59dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * Create a SumOfLogs instance 60dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond */ 61dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond public SumOfLogs() { 62dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond value = 0d; 63dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond n = 0; 64dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond } 65dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond 66dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond /** 67dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * Copy constructor, creates a new {@code SumOfLogs} identical 68dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * to the {@code original} 69dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * 70dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * @param original the {@code SumOfLogs} instance to copy 71dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond */ 72dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond public SumOfLogs(SumOfLogs original) { 73dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond copy(original, this); 74dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond } 75dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond 76dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond /** 77dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * {@inheritDoc} 78dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond */ 79dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond @Override 80dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond public void increment(final double d) { 81dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond value += FastMath.log(d); 82dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond n++; 83dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond } 84dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond 85dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond /** 86dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * {@inheritDoc} 87dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond */ 88dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond @Override 89dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond public double getResult() { 90dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond if (n > 0) { 91dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond return value; 92dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond } else { 93dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond return Double.NaN; 94dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond } 95dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond } 96dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond 97dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond /** 98dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * {@inheritDoc} 99dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond */ 100dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond public long getN() { 101dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond return n; 102dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond } 103dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond 104dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond /** 105dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * {@inheritDoc} 106dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond */ 107dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond @Override 108dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond public void clear() { 109dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond value = 0d; 110dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond n = 0; 111dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond } 112dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond 113dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond /** 114dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * Returns the sum of the natural logs of the entries in the specified portion of 115dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * the input array, or <code>Double.NaN</code> if the designated subarray 116dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * is empty. 117dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * <p> 118dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * Throws <code>IllegalArgumentException</code> if the array is null.</p> 119dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * <p> 120dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * See {@link SumOfLogs}.</p> 121dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * 122dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * @param values the input array 123dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * @param begin index of the first array element to include 124dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * @param length the number of elements to include 125dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * @return the sum of the natural logs of the values or Double.NaN if 126dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * length = 0 127dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * @throws IllegalArgumentException if the array is null or the array index 128dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * parameters are not valid 129dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond */ 130dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond @Override 131dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond public double evaluate(final double[] values, final int begin, final int length) { 132dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond double sumLog = Double.NaN; 133dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond if (test(values, begin, length)) { 134dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond sumLog = 0.0; 135dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond for (int i = begin; i < begin + length; i++) { 136dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond sumLog += FastMath.log(values[i]); 137dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond } 138dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond } 139dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond return sumLog; 140dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond } 141dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond 142dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond /** 143dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * {@inheritDoc} 144dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond */ 145dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond @Override 146dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond public SumOfLogs copy() { 147dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond SumOfLogs result = new SumOfLogs(); 148dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond copy(this, result); 149dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond return result; 150dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond } 151dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond 152dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond /** 153dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * Copies source to dest. 154dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * <p>Neither source nor dest can be null.</p> 155dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * 156dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * @param source SumOfLogs to copy 157dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * @param dest SumOfLogs to copy to 158dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond * @throws NullPointerException if either source or dest is null 159dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond */ 160dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond public static void copy(SumOfLogs source, SumOfLogs dest) { 161dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond dest.setData(source.getDataRef()); 162dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond dest.n = source.n; 163dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond dest.value = source.value; 164dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond } 165dee0849a9704d532af0b550146cbafbaa6ee1d19Raymond} 166