001 /* =========================================================== 002 * JFreeChart : a free chart library for the Java(tm) platform 003 * =========================================================== 004 * 005 * (C) Copyright 2000-2006, by Object Refinery Limited and Contributors. 006 * 007 * Project Info: http://www.jfree.org/jfreechart/index.html 008 * 009 * This library is free software; you can redistribute it and/or modify it 010 * under the terms of the GNU Lesser General Public License as published by 011 * the Free Software Foundation; either version 2.1 of the License, or 012 * (at your option) any later version. 013 * 014 * This library is distributed in the hope that it will be useful, but 015 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 016 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public 017 * License for more details. 018 * 019 * You should have received a copy of the GNU Lesser General Public 020 * License along with this library; if not, write to the Free Software 021 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, 022 * USA. 023 * 024 * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 025 * in the United States and other countries.] 026 * 027 * ---------------------------- 028 * BoxAndWhiskerCalculator.java 029 * ---------------------------- 030 * (C) Copyright 2003-2006, by Object Refinery Limited and Contributors. 031 * 032 * Original Author: David Gilbert (for Object Refinery Limited); 033 * Contributor(s): -; 034 * 035 * $Id: BoxAndWhiskerCalculator.java,v 1.3.2.2 2006/11/16 11:19:47 mungady Exp $ 036 * 037 * Changes 038 * ------- 039 * 28-Aug-2003 : Version 1 (DG); 040 * 17-Nov-2003 : Fixed bug in calculations of outliers and median (DG); 041 * 10-Jan-2005 : Removed deprecated methods in preparation for 1.0.0 042 * release (DG); 043 * ------------- JFREECHART 1.0.x --------------------------------------------- 044 * 15-Nov-2006 : Cleaned up handling of null arguments, and null or NaN items 045 * in the list (DG); 046 * 047 */ 048 049 package org.jfree.data.statistics; 050 051 import java.util.ArrayList; 052 import java.util.Collections; 053 import java.util.Iterator; 054 import java.util.List; 055 056 /** 057 * A utility class that calculates the mean, median, quartiles Q1 and Q3, plus 058 * a list of outlier values...all from an arbitrary list of 059 * <code>Number</code> objects. 060 */ 061 public abstract class BoxAndWhiskerCalculator { 062 063 /** 064 * Calculates the statistics required for a {@link BoxAndWhiskerItem} 065 * from a list of <code>Number</code> objects. Any items in the list 066 * that are <code>null</code>, not an instance of <code>Number</code>, or 067 * equivalent to <code>Double.NaN</code>, will be ignored. 068 * 069 * @param values a list of numbers (a <code>null</code> list is not 070 * permitted). 071 * 072 * @return A box-and-whisker item. 073 */ 074 public static BoxAndWhiskerItem calculateBoxAndWhiskerStatistics( 075 List values) { 076 return calculateBoxAndWhiskerStatistics(values, true); 077 } 078 079 /** 080 * Calculates the statistics required for a {@link BoxAndWhiskerItem} 081 * from a list of <code>Number</code> objects. Any items in the list 082 * that are <code>null</code>, not an instance of <code>Number</code>, or 083 * equivalent to <code>Double.NaN</code>, will be ignored. 084 * 085 * @param values a list of numbers (a <code>null</code> list is not 086 * permitted). 087 * @param stripNullAndNaNItems a flag that controls the handling of null 088 * and NaN items. 089 * 090 * @return A box-and-whisker item. 091 * 092 * @since 1.0.3 093 */ 094 public static BoxAndWhiskerItem calculateBoxAndWhiskerStatistics( 095 List values, boolean stripNullAndNaNItems) { 096 097 if (values == null) { 098 throw new IllegalArgumentException("Null 'values' argument."); 099 } 100 101 List vlist; 102 if (stripNullAndNaNItems) { 103 vlist = new ArrayList(values.size()); 104 Iterator iterator = values.listIterator(); 105 while (iterator.hasNext()) { 106 Object obj = iterator.next(); 107 if (obj instanceof Number) { 108 Number n = (Number) obj; 109 double v = n.doubleValue(); 110 if (!Double.isNaN(v)) { 111 vlist.add(n); 112 } 113 } 114 } 115 } 116 else { 117 vlist = values; 118 } 119 Collections.sort(vlist); 120 121 double mean = Statistics.calculateMean(vlist, false); 122 double median = Statistics.calculateMedian(vlist, false); 123 double q1 = calculateQ1(vlist); 124 double q3 = calculateQ3(vlist); 125 126 double interQuartileRange = q3 - q1; 127 128 double upperOutlierThreshold = q3 + (interQuartileRange * 1.5); 129 double lowerOutlierThreshold = q1 - (interQuartileRange * 1.5); 130 131 double upperFaroutThreshold = q3 + (interQuartileRange * 2.0); 132 double lowerFaroutThreshold = q1 - (interQuartileRange * 2.0); 133 134 double minRegularValue = Double.POSITIVE_INFINITY; 135 double maxRegularValue = Double.NEGATIVE_INFINITY; 136 double minOutlier = Double.POSITIVE_INFINITY; 137 double maxOutlier = Double.NEGATIVE_INFINITY; 138 List outliers = new ArrayList(); 139 140 Iterator iterator = vlist.iterator(); 141 while (iterator.hasNext()) { 142 Number number = (Number) iterator.next(); 143 double value = number.doubleValue(); 144 if (value > upperOutlierThreshold) { 145 outliers.add(number); 146 if (value > maxOutlier && value <= upperFaroutThreshold) { 147 maxOutlier = value; 148 } 149 } 150 else if (value < lowerOutlierThreshold) { 151 outliers.add(number); 152 if (value < minOutlier && value >= lowerFaroutThreshold) { 153 minOutlier = value; 154 } 155 } 156 else { 157 minRegularValue = Math.min(minRegularValue, value); 158 maxRegularValue = Math.max(maxRegularValue, value); 159 } 160 minOutlier = Math.min(minOutlier, minRegularValue); 161 maxOutlier = Math.max(maxOutlier, maxRegularValue); 162 } 163 164 return new BoxAndWhiskerItem(new Double(mean), new Double(median), 165 new Double(q1), new Double(q3), new Double(minRegularValue), 166 new Double(maxRegularValue), new Double(minOutlier), 167 new Double(maxOutlier), outliers); 168 169 } 170 171 /** 172 * Calculates the first quartile for a list of numbers in ascending order. 173 * If the items in the list are not in ascending order, the result is 174 * unspecified. If the list contains items that are <code>null</code>, not 175 * an instance of <code>Number</code>, or equivalent to 176 * <code>Double.NaN</code>, the result is unspecified. 177 * 178 * @param values the numbers in ascending order (<code>null</code> not 179 * permitted). 180 * 181 * @return The first quartile. 182 */ 183 public static double calculateQ1(List values) { 184 if (values == null) { 185 throw new IllegalArgumentException("Null 'values' argument."); 186 } 187 188 double result = Double.NaN; 189 int count = values.size(); 190 if (count > 0) { 191 if (count % 2 == 1) { 192 if (count > 1) { 193 result = Statistics.calculateMedian(values, 0, count / 2); 194 } 195 else { 196 result = Statistics.calculateMedian(values, 0, 0); 197 } 198 } 199 else { 200 result = Statistics.calculateMedian(values, 0, count / 2 - 1); 201 } 202 203 } 204 return result; 205 } 206 207 /** 208 * Calculates the third quartile for a list of numbers in ascending order. 209 * If the items in the list are not in ascending order, the result is 210 * unspecified. If the list contains items that are <code>null</code>, not 211 * an instance of <code>Number</code>, or equivalent to 212 * <code>Double.NaN</code>, the result is unspecified. 213 * 214 * @param values the list of values (<code>null</code> not permitted). 215 * 216 * @return The third quartile. 217 */ 218 public static double calculateQ3(List values) { 219 if (values == null) { 220 throw new IllegalArgumentException("Null 'values' argument."); 221 } 222 double result = Double.NaN; 223 int count = values.size(); 224 if (count > 0) { 225 if (count % 2 == 1) { 226 if (count > 1) { 227 result = Statistics.calculateMedian(values, count / 2, 228 count - 1); 229 } 230 else { 231 result = Statistics.calculateMedian(values, 0, 0); 232 } 233 } 234 else { 235 result = Statistics.calculateMedian(values, count / 2, 236 count - 1); 237 } 238 } 239 return result; 240 } 241 242 }