/* ===========================================================
* JFreeChart : a free chart library for the Java(tm) platform
* ===========================================================
*
* (C) Copyright 2000-2011, by Object Refinery Limited and Contributors.
*
* Project Info: http://www.jfree.org/jfreechart/index.html
*
* This library is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 2.1 of the License, or
* (at your option) any later version.
*
* This library is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
* License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
* USA.
*
* [Oracle and Java are registered trademarks of Oracle and/or its affiliates.
* Other names may be trademarks of their respective owners.]
*
* ----------------------------
* BoxAndWhiskerCalculator.java
* ----------------------------
* (C) Copyright 2003-2008, by Object Refinery Limited and Contributors.
*
* Original Author: David Gilbert (for Object Refinery Limited);
* Contributor(s): -;
*
* Changes
* -------
* 28-Aug-2003 : Version 1 (DG);
* 17-Nov-2003 : Fixed bug in calculations of outliers and median (DG);
* 10-Jan-2005 : Removed deprecated methods in preparation for 1.0.0
* release (DG);
* ------------- JFREECHART 1.0.x ---------------------------------------------
* 15-Nov-2006 : Cleaned up handling of null arguments, and null or NaN items
* in the list (DG);
*
*/
package org.jfree.data.statistics;
import org.jfree.chart.axis.NumberComparator;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
/**
* A utility class that calculates the mean, median, quartiles Q1 and Q3, plus
* a list of outlier values...all from an arbitrary list of
* <code>Number</code> objects.
*/
public abstract class BoxAndWhiskerCalculator {
/**
* Calculates the statistics required for a {@link BoxAndWhiskerItem}
* from a list of <code>Number</code> objects. Any items in the list
* that are <code>null</code>, not an instance of <code>Number</code>, or
* equivalent to <code>Double.NaN</code>, will be ignored.
*
* @param values a list of numbers (a <code>null</code> list is not
* permitted).
*
* @return A box-and-whisker item.
*/
public static BoxAndWhiskerItem calculateBoxAndWhiskerStatistics(
List<Number> values) {
return calculateBoxAndWhiskerStatistics(values, true);
}
/**
* Calculates the statistics required for a {@link BoxAndWhiskerItem}
* from a list of <code>Number</code> objects. Any items in the list
* that are <code>null</code>, not an instance of <code>Number</code>, or
* equivalent to <code>Double.NaN</code>, will be ignored.
*
* @param values a list of numbers (a <code>null</code> list is not
* permitted).
* @param stripNullAndNaNItems a flag that controls the handling of null
* and NaN items.
*
* @return A box-and-whisker item.
*
* @since 1.0.3
*/
public static BoxAndWhiskerItem calculateBoxAndWhiskerStatistics(
List<Number> values, boolean stripNullAndNaNItems) {
if (values == null) {
throw new IllegalArgumentException("Null 'values' argument.");
}
List<Number> vlist;
if (stripNullAndNaNItems) {
vlist = new ArrayList<Number>(values.size());
for (Number n : values) {
double v = n.doubleValue();
if (!Double.isNaN(v)) {
vlist.add(n);
}
}
}
else {
vlist = values;
}
Collections.sort(vlist, new NumberComparator());
double mean = Statistics.calculateMean(vlist, false);
double median = Statistics.calculateMedian(vlist, false);
double q1 = calculateQ1(vlist);
double q3 = calculateQ3(vlist);
double interQuartileRange = q3 - q1;
double upperOutlierThreshold = q3 + (interQuartileRange * 1.5);
double lowerOutlierThreshold = q1 - (interQuartileRange * 1.5);
double upperFaroutThreshold = q3 + (interQuartileRange * 2.0);
double lowerFaroutThreshold = q1 - (interQuartileRange * 2.0);
double minRegularValue = Double.POSITIVE_INFINITY;
double maxRegularValue = Double.NEGATIVE_INFINITY;
double minOutlier = Double.POSITIVE_INFINITY;
double maxOutlier = Double.NEGATIVE_INFINITY;
List<Number> outliers = new ArrayList<Number>();
for (Number number : vlist) {
double value = number.doubleValue();
if (value > upperOutlierThreshold) {
outliers.add(number);
if (value > maxOutlier && value <= upperFaroutThreshold) {
maxOutlier = value;
}
} else if (value < lowerOutlierThreshold) {
outliers.add(number);
if (value < minOutlier && value >= lowerFaroutThreshold) {
minOutlier = value;
}
} else {
minRegularValue = Math.min(minRegularValue, value);
maxRegularValue = Math.max(maxRegularValue, value);
}
minOutlier = Math.min(minOutlier, minRegularValue);
maxOutlier = Math.max(maxOutlier, maxRegularValue);
}
return new BoxAndWhiskerItem(mean, median,
q1, q3, minRegularValue,
maxRegularValue, minOutlier,
maxOutlier, outliers);
}
/**
* Calculates the first quartile for a list of numbers in ascending order.
* If the items in the list are not in ascending order, the result is
* unspecified. If the list contains items that are <code>null</code>, not
* an instance of <code>Number</code>, or equivalent to
* <code>Double.NaN</code>, the result is unspecified.
*
* @param values the numbers in ascending order (<code>null</code> not
* permitted).
*
* @return The first quartile.
*/
public static double calculateQ1(List<Number> values) {
if (values == null) {
throw new IllegalArgumentException("Null 'values' argument.");
}
double result = Double.NaN;
int count = values.size();
if (count > 0) {
if (count % 2 == 1) {
if (count > 1) {
result = Statistics.calculateMedian(values, 0, count / 2);
}
else {
result = Statistics.calculateMedian(values, 0, 0);
}
}
else {
result = Statistics.calculateMedian(values, 0, count / 2 - 1);
}
}
return result;
}
/**
* Calculates the third quartile for a list of numbers in ascending order.
* If the items in the list are not in ascending order, the result is
* unspecified. If the list contains items that are <code>null</code>, not
* an instance of <code>Number</code>, or equivalent to
* <code>Double.NaN</code>, the result is unspecified.
*
* @param values the list of values (<code>null</code> not permitted).
*
* @return The third quartile.
*/
public static double calculateQ3(List<Number> values) {
if (values == null) {
throw new IllegalArgumentException("Null 'values' argument.");
}
double result = Double.NaN;
int count = values.size();
if (count > 0) {
if (count % 2 == 1) {
if (count > 1) {
result = Statistics.calculateMedian(values, count / 2,
count - 1);
}
else {
result = Statistics.calculateMedian(values, 0, 0);
}
}
else {
result = Statistics.calculateMedian(values, count / 2,
count - 1);
}
}
return result;
}
}