Source Code Cross Referenced for Statistics.java in  » Chart » jfreechart » org » jfree » data » statistics » Java Source Code / Java DocumentationJava Source Code and Java Documentation

Java Source Code / Java Documentation
1. 6.0 JDK Core
2. 6.0 JDK Modules
3. 6.0 JDK Modules com.sun
4. 6.0 JDK Modules com.sun.java
5. 6.0 JDK Modules sun
6. 6.0 JDK Platform
7. Ajax
8. Apache Harmony Java SE
9. Aspect oriented
10. Authentication Authorization
11. Blogger System
12. Build
13. Byte Code
14. Cache
15. Chart
16. Chat
17. Code Analyzer
18. Collaboration
19. Content Management System
20. Database Client
21. Database DBMS
22. Database JDBC Connection Pool
23. Database ORM
24. Development
25. EJB Server geronimo
26. EJB Server GlassFish
27. EJB Server JBoss 4.2.1
28. EJB Server resin 3.1.5
29. ERP CRM Financial
30. ESB
31. Forum
32. GIS
33. Graphic Library
34. Groupware
35. HTML Parser
36. IDE
37. IDE Eclipse
38. IDE Netbeans
39. Installer
40. Internationalization Localization
41. Inversion of Control
42. Issue Tracking
43. J2EE
44. JBoss
45. JMS
46. JMX
47. Library
48. Mail Clients
49. Net
50. Parser
51. PDF
52. Portal
53. Profiler
54. Project Management
55. Report
56. RSS RDF
57. Rule Engine
58. Science
59. Scripting
60. Search Engine
61. Security
62. Sevlet Container
63. Source Control
64. Swing Library
65. Template Engine
66. Test Coverage
67. Testing
68. UML
69. Web Crawler
70. Web Framework
71. Web Mail
72. Web Server
73. Web Services
74. Web Services apache cxf 2.0.1
75. Web Services AXIS2
76. Wiki Engine
77. Workflow Engines
78. XML
79. XML UI
Java
Java Tutorial
Java Open Source
Jar File Download
Java Articles
Java Products
Java by API
Photoshop Tutorials
Maya Tutorials
Flash Tutorials
3ds-Max Tutorials
Illustrator Tutorials
GIMP Tutorials
C# / C Sharp
C# / CSharp Tutorial
C# / CSharp Open Source
ASP.Net
ASP.NET Tutorial
JavaScript DHTML
JavaScript Tutorial
JavaScript Reference
HTML / CSS
HTML CSS Reference
C / ANSI-C
C Tutorial
C++
C++ Tutorial
Ruby
PHP
Python
Python Tutorial
Python Open Source
SQL Server / T-SQL
SQL Server / T-SQL Tutorial
Oracle PL / SQL
Oracle PL/SQL Tutorial
PostgreSQL
SQL / MySQL
MySQL Tutorial
VB.Net
VB.Net Tutorial
Flash / Flex / ActionScript
VBA / Excel / Access / Word
XML
XML Tutorial
Microsoft Office PowerPoint 2007 Tutorial
Microsoft Office Excel 2007 Tutorial
Microsoft Office Word 2007 Tutorial
Java Source Code / Java Documentation » Chart » jfreechart » org.jfree.data.statistics 
Source Cross Referenced  Class Diagram Java Document (Java Doc) 


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:         * Statistics.java
029:         * ---------------
030:         * (C) Copyright 2000-2006, by Matthew Wright and Contributors.
031:         *
032:         * Original Author:  Matthew Wright;
033:         * Contributor(s):   David Gilbert (for Object Refinery Limited);
034:         *
035:         * $Id: Statistics.java,v 1.5.2.2 2006/11/16 11:19:47 mungady Exp $
036:         *
037:         * Changes (from 08-Nov-2001)
038:         * --------------------------
039:         * 08-Nov-2001 : Added standard header and tidied Javadoc comments (DG);
040:         *               Moved from JFreeChart to package com.jrefinery.data.* in 
041:         *               JCommon class library (DG);
042:         * 24-Jun-2002 : Removed unnecessary local variable (DG);
043:         * 07-Oct-2002 : Fixed errors reported by Checkstyle (DG);
044:         * 26-May-2004 : Moved calculateMean() method from BoxAndWhiskerCalculator (DG);
045:         * 02-Jun-2004 : Fixed bug in calculateMedian() method (DG);
046:         * 11-Jan-2005 : Removed deprecated code in preparation for the 1.0.0 
047:         *               release (DG);
048:         *
049:         */
050:
051:        package org.jfree.data.statistics;
052:
053:        import java.util.ArrayList;
054:        import java.util.Collection;
055:        import java.util.Collections;
056:        import java.util.Iterator;
057:        import java.util.List;
058:
059:        /**
060:         * A utility class that provides some common statistical functions.
061:         */
062:        public abstract class Statistics {
063:
064:            /**
065:             * Returns the mean of an array of numbers.  This is equivalent to calling
066:             * <code>calculateMean(values, true)</code>.
067:             *
068:             * @param values  the values (<code>null</code> not permitted).
069:             *
070:             * @return The mean.
071:             */
072:            public static double calculateMean(Number[] values) {
073:                return calculateMean(values, true);
074:            }
075:
076:            /**
077:             * Returns the mean of an array of numbers.
078:             *
079:             * @param values  the values (<code>null</code> not permitted).
080:             * @param includeNullAndNaN  a flag that controls whether or not 
081:             *     <code>null</code> and <code>Double.NaN</code> values are included
082:             *     in the calculation (if either is present in the array, the result is 
083:             *     {@link Double#NaN}).
084:             *
085:             * @return The mean.
086:             * 
087:             * @since 1.0.3
088:             */
089:            public static double calculateMean(Number[] values,
090:                    boolean includeNullAndNaN) {
091:
092:                if (values == null) {
093:                    throw new IllegalArgumentException(
094:                            "Null 'values' argument.");
095:                }
096:                double sum = 0.0;
097:                double current;
098:                int counter = 0;
099:                for (int i = 0; i < values.length; i++) {
100:                    // treat nulls the same as NaNs
101:                    if (values[i] != null) {
102:                        current = values[i].doubleValue();
103:                    } else {
104:                        current = Double.NaN;
105:                    }
106:                    // calculate the sum and count
107:                    if (includeNullAndNaN || !Double.isNaN(current)) {
108:                        sum = sum + current;
109:                        counter++;
110:                    }
111:                }
112:                double result = (sum / counter);
113:                return result;
114:            }
115:
116:            /**
117:             * Returns the mean of a collection of <code>Number</code> objects.
118:             * 
119:             * @param values  the values (<code>null</code> not permitted).
120:             * 
121:             * @return The mean.
122:             */
123:            public static double calculateMean(Collection values) {
124:                return calculateMean(values, true);
125:            }
126:
127:            /**
128:             * Returns the mean of a collection of <code>Number</code> objects.
129:             * 
130:             * @param values  the values (<code>null</code> not permitted).
131:             * @param includeNullAndNaN  a flag that controls whether or not 
132:             *     <code>null</code> and <code>Double.NaN</code> values are included
133:             *     in the calculation (if either is present in the array, the result is 
134:             *     {@link Double#NaN}).
135:             * 
136:             * @return The mean.
137:             * 
138:             * @since 1.0.3
139:             */
140:            public static double calculateMean(Collection values,
141:                    boolean includeNullAndNaN) {
142:
143:                if (values == null) {
144:                    throw new IllegalArgumentException(
145:                            "Null 'values' argument.");
146:                }
147:                int count = 0;
148:                double total = 0.0;
149:                Iterator iterator = values.iterator();
150:                while (iterator.hasNext()) {
151:                    Object object = iterator.next();
152:                    if (object == null) {
153:                        if (includeNullAndNaN) {
154:                            return Double.NaN;
155:                        }
156:                    } else {
157:                        if (object instanceof  Number) {
158:                            Number number = (Number) object;
159:                            double value = number.doubleValue();
160:                            if (Double.isNaN(value)) {
161:                                if (includeNullAndNaN) {
162:                                    return Double.NaN;
163:                                }
164:                            } else {
165:                                total = total + number.doubleValue();
166:                                count = count + 1;
167:                            }
168:                        }
169:                    }
170:                }
171:                return total / count;
172:            }
173:
174:            /**
175:             * Calculates the median for a list of values (<code>Number</code> objects).
176:             * The list of values will be copied, and the copy sorted, before 
177:             * calculating the median.  To avoid this step (if your list of values
178:             * is already sorted), use the {@link #calculateMedian(List, boolean)} 
179:             * method.
180:             * 
181:             * @param values  the values (<code>null</code> permitted).
182:             * 
183:             * @return The median.
184:             */
185:            public static double calculateMedian(List values) {
186:                return calculateMedian(values, true);
187:            }
188:
189:            /**
190:             * Calculates the median for a list of values (<code>Number</code> objects).
191:             * If <code>copyAndSort</code> is <code>false</code>, the list is assumed
192:             * to be presorted in ascending order by value.
193:             * 
194:             * @param values  the values (<code>null</code> permitted).
195:             * @param copyAndSort  a flag that controls whether the list of values is
196:             *                     copied and sorted.
197:             * 
198:             * @return The median.
199:             */
200:            public static double calculateMedian(List values,
201:                    boolean copyAndSort) {
202:
203:                double result = Double.NaN;
204:                if (values != null) {
205:                    if (copyAndSort) {
206:                        int itemCount = values.size();
207:                        List copy = new ArrayList(itemCount);
208:                        for (int i = 0; i < itemCount; i++) {
209:                            copy.add(i, values.get(i));
210:                        }
211:                        Collections.sort(copy);
212:                        values = copy;
213:                    }
214:                    int count = values.size();
215:                    if (count > 0) {
216:                        if (count % 2 == 1) {
217:                            if (count > 1) {
218:                                Number value = (Number) values
219:                                        .get((count - 1) / 2);
220:                                result = value.doubleValue();
221:                            } else {
222:                                Number value = (Number) values.get(0);
223:                                result = value.doubleValue();
224:                            }
225:                        } else {
226:                            Number value1 = (Number) values.get(count / 2 - 1);
227:                            Number value2 = (Number) values.get(count / 2);
228:                            result = (value1.doubleValue() + value2
229:                                    .doubleValue()) / 2.0;
230:                        }
231:                    }
232:                }
233:                return result;
234:            }
235:
236:            /**
237:             * Calculates the median for a sublist within a list of values 
238:             * (<code>Number</code> objects).
239:             * 
240:             * @param values  the values, in any order (<code>null</code> not 
241:             *                permitted).
242:             * @param start  the start index.
243:             * @param end  the end index.
244:             * 
245:             * @return The median.
246:             */
247:            public static double calculateMedian(List values, int start, int end) {
248:                return calculateMedian(values, start, end, true);
249:            }
250:
251:            /**
252:             * Calculates the median for a sublist within a list of values 
253:             * (<code>Number</code> objects).  The entire list will be sorted if the 
254:             * <code>ascending</code< argument is <code>false</code>.
255:             * 
256:             * @param values  the values (<code>null</code> not permitted).
257:             * @param start  the start index.
258:             * @param end  the end index.
259:             * @param copyAndSort  a flag that that controls whether the list of values 
260:             *                     is copied and sorted.
261:             * 
262:             * @return The median.
263:             */
264:            public static double calculateMedian(List values, int start,
265:                    int end, boolean copyAndSort) {
266:
267:                double result = Double.NaN;
268:                if (copyAndSort) {
269:                    List working = new ArrayList(end - start + 1);
270:                    for (int i = start; i <= end; i++) {
271:                        working.add(values.get(i));
272:                    }
273:                    Collections.sort(working);
274:                    result = calculateMedian(working, false);
275:                } else {
276:                    int count = end - start + 1;
277:                    if (count > 0) {
278:                        if (count % 2 == 1) {
279:                            if (count > 1) {
280:                                Number value = (Number) values.get(start
281:                                        + (count - 1) / 2);
282:                                result = value.doubleValue();
283:                            } else {
284:                                Number value = (Number) values.get(start);
285:                                result = value.doubleValue();
286:                            }
287:                        } else {
288:                            Number value1 = (Number) values.get(start + count
289:                                    / 2 - 1);
290:                            Number value2 = (Number) values.get(start + count
291:                                    / 2);
292:                            result = (value1.doubleValue() + value2
293:                                    .doubleValue()) / 2.0;
294:                        }
295:                    }
296:                }
297:                return result;
298:
299:            }
300:
301:            /**
302:             * Returns the standard deviation of a set of numbers.
303:             *
304:             * @param data  the data (<code>null</code> or zero length array not 
305:             *     permitted).
306:             *
307:             * @return The standard deviation of a set of numbers.
308:             */
309:            public static double getStdDev(Number[] data) {
310:                if (data == null) {
311:                    throw new IllegalArgumentException("Null 'data' array.");
312:                }
313:                if (data.length == 0) {
314:                    throw new IllegalArgumentException(
315:                            "Zero length 'data' array.");
316:                }
317:                double avg = calculateMean(data);
318:                double sum = 0.0;
319:
320:                for (int counter = 0; counter < data.length; counter++) {
321:                    double diff = data[counter].doubleValue() - avg;
322:                    sum = sum + diff * diff;
323:                }
324:                return Math.sqrt(sum / (data.length - 1));
325:            }
326:
327:            /**
328:             * Fits a straight line to a set of (x, y) data, returning the slope and
329:             * intercept.
330:             *
331:             * @param xData  the x-data (<code>null</code> not permitted).
332:             * @param yData  the y-data (<code>null</code> not permitted).
333:             *
334:             * @return A double array with the intercept in [0] and the slope in [1].
335:             */
336:            public static double[] getLinearFit(Number[] xData, Number[] yData) {
337:
338:                if (xData == null) {
339:                    throw new IllegalArgumentException("Null 'xData' argument.");
340:                }
341:                if (yData == null) {
342:                    throw new IllegalArgumentException("Null 'yData' argument.");
343:                }
344:                if (xData.length != yData.length) {
345:                    throw new IllegalArgumentException(
346:                            "Statistics.getLinearFit(): array lengths must be equal.");
347:                }
348:
349:                double[] result = new double[2];
350:                // slope
351:                result[1] = getSlope(xData, yData);
352:                // intercept
353:                result[0] = calculateMean(yData) - result[1]
354:                        * calculateMean(xData);
355:
356:                return result;
357:
358:            }
359:
360:            /**
361:             * Finds the slope of a regression line using least squares.
362:             *
363:             * @param xData  the x-values (<code>null</code> not permitted).
364:             * @param yData  the y-values (<code>null</code> not permitted).
365:             *
366:             * @return The slope.
367:             */
368:            public static double getSlope(Number[] xData, Number[] yData) {
369:
370:                if (xData == null) {
371:                    throw new IllegalArgumentException("Null 'xData' argument.");
372:                }
373:                if (yData == null) {
374:                    throw new IllegalArgumentException("Null 'yData' argument.");
375:                }
376:                if (xData.length != yData.length) {
377:                    throw new IllegalArgumentException(
378:                            "Array lengths must be equal.");
379:                }
380:
381:                // ********* stat function for linear slope ********
382:                // y = a + bx
383:                // a = ybar - b * xbar
384:                //     sum(x * y) - (sum (x) * sum(y)) / n
385:                // b = ------------------------------------
386:                //     sum (x^2) - (sum(x)^2 / n
387:                // *************************************************
388:
389:                // sum of x, x^2, x * y, y
390:                double sx = 0.0, sxx = 0.0, sxy = 0.0, sy = 0.0;
391:                int counter;
392:                for (counter = 0; counter < xData.length; counter++) {
393:                    sx = sx + xData[counter].doubleValue();
394:                    sxx = sxx + Math.pow(xData[counter].doubleValue(), 2);
395:                    sxy = sxy + yData[counter].doubleValue()
396:                            * xData[counter].doubleValue();
397:                    sy = sy + yData[counter].doubleValue();
398:                }
399:                return (sxy - (sx * sy) / counter)
400:                        / (sxx - (sx * sx) / counter);
401:
402:            }
403:
404:            /**
405:             * Calculates the correlation between two datasets.  Both arrays should 
406:             * contain the same number of items.  Null values are treated as zero.
407:             * <P>
408:             * Information about the correlation calculation was obtained from:
409:             * 
410:             * http://trochim.human.cornell.edu/kb/statcorr.htm
411:             * 
412:             * @param data1  the first dataset.
413:             * @param data2  the second dataset.
414:             * 
415:             * @return The correlation.
416:             */
417:            public static double getCorrelation(Number[] data1, Number[] data2) {
418:                if (data1 == null) {
419:                    throw new IllegalArgumentException("Null 'data1' argument.");
420:                }
421:                if (data2 == null) {
422:                    throw new IllegalArgumentException("Null 'data2' argument.");
423:                }
424:                if (data1.length != data2.length) {
425:                    throw new IllegalArgumentException(
426:                            "'data1' and 'data2' arrays must have same length.");
427:                }
428:                int n = data1.length;
429:                double sumX = 0.0;
430:                double sumY = 0.0;
431:                double sumX2 = 0.0;
432:                double sumY2 = 0.0;
433:                double sumXY = 0.0;
434:                for (int i = 0; i < n; i++) {
435:                    double x = 0.0;
436:                    if (data1[i] != null) {
437:                        x = data1[i].doubleValue();
438:                    }
439:                    double y = 0.0;
440:                    if (data2[i] != null) {
441:                        y = data2[i].doubleValue();
442:                    }
443:                    sumX = sumX + x;
444:                    sumY = sumY + y;
445:                    sumXY = sumXY + (x * y);
446:                    sumX2 = sumX2 + (x * x);
447:                    sumY2 = sumY2 + (y * y);
448:                }
449:                return (n * sumXY - sumX * sumY)
450:                        / Math.pow((n * sumX2 - sumX * sumX)
451:                                * (n * sumY2 - sumY * sumY), 0.5);
452:            }
453:
454:            /**
455:             * Returns a data set for a moving average on the data set passed in.
456:             *
457:             * @param xData  an array of the x data.
458:             * @param yData  an array of the y data.
459:             * @param period  the number of data points to average
460:             *
461:             * @return A double[][] the length of the data set in the first dimension,
462:             *         with two doubles for x and y in the second dimension
463:             */
464:            public static double[][] getMovingAverage(Number[] xData,
465:                    Number[] yData, int period) {
466:
467:                // check arguments...
468:                if (xData.length != yData.length) {
469:                    throw new IllegalArgumentException(
470:                            "Array lengths must be equal.");
471:                }
472:
473:                if (period > xData.length) {
474:                    throw new IllegalArgumentException(
475:                            "Period can't be longer than dataset.");
476:                }
477:
478:                double[][] result = new double[xData.length - period][2];
479:                for (int i = 0; i < result.length; i++) {
480:                    result[i][0] = xData[i + period].doubleValue();
481:                    // holds the moving average sum
482:                    double sum = 0.0;
483:                    for (int j = 0; j < period; j++) {
484:                        sum += yData[i + j].doubleValue();
485:                    }
486:                    sum = sum / period;
487:                    result[i][1] = sum;
488:                }
489:                return result;
490:
491:            }
492:
493:        }
www.java2java.com | Contact Us
Copyright 2009 - 12 Demo Source and Support. All rights reserved.
All other trademarks are property of their respective owners.