thanks for your reply Phil. As requested, I opened a Bug in JIRA. (Please give me a hint if I messed anything up)
Anyone knows a possible quick-fix or workaround on the issue? On Wed, 2008-09-24 at 21:37 -0400, Phil Steitz wrote: > This looks like a bug. At least it is a documentation bug. Can you pls > open a JIRA ticket so we do not lose track of it. Follow the > instructions here > http://commons.apache.org/math/issue-tracking.html > Thanks for reporting this. > > Phil > > > Jörg Henning wrote: > > Hello, > > > > I'm relatively new to this kind of stuff, so pardon me, if I get some > > things wrong. > > > > We are using the FDistributionImpl from the commons.math project to do > > some statistical calculations, namely receiving the upper and lower > > boundaries of a confidence interval. Everything is working fine and the > > results are matching our reference calculations. > > > > However, the FDistribution behaves strange if a > > denominatorDegreeOfFreedom of 2 is used, with an alpha-value of 0.95. > > This results in an IllegalArgumentsException, stating: > > > > Invalid endpoint parameters: lowerBound=0.0 initial=Infinity > > upperBound=1.7976931348623157E308 > > > > coming from > > org.apache.commons.math.analysis.UnivariateRealSolverUtils.bracket > > > > The problem is the 'initial' parameter to that function, wich is > > POSITIVE_INFINITY and therefore not within the boundaries. I already > > pinned down the problem to the FDistributions getInitialDomain()-method, > > wich goes like: > > > > return getDenominatorDegreesOfFreedom() / > > (getDenominatorDegreesOfFreedom() - 2.0); > > > > Obviously, in case of denominatorDegreesOfFreedom == 2, this must lead > > to a division-by-zero, resulting in POSTIVE_INFINITY. The result of this > > operation is then directly passed into the > > UnivariateRealSolverUtils.bracket() - method as second argument. > > > > > > Can someone explain what this behaviour is about? Why should a > > degreeOfFreedom of 2 not be allowed? Shouldn't this fact be mentioned in > > the API-documentation? Is there a possible workaround? > > > > Thanks in advance, > > > > > > joerx > > > > > > > > --------------------------------------------------------------------- > > To unsubscribe, e-mail: [EMAIL PROTECTED] > > For additional commands, e-mail: [EMAIL PROTECTED] > > > > > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: [EMAIL PROTECTED] > For additional commands, e-mail: [EMAIL PROTECTED] > Jörg Henning Teamleiter SpectosSolutions -- Spectos GmbH Theaterstrasse 6 01067 Dresden Fon: +49 351 89 66 34 10 Fax: +49 351 46 56 10 42 Mobil: +49 163 444 17 37 Web: www.spectos.com Spectos GmbH Firmensitz: Theaterstrasse 6, 01067 Dresden Registergericht: Amtsgericht Dresden HRB 24787 Geschäftsführer: Niels Delater Diese E-Mail und ihre eventuell beigefügten Anhänge enthalten vertrauliche Informationen, die rechtlich besonders geschützt sein können, z.B. durch die Berufspflichten des Steuerberaters. Diese Informationen sind ausschließlich für die als Adressaten genannten Personen bestimmt. Wenn Sie nicht der angeschriebene Empfänger sind und diese E-Mail durch einen Übertragungsfehler erhalten haben, informieren Sie uns bitte sofort per E-Mail, Telefon oder Fax und löschen Sie danach vorliegende E-Mail. Das unbefugte Kopieren dieser E-Mail, ihrer eventuell beigefügten Anhänge sowie die unbefugte Weitergabe der enthaltenen Informationen an Dritte ist nicht gestattet. Wir danken für Ihre Hilfe. This e-mail message together with its attachments, if any, is confidential and may contain information subject to legal privilege, e.g. to professional obligations of tax advisors. The information contained in this e-mail or its attachments is intended solely for the persons named as addressees. If you are not the intended recipient or have received this e-mail in error, please advise us immediately by e-mail, telephone or fax and delete this message. Any unauthorized copying of this message or unauthorized distribution of the information contained herein is prohibited. Thank you for your co-operation. --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
