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List:       wekalist
Subject:    Re: [Wekalist] Overflow Error
From:       Eibe Frank <eibe () waikato ! ac ! nz>
Date:       2014-11-27 3:49:42
Message-ID: 98EAAF28-E8CD-471D-BE1A-20BC430969E7 () waikato ! ac ! nz
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Thanks for pointing this out. It should be fixed now in SVN.

Note that you may get unclassified instances when -A 0 because the estimated joint \
probability may be zero for all classes.

Cheers,
Eibe

> On 19 Nov 2014, at 22:15, Oliver Sampson <oliver.sampson@uni-konstanz.de> wrote:
> 
> Hi,
> While getting familiar with Bayesian Nets in Weka, I stumbled on an Overflow error.
> 
> Using the iris.arff file included with the distribution, using the BayesNet \
> classifier, with all standard options (K2, Simple Estimator and so on), except for \
> setting the alpha to 0 as described in "Bayesian Network Classifiers in Weka for \
> Version 3-5-7." 
> http://www.cs.waikato.ac.nz/~remco/weka.bn.pdf
> 
> "With alpha = 0, we get maximum likelihood estimates."
> 
> The result is:
> java.lang.ArithmeticException: lnGamma: Overflow
> weka.core.Statistics.lnGamma(Statistics.java:307)
> weka.classifiers.bayes.net.estimate.DiscreteEstimatorBayes.logScore(DiscreteEstimatorBayes.java:145)
>  weka.classifiers.bayes.net.search.local.LocalScoreSearchAlgorithm.logScore(LocalScoreSearchAlgorithm.java:128)
>  weka.classifiers.bayes.BayesNet.measureBayesScore(BayesNet.java:1061)
> weka.classifiers.bayes.BayesNet.toString(BayesNet.java:709)
> weka.gui.explorer.ClassifierPanel$16.run(ClassifierPanel.java:1443)
> 
> at weka.core.Statistics.lnGamma(Statistics.java:307)
> at weka.classifiers.bayes.net.estimate.DiscreteEstimatorBayes.logScore(DiscreteEstimatorBayes.java:145)
>  at weka.classifiers.bayes.net.search.local.LocalScoreSearchAlgorithm.logScore(LocalScoreSearchAlgorithm.java:128)
>  at weka.classifiers.bayes.BayesNet.measureBayesScore(BayesNet.java:1061)
> at weka.classifiers.bayes.BayesNet.toString(BayesNet.java:709)
> at weka.gui.explorer.ClassifierPanel$16.run(ClassifierPanel.java:1443)
> 
> Hopefully, this can be of some assistance.
> 
> Kind regards,
> -- 
> Oliver Sampson
> oliver.sampson@uni-konstanz.de
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