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Posted to user@mahout.apache.org by msf <ms...@kisoku.net> on 2010/08/27 11:37:07 UTC

NullPointerException when using bayes.TestClassifier

Hi everyone, 

I've been attempting to use TestClassifier on a directory of roughly
49,000 small text files. When running the following command I receive a
NullPointerException in ConfusionMatrix.getCount(). I've attached the
full verbose output of the mahout run plus the stacktrace. 

This is on 0.4-SNAPSHOT running today's HEAD plus the small patch to
BayesFileFormatter I submitted in MAHOUT-488.

Any pointers on how to go about resolving this problem ?

Thanks, 

-- 
Mathieu Sauve-Frankel

Re: NullPointerException when using bayes.TestClassifier

Posted by msf <ms...@kisoku.net>.
On Fri, Aug 27, 2010 at 06:37:07PM +0900, msf wrote:
> Hi everyone, 
> 
> I've been attempting to use TestClassifier on a directory of roughly
> 49,000 small text files. When running the following command I receive a
> NullPointerException in ConfusionMatrix.getCount(). I've attached the
> full verbose output of the mahout run plus the stacktrace. 
> 
> This is on 0.4-SNAPSHOT running today's HEAD plus the small patch to
> BayesFileFormatter I submitted in MAHOUT-488.
> 
> Any pointers on how to go about resolving this problem ?
> 
> Thanks, 
> 
> -- 
> Mathieu Sauve-Frankel

A little further testing shows that this only gets triggered when trying to
process a directory at a time, TestClassifier seems to work fine when
run against a single file at a time.

Re: NullPointerException when using bayes.TestClassifier

Posted by msf <ms...@kisoku.net>.
On Thu, Sep 16, 2010 at 11:33:48AM +0000, somnath wrote:
> msf <msf <at> kisoku.net> writes:
> 
> > 
> > Hi everyone, 
> > 
> > I've been attempting to use TestClassifier on a directory of roughly
> > 49,000 small text files. When running the following command I receive a
> > NullPointerException in ConfusionMatrix.getCount(). I've attached the
> > full verbose output of the mahout run plus the stacktrace. 
> > 
> > This is on 0.4-SNAPSHOT running today's HEAD plus the small patch to
> > BayesFileFormatter I submitted in MAHOUT-488.
> > 
> > Any pointers on how to go about resolving this problem ?
> > 
> > Thanks, 
> > 
> 
> 
> Hi , 
> please check labels of test data. labels of test data and train data should be 
> same for classifier

Hi, 

I did eventually figure out what I was doing wrong with the classifier,
I had not been converting my test data to the same format used to create
the model. I eventually figured it out by running the newsgroups example code and
looking at the example source files to see exactly what was being done
to prepare the data. The current documentation for testclassifier is not
clear enough in my opinion.

I'll look into what I can do to improve the doco.

Thanks, 

-- 
Mathieu Sauve-Frankel

Re: NullPointerException when using bayes.TestClassifier

Posted by somnath <so...@hotmail.com>.
msf <msf <at> kisoku.net> writes:

> 
> Hi everyone, 
> 
> I've been attempting to use TestClassifier on a directory of roughly
> 49,000 small text files. When running the following command I receive a
> NullPointerException in ConfusionMatrix.getCount(). I've attached the
> full verbose output of the mahout run plus the stacktrace. 
> 
> This is on 0.4-SNAPSHOT running today's HEAD plus the small patch to
> BayesFileFormatter I submitted in MAHOUT-488.
> 
> Any pointers on how to go about resolving this problem ?
> 
> Thanks, 
> 


Hi , 
please check labels of test data. labels of test data and train data should be 
same for classifier