[
https://issues.apache.org/jira/browse/MATH-1315?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15091184#comment-15091184
]
Thomas Neidhart commented on MATH-1315:
---------------------------------------
Indeed, you are right this has to be fixed.
> MultiKMeansPlusPlusClusterer buggy for alternative evaluators
> -------------------------------------------------------------
>
> Key: MATH-1315
> URL: https://issues.apache.org/jira/browse/MATH-1315
> Project: Commons Math
> Issue Type: Bug
> Affects Versions: 3.5
> Reporter: Thorsten Schäfer
>
> I just looked into the source code for the MultiKMeansPlusPlusClusterer and
> realized that it would return null in case of an alternative evaluator that
> favors bigger values instead of smaller ones:
> The basic idea of the clustering method is that we perform n clusterings and
> choose the best result. The decision what's the best result is performed by
> the evaluator, which by default assumes smaller values are better.
> According to the documentation, we can also provide a different evaluator,
> which for instance would decide that bigger values are better, but given we
> initialize the best value with Double.POSITIVE_INFINITY in method
> MultiKMeansPlusPlusClusterer.cluster(Collection<T>), we would never find a
> "better" result and thus always return null.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
