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Posted to dev@mahout.apache.org by "Pat Ferrel (JIRA)" <ji...@apache.org> on 2012/07/14 17:37:34 UTC
[jira] [Comment Edited] (MAHOUT-1045) Cluster evaluators returning
bad results
[ https://issues.apache.org/jira/browse/MAHOUT-1045?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13414431#comment-13414431 ]
Pat Ferrel edited comment on MAHOUT-1045 at 7/14/12 3:36 PM:
-------------------------------------------------------------
I checked the data set linked above by only running the evaluators on it. I got results listed below. The values are almost identical to the first evaluator values I got so we have the right data isolated. I assume the small differences are due to different representative points?
Inter-Cluster Density: 0.9289881620012391
Intra-Cluster Density: NaN
CDbw Inter-Cluster Density: 0.0
CDbw Intra-Cluster Density: 1050.0723680608382
CDbw Separation: 187792.32137017616
I'll start looking at the NaN and 0 values when I get time, no idea if the other values are correct but eliminating the obvious errors seems like a good place to start.
was (Author: pferrel):
I checked the data set linked above by only running the evaluators on it. I got results listed below. They are a fair bit different, I assume because of different representative points? In any case they did result in the problematic the NaN and 0 values.
Inter-Cluster Density: 0.9289881620012391
Intra-Cluster Density: NaN
CDbw Inter-Cluster Density: 0.0
CDbw Intra-Cluster Density: 1050.0723680608382
CDbw Separation: 187792.32137017616
I think I'll try running the RepresentativePointsDriver with a higher maxiter value and see if the results improve (less clusters pruned for instance).
> Cluster evaluators returning bad results
> ----------------------------------------
>
> Key: MAHOUT-1045
> URL: https://issues.apache.org/jira/browse/MAHOUT-1045
> Project: Mahout
> Issue Type: Bug
> Components: Clustering
> Affects Versions: 0.6, 0.7, 0.8
> Environment: Several environments and data sets
> Reporter: Pat Ferrel
> Fix For: 0.8
>
>
> With real world crawl data the Intra-cluster density from ClusterEvaluator is almost always NaN. The CDbw inter-cluster density is almost always 0. I have also seen several cases where CDbw fails to return any results but have not tracked down why yet.
> I have sent a link to an 8G data set that reproduces these errors to Jeff Eastman.
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