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https://issues.apache.org/jira/browse/MAHOUT-1030?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Jeff Eastman updated MAHOUT-1030:
---------------------------------
Attachment: MAHOUT-1030.patch
This patch modifies the classify() method of AbstractClusteringPolicy to remove
the normalization in order that pdf values in the WeightedVectorWritable can be
back-converted into the original distance measure distance.
Not sure which direction to go on this issue right now. If this fixes the
regression adequately, it introduces another incompatibility with
AbstractVectorClassifier's expectation of normalized results. The downside of
this approach needs to be weighed against the much larger patch needed to
return WeightedPropertyVectorWritables in the first version of the patch.
> Regression: Clustered Points Should be WeightedPropertyVectorWritable not
> WeightedVectorWritable
> ------------------------------------------------------------------------------------------------
>
> Key: MAHOUT-1030
> URL: https://issues.apache.org/jira/browse/MAHOUT-1030
> Project: Mahout
> Issue Type: Bug
> Components: Clustering, Integration
> Affects Versions: 0.7
> Reporter: Jeff Eastman
> Assignee: Jeff Eastman
> Fix For: 0.8
>
> Attachments: MAHOUT-1030.patch, MAHOUT-1030.patch, MAHOUT-1030.patch
>
>
> Looks like this won't make it into this build. Pretty widespread impact on
> code and tests and I don't know which properties were implemented in the old
> version. I will create a JIRA and post my interim results.
> On 6/8/12 12:21 PM, Jeff Eastman wrote:
> > That's a reversion that evidently got in when the new
> > ClusterClassificationDriver was introduced. It should be a pretty easy fix
> > and I will see if I can make the change before Paritosh cuts the release
> > bits tonight.
> >
> > On 6/7/12 1:00 PM, Pat Ferrel wrote:
> >> It appears that in kmeans the clusteredPoints are now written as
> >> WeightedVectorWritable where in mahout 0.6 they were
> >> WeightedPropertyVectorWritable? This means that the distance from the
> >> centroid is no longer stored here? Why? I hope I'm wrong because that is
> >> not a welcome change. How is one to order clustered docs by distance from
> >> cluster centroid?
> >>
> >> I'm sure I could calculate the distance but that would mean looking up the
> >> centroid for the cluster id given in the above WeightedVectorWritable,
> >> which means iterating through all the clusters for each clustered doc. In
> >> my case the number of clusters could be fairly large.
> >>
> >> Am I missing something?
> >>
> >>
> >
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