[
https://issues.apache.org/jira/browse/MAHOUT-1103?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13672658#comment-13672658
]
Grant Ingersoll commented on MAHOUT-1103:
-----------------------------------------
This seems like a flat out bug in the ClusterPP, since it says it is supposed
to write separate directories, so it doesn't seem to me like we need to add new
classes here, but instead should fix the bug. Still looking.
> clusterpp is not writing directories for all clusters
> -----------------------------------------------------
>
> Key: MAHOUT-1103
> URL: https://issues.apache.org/jira/browse/MAHOUT-1103
> Project: Mahout
> Issue Type: Bug
> Components: Clustering
> Affects Versions: 0.8
> Reporter: Matt Molek
> Assignee: Grant Ingersoll
> Labels: clusterpp
> Fix For: 0.8
>
> Attachments: MAHOUT-1103.patch
>
>
> After running kmeans clustering on a set of ~3M points, clusterpp fails to
> populate directories for some clusters, no matter what k is.
> I've tested this on my data with k = 300, 250, 150, 100, 50, 25, 10, 5, 2
> Even with k=2 only one cluster directory was created. For each reducer that
> fails to produce directories there is an empty part-r-* file in the output
> directory.
> Here is my command sequence for the k=2 run:
> {noformat}bin/mahout kmeans -i ssvd2/USigma -c 2clusters/init-clusters -o
> 2clusters/pca-clusters -dm
> org.apache.mahout.common.distance.TanimotoDistanceMeasure -cd 0.05 -k 2 -x 15
> -cl
> bin/mahout clusterdump -i 2clusters/pca-clusters/clusters-*-final -o
> 2clusters.txt
> bin/mahout clusterpp -i 2clusters/pca-clusters -o 2clusters/bottom{noformat}
> The output of clusterdump shows two clusters: VL-3742464 and VL-3742466
> containing 2585843 and 1156624 points respectively.
> Discussion on the user mailing list suggested that this might be caused by
> the default hadoop hash partitioner. The hashes of these two clusters aren't
> identical, but they are close. Putting both cluster names into a Text and
> caling hashCode() gives:
> VL-3742464 -> -685560454
> VL-3742466 -> -685560452
> Finally, when running with "-xm sequential", everything performs as expected.
--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira
