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Posted to dev@mahout.apache.org by "Suneel Marthi (JIRA)" <ji...@apache.org> on 2013/11/17 09:49:23 UTC
[jira] [Commented] (MAHOUT-1314) StreamingKMeansReducer throws
NullPointerException when REDUCE_STREAMING_KMEANS is set to true
[ https://issues.apache.org/jira/browse/MAHOUT-1314?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13824777#comment-13824777 ]
Suneel Marthi commented on MAHOUT-1314:
---------------------------------------
I see this issue happen in the present codebase while running this on reuters dataset. Here's the stacktrace:
{Code}
java.lang.NullPointerException
at com.google.common.base.Preconditions.checkNotNull(Preconditions.java:192)
at org.apache.mahout.math.random.WeightedThing.<init>(WeightedThing.java:31)
at org.apache.mahout.math.neighborhood.BruteSearch.searchFirst(BruteSearch.java:127)
at org.apache.mahout.clustering.ClusteringUtils.estimateDistanceCutoff(ClusteringUtils.java:116)
at org.apache.mahout.clustering.streaming.mapreduce.StreamingKMeansThread.call(StreamingKMeansThread.java:63)
at org.apache.mahout.clustering.streaming.mapreduce.StreamingKMeansReducer.reduce(StreamingKMeansReducer.java:55)
at org.apache.mahout.clustering.streaming.mapreduce.StreamingKMeansReducer.reduce(StreamingKMeansReducer.java:35)
at org.apache.hadoop.mapreduce.Reducer.run(Reducer.java:177)
at org.apache.hadoop.mapred.ReduceTask.runNewReducer(ReduceTask.java:649)
at org.apache.hadoop.mapred.ReduceTask.run(ReduceTask.java:418)
at org.apache.hadoop.mapred.LocalJobRunner$Job.run(LocalJobRunner.java:398)
{Code}
> StreamingKMeansReducer throws NullPointerException when REDUCE_STREAMING_KMEANS is set to true
> ----------------------------------------------------------------------------------------------
>
> Key: MAHOUT-1314
> URL: https://issues.apache.org/jira/browse/MAHOUT-1314
> Project: Mahout
> Issue Type: Bug
> Components: Clustering
> Affects Versions: 0.8
> Reporter: Adi Haviv
> Fix For: 0.9
>
>
> when REDUCE_STREAMING_KMEANS option is set to true (-rskm) the reducer fails with NullPointerException.
> the problem is in the reduce method itself: on line 60 ( return input.getCentroid(); )
> it should be input.getCentroid().clone();
> similar to line 81.
> full stack trace:
> java.lang.NullPointerException
> at com.google.common.base.Preconditions.checkNotNull(Preconditions.java:191)
> at org.apache.mahout.math.random.WeightedThing.<init>(WeightedThing.java:31)
> at org.apache.mahout.math.neighborhood.BruteSearch.searchFirst(BruteSearch.java:133)
> at org.apache.mahout.clustering.ClusteringUtils.estimateDistanceCutoff(ClusteringUtils.java:100)
> at org.apache.mahout.clustering.streaming.mapreduce.StreamingKMeansThread.call(StreamingKMeansThread.java:64)
> at org.apache.mahout.clustering.streaming.mapreduce.StreamingKMeansReducer.reduce(StreamingKMeansReducer.java:66)
> at org.apache.mahout.clustering.streaming.mapreduce.StreamingKMeansReducer.reduce(StreamingKMeansReducer.java:1)
> at org.apache.hadoop.mapreduce.Reducer.run(Reducer.java:176)
> at org.apache.hadoop.mapred.ReduceTask.runNewReducer(ReduceTask.java:650)
> at org.apache.hadoop.mapred.ReduceTask.run(ReduceTask.java:418)
> at org.apache.hadoop.mapred.LocalJobRunner$Job.run(LocalJobRunner.java:260)
> it happens every time the REDUCE_STREAMING_KMEANS is set to true.
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