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From Brian Arnold <barnold4...@gmail.com>
Subject Issue with ParallelALSFactorizationJob
Date Thu, 24 Oct 2013 03:03:51 GMT
Hey Everyone,

I was just trying to run the ParallelALSFactorizedJob on my Hadoop cluster
and my job failed severals jobs in with the following error below.  The
name of the failed job was (Recompute U, iteration (2/10), (1 threads, 20
features, implicit feedback)).  Does anyone have any idea of what may be
causing this? Here is a few lines from my input file as well:

120625006,896538,12.0
121573206,896538,20.0
121587646,896538,14.0


2013-10-23 21:21:10,806 WARN org.apache.hadoop.mapred.Child: Error running
child

java.lang.RuntimeException: java.lang.NullPointerException
	at org.apache.hadoop.mapreduce.lib.map.MultithreadedMapper.run(MultithreadedMapper.java:149)
	at org.apache.mahout.cf.taste.hadoop.als.MultithreadedSharingMapper.run(MultithreadedSharingMapper.java:53)
	at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:763)
	at org.apache.hadoop.mapred.MapTask.run(MapTask.java:363)
	at org.apache.hadoop.mapred.Child$4.run(Child.java:255)
	at java.security.AccessController.doPrivileged(Native Method)
	at javax.security.auth.Subject.doAs(Subject.java:396)
	at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1232)
	at org.apache.hadoop.mapred.Child.main(Child.java:249)
Caused by: java.lang.NullPointerException
	at org.apache.mahout.math.als.ImplicitFeedbackAlternatingLeastSquaresSolver.getYtransponseCuMinusIYPlusLambdaI(ImplicitFeedbackAlternatingLeastSquaresSolver.java:95)
	at org.apache.mahout.math.als.ImplicitFeedbackAlternatingLeastSquaresSolver.solve(ImplicitFeedbackAlternatingLeastSquaresSolver.java:51)
	at org.apache.mahout.cf.taste.hadoop.als.SolveImplicitFeedbackMapper.map(SolveImplicitFeedbackMapper.java:54)
	at org.apache.mahout.cf.taste.hadoop.als.SolveImplicitFeedbackMapper.map(SolveImplicitFeedbackMapper.java:29)
	at org.apache.hadoop.mapreduce.Mapper.run(Mapper.java:145)
	at org.apache.hadoop.mapreduce.lib.map.MultithreadedMapper$MapRunner.run(MultithreadedMapper.java:268)

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