Mahout itemsimilarity error

[Sameer Tilak <ss...@live.com>]

Hi All,I am running the following command to process a quite large dataset. I want to mention upfront that my input file does contain few blank lines. Any thought on why this might be happening?
./mahout itemsimilarity -i /scratch/SimilartyInput -o /scratch/SimilartyOutput -s SIMILARITY_COOCCURRENCE maxSimilaritiesPerItem 10
13/12/27 11:06:35 INFO common.AbstractJob: Command line arguments: {--booleanData=[false], --endPhase=[2147483647], --input=[/scratch/SimilartyInput], --maxPrefs=[500], --maxSimilaritiesPerItem=[10], --minPrefsPerUser=[1], --output=[/scratch/SimilartyOutput], --similarityClassname=[SIMILARITY_COOCCURRENCE], --startPhase=[0], --tempDir=[temp]}13/12/27 11:06:35 INFO common.AbstractJob: Command line arguments: {--booleanData=[false], --endPhase=[2147483647], --input=[/scratch/SimilartyInput], --minPrefsPerUser=[1], --output=[temp/prepareRatingMatrix], --ratingShift=[0.0], --startPhase=[0], --tempDir=[temp]}13/12/27 11:06:36 INFO input.FileInputFormat: Total input paths to process : 4013/12/27 11:06:36 INFO util.NativeCodeLoader: Loaded the native-hadoop library13/12/27 11:06:36 WARN snappy.LoadSnappy: Snappy native library not loaded13/12/27 11:06:36 INFO mapred.JobClient: Running job: job_201311111627_042313/12/27 11:06:37 INFO mapred.JobClient:  map 0% reduce 0%13/12/27 11:06:52 INFO mapred.JobClient: Task Id : attempt_201311111627_0423_m_000000_0, Status : FAILEDjava.lang.ArrayIndexOutOfBoundsException: 1	at org.apache.mahout.cf.taste.hadoop.item.ItemIDIndexMapper.map(ItemIDIndexMapper.java:50)	at org.apache.mahout.cf.taste.hadoop.item.ItemIDIndexMapper.map(ItemIDIndexMapper.java:31)	at org.apache.hadoop.mapreduce.Mapper.run(Mapper.java:144)	at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:764)	at org.apache.hadoop.mapred.MapTask.run(MapTask.java:370)	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:415)	at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1121)	at org.apache.hadoop.mapred.Child.main(Child.java:249)
13/12/27 11:06:52 INFO mapred.JobClient: Task Id : attempt_201311111627_0423_m_000001_0, Status : FAILEDjava.lang.ArrayIndexOutOfBoundsException: 1	at org.apache.mahout.cf.taste.hadoop.item.ItemIDIndexMapper.map(ItemIDIndexMapper.java:50)	at org.apache.mahout.cf.taste.hadoop.item.ItemIDIndexMapper.map(ItemIDIndexMapper.java:31)	at org.apache.hadoop.mapreduce.Mapper.run(Mapper.java:144)	at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:764)	at org.apache.hadoop.mapred.MapTask.run(MapTask.java:370)	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:415)	at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1121)	at org.apache.hadoop.mapred.Child.main(Child.java:249)
13/12/27 11:06:53 INFO mapred.JobClient: Task Id : attempt_201311111627_0423_m_000002_0, Status : FAILEDjava.lang.ArrayIndexOutOfBoundsException: 1	at org.apache.mahout.cf.taste.hadoop.item.ItemIDIndexMapper.map(ItemIDIndexMapper.java:50)	at org.apache.mahout.cf.taste.hadoop.item.ItemIDIndexMapper.map(ItemIDIndexMapper.java:31)	at org.apache.hadoop.mapreduce.Mapper.run(Mapper.java:144)	at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:764)	at org.apache.hadoop.mapred.MapTask.run(MapTask.java:370)	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:415)	at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1121)	at org.apache.hadoop.mapred.Child.main(Child.java:249)