Exception - java.lang.IllegalArgumentException: Label not found in Mahout - hadoop

Question

I am running the following commands,
/mahout trainnb
-i ${WORK_DIR}/20news-train-vectors -el
-o ${WORK_DIR}/model
-li ${WORK_DIR}/labelindex
-ow
./mahout testnb
-i ${WORK_DIR}/20news-test-vectors
-m ${WORK_DIR}/model
-l ${WORK_DIR}/labelindex\
-ow -o ${WORK_DIR}/20news-testing
On running the last command,I am able to run the map task to 100% but on reduce task I am getting the the following Error:
Exception in thread "main" java.lang.IllegalArgumentException: Label not found: 10002
at com.google.common.base.Preconditions.checkArgument(Preconditions.java:88)
at org.apache.mahout.classifier.ConfusionMatrix.getCount(ConfusionMatrix.java:182)
at org.apache.mahout.classifier.ConfusionMatrix.incrementCount(ConfusionMatrix.java: 205)
at org.apache.mahout.classifier.ConfusionMatrix.incrementCount(ConfusionMatrix.java: 209)
at org.apache.mahout.classifier.ConfusionMatrix.addInstance(ConfusionMatrix.java:173 )
at org.apache.mahout.classifier.ResultAnalyzer.addInstance(ResultAnalyzer.java:70)
at org.apache.mahout.classifier.naivebayes.test.TestNaiveBayesDriver.analyzeResults( TestNaiveBayesDriver.java:160)
at org.apache.mahout.classifier.naivebayes.test.TestNaiveBayesDriver.run(TestNaiveBa yesDriver.java:125)
at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:70)
at org.apache.mahout.classifier.naivebayes.test.TestNaiveBayesDriver.main(TestNaiveB ayesDriver.java:66)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java :43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.apache.hadoop.util.ProgramDriver$ProgramDescription.invoke(ProgramDriver.java :72)
at org.apache.hadoop.util.ProgramDriver.run(ProgramDriver.java:144)
at org.apache.hadoop.util.ProgramDriver.driver(ProgramDriver.java:152)
at org.apache.mahout.driver.MahoutDriver.main(MahoutDriver.java:195)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java :43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.apache.hadoop.util.RunJar.main(RunJar.java:212)
I am following the example from http://www.packtpub.com/article/implementing-the-na%C3%AFve-bayes-classifier-in-mahout and also tried the seqdumper on labelindex and can see the keys and values in it.
I am using Hadoop 2.2,Mahout 1.0 and whole environment is setup on Amazon EC2.
Please help me out.Am I doing something wrong ?

Answer 1

I think mahout is not compatible with your hadoop version, you should download the 1.1.0 or 1.2.0 versions of hadoop.
this will probabely fix your problem.

Answer 2

I guess you have your files in local. I also had this problem and I fixed it when I changed the files to HDFS