Introducing Apache Mahout Article posted on IBM devWorks
My first article on Apache Mahout was just published on IBM devWorks. It’s targeted at people just getting started with machine learning and Mahout. You can read the article at Introducing Apache Mahout. Feedback welcome.
Hi,
That is a great introduction for Apache mahout. thanks for that.:)
I was trying to run reccomender jobs on Hadoop. But had some errors. I will appreciate if you can help on this.
The error is :
09/12/02 19:49:27 INFO mapred.FileInputFormat: Total input paths to process : 1
09/12/02 19:49:30 INFO mapred.JobClient: Running job: job_200912021947_0002
09/12/02 19:49:31 INFO mapred.JobClient: map 0% reduce 0%
09/12/02 19:50:01 INFO mapred.JobClient: Task Id : attempt_200912021947_0002_m_000000_0, Status : FAILED
java.lang.RuntimeException: Error in configuring object
at org.apache.hadoop.util.ReflectionUtils.setJobConf(ReflectionUtils.java:93)
at org.apache.hadoop.util.ReflectionUtils.setConf(ReflectionUtils.java:64)
at org.apache.hadoop.util.ReflectionUtils.newInstance(ReflectionUtils.java:117)
at org.apache.hadoop.mapred.MapTask.runOldMapper(MapTask.java:354)
at org.apache.hadoop.mapred.MapTask.run(MapTask.java:307)
at org.apache.hadoop.mapred.Child.main(Child.java:170)
Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.apache.hadoop.util.ReflectionUtils.setJobConf(ReflectionUtils.java:88)
… 5 more
Caused by: java.lang.RuntimeException: java.lang.RuntimeException: class org.apache.mahout.cf.taste.hadoop.RecommenderMapper not org.apache.hadoop.mapred.Mapper
at org.apache.hadoop.conf.Configuration.getClass(Configuration.java:840)
at org.apache.hadoop.mapred.JobConf.getMapperClass(JobConf.java:771)
at org.apache.hadoop.mapred.MapRunner.configure(MapRunner.java:34)
… 10 more
Caused by: java.lang.RuntimeException: class org.apache.mahout.cf.taste.hadoop.RecommenderMapper not org.apache.hadoop.mapred.Mapper
at org.apache.hadoop.conf.Configuration.getClass(Configuration.java:834)
… 12 more
09/12/02 19:50:03 INFO mapred.JobClient: Task Id : attempt_200912021947_0002_m_000001_0, Status : FAILED
java.lang.RuntimeException: Error in configuring object
at org.apache.hadoop.util.ReflectionUtils.setJobConf(ReflectionUtils.java:93)
at org.apache.hadoop.util.ReflectionUtils.setConf(ReflectionUtils.java:64)
at org.apache.hadoop.util.ReflectionUtils.newInstance(ReflectionUtils.java:117)
at org.apache.hadoop.mapred.MapTask.runOldMapper(MapTask.java:354)
at org.apache.hadoop.mapred.MapTask.run(MapTask.java:307)
at org.apache.hadoop.mapred.Child.main(Child.java:170)
Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.apache.hadoop.util.ReflectionUtils.setJobConf(ReflectionUtils.java:88)
… 5 more
Caused by: java.lang.RuntimeException: java.lang.RuntimeException: class org.apache.mahout.cf.taste.hadoop.RecommenderMapper not org.apache.hadoop.mapred.Mapper
at org.apache.hadoop.conf.Configuration.getClass(Configuration.java:840)
at org.apache.hadoop.mapred.JobConf.getMapperClass(JobConf.java:771)
at org.apache.hadoop.mapred.MapRunner.configure(MapRunner.java:34)
… 10 more
Caused by: java.lang.RuntimeException: class org.apache.mahout.cf.taste.hadoop.RecommenderMapper not org.apache.hadoop.mapred.Mapper
at org.apache.hadoop.conf.Configuration.getClass(Configuration.java:834)
… 12 more
09/12/02 19:50:10 INFO mapred.JobClient: Task Id : attempt_200912021947_0002_m_000001_1, Status : FAILED
java.lang.RuntimeException: Error in configuring object
at org.apache.hadoop.util.ReflectionUtils.setJobConf(ReflectionUtils.java:93)
at org.apache.hadoop.util.ReflectionUtils.setConf(ReflectionUtils.java:64)
at org.apache.hadoop.util.ReflectionUtils.newInstance(ReflectionUtils.java:117)
at org.apache.hadoop.mapred.MapTask.runOldMapper(MapTask.java:354)
at org.apache.hadoop.mapred.MapTask.run(MapTask.java:307)
at org.apache.hadoop.mapred.Child.main(Child.java:170)
Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.apache.hadoop.util.ReflectionUtils.setJobConf(ReflectionUtils.java:88)
… 5 more
Caused by: java.lang.RuntimeException: java.lang.RuntimeException: class org.apache.mahout.cf.taste.hadoop.RecommenderMapper not org.apache.hadoop.mapred.Mapper
at org.apache.hadoop.conf.Configuration.getClass(Configuration.java:840)
at org.apache.hadoop.mapred.JobConf.getMapperClass(JobConf.java:771)
at org.apache.hadoop.mapred.MapRunner.configure(MapRunner.java:34)
… 10 more
Ca
the command is:
bin/hadoop jar org.apache.mahout.cf.taste.hadoop.RecommenderJob org.apache.mahout.cf.taste.impl.recommender.GenericItemBasedRecommender 2 /In/file.0 /In/.file.0.crc Out