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Posted to user@mahout.apache.org by Lance Norskog <go...@gmail.com> on 2012/01/20 23:41:36 UTC
Re: Help with MatrixDumper
Dumping vectors is a separate job called 'vectordump'.
On Fri, Jan 20, 2012 at 1:54 PM, Suneel Marthi <su...@yahoo.com> wrote:
> Mahout Version: 0.6-SNAPSHOT from trunk
>
>
> I convert my vectors (generated by seq2sparse) to matrix using the RowIdJob.
>
> RowIdJob creates a matrix (IntWritable, VectorWritable) and a docIndex (IntWritable, Text).
>
>
> I am now trying to dump the matrix generated using MatrixDumper and I see this error:-
>
> Exception in thread "main" java.lang.ClassCastException: org.apache.mahout.math.VectorWritable cannot be cast to org.apache.mahout.math.MatrixWritable
> at org.apache.mahout.utils.MatrixDumper.exportCSV(MatrixDumper.java:70)
> at org.apache.mahout.utils.MatrixDumper.run(MatrixDumper.java:63)
> at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:65)
> at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:79)
> at org.apache.mahout.utils.MatrixDumper.main(MatrixDumper.java:50)
> 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.ProgramDriver$ProgramDescription.invoke(ProgramDriver.java:68)
> at org.apache.hadoop.util.ProgramDriver.driver(ProgramDriver.java:139)
> at org.apache.mahout.driver.MahoutDriver.main(MahoutDriver.java:188)
> 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.RunJar.main(RunJar.java:156)
>
>
> Obviously the MatrixDumper is expecting to retrieve a MatrixWritable, but what's being written into the matrix is a VectorWritable.
>
> Am I using MatrixDumper the right way or do we have an issue here?
--
Lance Norskog
goksron@gmail.com