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Magun rowSimilarity

I am trying to calculate line similarity between Wikipedia documents. I have tf-idf vectors in format Key class: class org.apache.hadoop.io.Text Value Class: class org.apache.mahout.math.VectorWritable. I follow a quick text analysis: https://cwiki.apache.org/confluence/display/MAHOUT/Quick+tour+of+text+analysis+using+the+Mahout+command+line

I created the mahout matrix as follows:

mahout rowid \
   -i wikipedia-vectors/tfidf-vectors/part-r-00000
   -o wikipedia-matrix

I got the number of rows and columns generated:

vectors.RowIdJob: Wrote out matrix with 4587604 rows and 14121544 columns to wikipedia-matrix/matrix

The matrix has the format Key class: class org.apache.hadoop.io.IntWritable Value Class: class org.apache.mahout.math.VectorWritable

I also have a document docIndexwith the following format:Key class: class org.apache.hadoop.io.IntWritable Value Class: class org.apache.hadoop.io.Text

Then, when I run the job in row order

mahout rowsimilarity 
   -i wikipedia-matrix/matrix 
   -o wikipedia-similarity 
   -r 4587604
   --similarityClassname SIMILARITY_COSINE
   -m 50
   -ess

I get the following error:

13/08/25 15:18:18 INFO mapred.JobClient: Task Id : attempt_201308161435_0364_m_000001_1, Status : FAILED
java.lang.ClassCastException: org.apache.hadoop.io.Text cannot be cast to org.apache.mahout.math.VectorWritable
    at org.apache.mahout.math.hadoop.similarity.cooccurrence.RowSimilarityJob$VectorNormMapper.map(RowSimilarityJob.java:183)
    at org.apache.hadoop.mapreduce.Mapper.run(Mapper.java:144)
    at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:648)
    at org.apache.hadoop.mapred.MapTask.run(MapTask.java:322)
    at org.apache.hadoop.mapred.Child$4.run(Child.java:266)
    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:1278)
    at org.apache.hadoop.mapred.Child.main(Child.java:260)

Can someone please help me with a mistake? I'm not sure where this org.apache.hadoop.io.Textone is when the input matrix has the formatKey class: class org.apache.hadoop.io.IntWritable Value Class: class org.apache.mahout.math.VectorWritable

Many thanks.

Best, Dragan

+2
1

, :

hadoop jar mahout-examples-0.9-SNAPSHOT.jar 
org.apache.mahout.math.hadoop.similarity.cooccurrence.RowSimilarityJob 
-i /user/dmilchev/wikipedia-matrix/matrix 
-o /user/dmilchev/wikipedia-similarity 
-r 4587604 --similarityClassname SIMILARITY_COSINE -m 50 -ess

.

+3

Source: https://habr.com/ru/post/1584360/

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