Hi everybody,
I have completed my first Mahout experiment with an Hadoop local
installation (single machine) and I obtained different results from Scilab
and the Mahout Distributed Lanczos Solver. Could someone explain why this
happens? Am I doing something wrong?
This is my matrix
2,0,8,6,0
1,6,0,1,7
5,0,7,4,0
7,0,8,5,0
0,10,0,0,7
This is my Mahout invocation
./hadoop jar
/home/hadoop-user/mahout/mahout-distribution-0.5/mahout-examples-0.5-job.jar
org.apache.mahout.math.hadoop.decomposer.DistributedLanczosSolver --input
/user/hadoop-user/mahout-input --output /user/hadoop-user/mahout-output
--numCols 5 --numRows 5 --cleansvd "true" --rank 5
These are the Mahout results
11/11/08 12:45:04 INFO lanczos.LanczosSolver: 4 passes through the corpus so
far...
11/11/08 12:45:04 INFO lanczos.LanczosSolver: Lanczos iteration complete -
now to diagonalize the tri-diagonal auxiliary matrix.
11/11/08 12:45:04 INFO lanczos.LanczosSolver: Eigenvector 0 found with
eigenvalue 0.0
11/11/08 12:45:04 INFO lanczos.LanczosSolver: Eigenvector 1 found with
eigenvalue 1.0869992925693057
11/11/08 12:45:04 INFO lanczos.LanczosSolver: Eigenvector 2 found with
eigenvalue 3.4305998309907
11/11/08 12:45:04 INFO lanczos.LanczosSolver: Eigenvector 3 found with
eigenvalue 15.171371217397603
11/11/08 12:45:04 INFO lanczos.LanczosSolver: Eigenvector 4 found with
eigenvalue 17.918370809987454
11/11/08 12:45:04 INFO lanczos.LanczosSolver: LanczosSolver finished.
And these are the results from Scilab (svd(X))
-->[U,S,V]=svd(X);
-->S
S =
17.918371 0. 0. 0. 0.
0. 15.171372 0. 0. 0.
0. 0. 3.564002 0. 0.
0. 0. 0. 1.9842282 0.
0. 0. 0. 0. 0.3495557
thank you,
Alfredo
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