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Posted to dev@mahout.apache.org by "Raphael Cendrillon (Commented) (JIRA)" <ji...@apache.org> on 2011/12/12 01:26:30 UTC

[jira] [Commented] (MAHOUT-923) Row mean job for PCA

    [ https://issues.apache.org/jira/browse/MAHOUT-923?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13167291#comment-13167291 ] 

Raphael Cendrillon commented on MAHOUT-923:
-------------------------------------------

It might be worthwhile to pull this into a seperate issue. Here's a patch with a simple job to calculate the row mean (column-wise mean). One outstanding issue is the combiner, this requires a wrtiable class IntVectorTupleWritable, where the Int stores the number of rows, and the Vector stores the column-wise sum.
Does a class like this already exist?
                
> Row mean job for PCA
> --------------------
>
>                 Key: MAHOUT-923
>                 URL: https://issues.apache.org/jira/browse/MAHOUT-923
>             Project: Mahout
>          Issue Type: Improvement
>          Components: Math
>    Affects Versions: 0.6
>            Reporter: Raphael Cendrillon
>            Assignee: Raphael Cendrillon
>             Fix For: Backlog
>
>         Attachments: MAHOUT-923.patch
>
>
> Add map reduce job for calculating mean row (column-wise mean) of a Distributed Row Matrix for use in PCA.

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