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Mahout >> mail # dev >> Distributed User-based Collaborative Filtering

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Re: Distributed User-based Collaborative Filtering
good job!

2012/5/1 Kris Jack <[EMAIL PROTECTED]>

> Hello,
> I recently implemented a distributed user-based collaborative filtering
> algorithm.  I've tested it experimentally and found that it is better
> suited
> to Mendeley's data set for generating recommendations than the item-based
> implementation
> (
> http://www.slideshare.net/KrisJack/mahout-becomes-a-researcher-large-scale-recommendations-at-mendeley
> ).
> This is mostly because Mendeley's data set has far more items than users.
> I'd like to contribute this code to the Mahout project.  This will be the
> first patch that I write for Mahout so I'm following the instructions at
> https://cwiki.apache.org/MAHOUT/how-to-contribute.html
> In brief, so far I've taken the code for the existing
> org.apache.mahout.cf.taste.hadoop.item.RecommenderJob and created a new
> org.apache.mahout.cf.taste.hadoop.user.RecommenderJob.  With help from Sean
> Owen, I followed a similar approach to the item-based implementation, but
> multiplied a user-user matrix with a user-item vector rather than an
> item-item matrix with an item-user vector.  The result of the
> multiplication
> then needs to be transposed in order to output recommendations by user id.
> Rather than changing the item-based code, I've created new classes for the
> user-based version, which tend to be modified versions of the originals.
>  It
> would be much tidier to merge these together, where possible, and to
> parametrise them.  I didn't want to change the item-based code straight
> off,
> however, without consulting you all.
> Would be great to get some feedback.
> Best,
> Kris
> --
> View this message in context:
> http://lucene.472066.n3.nabble.com/Distributed-User-based-Collaborative-Filtering-tp3952692.html
> Sent from the Mahout Developer List mailing list archive at Nabble.com.

Best regards,