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From Pat Ferrel <>
Subject Re: Setting up a recommender
Date Tue, 30 Jul 2013 15:24:19 GMT
Actually I'm not sure the downsampling is best put in RowSimilarityJob since that doesn't work
for the XRecommender. The similarity matrix there is calculated by [B'A] matrix multiply.
RSJ would be great if it could work on two DRMs, then we could use other similarity measures
(LLR please).

Also I'm not sure if its needed in RSJ since I use PreparePreferenceMatrixJob for the RecommenderJob,
which calculates the main action item similarity matrix (using RSJ in any case).

But for the XRecommender I modified PreparePreferenceMatrixJob to create two DRMs and called
it PreparePreferenceMatrixesJob. It has downsampling in it, if you mean limiting the number
of prefs per user. Check if I'm wrong.

On Jul 29, 2013, at 10:17 PM, Sebastian Schelter <> wrote:

Downsampling is now moved directly into RowSimilarityJob. I'll have a
look at Pat's code later this week.

On 23.07.2013 19:38, Ted Dunning wrote:
> On Tue, Jul 23, 2013 at 9:39 AM, Pat Ferrel <> wrote:
>> This pipeline lacks downsampling since I had to replace
>> PreparePreferenceMatrixJob and potentially LLR for [B'A]. I assume
>> Sebastian is the person to talk to about these bits?
> I think that is a good source.  If you post your code, he may be able to
> comment on how to integrate the down-sampling in a general way.

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