Hi Sebastian and Sean
Thanks for your help.
I re-read the code again (debug seems to be very difficult for me to setup the
environment) and find the line in SimilarityMatrixRowWrapperMapper, i past it
below with the comments:
/* remove self similarity */
similarityMatrixRow.set(key.get(), Double.NaN);
I think the meanning is to mark the similarity between Item X and Item X (the
identical one) as NaN, but it doesn't exclude Item X from recommendation, then
in AggregateAndRecommendReducer, it uses simColumn.times(prefValue) as part of
the formula to calculate the preferences for all items that similar to Item i
(it could be Item X or some other item), then return the top 10 (default) for a
user.
During this process, i cannot see any code to exclude an item which the user
has already given preference from recommendation.
Correct me if i miss something, thank you guys.
Cheers Ramon
> Date: Thu, 20 Oct 2011 13:59:28 +0100
> Subject: Re: Recommend result contains item which user has already given
> preference, is that correct?
> From: [email protected]
> To: [email protected]
>
> Ah OK, figured as much. WangRamon does that answer your question
> and/or can you debug to see if this is happening, not happening for
> you in your use case?
>
> On Thu, Oct 20, 2011 at 1:42 PM, Sebastian Schelter <[email protected]> wrote:
> > It's still included in SimilarityMatrixRowWrapperMapper. We also have a
> > unit test that checks whether a user is only recommended unknown items
> > which still works.
