Yes that is the intended usage pattern for the evaluator. On Nov 15, 2011 11:56 AM, "Anatoliy Kats" <a.k...@rambler-co.ru> wrote:
> Duh! Thanks:) I can't feed a rescorer to the evaluator, but I can work > around that: I am already creating my own recommender class by subclassing > the ItemBasedRecommender, so I can just overload the recommend(..) to > super.recommend(.., IDRescorer). It seems like a more elegant solution > than adding the rescorer to the evaluator. > > On 11/15/2011 03:38 PM, Sean Owen wrote: > >> This is exactly what Rescorer is for in the recommend() method. Does that >> suit? >> On Nov 15, 2011 11:37 AM, "Anatoliy Kats"<a.k...@rambler-co.ru> wrote: >> >> Hi all, >>> >>> I have a use case for Taste where we should use all available items for >>> computation of user similarity, but only some items are eligible to be >>> recommended. The reason is that items expire: goods get discontinued, >>> for >>> example. The fact that a user bought something now discontinued is >>> important for finding similar users, but we cannot recommend it. One way >>> of solving this is using mahout to generate recommendations, and then >>> post-process it to remove ineligible items. But this can run into >>> performance issues if the set of ineligible items is large. Also, the >>> evaluation framework is not designed to handle this kind of a >>> restriction. >>> >>> I can contribute a patch, but since I am new to the project, I need some >>> help with the software engineering from the regular contributors. How >>> would I design the necessary classes? One idea I considered was using >>> the >>> existing tools for candidate item strategy. This has two downsides: you >>> can only use one candidate item strategy at a time, so having an eligible >>> set would make it impossible to have a candidate item strategy. Also, >>> the >>> evaluator doesn't take the candidate item strategy into account. So, I >>> suppose I could try writing an EligibleSetCandidateItemStrate****gy that >>> takes another CandidateItemStrategy and applies it as well, and I can >>> add a >>> new evaluator that takes eligible sets into account. I don't know the >>> thinking behind the design, so I don't know if this is a good idea or >>> not. >>> Can we agree on a design before I get started? >>> >>> Cheers, >>> >>> Anatoliy >>> >>> >
