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From Em <>
Subject Re: Exclude by RuleSet
Date Sat, 02 Jul 2011 13:53:02 GMT
Hi Steven,

That would be the alternative. Create different data-models per
category, yes.

Does this affect the quality of your recommendations in comparison to a
data-model that contains also not-relevant data for the current
category/situation/social-graph but the unwanted recommendations are
filtered out by a Rescorer?


Am 02.07.2011 15:22, schrieb Steven Bourke:
> Assuming you have the technical resources, one approach could involve just
> containing different 'conditions' into different data models.
> For instance I have one setup that only has users from someones social
> graph, and another that includes all my users. When generating
> recommendations I just point it to whichever datasource is required.
> On Fri, Jul 1, 2011 at 7:25 PM, Sean Owen <> wrote:
>> From what you describe so far, you do not need any new code. A
>> Rescorer does what you want, I believe. If not, maybe you can explain
>> more about what it's not doing that you want it to do. A Rescorer to
>> exclude items is probably always a good idea as it saves computation.
>> On Fri, Jul 1, 2011 at 7:03 PM, Em <> wrote:
>>> Hi Sean,
>>> I am not very familiar with the code itself, however I have no problem
>>> with digging into it.
>>> I guess the CandidateItemStrategy and the Rescorer are usable for all
>>> kinds of recommendations: user-user, user-item, item-item etc. and so I
>>> can create a generic (or general) implementation for the problem?
>>> Could you explain more of the tradeoffs for both
>>> implementation-possibilities, please?
>>> Regards,
>>> Em
>>> Am 01.07.2011 19:01, schrieb Sean Owen:
>>>> The short answer is that you'd have to modify the code to inject this
>>>> kind of logic -- though you might get away with just using a custom
>>>> CandidateItemStrategy in an item-based recommender.
>>>> A Rescorer will cause it to not bother computing estimated values for
>>>> unwanted items though, so I think it already does what you intend.
>>>> On Fri, Jul 1, 2011 at 5:56 PM, Em <>
>> wrote:
>>>>> Hello list,
>>>>> is it possible to filter out some items/users from the
>>>>> recommendation-process?
>>>>> In some cases one does not want to include information from some
>> sources in
>>>>> special situations.
>>>>> As an example you can imagine an onlineshop. If you click on the
>> category
>>>>> "women" it would be the best to only show recommendations for this
>>>>> main-category rather than also showing some stuff for men.
>>>>> A Rescorer could be a solution to filter out those unwanted results
>> *after*
>>>>> the big part is done (am I correct?), however I do not want to spend
>>>>> ressources on computing probabilities for items that are definitly
>> unwanted
>>>>> for the resultset.
>>>>> What I want is something like a
>>>>> SELECT col1, col2, col3 FROM myData WHERE category = "women" OR
>> category =
>>>>> "subcategoryOfWomen"
>>>>> and than do the computation on top of this dataset.
>>>>> Is this possible with Mahout?
>>>>> Regards,
>>>>> Em
>>>>> --
>>>>> View this message in context:
>>>>> Sent from the Mahout User List mailing list archive at

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