If you are using one of the standard RecommenderEvaluator
implementations, then this will not happen. It already splits the data
into 'test' and 'training' data. It will not try to estimate a
preference that is already known in the training data, no.

On Thu, Nov 19, 2009 at 5:40 PM, jamborta <[email protected]> wrote:
>
> sorry, I have one more thing to add, in GenericUserBasedRecommender this is
> the method that estimates the preference:
>
>  public float estimatePreference(long userID, long itemID) throws
> TasteException {
>    DataModel model = getDataModel();
>    Float actualPref = model.getPreferenceValue(userID, itemID);
>    if (actualPref != null) {
>      return actualPref;
>    }
>    long[] theNeighborhood = neighborhood.getUserNeighborhood(userID);
>    return doEstimatePreference(userID, theNeighborhood, itemID);
>  }
>
> but I try to estimate from the training set, so obviously the userID and
> itemID exsist in the model, therefore it returns the actualPref. that's why
> I get 0 as a result.
> --
> View this message in context: 
> http://old.nabble.com/evaluating-recommender-systems-tp26421408p26421411.html
> Sent from the Mahout User List mailing list archive at Nabble.com.
>
>

Reply via email to