PlusAnonymousConcurrentUserDataModel example in java

Question

i am trying to write a recommender systems code that should use the function PlusAnonymousConcurrentUserDataModel to get a temporary profile for a new user.

l am using mahout Can anyone show an example?

Any help will be appreciated

Cheers kingsley

Answer 1

I assumed you already have a model running, so here is the code you need around that to get PlusAnonymousConcurrentUserDataModel working.

// Build your datamodel
DataModel dataModel = ...

// Build anonymous data model with previous datamodel
PlusAnonymousConcurrentUserDataModel anonymousDataModel = new PlusAnonymousConcurrentUserDataModel(dataModel, 100); 

// Configure and build your recommender 
UserSimilarity similarity = new PearsonCorrelationSimilarity(model);
UserNeighborhood neighborhood = new NearestNUserNeighborhood(25, similarity, model);//

recommender = new CachingRecommender(new GenericUserBasedRecommender(anonymousDataModel, neighborhood, similarity));

now, if the user exists, you can retrieve recommendations like always. Otherwise:

//Get new user id
long newUserID = anonymousDataModel.takeAvailableUser();

// fill a Mahout data structure with the user's preferences
GenericUserPreferenceArray tempPrefs = new GenericUserPreferenceArray(dUserPreferences.size());


int i = 0;
for(Map.Entry<Long, Float> entry : dUserPreferences.entrySet()) {
    Long key = entry.getKey();
    Float value = entry.getValue();

    tempPrefs.setUserID(i, newUserID);
    tempPrefs.setItemID(i, key);
    tempPrefs.setValue(i, value);

    i++;
}

// Add the temporaly preferences to model
anonymousDataModel.setTempPrefs(tempPrefs, newUserID);

// And get recommendations
List<RecommendedItem> recommendations = recommender.recommend(newUserID, count);