public override double GetEvaluation(IDictionary<User, ICollection<Preference>> testUserPrefs,
Recommender recommender)
{
RunningAverage average = new FullRunningAverage();
foreach (KeyValuePair<User, ICollection<Preference>> entry in testUserPrefs)
{
foreach (Preference realPref in entry.Value)
{
User testUser = entry.Key;
try
{
double estimatedPreference =
recommender.EstimatePreference(testUser.ID, realPref.Item.ID);
if (!double.IsNaN(estimatedPreference))
{
double diff = realPref.Value - estimatedPreference;
average.AddDatum(diff * diff);
}
}
catch (NoSuchElementException nsee)
{
// It's possible that an item exists in the test data but not training data in which case
// NSEE will be thrown. Just ignore it and move on.
log.Info("Element exists in test data but not training data: " + testUser.ID, nsee);
}
}
}
return Math.Sqrt(average.Average);
}
public override double GetEvaluation(IDictionary <User, ICollection <Preference> > testUserPrefs,
Recommender recommender)
{
RunningAverage average = new FullRunningAverage();
foreach (KeyValuePair <User, ICollection <Preference> > entry in testUserPrefs)
{
foreach (Preference realPref in entry.Value)
{
User testUser = entry.Key;
try
{
double estimatedPreference =
recommender.EstimatePreference(testUser.ID, realPref.Item.ID);
if (!double.IsNaN(estimatedPreference))
{
double diff = realPref.Value - estimatedPreference;
average.AddDatum(diff * diff);
}
}
catch (NoSuchElementException nsee)
{
// It's possible that an item exists in the test data but not training data in which case
// NSEE will be thrown. Just ignore it and move on.
log.Info("Element exists in test data but not training data: " + testUser.ID, nsee);
}
}
}
return(Math.Sqrt(average.Average));
}
public Double GetValue(Pair <object, object> key)
{
Object userID = key.First;
Object itemID = key.Second;
if (log.IsDebugEnabled)
{
log.Debug("Retrieving estimated preference for user ID '" + userID + "\' and item ID \'" +
itemID.ToString() + '\'');
}
return(recommender.EstimatePreference(userID, itemID));
}
public void TestEstimatePref()
{
Recommender recommender = buildRecommender();
Assert.AreEqual(0.3, recommender.EstimatePreference("test1", "2"));
}
public void TestEstimatePref()
{
Recommender recommender = buildRecommender();
Assert.AreEqual(0.34803885284992736, recommender.EstimatePreference("test1", "2"), EPSILON);
}
