public void TestTimeSplit()
{
var ratings = new TimedRatings();
ratings.Add(0, 0, 5.0f, new DateTime(2011, 10, 31));
ratings.Add(0, 1, 4.5f, new DateTime(2011, 11, 1));
ratings.Add(1, 0, 1.0f, new DateTime(2011, 10, 31));
ratings.Add(1, 1, 2.5f, new DateTime(2011, 11, 2));
var split1 = new RatingsChronologicalSplit(ratings, new DateTime(2011, 11, 2));
Assert.AreEqual(3, split1.Train[0].Count);
Assert.AreEqual(1, split1.Test[0].Count);
Assert.AreEqual(2, split1.Train[0].ByUser[0].Count);
Assert.AreEqual(1, split1.Train[0].ByUser[1].Count);
Assert.AreEqual(0, split1.Test[0].ByUser[0].Count);
Assert.AreEqual(1, split1.Test[0].ByUser[1].Count);
Assert.AreEqual(new DateTime(2011, 10, 31), split1.Train[0].EarliestTime);
Assert.AreEqual(new DateTime(2011, 11, 1), split1.Train[0].LatestTime);
Assert.AreEqual(new DateTime(2011, 11, 2), split1.Test[0].EarliestTime);
Assert.AreEqual(new DateTime(2011, 11, 2), split1.Test[0].LatestTime);
var split2 = new RatingsChronologicalSplit(ratings, new DateTime(2011, 11, 1));
Assert.AreEqual(2, split2.Train[0].Count);
Assert.AreEqual(2, split2.Test[0].Count);
Assert.AreEqual(1, split2.Train[0].ByUser[0].Count);
Assert.AreEqual(1, split2.Train[0].ByUser[1].Count);
Assert.AreEqual(1, split2.Test[0].ByUser[0].Count);
Assert.AreEqual(1, split2.Test[0].ByUser[1].Count);
Assert.AreEqual(new DateTime(2011, 10, 31), split2.Train[0].EarliestTime);
Assert.AreEqual(new DateTime(2011, 10, 31), split2.Train[0].LatestTime);
Assert.AreEqual(new DateTime(2011, 11, 1), split2.Test[0].EarliestTime);
Assert.AreEqual(new DateTime(2011, 11, 2), split2.Test[0].LatestTime);
}
public void TestRatioSplit()
{
var ratings = new TimedRatings();
ratings.Add(0, 0, 5.0f, new DateTime(2011, 10, 31));
ratings.Add(0, 1, 4.5f, new DateTime(2011, 11, 1));
ratings.Add(0, 2, 5.0f, new DateTime(2011, 11, 3));
ratings.Add(0, 3, 4.5f, new DateTime(2011, 11, 4));
ratings.Add(1, 0, 1.0f, new DateTime(2011, 10, 31));
ratings.Add(1, 1, 2.5f, new DateTime(2011, 11, 2));
ratings.Add(1, 2, 1.0f, new DateTime(2011, 12, 1));
ratings.Add(1, 3, 2.5f, new DateTime(2011, 12, 4));
var split1 = new RatingsPerUserChronologicalSplit(ratings, 0.25);
Assert.AreEqual(6, split1.Train[0].Count);
Assert.AreEqual(2, split1.Test[0].Count);
Assert.AreEqual(3, split1.Train[0].ByUser[0].Count);
Assert.AreEqual(3, split1.Train[0].ByUser[1].Count);
Assert.AreEqual(1, split1.Test[0].ByUser[0].Count);
Assert.AreEqual(1, split1.Test[0].ByUser[1].Count);
var split2 = new RatingsPerUserChronologicalSplit(ratings, 0.5);
Assert.AreEqual(4, split2.Train[0].Count);
Assert.AreEqual(4, split2.Test[0].Count);
Assert.AreEqual(2, split2.Train[0].ByUser[0].Count);
Assert.AreEqual(2, split2.Train[0].ByUser[1].Count);
Assert.AreEqual(2, split2.Test[0].ByUser[0].Count);
Assert.AreEqual(2, split2.Test[0].ByUser[1].Count);
}
public static IRatings CreateRandomTimedRatings(int num_users, int num_items, int num_ratings)
{
var random = MyMediaLite.Random.GetInstance();
var ratings = new TimedRatings();
for (int i = 0; i < num_ratings; i++)
{
int user_id = random.Next(num_users);
int item_id = random.Next(num_items);
int rating_value = 1 + random.Next(5);
ratings.Add(user_id, item_id, rating_value, DateTime.Now);
}
return(ratings);
}
/// <summary>Read in rating data from a TextReader</summary>
/// <param name="reader">the <see cref="TextReader"/> to read from</param>
/// <param name="user_mapping">mapping object for user IDs</param>
/// <param name="item_mapping">mapping object for item IDs</param>
/// <param name="test_rating_format">whether there is a rating column in each line or not</param>
/// <returns>the rating data</returns>
static public ITimedRatings Read(
TextReader reader,
IMapping user_mapping = null, IMapping item_mapping = null,
TestRatingFileFormat test_rating_format = TestRatingFileFormat.WITH_RATINGS)
{
if (user_mapping == null)
{
user_mapping = new IdentityMapping();
}
if (item_mapping == null)
{
item_mapping = new IdentityMapping();
}
var ratings = new TimedRatings();
string[] separators = { "::" };
string line;
int seconds_pos = test_rating_format == TestRatingFileFormat.WITH_RATINGS ? 3 : 2;
while ((line = reader.ReadLine()) != null)
{
string[] tokens = line.Split(separators, StringSplitOptions.None);
if (test_rating_format == TestRatingFileFormat.WITH_RATINGS && tokens.Length < 4)
{
throw new FormatException("Expected at least 4 columns: " + line);
}
if (test_rating_format == TestRatingFileFormat.WITHOUT_RATINGS && tokens.Length < 3)
{
throw new FormatException("Expected at least 3 columns: " + line);
}
int user_id = user_mapping.ToInternalID(tokens[0]);
int item_id = item_mapping.ToInternalID(tokens[1]);
float rating = test_rating_format == TestRatingFileFormat.WITH_RATINGS ? float.Parse(tokens[2], CultureInfo.InvariantCulture) : 0;
long seconds = uint.Parse(tokens[seconds_pos]);
var time = new DateTime(seconds * 10000000L).AddYears(1969);
var offset = TimeZone.CurrentTimeZone.GetUtcOffset(time);
time -= offset;
ratings.Add(user_id, item_id, rating, time);
}
return(ratings);
}
public override void Train(Split split)
{
// Convert trainset to MyMediaLite trianset format
if (DataType == IO.DataType.Ratings)
{
var mmlFeedback = new Ratings();
foreach (var feedback in split.Train)
{
var rating = (Rating)feedback;
mmlFeedback.Add(UsersMap.ToInternalID(rating.User.Id), ItemsMap.ToInternalID(rating.Item.Id), rating.Value);
}
((IRatingPredictor)MmlRecommenderInstance).Ratings = mmlFeedback;
}
else if (DataType == IO.DataType.TimeAwareRating)
{
var mmlFeedback = new TimedRatings();
var firstRatingMl10M = new DateTime(1998, 11, 1);
foreach (var feedback in split.Train)
{
var rating = (Rating)feedback;
var time = firstRatingMl10M.AddDays(double.Parse(feedback.Attributes["timestamp"].Value));
mmlFeedback.Add(UsersMap.ToInternalID(rating.User.Id), ItemsMap.ToInternalID(rating.Item.Id),
rating.Value, time);
}
((ITimeAwareRatingPredictor)MmlRecommenderInstance).Ratings = mmlFeedback;
}
else
{
var mmlFeedback = new PosOnlyFeedback <SparseBooleanMatrix>();
foreach (var feedback in split.Train)
{
mmlFeedback.Add(UsersMap.ToInternalID(feedback.User.Id), ItemsMap.ToInternalID(feedback.Item.Id));
}
((ItemRecommender)MmlRecommenderInstance).Feedback = mmlFeedback;
if (MmlRecommenderInstance is IModelAwareRecommender)
{
((IModelAwareRecommender)MmlRecommenderInstance).Model = this;
}
}
Logger.Current.Trace("Training with MyMediaLite recommender...");
PureTrainTime = (int)Wrap.MeasureTime(delegate() { MmlRecommenderInstance.Train(); }).TotalMilliseconds;
}
