public void TestRescorer()
{
List <User> users = new List <User>(3);
users.Add(GetUser("test1", 0.1, 0.2));
users.Add(GetUser("test2", 0.2, 0.3, 0.3, 0.6));
users.Add(GetUser("test3", 0.4, 0.4, 0.5, 0.9));
DataModel dataModel = new GenericDataModel(users);
Item item1 = new GenericItem <String>("0");
Item item2 = new GenericItem <String>("1");
Item item3 = new GenericItem <String>("2");
Item item4 = new GenericItem <String>("3");
ICollection <GenericItemCorrelation.ItemItemCorrelation> correlations =
new List <GenericItemCorrelation.ItemItemCorrelation>(6);
correlations.Add(new GenericItemCorrelation.ItemItemCorrelation(item1, item2, 1.0));
correlations.Add(new GenericItemCorrelation.ItemItemCorrelation(item1, item3, 0.5));
correlations.Add(new GenericItemCorrelation.ItemItemCorrelation(item1, item4, 0.2));
correlations.Add(new GenericItemCorrelation.ItemItemCorrelation(item2, item3, 0.7));
correlations.Add(new GenericItemCorrelation.ItemItemCorrelation(item2, item4, 0.5));
correlations.Add(new GenericItemCorrelation.ItemItemCorrelation(item3, item4, 0.9));
ItemCorrelation correlation = new GenericItemCorrelation(correlations);
Recommender recommender = new GenericItemBasedRecommender(dataModel, correlation);
IList <RecommendedItem> originalRecommended = recommender.Recommend("test1", 2);
IList <RecommendedItem> rescoredRecommended =
recommender.Recommend("test1", 2, new ReversingRescorer <Item>());
Assert.IsNotNull(originalRecommended);
Assert.IsNotNull(rescoredRecommended);
Assert.AreEqual(2, originalRecommended.Count);
Assert.AreEqual(2, rescoredRecommended.Count);
Assert.AreEqual(originalRecommended[0].Item, rescoredRecommended[1].Item);
Assert.AreEqual(originalRecommended[1].Item, rescoredRecommended[0].Item);
}
public void TestHowMany()
{
List <User> users = new List <User>(3);
users.Add(GetUser("test1", 0.1, 0.2));
users.Add(GetUser("test2", 0.2, 0.3, 0.3, 0.6));
users.Add(GetUser("test3", 0.4, 0.4, 0.5, 0.9));
users.Add(GetUser("test4", 0.1, 0.4, 0.5, 0.8, 0.9, 1.0));
users.Add(GetUser("test5", 0.2, 0.3, 0.6, 0.7, 0.1, 0.2));
DataModel dataModel = new GenericDataModel(users);
IList <GenericItemCorrelation.ItemItemCorrelation> correlations =
new List <GenericItemCorrelation.ItemItemCorrelation>(6);
for (int i = 0; i < 6; i++)
{
for (int j = i + 1; j < 6; j++)
{
correlations.Add(
new GenericItemCorrelation.ItemItemCorrelation(new GenericItem <String>(i.ToString()),
new GenericItem <String>(j.ToString()),
1.0 / (1.0 + (double)i + (double)j)));
}
}
ItemCorrelation correlation = new GenericItemCorrelation(correlations);
Recommender recommender = new GenericItemBasedRecommender(dataModel, correlation);
IList <RecommendedItem> fewRecommended = recommender.Recommend("test1", 2);
IList <RecommendedItem> moreRecommended = recommender.Recommend("test1", 4);
for (int i = 0; i < fewRecommended.Count; i++)
{
Assert.AreEqual(fewRecommended[i].Item, moreRecommended[i].Item);
}
}
private static ItemBasedRecommender buildRecommender2()
{
List <User> users = new List <User>(4);
users.Add(GetUser("test1", 0.1, 0.3, 0.9, 0.8));
users.Add(GetUser("test2", 0.2, 0.3, 0.3, 0.4));
users.Add(GetUser("test3", 0.4, 0.3, 0.5, 0.1, 0.1));
users.Add(GetUser("test4", 0.7, 0.3, 0.8, 0.5, 0.6));
DataModel dataModel = new GenericDataModel(users);
ICollection <GenericItemCorrelation.ItemItemCorrelation> correlations =
new List <GenericItemCorrelation.ItemItemCorrelation>(10);
Item item1 = new GenericItem <String>("0");
Item item2 = new GenericItem <String>("1");
Item item3 = new GenericItem <String>("2");
Item item4 = new GenericItem <String>("3");
Item item5 = new GenericItem <String>("4");
correlations.Add(new GenericItemCorrelation.ItemItemCorrelation(item1, item2, 1.0));
correlations.Add(new GenericItemCorrelation.ItemItemCorrelation(item1, item3, 0.8));
correlations.Add(new GenericItemCorrelation.ItemItemCorrelation(item1, item4, -0.6));
correlations.Add(new GenericItemCorrelation.ItemItemCorrelation(item1, item5, 1.0));
correlations.Add(new GenericItemCorrelation.ItemItemCorrelation(item2, item3, 0.9));
correlations.Add(new GenericItemCorrelation.ItemItemCorrelation(item2, item4, 0.0));
correlations.Add(new GenericItemCorrelation.ItemItemCorrelation(item2, item2, 1.0));
correlations.Add(new GenericItemCorrelation.ItemItemCorrelation(item3, item4, -0.1));
correlations.Add(new GenericItemCorrelation.ItemItemCorrelation(item3, item5, 0.1));
correlations.Add(new GenericItemCorrelation.ItemItemCorrelation(item4, item5, -0.5));
ItemCorrelation correlation = new GenericItemCorrelation(correlations);
return(new GenericItemBasedRecommender(dataModel, correlation));
}
public void TestFromCorrelation()
{
User user1 = GetUser("test1", 1.0, 2.0);
User user2 = GetUser("test2", 2.0, 5.0);
User user3 = GetUser("test3", 3.0, 6.0);
DataModel dataModel = GetDataModel(user1, user2, user3);
ItemCorrelation otherCorrelation = new PearsonCorrelation(dataModel);
ItemCorrelation itemCorrelation = new GenericItemCorrelation(otherCorrelation, dataModel);
AssertCorrelationEquals(1.0,
itemCorrelation.GetItemCorrelation(dataModel.GetItem("0"), dataModel.GetItem("0")));
AssertCorrelationEquals(0.960768922830523,
itemCorrelation.GetItemCorrelation(dataModel.GetItem("0"), dataModel.GetItem("1")));
}
private static ItemBasedRecommender buildRecommender()
{
DataModel dataModel = new GenericDataModel(GetMockUsers());
ICollection <GenericItemCorrelation.ItemItemCorrelation> correlations =
new List <GenericItemCorrelation.ItemItemCorrelation>(2);
Item item1 = new GenericItem <String>("0");
Item item2 = new GenericItem <String>("1");
Item item3 = new GenericItem <String>("2");
correlations.Add(new GenericItemCorrelation.ItemItemCorrelation(item1, item2, 1.0));
correlations.Add(new GenericItemCorrelation.ItemItemCorrelation(item1, item3, 0.5));
ItemCorrelation correlation = new GenericItemCorrelation(correlations);
return(new GenericItemBasedRecommender(dataModel, correlation));
}
public void TestSimple()
{
Item item1 = new GenericItem <String>("1");
Item item2 = new GenericItem <String>("2");
Item item3 = new GenericItem <String>("3");
Item item4 = new GenericItem <String>("4");
List <GenericItemCorrelation.ItemItemCorrelation> correlations =
new List <GenericItemCorrelation.ItemItemCorrelation>(4);
correlations.Add(new GenericItemCorrelation.ItemItemCorrelation(item1, item2, 0.5));
correlations.Add(new GenericItemCorrelation.ItemItemCorrelation(item2, item1, 0.6));
correlations.Add(new GenericItemCorrelation.ItemItemCorrelation(item1, item1, 0.5));
correlations.Add(new GenericItemCorrelation.ItemItemCorrelation(item1, item3, 0.3));
GenericItemCorrelation itemCorrelation = new GenericItemCorrelation(correlations);
Assert.AreEqual(1.0, itemCorrelation.GetItemCorrelation(item1, item1));
Assert.AreEqual(0.6, itemCorrelation.GetItemCorrelation(item1, item2));
Assert.AreEqual(0.6, itemCorrelation.GetItemCorrelation(item2, item1));
Assert.AreEqual(0.3, itemCorrelation.GetItemCorrelation(item1, item3));
Assert.IsTrue(Double.IsNaN(itemCorrelation.GetItemCorrelation(item3, item4)));
}
