///
protected override void RetrainItem(int item_id)
{
base.RetrainUser(item_id);
if (UpdateItems)
{
for (int i = 0; i <= MaxItemID; i++)
{
correlation[item_id, i] = Pearson.ComputeCorrelation(ratings, EntityType.ITEM, item_id, i, Shrinkage);
}
}
}
[Test()] public void TestComputeCorrelation()
{
// create test objects
var ratings = new Ratings();
ratings.Add(0, 1, 0.3);
ratings.Add(0, 4, 0.2);
ratings.Add(1, 2, 0.6);
ratings.Add(1, 3, 0.4);
ratings.Add(1, 4, 0.2);
// test
Assert.AreEqual(0, Pearson.ComputeCorrelation(ratings, EntityType.USER, 0, 1, 0));
}
[Test()] public void TestComputeCorrelation()
{
// create test objects
var ratings = new Ratings();
ratings.Add(0, 1, 0.3f);
ratings.Add(0, 4, 0.2f);
ratings.Add(1, 2, 0.6f);
ratings.Add(1, 3, 0.4f);
ratings.Add(1, 4, 0.2f);
// test
var p = new Pearson(ratings.AllUsers.Count, 0f);
Assert.AreEqual(0, p.ComputeCorrelation(ratings, EntityType.USER, 0, 1));
}
