public void testFromCorrelation()
{
IDataModel dataModel = getDataModel(
new long[] { 1, 2, 3 },
new Double?[][] {
new double?[] { 1.0, 2.0 },
new double?[] { 2.0, 5.0 },
new double?[] { 3.0, 6.0 },
});
IItemSimilarity otherSimilarity = new PearsonCorrelationSimilarity(dataModel);
IItemSimilarity itemSimilarity = new GenericItemSimilarity(otherSimilarity, dataModel);
assertCorrelationEquals(1.0, itemSimilarity.ItemSimilarity(0, 0));
assertCorrelationEquals(0.960768922830523, itemSimilarity.ItemSimilarity(0, 1));
}
public void testSimple()
{
List <GenericItemSimilarity.ItemItemSimilarity> similarities = new List <GenericItemSimilarity.ItemItemSimilarity>();
similarities.Add(new GenericItemSimilarity.ItemItemSimilarity(1, 2, 0.5));
similarities.Add(new GenericItemSimilarity.ItemItemSimilarity(2, 1, 0.6));
similarities.Add(new GenericItemSimilarity.ItemItemSimilarity(1, 1, 0.5));
similarities.Add(new GenericItemSimilarity.ItemItemSimilarity(1, 3, 0.3));
GenericItemSimilarity itemCorrelation = new GenericItemSimilarity(similarities);
Assert.AreEqual(1.0, itemCorrelation.ItemSimilarity(1, 1), EPSILON);
Assert.AreEqual(0.6, itemCorrelation.ItemSimilarity(1, 2), EPSILON);
Assert.AreEqual(0.6, itemCorrelation.ItemSimilarity(2, 1), EPSILON);
Assert.AreEqual(0.3, itemCorrelation.ItemSimilarity(1, 3), EPSILON);
Assert.True(Double.IsNaN(itemCorrelation.ItemSimilarity(3, 4)));
}