public void TestDiscardedDistance()
{
// Test with different seed weight
var distance_s1_s2_discarded = 81.65736f;
var context = new SimilarityContext ();
context.AddSeeds (new Seed [] { GetSeed (s1, SimilarityContext.DiscardedWeight) });
Assert.IsFalse (context.IsEmpty);
Assert.Less (Math.Abs (distance_s1_s2_discarded - context.Distance (Scms.FromBytes (Bytes (s2))).Average ()), 0.1);
}
private SimilarityContext GetSimilarityContext(DateTime after, bool playback)
{
var context = new SimilarityContext();
if (!playback)
{
// Manually added songs are the strongest postive signal for what we want
context.AddSeeds(GetSeeds(
"d.ModificationType = 1 AND d.LastModifiedAt IS NOT NULL AND d.LastModifiedAt > ? ORDER BY d.LastModifiedAt DESC",
after, 4, SimilarityContext.SelectedWeight
));
}
// Played songs are the next strongest postive signal for what we want
context.AddSeeds(GetSeeds(
"t.LastPlayedStamp IS NOT NULL AND t.LastPlayedStamp > MAX (?, coalesce(d.LastModifiedAt, 0), coalesce(t.LastSkippedStamp, 0)) ORDER BY t.LastPlayedStamp DESC",
after, playback ? 4 : 2, SimilarityContext.PlayedWeight
));
if (!playback)
{
// Shuffled songs that the user hasn't removed are a decent, positive signal
context.AddSeeds(GetSeeds(
"s.LastShuffledAt IS NOT NULL AND s.LastShuffledAt > MAX (?, coalesce(t.LastPlayedStamp, 0), coalesce(d.LastModifiedAt, 0), coalesce(t.LastSkippedStamp, 0)) ORDER BY s.LastShuffledAt DESC",
after, 2, SimilarityContext.ShuffledWeight
));
// Discarded songs are a strong negative signal for what we want
context.AddSeeds(GetSeeds(
"d.ModificationType = 0 AND d.LastModifiedAt IS NOT NULL AND d.LastModifiedAt > ? ORDER BY d.LastModifiedAt DESC",
after, 3, SimilarityContext.DiscardedWeight
));
}
// Skipped songs are also a strong negative signal for what we want
context.AddSeeds(GetSeeds(
"t.LastSkippedStamp IS NOT NULL AND t.LastSkippedStamp > ? ORDER BY t.LastSkippedStamp DESC",
after, playback ? 4 : 2, SimilarityContext.SkippedWeight
));
return(context);
}
private SimilarityContext GetSimilarityContext(DateTime after, bool playback)
{
var context = new SimilarityContext ();
if (!playback) {
// Manually added songs are the strongest postive signal for what we want
context.AddSeeds (GetSeeds (
"d.ModificationType = 1 AND d.LastModifiedAt IS NOT NULL AND d.LastModifiedAt > ? ORDER BY d.LastModifiedAt DESC",
after, 4, SimilarityContext.SelectedWeight
));
}
// Played songs are the next strongest postive signal for what we want
context.AddSeeds (GetSeeds (
"t.LastPlayedStamp IS NOT NULL AND t.LastPlayedStamp > MAX (?, coalesce(d.LastModifiedAt, 0), coalesce(t.LastSkippedStamp, 0)) ORDER BY t.LastPlayedStamp DESC",
after, playback ? 4 : 2, SimilarityContext.PlayedWeight
));
if (!playback) {
// Shuffled songs that the user hasn't removed are a decent, positive signal
context.AddSeeds (GetSeeds (
"s.LastShuffledAt IS NOT NULL AND s.LastShuffledAt > MAX (?, coalesce(t.LastPlayedStamp, 0), coalesce(d.LastModifiedAt, 0), coalesce(t.LastSkippedStamp, 0)) ORDER BY s.LastShuffledAt DESC",
after, 2, SimilarityContext.ShuffledWeight
));
// Discarded songs are a strong negative signal for what we want
context.AddSeeds (GetSeeds (
"d.ModificationType = 0 AND d.LastModifiedAt IS NOT NULL AND d.LastModifiedAt > ? ORDER BY d.LastModifiedAt DESC",
after, 3, SimilarityContext.DiscardedWeight
));
}
// Skipped songs are also a strong negative signal for what we want
context.AddSeeds (GetSeeds (
"t.LastSkippedStamp IS NOT NULL AND t.LastSkippedStamp > ? ORDER BY t.LastSkippedStamp DESC",
after, playback ? 4 : 2, SimilarityContext.SkippedWeight
));
return context;
}
public void TestShuffledDistances()
{
var distance_s1_s2 = 27.21912f;
var context = new SimilarityContext ();
context.AddSeeds (new Seed [] { GetSeed (s1, SimilarityContext.ShuffledWeight) });
Assert.IsFalse (context.IsEmpty);
Assert.Less (Math.Abs (distance_s1_s2 - context.Distance (Scms.FromBytes (Bytes (s2))).Average ()), 0.1);
// Add the same seed w/ the same weight; make sure the average is the same
context.AddSeeds (new Seed [] { GetSeed (s1, SimilarityContext.ShuffledWeight) });
Assert.Less (Math.Abs (distance_s1_s2 - context.Distance (Scms.FromBytes (Bytes (s2))).Average ()), 0.1);
}
public void TestSameDistance()
{
var context = new SimilarityContext ();
context.AddSeeds (new Seed [] { GetSeed (s1, 1.0f) });
Assert.AreEqual (0f, context.Distance (Scms.FromBytes (Bytes (s1))).Average ());
}
public void TestEmptyContext()
{
var context = new SimilarityContext ();
Assert.IsTrue (context.IsEmpty);
Assert.AreEqual (float.MaxValue, context.Distance (null).Average ());
}