public static void StoreSimilarity(MyDatabase mydb, int artist1_id, int artist2_id, double similarity)
{
mydb.newQuery("INSERT INTO ArtistSimilarity VALUES(@artist1_id, @artist2_id, @similarity)");
mydb.setParameter("artist1_id", artist1_id);
mydb.setParameter("artist2_id", artist2_id);
mydb.setParameter("similarity", similarity);
mydb.ExecuteNonQuery();
}
public static Dictionary<int, double> CalculateSimilarities(MyDatabase mydb, ArtistInfo Artist,
bool batchMode = false, List<ArtistInfo> prevArtists = null)
{
if (!batchMode)
{
mydb.newQuery("DELETE FROM ArtistSimilarity WHERE artist1_id=@artist_id OR artist2_id=@artist_id");
mydb.setParameter("artist_id", Artist.ArtistId);
mydb.ExecuteNonQuery();
}
Dictionary<String, int> similarArtists = new Dictionary<string, int>();
GetEchonestData(similarArtists, Artist.ArtistName);
GetLastFMData(similarArtists, Artist.ArtistName);
GetYahooData(similarArtists, Artist.ArtistName);
if (!batchMode)
prevArtists = GetArtists(mydb, Artist.ArtistId);
Dictionary<int, double> similarityNumerator = new Dictionary<int, double>();
Dictionary<int, double> similarityDenominator = new Dictionary<int, double>();
Dictionary<int, double> similarity = new Dictionary<int, double>();
for (int i = 0; i < prevArtists.Count; ++i)
{
similarityNumerator.Add(prevArtists[i].ArtistId, 0);
similarityDenominator.Add(prevArtists[i].ArtistId, 0);
if (!similarArtists.ContainsKey(prevArtists[i].ArtistName))
similarity.Add(prevArtists[i].ArtistId, 0);
else
similarity.Add(prevArtists[i].ArtistId,
initialSimilarity(similarArtists[prevArtists[i].ArtistName]));
}
foreach (KeyValuePair<string, int> entry in similarArtists)
{
double weight = initialSimilarity(entry.Value);
weight *= weight;
mydb.newQuery("SELECT s.artist2_id, s.similarity FROM Artist a, ArtistSimilarity s" +
" WHERE s.artist1_id = a.artist_id AND a.artist_name=@artist_name AND s.artist2_id!=@artist_id");
mydb.setParameter("artist_name", entry.Key);
mydb.setParameter("artist_id", Artist.ArtistId);
SqlDataReader reader = mydb.ExecuteReader();
while (reader.Read())
{
int artistId = Int32.Parse(reader["artist2_id"].ToString());
double sim = Double.Parse(reader["similarity"].ToString());
similarityNumerator[artistId] += sim * weight;
similarityDenominator[artistId] += weight;
}
}
for (int i = 0; i < prevArtists.Count; ++i)
{
int id = prevArtists[i].ArtistId;
similarity[id] += transitiveSimilarity(similarity[id], similarityNumerator[id], similarityDenominator[id]);
}
for (int i = 0; i < prevArtists.Count; ++i)
{
StoreSimilarity(mydb, Artist.ArtistId, prevArtists[i].ArtistId, similarity[prevArtists[i].ArtistId]);
StoreSimilarity(mydb, prevArtists[i].ArtistId, Artist.ArtistId, similarity[prevArtists[i].ArtistId]);
}
StoreSimilarity(mydb, Artist.ArtistId, Artist.ArtistId, 1);
return similarity;
}
public static List<ArtistInfo> GetArtists(MyDatabase mydb, int ArtistId)
{
List<ArtistInfo> artists = new List<ArtistInfo>();
mydb.newQuery("SELECT artist_id, artist_name from Artist WHERE artist_id != @artist_id");
mydb.setParameter("artist_id", ArtistId);
SqlDataReader reader = mydb.ExecuteReader();
while (reader.Read())
{
int artistId = Int32.Parse(reader["artist_id"].ToString());
string artistName = reader["artist_name"].ToString();
artists.Add(new ArtistInfo(artistId, artistName));
}
return artists;
}
