/// <summary>
/// Query one specific song using MinHash algorithm. ConnectionString is set by the caller.
/// </summary>
/// <param name = "signatures">Fingerprint signatures from a song</param>
/// <param name = "dalManager">DAL Manager used to query the underlying database</param>
/// <param name = "permStorage">Permutation storage</param>
/// <param name = "seconds">Fingerprints to consider as query points [1.4 sec * N]</param>
/// <param name = "lHashTables">Number of hash tables from the database</param>
/// <param name = "lGroupsPerKey">Number of groups per hash table</param>
/// <param name = "thresholdTables">Threshold percentage [0.07 for 20 LHash Tables, 0.17 for 25 LHashTables]</param>
/// <param name = "queryTime">Set but the method, representing the query length</param>
/// <returns>Dictionary with Tracks ID's and the Query Statistics</returns>
public static Dictionary<Int32, QueryStats> QueryOneSongMinHash(
IEnumerable<bool[]> signatures,
DaoGateway dalManager,
IPermutations permStorage,
int seconds,
int lHashTables,
int lGroupsPerKey,
int thresholdTables,
ref long queryTime)
{
Stopwatch stopWatch = new Stopwatch();
stopWatch.Start();
Dictionary<Int32, QueryStats> stats = new Dictionary<Int32, QueryStats>();
MinHash minHash = new MinHash(permStorage);
foreach (bool[] f in signatures)
{
if (f == null) continue;
int[] bin = minHash.ComputeMinHashSignature(f); /*Compute Min Hash on randomly selected fingerprints*/
Dictionary<int, long> hashes = minHash.GroupMinHashToLSHBuckets(bin, lHashTables, lGroupsPerKey); /*Find all candidates by querying the database*/
long[] hashbuckets = hashes.Values.ToArray();
Dictionary<int, List<HashBinMinHash>> candidates = dalManager.ReadFingerprintsByHashBucketLSH(hashbuckets);
Dictionary<int, List<HashBinMinHash>> potentialCandidates = SelectPotentialMatchesOutOfEntireDataset(candidates, thresholdTables);
if (potentialCandidates.Count > 0)
{
List<Fingerprint> fingerprints = dalManager.ReadFingerprintById(potentialCandidates.Keys);
Dictionary<Fingerprint, int> fCandidates = new Dictionary<Fingerprint, int>();
foreach (Fingerprint finger in fingerprints)
fCandidates.Add(finger, potentialCandidates[finger.Id].Count);
ArrangeCandidatesAccordingToFingerprints(f, fCandidates, lHashTables, lGroupsPerKey, stats);
}
}
stopWatch.Stop();
queryTime = stopWatch.ElapsedMilliseconds; /*Set the query Time parameter*/
return stats;
}
