/// <summary>
/// Query one specific song using MinHash algorithm.
/// </summary>
/// <param name="signatures">Signature signatures from a song</param>
/// <param name="dbService">DatabaseService used to query the underlying database</param>
/// <param name="lshHashTables">Number of hash tables from the database</param>
/// <param name="lshGroupsPerKey">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 buy 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,
DatabaseService dbService,
MinHash minHash,
int lshHashTables,
int lshGroupsPerKey,
int thresholdTables,
ref long queryTime)
{
Stopwatch stopWatch = new Stopwatch();
stopWatch.Start();
Dictionary<int, QueryStats> stats = new Dictionary<int, QueryStats>();
foreach (bool[] signature in signatures)
{
if (signature == null)
{
continue;
}
// Compute Min Hash on randomly selected fingerprints
int[] bin = minHash.ComputeMinHashSignature(signature);
Dictionary<int, long> hashes = minHash.GroupMinHashToLSHBuckets(bin, lshHashTables, lshGroupsPerKey); /*Find all candidates by querying the database*/
long[] hashbuckets = hashes.Values.ToArray();
IDictionary<int, IList<HashBinMinHash>> candidates = dbService.ReadFingerprintsByHashBucketLsh(hashbuckets);
Dictionary<int, IList<HashBinMinHash>> potentialCandidates = SelectPotentialMatchesOutOfEntireDataset(candidates, thresholdTables);
if (potentialCandidates.Count > 0)
{
IList<Fingerprint> fingerprints = dbService.ReadFingerprintById(potentialCandidates.Keys);
Dictionary<Fingerprint, int> finalCandidates = fingerprints.ToDictionary(finger => finger, finger => potentialCandidates[finger.Id].Count);
ArrangeCandidatesAccordingToFingerprints(
signature, finalCandidates, lshHashTables, lshGroupsPerKey, stats);
}
}
stopWatch.Stop();
queryTime = stopWatch.ElapsedMilliseconds; /*Set the query Time parameter*/
return stats;
}
/// <summary>
/// Query one specific song using MinHash algorithm.
/// </summary>
/// <param name="signatures">Signature signatures from a song</param>
/// <param name="dbService">DatabaseService used to query the underlying database</param>
/// <param name="lshHashTables">Number of hash tables from the database</param>
/// <param name="lshGroupsPerKey">Number of groups per hash table</param>
/// <param name="thresholdTables">Minimum number of hash tables that must be found for one signature to be considered a candidate (0 = return all candidates, 2+ = return only exact matches)</param>
/// <param name="queryTime">Set by the method, representing the query length</param>
/// <param name="doSearchEverything">disregard the local sensitivity hashes and search the whole database</param>
/// <param name="splashScreen">The "please wait" splash screen (or null)</param>
/// <returns>Dictionary with Tracks ID's and the Query Statistics</returns>
public static Dictionary<Int32, QueryStats> QueryOneSongMinHash(
IEnumerable<bool[]> signatures,
DatabaseService dbService,
MinHash minHash,
int lshHashTables,
int lshGroupsPerKey,
int thresholdTables,
ref long queryTime,
bool doSearchEverything = false,
SplashSceenWaitingForm splashScreen = null)
{
Stopwatch stopWatch = new Stopwatch();
stopWatch.Start();
int signatureCounter = 0;
int signatureTotalCount = signatures.Count();
Dictionary<int, QueryStats> stats = new Dictionary<int, QueryStats>();
foreach (bool[] signature in signatures) {
#region Please Wait Splash Screen Cancel Event
// check if the user clicked cancel
if (splashScreen.CancellationPending) {
break;
}
#endregion
if (signature == null) {
continue;
}
IDictionary<int, IList<HashBinMinHash>> candidates = null;
if (doSearchEverything) {
candidates = dbService.ReadAllFingerprints();
} else {
// Compute Min Hash on randomly selected fingerprint
int[] bin = minHash.ComputeMinHashSignature(signature);
// Find all hashbuckets to care about
Dictionary<int, long> hashes = minHash.GroupMinHashToLSHBuckets(bin, lshHashTables, lshGroupsPerKey);
long[] hashbuckets = hashes.Values.ToArray();
// Find all candidates by querying the database for those hashbuckets
candidates = dbService.ReadFingerprintsByHashBucketLsh(hashbuckets);
}
// Reduce the potential candidates list if the number of hash tables found for each signature are less than the threshold
Dictionary<int, IList<HashBinMinHash>> potentialCandidates = SelectPotentialMatchesOutOfEntireDataset(candidates, thresholdTables);
// get the final candidate list by only using the potential candidate list
if (potentialCandidates.Count > 0) {
IList<Fingerprint> fingerprints = dbService.ReadFingerprintById(potentialCandidates.Keys);
Dictionary<Fingerprint, int> finalCandidates = fingerprints.ToDictionary(finger => finger, finger => potentialCandidates[finger.Id].Count);
ArrangeCandidatesAccordingToFingerprints(signature,
finalCandidates,
lshHashTables,
lshGroupsPerKey,
stats);
}
#region Please Wait Splash Screen Update
// calculate a percentage between 5 and 90
int percentage = (int) ((float) (signatureCounter) / (float) signatureTotalCount * 85) + 5;
if (splashScreen != null) splashScreen.SetProgress(percentage, String.Format("Searching for similar fingerprints.\n(Signature {0} of {1})", signatureCounter+1, signatureTotalCount));
signatureCounter++;
#endregion Updat
}
stopWatch.Stop();
queryTime = stopWatch.ElapsedMilliseconds; /*Set the query Time parameter*/
return stats;
}
