예제 #1
0
        /// <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;
		}