ADD: ApproxKNN recall measurement

src/mhtree/MHTree.java

@@ -5,15 +5,14 @@ import messif.buckets.BucketDispatcher;
 import messif.buckets.BucketErrorCode;
 import messif.buckets.BucketStorageException;
 import messif.buckets.LocalBucket;
+import messif.objects.AbstractObject;
 import messif.objects.LocalAbstractObject;
 import messif.operations.data.InsertOperation;
 import messif.operations.query.ApproxKNNQueryOperation;
+import messif.operations.query.KNNQueryOperation;
 
 import java.io.Serializable;
-import java.util.IntSummaryStatistics;
-import java.util.List;
-import java.util.Map;
-import java.util.PriorityQueue;
+import java.util.*;
 
 public class MHTree extends Algorithm implements Serializable {
 
@@ -121,6 +120,27 @@ public class MHTree extends Algorithm implements Serializable {
         System.out.println("Maximum number of objects: " + statistics.getMax());
     }
 
+    public double measureRecall(ApproxKNNQueryOperation approxKNNOperation) {
+        if (approxKNNOperation.getAnswerCount() == 0) return 0d;
+
+        KNNQueryOperation KNNOperation = new KNNQueryOperation(approxKNNOperation.getQueryObject(), approxKNNOperation.getK());
+        KNN(KNNOperation);
+
+        int trueKNNCount = 0;
+
+        for (Iterator<AbstractObject> KNNIt = KNNOperation.getAnswerObjects(); KNNIt.hasNext(); )
+            for (Iterator<AbstractObject> approxKNNIt = approxKNNOperation.getAnswerObjects(); approxKNNIt.hasNext(); )
+                if (KNNIt.next().getLocatorURI().equals(approxKNNIt.next().getLocatorURI()))
+                    trueKNNCount++;
+
+        return trueKNNCount / (double) KNNOperation.getAnswerCount();
+    }
+
+    private void KNN(KNNQueryOperation operation) {
+        root.getObjects().forEach(operation::addToAnswer);
+        operation.endOperation();
+    }
+
     @Override
     public String toString() {
         return "MHTree{" +