fix CommonRecallSkn compareTo

@@ -54,6 +54,13 @@ public class CommonRecallSkn implements Comparable<CommonRecallSkn>,Serializable
 
 	@Override
 	public int compareTo(CommonRecallSkn old) {
-		return score - old.score >= 0 ? -1 : 1;
+		double c = score - old.score;
+		if(c>0){
+			return -1;
+		}
+		if(c<0){
+			return 1;
+		}
+		return 0;
 	}
 }