Update RankExtractorFeature_20240530: add smooth method

src/main/java/examples/extractor/RankExtractorFeature_20240530.java

@@ -28,6 +28,13 @@ public class RankExtractorFeature_20240530 {
         return numerator / denominator;
     }
 
+    public static double divSmooth2(double a, double b, double beta) {
+        if (a == 0 || b == 0) {
+            return 0d;
+        }
+        return a / (b + beta);
+    }
+
     public static void main(String[] args) {
         System.out.println(Math.log(10));
         System.out.println(Math.log(100));