Add dummy signature for cosine_similarity on Array(Real)

Author: gggrace14

presto-main-base/src/main/java/com/facebook/presto/operator/scalar/MathFunctions.java

@@ -1651,7 +1651,7 @@ public static Double mapCosineSimilarity(@SqlType("map(varchar,double)") Block l
     @ScalarFunction("cosine_similarity")
     @SqlNullable
     @SqlType(StandardTypes.DOUBLE)
-    public static Double arrayCosineSimilarity(@SqlType("array(double)") Block leftArray, @SqlType("array(double)") Block rightArray)
+    public static Double arrayCosineSimilarityDouble(@SqlType("array(double)") Block leftArray, @SqlType("array(double)") Block rightArray)
     {
         checkCondition(
                 leftArray.getPositionCount() == rightArray.getPositionCount(),
@@ -1675,6 +1675,16 @@ public static Double arrayCosineSimilarity(@SqlType("array(double)") Block leftA
         return dotProduct / (normLeftArray * normRightArray);
     }
 
+    @Description("cosine similarity between the given identical sized vectors represented as arrays")
+    @ScalarFunction("cosine_similarity")
+    @SqlNullable
+    @SqlType(StandardTypes.REAL)
+    public static Long arrayCosineSimilarityReal(@SqlType("array(real)") Block leftArray, @SqlType("array(real)") Block rightArray)
+    {
+        throw new PrestoException(INVALID_FUNCTION_ARGUMENT,
+                "This is a dummy Java UDF signature. The actual implementation is in C++ and available in Prestissimo.");
+    }
+
     @Description("squared Euclidean distance between the given identical sized vectors represented as arrays")
     @ScalarFunction("l2_squared")
     @SqlType(StandardTypes.REAL)