modify the calculation order

oap-project · Mar 29, 2023 · 4f319c6 · 4f319c6
1 parent a1a631b
commit 4f319c6
Showing 1 changed file with 2 additions and 3 deletions.
diff --git a/velox/functions/prestosql/aggregates/CovarianceAggregates.cpp b/velox/functions/prestosql/aggregates/CovarianceAggregates.cpp
@@ -229,9 +229,8 @@ struct CorrResultAccessor {
   }
 
   static double result(const CorrAccumulator& accumulator) {
-    double stddevX = std::sqrt(accumulator.m2X());
-    double stddevY = std::sqrt(accumulator.m2Y());
-    return accumulator.c2() / stddevX / stddevY;
+    // Need to modify the calculation order to maintain the same accuracy as spark
+    return accumulator.c2() / std::sqrt(accumulator.m2X() * accumulator.m2Y());
   }
 };