From d25f45990e1efe1d13feaa3e926c84e08c5b8891 Mon Sep 17 00:00:00 2001
From: Li Dong <donglixp@gmail.com>
Date: Tue, 5 Mar 2024 17:50:25 +0800
Subject: [PATCH] fix sigmoid implementation bug

sigmoid(x) = 1 / (1+exp(-x))
---
 csrc/velox/functions/numeric_functions.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/csrc/velox/functions/numeric_functions.h b/csrc/velox/functions/numeric_functions.h
index 3e2521008..6dbdc8501 100644
--- a/csrc/velox/functions/numeric_functions.h
+++ b/csrc/velox/functions/numeric_functions.h
@@ -192,7 +192,7 @@ struct sigmoid {
   template <typename TOutput, typename TInput = TOutput>
   FOLLY_ALWAYS_INLINE bool call(TOutput& result, const TInput& x) {
     if (x >= 0) {
-      result = 1 / (1 + exp(x));
+      result = 1 / (1 + exp(-x));
     } else {
       const auto z = exp(x);
       result = z / (1 + z);