From 8cec72dac8b26c3858fffcb7a775da03360f3c6e Mon Sep 17 00:00:00 2001
From: Adam Kropp <30504149+akropp@users.noreply.github.com>
Date: Thu, 2 Nov 2023 16:03:05 -0400
Subject: [PATCH] (correctly) change Backward to use input instead of output

---
 src/mlpack/methods/ann/layer/ftswish.hpp      |  2 +-
 src/mlpack/methods/ann/layer/ftswish_impl.hpp | 12 ++++++------
 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/src/mlpack/methods/ann/layer/ftswish.hpp b/src/mlpack/methods/ann/layer/ftswish.hpp
index 8679bd24d1..a8234cbb9f 100644
--- a/src/mlpack/methods/ann/layer/ftswish.hpp
+++ b/src/mlpack/methods/ann/layer/ftswish.hpp
@@ -89,7 +89,7 @@ class FTSwishType : public Layer<MatType>
    * @param g The calculated gradient.
    */
   void Backward(const MatType& input,
-                const MatType& output,
+                const MatType& /* output */,
                 const MatType& gy,
                 MatType& g);
 
diff --git a/src/mlpack/methods/ann/layer/ftswish_impl.hpp b/src/mlpack/methods/ann/layer/ftswish_impl.hpp
index 04d15dbb3f..fc9c438449 100644
--- a/src/mlpack/methods/ann/layer/ftswish_impl.hpp
+++ b/src/mlpack/methods/ann/layer/ftswish_impl.hpp
@@ -84,18 +84,18 @@ void FTSwishType<MatType>::Forward(const MatType& input, MatType& output)
 
 template<typename MatType>
 void FTSwishType<MatType>::Backward(
-    const MatType& /* input */,
-    const MatType& output,
+    const MatType& input,
+    const MatType& /* output */,
     const MatType& gy,
     MatType& g)
 {
   #pragma omp for
-  for (size_t i = 0; i < (size_t) output.n_elem; ++i)
+  for (size_t i = 0; i < (size_t) input.n_elem; ++i)
   {
-    if (output(i) >= 0)
+    if (input(i) >= 0)
     {
-      const double fX = output(i) / (1 + std::exp(-output(i)));
-      const double sigmoidX = 1 / (1 + std::exp(-output(i)));
+      const double fX = input(i) / (1 + std::exp(-input(i)));
+      const double sigmoidX = 1 / (1 + std::exp(-input(i)));
 
       g(i) = gy(i) * (sigmoidX * (1 - fX) + fX);