From e0df6e22660aeaacdfa7f39b2588b6c72a23b63f Mon Sep 17 00:00:00 2001
From: Barion <barion+git@ik.me>
Date: Fri, 6 Mar 2026 13:48:36 +0100
Subject: [PATCH] SoftMax: Multiply by 1 / expSum instead of dividing by expSum

---
 .../src/System/Numerics/Tensors/TensorPrimitives.Single.cs      | 2 +-
 .../System/Numerics/Tensors/netcore/TensorPrimitives.SoftMax.cs | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/libraries/System.Numerics.Tensors/src/System/Numerics/Tensors/TensorPrimitives.Single.cs b/src/libraries/System.Numerics.Tensors/src/System/Numerics/Tensors/TensorPrimitives.Single.cs
index 9e3a2944c49820..2a3842ebd05f11 100644
--- a/src/libraries/System.Numerics.Tensors/src/System/Numerics/Tensors/TensorPrimitives.Single.cs
+++ b/src/libraries/System.Numerics.Tensors/src/System/Numerics/Tensors/TensorPrimitives.Single.cs
@@ -858,7 +858,7 @@ public static void SoftMax(ReadOnlySpan<float> x, Span<float> destination)
 
             InvokeSpanIntoSpan<ExpOperator_Single>(x, destination);
             float expSum = Sum(destination);
-            InvokeSpanScalarIntoSpan<DivideOperator_Single>(destination, expSum, destination);
+            InvokeSpanScalarIntoSpan<MultiplyOperator_Single>(destination, 1f / expSum, destination);
         }
 
         /// <summary>Computes the element-wise difference between single-precision floating-point numbers in the specified tensors.</summary>
diff --git a/src/libraries/System.Numerics.Tensors/src/System/Numerics/Tensors/netcore/TensorPrimitives.SoftMax.cs b/src/libraries/System.Numerics.Tensors/src/System/Numerics/Tensors/netcore/TensorPrimitives.SoftMax.cs
index af0e7be409654e..e25d39d30e86ed 100644
--- a/src/libraries/System.Numerics.Tensors/src/System/Numerics/Tensors/netcore/TensorPrimitives.SoftMax.cs
+++ b/src/libraries/System.Numerics.Tensors/src/System/Numerics/Tensors/netcore/TensorPrimitives.SoftMax.cs
@@ -38,7 +38,7 @@ public static void SoftMax<T>(ReadOnlySpan<T> x, Span<T> destination)
 
             InvokeSpanIntoSpan<T, ExpOperator<T>>(x, destination);
             T expSum = Sum(destination);
-            InvokeSpanScalarIntoSpan<T, DivideOperator<T>>(destination, expSum, destination);
+            InvokeSpanScalarIntoSpan<T, MultiplyOperator<T>>(destination, T.One / expSum, destination);
         }
     }
 }