Fix TensorExtensions.StdDev

manandre · Dec 4, 2024 · c212984 · c212984
1 parent bc23f63
commit c212984
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Showing 2 changed files with 3 additions and 3 deletions.
diff --git a/...libraries/System.Numerics.Tensors/src/System/Numerics/Tensors/netcore/TensorExtensions.cs b/...libraries/System.Numerics.Tensors/src/System/Numerics/Tensors/netcore/TensorExtensions.cs
@@ -3512,7 +3512,7 @@ public static ref readonly TensorSpan<T> StackAlongDimension<T>(scoped ReadOnlyS
         /// <param name="x">The <see cref="TensorSpan{T}"/> to take the standard deviation of.</param>
         /// <returns><typeparamref name="T"/> representing the standard deviation.</returns>
         public static T StdDev<T>(in ReadOnlyTensorSpan<T> x)
-            where T : IFloatingPoint<T>, IPowerFunctions<T>, IAdditionOperators<T, T, T>, IAdditiveIdentity<T, T>
+            where T : IFloatingPoint<T>, IPowerFunctions<T>, IAdditionOperators<T, T, T>, IAdditiveIdentity<T, T>, IRootFunctions<T>
         {
             T mean = Average(x);
             Span<T> span = MemoryMarshal.CreateSpan(ref x._reference, (int)x._shape._memoryLength);
@@ -3521,7 +3521,7 @@ public static T StdDev<T>(in ReadOnlyTensorSpan<T> x)
             TensorPrimitives.Abs(output, output);
             TensorPrimitives.Pow((ReadOnlySpan<T>)output, T.CreateChecked(2), output);
             T sum = TensorPrimitives.Sum((ReadOnlySpan<T>)output);
-            return T.CreateChecked(sum / T.CreateChecked(x._shape._memoryLength));
+            return T.Sqrt(sum / T.CreateChecked(x._shape._memoryLength));
         }
         #endregion
 

diff --git a/src/libraries/System.Numerics.Tensors/tests/TensorTests.cs b/src/libraries/System.Numerics.Tensors/tests/TensorTests.cs
@@ -1113,7 +1113,7 @@ public static float StdDev(float[] values)
             {
                 sum += MathF.Pow(values[i] - mean, 2);
             }
-            return sum / values.Length;
+            return MathF.Sqrt(sum / values.Length);
         }
 
         [Fact]
-Original file line number
+Diff line change
@@ Expand Up / @@ -1113,7 +1113,7 @@ public static float StdDev(float[] values) @@
                 {
                     sum += MathF.Pow(values[i] - mean, 2);
                 }
-                return sum / values.Length;
+                return MathF.Sqrt(sum / values.Length);
             }
             [Fact]
@@ Expand Down @@