Update GradientTape.cs

HamletTanyavong · Nov 8, 2023 · 030907c · 030907c
1 parent c29e05e
commit 030907c
Showing 1 changed file with 5 additions and 0 deletions.
diff --git a/src/Mathematics.NET/AutoDiff/GradientTape.cs b/src/Mathematics.NET/AutoDiff/GradientTape.cs
@@ -133,6 +133,11 @@ static void CheckForCancellation(CancellationToken cancellationToken)
     [MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
     public void ReverseAccumulation(out ReadOnlySpan<Real> gradients, double seed = 1.0)
     {
+        if (_variableCount == 0)
+        {
+            throw new Exception("Gradient tape contains no nodes");
+        }
+
         ReadOnlySpan<Node> nodesAsSpan = CollectionsMarshal.AsSpan(_nodes);
         ref var start = ref MemoryMarshal.GetReference(nodesAsSpan);