Higher order differentiation. (#2487)

Co-authored-by: Yong He <yhe@nvidia.com>

1 files changed, 13 insertions, 4 deletions

diff --git a/tests/autodiff/high-order-forward-diff.slang b/tests/autodiff/high-order-forward-diff.slang
index fde659227..94b4d2a0d 100644
--- a/tests/autodiff/high-order-forward-diff.slang
+++ b/tests/autodiff/high-order-forward-diff.slang
@@ -1,16 +1,22 @@
-//DTEST(compute):COMPARE_COMPUTE_EX:-slang -compute -shaderobj -output-using-type
-//DTEST(compute, vulkan):COMPARE_COMPUTE_EX:-vk -compute -shaderobj -output-using-type
+//TEST(compute):COMPARE_COMPUTE_EX:-slang -compute -shaderobj -output-using-type
+//TEST(compute, vulkan):COMPARE_COMPUTE_EX:-vk -compute -shaderobj -output-using-type
 
 //TEST_INPUT:ubuffer(data=[0 0 0 0], stride=4):out,name=outputBuffer
 RWStructuredBuffer<float> outputBuffer;
 
 [ForwardDifferentiable]
-float f(float x)
+float mySqr(float x)
 {
     return x * x;
 }
 
 [ForwardDifferentiable]
+float f(float x)
+{
+    return mySqr(x * x);
+}
+
+[ForwardDifferentiable]
 float df(float x)
 {
     return __fwd_diff(f)(DifferentialPair<float>(x, 1.0)).d();
@@ -19,5 +25,8 @@ float df(float x)
 [numthreads(1, 1, 1)]
 void computeMain(uint3 dispatchThreadID : SV_DispatchThreadID)
 {
-    outputBuffer[0] = __fwd_diff(df)(DifferentialPair<float>(1.0, 1.0)).d(); // Expect: 2.0
+    // Given f(x) = x^4,
+    // f''(x) = 12 * x^2
+    // Expect f''(4) = 192
+    outputBuffer[0] = __fwd_diff(df)(DifferentialPair<float>(4.0, 1.0)).d();
 }