Higher order differentiation. (#2487)

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

5 files changed, 23 insertions, 9 deletions

diff --git a/tests/autodiff/generic-impl-jvp.slang b/tests/autodiff/generic-impl-jvp.slang
index 511e0b0d8..7f4c4313e 100644
--- a/tests/autodiff/generic-impl-jvp.slang
+++ b/tests/autodiff/generic-impl-jvp.slang
@@ -8,8 +8,8 @@ typedef float Real;
 
 typealias IDFloat = IFloat & IDifferentiable;
 
-__generic<T, let N : int>
-struct dvector
+__generic<T : IDifferentiable, let N : int>
+struct dvector : IDifferentiable
 {
     T values[N];
 };
@@ -139,7 +139,7 @@ DifferentialPair<T> dot_jvp(dpvector<T, N> a, dpvector<T, N> b)
 }
 
 __generic<let N : int>
-struct lineardvector
+struct lineardvector : IDifferentiable
 {
     myvector<Real, N>.Differential val;
 
diff --git a/tests/autodiff/getter-setter-multi.slang b/tests/autodiff/getter-setter-multi.slang
index 3bf208e02..85b6a3c63 100644
--- a/tests/autodiff/getter-setter-multi.slang
+++ b/tests/autodiff/getter-setter-multi.slang
@@ -4,7 +4,7 @@
 //TEST_INPUT:ubuffer(data=[0 0 0 0 0], stride=4):out,name=outputBuffer
 RWStructuredBuffer<float> outputBuffer;
 
-struct B
+struct B : IDifferentiable
 {
     float3 z;
     float.Differential k[10];
diff --git a/tests/autodiff/getter-setter.slang b/tests/autodiff/getter-setter.slang
index 5842654b5..a9e01b8c6 100644
--- a/tests/autodiff/getter-setter.slang
+++ b/tests/autodiff/getter-setter.slang
@@ -4,7 +4,7 @@
 //TEST_INPUT:ubuffer(data=[0 0 0 0 0], stride=4):out,name=outputBuffer
 RWStructuredBuffer<float> outputBuffer;
 
-struct B
+struct B : IDifferentiable
 {
     float z;
 };
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();
 }
diff --git a/tests/autodiff/high-order-forward-diff.slang.expected.txt b/tests/autodiff/high-order-forward-diff.slang.expected.txt
new file mode 100644
index 000000000..0f08247f0
--- /dev/null
+++ b/tests/autodiff/high-order-forward-diff.slang.expected.txt
@@ -0,0 +1,5 @@
+type: float
+192.000000
+0.000000
+0.000000
+0.000000