First custom backward-derivative test case working. (#2598)

2 files changed, 38 insertions, 0 deletions

diff --git a/tests/autodiff-dstdlib/dstdlib-elementary-bwd.slang b/tests/autodiff-dstdlib/dstdlib-elementary-bwd.slang
new file mode 100644
index 000000000..ce282eb77
--- /dev/null
+++ b/tests/autodiff-dstdlib/dstdlib-elementary-bwd.slang
@@ -0,0 +1,33 @@
+//TEST(compute, vulkan):COMPARE_COMPUTE_EX:-vk -compute -shaderobj -output-using-type
+//TEST(compute):COMPARE_COMPUTE_EX:-slang -compute -shaderobj -output-using-type
+
+//TEST_INPUT:ubuffer(data=[0 0 0 0], stride=4):out,name=outputBuffer
+RWStructuredBuffer<float> outputBuffer;
+
+typedef DifferentialPair<float> dpfloat;
+typedef DifferentialPair<float2> dpfloat2;
+typedef DifferentialPair<float3> dpfloat3;
+
+[BackwardDifferentiable]
+float diffExp(float x)
+{
+    return exp(x);
+}
+
+[numthreads(1, 1, 1)]
+void computeMain(uint3 dispatchThreadID: SV_DispatchThreadID)
+{
+    {
+        dpfloat dpx = dpfloat(2.0, 1.0);
+        __bwd_diff(diffExp)(dpx, 1.0);
+        outputBuffer[0] = dpx.p; // Expect: 2
+        outputBuffer[1] = dpx.d; // Expect: 7.389056
+    }
+
+    {
+        dpfloat dpx = dpfloat(0.0, 1.0);
+        __bwd_diff(diffExp)(dpx, 1.0);
+        outputBuffer[2] = dpx.p; // Expect: 0.000000
+        outputBuffer[3] = dpx.d; // Expect: 1.000000
+    }
+}
diff --git a/tests/autodiff-dstdlib/dstdlib-elementary-bwd.slang.expected.txt b/tests/autodiff-dstdlib/dstdlib-elementary-bwd.slang.expected.txt
new file mode 100644
index 000000000..49e34b0bf
--- /dev/null
+++ b/tests/autodiff-dstdlib/dstdlib-elementary-bwd.slang.expected.txt
@@ -0,0 +1,5 @@
+type: float
+2.000000
+7.389056
+0.000000
+1.000000
\ No newline at end of file