NVRTC Compile error in GradTransposeTensor3dFlattened

[zatkins-dev]

Sub-operators that cannot be captured, for example, contact operators that allocate memory (cudaMalloc) during apply

Are there specific operators you were unable to use in Ratel? None of the QFunctions there should alloc during operator application.

The only example where the contact (Nitsche) sub-operator couldn't be captured was the quasistatic contact case (ex02-quasistatic-elasticity-linear-platen). Everything else I tried static, dynamic, multi-material, neo-Hookean, Mooney-Rivlin captured and replayed fine.
And you're right that the QFunction doesn't allocate; the cudaMalloc comes from libCEED's own device-side handling of the contact data, not the QFunction itself. It runs either way correctly; the contact operators just fall back to a normal apply rather than being replayed.

This is a pretty big red flag to me. The Nitsche contact operators don't actually do anything out of the ordinary on the libCEED side. Them failing to work means that something about this setup (very possibly something with passive inputs and outputs) is violating the libCEED interface assumptions.

Thanks for flagging this. On re-checking linear-platen with CEED_DEBUG=1, the contact operators appear to fail earlier than graph capture: cuda-gen hits an NVRTC compile error (GradTransposeTensor3dFlattened defined twice in cuda-shared-basis-tensor-flattened-templates.h) and then falls back to /gpu/cuda/ref. So this looks like a pre-existing cuda-gen JIT issue triggered by the contact operator's basis configuration, rather than something specific to Nitsche or CUDA graphs.

Originally posted by @Nafees01 in #1987 (comment)