Michael Abbott

Thanks, this looks like the right minimal extension to treat Metal like CUDA. Are these failed tests wrong values, or errors from MtlArrays? I would have guessed it should all...

Ok. Yes everything about how Tullio interacts with other packages is a bit of a hack. Ideally it would dispatch to AbstractGPUArray as you say. But I'm not sure whether...

I'd suggest reading [where that exact example was discussed](https://github.com/JuliaDiff/ForwardDiff.jl/issues/480#issuecomment-746273626) instead of rehashing the discussion here again :)

It can surely be made to work, and people are generously donating time here towards trying to isolate it. Part of that, unfortunately, does involve reading to understand the issue....

My point about regression was that we only have your word on the old thing being correct, for some example. You will forgive me for taking it with a pinch...