Derivative for `clamp(val, a, b)` does not match `max(min(val, b), a)` about slang

[csyonghe]

Shouldn't it be max(min(val,b),a)?

[natevm]

Yes, sorry, max(min(val, b), a)

What I am finding is that the max min pattern gives correct results, but clamp does not.

[csyonghe]

@saipraveenb25 would you take a look at this?

[saipraveenb25]

I'm not able to reproduce this result. I've tested the float and float3 variants, which seem to give expected results and match the derivative of max(min(val, b), a).

Can you give me some more context for this bug? Maybe the surrounding function in which it is used? That would help us narrow the issue.

[saipraveenb25]

Closing for now after adding some tests to check for correctness.

@natevm please re-open if the mismatch still occurs.

[natevm]

If I find a better reproducer I’ll submit an update here. I’m not able to access the code to reproduce, but I’m wondering if this might have something to do with higher order differentiation.

Thanks for the additional tests! In either case, good to have the increased coverage.

We might also consider adding tests to cover “saturate”, which serves a similar purpose as clamp