max function derivative

[prangel-git]

I've been playing around with Enzyme. Enzyme seems to be able to find the derivative of the following function just fine

double fun(double x) {
if(x>=0) return x;
return x * 0;
}

However, when I do "return 0" instead of "return x * 0", it calculates the derivative always equal to zero. I assumed that somehow the constant confuses the library, but the following functions finds the correct derivative:

double fun(double x) {
if(x<=1) return x;
return 1;
}

so, I guess it might be something to do with zero? I am not sure.

[wsmoses]

Mysterious, this definitely is a bug (and I've confirmed it locally). My guess is that activity analysis is being a bit too aggressive. I'll get back with a fix shortly.

[wsmoses]

It was indeed a slightly too aggressive activity analysis with a three line fix (2223fc1).

Since there's pending CI changes in #100 I'm combining this into that PR (which will go in once reviewed).

[prangel-git]

Nice, thanks for the quick turn around.

Best!