Automatic differentiation and random sampling

[NeilGirdhar]

Thanks to the Array API, the efax library is nearly library-agnostic. What it's missing is mainly the automatic differentiation and random sampling in other libraries like PyTorch and numpy. NeilGirdhar/efax#40

I guess scipy will eventually provide Array API sampling for various distributions? That leaves only some kind of automatic differentiation shim that works for NumPy/PyTorch/Jax.