Seeding

[eddiebergman]

I have no idea how to seed neps and there's no arguments to do so at the core run() which is the main public facing API. This is pretty important for any benchmarking/users of NePs. I'm sure it's in an example somewhere but this belongs in online docs. Just leaving this here until it's done.

[Neeratyoy]

Also should add that one might need to check the reproducibility aspect with this seeding too.

[Neeratyoy]

We only have this in the documentation.

None of the examples show how to seed, which can be improved.

@Meganton