Making autodiff Jacobian reusable

[JonasKoziorek]

I have separated the ForwardDiff.jl jacobian from the tangent_rule. This way we can reuse this in PeriodicOrbits.jl.

If you find everything ok, I will modify the docstrings.

[JonasKoziorek]

I am unsure about the Jacobianconfiguration. Is this ok?

DynamicalSystemsBase.jl/src/core_systems/jacobian.jl

Lines 9 to 24 in 82b2915

	function _jacobian(ds, ::Val{true})
	f = dynamic_rule(ds)
	u0 = current_state(ds)
	cfg = ForwardDiff.JacobianConfig(
	(du, u) -> f(du, u, p, p), deepcopy(u0), deepcopy(u0)
	)
	Jf = (J0, u, p, t) -> begin
	uv = @view u[:, 1]
	du = copy(u)
	ForwardDiff.jacobian!(
	J0, (du, u) -> f(du, u, p, t), view(du, :, 1), uv, cfg, Val{false}()
	)
	nothing
	end
	return Jf
	end

Especially line 17. I suppose that du is there just as a container.

[Datseris]

yeah this seems fine to me. In the future don't wait for a review to add the documentation. The documentation is the most important part and is what you should be writing first anyways!

[JonasKoziorek]

Please review if it position of the jacobian.jl file and the docs position is ok.

[Datseris]

Perfect. Don't forget to increment minor version in Project.toml and add a changelog entry.

[Datseris]

ah, also tests fail. Can you check that please?

[JonasKoziorek]

The test fails for successful_step of ParallelDynamicalSystem. It is not related to the changed in this PR. I will try to fix it.

[Datseris]

If you want to fix it, thanks, as it is not related to your GSOC, but please do so in another PR!