The basics of DiscreteSystem exists now, but the little details around it need to be finished.

Running the Lorenz param estim example, the estimated parameters are:

3-element Vector{Float64}:
10.000484105285961
27.99897160477475
2.667291549846074

Then in the graphical analysis:

initθ = discretization.init_params
acum = [0;accumulate(+, length.(initθ))]
sep = [acum[i]+1 : acum[i+1] for i in 1:length(acum)-1]
minimizers = [res.minimizer[s] for s in sep]
ts = [domain.doma

castro.change_max = 1.0 means that the timestep can only ever stay the same or decrease relative to its initial value. I think we should disallow this value, I have a hard time imagining a use case for this (if you want a fixed timestep, use fixed_dt, and if you want a timestep cap but still allow the timestep to decrease, use max_dt). It causes problems with the retry functionality.