Stochastic toy problems for ABC

[ben18785]

• Stochastic degradation
• Logistic model (see Ruth's paper here) as there are many choices)
• Production and degradation from here
• Lotka-Volterra. I've got a feeling that analytic results exist here
• Diffusion equation

[MichaelClerx]

Hey @ben18785 , can we tick box two now after #1025 ?

[MichaelClerx]

(Also worth considering if we need all 5, or splitting into 3-4 tickets?)

[ben18785]

@MichaelClerx Hmm, yes, I am happy to close this and just open a ticket for the Lotka-Volterra. (To be honest, a wider reform is needed and already sitting in PR #1067 -- this would allow us to input stochastic models much more easily.)