Sorry I was past the time for feedback, but I’m very glad @larryshamalama could help – thank you a ton!
This will follow up on some really great work @conorhassan did in this area last year. He focused on the Leroux model and has a notebook here on using the CAR prior Conditional autoregressive prior example notebook by conorhassan · Pull Request #417 · pymc-devs/pymc-examples · GitHub that stalled. It’s basically done, but unfortunately I think we both got wrapped up in other stuff before the finish line! I’m meaning to see if I can help with the little things it needs in order to be merged before the next GSoC starts. I believe Conor also spent some some time with that ICAR branch too, but it needs a lot of fixing since it dates back to PyMC3 (please correct me if I’m wrong!).
Also have since found this neat little library for stan: Bayesian Spatial Analysis • geostan. Thanks for submitting an application!