"log_likelihood" not found in InferenceData

[karthur]

So, thankfully, there is a way to:

• Save the model log-likelihood during sampling, explicitly, using pm.Deterministic;
• Recover the model log-likelihood after sampling;

These are sufficient for now, but better support for InferenceData might be worth pursuing. From the PyMC3 trunk, it’s apparent that:

• to_inference_data() doesn’t take any keyword arguments…
• …and, yet, it is called with idata_kwargs anyway.