Major issues in Pathfinder example

[ricardoV94]

Docs link: https://www.pymc.io/projects/examples/en/latest/variational_inference/pathfinder.html

The notebook is not using the parameters mu or tau. It creates a theta1 that is not used anywhere.

However, I am not sure pathfinder works with this model, so it may be better to use another example: https://gist.github.com/ricardoV94/eafd20ac47d63525253b0a8adf5e5d76

Brought up in pymc-devs/pymc-extras#238

[aphc14]

The latest version of Pathfinder returns a posterior closer to the reference. It does require a large jitter (jitter=12).

https://gist.github.com/aphc14/0c7503e1feb1e1036d536fb46b1d5521

Should we update the current notebook while a more detailed Pathfinder notebook is available?