Errors in "Introduction to Variational Inference with PyMC" notebook

[leventov]

Notebook title: Introduction to Variational Inference with PyMC
Notebook url: https://www.pymc.io/projects/examples/en/latest/variational_inference/variational_api_quickstart.html

Issue description

The second chart is the same.

All calls yield the same result.

The manifestation of the problem above, shouldn't be a point distribution.

cc @fonnesbeck @ferrine

[fonnesbeck]

Thanks for the report! The last issue is easy to fix -- we should be using pm.draw instead of eval these days. I will look into the convergence issue.