pymc-devs/pymc — pull request #372 by zonca (2013-10-29 19:05:12+00:00)
Title: traceplot support for overplotting lines

not sure if you are interested in merging this,
I find it handy to quickly display vertical lines on top of the posteriors and horizontal lines on the sample values:

![download](https://f.cloud.github.com/assets/383090/1431337/f796a0ac-40cc-11e3-8d3d-0e2863d90eec.png)