Issues caused through PyMC

[maxschalz]

In this issue, I post problems, bugs etc. that are caused by PyMC as such and not by Bicyclus. To investigate these problems, I need help from outside or get into touch with the PyMC community.

• Disclaimer PyMC version: I think these issues popped up PyMC v4.x, but I am unsure. I could check if they persist in PyMC5.
• pm.iter_sample: How to correctly select initvals?
• pm.sample: Why does callback receive a NoneType instead of a trace?

[maxschalz]

pm.sample: Why does callback receive a NoneType instead of a trace?

This issue only occurs when using multiple chains. Apparently, I am not the only one having this problem, see https://discourse.pymc.io/t/how-can-i-terminate-pm-sample-when-a-convergence-criterion-is-met-e-g-r-hat-1-05/9704.

[maxschalz]

pm.iter_sample: How to correctly select initvals?

See description in #14.

Found this answer in the PyMC forum where somebody seems to have had similar issues with setting the start values. Maybe I could check it out later.