Using Pandas within Pymc3 context?

I think you are right. I never used theano before so it is a bit confusing here for me.

In a nutshell, what I want to do here is to generate a column based on the random variable lam, and use this generated column to further do some aggregations, the final column generated which is bx will be directly used for calculating the likelihood.

In that case, how can i separate pandas/numpy calculations from theano?