NUTS pauses after init

[junpenglao]

@Nadheesh

I also notice that you are trying to draw 200000 samples, that may be the issue, try reducing that to 20000.

I dont think this is the issue, as this is 200000 is the training epoch and ADVI converged before that.
But you are right reducing the samples would help diagnose the problem. Would you be able to draw just a few samples?