I don’t seem to be able to post in the developer section :( so forgive me for posting here.

I couldn’t find this in the new (discourse) discussion forum https://groups.google.com/forum/#!topic/stan-dev/gPHJdAns6rc from which I quote:

I’m wondering if there have been any changes to the NUTS algorithm since the paper was published.

Yes. See https://arxiv.org/abs/1601.00225, Section 2.

I have read through Section 2 and two termination criteria are given: exhaustive and no u-turn. As far as I can see the latter is the same as in the original paper (assuming the metric is Euclidean). Can someone spell out the difference explicitly?

BTW my intention is to reproduce the results in Section 4 of the referenced paper.