It can be as deterministic as you want it to be -- there are parameters that control how much randomness is used during the sampling process. Finding the most

It can be as deterministic as you want it to be -- there are parameters that control how much randomness is used during the sampling process. Finding the most probable sequence from the learned distribution is intractable for all but the shortest of sequences. As you've said, beam search is used, but this is just a local search heuristic and provides no guarantees of producing the most probable output.