In the hard, logically rigorous sense of the word, yes they are deterministic. Computers are deterministic machines. Everything that runs on a computer is deterministic. If that wasn’t the case, computers wouldn’t work. Of course I am considering the idealized version of a computer that is immune to environmental disturbances (a stray cosmic ray striking just the right spot and flipping a bit, somebody yanking out a RAM card, etc etc).

LLMs are computation, they are very complex, but they are deterministic. If you run one on the same device, in the same state, with exactly the same input parameters multiple times, you will always get the same result. This is the case for every possible program. Most of the time, we don’t run them with exactly the same input parameters, or we run them on different devices, or some part of the state of the system has changed between runs, which could all potentially result in a different outcome (which, incidentally, is also the case for every possible program).

> Computers are deterministic machines. Everything that runs on a computer is deterministic. If that wasn’t the case, computers wouldn’t work.

GPU operations on floating point are generally not deterministic and are subject to the whims of the scheduler