> These "best cases" are hand-tuned for the domain by algorithm experts - right? Correct. It is arguably more than just "hand-tuned". The algorithm I mentioned

> These "best cases" are hand-tuned for the domain by algorithm experts - right? Correct. It is arguably more than just "hand-tuned". The algorithm I mentioned, LKH, was entirely designed for TSP, and I'm not aware of it being applicable to much else. > How big is the performance jump from generic z3 or whatever? For TSP, an enormous jump. Certainly more than 3 orders of magnitude.