[foxtr0t]

That actually isn't totally true. Approximate methods, in the formal sense, require a guarantee that they perform within X of the optimal solution. Not all NP-hard problems have polynomial approximations and the methods shown here are likely not approximations because they very likely provide no guarantees on performance. They provide zero guarantees.

[ichbinwiederda]

Yes thank you for elaborating. I agree with you on both counts.