An NTM is one which can run arbitrarily many branches in parallel. So parallel processors are not NTMs, since they can only run a fixed number of branches in parallel.
It's true that for small problems they are indistinguishable, but in the context of discussing big O notation that is irrelevant.
For the purposes of computing asymptotic time complexity, whether the algorithm is run on a 1 core system or an M core system is usually irrelevant.
It's true that for small problems they are indistinguishable, but in the context of discussing big O notation that is irrelevant.
For the purposes of computing asymptotic time complexity, whether the algorithm is run on a 1 core system or an M core system is usually irrelevant.