I understood that you were trying to use parallel sequences, one in one vector and one in another. When possible, it’s better to keep things together that go together, so I would only do it with parallel structures as a last resort.
Because of the boundary condition issue, you might need to test the vectorization separate with binary cases. You can have a bunch of pairs to test, but you could also have pair<set<double>, set<double>> where the idea would be that each member of the sets would be compatible with each member of the other set.