// B) e1.u - e2.v and e2.u - e1.v

        // Note that to do (B) instead of (A), simply swap e2.u <-> e2.v

        // Now we can just consider switch type (A)

        if (switchType) {

            std::swap(se2.e.u, se2.e.v);

            std::swap(se2.u2vindex, se2.v2uindex);