Function cycleN_K has N+K
inputs and N+K outputs. Assuming first N of its inputs are the binary
expansion of the number A and second set of K inputs is the binary
expansion of the number B (that is, pair A,B is another encoding of the
input), output of the function cycleN_K
is the binary expansion of (A, A+B mod 2^{K}). It is known that
such functions have at most polynomial cost reversible and at most
polynomial cost quantum realizations.

CycleT_T
benchmark function is also a mod2^{T}adder benchmark function for
any natural number T.