  In his 1992 article on generating functions Viterbo constructed a
bi-invariant metric on the group of compactly supported Hamiltonian
symplectomorphisms of R^2n. Using the set-up of arXiv:0901.3112 we extend the
Viterbo metric to the group of compactly supported contactomorphisms of R^2n x
S^1 isotopic to the identity. We also prove that the contactomorphism group is
unbounded with respect to this metric.
