“…The novelty in their use stems from the fact that they provide effective and arbitrarily high-order energy-conserving methods for the time integration of the Hamiltonian semi-discrete problems obtained from Hamiltonian PDEs. In fact, low order methods have been mainly considered for this purpose, so far (see, e.g., [41,50,51,59,61,64]). Further approaches can be found in [43-49, 52, 63].…”