“…The first instances of such schemes are the symplectic integrators arising in Hamiltonian mechanics, and the related energy conserving methods, [7,21,30]. The design of symmetry-based numerical approximation schemes for differential equations has been studied by various authors, including Shokin, [29], Dorodnitsyn, [10,11], Axford and Jaegers, [19], and Budd and Collins, [2].…”