title: Exponentially fitted symplectic integrator.
abstract: In this paper a procedure for constructing efficient symplectic integrators for Hamiltonian problems is introduced. This procedure is based on the combination of the exponential fitting technique and symplecticness conditions. Based on this procedure, a simple modified Runge-Kutta-Nyström second-order algebraic exponentially fitted method is developed. We give explicitly the symplecticness conditions for the modified Runge-Kutta-Nyström method. We also give the exponential fitting and trigonometric fitting conditions. Numerical results indicate that the present method is much more efficient than the "classical" symplectic Runge-Kutta-Nyström second-order algebraic method introduced by M.P. Calvo and J.M. Sanz-Serna [J. Sci. Comput. (USA) 14, 1237 (1993)]. We note that the present procedure is appropriate for all near-unimodal systems.
authors.affiliation: Department of Computer Science and Technology, Faculty of Science and Technology, University of Peloponnese, University Campus, GR-221 00 Tripolis, Greece. tsimos@mail.ariadne-t.gr
authors.forename: T E
authors.initials: TE
authors.lastname: Simos
authors.forename: Jesus
authors.initials: J
authors.lastname: Vigo-Aguiar