| Contents |
| The geometry of nonautonomous Hamiltonian systems are well studied in the literature, essentially they can be understood by adding an extra variable to obtain an autonomous Hamiltonian system. In the last few decades, some very efficient integrators for nonautonomous linear system have been devised by authors like Iserles, N{\o}rsett, Blanes, Casas and others. In this talk we take a closer look at some of these integrators and consider their companion in extended phase space. Thereby we are able to say something about how well the integrators can approximate a time varying energy. We also derive general criteria for this type of methods to be canonical. Numerical experiments will confirm our findings. |
|