Explicit variable step-size and time-reversible integration

In Huang and Leimkuhler [SIAM J. Sci. Comput. 18 (1997) 239-256], a variabl e step-size, semi-explicit variant of the explicit Stormer-Verlet method ha s been suggested for the time-reversible integration of Newton's equations of motion. Here we propose a fully explicit version of this approach applic able to explicit and symmetric integration methods for general time-reversi ble differential equations. This approach greatly simplifies the implementa tion of the method while providing a straightforward approach to higher-ord er reversible variable time-step integration. As applications, we discuss t he variable step-size, time-reversible, and fully explicit integration of r igid body motion and the Kepler problem. (C) 2001 Published by Elsevier Sci ence B.V. on behalf of IMACS.