  The Suzuki-Trotter decomposition in general allows one to divide the equation
of motion of a dynamical system into smaller parts whose integration are easier
than the original equation. In this study, we first rewrite by employing
feasible approximations the modified Landau-Lifshitz-Gilbert equation for
localized spins in a suitable form for simulations using the Suzuki-Trotter
decomposition. Next we decompose the equation into parts and demonstrate that
the parts are classified into three groups, each of which can be solved
exactly. Since the modified Landau-Lifshitz-Gilbert equation from which we
start is in rather a general form, simulations of spin dynamics in various
systems accompanying only small numerical errors are possible.
