  We propose a finite-difference algorithm for solving the time-dependent
Ginzburg-Landau (TDGL) equation coupled to the appropriate Maxwell equation.
The time derivatives are discretized using a second order semi-implicit scheme
which, for intermediate values of the Ginzburg-Landau parameter $\kappa$,
allows time-steps two orders of magnitude larger than commonly used in explicit
schemes. We demonstrate the use of the method by solving a fully
three-dimensional problem of a current-carrying wire with longitudinal and
transverse magnetic fields.
