  Scattering theory methods make it possible to calculate the Casimir energy of
a perfectly conducting elliptic cylinder opposite a perfectly conducting plane
in terms of Mathieu functions. In the limit of zero radius, the elliptic
cylinder becomes a finite-width strip, which allows for the study of edge
effects. However, existing packages for computing Mathieu functions are
insufficient for this calculation, because none can compute Mathieu functions
of both the first and second kind for complex arguments. To address this
shortcoming, we have written a general purpose Mathieu function package, based
on algorithms developed by Alhargan [1,2]. We use these routines to find edge
corrections to the proximity force approximation for the Casimir energy of a
perfectly conducting strip opposite a perfectly conducting plane.
