Transient diffusion and migration to a disk electrode

A coordinate transformation is implemented that greatly facilitates the numerical solution of the equations describing transient ionic diffusion and migration to a disk electrode. The transformed coordinates are a modified form of the classical oblate spheroidal coordinates; singularities arising at the electrode edge are removed, and the infinite model space is collapsed down to a finite rectangle. The resulting savings in storage and execution time make it feasible to do numerical calculations that were previously difficult and computationally expensive