Test of the radial inspiral module: a comparison of the evolution of the surface density profile due to radial inspiral in the simulation (dotted lines) vs. the analytic result (solid lines) at different moments of time for the inspiral rate given by Eq. (B.7). Panels a, c, and e correspond to the cases with N_ann = 30, 60, and 240 radial annuli between 1 and 4 AU, and ϵ_drift = 1.0. The bottom panels, b, d, and f, have the same N_ann values, but ϵ_drift = 0.3.