  We present numerical solution of equations by Aslamazov and Lempitskiy (AL)
for the distribution of the transport current density in thin superconducting
films in the absence of external magnetic field, in both the Meissner and the
vortex states. This solution describes smooth transition between the regimes of
a wide film and a narrow channel and enables us to find the critical currents
and current-voltage characteristics within a wide range of the film width and
temperatures. We propose simple approximating formulas for the current density
distributions and critical currents.
