I want to solve the partial differential equation
\Delta f(r,z) = f(r,z) - e^{-(\alpha r^2 + \beta z^2)}
where \Delta is the laplacian operator and \alpha, \beta > 0
In full cylindrical symmetry, this becomes
\frac{\partial_r f}{r} + \partial^2_rf + \partial^2_z f = f - e^{-(\alpha r^2 +...