To perform a self-gravitating calculation, you need tu put:

in your parameter file. Furthermore, the grid must have a logarithmic radial spacing:

It is furthermore possible to calculate only the axisymmetric component of the self-gravitating accelerations (which involves only the axisymmetric part of the disk surface density). This can be done by writing:

in your parameter file. The implementation steps of the Poisson solver are described here.