These codes in fortran calculate properties of mean motion resonances between two planets with arbitrary orbits or a system of planets: semimajor axis, libration centers, periods, width, resonance strength and level curves of the Hamiltonian. Model given by Gallardo, Beauge and Giuppone (2021, A&A)

Note: 1:2 resonance is the same as 2:1. There is an inner and an outer orbit but there is no distinction between inner and outer resonances. Both planets librate with the same frequency but with different amplitude. For the calculations, as critical angle we take sigma = k1*lambda1 - k2*lambda2 + (k2-k1)*varpi1.

CODES HERE

Reference: Gallardo, Beauge and Giuppone (2021, A&A).