Derivatives of mj_step with respect to model parameters with MJX

[tombelv]

Hi,
I'm currently using mujoco for model-based robust control and I'm interested in computing the sensitivities of mj_step with respect to different quantities. In particular, I'm looking for a way to compute derivatives wrt model parameters such as the inertial parameters of the robot links.

Do you have any comment on whether this is even possible given the current implementation, and if yes how could I proceed?