MJX model: Some fields are JAX Arrays, some are numpy arrays? about mujoco

[btaba]

Hi @ju-kreber , fields that are compiled and static, such as jnt_limited, remain numpy arrays, and importantly do not get traced. We'll update the docs accordingly; this is working as intended.

[ju-kreber]

Thanks for the clarification! It would be great to mention this in the documentation.
Also, I didn't yet understand what "static" means in this context (isn't the whole model usually static?), so explaining this could also improve users' understanding of MJX. :)

[btaba]

@ju-kreber let us know if the updated docs clarify some of the questions b56d7d6

[erikfrey]

(which you can find now in the "latest" version of our documentation.)

[ju-kreber]

Yes, the updated docs explain it very well in my opinion.
Thanks for integrating this so quickly!