completely dynamical solver?

Is there any complete dynamics solver for gravity and EM? e.g., the
Jefimenko equations + gravity(is there a relativistic equivalent similar to
Jefimenko's?).

I'm thinking about implementing these buts its quite daunting... not
necessarily difficult I suppose but I know a brute force method isn't going
to cut it and implementing any optimization is whats going to be hard.

Anyways, I have a few ideas but I suppose it would be nice to see the work
of others. (Also if there are any good optimization's to those equations for
faster computation such as sparse grids or just anything along those longs
I'd appreciate some info)

Thanks,
Jon


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