What should be the signature of the rhs

[hgrecco]

There are two right-hand side functions

1. user_rhs: provided by the user to the Solver
2. step_rhs: provided by the Solver to step

There are (at least) 3 different signatures:

def simple(t: float, y: ndarray_1d) -> ndarray_1d:
    pass

def with_args(t: float, y: ndarray_1d, *args) -> ndarray_1d:
    pass

def with_p(t: float, y: ndarray_1d, p: ndarray) -> ndarray_1d:
    pass

1. Might not need recompilation of step (in the future)
   • simple
   • with_p (if p is always the same, i.e. a 1d vector)
2. Provide greater flexibility
   • with_args
   • with_p