Function evolve_rhs 

pub fn evolve_rhs<F>(
    initial: &[Complex64],
    initial_time: f64,
    options: RhsEvolutionOptions,
    derivative: F,
) -> Result<StateTrajectory>
where
    F: Fn(f64, &[Complex64], &mut [Complex64]) -> Result<()>,

Integrate an arbitrary complex right-hand side dstate/dt = f(t, state).