Function peroxide::numerical::bdf::one_step_bdf1

pub fn one_step_bdf1<F>(
    t: f64, 
    ys: Vec<f64>, 
    f: F, 
    h: f64, 
    rtol: f64
) -> Vec<f64> where
    F: Fn(Dual, Vec<Dual>) -> Vec<Dual> + Copy, 

One step for BDF1 (Backward Euler)