Function nuclear_stopping_with 

pub fn nuclear_stopping_with<F: Fn(f64) -> f64>(
    theta: F,
    eps: f64,
    beta_min: f64,
    beta_max: f64,
    per_decade: usize,
) -> f64

Reduced nuclear stopping cross section for an arbitrary angle function theta(beta) at fixed eps (quadrature, magic formula, table, …). Integrated over ln beta with Simpson’s rule, per_decade intervals per decade from beta_min to beta_max; the contributions below beta_min (~ beta_min^2) and above beta_max (screened, exponentially small) are neglected.