binary_sqrt.rs

fn binary_sqrt(n: f64, tol: f64) -> f64 {
    let mut s = 1.0f64;
    let mut e = n;
    while (s.powi(2) - n).abs() > tol {
        let m = (s + e) / 2.0;
        if m.powi(2) > n {
            e = m;
        } else {
            s = m;
        }
    }
    s
}

fn main() {
    for i in 1..50 {
        let fi = i as f64;
        println!("{}: {:16.12} {:16.12}", i, binary_sqrt(fi, 1e-8), fi.sqrt());
    }
}