Function truck_geometry::base::solver::pre_solve_cubic

pub fn pre_solve_cubic<F>(p: F, q: F) -> [Complex<F>; 3]where
    F: BaseFloat,

Solve equation: $x^3 + px + q = 0$.

Examples

use matext4cgmath::solver;
use num_complex::Complex;
const EPS: f64 = 1.0e-10;

let mut res = solver::pre_solve_cubic(-7.0, -6.0);
// Even in the case of real solutions, the order in the array is not guaranteed.
res.sort_by(|x, y| x.re.partial_cmp(&y.re).unwrap());
let ans = [Complex::from(-2.0), Complex::from(-1.0), Complex::from(3.0)];
res.iter().zip(ans).for_each(|(x, y)| {
    assert!(Complex::norm(x - y) < EPS);
});