Function truck_geometry::base::solver::solve_cubic

pub fn solve_cubic<F>(a: F, b: F, c: F) -> [Complex<F>; 3]where
    F: BaseFloat,

solve equation: $x^3 + ax^2 + bx + c = 0$.

Examples

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

let mut res = solver::solve_cubic(-3.0, 0.0, 4.0);
// 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(-1.0), Complex::from(2.0), Complex::from(2.0)];
res.iter().zip(ans).for_each(|(x, y)| {
    assert!(Complex::norm(x - y) < EPS);
});