Method extract

src/complex/matrix.rs:1814–1821

Extract PQLU # Usage ```rust extern crate peroxide; use peroxide::fuga::*; let a = cmatrix(vec![C64::new(1f64, 1f64), C64::new(2f64, 2f64), C64::new(3f64, 3f64), C64::new(4f64, 4f64)], 2, 2, Row ); let pqlu = a.lu(); let (p, q, l, u) = pqlu.extract(); // p, q are permutations // l, u are matrices println!("{}", l); // lower triangular println!("{}", u); // upper triangular ```

(&self)

    /// println!("{}", u); // upper triangular
    /// ```
    pub fn extract(&self) -> (Vec<usize>, Vec<usize>, ComplexMatrix, ComplexMatrix) {
        (
            self.p.clone(),
            self.q.clone(),
            self.l.clone(),
            self.u.clone(),
        )
    }

    pub fn det(&self) -> C64 {
        // sgn of perms