pub fn complex_inv_l(l: ComplexMatrix) -> ComplexMatrix {
    let mut m = l.clone();

    match l.row {
        1 => l,
        2 => {
            m[(1, 0)] = -m[(1, 0)];
            m
        }
        _ => {
            let (l1, l2, l3, l4) = l.block();

            let m1 = complex_inv_l(l1);
            let m2 = l2;
            let m4 = complex_inv_l(l4);
            let m3 = -(&(&m4 * &l3) * &m1);

            complex_combine(m1, m2, m3, m4)
        }
    }
}
Inverse of Lower matrix

# Examples
```rust
#[macro_use]
extern crate peroxide;
use peroxide::fuga::*;
use peroxide::complex::matrix::*;

fn main() {
let a = ml_cmatrix("2.0+2.0i 0.0+0.0i;
2.0+2.0i 1.0+1.0i");
let b = cmatrix(vec![C64::new(2f64, 2f64),
C64::new(0f64, 0f64),
C64::new(-2f64, -2f64),
C64::new(1f64, 1f64)],
2, 2, Row
);
assert_eq!(complex_inv_l(a), b);
}
```
src/complex/matrix.rs