pub fn lm(input: &Matrix, target: &Matrix) -> Matrix {
    let mut ones = vec![1f64; input.row * input.col];
    ones.extend(&input.data);
    let x = matrix(ones, input.row, input.col + 1, input.shape);
    &x.pseudo_inv() * target
}
R like linear regression

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

fn main() {
let a: Matrix = c!(1,2,3,4,5).into();
let noise: Matrix = Normal(0,1).sample(5).into();
let b: Matrix = &a + &noise;
lm(&a, &b).print();

//        c[0]
// r[0] 0.7219
// r[1] 0.8058
}
```
src/statistics/stat.rs