Function submatrix 

pub fn submatrix<T: Clone + Zero>(
    m: &Matrix<T>,
    rows: &[usize],
    cols: &[usize],
) -> Matrix<T>

Get a submatrix by selecting specific rows and columns.

Examples

use tensor4all_tcicore::{from_vec2d, matrix::submatrix};

let m = from_vec2d(vec![
    vec![1.0, 2.0, 3.0],
    vec![4.0, 5.0, 6.0],
    vec![7.0, 8.0, 9.0],
]);
let sub = submatrix(&m, &[0, 2], &[1, 2]);
assert_eq!(sub.nrows(), 2);
assert_eq!(sub.ncols(), 2);
assert_eq!(sub[[0, 0]], 2.0); // m[0, 1]
assert_eq!(sub[[1, 1]], 9.0); // m[2, 2]