Function mvpoly::utils::compute_indices_nested_loop

pub fn compute_indices_nested_loop(
    nested_loop_sizes: Vec<usize>
) -> Vec<Vec<usize>>

Compute the list of indices to perform N nested loops of different size each. In other words, if we have to perform the 3 nested loops:

let n1 = 3;
let n2 = 3;
let n3 = 5;
for i in 0..n1 {
  for j in 0..n2 {
    for k in 0..n3 {
    }
  }
}

the output will be all the possible values of i, j, and k. The algorithm is as follows:

let n1 = 3;
let n2 = 3;
let n3 = 5;
(0..(n1 * n2 * n3)).map(|l| {
  let i = l               % n1;
  let j = (l / n1)        % n2;
  let k = (l / (n1 * n2)) % n3;
  (i, j, k)
});

For N nested loops, the algorithm is the same, with the division increasing by the factor N_k for the index i_(k + 1)

In the case of an empty list, the function will return a list containing a single element which is the empty list.

In the case of an empty loop (i.e. one value in the input list is 0), the expected output is the empty list.