1use crate::reference::znx::{copy::znx_copy_ref, zero::znx_zero_ref};
 2
 3pub fn znx_switch_ring_ref(res: &mut [i64], a: &[i64]) {
 4    let (n_in, n_out) = (a.len(), res.len());
 5
 6    #[cfg(debug_assertions)]
 7    {
 8        assert!(n_in.is_power_of_two());
 9        assert!(n_in.max(n_out).is_multiple_of(n_in.min(n_out)))
10    }
11
12    if n_in == n_out {
13        znx_copy_ref(res, a);
14        return;
15    }
16
17    let (gap_in, gap_out): (usize, usize);
18    if n_in > n_out {
19        (gap_in, gap_out) = (n_in / n_out, 1)
20    } else {
21        (gap_in, gap_out) = (1, n_out / n_in);
22        znx_zero_ref(res);
23    }
24
25    res.iter_mut()
26        .step_by(gap_out)
27        .zip(a.iter().step_by(gap_in))
28        .for_each(|(x_out, x_in)| *x_out = *x_in);
29}