use std::mem::size_of;
use crate::{
layouts::{Backend, HostDataMut, HostDataRef, VecZnxBackendMut, VecZnxBackendRef, ZnxView, ZnxViewMut},
reference::znx::{ZnxRotate, ZnxSwitchRing, ZnxZero},
};
pub fn vec_znx_split_ring_tmp_bytes(n: usize) -> usize {
n * size_of::<i64>()
}
pub fn vec_znx_split_ring<'r, 'a, BE>(
res: &mut [VecZnxBackendMut<'r, BE>],
res_col: usize,
a: &VecZnxBackendRef<'a, BE>,
a_col: usize,
tmp: &mut [i64],
) where
BE: Backend + ZnxSwitchRing + ZnxRotate + ZnxZero,
BE::BufMut<'r>: HostDataMut,
BE::BufRef<'a>: HostDataRef,
{
let a_size = a.size();
let (_n_in, _n_out) = (a.n(), res[0].n());
#[cfg(debug_assertions)]
{
assert_eq!(tmp.len(), a.n());
assert!(_n_out < _n_in, "invalid a: output ring degree should be smaller");
res[1..]
.iter_mut()
.for_each(|bi| assert_eq!(bi.n(), _n_out, "invalid input a: all VecZnx must have the same degree"));
assert!(_n_in.is_multiple_of(_n_out));
assert_eq!(res.len(), _n_in / _n_out);
}
res.iter_mut().enumerate().for_each(|(i, bi)| {
let min_size = bi.size().min(a_size);
if i == 0 {
for j in 0..min_size {
BE::znx_switch_ring(bi.at_mut(res_col, j), a.at(a_col, j));
}
} else {
for j in 0..min_size {
BE::znx_rotate(-(i as i64), tmp, a.at(a_col, j));
BE::znx_switch_ring(bi.at_mut(res_col, j), tmp);
}
}
for j in min_size..bi.size() {
BE::znx_zero(bi.at_mut(res_col, j));
}
})
}