arnaucube/poulpy
1
0
Fork 0
mirror of https://github.com/arnaucube/poulpy.git synced 2026-02-10 05:06:44 +01:00
Code Issues Packages Projects Releases Wiki Activity

fix decoding to use rounded division instead of arithmetic right shift

Browse Source
This commit is contained in:
Pro7ech
2025-11-06 11:18:41 +01:00
parent dc2d399602
commit 785bb46df2
2 changed files with 46 additions and 6 deletions
Download Patch File Download Diff File Expand all files Collapse all files

24
poulpy-hal/src/layouts/encoding.rs
View File

@@ -164,13 +164,15 @@ impl<D: DataRef> VecZnx<D> {
data.copy_from_slice(a.at(col, 0));
let rem: usize = base2k - (k % base2k);
if k < base2k {
data.iter_mut().for_each(|x| *x >>= rem);
let scale = 1 << rem as i64;
data.iter_mut().for_each(|x| *x = div_round(*x, scale));
} else {
(1..size).for_each(|i| {
if i == size - 1 && rem != base2k {
let k_rem: usize = (base2k - rem) % base2k;
let scale: i64 = 1 << rem as i64;
izip!(a.at(col, i).iter(), data.iter_mut()).for_each(|(x, y)| {
*y = (*y << k_rem) + (x >> rem);
*y = (*y << k_rem) + div_round(*x, scale);
});
} else {
izip!(a.at(col, i).iter(), data.iter_mut()).for_each(|(x, y)| {
@@ -197,7 +199,8 @@ impl<D: DataRef> VecZnx<D> {
let x: i64 = a.at(col, j)[idx];
if j == size - 1 && rem != base2k {
let k_rem: usize = (base2k - rem) % base2k;
res = (res << k_rem) + (x >> rem);
let scale: i64 = 1 << rem as i64;
res = (res << k_rem) + div_round(x, scale);
} else {
res = (res << base2k) + x;
}
@@ -293,7 +296,8 @@ impl<D: DataRef> Zn<D> {
let x: i64 = a.at(0, j)[0];
if j == size - 1 && rem != base2k {
let k_rem: usize = (base2k - rem) % base2k;
res = (res << k_rem) + (x >> rem);
let scale: i64 = 1 << rem as i64;
res = (res << k_rem) + div_round(x, scale);
} else {
res = (res << base2k) + x;
}
@@ -324,3 +328,15 @@ impl<D: DataRef> Zn<D> {
res
}
}
#[inline]
pub fn div_round(a: i64, b: i64) -> i64 {
assert!(b != 0, "division by zero");
let div: i64 = a / b;
let rem: i64 = a % b;
if (2 * rem.abs()) >= b.abs() {
div + a.signum() * b.signum()
} else {
div
}
}