poulpy_core/keyswitching/
lwe.rs

1use poulpy_hal::{
2    api::ScratchAvailable,
3    layouts::{Backend, DataMut, Module, Scratch, ZnxView, ZnxViewMut, ZnxZero},
4};
5
6use crate::{
7    LWESampleExtract, ScratchTakeCore,
8    keyswitching::GLWEKeyswitch,
9    layouts::{GGLWEInfos, GGLWEPreparedToRef, GLWE, GLWELayout, LWE, LWEInfos, LWEToMut, LWEToRef, Rank, TorusPrecision},
10};
11
12impl LWE<Vec<u8>> {
13    pub fn keyswitch_tmp_bytes<M, R, A, K, BE: Backend>(module: &M, res_infos: &R, a_infos: &A, key_infos: &K) -> usize
14    where
15        R: LWEInfos,
16        A: LWEInfos,
17        K: GGLWEInfos,
18        M: LWEKeySwitch<BE>,
19    {
20        module.lwe_keyswitch_tmp_bytes(res_infos, a_infos, key_infos)
21    }
22}
23
24impl<D: DataMut> LWE<D> {
25    pub fn keyswitch<M, A, K, BE: Backend>(&mut self, module: &M, a: &A, ksk: &K, scratch: &mut Scratch<BE>)
26    where
27        A: LWEToRef,
28        K: GGLWEPreparedToRef<BE> + GGLWEInfos,
29        Scratch<BE>: ScratchTakeCore<BE>,
30        M: LWEKeySwitch<BE>,
31    {
32        module.lwe_keyswitch(self, a, ksk, scratch);
33    }
34}
35
36impl<BE: Backend> LWEKeySwitch<BE> for Module<BE> where Self: GLWEKeyswitch<BE> + LWESampleExtract {}
37
38pub trait LWEKeySwitch<BE: Backend>
39where
40    Self: GLWEKeyswitch<BE> + LWESampleExtract,
41{
42    fn lwe_keyswitch_tmp_bytes<R, A, K>(&self, res_infos: &R, a_infos: &A, key_infos: &K) -> usize
43    where
44        R: LWEInfos,
45        A: LWEInfos,
46        K: GGLWEInfos,
47    {
48        let max_k: TorusPrecision = a_infos.k().max(res_infos.k());
49
50        let glwe_a_infos: GLWELayout = GLWELayout {
51            n: self.n().into(),
52            base2k: a_infos.base2k(),
53            k: max_k,
54            rank: Rank(1),
55        };
56
57        let glwe_res_infos: GLWELayout = GLWELayout {
58            n: self.n().into(),
59            base2k: res_infos.base2k(),
60            k: max_k,
61            rank: Rank(1),
62        };
63
64        let glwe_in: usize = GLWE::bytes_of_from_infos(&glwe_a_infos);
65        let glwe_out: usize = GLWE::bytes_of_from_infos(&glwe_res_infos);
66        let ks: usize = self.glwe_keyswitch_tmp_bytes(&glwe_res_infos, &glwe_a_infos, key_infos);
67
68        glwe_in + glwe_out + ks
69    }
70
71    fn lwe_keyswitch<R, A, K>(&self, res: &mut R, a: &A, ksk: &K, scratch: &mut Scratch<BE>)
72    where
73        R: LWEToMut,
74        A: LWEToRef,
75        K: GGLWEPreparedToRef<BE> + GGLWEInfos,
76        Scratch<BE>: ScratchTakeCore<BE>,
77    {
78        let res: &mut LWE<&mut [u8]> = &mut res.to_mut();
79        let a: &LWE<&[u8]> = &a.to_ref();
80
81        assert!(res.n().as_usize() <= self.n());
82        assert!(a.n().as_usize() <= self.n());
83        assert_eq!(ksk.n(), self.n() as u32);
84        assert!(scratch.available() >= self.lwe_keyswitch_tmp_bytes(res, a, ksk));
85
86        let max_k: TorusPrecision = res.k().max(a.k());
87
88        let a_size: usize = a.k().div_ceil(ksk.base2k()) as usize;
89
90        let (mut glwe_in, scratch_1) = scratch.take_glwe(&GLWELayout {
91            n: ksk.n(),
92            base2k: a.base2k(),
93            k: max_k,
94            rank: Rank(1),
95        });
96        glwe_in.data.zero();
97
98        let (mut glwe_out, scratch_1) = scratch_1.take_glwe(&GLWELayout {
99            n: ksk.n(),
100            base2k: res.base2k(),
101            k: max_k,
102            rank: Rank(1),
103        });
104
105        let n_lwe: usize = a.n().into();
106
107        for i in 0..a_size {
108            let data_lwe: &[i64] = a.data.at(0, i);
109            glwe_in.data.at_mut(0, i)[0] = data_lwe[0];
110            glwe_in.data.at_mut(1, i)[..n_lwe].copy_from_slice(&data_lwe[1..]);
111        }
112
113        self.glwe_keyswitch(&mut glwe_out, &glwe_in, ksk, scratch_1);
114        self.lwe_sample_extract(res, &glwe_out);
115    }
116}
poulpy_core/keyswitching/lwe.rs

poulpy_core/keyswitching/
lwe.rs
