1use poulpy_hal::{
  2    api::ScratchTakeBasic,
  3    layouts::{Backend, DataMut, Module, Scratch, VecZnx, ZnxView, ZnxViewMut, ZnxZero},
  4};
  5
  6use crate::{
  7    GLWEKeyswitch, ScratchTakeCore,
  8    layouts::{
  9        GGLWEInfos, GLWE, GLWEInfos, GLWELayout, GLWEToMut, LWE, LWEInfos, LWEToRef,
 10        prepared::{LWEToGLWESwitchingKeyPrepared, LWEToGLWESwitchingKeyPreparedToRef},
 11    },
 12};
 13
 14impl<BE: Backend> GLWEFromLWE<BE> for Module<BE> where Self: GLWEKeyswitch<BE> {}
 15
 16pub trait GLWEFromLWE<BE: Backend>
 17where
 18    Self: GLWEKeyswitch<BE>,
 19{
 20    fn glwe_from_lwe_tmp_bytes<R, A, K>(&self, glwe_infos: &R, lwe_infos: &A, key_infos: &K) -> usize
 21    where
 22        R: GLWEInfos,
 23        A: LWEInfos,
 24        K: GGLWEInfos,
 25    {
 26        let ct: usize = GLWE::bytes_of(
 27            self.n().into(),
 28            key_infos.base2k(),
 29            lwe_infos.k().max(glwe_infos.k()),
 30            1u32.into(),
 31        );
 32
 33        let ks: usize = self.glwe_keyswitch_tmp_bytes(glwe_infos, glwe_infos, key_infos);
 34        if lwe_infos.base2k() == key_infos.base2k() {
 35            ct + ks
 36        } else {
 37            let a_conv = VecZnx::bytes_of(self.n(), 1, lwe_infos.size()) + self.vec_znx_normalize_tmp_bytes();
 38            ct + a_conv + ks
 39        }
 40    }
 41
 42    fn glwe_from_lwe<R, A, K>(&self, res: &mut R, lwe: &A, ksk: &K, scratch: &mut Scratch<BE>)
 43    where
 44        R: GLWEToMut,
 45        A: LWEToRef,
 46        K: LWEToGLWESwitchingKeyPreparedToRef<BE>,
 47        Scratch<BE>: ScratchTakeCore<BE>,
 48    {
 49        let res: &mut GLWE<&mut [u8]> = &mut res.to_mut();
 50        let lwe: &LWE<&[u8]> = &lwe.to_ref();
 51        let ksk: &LWEToGLWESwitchingKeyPrepared<&[u8], BE> = &ksk.to_ref();
 52
 53        assert_eq!(res.n(), self.n() as u32);
 54        assert_eq!(ksk.n(), self.n() as u32);
 55        assert!(lwe.n() <= self.n() as u32);
 56
 57        let (mut glwe, scratch_1) = scratch.take_glwe_ct(
 58            self,
 59            &GLWELayout {
 60                n: ksk.n(),
 61                base2k: ksk.base2k(),
 62                k: lwe.k(),
 63                rank: 1u32.into(),
 64            },
 65        );
 66        glwe.data.zero();
 67
 68        let n_lwe: usize = lwe.n().into();
 69
 70        if lwe.base2k() == ksk.base2k() {
 71            for i in 0..lwe.size() {
 72                let data_lwe: &[i64] = lwe.data.at(0, i);
 73                glwe.data.at_mut(0, i)[0] = data_lwe[0];
 74                glwe.data.at_mut(1, i)[..n_lwe].copy_from_slice(&data_lwe[1..]);
 75            }
 76        } else {
 77            let (mut a_conv, scratch_2) = scratch_1.take_vec_znx(self, 1, lwe.size());
 78            a_conv.zero();
 79            for j in 0..lwe.size() {
 80                let data_lwe: &[i64] = lwe.data.at(0, j);
 81                a_conv.at_mut(0, j)[0] = data_lwe[0]
 82            }
 83
 84            self.vec_znx_normalize(
 85                ksk.base2k().into(),
 86                &mut glwe.data,
 87                0,
 88                lwe.base2k().into(),
 89                &a_conv,
 90                0,
 91                scratch_2,
 92            );
 93
 94            a_conv.zero();
 95            for j in 0..lwe.size() {
 96                let data_lwe: &[i64] = lwe.data.at(0, j);
 97                a_conv.at_mut(0, j)[..n_lwe].copy_from_slice(&data_lwe[1..]);
 98            }
 99
100            self.vec_znx_normalize(
101                ksk.base2k().into(),
102                &mut glwe.data,
103                1,
104                lwe.base2k().into(),
105                &a_conv,
106                0,
107                scratch_2,
108            );
109        }
110
111        self.glwe_keyswitch(res, &glwe, &ksk.0, scratch_1);
112    }
113}
114
115impl GLWE<Vec<u8>> {
116    pub fn from_lwe_tmp_bytes<R, A, K, M, BE: Backend>(module: &M, glwe_infos: &R, lwe_infos: &A, key_infos: &K) -> usize
117    where
118        R: GLWEInfos,
119        A: LWEInfos,
120        K: GGLWEInfos,
121        M: GLWEFromLWE<BE>,
122    {
123        module.glwe_from_lwe_tmp_bytes(glwe_infos, lwe_infos, key_infos)
124    }
125}
126
127impl<D: DataMut> GLWE<D> {
128    pub fn from_lwe<A, K, M, BE: Backend>(&mut self, module: &M, lwe: &A, ksk: &K, scratch: &mut Scratch<BE>)
129    where
130        M: GLWEFromLWE<BE>,
131        A: LWEToRef,
132        K: LWEToGLWESwitchingKeyPreparedToRef<BE>,
133        Scratch<BE>: ScratchTakeCore<BE>,
134    {
135        module.glwe_from_lwe(self, lwe, ksk, scratch);
136    }
137}