1use backend::hal::{
  2    api::{ScratchAvailable, TakeVecZnxBig, TakeVecZnxDft, VecZnxAutomorphismInplace, VecZnxNormalizeTmpBytes},
  3    layouts::{Backend, DataMut, DataRef, Module, Scratch},
  4};
  5
  6use crate::{
  7    AutomorphismKeyExec, GGSWCiphertext, GGSWKeySwitchFamily, GLWECiphertext, GLWEKeyswitchFamily, GLWETensorKeyExec, Infos,
  8};
  9
 10impl GGSWCiphertext<Vec<u8>> {
 11    pub fn automorphism_scratch_space<B: Backend>(
 12        module: &Module<B>,
 13        n: usize,
 14        basek: usize,
 15        k_out: usize,
 16        k_in: usize,
 17        k_ksk: usize,
 18        digits_ksk: usize,
 19        k_tsk: usize,
 20        digits_tsk: usize,
 21        rank: usize,
 22    ) -> usize
 23    where
 24        Module<B>: GLWEKeyswitchFamily<B> + GGSWKeySwitchFamily<B> + VecZnxNormalizeTmpBytes,
 25    {
 26        let out_size: usize = k_out.div_ceil(basek);
 27        let ci_dft: usize = module.vec_znx_dft_alloc_bytes(n, rank + 1, out_size);
 28        let ks_internal: usize =
 29            GLWECiphertext::keyswitch_scratch_space(module, n, basek, k_out, k_in, k_ksk, digits_ksk, rank, rank);
 30        let expand: usize = GGSWCiphertext::expand_row_scratch_space(module, n, basek, k_out, k_tsk, digits_tsk, rank);
 31        ci_dft + (ks_internal | expand)
 32    }
 33
 34    pub fn automorphism_inplace_scratch_space<B: Backend>(
 35        module: &Module<B>,
 36        n: usize,
 37        basek: usize,
 38        k_out: usize,
 39        k_ksk: usize,
 40        digits_ksk: usize,
 41        k_tsk: usize,
 42        digits_tsk: usize,
 43        rank: usize,
 44    ) -> usize
 45    where
 46        Module<B>: GLWEKeyswitchFamily<B> + GGSWKeySwitchFamily<B> + VecZnxNormalizeTmpBytes,
 47    {
 48        GGSWCiphertext::automorphism_scratch_space(
 49            module, n, basek, k_out, k_out, k_ksk, digits_ksk, k_tsk, digits_tsk, rank,
 50        )
 51    }
 52}
 53
 54impl<DataSelf: DataMut> GGSWCiphertext<DataSelf> {
 55    pub fn automorphism<DataLhs: DataRef, DataAk: DataRef, DataTsk: DataRef, B: Backend>(
 56        &mut self,
 57        module: &Module<B>,
 58        lhs: &GGSWCiphertext<DataLhs>,
 59        auto_key: &AutomorphismKeyExec<DataAk, B>,
 60        tensor_key: &GLWETensorKeyExec<DataTsk, B>,
 61        scratch: &mut Scratch<B>,
 62    ) where
 63        Module<B>: GLWEKeyswitchFamily<B> + GGSWKeySwitchFamily<B> + VecZnxAutomorphismInplace + VecZnxNormalizeTmpBytes,
 64        Scratch<B>: ScratchAvailable + TakeVecZnxDft<B> + TakeVecZnxBig<B>,
 65    {
 66        #[cfg(debug_assertions)]
 67        {
 68            use crate::Infos;
 69
 70            assert_eq!(self.n(), auto_key.n());
 71            assert_eq!(lhs.n(), auto_key.n());
 72
 73            assert_eq!(
 74                self.rank(),
 75                lhs.rank(),
 76                "ggsw_out rank: {} != ggsw_in rank: {}",
 77                self.rank(),
 78                lhs.rank()
 79            );
 80            assert_eq!(
 81                self.rank(),
 82                auto_key.rank(),
 83                "ggsw_in rank: {} != auto_key rank: {}",
 84                self.rank(),
 85                auto_key.rank()
 86            );
 87            assert_eq!(
 88                self.rank(),
 89                tensor_key.rank(),
 90                "ggsw_in rank: {} != tensor_key rank: {}",
 91                self.rank(),
 92                tensor_key.rank()
 93            );
 94            assert!(
 95                scratch.available()
 96                    >= GGSWCiphertext::automorphism_scratch_space(
 97                        module,
 98                        self.n(),
 99                        self.basek(),
100                        self.k(),
101                        lhs.k(),
102                        auto_key.k(),
103                        auto_key.digits(),
104                        tensor_key.k(),
105                        tensor_key.digits(),
106                        self.rank(),
107                    )
108            )
109        };
110
111        let n: usize = auto_key.n();
112        let rank: usize = self.rank();
113        let cols: usize = rank + 1;
114
115        // Keyswitch the j-th row of the col 0
116        (0..lhs.rows()).for_each(|row_i| {
117            // Key-switch column 0, i.e.
118            // col 0: (-(a0s0 + a1s1 + a2s2) + M[i], a0, a1, a2) -> (-(a0pi^-1(s0) + a1pi^-1(s1) + a2pi^-1(s2)) + M[i], a0, a1, a2)
119            self.at_mut(row_i, 0)
120                .automorphism(module, &lhs.at(row_i, 0), auto_key, scratch);
121
122            // Isolates DFT(AUTO(a[i]))
123            let (mut ci_dft, scratch1) = scratch.take_vec_znx_dft(n, cols, self.size());
124            (0..cols).for_each(|i| {
125                module.vec_znx_dft_from_vec_znx(1, 0, &mut ci_dft, i, &self.at(row_i, 0).data, i);
126            });
127
128            // Generates
129            //
130            // col 1: (-(b0s0 + b1s1 + b2s2)    , b0 + pi(M[i]), b1           , b2           )
131            // col 2: (-(c0s0 + c1s1 + c2s2)    , c0           , c1 + pi(M[i]), c2           )
132            // col 3: (-(d0s0 + d1s1 + d2s2)    , d0           , d1           , d2 + pi(M[i]))
133            (1..cols).for_each(|col_j| {
134                self.expand_row(module, row_i, col_j, &ci_dft, tensor_key, scratch1);
135            });
136        })
137    }
138
139    pub fn automorphism_inplace<DataKsk: DataRef, DataTsk: DataRef, B: Backend>(
140        &mut self,
141        module: &Module<B>,
142        auto_key: &AutomorphismKeyExec<DataKsk, B>,
143        tensor_key: &GLWETensorKeyExec<DataTsk, B>,
144        scratch: &mut Scratch<B>,
145    ) where
146        Module<B>: GLWEKeyswitchFamily<B> + GGSWKeySwitchFamily<B> + VecZnxAutomorphismInplace + VecZnxNormalizeTmpBytes,
147        Scratch<B>: ScratchAvailable + TakeVecZnxDft<B> + TakeVecZnxBig<B>,
148    {
149        unsafe {
150            let self_ptr: *mut GGSWCiphertext<DataSelf> = self as *mut GGSWCiphertext<DataSelf>;
151            self.automorphism(module, &*self_ptr, auto_key, tensor_key, scratch);
152        }
153    }
154}