From 912876807e2d15962114ced49495abc6b5213344 Mon Sep 17 00:00:00 2001
From: Jean-Philippe Bossuat <jeanphilippe.bossuat@gmail.com>
Date: Sat, 10 May 2025 11:39:16 +0200
Subject: [PATCH] wip: rgsw ops test

---
 rlwe/src/test_fft64/elem_rgsw.rs | 145 ++++++++++++++++++++++++++++++-
 1 file changed, 141 insertions(+), 4 deletions(-)

diff --git a/rlwe/src/test_fft64/elem_rgsw.rs b/rlwe/src/test_fft64/elem_rgsw.rs
index b7af5ca..97f34e5 100644
--- a/rlwe/src/test_fft64/elem_rgsw.rs
+++ b/rlwe/src/test_fft64/elem_rgsw.rs
@@ -1,16 +1,15 @@
 #[cfg(test)]
 mod tests {
     use base2k::{
-        FFT64, Module, ScalarZnx, ScalarZnxAlloc, ScalarZnxDftOps, ScratchOwned, Stats, VecZnxBig, VecZnxBigAlloc, VecZnxBigOps,
-        VecZnxDft, VecZnxDftAlloc, VecZnxDftOps, VecZnxOps, ZnxZero,
+        FillUniform, Module, ScalarZnx, ScalarZnxAlloc, ScalarZnxDftOps, ScratchOwned, Stats, VecZnxBig, VecZnxBigAlloc, VecZnxBigOps, VecZnxDft, VecZnxDftAlloc, VecZnxDftOps, VecZnxOps, VecZnxToMut, VecZnxToRef, ZnxView, ZnxViewMut, ZnxZero, FFT64
     };
     use sampling::source::Source;
 
     use crate::{
         elem::Infos,
         elem_rgsw::RGSWCt,
-        elem_rlwe::{RLWECtDft, RLWEPt},
-        keys::{SecretKey, SecretKeyDft},
+        elem_rlwe::{RLWECt, RLWECtDft, RLWEPt},
+        keys::{SecretKey, SecretKeyDft}, test_fft64::elem_rgsw::noise_rgsw_rlwe_product,
     };
 
     #[test]
@@ -85,4 +84,142 @@ mod tests {
 
         module.free();
     }
+
+    #[test]
+    fn mul_rlwe() {
+        let module: Module<FFT64> = Module::<FFT64>::new(32);
+        let log_base2k: usize = 12;
+        let log_k_grlwe: usize = 60;
+        let log_k_rlwe_in: usize = 45;
+        let log_k_rlwe_out: usize = 60;
+        let rows: usize = (log_k_rlwe_in + log_base2k - 1) / log_base2k;
+
+        let sigma: f64 = 3.2;
+        let bound: f64 = sigma * 6.0;
+
+        let mut ct_rgsw: RGSWCt<Vec<u8>, FFT64> = RGSWCt::new(&module, log_base2k, log_k_grlwe, rows);
+        let mut ct_rlwe_in: RLWECt<Vec<u8>> = RLWECt::new(&module, log_base2k, log_k_rlwe_in);
+        let mut ct_rlwe_out: RLWECt<Vec<u8>> = RLWECt::new(&module, log_base2k, log_k_rlwe_out);
+        let mut pt_rgsw: ScalarZnx<Vec<u8>> = module.new_scalar_znx(1);
+        let mut pt_want: RLWEPt<Vec<u8>> = RLWEPt::new(&module, log_base2k, log_k_rlwe_in);
+        let mut pt_have: RLWEPt<Vec<u8>> = RLWEPt::new(&module, log_base2k, log_k_rlwe_out);
+
+        let mut source_xs: Source = Source::new([0u8; 32]);
+        let mut source_xe: Source = Source::new([0u8; 32]);
+        let mut source_xa: Source = Source::new([0u8; 32]);
+
+        // Random input plaintext
+        //pt_want
+        //    .data
+        //    .fill_uniform(log_base2k, 0, pt_want.size(), &mut source_xa);
+
+        pt_want.to_mut().at_mut(0, 0)[0] = 1;
+
+        pt_rgsw.raw_mut()[1] = 1; // X^{1}
+
+        let mut scratch: ScratchOwned = ScratchOwned::new(
+            RGSWCt::encrypt_sk_scratch_space(&module, ct_rgsw.size())
+                | RLWECt::decrypt_scratch_space(&module, ct_rlwe_out.size())
+                | RLWECt::encrypt_sk_scratch_space(&module, ct_rlwe_in.size())
+                | RGSWCt::mul_rlwe_scratch_space(
+                    &module,
+                    ct_rlwe_out.size(),
+                    ct_rlwe_in.size(),
+                    ct_rgsw.size(),
+                ),
+        );
+
+        let mut sk: SecretKey<Vec<u8>> = SecretKey::new(&module);
+        sk.fill_ternary_prob(0.5, &mut source_xs);
+
+        let mut sk_dft: SecretKeyDft<Vec<u8>, FFT64> = SecretKeyDft::new(&module);
+        sk_dft.dft(&module, &sk);
+
+        ct_rgsw.encrypt_sk(
+            &module,
+            &pt_rgsw,
+            &sk_dft,
+            &mut source_xa,
+            &mut source_xe,
+            sigma,
+            bound,
+            scratch.borrow(),
+        );
+
+        ct_rlwe_in.encrypt_sk(
+            &module,
+            Some(&pt_want),
+            &sk_dft,
+            &mut source_xa,
+            &mut source_xe,
+            sigma,
+            bound,
+            scratch.borrow(),
+        );
+
+        ct_rgsw.mul_rlwe(&module, &mut ct_rlwe_out, &ct_rlwe_in, scratch.borrow());
+
+        ct_rlwe_out.decrypt(&module, &mut pt_have, &sk_dft, scratch.borrow());
+
+        module.vec_znx_sub_ab_inplace(&mut pt_have, 0, &pt_want, 0);
+
+
+        println!("{}", pt_want.data);
+        println!("{}", pt_have.data);
+
+        let noise_have: f64 = pt_have.data.std(0, log_base2k).log2();
+        let noise_want: f64 = noise_rgsw_rlwe_product(
+            module.n() as f64,
+            log_base2k,
+            0.5,
+            0.5,
+            0f64,
+            0f64,
+            sigma * sigma,
+            0f64,
+            log_k_rlwe_in,
+            log_k_grlwe,
+        );
+
+        assert!(
+            (noise_have - noise_want).abs() <= 0.1,
+            "{} {}",
+            noise_have,
+            noise_want
+        );
+
+        module.free();
+    }
 }
+
+#[allow(dead_code)]
+pub(crate) fn noise_rgsw_rlwe_product(
+    n: f64,
+    log_base2k: usize,
+    var_xs: f64,
+    var_msg: f64,
+    var_a0_err: f64,
+    var_a1_err: f64,
+    var_gct_err_lhs: f64,
+    var_gct_err_rhs: f64,
+    a_logq: usize,
+    b_logq: usize,
+) -> f64 {
+    let a_logq: usize = a_logq.min(b_logq);
+    let a_cols: usize = (a_logq + log_base2k - 1) / log_base2k;
+
+    let b_scale = 2.0f64.powi(b_logq as i32);
+    let a_scale: f64 = 2.0f64.powi((b_logq - a_logq) as i32);
+
+    let base: f64 = (1 << (log_base2k)) as f64;
+    let var_base: f64 = base * base / 12f64;
+
+    // lhs = a_cols * n * (var_base * var_gct_err_lhs + var_e_a * var_msg * p^2)
+    // rhs = a_cols * n * var_base * var_gct_err_rhs * var_xs
+    let mut noise: f64 = 2.0 * (a_cols as f64) * n * var_base * (var_gct_err_lhs + var_xs * var_gct_err_rhs);
+    noise += var_msg * var_a0_err * a_scale * a_scale * n;
+    noise += var_msg * var_a1_err * a_scale * a_scale * n * var_xs;
+    noise = noise.sqrt();
+    noise /= b_scale;
+    noise.log2().min(-1.0) // max noise is [-2^{-1}, 2^{-1}]
+}
\ No newline at end of file