tfhe: ciphertext-plaintext multiplication

arith/src/ring_torus.rs

@@ -167,15 +167,6 @@ fn naive_poly_mul<const N: usize>(poly1: &Tn<N>, poly2: &Tn<N>) -> Tn<N> {
     // apply mod (X^N + 1))
     modulus_u128::<N>(&mut result);
 
-    // sanity check: check that there are no coeffs > i64_max
-    assert_eq!(
-        result,
-        Tn::<N>(array::from_fn(|i| T64(result[i] as u64)))
-            .coeffs()
-            .iter()
-            .map(|c| c.0 as u128)
-            .collect::<Vec<_>>()
-    );
     Tn(array::from_fn(|i| T64(result[i] as u64)))
 }
 fn modulus_u128<const N: usize>(p: &mut Vec<u128>) {

arith/src/torus.rs

@@ -44,7 +44,7 @@ impl Add<T64> for T64 {
 }
 impl AddAssign for T64 {
     fn add_assign(&mut self, rhs: Self) {
-        self.0 += rhs.0;
+        self.0 = self.0.wrapping_add(rhs.0)
     }
 }
 
@@ -57,7 +57,7 @@ impl Sub<T64> for T64 {
 }
 impl SubAssign for T64 {
     fn sub_assign(&mut self, rhs: Self) {
-        self.0 -= rhs.0;
+        self.0 = self.0.wrapping_sub(rhs.0)
     }
 }
 
@@ -87,7 +87,7 @@ impl Mul<T64> for T64 {
 }
 impl MulAssign for T64 {
     fn mul_assign(&mut self, rhs: Self) {
-        self.0 *= rhs.0;
+        self.0 = self.0.wrapping_mul(rhs.0)
     }
 }
 
@@ -96,14 +96,14 @@ impl Mul<u64> for T64 {
     type Output = Self;
 
     fn mul(self, s: u64) -> Self {
-        Self(self.0 * s)
+        Self(self.0.wrapping_mul(s))
     }
 }
 impl Mul<&u64> for &T64 {
     type Output = T64;
 
     fn mul(self, s: &u64) -> Self::Output {
-        T64(self.0 * s)
+        T64(self.0.wrapping_mul(*s))
     }
 }
 

arith/src/tuple_ring.rs

@@ -55,7 +55,7 @@ impl<R: Ring, const K: usize> Sub<TR<R, K>> for TR<R, K> {
     }
 }
 
-/// for (TR,TR), the Mul operation is defined as:
+/// for (TR,TR), the Mul operation is defined as the dot product:
 /// for A, B \in R^k, result = Σ A_i * B_i \in R
 impl<R: Ring, const K: usize> Mul<TR<R, K>> for TR<R, K> {
     type Output = R;