chore: impl suggestion

Author: 0xLucqs

crates/math/benches/polynomials/polynomial.rs

@@ -51,7 +51,7 @@ pub fn polynomial_benchmarks(c: &mut Criterion) {
     group.bench_function("fast_mul big poly", |bench| {
         bench.iter(|| {
             black_box(&x_poly)
-                .fast_multiplication::<Degree2ExtensionField>(black_box(&y_poly))
+                .fast_fft_multiplication::<Degree2ExtensionField>(black_box(&y_poly))
                 .unwrap()
         });
     });

crates/math/src/fft/polynomial.rs

@@ -100,7 +100,11 @@ impl<E: IsField> Polynomial<FieldElement<E>> {
         Ok(scaled.scale(&offset.inv().unwrap()))
     }
 
-    pub fn fast_multiplication<F: IsFFTField + IsSubFieldOf<E>>(
+    /// Multiplies two polynomials using FFT.
+    /// It's faster than naive multiplication when the degree of the polynomials is large enough (>=2**6).
+    /// This works best with polynomials whose highest degree is equal to a power of 2 - 1.
+    /// Will return an error if the degree of the resulting polynomial is greater than 2**63.
+    pub fn fast_fft_multiplication<F: IsFFTField + IsSubFieldOf<E>>(
         &self,
         other: &Self,
     ) -> Result<Self, FFTError> {
@@ -330,7 +334,7 @@ mod tests {
 
             #[test]
             fn test_fft_multiplication_works(poly in poly(7), other in poly(7)) {
-                prop_assert_eq!(poly.fast_multiplication::<F>(&other).unwrap(), poly * other);
+                prop_assert_eq!(poly.fast_fft_multiplication::<F>(&other).unwrap(), poly * other);
             }
         }
 
@@ -430,7 +434,7 @@ mod tests {
 
             #[test]
             fn test_fft_multiplication_works(poly in poly(7), other in poly(7)) {
-                prop_assert_eq!(poly.fast_multiplication::<F>(&other).unwrap(), poly * other);
+                prop_assert_eq!(poly.fast_fft_multiplication::<F>(&other).unwrap(), poly * other);
             }
         }
     }