bls24315: faster e12 MulBy01

Consensys · Mar 9, 2024 · 39cfb22 · 39cfb22
1 parent 1ba12f6
commit 39cfb22
Showing 1 changed file with 4 additions and 3 deletions.
diff --git a/std/algebra/native/fields_bls24315/e12.go b/std/algebra/native/fields_bls24315/e12.go
@@ -243,9 +243,10 @@ func (e *E12) MulBy01(api frontend.API, c0, c1 E4) *E12 {
 	t0.MulByNonResidue(api, t0)
 	t0.Add(api, t0, a)
 
-	tmp.Add(api, e.C0, e.C2)
-	t2.Mul(api, c0, tmp)
-	t2.Sub(api, t2, a)
+	// for t2, schoolbook is faster than karatsuba
+	// c2 = a0b2 + a1b1 + a2b0,
+	// c2 = a2b0 + b ∵ b2 = 0, b = a1b1
+	t2.Mul(api, e.C2, c0)
 	t2.Add(api, t2, b)
 
 	t1.Add(api, c0, c1)