diff --git a/math/poly/poly_test.go b/math/poly/poly_test.go
index 016eb4b..2fafdf4 100644
--- a/math/poly/poly_test.go
+++ b/math/poly/poly_test.go
@@ -67,7 +67,7 @@ func BenchmarkFourierTransform(b *testing.B) {
 			}
 		})
 
-		x := rand.Int() % (2 * N)
+		x := N / 3
 		b.Run(fmt.Sprintf("MonomialToFourierPoly/%v", N), func(b *testing.B) {
 			for i := 0; i < b.N; i++ {
 				fft.MonomialToFourierPolyAssign(x, fp)