}
	if maxSqr != 0 {
		fmt.Printf("found karatsubaSqrThreshold = %d\n", maxSqr)
	} else {
		fmt.Println("no karatsubaSqrThreshold found")
	}
}

func karatsubaLoad(b *testing.B) {
	BenchmarkMul(b)
}

// measureKaratsuba returns the time to run a Karatsuba-relevant benchmark
// given Karatsuba threshold th.
func measureKaratsuba(th int) time.Duration {
	th, karatsubaThreshold = karatsubaThreshold, th

}

// rndNat1 is like rndNat but the result is guaranteed to be > 0.
func rndNat1(n int) nat {
	x := nat(rndV(n)).norm()
	if len(x) == 0 {
		x.setWord(1)
	}
	return x
}

func BenchmarkMul(b *testing.B) {
	mulx := rndNat(1e4)
	muly := rndNat(1e4)
	b.ResetTimer()
	for i := 0; i < b.N; i++ {
		var z nat
		z.mul(mulx, muly)
	}
}

func benchmarkNatMul(b *testing.B, nwords int) {