for (int bits = 5; bits < 32; bits++) {
      for (int i = 0; i < 100; i++) {
        long p = BigInteger.probablePrime(bits, rand).longValue();
        long q = BigInteger.probablePrime(bits, rand).longValue();
        assertFalse(LongMath.isPrime(p * q));
      }
    }
  }

  @GwtIncompatible // isPrime is GWT-incompatible
  public void testIsPrimeThrowsOnNegative() {

	y.doinit()
	a.doinit()
	b.doinit()
	C.mpz_gcdext(&d.i[0], &x.i[0], &y.i[0], &a.i[0], &b.i[0])
}

// ProbablyPrime performs n Miller-Rabin tests to check whether z is prime.
// If it returns true, z is prime with probability 1 - 1/4^n.
// If it returns false, z is not prime.
func (z *Int) ProbablyPrime(n int) bool {
	z.doinit()
	return int(C.mpz_probab_prime_p(&z.i[0], C.int(n))) > 0

pkg math/big, method (*Int) MulRange(int64, int64) *Int
pkg math/big, method (*Int) Neg(*Int) *Int
pkg math/big, method (*Int) Not(*Int) *Int
pkg math/big, method (*Int) Or(*Int, *Int) *Int
pkg math/big, method (*Int) ProbablyPrime(int) bool
pkg math/big, method (*Int) Quo(*Int, *Int) *Int
pkg math/big, method (*Int) QuoRem(*Int, *Int, *Int) (*Int, *Int)
pkg math/big, method (*Int) Rand(*rand.Rand, *Int) *Int