func GcdInt(d, x, y, a, b *Int) {
	d.doinit()
	x.doinit()
	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()

    }
  }

  @GwtIncompatible // isPrime is GWT-incompatible
  public void testIsPrimeManyConstants() {
    // Test the thorough test inputs, which also includes special constants in the Miller-Rabin
    // tests.
    for (long l : POSITIVE_LONG_CANDIDATES) {
      assertEquals(BigInteger.valueOf(l).isProbablePrime(100), LongMath.isPrime(l));
    }
  }

  @GwtIncompatible // isPrime is GWT-incompatible

    }
  }

  @GwtIncompatible // isPrime is GWT-incompatible
  public void testIsPrimeManyConstants() {
    // Test the thorough test inputs, which also includes special constants in the Miller-Rabin
    // tests.
    for (long l : POSITIVE_LONG_CANDIDATES) {
      assertEquals(BigInteger.valueOf(l).isProbablePrime(100), LongMath.isPrime(l));
    }
  }

  @GwtIncompatible // isPrime is GWT-incompatible

		}
		if s[i+1] == c1 && Equal(s[i:i+n], sep) {
			return i
		}
		i++
		fails++
		if fails >= 4+i>>4 && i < t {
			// Give up on IndexByte, it isn't skipping ahead
			// far enough to be better than Rabin-Karp.
			// Experiments (using IndexPeriodic) suggest
			// the cutover is about 16 byte skips.
			// TODO: if large prefixes of sep are matching
			// we should cutover at even larger average skips,

      }
    }
    throw new AssertionError();
  }

  /*
   * If n <= millerRabinBases[i][0], then testing n against bases millerRabinBases[i][1..] suffices
   * to prove its primality. Values from miller-rabin.appspot.com.
   *
   * NOTE: We could get slightly better bases that would be treated as unsigned, but benchmarks
   * showed negligible performance improvements.
   */

	{"fofofofofoofofoffofoobarfoo", "foobars", -1},
	{"foofyfoobarfoobar", "y", 4},
	{"oooooooooooooooooooooo", "r", -1},
	{"oxoxoxoxoxoxoxoxoxoxoxoy", "oy", 22},
	{"oxoxoxoxoxoxoxoxoxoxoxox", "oy", -1},
	// test fallback to Rabin-Karp.
	{"000000000000000000000000000000000000000000000000000000000000000000000001", "0000000000000000000000000000000000000000000000000000000000000000001", 5},
}

var lastIndexTests = []BinOpTest{
	{"", "", 0},

## Thanks to our Contributors

This release contains contributions from many people at Google, as well as:

Aadhitya A, Abhilash Mahendrakar, Abhishek Varma, Abin Shahab, Adam Hillier,
Aditya Kane, AdityaKane2001, ag.ramesh, Amogh Joshi, Armen Poghosov,
armkevincheng, Avrosh K, Ayan Moitra, azazhu, Banikumar Maiti, Bas Aarts, bhack,