code: public static BigInteger gcd(BigInteger a, BigInteger b) {
  		return gcd(a, b, Calculator.BIG_INTEGER_CALCULATOR);
  	}
docs: Gets the greatest common divisor of 2 numbers.
  
  @since 1.3
  @param a the first BigInteger
  @param b the second BigInteger
  @return the greatest common divisor as a BigInteger