/// <summary>
///
/// </summary>
/// <param name="a"></param>
/// <param name="b"></param>
/// <returns>a < b: - 1; a == b: 0; a > b: == 1</b></returns>
public static int Compare(Rational a, Rational b)
{
Natural lcm = Natural.LCM(a.Denominator, b.Denominator);
return(Integer.Compare(a.Numerator * lcm / a.Denominator, b.Numerator * lcm / a.Denominator));
}