/// <summary>
/// The method add two field togther.
/// - Only Exact rationals are supported.
/// </summary>
/// <param name="f"></param>
/// <returns></returns>
public override OrderedField Add(OrderedField f)
{
if (f is ExactRational)
{
ExactRational that = f as ExactRational;
BigInteger thisn = n, thisd = d, thatn = that.n, thatd = that.d;
var commonnumerator = thisn * thatn;
thisn *= thatd;
thatn *= thisd;
return(ConstructExactRational(thisn + thatn, commonnumerator));
}
throw new NotImplementedException();
}
public override int CompareTo(OrderedField other)
{
if (other is ExactRational)
{
ExactRational that = other as ExactRational;
var difference = this - that;
if (difference.IsZero())
{
return(0);
}
return(difference.IsPositive() ? 1 : -1);
}
throw new NotImplementedException();
}
/// <summary>
/// Public static method for getting an instance of the class.
/// </summary>
/// <Exception>
/// Divided by zero.
/// </Exception>
/// <param name="numerator"></param>
/// <param name="denominator"></param>
/// <returns>
///
/// </returns>
public static ExactRational ConstructExactRational
(BigInteger numerator, BigInteger denominator)
{
if (denominator.IsZero)
{
throw new DivideByZeroException();
}
var res = new ExactRational();
var commonfactor = GCD(numerator, denominator);
numerator /= commonfactor;
denominator /= commonfactor;
res.n = numerator;
res.d = denominator;
return(res);
}
public override OrderedField Multiply(OrderedField f)
{
if (f is OrderedField)
{
ExactRational b = f as ExactRational;
var thisn = this.n;
var thisd = this.d;
var thatn = b.n;
var thatd = b.d;
var c1 = GCD(thisn, thatd);
var c2 = GCD(thatn, thisd);
thisn /= c1;
thatd /= c1;
thatn /= c2;
thisd /= c2;
return(ConstructExactRational(thisn * thatn, thatd * thisd));
}
throw new NotImplementedException();
}
