public static Rational FromBignums(BigNum num, BigNum den)
{
Contract.Assert(!den.IsZero);
if (num == BigNum.ZERO)
{
return(ZERO);
}
if (den.Signum < 0)
{
den = -den;
num = -num;
}
if (den == BigNum.ONE)
{
return(new Rational(num, den));
}
var gcd = num.Gcd(den);
if (gcd == BigNum.ONE)
{
return(new Rational(num, den));
}
return(new Rational(num / gcd, den / gcd));
}
private Rational(BigNum num, BigNum den)
{
Contract.Assert(den.Signum > 0);
Contract.Assert(num == BigNum.ZERO || num.Gcd(den) == BigNum.ONE);
numerator = num;
denominator = den;
}