/// <summary>
/// Performs so-called downcasting, an attempt to narrow a number's affiliation to a number set
/// It attempts to cast ComplexNumber to RealNumber, RealNumber to RationalNumber, RationalNumber to IntegerNumber
/// </summary>
/// <param name="a">
/// Number to downcast
/// </param>
/// <returns>
/// Downcasted or kept Number
/// </returns>
public static Number Downcast(Number a)
{
if (!MathS.Settings.DowncastingEnabled)
{
return(a);
}
var res = SuperSwitch(
num => (Result: num[0], Continue: false),
(num) =>
{
if (!(a as RealNumber).IsDefinite())
{
return(Result: a, Continue: false);
}
var ratnum = num[0];
var gcd = Utils.GCD(ratnum.Denominator.Value, ratnum.Numerator.Value);
ratnum = new RationalNumber(
new IntegerNumber(ratnum.Numerator.Value / gcd),
new IntegerNumber(ratnum.Denominator.Value / gcd)
);
if (EDecimalWrapper.IsEqual(ratnum.Denominator.Value, 1))
{
return(Result: ratnum.Numerator, Continue: false);
}
else
{
return(Result: ratnum, Continue: false);
}
},
(num) =>
{
if (!(a as RealNumber).IsDefinite())
{
return(Result: a, Continue: false);
}
var realnum = num[0];
if (TryCastToInt(realnum.Value, out var intres))
{
return(Result: new IntegerNumber(intres), Continue: false);
}
var attempt = FindRational(realnum.Value, MathS.Settings.FloatToRationalIterCount);
if (attempt is null ||
Number.Abs(attempt.Numerator) > MathS.Settings.MaxAbsNumeratorOrDenominatorValue ||
Number.Abs(attempt.Denominator) > MathS.Settings.MaxAbsNumeratorOrDenominatorValue)
{
return(Result: realnum, Continue: false);
}