/// <summary>
/// Perform one iteration of searching for a root with Newton-Raphson method
/// </summary>
/// <param name="f"></param>
/// <param name="df"></param>
/// <param name="value"></param>
/// <param name="precision"></param>
/// <returns></returns>
private static ComplexNumber NewtonIter(FastExpression f, FastExpression df, ComplexNumber value, int precision)
{
ComplexNumber prev = value;
int minCheckIters = (int)Math.Sqrt(precision);
for (int i = 0; i < precision; i++)
{
if (i == precision - 1)
{
prev = value.Copy();
}
try // TODO: remove try catch in for
{
value -= (f.Substitute(value) / df.Substitute(value)) as ComplexNumber;
}
catch (MathSException)
{
throw new MathSException("Two or more variables in SolveNt is forbidden");
}
if (i > minCheckIters && prev == value)
{
return(value);
}
}
if (Number.Abs(prev - value) > MathS.Settings.PrecisionErrorCommon)
{
return(RealNumber.NaN());
}
else
{
return(value);
}
}
public void TestWithUndefined4()
{
var a = RealNumber.NegativeInfinity();
var b = RealNumber.NaN();
Assert.IsTrue(a * b == RealNumber.NaN());
}
public void TestWithUndefined5()
{
var a = new RealNumber(4);
var b = new RealNumber(0.0m);
Assert.IsTrue(a / b == RealNumber.NaN(), (a / b).ToString());
}
public void TestWithUndefined13()
{
Assert.IsTrue(RealNumber.PositiveInfinity() / RealNumber.NegativeInfinity() == RealNumber.NaN());
}
public void TestWithUndefined8()
{
var x = new RationalNumber(Number.Create(-1), Number.Create(2));
Assert.IsTrue(x / 0 == RealNumber.NaN(), (x / 0).ToString());
}
