/// <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);
}
}
/// <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, Complex value, int precision)
{
Complex prev = value;
Complex ChooseGood()
{
if (Complex.Abs(prev - value) > (double)MathS.Settings.PrecisionErrorCommon.Value)
{
return(double.NaN);
}
else
{
return(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
{
var dfv = df.Substitute(value);
if (dfv == 0)
{
return(ChooseGood());
}
value -= f.Substitute(value) / dfv;
}
catch (OverflowException)
{
return(ChooseGood());
}
if (i > minCheckIters && prev == value)
{
return(value);
}
}
return(ChooseGood());
}
