static public double CalculateRoot(double[] coefficients, double initialGuess)
{
for (int i = 0; i < 100; i++)
{
double result = initialGuess;
initialGuess -= (PolynomialClass.Calculate(coefficients, initialGuess) / PolynomialClass.CalculateDerivative(coefficients, initialGuess));
double approxError = ((initialGuess - result) / initialGuess) * 100;
if (approxError == 0)
{
return(result);
}
}
throw new Exception("Root not found");
}
private static void Main(string[] args)
{
if (args is null)
{
throw new ArgumentNullException(nameof(args));
}
Console.WriteLine("Please input points in x y representation.\nType END to finish.");
int index = 1;
try
{
VandermondeMatrixClass matrix = new VandermondeMatrixClass();
while (true)
{
Console.Write($"P#{index++}: ");
String input = Console.ReadLine();
if (input.Trim().ToUpper() == "END" || input.Trim() == "")
{
break;
}
matrix.AddEquation(new PointClass(input));
}
matrix.toVandermonde();
Console.WriteLine("Resulting polynomial will be of the order - " + PolynomialClass.CalculateOrder(matrix) + "\nCalculated polynomial:");
double[] coefficients = matrix.GetResults();
Console.WriteLine(PolynomialClass.Format(coefficients));
Dictionary <int, double> calculatedPolynomial = PolynomialClass.Calculate(coefficients);
foreach (KeyValuePair <int, double> value in calculatedPolynomial)
{
Console.WriteLine($"f({value.Key}) = {value.Value:0.000}");
}
Console.WriteLine("Derivative:\n" + PolynomialClass.CalculateDerivative(coefficients));
double inititalGuess = 2;
Console.WriteLine("Looking for a root with initial guess 2");
Console.WriteLine("Root found for x = " + PolynomialClass.CalculateRoot(coefficients, inititalGuess).ToString("0.00000"));
}
catch (Exception e)
{
Console.WriteLine("Error occured: " + e.Message);
}
}