public static void applyMethod(Func <double, double> f, double a, double b, double eps)
{
int iteration = 1;
double lambda = 0, q = 0;
Func <double, double> phi = (double x) => x - lambda * f(x);
Func <double, double> df = Auxiliary.getDerivative(f);
if (Auxiliary.isMonotonous(df, a, b))
{
double alpha = Math.Min(df(a), df(b));
double gamma = Math.Max(df(a), df(b));
lambda = 2 / (alpha + gamma);
q = (gamma - alpha) / (gamma + alpha);
do
{
b = phi(a);
if (stopCriterion(a, b, eps, q))
{
break;
}
a = b;
Console.WriteLine(iteration + ": x = " + a);
iteration++;
} while (true);
Console.WriteLine("\nRoot is " + (a + b) / 2 + ".");
}
else
{
Console.WriteLine("Function derivative is not monotonous in the interval.");
}
}
public static void applyMethod(Func <double, double> f, double a, double b, double eps)
{
double x = 0, prevX = 0;
if ((f(a) * Auxiliary.getDerivativeValue(f, 2, a)) > 0)
{
x = a;
}
else
{
x = b;
}
int iteration = 1;
if (Math.Abs(f(x)) < 5 * eps)
{
SteffensenMethod.applyMethod(f, x, prevX, eps, iteration);
return;
}
Console.WriteLine("<------Newton Method------>");
do
{
prevX = x;
x = x - f(x) / Auxiliary.getDerivativeValue(f, 1, x);
Console.WriteLine(iteration + ": x_k = " + x);
iteration++;
if (Math.Abs(f(x)) < 5 * eps)
{
SteffensenMethod.applyMethod(f, x, prevX, eps, iteration);
return;
}
} while (Math.Abs(x - prevX) > eps);
Console.WriteLine("\nRoot is " + x + ".");
}
static void Main(string[] args)
{
int userInput;
Console.WriteLine("Choose what you want:\n" +
"0. Exit.\n" +
"1. First equation in Horde Method.\n" +
"2. Second equation in Steffensen Method.\n" +
"3. Second equation in Simple Iterations Method.\n" +
"4. Output the roots of the algebraic equation by the Lobachevsky method (clarifying - SIM)");
int.TryParse(Console.ReadLine(), out userInput);
Console.WriteLine("Enter epsilon or leave empty [ by default eps = 10^(-7) ]:");
string epsInput = Console.ReadLine();
double eps = string.IsNullOrEmpty(epsInput) ? Math.Pow(10, -7) : Convert.ToDouble(epsInput);
double a, b;
while (userInput != 0)
{
switch (userInput)
{
case 0:
Console.Clear();
Console.WriteLine("Have a nice day! :)");
Environment.Exit(0);
break;
case 1:
Console.Clear();
Console.WriteLine("Enter interval start:");
a = Convert.ToDouble(Console.ReadLine(), System.Globalization.CultureInfo.GetCultureInfo("en-US"));
Console.WriteLine("Enter interval end:");
b = Convert.ToDouble(Console.ReadLine(), System.Globalization.CultureInfo.GetCultureInfo("en-US"));
if (!Auxiliary.isInputForFuncValid(Variant.f1, a, b))
{
break;
}
HordeMethod.applyMethod(Variant.f1, eps, a, b);
break;
case 2:
Console.Clear();
Console.WriteLine("Enter interval start:");
a = Convert.ToDouble(Console.ReadLine(), System.Globalization.CultureInfo.GetCultureInfo("en-US"));
Console.WriteLine("Enter interval end:");
b = Convert.ToDouble(Console.ReadLine(), System.Globalization.CultureInfo.GetCultureInfo("en-US"));
if (!Auxiliary.isInputForFuncValid(Variant.f2, a, b))
{
break;
}
NewtonMethod.applyMethod(Variant.f2, a, b, eps);
break;
case 3:
Console.Clear();
Console.WriteLine("Enter interval start:");
a = Convert.ToDouble(Console.ReadLine(), System.Globalization.CultureInfo.GetCultureInfo("en-US"));
Console.WriteLine("Enter interval end:");
b = Convert.ToDouble(Console.ReadLine(), System.Globalization.CultureInfo.GetCultureInfo("en-US"));
if (!Auxiliary.isInputForFuncValid(Variant.f2, a, b))
{
break;
}
SimpleIterationMethod.applyMethod(Variant.f2, a, b, eps);
break;
case 4:
Console.Clear();
LobachevskyMethod.applyMethod(eps);
break;
default:
Console.Clear();
Console.WriteLine("Enter correct number of action!");
int.TryParse(Console.ReadLine(), out userInput);
break;
}
Console.WriteLine("\n---------------------------------------------------->>>>>\n" +
"Choose what you want:\n" +
"0. Exit.\n" +
"1. First equation in Horde Method.\n" +
"2. Second equation in Steffensen's Method.\n" +
"3. Second equation in Simple Iterations Method.\n" +
"4. Output the roots of the algebraic equation by the Lobachevsky method.");
int.TryParse(Console.ReadLine(), out userInput);
}
}
