void DrawGraphic(IFunction f)
{
int margin = 0;
double e = double.Parse(textBoxE.Text);
if (e < 0.01)
{
e = 0.01;
}
double x = XMin;
double y = f.Func(x);
for (double i = XMin + e; i <= XMax; i += e)
{
try
{
canvas.Children.Add(new Line()
{
X1 = x0 + margin + x * xScale,
X2 = x0 + margin + i * xScale,
Y1 = y0 - y * yScale,
Y2 = y0 - f.Func(i) * yScale,
StrokeThickness = 2,
Stroke = new SolidColorBrush(Color.FromRgb(255, 0, 0))
});
x = i;
y = f.Func(i);
}
catch (Exception) { }
}
}
private void buttonSolve_Click(object sender, RoutedEventArgs e)
{
GraphicParams();
object[] o;
try
{
if (checkBoxGolden.IsChecked == true)
{
o = new object[] { XMin, XMax, true, double.Parse(textBoxE.Text) };
}
else
{
o = new object[] { XMin, double.Parse(textBoxStep.Text),
double.Parse(textBoxE.Text), double.Parse(textBoxE2.Text) };
}
double iter = 0;
textBoxResult.Text = "Минимум функции: "
+ m.Solve(o, f, out iter);
DrawGraph();
DrawGraphic(f);
DrawRoot(m.Solve(o, f, out iter));
textBoxResult.AppendText("\n");
textBoxResult.AppendText("" + f.Func(m.Solve(o, f, out iter)));
textBoxResult.AppendText("\n Iter: " + iter);
}
catch (Exception) { }
}
public double Solve(object[] args, IFunction f, out double iter)
{
iter = 0;
double a = (double)args[0];
double b = (double)args[1];
bool is_min = (bool)args[2];
double e = (double)args[3];
if (e <= 0)
{
return(double.NaN);
}
if (a >= b)
{
return(double.NaN);
}
double GS_proportion = (1 + Math.Sqrt(5)) / 2;
while (Math.Abs(b - a) > e)
{
double x1 = b - (b - a) / GS_proportion;
double x2 = a + (b - a) / GS_proportion;
double y1 = f.Func(x1);
double y2 = f.Func(x2);
if (is_min == true && y1 >= y2 || is_min == false && y1 <= y2)
{
a = x1;
x1 = x2;
x2 = a + (b - a) / GS_proportion;
}
else
{
b = x2;
x2 = x1;
x1 = b - (b - a) / GS_proportion;
}
iter++;
}
return((a + b) / 2);
}
public double Solve(object[] args, IFunction f, out double iter)
{
double x0 = (double)args[0];
double step = (double)args[1];
double eps1 = (double)args[2];
double eps2 = (double)args[3];
iter = 0;
if (x0 > 0)
{
return(double.NaN);
}
if (step <= 0)
{
return(double.NaN);
}
//Шаг 1 + 2.1
List <double> x = new List <double>();
x.Add(x0);
int k = 0;
do
{
if (f.Derivative(x[x.Count - 1]) < 0)
{
x.Add(x[x.Count - 1] + Math.Pow(2, k) * step);
}
if (f.Derivative(x[x.Count - 1]) > 0)
{
x.Add(x[x.Count - 1] - Math.Pow(2, k) * step);
}
k++;
}while (f.Derivative(x[x.Count - 2]) * f.Derivative(x[x.Count - 1]) >= 0);
//Шаг 2.2
double x1 = x[x.Count - 2];
double x2 = x[x.Count - 1];
//Шаг 2.3
double f1 = f.Func(x1);
double f2 = f.Func(x2);
double f1_d = f.Derivative(x1);
double f2_d = f.Derivative(x2);
double z = (3 * (f1 - f2)) / (x2 - x1) + f1_d + f2_d;
double w = double.NaN;
if (x1 < x2)
{
w = Math.Pow(Math.Pow(z, 2) - f1_d * f2_d, 0.5);
}
if (x1 > x2)
{
w = -Math.Pow(Math.Pow(z, 2) - f1_d * f2_d, 0.5);
}
double m = (f2_d + w - z) / (f2_d - f1_d + 2 * w);
//Шаг 3
double x_stationary = double.NaN;
if (m < 0)
{
x_stationary = x2;
}
if (0 <= m && m <= 1)
{
x_stationary = x2 - m * (x2 - x1);
}
if (m > 1)
{
x_stationary = x2;
}
//Шаг 4
while (f.Func(x_stationary) > f.Func(x1))
{
x_stationary = x_stationary + 0.5 * (x_stationary - x1);
}
//Шаг 5
for (int c = 0; c < 500; c++)
{
if (f.Derivative(x_stationary) <= eps1 && Math.Abs((x_stationary - x1) / x_stationary) <= eps2)
{
return(x_stationary);
}
if (f.Derivative(x_stationary) * f.Derivative(x1) < 0)
{
x2 = x1;
x1 = x_stationary;
}
if (f.Derivative(x_stationary) * f.Derivative(x2) < 0)
{
x1 = x_stationary;
}
//Переход на шаг 3
x_stationary = double.NaN;
if (m < 0)
{
x_stationary = x2;
}
if (0 <= m && m <= 1)
{
x_stationary = x2 - m * (x2 - x1);
}
if (m > 1)
{
x_stationary = x2;
}
iter++;
}
return(x_stationary);
}