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CD.cs
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CD.cs
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using System;
using System.Collections.Generic;
using System.Text;
namespace Lab4
{
public class CD
{
public delegate double func(double[] variables);
static public double golden_section (func f, double[] vars, int var_index, double eps, double a,
double b, int max_steps_count)
{
double res = 0.0;
double phi = (1 + Math.Sqrt(5.0)) / 2.0;
double A = 0, B = 0;
double x1, x2;
int step = 0;
while ((b - a) > eps)
{
x1 = b - ((b - a) / phi);
vars[var_index] = x1;
A = f(vars);
x2 = a + ((b - a) / phi);
vars[var_index] = x2;
B = f(vars);
if (A > B)
{
a = x1;
}
else
{
b = x2;
}
step++;
if (step > max_steps_count)
{
Console.WriteLine("Over the limit");
break;
}
}
res = (a + b) / 2;
return res;
}
static public double[] descent_method (func f, double[] vars, double eps, int max_steps_count)
{
double B = f(vars), A = 0;
double delta = 0.0;
for(int i = 0; i < max_steps_count; i++)
{
A = B;
for (int var_index = 0; var_index < vars.Length; var_index++)
{
vars[var_index] = golden_section(f, vars, var_index, eps, -0.75, 0.75, max_steps_count);
}
B = f(vars);
delta = Math.Abs(A - B);
if(delta<=eps)
{
break;
}
}
return vars;
}
}
}