Градиентные методы / PAR_KOS

#include <conio.h>
#include <math.h>
#include <iostream.h>

double e = 0.0000001;
double Xo[2] = {6, 6};
double p[2];

double y(double);
double dy(double);
double Swenn(int);
double Boltsano();
void AntiGrad();
double Norma(double, double);
void Method();

double y(double a)
{
 double res, x[2] = {Xo[0] + a*p[0], Xo[1] + a*p[1]};
 res = 8*x[0]*x[0] + 4*x[0]*x[1] + 5*x[1]*x[1];
 return(res);
}

double dy(double x)
{
 double res;
 res = (y(x+e) - y(x))/e;
 return(res);
}

double Swenn(int i)
{
 double a = 0.1, A, x1 = 0, x2, B;
 x2 = x1 + a;
 if (y(x1) < y(x2))
  {
   p[0] = -p[0];
   p[1] = -p[1];
  }
 while(y(x1) > y(x2))
  {
   a = 2*a;
   x1 = x2;
   x2 = x1 + a;
  }
 A = x1-a;
 B = x2;
 if (i == 1)
  return(A);
 else
  return(B);
}

double Boltsano()
{
 double x, K = 1, L, A, B;
 A = Swenn(1);
 B = Swenn(2);
 x = (A + B)/2;
 while((fabs(dy(x)) > e) || (L > e))
  {
   if (dy(x) < 0)
    A = x;
   else
    B = x;
   L = B - A;
   x = (A + B)/2;
   K++;
  }
 return(x);
}

void AntiGrad()
{
 p[0] = -16*Xo[0] - 4*Xo[1];
 p[1] = -4*Xo[0] - 10*Xo[1];
 /*while ((fabs(p[0]) > 100) && (fabs(p[1]) > 100))
  {
   p[0] = p[0] / 100;
   p[1] = p[1] / 100;
  }                    */
}

double Norma(double x, double y)
{
 double res;
 res = sqrt(x*x + y*y);
 return(res);
}

void Method()
{
 double K = 1, Min, X1[2] = {Xo[0], Xo[1]}, X2[2];

 AntiGrad();
 Min = Boltsano();
 Xo[0] += Min*p[0];
 Xo[1] += Min*p[1];      

 X2[0] = Xo[0];
 X2[1] = Xo[1];

 do
  {
   AntiGrad();
   Min = Boltsano();
   Xo[0] += Min*p[0];
   Xo[1] += Min*p[1];

   p[0] = Xo[0] - X1[0];
   p[1] = Xo[1] - X1[1];
   Min = Boltsano();
   Xo[0] += Min*p[0];
   Xo[1] += Min*p[1];

   if(Norma(p[0], p[1]) < e)
    break;

   X1[0] = X2[0];
   X1[1] = X2[1];

   X2[0] = Xo[0];
   X2[1] = Xo[1];

   K++;
  }
 while(1);
 cout << "K = " << K << endl;
}

void main()
{
 clrscr();

 Method();

 cout << "Min = (" << Xo[0] << " ," << Xo[1] << ")" << endl;

 getch();
}