#include #include using namespace std; double FUNC(double x) { // Change function for research here: return (50*pow(x, 4) + 200*pow(x, 3) - 580*pow(x, 2) + 99*x + 80); } // Function wich searching for minimum Ordinate by optimum Abscissa, // applying method of golden section. // In case of multiple optimums, program will find the lowest minimum. void golden_min(double &a, double &b, double &MIN, double &arg, double precision, int &count) { // Declaration and initialization of golden section const const double c = 1.61803; count++; // Integer i keep count of iterations if (FUNC(a) > FUNC(b)) { a += (b-a)*(2-c); MIN = FUNC(b); arg = b; } else { b -= (b-a)*(2-c); MIN = FUNC(a); arg = a; } // Recursion for precision calculations if (10*abs(FUNC(b) - FUNC(a)) > precision) golden_min(a, b, MIN, arg, precision, count); } int main() { // Change here bounders points of funstion [a; b], // it expected that function FUNC have at least 1 minimum between a an b. double a = -10; double b = 4; // Declaration and initialization of precision for calculations double precision = 0.001; // Declaration of variables MIN, arg (optimum x) and quantity of iterations. double MIN; double arg; int count = 0; // Giving input parameters a, b, precision and variables MIN, arg, count // to the optimum research function. golden_min(a, b, MIN, arg, precision, count); // Output of result to the screen cout << "Iteration #"<< count << ". MIN = " << MIN << "; x_opt = " << arg << endl; }

Optimum (minimum) analis with golden section method