functions.cpp

//
// Created by Paulius on 2019-05-21.
// Functions taken from http://www-optima.amp.i.kyoto-u.ac.jp/member/student/hedar/Hedar_files/TestGO_files/Page364.htm
//

#include <cmath>
#include "functions.h"


/* Number of variables: n = 2.
 * Search domain: −10 ≤ xi ≤ 10, i = 1, 2.
 * Number of local minima: several local minima.
 * The global minimum: x* =  (1, 3), f(x*) = 0 */
double funcBooth(std::vector<double> &X) {
    return pow(X[0] + 2 * X[1] - 7, 2) + pow(2 * X[0] + X[1] - 5, 2);
}

/* Number of variables: n variables.
 * Search domain: −5.12 ≤ xi ≤ 5.12, i = 1, 2, . . . , n.
 * Number of local minima: several local minima.
 * The global minima: x* =  (0, …, 0), f(x*) = 0. */
double funcRastrigin(std::vector<double> &X) {
    double s = 0;
    for (auto &j: X) {
        s = s + (pow(j, 2) - 10 * cos(2 * M_PI * j));
    }
    return 10 * X.size() + s;
}

double funcMatyas(std::vector<double> &X) {
    return 0.26 * (pow(X[0], 2) + pow(X[1], 2)) - 0.48 * X[0] * X[1];
}

double funcGoldsteinAndPrice(std::vector<double> &X) {
    double a, b;
    a = 1 +
        pow(X[0] + X[1] + 1, 2) * (19 - 14 * X[0] + 3 * pow(X[0], 2) - 14 * X[1] + 6 * X[0] * X[1] + 3 * pow(X[1], 2));
    b = 30 + pow(2 * X[0] - 3 * X[1], 2) *
             (18 - 32 * X[0] + 12 * pow(X[0], 2) + 48 * X[1] - 36 * X[0] * X[1] + 27 * pow(X[1], 2));
    return a * b;

}

double funcEasom(std::vector<double> &X) {
    return -1 * std::cos(X[1]) * std::cos(X[1]) * pow(M_E, -1 * pow(X[0] - M_PI, 2) - pow(X[1] - M_PI, 2));
}

double funcBeale(std::vector<double> &X) {
    return pow(1.5 - X[0] * (1 - X[1]), 2) + pow(2.25 - X[0] * (1 - pow(X[1], 2)), 2) +
           pow(2.625 - X[0] * (1 - pow(X[1], 3)), 2);
}

double funcBranin(std::vector<double> &X) {
    return pow(X[1] - (5.1 / (4 * pow(M_PI, 2))) * pow(X[0], 2) + 5 * X[0] / M_PI - 6, 2) +
           10 * (1 - 1 / (8 * M_PI)) * std::cos(X[0]) + 10;
}

double funcHump(std::vector<double> &X) {
    return 1.0316285 + 4 * pow(X[0], 2) - 2.1 * pow(X[0], 4) + pow(X[0], 6) / 3 + X[0] * X[1] - 4 * pow(X[1], 2) +
           4 * pow(X[1], 4);
}

double funcZakharov(std::vector<double> &X) {
    double s1 = 0, s2 = 0;
    unsigned int i = 0;
    for (auto &j: X) {
        s1 = s1 + pow(j, 2);
        s2 = s2 + 0.5 * i * j;
        i++;
    }
    return s1 + pow(s2, 2) + pow(s2, 4);
}

double funcSumSquares(std::vector<double> &X) {
    double s = 0;
    for (auto i = 0; i != X.size(); i++) {
        s = s + (i + 1) * pow(X[i], 2);
    }
    return s;
}

double funcSphere(std::vector<double> &X) {
    double s = 0;
    for (int i = 0; i != X.size(); i++) {
        s = s + pow(X[i], 2);
    }
    return s;
}