@Override
public Double mutate(Uniform uniform, Object previousValue) {
double y = (Double) previousValue;
double yl = min;
double yu = max;
double delta1 = (y - yl) / (yu - yl);
double delta2 = (yu - y) / (yu - yl);
double rnd = uniform.nextDoubleFromTo(0.0, 1.0);
double mut_pow = 1 / (eta_m + 1);
double deltaq;
if (rnd <= 0.5) {
double xy = 1 - delta1;
double val = 2 * rnd + (1 - 2 * rnd) * (Math.pow(xy, (eta_m + 1)));
deltaq = Math.pow(val, mut_pow) - 1;
} else {
double xy = 1 - delta2;
double val = 2 * (1 - rnd) + 2 * (rnd - 0.5) * (Math.pow(xy, (eta_m + 1)));
deltaq = 1 - (Math.pow(val, mut_pow));
}
y = y + deltaq * (yu - yl);
if (y < yl) y = yl;
if (y > yu) y = yu;
return y;
}
@Override
public double nextDoubleUniform(double min, double max) {
return uniform.nextDoubleFromTo(min, max);
}
@Override
public Double[] crossoverSBX(Uniform U, Object genesA, Object genesB) {
Double gA = (Double) genesA;
Double gB = (Double) genesB;
if (U.nextDoubleFromTo(0, 1) < 0.5) {
double rand;
double y1, y2, yl, yu;
double c1, c2;
double alpha, beta, betaq;
if (StrictMath.abs(gA - gB) > EPS) {
if (gA < gB) {
y1 = gA;
y2 = gB;
} else {
y1 = gB;
y2 = gA;
}
yl = min;
yu = max;
rand = U.nextDoubleFromTo(0, 1);
beta = 1.0 + (2.0 * (y1 - yl) / (y2 - y1));
alpha = 2.0 - StrictMath.pow(beta, -(eta_c + 1.0));
if (rand <= (1.0 / alpha)) {
betaq = StrictMath.pow((rand * alpha), (1.0 / (eta_c + 1.0)));
} else {
betaq = StrictMath.pow((1.0 / (2.0 - rand * alpha)), (1.0 / (eta_c + 1.0)));
}
c1 = 0.5 * ((y1 + y2) - betaq * (y2 - y1));
beta = 1.0 + (2.0 * (yu - y2) / (y2 - y1));
alpha = 2.0 - StrictMath.pow(beta, -(eta_c + 1.0));
if (rand <= (1.0 / alpha)) {
betaq = StrictMath.pow((rand * alpha), (1.0 / (eta_c + 1.0)));
} else {
betaq = StrictMath.pow((1.0 / (2.0 - rand * alpha)), (1.0 / (eta_c + 1.0)));
}
c2 = 0.5 * ((y1 + y2) + betaq * (y2 - y1));
if (c1 < yl) c1 = yl;
if (c2 < yl) c2 = yl;
if (c1 > yu) c1 = yu;
if (c2 > yu) c2 = yu;
if (U.nextDoubleFromTo(0, 1) <= 0.5) {
return new Double[] {c2, c1};
} else {
return new Double[] {c1, c2};
}
} else {
if (U.nextDoubleFromTo(0, 1) <= 0.5) {
return new Double[] {gA, gB};
} else {
return new Double[] {gB, gA};
}
}
} else {
return new Double[] {gA, gB};
}
}
@Override
public Double generateRandomnly(Uniform uniform) {
return uniform.nextDoubleFromTo(min, max);
}