/** It applies the reproduction stage */
void Reproduction() {
int i, madre, padre;
/* First, the individual in the population are ordered according to their fitness */
Collections.sort(Poblacion);
/* Create the new population */
Poblacion2.clear();
Hijos.clear();
/* Top-half best-performing individuals will advance to the next generation */
for (i = 0; i < (tamPoblacion / 2); i++) {
Individual indi = new Individual(Poblacion.get(i));
Poblacion2.add(indi);
}
/* The remaining half is generated by performing crossover operations on individuals
in the top half */
while (Poblacion.size() != (Poblacion2.size() + Hijos.size())) {
/* 2 parents are selected */
madre = Selection();
do {
padre = Selection();
} while (madre == padre);
/* 2 children are created by crossover operator */
Crossover(madre, padre);
}
/* Create the population for the next generation */
Poblacion.clear();
for (i = 0; i < Poblacion2.size(); i++) {
Individual indi = new Individual(Poblacion2.get(i));
Poblacion.add(indi);
}
for (i = 0; i < Hijos.size(); i++) {
Individual indi = new Individual(Hijos.get(i));
Poblacion.add(indi);
}
}
/**
* It Evaluates the performance of the best evolved fuzzy system on test data. The Mean Square
* Error (MSE) is used
*
* @return double The MSE error in test data
*/
public double Evaluate_best_fuzzy_system_in_test() {
int i;
double result, suma, fuerza;
SistemaDifuso.clear();
for (i = 0; i < Nr; i++) {
Individual indi = new Individual(BestSistemaDifuso.get(i));
SistemaDifuso.add(indi);
}
suma = 0.0;
for (i = 0; i < test.getnData(); i++) {
fuerza = Output_fuzzy_system(test.getExample(i));
suma += Math.pow(test.getOutputAsReal(i) - fuerza, 2.0);
}
result = suma / test.getnData();
return (result);
}
/** It creates a fuzzy system containing Nr rules from the population */
void Create_fuzzy_system() {
int i, pos, tam;
int[] vector = new int[tamPoblacion];
for (i = 0; i < tamPoblacion; i++) {
vector[i] = i;
}
tam = tamPoblacion;
SistemaDifuso.clear();
for (i = 0; i < Nr; i++) {
pos = Randomize.RandintClosed(0, tam - 1);
Poblacion.get(vector[pos]).n_SistemasDifusos++;
Individual indi = new Individual(Poblacion.get(vector[pos]));
SistemaDifuso.add(indi);
vectorNr[i] = vector[pos];
vector[pos] = vector[tam - 1];
tam--;
}
}
/** It launches the algorithm */
public void execute() {
int i, j, num;
double fitness, fitness2;
if (somethingWrong) { // We do not execute the program
System.err.println(
"An error was found, either the data-set have numerical values or missing values.");
System.err.println("Aborting the program");
// We should not use the statement: System.exit(-1);
} else {
// We do here the algorithm's operations
Randomize.setSeed(semilla);
/* Generation of the initial population */
System.out.println("Creating the initial population.");
initializePopulation();
Gen = 0;
GenSincambio = 0;
Bestperformance = -1.0;
/* Main of the genetic algorithm */
System.out.println("Starting the evolutionary process.");
do {
/* First, all rules' fitness is set to 0 */
for (i = 0; i < tamPoblacion; i++) {
Poblacion.get(i).fitness = 0.0;
Poblacion.get(i).n_SistemasDifusos = 0;
}
/* Then Nf fuzzy system are created */
for (i = 0; i < Nf; i++) {
/* A fuzzy system containing Nr rules from the population is created */
Create_fuzzy_system();
/* The fitness asociated to this fuzzy system is calculated */
fitness = Evaluate_fuzzy_system();
/* The fitness value is accumulated among the rules in the fuzzy system */
Accumulate_fitness_fuzzy_system(fitness);
/* If the fitness of the current fuzzy system outperforms the best evolved one,
we update this last one */
if (fitness > Bestperformance) {
Bestperformance = fitness;
GenSincambio = -1;
BestSistemaDifuso.clear();
for (j = 0; j < Nr; j++) {
Individual indi = new Individual(Poblacion.get(vectorNr[j]));
BestSistemaDifuso.add(indi);
}
}
}
/* The accumulated fitness value of each individual in the population is divided
by the number of times it has been selected */
for (i = 0; i < tamPoblacion; i++) {
if (Poblacion.get(i).n_SistemasDifusos != 0) {
Poblacion.get(i).fitness /= Poblacion.get(i).n_SistemasDifusos;
} else {
Poblacion.get(i).fitness = 0.0;
}
/* Now we count the number of parameter used in the consequent, in order to
give a better fitness to those rules with a lower number of parameters */
num = 0;
for (j = 0; j < entradas; j++) {
if (Poblacion.get(i).consecuente[j] != 0.0) {
num++;
}
}
if (Poblacion.get(i).consecuente[entradas] != 0.0) {
num++;
}
Poblacion.get(i).fitness /= (K + num);
}
/* we increment the counter of the number of generations */
Gen++;
GenSincambio++;
if (GenSincambio == numGenMigration) {
/* Migration stage: half of the population (the worst one) is radomly generated again
to increase the searching ability of the genetic process */
System.out.println(
"Migrating half of the population in order to restart the evolutionary process.");
Migration();
GenSincambio = 0;
} else {
/* Reproduction stage (includes crossover) */
Reproduction();
/* Mutation */
Mutation();
}
System.out.println("Iteration: " + Gen + ". Best fitness: " + (1.0 / Bestperformance));
} while (Gen <= numGeneraciones);
String salida = new String("");
salida += Print_Population();
SistemaDifuso.clear();
for (i = 0; i < Nr; i++) {
Individual indi = new Individual(BestSistemaDifuso.get(i));
SistemaDifuso.add(indi);
}
salida += "MSE Training:\t" + (1.0 / Bestperformance) + "%\n";
salida += "MSE Test:\t\t" + Evaluate_best_fuzzy_system_in_test() + "%\n\n";
Files.writeFile(outputBC, salida);
doOutput(this.val, this.outputTr);
doOutput(this.test, this.outputTst);
System.out.println("Algorithm Finished.");
}
}
