private double computeFitness(IGPProgram a_program, Variable vx) {
double error = 0.0f;
Object[] noargs = new Object[0];
// Initialize local stores.
// ------------------------
a_program.getGPConfiguration().clearStack();
a_program.getGPConfiguration().clearMemory();
// Compute fitness for each program.
// ---------------------------------
for (int i = 2; i < 15; i++) {
for (int j = 0; j < a_program.size(); j++) {
vx.set(new Integer(i));
try {
try {
// Only evaluate after whole GP program was run.
// ---------------------------------------------
if (j == a_program.size() - 1) {
double result = a_program.execute_int(j, noargs);
error += Math.abs(result - fib_iter(i));
} else {
a_program.execute_void(j, noargs);
}
} catch (IllegalStateException iex) {
error = Double.MAX_VALUE / 2;
break;
}
} catch (ArithmeticException ex) {
System.out.println("Arithmetic Exception with x = " + i);
System.out.println(a_program.getChromosome(j));
throw ex;
}
}
}
return error;
}
