Hi Sean,

I tried to implement MyData. But, NullPointerException was thrown when cloning the Bike_val which was used by the setup procedure of MyGPProblem(BikeTestDataGe). 
I mean:

public class MyData extends GPData {
public char char_val;
public Bike Bike_val;

@Override
public Object clone() {
MyData copy = (MyData) super.clone();

// do any additional initialization required for deep clone
copy.Bike_val = (Bike) copy.Bike_val.clone(); // NullPointerException is thrown

return copy;
}

@Override
public GPData copyTo(GPData other) {
((MyData) other).char_val = char_val;

return other;
}
}


And the stacktrace is as follows,
java.lang.NullPointerException
at testdatagen.bike.gp.MyData.clone(MyData.java:24)
at ec.gp.ADFContext.setup(ADFContext.java:135)
at ec.gp.ADFStack.setup(ADFStack.java:113)
at ec.gp.GPProblem.setup(GPProblem.java:81)
at testdatagen.bike.gp.BikeTestDataGen.setup(BikeTestDataGen.java:56)
at ec.Evaluator.setup(Evaluator.java:79)
at ec.simple.SimpleEvaluator.setup(SimpleEvaluator.java:36)
at ec.EvolutionState.setup(EvolutionState.java:313)
at ec.simple.SimpleEvolutionState.startFresh(SimpleEvolutionState.java:50)
at ec.EvolutionState.run(EvolutionState.java:360)
at ec.Evolve.main(Evolve.java:655)


It seemed that I didn't get you. Can you please little elaborate?

Thanks,
Wei



2010/11/29 Wei He <[log in to unmask]>
Thanks for your advice. I'll have a try.

Best regards,
Wei


2010/11/25 Sean Luke <[log in to unmask]>
On Nov 24, 2010, at 9:20 PM, Wei He wrote:


In the STGP example of the manual, the val variable can store both boolean and real-valued data. However, in my case, the input from the child (char data) and the the result (Bike data) of a GPNode can not use the same val variable. Should I allocate different fields for them as below?

public class MyData extends GPData {
        public char char_val;
        public Bike Bike_val;
        public GPData copyTo(GPData other) {
                  ((MyData)other).char_val = char_val;
                  ((MyData)other).Bike_val = Bike_val;
                  return other;
        }
}

Sure, that's how I'd do it.  However I would clone Bike_val rather than sharing the pointer.  Also you'll need to implement the MyData.clone() method and in it clone the Bike.  I should show that as an example in the manual.

Now it may be the case that you have certain GPNodes which can accept EITHER a char or a Bike.  In that case I would have an additional boolean which indicates which variable holds the real data.

Sean