Hi Sean,

By your revision and some additional debugging on other cooperative classes,
the code works as my intention now. I am very grateful for your help.

BTW,  what is your plan about the ECJ manual?
I found some tiny spelling and typewriting errors in GP related chapters. Do
you need a errata sheet for later update?

Wei

2010/11/30 Sean Luke <[log in to unmask]>

> Wei, there are several basic Java errors in your class below.  Here is a
> revised version which fixes them but I've not tested it.
>
> Sean
>
>
>
> public class MyData extends GPData {
>
>        public char char_val;
>        public Bike Bike_val = new Bike_val();
>
>
>        public Object clone() {
>                MyData copy = (MyData) super.clone();
>                copy.Bike_val = (Bike) (Bike_val.clone());
>                return copy;
>
>        }
>
>        public GPData copyTo(GPData other) {
>                ((MyData) other).char_val = char_val;
>                other.Bike_val = (Bike) (Bike_val.clone());
>                return other;
>
>        }
> }
>
>
> On Nov 30, 2010, at 4:16 AM, Wei He wrote:
>
>  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
>>
>>
>>