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.