ec
Class Problem

java.lang.Object
  |
  +--ec.Problem
All Implemented Interfaces:
java.lang.Cloneable, Prototype, java.io.Serializable, Setup
Direct Known Subclasses:
GPProblem, TeambotsProblem

public abstract class Problem
extends java.lang.Object
implements Prototype

Problem is a prototype which defines the problem against which we will evaluate individuals in a population.

Since Problems are Prototypes, you should expect a new Problem class to be cloned and used, on a per-thread basis, for the evolution of each chunk of individuals in a new population. If you for some reason need global Problem information, you will have to provide it statically, or copy pointers over during the protoClone() process (there is likely only one Problem prototype, depending on the Evaluator class used).

Note that Problem does not implement a specific evaluation method. Your particular Problem subclass will need to implement a some kind of Problem Form (for example, SimpleProblemForm) appropriate to the kind of evaluation being performed on the Problem. These Problem Forms will provide the evaluation methods necessary.

See Also:
Serialized Form

Field Summary
static java.lang.String P_PROBLEM
           
 
Constructor Summary
Problem()
           
 
Method Summary
 Parameter defaultBase()
          Here's a nice default base for you -- you can change it if you like
 java.lang.Object protoClone()
          Creates a new individual cloned from a prototype, and suitable to begin use in its own evolutionary context.
 java.lang.Object protoCloneSimple()
          This should be implemented in a the top-level Prototype ONLY; in fact, it should probably be declared final.
 void setup(EvolutionState state, Parameter base)
          Sets up the object by reading it from the parameters stored in state, built off of the parameter base base.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

P_PROBLEM

public static final java.lang.String P_PROBLEM
Constructor Detail

Problem

public Problem()
Method Detail

defaultBase

public Parameter defaultBase()
Here's a nice default base for you -- you can change it if you like
Specified by:
defaultBase in interface Prototype

setup

public void setup(EvolutionState state,
                  Parameter base)
Description copied from interface: Prototype
Sets up the object by reading it from the parameters stored in state, built off of the parameter base base. If an ancestor implements this method, be sure to call super.setup(state,base); before you do anything else.

For prototypes, setup(...) is typically called once for the prototype instance; cloned instances do not receive the setup(...) call. setup(...) may be called more than once; the only guarantee is that it will get called at least once on an instance or some "parent" object from which it was ultimately cloned.

Specified by:
setup in interface Prototype

protoClone

public java.lang.Object protoClone()
                            throws java.lang.CloneNotSupportedException
Description copied from interface: Prototype
Creates a new individual cloned from a prototype, and suitable to begin use in its own evolutionary context.

The question here is whether or not this means to perform a "deep" or "light" ("shallow") clone, or something in-between. You may need to deep-clone parts of your object rather than simply copying their references, depending on the situation:

Implementations.

If you know that your superclasses will never change their protoClone() implementations, you might try inlining them in your overridden protoClone() method. But this is dangerous (though it yields a small net increase).

In general, you want to keep your deep cloning to an absolute minimum, so that you don't have to call protoClone() but one time.

The approach taken here is the fastest that I am aware of while still permitting objects to be specified at runtime from a parameter file. It would be faster to use the "new" operator; but that would require hard-coding that we can't do. Although using java.lang.Object.clone() entails an extra layer that deals with stripping away the "protected" keyword and also wrapping the exception handling (which is a BIG hit, about three times as slow as using "new"), it's still MUCH faster than using java.lang.Class.newInstance(), and also much faster than rolling our own Clone() method.

Specified by:
protoClone in interface Prototype

protoCloneSimple

public java.lang.Object protoCloneSimple()
Description copied from interface: Prototype
This should be implemented in a the top-level Prototype ONLY; in fact, it should probably be declared final. It should be implemented as follows:

public final Object protoCloneSimple()
{
try { return protoClone(); }
catch (CloneNotSupportedException e) 
{ throw new InternalError(); } // never happens
} 
Specified by:
protoCloneSimple in interface Prototype