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java.lang.Objectec.Problem
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.
Problem forms will define some kind of evaluation method. This method may be called in one of two ways by the Evaluator.
Problems should be prepared for both of the above situations. The easiest way to handle it is to simply evaluate each individual as his evaluate(...) method is called, and do nothing during prepareToEvaluate or finishEvaluating. That should be true for the vast majority of Problem types.
Field Summary | |
static java.lang.String |
P_PROBLEM
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Constructor Summary | |
Problem()
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Method Summary | |
java.lang.Object |
clone()
Creates a new individual cloned from a prototype, and suitable to begin use in its own evolutionary context. |
void |
closeContacts(EvolutionState state,
int result)
Called to shut down remote evaluation network contacts when the run is completed. |
Parameter |
defaultBase()
Here's a nice default base for you -- you can change it if you like |
void |
finishEvaluating(EvolutionState state,
int threadnum)
Will be called by the Evaluator after prepareToEvaluate(...) is called and then a series of individuals are evaluated. |
void |
initializeContacts(EvolutionState state)
Called to set up remote evaluation network contacts when the run is started. |
void |
prepareToEvaluate(EvolutionState state,
int threadnum)
May be called by the Evaluator prior to a series of individuals to evaluate, and then ended with a finishEvaluating(...). |
void |
reinitializeContacts(EvolutionState state)
Called to reinitialize remote evaluation network contacts when the run is restarted from checkpoint. |
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 |
equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Field Detail |
public static final java.lang.String P_PROBLEM
Constructor Detail |
public Problem()
Method Detail |
public Parameter defaultBase()
defaultBase
in interface Prototype
public void setup(EvolutionState state, Parameter base)
Prototype
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.
setup
in interface Prototype
public java.lang.Object clone()
Prototype
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.
public Object protoClone()
{
return super.clone();
}
public Object protoClone()
{
myobj = (MyObject) (super.clone());
// put your deep-cloning code here...
// ...you should use protoClone and not
// protoCloneSimple to clone subordinate objects...
return myobj;
}
public Object protoClone()
{
MyObject myobj = (MyObject)(super.protoClone());
// put your deep-cloning code here...
// ...you should use protoClone and not
// protoCloneSimple to clone subordinate objects...
return myobj;
}
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.
clone
in interface Prototype
public void prepareToEvaluate(EvolutionState state, int threadnum)
public void finishEvaluating(EvolutionState state, int threadnum)
public void initializeContacts(EvolutionState state)
public void reinitializeContacts(EvolutionState state)
public void closeContacts(EvolutionState state, int result)
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