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java.lang.Objectec.simple.SimpleFitness
A simple default fitness, consisting of a single floating-point value which ranges from 0 (worst), and where fitness A is superior to fitness B if and only if A > B. Fitness values may range from [0.0,infinity), so in theory "infinity" could be the ideal fitness -- but in fact you can have any maximum ideal fitness because when you set a fitness, you specify whether or not it is the ideal.
Default Base
simple.fitness
Field Summary | |
protected float |
fitness
|
static java.lang.String |
FITNESS_PREAMBLE
|
protected boolean |
isIdeal
|
static java.lang.String |
P_FITNESS
|
Constructor Summary | |
SimpleFitness()
|
Method Summary | |
boolean |
betterThan(Fitness _fitness)
Should return true if this fitness is clearly better than _fitness; You may assume that _fitness is of the same class as yourself. |
Parameter |
defaultBase()
Returns the default base for this prototype. |
boolean |
equivalentTo(Fitness _fitness)
Should return true if this fitness is in the same equivalence class as _fitness, that is, neither is clearly bettter or worse than the other. |
float |
fitness()
Should return an absolute fitness value ranging from negative infinity to infinity, NOT inclusive (thus infinity, negative infinity, and NaN are NOT valid fitness values). |
boolean |
isIdealFitness()
Should return true if this is a good enough fitness to end the run |
void |
printFitness(EvolutionState state,
int log,
int verbosity)
Presently does not encode the fact that the fitness is ideal or not |
void |
printFitness(EvolutionState state,
java.io.PrintWriter writer)
Presently does not encode the fact that the fitness is ideal or not |
void |
printFitnessForHumans(EvolutionState state,
int log,
int verbosity)
Presently does not print the fact that the fitness is ideal or not |
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 |
readFitness(EvolutionState state,
java.io.LineNumberReader reader)
Presently does not decode the fact that the fitness is ideal or not |
void |
setFitness(EvolutionState state,
float _f)
Deprecated. |
void |
setFitness(EvolutionState state,
float _f,
boolean _isIdeal)
|
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 |
public static final java.lang.String FITNESS_PREAMBLE
public static final java.lang.String P_FITNESS
protected float fitness
protected boolean isIdeal
Constructor Detail |
public SimpleFitness()
Method Detail |
public Parameter defaultBase()
Prototype
defaultBase
in interface Prototype
public java.lang.Object protoClone() throws java.lang.CloneNotSupportedException
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() throws CloneNotSupportedException
{
return super.clone();
}
public Object protoClone() throws CloneNotSupportedException
{
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() throws CloneNotSupportedException
{
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.
protoClone
in interface Prototype
java.lang.CloneNotSupportedException
public java.lang.Object protoCloneSimple()
Prototype
public final Object protoCloneSimple()
{
try { return protoClone(); }
catch (CloneNotSupportedException e)
{ throw new InternalError(); } // never happens
}
protoCloneSimple
in interface Prototype
public void setFitness(EvolutionState state, float _f)
public void setFitness(EvolutionState state, float _f, boolean _isIdeal)
public float fitness()
Fitness
You are free to restrict this range any way you like: for example, your fitness values might fall in the range [-5.32, 2.3]
Selection methods relying on fitness proportionate information will assume the fitness is non-negative and should throw an error if it is not. Thus if you plan on using FitProportionateSelection, BestSelection, or GreedyOverselection, for example, your fitnesses should assume that 0 is the worst fitness and positive fitness are better. If you're using other selection methods (Tournament selection, various ES selection procedures, etc.) your fitness values can be anything.
Similarly, if you're writing a selection method and it needs positive fitnesses, you should check for negative values and issue an error; and if your selection method doesn't need an absolute fitness value, it should use the equivalentTo() and betterThan() methods instead.
If your fitness scheme does not use a metric quantifiable to a single positive value (for example, MultiObjectiveFitness), you should perform some reasonable translation.
fitness
in interface Fitness
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 boolean isIdealFitness()
Fitness
isIdealFitness
in interface Fitness
public boolean equivalentTo(Fitness _fitness)
Fitness
equivalentTo
in interface Fitness
public boolean betterThan(Fitness _fitness)
Fitness
betterThan
in interface Fitness
public void printFitness(EvolutionState state, int log, int verbosity)
printFitness
in interface Fitness
public void printFitness(EvolutionState state, java.io.PrintWriter writer)
printFitness
in interface Fitness
public void printFitnessForHumans(EvolutionState state, int log, int verbosity)
printFitnessForHumans
in interface Fitness
public void readFitness(EvolutionState state, java.io.LineNumberReader reader) throws java.io.IOException, java.lang.CloneNotSupportedException
readFitness
in interface Fitness
java.io.IOException
java.lang.CloneNotSupportedException
|
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