examples.gp
Class MathProblem.FormulaFitnessFunction

java.lang.Object
  org.jgap.gp.GPFitnessFunction
      examples.gp.MathProblem.FormulaFitnessFunction

All Implemented Interfaces:

java.io.Serializable

Enclosing class:

MathProblem

public static class MathProblem.FormulaFitnessFunction
extends GPFitnessFunction

Fitness function for evaluating the produced fomulas, represented as GP programs. The fitness is computed by calculating the result (Y) of the function/formula for integer inputs 0 to 20 (X). The sum of the differences between expected Y and actual Y is the fitness, the lower the better (as it is a defect rate here).

See Also:

Serialized Form

Field Summary

Fields inherited from class org.jgap.gp.GPFitnessFunction

MAX_FITNESS_VALUE, NO_FITNESS_VALUE

Constructor Summary

MathProblem.FormulaFitnessFunction()

Method Summary

double	computeRawFitness(IGPProgram ind)
protected double	evaluate(IGPProgram a_subject) Determine the fitness of the given GPProgram instance.

Methods inherited from class org.jgap.gp.GPFitnessFunction

getFitnessValue, getLastComputedFitnessValue, GPFitnessFunction

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

MathProblem.FormulaFitnessFunction

public MathProblem.FormulaFitnessFunction()

Method Detail

evaluate

protected double evaluate(IGPProgram a_subject)

Description copied from class: GPFitnessFunction

Determine the fitness of the given GPProgram instance. The higher the return value, the more fit the instance. This method should always return the same fitness value for two equivalent GPProgram instances.

Specified by:

evaluate in class GPFitnessFunction

Parameters:

a_subject - the GPProgram instance to evaluate

Returns:

positive double reflecting the fitness rating of the given GPProgram. Note that if a non-positive double is returned, a RuntimeException should be generated

computeRawFitness

public double computeRawFitness(IGPProgram ind)