rank scaling fitness function in matlab

To rank scaling a fitness function in MATLAB, you can follow these steps:

1. Define your fitness function: Write a MATLAB function that evaluates the fitness of individuals in your population. This function should take the individual's genotype as input and return their fitness value as output.

Here is an example of a fitness function that calculates the sum of a vector of values:

main.m
function fitness = myFitnessFunction(individual)
    fitness = sum(individual);
end
84 chars
4 lines

2. Implement ranking scaling: Once you have your fitness function defined, you can implement ranking scaling. Ranking scaling is a method to assign fitness ranks to individuals based on their fitness values. The highest-ranked individual will have the highest fitness value, and the lowest-ranked individual will have the lowest fitness value.

Here is an example of how to implement ranking scaling using MATLAB's built-in tiedrank function:

main.m
function scaledFitness = rankingScaling(fitnessValues)
    ranks = tiedrank(fitnessValues);
    scaledFitness = length(ranks) - ranks + 1;
end
143 chars
5 lines

3. Scale fitness values: Now, you can use the ranking scaling function to scale the fitness values of your population. This will ensure that the individuals with higher fitness ranks get higher scaled fitness values.

main.m
populationFitness = zeros(1, populationSize);

for i = 1:populationSize
    individual = population(i, :);
    fitness = myFitnessFunction(individual);
    populationFitness(i) = fitness;
end

scaledFitness = rankingScaling(populationFitness);
244 chars
10 lines

In this example, populationSize is the size of your population, population is a matrix representing your population, and populationFitness is a vector storing the fitness values of each individual.

Once you have the scaled fitness values, you can proceed with other steps of your evolutionary algorithm like selection, crossover, and mutation.

I hope this helps you in implementing ranking scaling for your fitness function in MATLAB!