simulated annealing code minimize fitness function in matlab

Here is an example of how to implement the Simulated Annealing algorithm for minimizing a fitness function in MATLAB:

main.m
% Fitness function
fitness = @(x) (x-5)^2;

% Parameters
initialSolution = 0; % Initial solution
initialTemperature = 100; % Initial temperature
coolingRate = 0.95; % Cooling rate
iterations = 100; % Number of iterations

% Initialize solution
bestSolution = initialSolution;
bestFitness = fitness(bestSolution);

% Main loop
temperature = initialTemperature;
for i = 1:iterations
    % Generate a neighboring solution
    neighborSolution = bestSolution + randn();
    neighborFitness = fitness(neighborSolution);
    
    % Determine if the neighbor is accepted
    if neighborFitness < bestFitness
        bestSolution = neighborSolution;
        bestFitness = neighborFitness;
    else
        acceptanceProbability = exp((bestFitness - neighborFitness) / temperature);
        if rand() < acceptanceProbability
            bestSolution = neighborSolution;
            bestFitness = neighborFitness;
        end
    end
    
    % Update temperature
    temperature = temperature * coolingRate;
end

% Display the result
disp(['Best solution: ' num2str(bestSolution)]);
disp(['Fitness value: ' num2str(bestFitness)]);
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In this example, we define the fitness function as a anonymous function fitness. We then set the initial solution, initial temperature, cooling rate, and number of iterations.

The main loop performs the simulated annealing algorithm. In each iteration, a neighboring solution is generated by adding random noise to the current solution. If the neighbor has a lower fitness value, it is accepted as the new best solution. Otherwise, it may still be accepted based on the acceptance probability, which is determined by the temperature and the difference in fitness values between the current and neighbor solutions.

The temperature is updated after each iteration by multiplying it by the cooling rate.

Finally, the best solution and its fitness value are displayed.

Make sure to replace the fitness function @(x) (x-5)^2 with your own fitness function.

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