source: liacs/nc/low-correlation/sa.m@ 43

% Simulated Annealing low-autocorrelation program
% BSDLicence
% Rick van der Zwet - 0433373 - <hvdzwet@liacs.nl>

function [iteration_history,fitness_history] = sa(seq, stopLimit)
    fitness = 0;
    temperature = stopLimit;

    iteration_history = [];
    fitness_history = [];

    for iteration = 1:stopLimit
        % Generate new mutation
        newseq = mutation(seq);

        new_fitness = autocorrelation(newseq);

        % Better is always accept
        if (new_fitness > fitness)
            fitness = new_fitness;
            % disp(rot90(newseq,-1));
            temperature = temperature - 10;
        else
            % Make the next 'move' less atractive
            temperature = temperature + 1;

            % Accept on an certain probability
            if (temperature < 1)
                break;
            else 
                % XXX: Some more cleaver cooling would be great
                if( exp(1)^((fitness - new_fitness) / temperature) > rand())
                    seq = newseq;
               end
           end
        end
        iteration_history = [ iteration_history, iteration ];
        fitness_history = [ fitness_history, fitness ]; 
    end
end