sso_simple()

% -----------------------------------------------------------------
% Simplified Swarm Optimization (SSO) algorithm by Wei-Chang Yeh  %
% Programmed by Jing-Feng Deng at National Tsing Hua University (ROC) %
% Programming dates: May 2013                                     %
% Last revised: May 2013   (simplified version for demo only)     %
% -----------------------------------------------------------------
% Papers -- Citation Details:
% 1) C. Bae, W. C. Yeh, N. Wahid, Y.Y. Chung and Y. Liu, 
% A New Simplified Swarm Optimization (SSO) Using Exchange Local Search Scheme,
% Int. J. Innovative Computing, Information and Control,
% Vol. 8, No. 6, 4391-4406 (2012)
% http://www.ijicic.org/ijicic-11-06072.pdf

function sso_simple()
%initialize basic information
clear all
clc
close all
%nargin

Nvar = 20;
Nsol = 150;
Ngen = 100;
Nrun = 30;

Cg   = 0.55;
Cp   = 0.75;
Cw   = 0.95;

genBest= 1;
gBest  = 1;

%initialize stepint
LB   = -5.12;
UB   =  5.12;

X  = zeros(Nsol,Nvar);
pX = zeros(Nsol,Nvar);
F  = zeros(Nsol);
pF = zeros(Nsol);

for run=1:Nrun
   start_time = cputime;
   %initialize solution
   for sol=1:Nsol
      %for var=1:Nvar
      %   X(sol,var)=rand*(UB-LB)+LB;
      %   pX(sol,var) = X(sol,var);
      %end
      X(sol,:)=rand(1,Nvar).*(UB-LB)+LB;
      pX(sol,:)=X(sol,:);
      F(sol)=fitness_funtion(X, sol);
      pF(sol)=F(sol);
      if F(sol) < F(gBest)
        gBest = sol;
      end   
   end 
   
    
   for gen=1:Ngen
   %update solution 
   	  for sol=1:Nsol
         for var=1:Nvar
            random_number=rand;
            if random_number < Cg
                X(sol,var)=pX(gBest,var);
            elseif random_number< Cp
                X(sol,var)=pX(sol,var);
            elseif random_number < Cw
                continue;
            else     
                X(sol,var)=rand*(UB-LB)+LB;
            end
         end
   	  
   	    F(sol)=fitness_funtion(X, sol);
   	    if F(sol) < pF(sol)
           pF(sol) = F(sol);
           %for var=1:Nvar
           %	  pX(sol,var)=X(sol,var);
           %end
           pX(sol,:)=X(sol,:);
           if F(sol) < pF(gBest)
              gBest=sol;
              genBest=gen;
           end
        end
      end
      subplot( Nrun/5 ,5, run)
      plot(gen, pF(gBest),'r-.');
      title({['run=',num2str(run), ', gen=',num2str(gen)]...
             , ['pF(gBest)=',num2str(pF(gBest))] })
      drawnow
      hold on
   end %end of gen
   end_time = cputime;
   fprintf('RunTime=%f ',end_time - start_time);
   fprintf('BestSol=%f ',pF(gBest) );
   fprintf('genBest=%d ', genBest);
   fprintf('gBest=%d\n', gBest);
end

function top=fitness_funtion(X, sol)
    top=25;
    for var=1:size(X,2)
    	top=top+round(X(sol,var));
    end
    return