Documentation of objtsp1

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Function Synopsis

ObjVal = objtsp1(routes, option)

Help text

 OBJective function for the traveling salesman example

 This function computes the length of the routes given by the
 individuals. The variables of the individuals define the order
 of the points to travel. The distance between all points is 
 given by the parameter option (DistMat).
 These problems are known as Travelling salesman (TSP).

 Syntax: ObjVal = objtsp1(routes, option)

 Input parameter:
    routes    - Matrix containg the variables of the individuals 
                   (the points of the routes).
    option    - if routes contains a matrix with the individuals, 
                   than option contains the distance matrix between 
                   the citys (points of travel),
                elseif routes == [] and
                option == 1 (or []) return boundaries (here just 
                             the number of variables and the 
                             corresponding upper/lower bounds)
                option == 2 return title for figures or docu
                option == 3 return value of global minimum

 Output parameter:
    ObjVal    - Matrix containing the objective values for the individuals
                  in routes (length of the routes).

 See also: scrtsp1, tbxperm, initpp, mutswap, mutexch, recgp, recpm

Listing of function objtsp1

% Author:   Hartmut Pohlheim
% History:  22.07.1998  file created
%           08.09.1998  many comments added


function ObjVal = objtsp1(routes, option)

   if isempty(routes),
      % Default dimension of objective function
      Dim = 20;
      % return text of title for graphic output
      if option == 2
         ObjVal = ['Travelling Salesman 1'];
      % return value of global minimum
      elseif option == 3
         ObjVal = 13029;
      % define size of boundary-matrix and values
      else   
      % these values are not necessary, the toolbox just needs the number of variables
         VLB = ones(1, Dim);
         VUB = Dim * ones(1, Dim);
	      ObjVal = [VLB; VUB];
      end
   else
      % Get number of routes and their length
      [Nroutes, Lroute] = size(routes);
      DistMat = option;
   
      % Calculate the distance of each route
      dist = zeros(Nroutes, 1);
      dist1= zeros(Nroutes, 1);
      for i = 1:Nroutes,
         % diag(DistMat(routes(i,1:Lroute), routes(i,[2:Lroute,1])))
         dist(i) = sum(diag(DistMat(routes(i,1:Lroute), routes(i,[2:Lroute,1]))));

         % old unvectorized version, takes 4-5 times as long as vectorized
         % for j = 2:Lroute, dist(i) = dist(i) + DistMat(routes(i, j - 1), routes(i, j)); end
         % dist(i) = dist(i) + DistMat(routes(i, Lroute), routes(i, 1));
      end
      ObjVal = dist;
      
   end
   

% End of function