I am unable to store values for every iteration, values are overwritten in each iteration.

 for p = 4:4:population
        routes = pop(rand_pair(p-3:p),:);
        dists = total_dist(rand_pair(p-3:p));
        [~,idx] = min(dists);
        best_of_4_route = routes(idx,:);
        ins_pts = sort(ceil(n*rand(1,2)));
        I = ins_pts(1);
        J = ins_pts(2);
        for k = 1:4
            tmp_pop(k,:) = best_of_4_route;
            switch k
                case 2 
                    tmp_pop(k,I:J) = fliplr(tmp_pop(k,I:J));
                case 3
                    tmp_pop(k,[I J]) = tmp_pop(k,[J I]);
                case 4
                    tmp_pop(k,I:J) = tmp_pop(k,[I+1:J I]);
                otherwise
            end
            display(best_of_4_route);
            display(d);

           % diary on
           a_str = sprintf('%e\t',d);
            fid = fopen('newfile.txt','w');
            fprintf(fid, '%s', a_str);
            fclose(fid);

        new_pop(p-3:p,:) = tmp_pop;
        end

I want to store value of 'best_of_4_route', 'd' for every iteration. The code I have written only overwrite.

Answer 1

[Mahdi]

This is only one of many ways (I would suggest pre-locating but I need more of the code) *Before *the for loop, add this line:

best_of_4_route=[];

And change your the line inside the for loop to

best_of_4_route =[best_of_4_route; routes(idx,:)];

Similar logic for d.

[Mahdi]

This stores all of the data in a matrix where the row corresponds to the loop.

[Sanuj Shukla]

for p = 4:4:population routes= pop(rand_pair(p-3:p),:);

        dists = total_dist(rand_pair(p-3:p));

        [~,idx] = min(dists);
        best_of_4_route = routes(idx,:);
        ins_pts = sort(ceil(n*rand(1,2)));
        I = ins_pts(1);
        J = ins_pts(2);

    best=[]; 

        for k = 1:4
           tmp_pop(k,:) = best_of_4_route;
            switch k
                case 2 
                    tmp_pop(k,I:J) = fliplr(tmp_pop(k,I:J));
                case 3
                    tmp_pop(k,[I J]) = tmp_pop(k,[J I]);
                case 4
                    tmp_pop(k,I:J) = tmp_pop(k,[I+1:J I]);
                otherwise

        end
            display(best_of_4_route);
            display(d);
best=[best_of_4_route; routes(idx,:)];

        end

Its not working. I don't know the correct way to do that.

[Mahdi]

I meant the first for loop. Try this:

best_of_4_route=[]
for p = 4:4:population
      routes = pop(rand_pair(p-3:p),:);
      dists = total_dist(rand_pair(p-3:p));
      [~,idx] = min(dists);
      best_of_4_route = [best_of_4_route; routes(idx,:)];
      ins_pts = sort(ceil(n*rand(1,2)));
      I = ins_pts(1);
      J = ins_pts(2);
      for k = 1:4
          tmp_pop(k,:) = best_of_4_route;
          switch k
              case 2 
                  tmp_pop(k,I:J) = fliplr(tmp_pop(k,I:J));
              case 3
                  tmp_pop(k,[I J]) = tmp_pop(k,[J I]);
              case 4
                  tmp_pop(k,I:J) = tmp_pop(k,[I+1:J I]);
              otherwise
          end
          display(best_of_4_route);
          display(d);

           % diary on
           a_str = sprintf('%e\t',d);
            fid = fopen('newfile.txt','w');
            fprintf(fid, '%s', a_str);
            fclose(fid);

        new_pop(p-3:p,:) = tmp_pop;
        end
end

[Sanuj Shukla]

Its not working.. only top 6 nodes are stored of each route, and overwritten again in 'newfile.txt'.

            best = [best; routes(idx,:)];
            save('d')
            a_str = sprintf('%d\t',best);
            fid = fopen('newfile.txt','w');
            fprintf(fid, '%s', a_str);
            fclose(fid);

 However 50x77 size matrix stores 77 routes when i save workspace by using  save('d'). But i need to use it in txt file.