Error using Reshape pls help

My code is as follows and the error i get is

Error using reshape To RESHAPE the number of elements must not change.

Error in maint (line 148) l_dp=reshape(l_dp1,4,8);

Can someone pls help

code:-

     % delta_edp : if link e on path p used for demand d
      % x_dp  : if path used for demand
      % y_e  : if link e used in any primary path
      % l_dp : the fraction of traffic via path p
      %link

      global  hd ce Ye delta_edp X_dp ;

      link(1,:)=[1 2];
      link(2,:)=[1 3];
      link(3,:)=[1 4];
      link(4,:)=[2 6];
     link(5,:)=[3 6];
     link(6,:)=[3 7];
     link(7,:)=[4 8];
     link(8,:)=[4 9];
     link(9,:)=[6 10];
     link(10,:)=[7 10];
     link(11,:)=[8 11];
     link(12,:)=[8 12];
     link(13,:)=[9 12];
     link(14,:)=[9 13];
     link(15,:)=[1 5];
     link(16,:)=[5 13];

     %primary path    
      Pd_pr(1,:)=[2, 6, 10];
      Pd_pr(2,:)=[3,7,11];
      Pd_pr(3,:)=[3,7,12];
      Pd_pr(4,:)=[15, 16,0];

      %sencondary path
      Pd_s(1,:)=[1,4,9];
      Pd_s(2,:)=[2,5,9];
      Pd_s(3,:)=[3,8,13];
      Pd_s(4,:)=[3,8,14];

      path=[Pd_pr;Pd_s];

      %link capacity
      ce=[50 50 200 50 50 50 150 50 50 50 50 50 50 50 50 50];

      %demand
      demand=[1 10;1 11;1 12;1 13];

      %associated flow values for demand
      hd=[50 50 50 50];

      %value of X_dp
      X_dp=zeros(4,8);

      for jj=1:4
          for kk=1:8
              demandStart=demand(jj,1); %start node of demand
              demandEnd=demand(jj,2); %end node of demand
              pathStart=path(kk,1);    %start node of path
              linkStart=link(pathStart,1);%start node of link
              pathEnd=path(kk,3);  %end node of path
              if pathEnd==0
                  pathEnd=path(kk,2);
              end

              linkEnd=link(pathEnd,2); %end node of link
              if pathEnd==0
                  pathEnd=path(kk,2);
              end
              if demandStart==linkStart && demandEnd==linkEnd
                  X_dp(jj,kk)=1;
              end
          end
      end

       X_dp1=reshape(X_dp,1,[]); 

      %value of delta_edp
      delta_edp=zeros(16,4,8);

      for ii=1 : 16 % link
          for jj=1: 4 % demand
              for kk=1:8 % path
                  for nn=1:3 %link of path
                      if path(kk,nn)==ii && X_dp(jj,kk)==1
                          delta_edp(ii,jj,kk)=1;
                      end
                  end
              end
          end
      end

      %value of Ye
      Ye=zeros(16,1);
      for ii=1:16 %link
          for kk=1:4 %demand
              for nn=1:3 %link of path
                  if Pd_pr(kk,nn)==ii
                      Ye(ii)=1;
                  end
              end
          end
      end

lb = zeros(1,32); ub=X_dp1;

%fh = double (f) ;

%options = optimoptions('intlinprog','Display','iter'); %intcon=1:32; %[x,fval,exitflag,output]=intlinprog(f,... % 32,intcon,[],[],[],lb,ub,options);

options = gaoptimset('Generations',50,'PopulationSize',42,... 'PlotFcns',@gaplotbestf); nonlcon=@constraint; [x,fval,exitflag] = ga(@objectiveFun,... 32,[],[],[],[],lb,ub,nonlcon,options);

l_dp=reshape(x,4,8)

min_romax=fval;

Answer 1

[Chad Greene]

How many elements are in l_dp before you try to reshape it? To reshape it into a 4 x 8 arrangement, numel(l_dp) must equal 32. Here's an example

a = magic(6)

Above, a is 6-by-6 and thus has as 36 elements. You can reshape a into a 4-by-9 matrix by

a = reshape(a,4,9)

because 4 times 9 is 36, meaning there's you're not trying to change the number of elements in a when you reshape it. If you try to reshape a into a 4-by-8 matrix, it'll give you an error:

reshape(a,4,8)
Error using reshape
To RESHAPE the number of elements must not change.

[Bhavz]

Thanks for that !