MATLAB: Error using Reshape pls help

reshape function

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;

Best Answer

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.