MATLAB: Keep getting error message on the ODE function

errorMATLABode45

I am currently working on coding polymerization of PLA in a batch reactor keep getting error message. My professor helped my group get to this point but eveytime we run it we get,
Error using horzcat
Dimensions of arrays being concatenated are not consistent.
We have tried everything we can think of to fix this problem but we arent sure why this is happening or how to fix it.
Error in sad_girl_Project (line 46)
u0=[P0 zeros(N,1) 0] ;
function sad_girl_Project
T = 180+273.15; %Temperature [K]
Keq=10;
 
%% Calculations
lk1=-(6810.3/T)+6.1928
k1=exp(lk1) %rate constant for Polymerization (L/mol*s)
km1=k1/Keq %rate constant for depolymerization (L/mol*s)
P0=10;
N=100; %degree of polimerzation
% u=[P1, P2, .... PN, W]
function dudt=deq(t,u)
    
    P= u(1:N);
    W= u(N-1);
    sum3= sum(P);
 
    sum4=0;
    for ii=1:N
    
        sum1 = 0;
        for jj=1:ii-1
            sum1= sum1 + P(ii-jj)*P(jj);
        end % for jj
 
        %disp([ii, P(1:2), sum1])
 
        sum2= sum(P(ii+1:N));
        
        dudt(ii)= k1*sum1 + 2*km1*W*sum2 -             ...
                  2*k1*P(ii)*sum3 - km1*W*(ii-1)*P(ii);
                  
        sum4 = sum4 + (ii-1)*P(ii);
        
        %disp([ii, sum1, sum2 sum3])
        
    end % for ii
    
    dudt(N+1)= k1*sum3^2 - km1*W*sum4;
    dwdt(N+1)=0;
    
    dudt=[dudt; dwdt];
    
end % deq    
m=[0 24*3600] ;
u0=[P0 zeros(N,1) 0] ;
[t,u]=ode15(@deq,m,u0) ;
 
 
    %% Plot
figure(1)
plot(t,u)
title('Time Vs. Molecular Weight')
xlabel('Time []')
ylabel('Concentration []')
end

Best Answer

u0 = [P0, zeros(1, N + 1)];
Related Question