keep getting mtimes error and don't understand why

Hello everybody

my problem is this. I'm building a code for a simulator but i keep getting mtimes error even thought my matrices and vectors have completely the same values. Here's the code

n = 1000; % Number of vector elements

L = 1; % Depth [mum]

h = L/n; % Spacial step size

dt =1; % Time step size [s]

T_fin = 1000; % End time value
m = 1/dt;
T = 1023; % Temprature [K]
% err = 1e-4; % Accepted error (recommended 1e-6)

t = 1:dt:T_fin; % Time vector
x = linspace(0,L,n); % Spacial vector

% Definition constants (From problem definition)
C_I_0=10 ; % Initial concentration of C_I [mum^-3]
C_s_0 =10; % Initial concentration of C_s [mum^-3]
C_i_0 = 10^(-2); % Initial concentration of C_i [mum^-3]
C_c_0 = 10^(-5); % Initial concentration of C_c [mum^-3]
D_B = 7.87*10^(8)*exp(-3.75/((8.6e-5)*T)); % Diffusion of B [mum^2/s]
D_I = 149*10^(8)*exp(-4.68/(8.6e-5*T)); % Diffusion of Silicon self I [mum^2/s]
C_I_eq=10^(-3); %[mum^-3]
C_Istar=C_I_0*exp(-0.56/(8.6e-5*T));%[cm^-3[
C_sp=10^(-4); %[cm^-3[
C_ip=10^3;%[mum^-3[
C_cp=10^7;%[mum^-3[
K_f = -1e-29*t+9e-28;% Kf value [mum^3/s]
 K_b=K_f*C_Istar; % [1/s]
K_1b=K_b;
K_1f=K_f;

%%Initial conditions
C_I =C_i_0* ones(T_fin,n); % Initial guess
C_s =C_sp* ones(T_fin,n); % Initial guess
C_i = C_ip* ones(T_fin,n); % Initial guess
C_c =C_cp* ones(T_fin,n); % Initial guess

C_i(1,:) = C_ip*exp(-(x-0.5).^2/(2*0.106)^2);
C_I(1,:) =C_I_0 ;
C_s(1,:) = C_sp*exp(-(x-0.5).^2/(2*0.106)^2);
C_c(1,:) = C_cp*exp(-(x-0.09).^2/(2*0.127)^2);

D_i=D_B*(C_I/C_I_eq);

figure ; plot(x,C_s(1,:));

%%Where the FUN is

for j = 1:T_fin-1
    C_s(j+1,:) = C_s(j,:) + dt*(K_1f(j)*C_i(j,:)-K_1b(j)*C_s(j,:)*C_I(j,:));
    if(j<=100) 
        for i = 2: n-1
          C_i(j+1,i) = C_i(j,i) + (dt/h^2)*D_B*(C_i(j,i+1)-2*C_i(j,i)+C_i(j,i-1)) - C_s(j,i) - dt*(K_f(j)*C_i(j,i)-K_b*C_s(j,i)*C_I(j,i)); % Assuming D_i is constant in time
          C_c(j+1,i) = C_c(j,i) + (dt/h^2)*D_I*(C_I(j,i+1)-2*C_I(j,i)+C_I(j,i-1));
        end
    end

      if(j>100)
              K_b=40; %[mum^-3]
           C_c(j+1,:) = C_c(j,:) + dt*(-K_b*C_c(j,:));
        for i=1:n-1
            C_i(j+1,i) = C_i(j,i) + (dt/h^2)*D_i(j)*(C_i(j,i+1)-2*C_i(j,i)+C_i(j,i-1)) - C_s(j,i) - dt*(K_f(j)*C_i(j,i)-K_b*C_s(j,i)*C_I(j,i)); 
                  C_I(j+1,i) = C_I(j,i) + (dt/h^2)*D_I*(C_I(j,i+1)-2*C_I(j,i)+C_I(j,i-1)) + C_s(j,i) + dt*(K_f(j)*C_i(j,i)-K_b*C_s(j,i)*C_I(j,i)) - C_c(j,i) - dt*(K_f(j)*C_I(j,i)*C_c(j,i)-K_b*C_c(j,i));
        end
          end
  end

%%Plotting
figure;
semilogy(x,C_s(2,:));
title('At time T=1'); xlabel('Depth  [\mum]'); ylabel('Concentration of Boron [cm^-3]');

%figure;
%semilogy(x,C_i(1,:)+C_s(1,:));
%title('At time t=0'); xlabel('Depth  [\mum]'); ylabel('Concentration of Boron [cm^-3]');

Be very glad if anyone could help

[Jan]

Please format the code an mention the line, which causes the error. See the "{} Code" button.

Answer 1

[Star Strider]

Your arrays are quite definitely not all the same size. For example, ‘C_s’ is (1000x1000), ‘K_1f’ is (1x1000) and the others are similarly variegated. You can probably add and multiply the results of those operations if they end up all being the same dimensions, but you cannot as you have written your equations.

I don’t know what you’re doing, so I can’t suggest a solution, for example whether you need to do matrix or array operations. You will have to sort those problems yourself.