Error using vertcat Dimensions of arrays being concatenated are not consistent.

Scrip file:

timestart=0;
timeEnd=600;
timespan=[timestart timeEnd]; % Range for the independent variable time

y0= [0.67 0.1 0.01 0.71 1 1 1 0.68 0.12 0.02 0.72 ]; % assumed initial values for the compositions which are dependant variables

v=0.6; % superficial gas phase velocity in m/s
e= 0.5; % fixed bed void fraction
d=6000 ;% density of solid OSM in kg/m^3
P= 1 ;% pressure in atm
T=1073; % temperature in kelvin
R= 0.08206; % gas constant in L.atm/K.mol
M=67 ;% molar mass of solid OSM in g/mol
z2= 2 ;% lenght of the reactor in meters
z1=1;
z0=0;

[t y]=ode45(@(t,y)rxn(t,y),timespan,y0);

plot(t,y);
legend('Xa','Xb');
ylabel('species a');
xlabel('time (s)');
axis([0 600 0 1]);
title('species a with time')

function f = rxn(t,Y)

Xa=Y(1:2);
Xb=Y(3:4);
Xc=Y(5:6);
Xd=Y(7:8);
Xe=Y(9);
Xf=Y(10);
Xg=Y(11);

% parameters

v=0.6; % superficial gas phase velocity in m/s
e= 0.5; % fixed bed void fraction
d=6000 ;% density of solid OSM in kg/m^3
P= 1 ;% pressure in atm
T=1073; % temperature in kelvin
R= 0.08206; % gas constant in L.atm/K.mol
M=67 ;% molar mass of solid OSM in g/mol
z2= 2 ;% lenght of the reactor in meters
z1=z2/2;
z0=0;

% explicit equations

Ct= P/(R*T); % total gas concentration
gc=(d*(1-e))/(Ct*e);

% rate laws (assumptions used)

ra= 20;
rb=20;
rc=20;
rd=20;
re=20;
rf=200;
rg=20;

% differential equations 

dXadt= (-v/e)*((Xa(1))/(z1-z0))+gc*ra % equation for gas components A
dXadt(2)= (-v/e)*((Xa(2))/(z2-z1))+gc*ra


dXbdt= (-v/e)*((Xb(1))/(z1-z0))+gc*rb % equation for gas components B
dXbdt(2)= (-v/e)*((Xb(2))/(z2-z1))+gc*rb

dXcdt= (-v/e)*((Xc(1))/(z1-z0))+gc*rc % equation for gas components C 
dXcdt(2)= (-v/e)*((Xc(2))/(z2-z1))+gc*rc

dXddt= (-v/e)*((Xd(1))/(z1-z0))+gc*rd % equation for gas components D
dXddt(2)= (-v/e)*((Xd(2))/(z2-z1))+gc*rd

dXedt= M*re % equation for solid components E
dXfdt= M*rf % equation for solid components F
dXgdt= M*rg % equation for solid components G

f=[dXadt; dXbdt; dXcdt; dXddt; dXedt, dXfdt; dXgdt]

end

I'm getting the following errors and I don't understand why: I've tried everything, I think I'm not understanding a basic MATLAB concept

Error using vertcat
Dimensions of arrays being concatenated are not consistent.
Error in rxn (line 62)
f=[dXadt; dXbdt; dXcdt; dXddt; dXedt, dXfdt; dXgdt]

Error in rwgs>@(t,y)rxn(t,y) (line 20)
[t y]=ode45(@(t,y)rxn(t,y),timespan,y0);

Answer 1

[Matt J]

Well, for example dXadt is 1x2 and dXedt is 1x1, so you cannot stack them on top of each other to form a new matrix.

dXadt =

   1.0566e+07


dXadt =

   1.0e+07 *

    1.0566    1.0566


dXbdt =

   1.0566e+07


dXbdt =

   1.0e+07 *

    1.0566    1.0566


dXcdt =

   1.0566e+07


dXcdt =

   1.0e+07 *

    1.0566    1.0566


dXddt =

   1.0566e+07


dXddt =

   1.0e+07 *

    1.0566    1.0566


dXedt =

        1340


dXfdt =

       13400


dXgdt =

        1340

Answer 2

[Stephan]

f=[dXadt'; dXbdt'; dXcdt'; dXddt'; dXedt; dXfdt; dXgdt]