Unable to Understand error: left and right side elements do not match

Here is my code to solve and ODE given by the function O_Hydrogen(~,C,japp,alpha,params) in the code, after running i keep getting the same error. I am unable to understand why ? Could anyone please explain.

clc 
%% Parametrs Set of Electrochemical Cell 
params.Volume= 0.0005; % m3
params.ElecArea= 87.6e-04; % m2
params.Masstransfercoefficient= 5.2e-05;% m/s
th=input("Input Time in hours ");
tend= 60*th; % Time in Seconds 

%% Initial Values
C0=0.625; % mole O2 / m3 
H0=0;  % mole H2/m3
yi=[C0;H0;0];
jlim_0 = j(C0,params); % A/m2 
japp = input("Input applied current density"); % A/m2

%% Calculation of critical time and crtical COD 
alpha=japp/jlim_0; % Dimensionless 
Cr=alpha*C0; % Critical COD mole O2 / m3
tcr= ((1-alpha)/alpha)*params.Volume/(params.ElecArea*params.Masstransfercoefficient); % Seconds 

%% Determination of step size 
% Number of points to plot 
n=100; 
dt1=2*tend/(n);
dt2=2*(tend-tcr)/(n);
dt3=tcr/n;
trange=0:dt3:tcr;
trange2=tcr:dt2:tend; 
trange_H = 0:dt1:tend; 
%% Equation solving 

% [t1,C1]=ode45(@(t,C)COD(t,C,alpha,params),trange_H,C0);
% 
% [t2,C2]=ode45(@(t,C)COD(t,C,alpha,params),trange2,Cr);   
% 
% [t,H]=ode45(@(t,H)Hydrogen(t,japp,params),trange_H,H0);

%% Test ODE 
[t,Cc] = ode45(@(t,C)O_Hydrogen(t,japp,C,alpha,params),trange_H,yi);


%% Append All data
% [CC]=[C1;C2];
% [T]= [t1;t2];

%% Plot Data 
% figure 
% plot(T,CC); 
% figure
% plot(t,H);

%% Calculation of limiting current Density 
function jlim= j(C,params)
km=params.Masstransfercoefficient;
jlim = 4*96500*km*C;
end 

%% Anodic Pollutant Oxidation  Charge Control 
function dCdt=COD(~,C,alpha,params)
a=alpha;
Vr=params.Volume; 
A=params.ElecArea; 
km=params.Masstransfercoefficient;
dCdt=zeros(1,1);
dCdt(1)=C(1)*(-a)*A*km/Vr ; % mol COD/s 
end 

%% Cathodic Hydrogen Genreanration 
function dHdt=Hydrogen(~,japp,params)
A=params.ElecArea; % m2;
Vr=params.Volume; % m3;
j=japp; %A/m2
F=96500;
dHdt=zeros(1,1);
dHdt(1)=(j*A/(2*F*Vr)); % mol H2/s
end 

%% Hydrogen production due to pollutant oxidation 
function dOHdt=O_Hydrogen(~,C,japp,alpha,params)
a=alpha;
Vr=params.Volume; 
A=params.ElecArea; 
km=params.Masstransfercoefficient;
F=96500;
j=japp; 
dOHdt=zeros(3,1);
dOHdt(1)=C.*(-a)*A*km/Vr; % mol COD/s 
dOHdt(2)= j*A/(2*F*Vr) ;  % mol H2/s Hydrogen Production from Electrolysis 
dOHdt(3) = 36.*dOHdt(1); % mol H2/s due to organics oxidation
end 

[Sam Chak]

@Ranjeev Kumar Bhatia

Can you format the MATLAB Code for %parameters, %ODEs, %solver, and %plotting?

[Ranjeev Kumar Bhatia]

Hi,

Thank you for your reply,

would you like me to uncomment them ?

[Ranjeev Kumar Bhatia]

maybe i do not understand.

Could you please clarify ?

[Torsten]

[t,Cc] = ode45(@(t,C)O_Hydrogen(t,japp,C,alpha,params),trange_H,yi);
function dOHdt=O_Hydrogen(~,C,japp,alpha,params)

@Ranjeev Kumar Bhatia

Do you see that the order of the input parameters to O_Hydrogen is swapped in its call compared with the routine itself ?

[Ranjeev Kumar Bhatia]

Hi ,

Still get the same error.

[Ranjeev Kumar Bhatia]

Hi everyone,

Thank you for the feedback. It managed to work.

Much appreciated.

Corrected Code

clc 
%% Parametrs Set of Electrochemical Cell 
params.Volume= 0.0005; % m3
params.ElecArea= 87.6e-04; % m2
params.Masstransfercoefficient= 5.2e-05;% m/s
th=input("Input Time in hours ");
tend= 60*th; % Time in Seconds 

%% Initial Values
C0=0.625; % mole O2 / m3 
H0=0;  % mole H2/m3
yi=[C0;H0;0];
jlim_0 = j(C0,params); % A/m2 
japp = input("Input applied current density"); % A/m2

%% Calculation of critical time and crtical COD 
alpha=japp/jlim_0; % Dimensionless 
Cr=alpha*C0; % Critical COD mole O2 / m3
tcr= ((1-alpha)/alpha)*params.Volume/(params.ElecArea*params.Masstransfercoefficient); % Seconds 

%% Determination of step size 
% Number of points to plot 
n=100; 
dt1=2*tend/(n);
dt2=2*(tend-tcr)/(n);
dt3=tcr/n;
trange=0:dt3:tcr;
trange2=tcr:dt2:tend; 
trange_H = 0:dt1:tend; 
%% Equation solving 

% [t1,C1]=ode45(@(t,C)COD(t,C,alpha,params),trange_H,C0);
% 
% [t2,C2]=ode45(@(t,C)COD(t,C,alpha,params),trange2,Cr);   
% 
% [t,H]=ode45(@(t,H)Hydrogen(t,japp,params),trange_H,H0);

%% Test ODE 
[t,Cc] = ode45(@(t,C)O_Hydrogen(t,C,japp,alpha,params),trange_H,yi);


%% Append All data
% [CC]=[C1;C2];
% [T]= [t1;t2];

%% Plot Data 
% figure 
% plot(T,CC); 
% figure
% plot(t,H);

%% Calculation of limiting current Density 
function jlim= j(C,params)
km=params.Masstransfercoefficient;
jlim = 4*96500*km*C;
end 
%% Anodic Pollutant Oxidation  Charge Control 
function dCdt=COD(~,C,alpha,params)
a=alpha;
Vr=params.Volume; 
A=params.ElecArea; 
km=params.Masstransfercoefficient;
dCdt=zeros(1,1);
dCdt(1)=C(1)*(-a)*A*km/Vr ; % mol COD/s 
end 
%% Cathodic Hydrogen Genreanration 
function dHdt=Hydrogen(~,japp,params)
A=params.ElecArea; % m2;
Vr=params.Volume; % m3;
j=japp; %A/m2
F=96500;
dHdt=zeros(1,1);
dHdt(1)=(j*A/(2*F*Vr)); % mol H2/s
end 

%% Hydrogen production due to pollutant oxidation 
function dOHdt=O_Hydrogen(~,C,japp,alpha,params)
a=alpha;
Vr=params.Volume; 
A=params.ElecArea; 
km=params.Masstransfercoefficient;
F=96500;
j=japp(1); 
dOHdt=zeros(3,1);
dOHdt(1)=C(1).*(-a)*A*km/Vr; % mol COD/s 
dOHdt(2)= j*A/(2*F*Vr) ;  % mol H2/s Hydrogen Production from Electrolysis 
dOHdt(3) = 36.*dOHdt(1); % mol H2/s due to organics oxidation

end 

Answer 1

[Spectro]

I think you should replace in the O_Hydrogen function this:

j=japp; 

with this:

j=japp(1);

[Ranjeev Kumar Bhatia]

Hi,

changed but i still get the same error