When i saved my code , I am getting this error "Undefined function 'X0' for input arguments of type 'double'". Why is that?

Tb0 =100; 
Tvc =110; 
% initialisation du débit de la vapeur de chauffage (Mvc) en [kg/s] 
x0(5*n+1)=((Uh*Ah)/Ls)*((Tb0-x0(4*n))/log((Tvc-x0(4*n))/(Tvc-Tb0)));

Answer 1

[michio]

x0 in your code is a variable or a function? The error message says that x0 is not defined.

[ahlem sellami]

x0 is a variable

[michio]

Hm, no clue at the moment. Could you provide a sample code that I can actually run in my end and that reproduces the same error?

It would be much easier to help you here.

[ahlem sellami]

fprintf('* Données de l installation \n'); 
fprintf('--------------------------- \n');
n=input(' Nombre des étages: n =21 '); 
Tb0=input('Température maximale de chauffage de la saumure, [°C]:T0 =100');
Tvc=input('Température de la vapeur de chauffage en [°C]: Ts =110');
% initialisation des inconnues du système d'équations
%initialisation de la température de l'eau à la sortie des condenseurs 
% (ti) en [°C]
for i=1:n    
    x0(4*n+i-1)=Tf+((n+1)-i)*dT1; 
end

% initialisation du débit de la vapeur de chauffage (Mvc) 
% en [kg/s] 
x0(5*n+1)=((Uh*Ah)/Ls)*((Tb0-x0(4*n))/log((Tvc-x0(4*n))/(Tvc-Tb0))); 
% initialisation du débit de l'eau d'alimentation (Mf) en [kg/s] 
x0(5*n)=(Ls/Cph)*(x0(5*n+1)/(Tb0-x0(4*n)));
Uh, Ah and Ls are data it
Error
Undefined function 'x0' for input arguments of type 'double'.
Error in 
x0(5*n+1)=((Uh*Ah)/Ls)*((Tb0-x0(4*n))/log((Tvc-x0(4*n))/(Tvc-Tb0)));

Answer 2

[Jan]

What is "Tf" and "dT1"? Did you notice that in the header of your question the name is "X0" with an uppercase X?

[ahlem sellami]

Tf and dT1 are data it and uppercase X is a fault Writing