what is wrong with this while loop?

    function [Gj,Lj,Xij,Yij,Tj]=SR(N,Tj,Fl,Fg,Zij,Qj,TF,Pj)
%inicio
Fj=Fl+Fg;
[Gj,Lj]=MetodoSR(N,Fg,Fl);
Tj0=0;
k=0;
while (((Tj-Tj0)/Tj)^2)>=1e-10 && k<=100
    k=k+1;
    for k=1:N
        Tj0=Tj(N-1);
        Kij=ctteK1(Pj,Tj,N);
        %Conversion de C a F
        Xij=MatrizxijT(N,Fg,Fl,Gj,Kij,Zij);
        [Lj,Gj,Xij,Yij]=Flujos(N,Lj,Xij,Fg,Fl,Kij);
        Tj=Tj*1.8+32;
        TF=Tj*1.8+32;
        %Conversion de kmol a lbmol 
        [MatrizTH]=TH(N,Tj,Xij,Yij,Lj,Gj);
        [HFlj,HFgj]=THFeed(N,TF,Zij);
        [Tj]=Balance(N,Tj,Yij,Xij,Lj,Gj,Fj,HFlj,HFgj,Qj,MatrizTH);
    end
end

[madhan ravi]

provide all the datas for (N,Tj,Fl,Fg,Zij,Qj,TF,Pj) and all the functions and paste it here

[Giulliana Marin]

There are way too many functions. The code used to run normally until I added the loop, meaning I added this:

    Tj0=0;
k=0;
while (((Tj-Tj0)/Tj)^2)>=1e-10 && k<=100
    k=k+1;
    for k=1:N
        Tj0=Tj(N-1);
...
  end
end

Also, Tj is a vector.

Answer 1

[Walter Roberson]

    k=k+1;
    for k=1:N

The second of those two lines overwrites the variable 'k' referred to in the first of the lines. After the for loop, k will be left at the last value from the for loop, which is to say N . The while loop will be testing that value against 100. If N < 100, then k will never exceed 100.

[Giulliana Marin]

What should I do to fix it? delete the for? I just want the loop to run while (((Tj-Tj0)/Tj)^2)>=1e-10 && k<=100

[Walter Roberson]

We do not know if you want Tj0 to be repeatedly calculated for each k value. But yes, probably you should be deleting the "for k" loop.

[Giulliana Marin]

Well, the main variable is Tj, so the loop should continue running until the difference between Tj and the previously calculated Tj (I wrote it as Tj0) is less than 1e-10. Actually, I made a mistake because I had written >= and it's <=. It still doesn't work though

[Walter Roberson]

for k = 1 : 100
        Kij=ctteK1(Pj,Tj,N);
        %Conversion de C a F
        Xij=MatrizxijT(N,Fg,Fl,Gj,Kij,Zij);
        [Lj,Gj,Xij,Yij]=Flujos(N,Lj,Xij,Fg,Fl,Kij);
        Tj=Tj*1.8+32;
        TF=Tj*1.8+32;
        %Conversion de kmol a lbmol 
        [MatrizTH]=TH(N,Tj,Xij,Yij,Lj,Gj);
        [HFlj,HFgj]=THFeed(N,TF,Zij);
        [Tj]=Balance(N, Tj, Yij, Xij, Lj, Gj, Fj, HFlj, HFgj, Qj, MatrizTH);
  if abs((Tj-Tj0)/Tj) <= 1e-10; break; end
  Tj0 = Tj;
end

[Giulliana Marin]

I get this: Undefined function or variable 'Tj0'

[Walter Roberson]

That should not be the case, since you had

 Tj0=0;

before your loop.