While loop with for loop problem

Hello everyone!

I have a situation here trying to solve a while loop inside a for loop.

As you can see in the code, I want to calculate "xn", varying "omega" and then, evaluate which "omega" gives the minor number of iterations (nite), storing in a vector (nite_vec) the each "nite" for each "omega" used in the looping.

But the counte "i" does not to up date inside the "while".

%% Iterations
    D = [3 0 0; 0 2 0; 0 0 1];
    b = [0; 1; 0];
    L = [0 0 0; 1 0 0; 0 1 0];
    U = [0 1 0; 0 0 1; 0 0 0];
    tol = 10^-7;
    nite_max = 100;
    n = length(b);
    x0 = zeros(n,1);
    omega = (1:0.05:2)';
    nite = 0;
    xn = 1;
    xi = x0;
    
    for i = 1:length(omega)   
       while norm(xn-xi) >= tol && nite <= nite_max
            xn = (D-omega(i)*L)\((1-omega(i))*D+omega(i)*U)*x0+omega(i)*((D-omega(i)*L)\b);
            xi = x0;
            x0 = xn;
            nite = nite+1;
       end
       nite_vec(i) = nite;
    end

Could anyone help me with this!

Many thanks!

Answer 1

[Stephen23]

Perhaps you meant something like this:

D = [3 0 0; 0 2 0; 0 0 1];
b = [0; 1; 0];
L = [0 0 0; 1 0 0; 0 1 0];
U = [0 1 0; 0 0 1; 0 0 0];
tol = 10^-7;
n = numel(b);
nite_max = 100;
omega = 1:0.05:2;
for k = 1:numel(omega)
    nite = 0;
    x0 = zeros(n,1);
    xn = 1;
    xi = x0;
    while norm(xn-xi)>=tol && nite<=nite_max
        xn = (D-omega(k)*L)\((1-omega(k))*D+omega(k)*U)*x0+omega(k)*((D-omega(k)*L)\b);
        xi = x0;
        x0 = xn;
        nite = nite+1;
    end
    nite_vec(k) = nite;
end

Giving:

>> nite_vec
nite_vec =    41    36    32    28    24    19    16    17    20    22    25    29    34    40    48    58    75   101   101   101   101

[José Everardo Baldo Junior]

Hello Stephen!

That's it! Many thankls for your help!!!

Kind regards,

Junior.