Fill a matrix with a while loop and generate a convergence criteria

Hello,

i have a problem with loops and matrices. I want to program an iteration with a while loop where i calculate several values which depend on each other. One value act's as a convergence criterium and therfore i thought it would be smart to store it in a matrix. My problem now is that i don't know how i get the current and the previous value from the matrix. With these two values i want to check the convergence criterium each iteration. (The iteration process is for the analytical calculation of a knurled press connection)

myMatrix = [1,1]; % create matrix
while diff > 1 
    % here are the calculations
    .
    .
    .
    .
    
    
    p_v = F_rad/(2 * pi * r_ai * l_f);  % calculation for the convergence criterium
    
    for 
    reslut_0 = Matrix(end,end); % second last value
    myMatrix = [myMatrix, p_v]; % expand matrix
    result_1 = Matrix(end,end); % last value
    diff = result_1 - result_0;
    end 
end

I thought it would be clever to do the convergence check with a for loop. But honestly i don't know which condition it should apply. Maybe anyone could help me out. I saw through the documentation but it didn't really helped me.

Thanks in advantage

[Stijn Haenen]

I think you should change to order of your code to:

reslut_0 = Matrix(end,end); % second last value
myMatrix = [myMatrix, p_v]; % expand matrix
result_1 = Matrix(end,end); % last value

[Lennard Schulze]

Okay thanks for that advice. Is the whole storage operation with the matrix correctly listed?