Code not working, something with while loop

I think the error in my code is in the while loop, I don't think i and/or j are increasing their value.

E_n is the value that will give my my answer. I want i and j to start at 1, but when I do, E_n is 0 for all values. Then when I change the starting conditions, only a few numbers are non-zero, and they are all the same value. This is why I think my while loops are not working, which leads to my code not checking every element in the matrix M.

M_0 = [0, 30, 90, 135, 180, 200, 350;
       0, 30, 90, 135, 180, 200, 350;
       0, 30, 90, 135, 180, 200, 350;
       0, 30, 90, 135, 180, 200, 350];
M = M_0 .* (pi / 180);
 
e = [0.01;
     0.1;
     0.5;
     0.9];

% Initial Calculations

E = zeros(4,7);
error = 10;
i = 1;
j = 1;

    while j <= 4

        while i <= 7

            if M(j,i) > -pi && M(j,i) < 0
                E_n = M(j,i) - e(j);

            elseif M(j,i) > pi
                E_n = M(j,i) - e(j);

            elseif M(j,i) < pi && M(j,i) > 0
                E_n = M(j,i) + e(j); 

            else
                E_n = M(j,i);
            end

            while error >= 10^-6
                E_n_plus_1 = E_n + ((M(j,i) - E_n + e(j) * sin(E_n)) / (1 - e(j) * cos(E_n)));

                error = abs(E_n - E_n_plus_1);                
                E_n = E_n_plus_1;
            end

            E(j,i) = E_n_plus_1;        
            i = i + 1;
        end

        j = j + 1;
    end


M_deg = reshape(M_0,28,1);
E_deg = reshape(E,28,1);
e1 = [0.01;0.01;0.01;0.01;0.01;0.01;0.01;
      0.1;0.1;0.1;0.1;0.1;0.1;0.1;
      0.5;0.5;0.5;0.5;0.5;0.5;0.5;
      0.9;0.9;0.9;0.9;0.9;0.9;0.9];
  
table(M_deg,e1,E_deg)

[Zach Harrison]

Update: i and j values are 8 and 5 respectively and the end of the code so I guess that part works fine

Answer 1

[David Fletcher]

The counter for the inner i loop never gets reset back to it's initial value, so it will only run on the first iteration of the j loop. You will incidentally have the same problem with the error loop, as that never gets re-initialised after the loop either

[Zach Harrison]

With this change, my values are still all zeros. Also if this were my only issue, my first 7 values should be correct, but they are not.

while j <= 4
    i = i + 1;   %% Added this
    while i <=7

[David Fletcher]

...and also the error variable sice it's that loop that updates the E_n values

[Zach Harrison]

Thank you, that worked