Code not working, something with while loop

Question

Zach Harrison 2021-4-16

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/804346-code-not-working-something-with-while-loop

评论： Zach Harrison 2021-4-16

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)

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Zach Harrison 2021-4-16

编辑：Zach Harrison 2021-4-16

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

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Answer 1

David Fletcher 2021-4-16

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/804346-code-not-working-something-with-while-loop#answer_677086

编辑：David Fletcher 2021-4-16

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