Calculating and and recording a vector during each iteration of a "while" loop.

Question

Wojciech Polyn 2021-4-7

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/795537-calculating-and-and-recording-a-vector-during-each-iteration-of-a-while-loop

编辑： James Tursa 2021-4-7

I have searched the forums for similar answered questions and tried the solutions, but I unfortunately I can't get any of them to work for me.

(...)

lambda = 1;
lambda0 = 2;
while abs(lambda0 - lambda) > (1*10^-6)
    R = M * R;
    R = R / norm(R,1);
    lambda0 = lambda;
    lambda = R' * M * R / (R' * R);
end
 Rfinal = R;

I've performed a while loop during which, through iterations, I reach a final set of values saved as vector "R". The final vector "R" is saved as "Rfinal".

Afterwards, in each iteration of that previous while loop, I need to record the values of

as "power_err" using the "R" of the current iteration. This will allow me to plot log10(power_err) for the iterations.

I'm unable to write a proper code to fulfil that task. Any help is appreciated.

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Answer 1

James Tursa 2021-4-7

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/795537-calculating-and-and-recording-a-vector-during-each-iteration-of-a-while-loop#answer_669662

编辑：James Tursa 2021-4-7

在 MATLAB Online 中打开

E.g., using a counter to store all of your iteration data in a cell array and then post process this:

k = 1; % the counter
Rcell = cell(1,1000); % some size larger than you expect
Rcell{1} = R;
while abs(lambda0 - lambda) > (1*10^-6)
    R = M * R;
    R = R / norm(R,1);
    lambda0 = lambda;
    lambda = R' * M * R / (R' * R);
    k = k + 1;
    Rcell{k} = R; % store current R in cell array
end
Rfinal = R;
power_err = zeros(1,k);
for x=1:k
    power_err(x) = your calculation here involving Rfinal and Rcell{x}
end