MATLAB: How to keep track of last change in a variable inside the loop

forfor looploopMATLABvariable

Suppose I have a variable NN, and I am applying for loop 40 times….each loop may or may not change the variable NN….I want to know what is the last loop where the variable NN changes….for example:if the last change of NN occurs at 35th loop and no changes thereafter then, how should I know that it last changes at 35th loop by using the code?… can anyone help

Best Answer

You can keep track of NN and then compare it to the prior one and log when it changes.
lastNN = -999999; % Something you know it will never be.
indexOfLastChange  = 1;
for k = 1 : 40
    NN = GetNewNN(k);  % Somehow get a new NN, or maybe not!
    % Now compare this NN to the prior one.
    if NN ~= lastNN
        % It changed!  Log it
        indexOfLastChange = k;
    end
    % Save the current NN as the last one:
    lastNN = NN;
end
% Notify user of the time it last changed.
message = sprintf('NN last changed during iteration %d.', indexOfLastChange)
uiwait(helpdlg(message));
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