measure time elapse for loop in matlab

To measure the time taken by a for loop in MATLAB, you can use the tic and toc functions. tic starts a timer, and toc stops the timer and returns the elapsed time. Here's an example:

main.m
n = 1000000;
tic
for i = 1:n
    % code here
end
elapsed_time = toc;
disp(['Elapsed time: ', num2str(elapsed_time), ' seconds']);
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In this example, we have a for loop that runs n times. We start the timer with tic, run the for loop, and then stop the timer and calculate the elapsed time with toc. Finally, we display the elapsed time as a message.

Note that tic and toc can have different scopes. This means that you can start the timer before the for loop and stop it after the loop, or you can start and stop the timer inside the loop to measure the time taken by each iteration. It all depends on what you want to measure.