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));
