So, you simply cannot put those 500 lines of code inside a function? Or if not as a function, as a script m-file?
There is absolutely no need to copy the code and thus replicate it inline.
Essentially, you can just put it into a separate m-file. Call it my_code.m. Save that as a file. You would then call it essentially like this:
if par_sig==0
for ...
my_code
end
elseif par_sig==1
parfor
my_code
end
end
Now you can make any changes just once, editing the my_code function/script.
