MATLAB: Speed up intersect, setdiff functions

intersectsetdiffvectorize

Hi
I have some code, which when I examine using the Matlab Profiler shows that the majority of the time is spent on the intersect and setdiff functions, which are invoked many times during a looping process. I was wondering if there was a clever way to speed this up? For example is it possible to somehow vectorize the following code to avoid invoking the inbuilt set functions? Thanks for your help!
tic;
size=50000;
a=round(100*rand(size,1));
b=round(100*rand(size,1));
intersect(a,b);
setdiff(a,b);
toc;

Best Answer

intersect and setdiff both sort the inputs. Therefore you can omit at least one sorting, when you copy the relevant parts of both function to a new file. Then ismembc will do its work once, as Sean has suggested already.
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