Comments on: Timing code in MATLAB

By: Arkajit Dey

Arkajit Dey — Thu, 18 Nov 2010 15:48:28 +0000

Thanks for the video. It was very useful. Also, here’s an easier way to time quick actions like Tim’s ‘dosomething’:

>> tic; dosomething; t = toc

–Arkajit

By: Doug

Doug — Fri, 15 Feb 2008 13:42:03 +0000

Tim, an excellent suggestion. I would want to make sure that the time for dosomething >> the rest of the code in loop. For most applications it would be.

Thanks,
Doug

By: Tim Davis

Tim Davis — Fri, 15 Feb 2008 12:16:55 +0000

Sometimes you want to time code that runs for a teeny fraction of a second, and

tic ;
dosomething ;
t = toc

is not accurate. The profiler will also be inaccurate. (You might want to time this teeny fraction of a second becaus you want to use the dosomething function zillions of times inside a larger application). Here is a trick I like to use

tic ;
t = 0 ;
ntrials = 0 ;
while (t < 1)
dosomething ;
ntrials = ntrials + 1 ;
t = toc ;
end
t = t / ntrials ;

That way, you run “dosomething” enough times to accumulate a whole second, and then you compute the average time per call to dosomething.