Doug’s MATLAB Video Tutorials

February 12th, 2008

Timing code in MATLAB

 It was about a year and a half ago when I posted about using the profiler to find bottlenecks in your MATLAB code [click here]. This week’s video covers two quick and easy ways of timing your code in MATLAB. This is how people would profile their code before the profiler, but it is still a useful set of tools to have. In response to the survey, I have obtained new audio recording equipment. Let’s hope you like the results.
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By Doug Hull

10:03 UTC | Posted in Format: PodCast, Format: Video, Level: Basic | Permalink |

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2 Responses to “Timing code in MATLAB”

  1. Tim Davis replied on February 15th, 2008 at 07:16 UTC :

    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.

  2. Doug replied on February 15th, 2008 at 08:42 UTC :

    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

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