Why the function "timeit" doesn't work correctly

Help_please

I have a problem in function timeit (also tic toc) in matlab R2016a , it dsesn't calculate the correct time , for exemple: the result supposed to be: 4,.... seconds but it gives always 0,3....(the same code give a correct answer but in Matlab 2014)

[Jan]

What is your question? It is not clear, why you expect a specific runtime. Without any details it is impossible to answer.

Answer 1

[Jan]

timeit and tic/toc measure the runtime. If they determine a runtime of 4 seconds in Matlab R2014 and just 0.3 seconds in Matlab R2016a, this means, that Matlab works faster for the concerned results.

Remember, that the new graphics engine HG2 was introduced in R2014b. Maybe tic/toc measures the time before a complicated figure is rendered. So insert a drawnow in your code.

As said alread: As long as you do not mention any details about the code, it is impossible to understand, why you assume a problem. Post some code, which reproduces the problem and a more explicit explanation is possible.

[Sihem]

I have programmed the genetic algorithm for a scheduling problem, i see that's a problem cause when i calculate the time with a chronometer it gives me 4 seconds !! not 0, ...

[Walter Roberson]

timeit() will usually run the function multiple times, in order to reduce measurement noise. (If the initial run takes more than a particular hard-coded amount of time then timeit() will just report that time rather than running several invocations.)

The design of the original timeit is discussed at https://blogs.mathworks.com/steve/2008/02/29/timing-code-in-matlab/

[Jan]

@Sihem: I have no idea how we can help you, if you insist on not explaining any details.