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exitFlag meaning in GA solver

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Hello everyone,
I just wanna ask a question about the meaning of some extFlags in Genetic Algorithm solver. Not exactly the meaning, I know that it is written clearly in the documentation of this solver. But, which one of the exitFlag is the favorable one, indicating a good set of solutions? For example, when I run the same code 50 times, sometimes the exitFlag is 0, sometimes is -2.
Could someone please clarify this for me?
I would really appreciate your help. and thank you so much in advance.


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Accepted Answer

Gifari Zulkarnaen
Gifari Zulkarnaen on 13 May 2020
As I know, good solution is when it converges, the change of few last iteration does not improves (exit flag 1, 3). Or when solution meets your specified value (exit flag 5).
And not so good solution is if it stops due to max time/iteration (exit flag 0, -4, -5), means it may not converge. It may gives better solution when you increase those limits. Or when the solution change is smaller than matlab capability (exit flag 4), this means you may need to improve your objective function.
Clearly bad solution is when no solution is found (exit flag -2).


Walter Roberson
Walter Roberson on 13 May 2020
Positive values: ga figures it did a reasonably good job, that there is specific reason to stop running
-2: you definitely did not get a useful answer
Otherwise: ga thinks there is a possibility that you might get a better solution if you let it ran longer. It is not seeing specific reasons in the function values to stop, but it ran into a resource limit that you set up.
Hoang Trinh
Hoang Trinh on 16 May 2020
Thank you so much for your answers. I have better understanding now ^^.

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