GA options stall vs tolerance

Question

Mo 2015-1-14

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/169913-ga-options-stall-vs-tolerance

评论： Mo 2015-1-15

What is the difference between StallTimeLimit and TolFun. I think I know what they are in principle, but in the documentation they have identical descriptions. Also is the tolerance applied to successive raw fittest values, or are they scaled etc.?

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Alan Weiss 2015-1-14

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/169913-ga-options-stall-vs-tolerance#answer_164850

According to the documentation, "The algorithm stops if the average relative change in the best fitness function value over StallGenLimit generations is less than or equal to TolFun." If you don't understand what this means, take a look at How the Genetic Algorithm Works.

Alan Weiss

MATLAB mathematical toolbox documentation

3 个评论
显示 1更早的评论隐藏 1更早的评论

Alan Weiss 2015-1-14

Oh, you either have nonlinear constraints or an integer-constrained problem. To encourage ga to continue, set TolFun to a small value, maybe 1e-10 or 1e-12.

If you have integer constraints, there might be no other help but to play with options (and make sure your bounds are as tight as possible). But for nonlinear constraints, I uuge you to try patternsearch instead of ga. You will almost certainly get more reliable answers, and more quickly, too.

Alan Weiss

MATLAB mathematical toolbox documentation

Mo 2015-1-15

Indeed. Haven't checked the full results, but PS does at least appear to get solutions with reduced fitness penalty function much faster than GA. Orders of magnitude faster.

Thanks.

请先登录，再进行评论。