How to use the OutputFcns function in the optimset options?

Question

Sheng Liu 2012-3-5

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/31188-how-to-use-the-outputfcns-function-in-the-optimset-options

Hi everybody!Now I'm using the fminsearch function in the optimization tool.For at here we

cannot upload a picture I have to describe it fully by characters. if you type 'doc optimset',you will see the help manual about the question I mentioned. you see the bold letters'option'?and the line 5,the OutputFcn?

OutputFcn

function | {[]}

User-defined function that an optimization function calls at each iteration.

fminbnd, fminsearch,fzero

as it was described,we can use a user-defined function to put out some other function called at

each iteration.

But ,it didn't give an example in detail,so how to use it ?could you please give an detailed

introduction of it?thank you so much!

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Answer 1

Seth DeLand 2012-3-5

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https://ww2.mathworks.cn/matlabcentral/answers/31188-how-to-use-the-outputfcns-function-in-the-optimset-options#answer_39665

http://www.mathworks.com/help/techdoc/math/bsgpq6p-23.html

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Sheng Liu 2012-3-6

OK!thank you so much!I've happened to find the same page that you pointed out,haha~~

And still a little question:

with this example changed something,just like this(for I don't need the history variable):

function [x fval] = myproblem1(x0) options = optimset('OutputFcn', @myoutput,'Display','iter');

[x fval] = fminsearch(@objfun, x0,options);

function stop = myoutput(x,~,state)

stop = false;

if state == 'iter'

disp([' x = ',num2str(x)]);

end

%disp(sprintf('\n\n'))

end

function z = objfun(x)

z = exp(x(1))*(4*x(1)^2+2*x(2)^2+x(1)*x(2)+2*x(2));

end

and then I input the commmand:

[x fval] = myproblem1([-1 1])

it did give a right result.

but if you input：

objfun(x)

it comes out like this:

> objfun(x)

ans =

0.3344

I don't understand,doesn't the return value of the fminsearch function equal to the minimum value of objfun(x)?So,why doesn't the ans above equal to -0.5689,as written in the help page you mentioned?

Thank you!!!!

my question is,i

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