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Topic: Problem with "lsqnonlin" function in matlab
Replies: 6   Last Post: Sep 10, 2011 8:05 AM

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Torsten

Posts: 1,459
Registered: 11/8/10
Re: Problem with "lsqnonlin" function in matlab
Posted: Aug 30, 2011 6:31 AM
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On 30 Aug., 09:34, "fsalehi " <fsal...@gmail.com> wrote:
> I  have a problem with 'lsqnonlin' function in matlab. I used it to optimizing this function:
>
>     objfun = @(z) y - ( z(5).*exp(-z(1).*(t-z(7)).^2).*cos(2*pi.*z(2).*(t-z(7))+z(3)) + z(6).*exp(-z(1).*(t-z(8)).^2).*cos(2*pi.*z(2).*(t-z(8))+z(4)) );
>
> % y is my signal and I optimize a guassian pulse function for Model Base Estimation
>
> options = optimset(options, 'MaxFunEvals', 10000, 'TolX', 1e-3, 'TolFun', 1e-2, 'MaxIter', 800, 'LargeScale', 'on', 'LevenbergMarquardt', 'on', 'DiffMaxChange', 1e-7, 'DiffMinChange', 1e-10, 'Display', 'off', 'Diagnostics', 'off');
>
>     [Z,q,w,e,r]=lsqnonlin(objfun,...
>     [alpha         Fc       amptf(1:4) phase phase],...
>     [alpha-(2e6)^2 Fc-(2e6) toll(1:4)  []    [] ],...        
>     [alpha+(2e6)^2 Fc+(2e6) tolu(1:4)  []    [] ],options);        
>
> the problem is the result of optimization, I have 8 variable to optimizing, but in result Z, only 7 of them changes and one of them (alpha) doesnt change.
>
> why this happend?!


Do you start with a value of alpha = 1.749262265091693e+013 ?
Then evaluate your objfun for this value and see what you get for exp(-
alpha*...) ...

Best wishes
Torsten.





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