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The problem of initial parameters in Lsqcurvefit

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CHOI HYUNDUK
CHOI HYUNDUK 2018-11-25
编辑： CHOI HYUNDUK 2018-11-26
I have a problem in Lsqcurvefit.
I am optimizing Boucwen Model with lsqcurvefit.
But when it runs with the initial parameters of below, it says
"Matrix dimensions must agree. Error in lsqcurvefit/objective (line 265)
F = F - YDATA; "
a = [1,1,1,1,1,1];
But if i use this initial parametes of below by looking for manually, it works well .
a = [12,5966,29,147,538,245];
Since I have 300 datas, I can't find each initial parameters.
So I read two ways of below such as exitflag, output and optimooptions.
I dont understand well which things are good for mine, So could you give me the recommendations for solving this problem?
Thank you so much.
https://www.mathworks.com/help/optim/ug/lsqcurvefit.html#buuhcjo_sep_shared-exitflag
https://www.mathworks.com/help/optim/ug/optimoptions.html

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Matt J
Matt J 2018-11-25
编辑：Matt J 2018-11-25
So could you give me the recommendations for solving this problem?
Check the output of predicted(). Make sure it has the same dimensions as ydata2.
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Matt J
Matt J 2018-11-26
force predicted is interpolated. But ydata is not interpolated.
Isn't it? What is this line doing in your code?
ydata2 = interp1(time, ydata,t,'spline');
CHOI HYUNDUK
CHOI HYUNDUK 2018-11-26
编辑：CHOI HYUNDUK 2018-11-26
When it is optimized
lsqcurvefit(predicted,a,t,ydata2);
here, predicted funtion gives output interpolated by random time span.
So, it needs to fit same vector between predicted output and ydata.
I made 't function' additionaly for getting 't' number for interpoltating ydata to ydata2.
But I think now, t function just is get 'initial parameter' just one time.
therefore, ydata2 has always same vector.
However, predicted output vector is changed depends on 'parameters optimizing in real time'.
I wonder how can i fix this error.
The more initial parameters are close at parameters that i want, it works well without problem coincidently.

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