lsqcurvefit is undefined in MathLab version R2007b

Question

Lieu-Kim Dang 2022-1-16

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1629895-lsqcurvefit-is-undefined-in-mathlab-version-r2007b

评论： Mathieu NOE 2022-1-17

采纳的回答： Mathieu NOE

Hello MathLab community,

I have copied follwong code from MathWorks example:

xdata = ...

[0.9 1.5 13.8 19.8 24.1 28.2 35.2 60.3 74.6 81.3];

ydata = ...

[455.2 428.6 124.1 67.3 43.2 28.1 13.1 -0.4 -1.3 -1.5];

fun = @(x,xdata)x(1)*exp(x(2)*xdata);

x0 = [100,-1];

x = lsqcurvefit(fun,x0,xdata,ydata)

Running this code gives following error:

??? Undefined function or method 'lsqcurvefit' for input arguments of type 'function_handle'.

Error in ==> Fitt_2 at 11

x = lsqcurvefit(fun,x0,xdata,ydata)

What is the problem in the code?

Can anybody help to solve?

I'm working with MathLab version R2007b.

Thank you.

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Matt J 2022-1-16

Lieu-Kim Dang comment moved here:

Hello Rik,

thank you for your advice. Which toolbox is needed?

Max Heimann 2022-1-16

编辑：Max Heimann 2022-1-16

It seems to be part of the optimization toolbox.

https://mathworks.com/help/optim/ug/lsqcurvefit.html

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Answer 1

Mathieu NOE 2022-1-17

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https://ww2.mathworks.cn/matlabcentral/answers/1629895-lsqcurvefit-is-undefined-in-mathlab-version-r2007b#answer_875890

在 MATLAB Online 中打开

hello

FYI, you can do basic curve fitting with fminsearch - without the optimization toolbox

clc
clearvars
x =  [0.9 1.5 13.8 19.8 24.1 28.2 35.2 60.3 74.6 81.3];
y =  [455.2 428.6 124.1 67.3 43.2 28.1 13.1 -0.4 -1.3 -1.5];
f = @(a,b,x) a.*exp(b.*x);
obj_fun = @(params) norm(f(params(1), params(2),x)-y);
sol = fminsearch(obj_fun, [0,0]);
a = sol(1);
b = sol(2);
xfit = linspace(min(x),max(x),100);
yfit = f(a, b, xfit);
figure;
plot(x, y, '+', 'MarkerSize', 10, 'LineWidth', 2)
hold on
plot(xfit, yfit, '-');
TE = sprintf('C = %0.2fe^{%0.3ft}',a, b);
text(x(3), y(3)*1.5, TE);