lsqcurvefit is undefined in MathLab version R2007b
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Lieu-Kim Dang
el 16 de En. de 2022
Comentada: Mathieu NOE
el 17 de En. de 2022
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.
3 comentarios
Matt J
el 16 de En. de 2022
Max Heimann
el 16 de En. de 2022
Editada: Max Heimann
el 16 de En. de 2022
It seems to be part of the optimization toolbox.
https://mathworks.com/help/optim/ug/lsqcurvefit.html
Respuesta aceptada
Mathieu NOE
el 17 de En. de 2022
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);
2 comentarios
Rik
el 17 de En. de 2022
You do need to be aware that fminsearch is more sensitive to local minima than many other fitters in Matlab, or so I've heard.
Mathieu NOE
el 17 de En. de 2022
For those who want to go beyond fminsearch but still lack the optimization toolbox :
Más respuestas (2)
Lieu-Kim Dang
el 17 de En. de 2022
1 comentario
Rik
el 17 de En. de 2022
You posted this comment as an answer. Please use the comment section for comments, as the order of answers can change.
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