lsqcurvefit is undefined in MathLab version R2007b

6 views (last 30 days)
Lieu-Kim Dang
Lieu-Kim Dang on 16 Jan 2022
Commented: Mathieu NOE on 17 Jan 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 Comments
Max Heimann
Max Heimann on 16 Jan 2022
It seems to be part of the optimization toolbox.
https://mathworks.com/help/optim/ug/lsqcurvefit.html

Sign in to comment.

Accepted Answer

Mathieu NOE
Mathieu NOE on 17 Jan 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 Comments
Mathieu NOE
Mathieu NOE on 17 Jan 2022
For those who want to go beyond fminsearch but still lack the optimization toolbox :

Sign in to comment.

More Answers (2)

Lieu-Kim Dang
Lieu-Kim Dang on 17 Jan 2022
Hello Mathieu,
many thanks for your valuable solution. I will try it out.

Lieu-Kim Dang
Lieu-Kim Dang on 17 Jan 2022
Hello Max,
thank you for your information. I'm contacting MAthLab to get the license for this toolbox.
  1 Comment
Rik
Rik on 17 Jan 2022
You posted this comment as an answer. Please use the comment section for comments, as the order of answers can change.

Sign in to comment.

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by