Problem fitting with lsqcurvefit

Question

Hussam Saddour 2022-9-12

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1803520-problem-fitting-with-lsqcurvefit

评论： Hussam Saddour 2022-9-13

Radiusverlauf.xlsx

im getting the following error while executing the code "Index exceeds the number of array elements (2)", the goal is to fit a curve to points using a certain Formula:

[name,path]=uigetfile({'*.xlsx'});
Error using matlab.internal.lang.capability.Capability.require
Support for Java user interfaces is required, which is not available on this platform.

Error in uigetfile (line 117)
Capability.require(Capability.Swing);
filename = [path name];
opts = detectImportOptions(filename);
preview(filename,opts);
newtable = readtable(filename);
x = newtable{:,1};
y = newtable{:,2};
fun = @(w,x) sqrt(w(1)^2+w(2)^2*(x-w(3))^2)
x0 = [1 1];
w = lsqcurvefit(fun,x0,x,y)

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Torsten 2022-9-12

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1803520-problem-fitting-with-lsqcurvefit#answer_1051780

在 MATLAB Online 中打开

M = [26 93

27 67.9

28 54.5

29 20.5

29.1 20.6

29.2 17.6

29.3 15.7

29.4 13

29.5 12

29.6 9.2

29.7 8.7

29.8 6

29.9 5.4

30 6.3

30.1 7.2

30.2 8.3

30.3 12.3

30.4 12.4

30.5 16.4

30.6 18.3

30.7 21.5

30.8 23.7

30.9 27.6

31 28.7

31.1 32.1

31.2 34.6

31.3 36.3

31.4 39.1

31.5 40.6

31.6 44.2

31.7 48.2

31.8 50.5

31.9 53.8

32 55.9

33 77.1];

x = M(:,1);

y = M(:,2);

fun = @(w) sqrt(w(1)^2+w(2)^2*(x-w(3)).^2);

fun2 = @(w)fun(w)-y;

w0 = [1 1 1];

w = lsqnonlin(fun2,w0)

Local minimum possible. lsqnonlin stopped because the final change in the sum of squares relative to its initial value is less than the value of the function tolerance.

w = 1×3

5.7432 24.9821 29.8623

hold on

plot(x,y,'o')

plot(x,fun(w))

hold off