Undefined function for input arguments of type 'double' - fit function

I'm running the following code:

close all
clear
clc

x = [0:0.01:1];
A=[0.0; 0.2; 0.4; 0.6; 0.8; 1.0];
B=[0.0; 0.034; 0.12; 0.267; 0.5; 1.0];

f=fit(A,B,'poly2')

But it results in the following error:

Undefined function 'fit' for input arguments of type 'double'.

Error in filename (line 68)
f=fit(A,B,'poly2')

I checked that the folder is in the correct path.

Help is appreciated.

Answer 1

[Guillaume]

Most likely you don't have the curve fitting toolbox installed or you don't have a license for it.

[madhan ravi]

+1 right point

[Guillaume]

I do have it installed: Statistics and Machine Learning Toolbox Version 11.3 (R2018a)

fit is part of the Curve Fitting Toolbox not the Statistics toolbox.

[madhan ravi]

True..

[Jochem]

Thanks for the help.

It was indeed the Curve Fitting Toolbox that wasn't installed. No idea why it wasn't installed, because it's part of the standard suite.

[Georgios Tsimplis]

I did it !!!! it works! thanks for your help!

[madhan ravi]

Georgios isn’t that what I told you in your question?

Answer 2

[madhan ravi]

What does the below show?

which fit -all
whos fit

[Jochem]

C:\Program Files\MATLAB\R2018a\toolbox\stats\stats\@gmdistriution\fit.m % gm distritbution method

[madhan ravi]

You are missing two files:

/Applications/MATLAB_R2018b.app/toolbox/curvefit/curvefit/fit.p
/Applications/MATLAB_R2018b.app/toolbox/curvefit/curvefit/fit.m  

Two options you have got now:

1) As Guillaume says either you would not be having Curve Fitting Toolbox installed or have a license for it , so you will have a question how to check those:

ver % in command window , check whether you have Statistics and Machine Learning Toolbox
license('checkout','Curve_Fitting_Toolbox') % if it returns 1 then you have a valid license

2) If the first option fails get the two files by contacting the Mathworks Support Team by clicking the Contact Us button on the top right corner of this page.

EDIT : Sorry Guillaume didn't notice your answer properly.

[Jochem]

I do have it installed:

Statistics and Machine Learning Toolbox Version 11.3 (R2018a)

[madhan ravi]

So just follow my second option .