Undefined function for input arguments of type 'double'

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I have this set of data
x=[0:0.01:1];
y=4- 3*x + sin(x*6*pi) + rand(1,101)/8;
plot(x,y,'ko','MarkerFaceColor','k');
and want to do a fit using fminsearch
hold on
b0=[2,-2,2,5];
b=fminsearch(@(b) doamne(b,x,y), b0);
yfit= b(1)+ b(2)*x + b(3)*sin(x*pi*b(4));
plot(x,yfit, '-b')
hold off
where
function d2=doamne(b,x,y)
c2=y- (b(1)+ b(2)*x)
d2=sum(c2.^2)
but I keep getting this error: "Undefined function 'doamne' for input arguments of type 'double'." I double checked that all my files are in the working folder and that the working folder is in the path list but the error persists.

Accepted Answer

Geoff Hayes
Geoff Hayes on 10 Nov 2014
Stefania - in the Command Window, type
which doamne -all
to find the path to your doamne function. Perhaps you have named the m file for this function incorrectly, and so it cannot be found.
I was able to take the doamne function and copy and paste its code into a file named doamne.m and then could run the remainder of your code without error.
  5 Comments
Jozef Duda
Jozef Duda on 21 Mar 2017
I've also met similar error when clearing workspace from data acquired with Data Acquisition Toolbox. The error function was 'stop'. The solution was to find the 'stop' function, copy it in to the new file and name it stop.m and save it in current folder. After that operation the error information stopped to appear in the command window. Really thanks for this answear.
sam Boadi
sam Boadi on 24 Aug 2018
Possibly, you are using a different function name to call another function. Check to see that the name you are using to call the function is the same as the function name. I think this should also help

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More Answers (1)

Jithin Nambiar J
Jithin Nambiar J on 10 Apr 2021
It sometimes gives you this error if you don't have the right toolboxes installed for the certain function.
If a particular function is causing an error. Try typing
help functionName
If this results in like a certain toolbox is required for this function to work. Just click on the hyperlink or underlined link which is given in the terminal.
It will direct you to the appropriate package. Make sure you save any programs. Since installing the packages requires MATLAB to restart.
Cheers !!

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