Undefined function for input arguments of type 'double'

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.

Answer 1

[Geoff Hayes]

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.

[Stefania]

Many Thanks, Geoff! The file name was, indeed, the problem. I wasn't aware that it must perfectly match the function name in order to work properly.

[Geoff Hayes]

Glad that it worked out!

[jithin jayasingh]

i have met with the same error in my program today.And it was your answer Mr. Geoff Hayes that help me to sort it out. you are a superhero Mr.Hayes and thanks for your answer.....

[Jozef Duda]

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]

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

Answer 2

[Jithin Nambiar J]

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 !!

[Gizem Deniz Akkas]

thank you!!