how to properly call a function in a separate m-file?

I have created the following function in a separate m-file called "fourierCompute.m"

function [Ck, Basis, t, x] = fourierCompute(tp, xp, delta_t, t_begin, t_end, T, N)
  k = -N:N;
  w0 = 2*pi/T;
  Basis = exp(1i * w0 * k.' * tp);
  Ck = (1/T) * int(xp * (exp(-1i * w0 *k * tp)), tp, -T , T);
  t = t_begin:delta_t: t_end;
  x = Ck * Basis;
end

In a separate m-file I am trying to call that function, but when I run it I get the messge "Undefined function or variable 'fourierCompute'." Both files are in the same location so I am not sure what is wrong. How do I properly call this function into a separate m-file? What am I doing wrong?

[Ck, Basis, t, x] =  fourierCompute(tp, xp, delta_t, t_begin, t_end, T, N);

[dpb]

The working directory is likely not the directory the files are located in and also not on MATLABPATH. Adding the location to the latter is probably the better solution if want these generally available; if only working on a temporary problem then

cd ThatDirectory

should solve it.

[bribee]

That worked, thank you so much.

[Julian Behrens]

@dbp I added the folder in which the .m file is, which contains the function I want to call. I want to call the function from another file in the same folder (so I guess same wd), but still I get the message of "Undefined function or variable ...". Why is that? What can I do?

[dpb]

Check spelling of both the file and the directory in the MATLABPATH

Only the primary function in an m-file has scope outside the m-file itself so if the one wanted to be called were a local or nested function, it will not be visible to an external function.

Answer 1

[Jan]

"Undefined function or variable 'fourierCompute'."

This means, that the fourierCompute.m is not found in the path or the current working directory.

Relying on the current working directory is prone to bugs. Remember that each callback of a GUI or a timer can call cd to change the folder unexpectedly. Prefer to use addpath(folder, '-end') or pathtool to insert the parent folder of the .m file to the path.

Check the existence of the file in the path:

path
which fourierCompute.m -all