Why my function do not work and gives me an error message?

function [y] = SEM(x)
% Find out the each column of standard error for a matrix
%    x should be a nxm matrix or 1xm
y = nanstd(x)./sqrt(length(x) - sum(isnan(x)));
disp(y);
end

Command window:
>> x=weightm;
>> y=SEM(x)

Subscript indices must either be real positive integers or logicals. Error message: Subscript indices must either be real positive integers or logicals.

[Morteza Hajitabar Firuzjaei]

Dear friend,

you used indices, you should make sure you are using integers as indices or make sure you are using vectors or matrices

best wishes

Morteza Hajitabar Firuzjaei

Answer 1

[Guillaume]

Most likely, you have a variable called SEM in your workspace which shadow your SEM function. Hence you're indexing that variable instead of calling the function. Get rid of that variable or rename it.

Note that your sem function will give incorrect results for matrices that have more columns than rows because of the use of length. I would strongly recommend replacing length(x) by size(x, 1) but that is irrelevant for your error.

[AN NING]

Thank you, you are right, I changed the SEM into SEMM and the problem is solved.

Answer 2

[Morteza Hajitabar Firuzjaei]

Dear friend,

you used indices, you should make sure you are using integers as indices or make sure you are using vectors or matrices

best wishes

Morteza Hajitabar Firuzjaei