MATLAB: When I try to run a function in matlab, I get an error, it is undefined

Question

I have the following code:

M=[1 2 3; 4 5 6 ; 7 8 9]

function [result] = checkEchelonMatrix(M)

% M – input matrix to test

M=[1 2 3; 4 5 6 ; 7 8 9]

%rest of my code is here

end

When I try to run my function

checkEchelonMatrix(M) I get the following error:

>> matrixcheck(M)

Undefined function or variable 'M'.

Answer 1

Put this code in a file called checkEchelonMatrix.m that is on the MATLAB path:

function [result] = checkEchelonMatrix(M)
%rest of my code is here
end

Then have other code somewhere else that calls it. E.g., at the command line:

M=[1 2 3; 4 5 6 ; 7 8 9];
checkEchelonMatrix(M);

Do not simply push the "green run" button inside the editor ... that simply runs the code with no inputs.