The most straightforward way to do this is via a nested function call. You can define your MATLAB Function in a separate .m file, and then call that function from the MATLAB Function Block. See the example below:
% In the MATLAB Function Block code
function y = fcn(u)
y = foo(u);
end
% In a separate M file on the MATLAB Path:
function z = foo(x)
z = x^2;
end
Another way to achieve this workflow is to use a MATLAB Interpreted Function block, but this block does not support code generation at this time.
