Undefined function 'piecewise' for input arguments of type 'double'.

Question

Problem :

I am very new to Matlab. I have written below code in my .M file:

function f = piecewise(w, C)
S=sqrt(diag(diag(C)));
s=diag(S);
f=sqrt(w'*C*w)/(w'*s);

I have already stored my file (piecewise.M) in my normal Matlab path, and so my assumption is that the Matlab will read my function when it will start and so my function must be available to be used.

But when I type below command

>> piecewise(w, C)

I start facing below error.

“Undefined function 'piecewise' for input arguments of type 'double'.”

Can you please help me in fixing above error?

Answer 1

I think your problem is most probably the problem related to path of your function file not present in the Matlab's 'path'.

So to verify this you just need to open your function in your Editor and then you should press the F5 key. It will make your Editor to try and run your file and if your file is not in the path then it will surely prompt you with the message box. Like Choose Add to Path in that and after that you must be fine to go

And from now onwards you will be able to use your function from your command line giving a correct set of arguments.