Function requires more input arguments to run

My function is:

    function[fa]=speriamo(u)

    if (0<=u<pi/3)
        fa=1; end;
    if (pi/3<=u<2*pi/3)
        fa=1; end;
    if (2*pi/3<=u<pi)
        fa=-6*u/pi+5; end;
    if (pi<=u<4*pi/3)
        fa=-1; end;
    if (4*pi/3<=u<5*pi/3)
        fa=-1; end;
    if (5*pi/3<=u<2*pi)
        fa=6*u/pi-11; end;

    end

when I click "Run", the program give me error: "speriamo" requires more input arguments to run. Any other variable I would add is regarded as an unnecessary variable. It's a simple function, what am I doing wrong?

[Adam]

How exactly would you expect it to know what 'u' is if you just click 'Run' and don't supply it?!

[Cosimo Iurlaro]

'u' is an input variable, an angle in radians, but even if considered as a simple scalar variable, the function that I try to achieve is a function of the values determined at the input variable, associates an output. What should I add or change?

[Adam]

Both of the answers below work fine to solve the problem, I am just trying to get you to think logically about it so that you don't do the same thing again.

If the whole point of your function is to run some code based on an input parameter surely the first thing you should be thinking about when running the function is to be able to pass in that input parameter, otherwise what kind of results could you expect?

[Cosimo Iurlaro]

thank you very much.

Answer 1

[Geoff Hayes]

Cosimo - since this is a function that has one input parameter, then you need to supply that parameter. From the command line you would do

 >> [fa]=speriamo(42);

Pressing the RUN button (from the MATLAB file editor) will just call the function as

 >> speriamo

and not provide any input parameters. Hence the error.

[Cosimo Iurlaro]

thank you, very much.

Answer 2

[Steven Lord]

When you click Run you call your function with 0 input arguments. The way you have defined the function:

 function[fa]=speriamo(u)

it requires one input argument to run. See this page from the documentation for how to configure the Run button to run your function with an input argument, or call your function at the MATLAB command prompt (the >> or EDU>> prompt in the Command Window) with an input argument.

FYI, this line of code:

 if (0<=u<pi/3)

doesn't do what you think it does. If you're only going to run this code with a scalar (1-by-1) u then rewrite it as:

 if (0 <= u) & (u < pi/3)

If you're going to run this code with a nonscalar u, use logical indexing.

[Cosimo Iurlaro]

thank you, very much.

[jakkapally srinivas]

Do you even know what you have answered!

[Steven Lord]

Yes.