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Matlab I am trying to write a function on an M-file

  1. Aug 31, 2007 #1
    Hi All

    I am new with Matlab

    I am trying to write a function on an M-file; here is the script:

    function f = ali(x)
    f = - x(1) * x(2);
    A = [-1 -2 -2; 1 2 2]
    b = [0; 72]
    x0 = [10; 10; 10];
    [x,fval] = fmincon(@ali,x0,A,b)

    Whenever i run it i get the following message;
    input argument "x" is undefined

    So can anybody help

    Best Regards
  2. jcsd
  3. Aug 31, 2007 #2


    User Avatar
    Gold Member

    you have to define x when you call the function. How are you running the function?

    I would suggest using the command window and calling it with:

    f = ali(x)

    where x is whatever two numbers you want it to be.

    in your second line, you call x(1) and x(2) so there has to be two elements in x
    so at your command window, you could enter:

    f = ali([5 7]) where I've chosen 5 and 7 arbitrarily.
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