Question

I am trying to make my own function in matlab to solve for a system of two nonlinear equations, while using a nested function to share some some parameters, here is a sample code:

function y=solve(a,x0)
a;
y=fsolve(nle,x0);                       % this is line 3

    function f=nle(x)
        f(1)=x(1)-a*x(1)^2-x(1)*x(2);   % this is line 6
        f(2)=2*x(2)-x(2)+3*x(1)*x(2);
    end

end

Here a is the parameter I want to pass from command line to the function, and x0 is the start point for the fsolve.

However, when I call the function in malab after specifying a=4 and x0=[1 1]', it gave me the following error:

Error using solve/nle (line 6)
Not enough input arguments.

Error in solve (line 3)
y=fsolve(nle,x0);

I’m quite a newbie for matlab, can anybody tell me where I am doing wrong?

Thanks in advance.

EDIT:
I tried substituting the nle with a function handle @nle, but seems something else went wrong:

Undefined function 'fsolve' for input arguments of type 'function_handle'.

Error in solve (line 3)
y=fsolve(@nle,x0);

Doesn’t seem to make sense since I checked the documentation for fsolve, and it says it should indeed use a function handle there…

Answer 1

You miss the ‘@’ in front of nle, i.e.

 y = fsolve(@nle,x0);

should work.