Change a variable in a function.

Im using the fsolve function inside a loop and there is an integer inside the fsolve function that will change the solution of the fsolve, i want to increment that number each time the loop is conducted, i defined the term in global and gave it a value of 1 intially, then i tried using A=A+1 inside the loop but the fsolve gave me the final answer only to that equation and i tried putting the A=A+1 inside the function but it gave me an error.

Answer 1

[Nicolas B.]

I never tried with global variables but, in your case, I would recommend you to set your A has an input. What I understand, all variables which are not inputs of the function_handle are set as constant in the function_handle when you define it (but I could be wrong). So I would recommand to define your function handle as:

A = 1;
f = @(in1, in2, A) you_function(in1, in2, A);

while your_condition
    f(in1, in2, A);
    A = A + 1;
end

[Anas Albizreh]

Its telling me Undefined function or variable 'A'.

[Nicolas B.]

Can you add here your code please?

[Anas Albizreh]

I called it C here.

[Rik]

This time I edited your comment for you. Next time, please use the tools explained on this page to make your code more readable.

[Anas Albizreh]

Sorry im new here.

[Anas Albizreh]

Help me please.

[Nicolas B.]

You should add A to the input of func() and myfunc().

If I could give you a general advice, try to avoid as much as possible the global variables. It makes your script impossible to re-use and difficult to debug.

[Anas Albizreh]

Can you tell me how to do it, i tried doing it but it didn't work.

[Nicolas B.]

I don't have the optimization toolbox, so I cannot test it, but it should work like that (only the necessary code is shown:

global U Lg L2 L3 L4 L1 Th1 Th2 
...
x0 = [deg2rad(145), deg2rad(20)];
x = fsolve(@(x) myfunc(x, A),x0);

...
    
function F = myfunc(X, A)
    global U Lg
    thA = X(1);
    th2 = X(2);
    F(1) = real( U*exp(1i*th2)-A*exp(1i*thA)-Lg );
    F(2) = imag( U*exp(1i*th2)-A*exp(1i*thA)-Lg );
end