how to change variable value from another function

Hi, is there any way to change the value of a and b without change the function's signature. like global variable in c?

[Stephen23]

"is there any way to change the value of a and b without change the function's signature"

There may well be, but it would be buggy, quite horrible code. Ugh, global variables....

https://blogs.mathworks.com/videos/2010/03/08/top-10-matlab-code-practices-that-make-me-cry/

I think the more important question is why do you want to do this? What is your actual reason for specifying "...without change the function's signature"? Why can't you change the function, or use function parameterization? It seems to me that this question shows a very high probability of this problem:

http://xyproblem.info/

https://mywiki.wooledge.org/XyProblem

What is the real issue that you are having?

Answer 1

[Steven Lord]

If by "implementation of brent" you mean Brent's method, depending on how that's implemented you may be able to write your function that accepts a, b, and c as inputs and use one of the parameterizing techniques from this documentation page to fix a and b and let the Brent's method implementation call the parameterized function with values for c as Stephen suggested.

[yon am]

i will use it to change a and b.

Answer 2

[yon am]

i found this

    function [n] =try_b(t)
    global a
    global b   
    a=a*t;
    b=b*(1-t);

i can't change the signature because i am using implementation of brent and i should pass this function as a variable to brent function which gets a function with one argument.

[Stephen23]

@yon am: don't use global variables. Parameterizing the function is more efficient, and less buggy.

https://www.mathworks.com/help/matlab/math/parameterizing-functions.html

[yon am]

thanks a lot