Call a function with inputs from different sources

I am trying to input an anonymous function into a full function so that the full function can evaluate the anonymous function. The problem seems to be that the anonymous function is in a loop along with the full function and two of the variables in the anonymous function are meant to update at every interation but it doesn't seem to update.

    for i = 1:5
    d = -df(x)
    %x = x+a*d;
    ff = @(x, d) ((x(1)+a*d(1)) + 4*(x(2)+a*d(2)) - 3)^2 +...
        (2*(x(1)+a*d(1)) + 5*(x(2)+a*d(2)) - 15)^2;
    fff = @(a) ff(x, d);
    if norm(d) == 0 || abs(norm(d)) < 0.1
        break
    end
    alpha = Golden_section(fff, 0)
    x = x +(alpha*d)
end

just wondering if there's any way for me to do this. As you can see above, I tried inputting the first two variables before calling the function in the golden section function but it just says that a does not exists.

Answer 1

[Andrei Bobrov]

try is it:

ff = @(x, d,a) ((x(1)+a*d(1)) + 4*(x(2)+a*d(2)) - 3)^2 +...
        (2*(x(1)+a*d(1)) + 5*(x(2)+a*d(2)) - 15)^2;
x = ...; % input initial x
for i = 1:5
    d = -df(x);
    if norm(d) == 0 || abs(norm(d)) < 0.1
        break
    end
    alpha = Golden_section(@(a)ff(x,d,a), 0);
    x = x +(alpha*d);
end

[Samuel Mustapha]

Thank you so much. Worked.