If else condition for each iteration in "FSOLVE"

I want to implement a 'if statement' in every iteration of fsolve. In bellow code, b is a function x,y, and b comes from if else statement. How should I imlement it?

syms x y
a=atan2(x,y)
% condition to be implemented
if a<=0
    b=x+y;
else
    b=x-y;
end
fun =@(x,y) x^2 + y^2 + b; %function
x0=[0,0]; % [x,y]
out = fsolve(fun,x0)

Thanks in advance.

Answer 1

[Matt J]

That would create discontinuity in the function. fsolve is designed to solve problems with smooth, differentiable equation functions. You could, of course, invoke fsolve twice, once for b=1 and once for b=2. You could then check which solution satisfies the requirement on atan2(x,y).