How to get the jacobian of a array function and evaluate it??...

Hi!, hoping someone could help me, i've trying to write a code for Newton-Rhapson method for nonlinear systems, so, I've declarated a Symbolic function

F= @(x) [x(1).^2+x(2).^2-1,x(1).^2-x(2).^2]

I need to find the jacobian for that array of functions, but jacobian(f,v) only acepts symbolic functions with x and y, but i can't convert the last expresion to a symbolic function with 'x' and 'y' because I need to use 'feval()' later

After that, I need to use 'feval()' in jacobian matrix

Someone could help me please?

Answer 1

[David Hill]

This might help:

https://www.mathworks.com/help/symbolic/jacobian.html?s_tid=srchtitle

[Alejandro Noriega Soto]

Excuse me, submit before typing the entire problem...

[David Hill]

F= [x^2+y^2-1,x^2-y^2];
j=jacobian(F,[x,y]);
x=5;y=3;
subs(j);%use subs instead of feval

[Alejandro Noriega Soto]

And if i want to use an array to evaluate it?...

[David Hill]

Use for-loop

evalArray=[1,2;3,4;5,6];
for k=1:size(evalArray,1)
    x=evalArray(k,1);
    y=evalArray(k,2);
    Jeval(k)=subs(j);
end