Need Help with Newton's Method for the Following code; keep getting errors

clc; 
close all; 
clear all;

x = 1;
y = 2;

for i = 1:10   
    f(x) = (-x(i).^2) - (2*y(i)) + 2;
    f(y) = (-x(i)) - (4*y(i).^2) + 4;
    A(1,1) = 2*x(i);
    A(1,2) = 2;
    A(2,1) = 1;
    A(2,2) = 8*y(i);
    Z_new = f'\A + f; %f' denotes a column
    x(i) = Z_new(1,1);
    y(i) = Z_new(1,2);
end

end

[KSSV]

what is that code? It will not work. x and y are scalars, you are expecting it to be vector inside the loop. You have to read basics of matlab and the problem you are solving.

Answer 1

[Marc]

You may want to look into the following in the documentation:

• @ or annonymous functions
• preallocation

Cleve Moler's recent blog on Newton's method gives a good example of setting up an anonymous function, its derivative and has a simple implementation of newton's method already there.

http://blogs.mathworks.com/cleve/2016/01/18/fractal-global-behavior-of-newtons-method/