Loop Updating Vectors for Number of Iterations

Hello,

I am trying to create a loop that will update a vector for a given number of iterations but keep getting errors. The x0 vector is solved and I would like to set as the first iteration. I would appreciate any help :)

What I am Trying to Implement:

x0 = A\b
x1 = A\x0
x2 = A\x1
...
xn = A\x(n-1)

My Code:

clear, clc;
% Given Information
A = [3 2 3; 5 5 6; 9 8 9];
b = [1; 2; 3];
x0 = A\b; % Calculate x0 vector

% My Attempt at Loop
b_ = zeros(size(b)); % Initialize?
x_ = zeros(size(x0)); % Initialize?

for k = 1:200
    x(k(1)) = x_ + x0 % First Iteration
    b(k) = b_ + x(k) % Update b vector
    x(k+1) = A\b(k)  % Updated x vector
end

[Walter Roberson]

Is it correct that your b is always the previous x (except for the first time) ? Your use of those updates with 0 is confusing the issue if they are not needed.

[Denzel Philip Belleza]

Hi Walter,

Yes, I am trying to have b always updated to the previous x.

Answer 1

[Asad (Mehrzad) Khoddam]

Simply use

A = [3 2 3; 5 5 6; 9 8 9];
b = [1; 2; 3];
x=b;
for k=1:200
    x=A\x;
end