Getting NaN as my output when working with jacobi iteration

I believe it may be something with how I set up my matrices but I am not sure. Also I adapted some of the code from my textbook and I notice in the function they use abserr = norm(X'-P); and P = X';

What does ' do next to the X matrix I am trying to create? If I don't use this symbol I get an error for "matrix dimensions do not agree" when subtracting in the norm function.

Any help would be great.

My output looks like:

x =
   NaN   NaN   NaN

Script:

P = [0;0;0]; %initial guess
tol = 1e-10;
maxiter = 500;
A = [1 -5 -1; 4 1 -1; 2 -1 -6];
B = [-8; 13; -2];

x = jacobi(A,B,P,tol,maxiter)

Function File:

function [X,n] = jacobi(A, B, P, tol, maxiter)

N=length(B);

for n=1:maxiter
    for j = 1:N
        X(j) = (B(j)-A(j,[1:j-1,j+1:N])*P([1:j-1,j+1:N]))/A(j,j);
    end
    abserr = norm(X'-P);
    relerr = abserr/(norm(X) +eps);

      if (abserr <tol) && (relerr<tol)
          break;
      end
      P = X';
end

Answer 1

[Stephen23]

You should read the documentation for the transpose operator : "Matrix transpose. X' is the complex conjugate transpose of X. X.' is the nonconjugate transpose." This has been covered in plenty of other Answers .

Try it with a vector, and a simple matrix, and you will see the difference.

[Bo]

Thank you, but I am still confused as to why I am getting NaN as my output