为什么这个MatLab Gauss-Seidel迭代求解器陷入循环？

Question

我花了最后五个小时试图理解为什么这段代码陷入了无限循环。我发誓，我按照我在网上和其他地方的说明完全按照。感觉就像我尝试的一切都不起作用，我不知道为什么。

function [ K ] = linearSolve( a, b )
%Solves a system of equations. a = matrix of equations ; b = matrix
%of solutions

clear all
clc


%Example Matrices

a = [2,1,3;-2,-3,1;-3,4,-1];
b = [1,0,3];


%Defining initial & user values...

allowedError = input('Enter your max allowed error before stopping, in %: ');
X = input('Enter your inital guess matrix X: ');
dims = size(a);
iterations = 1;
maxiter = input('Maximum iterations: ');
error = allowedError + 100;


%Setting up K[i,j] matrix:

for r = 1:dims(1)

    for c = 1:dims(2)
        K(r,c) = -1*a(r,c)/a(r,r);

        if r == c
            K(r,c) = 0;
        end
    end

    d(r) = b(r) / a(r,r);
end


%Performing Iteration...

while error > allowedError

    iterations = iterations + 1;

    prevGuess = X;
    for j = 1:dims(1)

        X(j) = K(j,:)*X(:) + d(j);
        error(j) = abs(((X(j) - prevGuess(j))/X(j))*100);
    end

    if (allowedError >= error) | (iterations >= maxiter)
        break
    end
end


%Display Results
disp('The values of X are: ');
disp(X);
disp('------------------------------------');
disp('The error is: ');
disp(error);

end