Creating loop that produces variable values that meet convergence conditions with matrices.

I am trying to create a loop that will take the equation of A*x(i)=(1/k(i-1))*B*x(i-1) and solve for the x(i). Then produces the x(i) and k(i) that meet the conditions abs(k(i)-k(i-1))/k(i)<=error && abs(x(i)-x(i-1))/x(i)<=error.

k(i)=k(i-1)*(x(i) / x(i-1))

A=6x6 matrix of diagonal values along the main diag and the upper/lower diag around the

main diag

B=6x6 matrix of diagonal values along the main diag

The initial x(i-1=0) is equal to a 6x1 vector of 1's.

The initial k(i-1=0) is equal to a scalar of 1.

error=designated value of the error convergence criterion.

I know of using a for loop and if function but do not know just how to place it.