Question: How to find tolerance?

> restart;
> with(LinearAlgebra);
> tolerance = 10^(-3); x1km1 := 0; x2km1 := 0; x3km1 := 0; for k to 2 do k := k; x1k := 1/4*(5-x2km1+x3km1); x2k := 1/3*(-4+x1km1-x3km1); x3k := 1/5*(1-2*x1km1-2*x2km1); evalf(x1k); evalf(x2k); evalf(x3k) end do;
                               1
                               5
                               -
                               4
                               -4
                               --
                               3 
                               1
                               -
                               5
                          1.250000000
                          -1.333333333
                          0.2000000000
                               2
                               5
                               -
                               4
                               -4
                               --
                               3 
                               1
                               -
                               5
                          1.250000000
                          -1.333333333
                          0.2000000000