iteration     0 solution vector:
iteration     0 residual norm  0.1118E+01
iteration     1 solution vector:
iteration     1 residual norm  0.5916E+00
iteration     2 solution vector:
iteration     2 residual norm  0.3162E+00
iteration     3 solution vector:
iteration     3 residual norm  0.2570E-16
Norm of error < 1.e-12 iterations     3
