Initial guess
Vec Object:potential 1 MPI processes
  type: seq
0.5
L_2 Error: 0.111111
Initial Residual
Vec Object: 1 MPI processes
  type: seq
0.
L_2 Residual: 0.
Au - b = Au + F(0)
Vec Object: 1 MPI processes
  type: seq
0.
Linear L_2 Residual: 0.