[petsc-users] Zeroed solution after 0 iterations

[John Mousel]

I have a colleague who is trying to run some simple test cases. He noticed
if he provides the solution vector as the exact solution with a non-zero
guess tagged, that the solution vector is zeroed upon return after 0
iterations. The system is just a 5x5 matrix corresponding to a heat
equation with Dirichlet BCs. I've copied the KSPView below. He's using
petsc-3.6.3.

John

solution before kspsolve:Vec Object: 1 MPI processes
  type: mpi
Process [0]
300
300
300
300
300
KSP Object: 1 MPI processes
  type: bcgs
  maximum iterations=100
  tolerances:  relative=1e-15, absolute=1e-50, divergence=10000
  right preconditioning
  using nonzero initial guess
  using UNPRECONDITIONED norm type for convergence test
PC Object: 1 MPI processes
  type: ilu
    ILU: out-of-place factorization
    0 levels of fill
    tolerance for zero pivot 2.22045e-14
    matrix ordering: natural
    factor fill ratio given 1, needed 1
      Factored matrix follows:
        Mat Object:         1 MPI processes
          type: seqaij
          rows=5, cols=5
          package used to perform factorization: petsc
          total: nonzeros=25, allocated nonzeros=25
          total number of mallocs used during MatSetValues calls =0
            using I-node routines: found 1 nodes, limit used is 5
  linear system matrix = precond matrix:
  Mat Object:   1 MPI processes
    type: seqaij
    rows=5, cols=5
    total: nonzeros=25, allocated nonzeros=25
    total number of mallocs used during MatSetValues calls =0
      using I-node routines: found 1 nodes, limit used is 5
solution after kspsolve:Vec Object: 1 MPI processes
  type: mpi
Process [0]
0
0
0
0
0
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