John,
We'll need the full code to debug this. It doesn't see this should happen.
Barry
> On Apr 13, 2016, at 7:11 AM, John Mousel <john.mousel at gmail.com> wrote:
>
> 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