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
