[petsc-users] help on ksp

[Barry Smith]

   Incorrect preallocation should never cause a crash (just possibly slower code). You need to run valgrind http://www.mcs.anl.gov/petsc/petsc-as/documentation/faq.html#valgrind

  Barry

On Apr 6, 2011, at 6:53 PM, NAN ZHAO wrote:

> Dear all, 
> 
> I tried to use ksp to solve some problem. I got some Segmentation Violation error. And I got result from the solver as below. I am wondering if the ksp matrix has some error, cause I got the nonzeros allocated wrong. Can anyone dig out some valuable information from the ksp output? Thanks.
> --------------------------------------------------------------------------------------------------
>   total: nonzeros=38449, allocated nonzeros=52103
> reason code = 2, its = 2546
> KSP Object:
>   type: gmres
>     GMRES: restart=30, using Classical (unmodified) Gram-Schmidt Orthogonalization with no iterative refinement
>     GMRES: happy breakdown tolerance 1e-30
>   maximum iterations=5000, initial guess is zero
>   tolerances:  relative=1e-05, absolute=1e-50, divergence=10000
>   left preconditioning
> PC Object:
>   type: ilu
>     ILU: 0 levels of fill
>     ILU: factor fill ratio allocated 1
>     ILU: tolerance for zero pivot 1e-12
>          out-of-place factorization
>          matrix ordering: natural
>     ILU: factor fill ratio needed 0
>          Factored matrix follows
>         Matrix Object:
>           type=seqbaij, rows=2903, cols=2903
>           total: nonzeros=38449, allocated nonzeros=52103
>               block size is 1
>  linear system matrix = precond matrix:
>   Matrix Object:
>     type=seqbaij, rows=2903, cols=2903
>     total: nonzeros=38449, allocated nonzeros=52103
>         block size is 1
> 
> Nan