[petsc-users] Condition number of matrix

[Florian Lindner]

Hello,

there is a FAQ and a Stackoverflow article about getting the condition number of a petsc matrix:

http://www.mcs.anl.gov/petsc/documentation/faq.html#conditionnumber
http://scicomp.stackexchange.com/questions/34/how-can-i-estimate-the-condition-number-of-a-large-sparse-matrix-using-petsc

Both tell me to add:

-pc_type none -ksp_type gmres -ksp_monitor_singular_value -ksp_gmres_restart 1000

to my options.

I add the line to .petscrc but nothing happens, no additional output at all. I added -ksp_view, so my .petscrc looks
like that:

-ksp_view
-pc_type none -ksp_type gmres -ksp_monitor_singular_value -ksp_gmres_restart 1000

The complete output is below, but something I wonder about:

GMRES: restart=30, shouldn't that be 1000

And where can I read out the condition number approximation?

Thanks,
Florian


KSP Object: 1 MPI processes
  type: gmres
    GMRES: restart=30, using Classical (unmodified) Gram-Schmidt Orthogonalization with no iterative refinement
    GMRES: happy breakdown tolerance 1e-30
  maximum iterations=10000
  tolerances:  relative=1e-09, absolute=1e-50, divergence=10000.
  left preconditioning
  using nonzero initial guess
  using PRECONDITIONED norm type for convergence test
PC Object: 1 MPI processes
  type: none
  linear system matrix = precond matrix:
  Mat Object:  C   1 MPI processes
    type: seqsbaij
    rows=14403, cols=14403
    total: nonzeros=1044787, allocated nonzeros=1123449
    total number of mallocs used during MatSetValues calls =72016
        block size is 1
(0) 13:58:35 [precice::impl::SolverInterfaceImpl]:395 in initialize: it 1 of 1 | dt# 1 | t 0 of 1 | dt 1 | max dt 1 |
ongoing yes | dt complete no |
(0) 13:58:35 [precice::impl::SolverInterfaceImpl]:446 in advance: Iteration #1
KSP Object: 1 MPI processes
  type: gmres
    GMRES: restart=30, using Classical (unmodified) Gram-Schmidt Orthogonalization with no iterative refinement
    GMRES: happy breakdown tolerance 1e-30
  maximum iterations=10000
  tolerances:  relative=1e-09, absolute=1e-50, divergence=10000.
  left preconditioning
  using nonzero initial guess
  using PRECONDITIONED norm type for convergence test
PC Object: 1 MPI processes
  type: none
  linear system matrix = precond matrix:
  Mat Object:  C   1 MPI processes
    type: seqsbaij
    rows=14403, cols=14403
    total: nonzeros=1044787, allocated nonzeros=1123449
    total number of mallocs used during MatSetValues calls =72016
        block size is 1