[petsc-users] SLEPC solvers not converging in latest version

[Hong]

Add option '-ksp_error_if_not_converged'.  I suspect the matrix has zero
pivot.
Hong

On Wed, Jul 12, 2017 at 12:45 PM, Jose E. Roman <jroman at dsic.upv.es> wrote:

>
> > El 12 jul 2017, a las 18:56, Pandey, Siddhant <spandey2 at wpi.edu>
> escribió:
> >
> > We recently updated our installation of PETSC and SLEPC from an older
> version, and eigenvalue problems converging in the previous installation is
> not converging anymore (diagonalization never comes to an end). On using
> -info, the following message keeps repeating during diagonalization:
> >
> > [0] PCSetUp(): Leaving PC with identical preconditioner since operator
> is unchanged
> > [0] STMatSolve(): Linear solve iterations=1
> > [0] PCSetUp(): Leaving PC with identical preconditioner since operator
> is unchanged
> > [0] STMatSolve(): Linear solve iterations=1
> > [0] BV_SafeSqrt(): Zero norm, either the vector is zero or a semi-inner
> product is being used
> > [0] PCSetUp(): Leaving PC with identical preconditioner since operator
> is unchanged
> > [0] STMatSolve(): Linear solve iterations=1
> > [0] PCSetUp(): Leaving PC with identical preconditioner since operator
> is unchanged
> > [0] STMatSolve(): Linear solve iterations=1
> >
> > As can be seen, iteration number remains 1. The issue gets resolved with
> a smaller sized matrix. Currently I am using a 10648 x 10648 matrix, and
> PETSC is configured for complex values.
> >
> > What changes do I have to make to make my codes work in the new
> installation? This seems to be a version specific issue.
> >
> >
> > Thanks,
> > Sidd
> > WPI
>
> I don't understand why are you getting the BV message. Maybe your B-matrix
> is singular, but it is not sufficient to explain this. If possible, send me
> your matrices and I will try to reproduce the problem (I would also need to
> know all the settings, which can be displayed with -eps_view or
> -eps_view_pre).
>
> Jose
>
>
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