Hong: in the latests versions of SLEPc we turn on this option by default 
(except in some solvers such as JD), so I don't think the problem is in the KSP 
solve.
Jose


> El 12 jul 2017, a las 19:53, Hong <[email protected]> escribió:
> 
> 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 <[email protected]> wrote:
> 
> > El 12 jul 2017, a las 18:56, Pandey, Siddhant <[email protected]> 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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