Let me correct my last message: we set this option in the development version 
(master), so yes, in 3.7 it may be good to try -ksp_error_if_not_converged
Sorry for the noise.
Jose


> El 12 jul 2017, a las 19:58, Jose E. Roman <[email protected]> escribió:
> 
> 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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