[petsc-dev] SLEPc failure

[Franck Houssen]

Maybe could be convenient for the users to have an option (or an EPSSetXXX) to relax that check ?
Data are attached.

Franck 

----- Mail original -----
> De: "Jose E. Roman" <jroman at dsic.upv.es>
> À: "Franck Houssen" <franck.houssen at inria.fr>
> Cc: "For users of the development version of PETSc" <petsc-dev at mcs.anl.gov>
> Envoyé: Vendredi 27 Octobre 2017 10:15:44
> Objet: Re: [petsc-dev] SLEPc failure
> 
> There is no new option. What I mean is that from 3.7 to 3.8 we changed the
> line that produces this error. But it seems that it is still failing in your
> problem. Maybe your B matrix is indefinite or not exactly symmetric. Can you
> send me the matrices?
> Jose
> 
> > El 27 oct 2017, a las 9:57, Franck Houssen <franck.houssen at inria.fr>
> > escribió:
> > 
> > I use the development version (bitbucket clone). How to relax the check ?
> > At command line option ?
> > 
> > Franck
> > 
> > ----- Mail original -----
> >> De: "Jose E. Roman" <jroman at dsic.upv.es>
> >> À: "Franck Houssen" <franck.houssen at inria.fr>
> >> Cc: "For users of the development version of PETSc"
> >> <petsc-dev at mcs.anl.gov>
> >> Envoyé: Jeudi 26 Octobre 2017 18:49:22
> >> Objet: Re: [petsc-dev] SLEPc failure
> >> 
> >> 
> >>> El 26 oct 2017, a las 18:36, Franck Houssen <franck.houssen at inria.fr>
> >>> escribió:
> >>> 
> >>> Here is a stack I end up with when trying to solve an eigen problem
> >>> (real,
> >>> sym, generalized) with SLEPc. My understanding is that, during the Gram
> >>> Schmidt orthogonalisation, the projection of one basis vector turns out
> >>> to
> >>> be null.
> >>> First, is this correct ? Second, in such cases, are there some
> >>> recommended
> >>> "recipe" to test/try (options) to get a clue on the problem ? (I would
> >>> unfortunately perfectly understand the answer could be no !... As this
> >>> totally depends on A/B).
> >>> 
> >>> With arpack, the eigen problem is solved (so the matrix A and B I use
> >>> seems
> >>> to be relevant). But, when I change from arpack to
> >>> krylovschur/ciss/arnoldi, I get the stack below.
> >>> 
> >>> Franck
> >>> 
> >>> [0]PETSC ERROR: #1 BV_SafeSqrt()
> >>> [0]PETSC ERROR: #2 BVNorm_Private()
> >>> [0]PETSC ERROR: #3 BVNormColumn()
> >>> [0]PETSC ERROR: #4 BV_NormVecOrColumn()
> >>> [0]PETSC ERROR: #5 BVOrthogonalizeCGS1()
> >>> [0]PETSC ERROR: #6 BVOrthogonalizeGS()
> >>> [0]PETSC ERROR: #7 BVOrthonormalizeColumn()
> >>> [0]PETSC ERROR: #8 EPSFullLanczos()
> >>> [0]PETSC ERROR: #9 EPSSolve_KrylovSchur_Symm()
> >>> [0]PETSC ERROR: #10 EPSSolve()
> >> 
> >> Is this with SLEPc 3.8? In SLEPc 3.8 we relaxed this check so I would
> >> suggest
> >> trying with it.
> >> Jose
> >> 
> >> 
> 
> 
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