[petsc-users] Inertia computation fails

[Perceval Desforges]

Hello again, 

I've tried following your recommendations, and yet the computation still
fails with the same error message even when i take a very large interval
(the failed value is at 1.91 and the interval goes from 1.5 to 3). 

Could anything else be causing this? 

Thanks again. 

Best regards, 

Perceval, 

> Sorry I hadn't seen that you had responded. Thanks a lot, I'll try that. 
> 
> Regards, 
> 
> Perceval, 
> Are you using the EPSKrylovSchurSetDetectZeros() option? As in this example https://slepc.upv.es/documentation/current/src/eps/examples/tutorials/ex25.c.html
> If so, then the explanation is probably that one of the endpoints of your interval coincides with an eigenvalue. Try with a slightly different interval.
> 
> Jose
> 
> El 5 mar 2020, a las 14:51, Satish Balay via petsc-users <petsc-users at mcs.anl.gov> escribió:
> 
> The address here should be petsc-users - not petsc-users-bounces
> 
> balay at sb /home/balay/git-repo/slepc (master=)
> $ git grep 'Inertia computation fails'
> src/eps/impls/krylov/krylovschur/ks-slice.c:          if (zeros) SETERRQ1(((PetscObject)eps)->comm,PETSC_ERR_CONV_FAILED,"Inertia computation fails in %g",sr->int1);
> src/eps/impls/krylov/krylovschur/ks-slice.c:      if (zeros) SETERRQ1(((PetscObject)eps)->comm,PETSC_ERR_CONV_FAILED,"Inertia computation fails in %g",newShift);
> src/pep/impls/krylov/stoar/qslice.c:        if (!nconv) SETERRQ1(((PetscObject)pep)->comm,PETSC_ERR_CONV_FAILED,"Inertia computation fails in %g",nzshift);
> src/pep/impls/krylov/stoar/qslice.c:      if (zeros) SETERRQ1(((PetscObject)pep)->comm,PETSC_ERR_CONV_FAILED,"Inertia computation fails in %g",newShift);
> 
> So the message is likely coming from slepc
> 
> Satish
> 
> ---------- Forwarded message ----------
> Date: Thu, 05 Mar 2020 14:43:13 +0100
> From: Perceval Desforges <perceval.desforges at polytechnique.edu>
> To: petsc-users <petsc-users-bounces at mcs.anl.gov>
> Subject: Inertia computation fails
> 
> Dear PETSc developpers, I am using SLEPC and MUMPS to calculate the eigenvalues of a real
> symmetric matrix in an interval. I have come upon a crash and I was
> unable to find any documentation on the error I got. The error is:  Inertia computation fails in 2.19893 Is this a slepc, a Petsc or a mumps problem? Thanks, Perceval
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