[petsc-dev] SLEPc failure

Mon Oct 30 12:11:48 CDT 2017

I am getting a MUMPS error in numerical factorization...
Anyway, your B matrix is singular, with a high-dimensional nullspace. Maybe this is producing small negative values when computing v'*B*v.
There is no way to relax the check. You should solve the problem as non-symmetric. Or use Arpack if it works for you.

Jose

> El 30 oct 2017, a las 17:16, Franck Houssen <franck.houssen at inria.fr> escribió:
> 
> I deal with domain decomposition. It was faster/easier to generate files with 1 proc: I guess the "dirichlet" and "neumann" matrices are the same in this case, so one get the same files in the end... I didn't realized that when I sent the files. My mistake.
> 
> At my side, when I use krylovschur, SLEPc fails using 1, 2, 4, 8, ... procs (each proc performs a SLEPc solve that may fail or not - difficult to catch one). For instance, I attached data of one failed domain out of 8 (8 MPI procs): matrices are very close but different. Moreover, I added EPS logs of the same run and domain but replacing krylovschur with arpack when SLEPc does not fail (regarding your remark that B could be indefinite, I added -mat_mumps_icntl_33 1 to get the determinant). 
> 
> Anyway, I don't expect you spend too much time on this. My understanding is that there is no way to relax this check ? Correct ?
> 
> 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: Samedi 28 Octobre 2017 17:40:41
>> Objet: Re: [petsc-dev] SLEPc failure
>> 
>> The two matrices are the same ...
>> 
>>> El 28 oct 2017, a las 13:11, Franck Houssen <franck.houssen at inria.fr>
>>> escribió:
>>> 
>>> I just added that before EPSSetOperators:
>>> PetscViewer viewerA;
>>> PetscViewerBinaryOpen(PETSC_COMM_WORLD,"Atau.out",FILE_MODE_WRITE,&viewerA);
>>> MatView(A,viewerA);
>>> PetscViewer viewerB;
>>> PetscViewerBinaryOpen(PETSC_COMM_WORLD,"Btau.out",FILE_MODE_WRITE,&viewerB);
>>> MatView(B,viewerB);
>>> 
>>> At first, I avoided binary as I didn't know if the format handles
>>> big/little endianness... So I prefered ASCII.
>>> 
>>> Binary data are attached.
>>> 
>>> Franck
>>> 
>>> PS : running debian with little endian.
>>>>> python -c "import sys;print(0 if sys.byteorder=='big' else 1)"
>>> 1
>>> 
>>> 
>>> ----- 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 18:52:56
>>>> Objet: Re: [petsc-dev] SLEPc failure
>>>> 
>>>> I cannot load the files you sent. Please send the matrices in binary
>>>> format.
>>>> The easiest way is to run your program with -eps_view_mat0 binary:Atau.bin
>>>> -eps_view_mat1 binary:Btau.bin
>>>> 
>>>> However, the files are written at the end of EPSSolve() so if the solve
>>>> fails
>>>> then it will not create the files. You can try running with -eps_max_it 1
>>>> or add code in your main program to write the matrices.
>>>> 
>>>> Jose
>>>> 
>>>> 
>>>>> El 27 oct 2017, a las 12:28, Franck Houssen <franck.houssen at inria.fr>
>>>>> escribió:
>>>>> 
>>>>> 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
>>>>>>>> 
>>>>>>>> 
>>>>>> 
>>>>>> 
>>>>> <ABtau.tar.gz>
>>>> 
>>>> 
>>> <ABtau.tar.gz>
>> 
>> 
> <slepc.tar.gz>