Hi Jose,
I think the previous problem comes from my side. I have some uninitialized
values in my part of code to compute the non-linear residuals. so, it produces
a NAN when it tries to compute the matrix-vector product using finite
difference. This might make the slepc/pestc do unexpected things.
Now It seems I've got slepc running. eps_nev is set to 3 and I am trying to
compute the ones with the largest amplitudes. Below is the slepc output.
14 EPS converged value (error) #0 -0.000164282 (5.36813206e-09)
16 EPS converged value (error) #1 -0.000160691+2.17113e-05i (3.37429620e-09)
16 EPS converged value (error) #2 -0.000160691-2.17113e-05i (3.37429620e-09)
Solution method: krylovschur
Number of requested eigenvalues: 2
Linear eigensolve converged (3 eigenpairs) due to CONVERGED_TOL; iterations 16
---------------------- --------------------
k ||Ax-kx||/||kx||
---------------------- --------------------
-0.000164 0.0613788
-0.000161+0.000022i 0.0773339
-0.000161-0.000022i 0.0774536
---------------------- --------------------
The values in the brackets are the absolute error (I believe) and they seem
very low. The relative error seems quite large. Could you please comment on
this?
Best regards,
Feng
________________________________
From: Jose E. Roman <jro...@dsic.upv.es>
Sent: 23 August 2022 5:24
To: feng wang <snails...@hotmail.com>
Cc: petsc-users <petsc-users@mcs.anl.gov>
Subject: Re: [petsc-users] Slepc Question, shell-matrix
Please always respond to the list, otherwise the thread appears as unresolved
in the archives of the mailing list.
> El 22 ago 2022, a las 22:45, feng wang <snails...@hotmail.com> escribió:
>
> Hi Jose,
>
> I think I might have solved my problem. I have some uninitialized values in
> my part of code to compute the right hand side. so it produces a NAN when it
> tries to compute the matrix-vector product.
>
> Many thanks for your help!
>
> Best regards,
> Feng
> From: Jose E. Roman <jro...@dsic.upv.es>
> Sent: 22 August 2022 19:32
> To: feng wang <snails...@hotmail.com>
> Cc: petsc-users@mcs.anl.gov <petsc-users@mcs.anl.gov>
> Subject: Re: [petsc-users] Slepc Question, shell-matrix
>
> This is very strange. This error appears when the solver employs the B-inner
> product, but in your case you don't have a B matrix, so you should never see
> that error. Try running under valgrind to see if it gives more hints.
>
> Jose
>
>
> > El 22 ago 2022, a las 20:45, feng wang <snails...@hotmail.com> escribió:
> >
> > Hello,
> >
> > I am new to Slepc and trying to work out the eigenvalues and eigenvectors
> > of my Jacobian matrix. I am using a shell matrix to work out the
> > matrix-vector product and I am using the default Krylov-schur method.
> >
> > My first attempt was not successful and I got the following errors:
> >
> > [0]PETSC ERROR: --------------------- Error Message
> > --------------------------------------------------------------
> > [0]PETSC ERROR: Missing or incorrect user input
> > [0]PETSC ERROR: The inner product is not well defined: indefinite matrix
> > [0]PETSC ERROR: See https://petsc.org/release/faq/ for trouble shooting.
> > [0]PETSC ERROR: Petsc Release Version 3.17.4, unknown
> > [0]PETSC ERROR: cfdtest on a arch-debug named ming by feng Mon Aug 22
> > 19:21:41 2022
> > [0]PETSC ERROR: Configure options --with-cc=mpicc --with-cxx=mpicxx
> > --with-fc=0 PETSC_ARCH=arch-debug
> > [0]PETSC ERROR: #1 BV_SafeSqrt() at
> > /home/feng/cfd/slepc-3.17.1/include/slepc/private/bvimpl.h:130
> > [0]PETSC ERROR: #2 BV_SquareRoot_Default() at
> > /home/feng/cfd/slepc-3.17.1/include/slepc/private/bvimpl.h:365
> > [0]PETSC ERROR: #3 BVOrthogonalizeCGS1() at
> > /home/feng/cfd/slepc-3.17.1/src/sys/classes/bv/interface/bvorthog.c:101
> > [0]PETSC ERROR: #4 BVOrthogonalizeGS() at
> > /home/feng/cfd/slepc-3.17.1/src/sys/classes/bv/interface/bvorthog.c:177
> > [0]PETSC ERROR: #5 BVOrthonormalizeColumn() at
> > /home/feng/cfd/slepc-3.17.1/src/sys/classes/bv/interface/bvorthog.c:402
> > [0]PETSC ERROR: #6 BVMatArnoldi() at
> > /home/feng/cfd/slepc-3.17.1/src/sys/classes/bv/interface/bvkrylov.c:91
> > [0]PETSC ERROR: #7 EPSSolve_KrylovSchur_Default() at
> > /home/feng/cfd/slepc-3.17.1/src/eps/impls/krylov/krylovschur/krylovschur.c:261
> > [0]PETSC ERROR: #8 EPSSolve() at
> > /home/feng/cfd/slepc-3.17.1/src/eps/interface/epssolve.c:147
> > [0]PETSC ERROR: #9 slepc_eigen_comp() at domain/cfd/slepc_eigen_solve.cpp:77
> >
> > Could someone please shine some light on this? I have also attached my
> > code. The code is part of my big library and I cannot attach the whole
> > code, sorry about this. but I am happy to provide more information. The
> > attached code has some arrangements for halo exchange, but for the moment,
> > it assumes it is a serial run.
> >
> > Many thanks,
> > Feng
> > <slepc_eigen_solve.cpp>
