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<font size="2"><span style="font-size:11pt" class="elementToProof">Hi Jose,<br>
<br>
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.<br>
</span></font></div>
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<font size="2"><span style="font-size:11pt">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.
<br>
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<font size="2"><span style="font-size:11pt" class="elementToProof"> 14 EPS converged value (error) #0 -0.000164282 (5.36813206e-09)
<div> 16 EPS converged value (error) #1 -0.000160691+2.17113e-05i (3.37429620e-09)</div>
<div> 16 EPS converged value (error) #2 -0.000160691-2.17113e-05i (3.37429620e-09)</div>
<div> Solution method: krylovschur</div>
<div><br>
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<div> Number of requested eigenvalues: 2</div>
<div> Linear eigensolve converged (3 eigenpairs) due to CONVERGED_TOL; iterations 16</div>
<div> ---------------------- --------------------</div>
<div> k ||Ax-kx||/||kx||</div>
<div> ---------------------- --------------------</div>
<div> -0.000164 0.0613788</div>
<div> -0.000161+0.000022i 0.0773339</div>
<div> -0.000161-0.000022i 0.0774536</div>
<div> ---------------------- --------------------</div>
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<br>
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<font size="2"><span style="font-size:11pt">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?
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<br>
Best regards,<br>
Feng</span></font><br>
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<div id="divRplyFwdMsg" dir="ltr"><font style="font-size:11pt" face="Calibri, sans-serif" color="#000000"><b>From:</b> Jose E. Roman <jroman@dsic.upv.es><br>
<b>Sent:</b> 23 August 2022 5:24<br>
<b>To:</b> feng wang <snailsoar@hotmail.com><br>
<b>Cc:</b> petsc-users <petsc-users@mcs.anl.gov><br>
<b>Subject:</b> Re: [petsc-users] Slepc Question, shell-matrix</font>
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<div class="PlainText">Please always respond to the list, otherwise the thread appears as unresolved in the archives of the mailing list.<br>
<br>
<br>
> El 22 ago 2022, a las 22:45, feng wang <snailsoar@hotmail.com> escribió:<br>
> <br>
> Hi Jose,<br>
> <br>
> 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.
<br>
> <br>
> Many thanks for your help!<br>
> <br>
> Best regards,<br>
> Feng<br>
> From: Jose E. Roman <jroman@dsic.upv.es><br>
> Sent: 22 August 2022 19:32<br>
> To: feng wang <snailsoar@hotmail.com><br>
> Cc: petsc-users@mcs.anl.gov <petsc-users@mcs.anl.gov><br>
> Subject: Re: [petsc-users] Slepc Question, shell-matrix<br>
> <br>
> 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.<br>
> <br>
> Jose<br>
> <br>
> <br>
> > El 22 ago 2022, a las 20:45, feng wang <snailsoar@hotmail.com> escribió:<br>
> > <br>
> > Hello,<br>
> > <br>
> > 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.
<br>
> > <br>
> > My first attempt was not successful and I got the following errors:<br>
> > <br>
> > [0]PETSC ERROR: --------------------- Error Message --------------------------------------------------------------<br>
> > [0]PETSC ERROR: Missing or incorrect user input <br>
> > [0]PETSC ERROR: The inner product is not well defined: indefinite matrix<br>
> > [0]PETSC ERROR: See <a href="https://petsc.org/release/faq/" data-auth="NotApplicable">
https://petsc.org/release/faq/</a> for trouble shooting.<br>
> > [0]PETSC ERROR: Petsc Release Version 3.17.4, unknown <br>
> > [0]PETSC ERROR: cfdtest on a arch-debug named ming by feng Mon Aug 22 19:21:41 2022<br>
> > [0]PETSC ERROR: Configure options --with-cc=mpicc --with-cxx=mpicxx --with-fc=0 PETSC_ARCH=arch-debug<br>
> > [0]PETSC ERROR: #1 BV_SafeSqrt() at /home/feng/cfd/slepc-3.17.1/include/slepc/private/bvimpl.h:130<br>
> > [0]PETSC ERROR: #2 BV_SquareRoot_Default() at /home/feng/cfd/slepc-3.17.1/include/slepc/private/bvimpl.h:365<br>
> > [0]PETSC ERROR: #3 BVOrthogonalizeCGS1() at /home/feng/cfd/slepc-3.17.1/src/sys/classes/bv/interface/bvorthog.c:101<br>
> > [0]PETSC ERROR: #4 BVOrthogonalizeGS() at /home/feng/cfd/slepc-3.17.1/src/sys/classes/bv/interface/bvorthog.c:177<br>
> > [0]PETSC ERROR: #5 BVOrthonormalizeColumn() at /home/feng/cfd/slepc-3.17.1/src/sys/classes/bv/interface/bvorthog.c:402<br>
> > [0]PETSC ERROR: #6 BVMatArnoldi() at /home/feng/cfd/slepc-3.17.1/src/sys/classes/bv/interface/bvkrylov.c:91<br>
> > [0]PETSC ERROR: #7 EPSSolve_KrylovSchur_Default() at /home/feng/cfd/slepc-3.17.1/src/eps/impls/krylov/krylovschur/krylovschur.c:261<br>
> > [0]PETSC ERROR: #8 EPSSolve() at /home/feng/cfd/slepc-3.17.1/src/eps/interface/epssolve.c:147<br>
> > [0]PETSC ERROR: #9 slepc_eigen_comp() at domain/cfd/slepc_eigen_solve.cpp:77<br>
> > <br>
> > 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.<br>
> > <br>
> > Many thanks,<br>
> > Feng<br>
> > <slepc_eigen_solve.cpp><br>
<br>
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