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You are calling EPSErrorView() somehow. This function checks the residual errors. If you requested EPS_ERROR_RELATIVE then the error for the zero eigenvalues will be large (division by 0). Are you calling EPSErrorView() three times? Probably
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<meta charset="utf-8"></head><body><pre style="font-family: sans-serif; font-size: 100%; white-space: pre-wrap; word-wrap: break-word">You are calling EPSErrorView() somehow. This function checks the residual errors. If you requested EPS_ERROR_RELATIVE then the error for the zero eigenvalues will be large (division by 0).
Are you calling EPSErrorView() three times? Probably the 3rd message is a call with EPS_ERROR_ABSOLUTE, in which case all errors are below the tolerance.
Jose
> El 7 mar 2024, a las 16:29, Eric Chamberland <Eric.Chamberland@giref.ulaval.ca> escribió:
>
> Hi,
> wow, it was only that, it's now working perfectly!
> Curiously, I still have 2 times the message about relative errors followed by a new one with converged values, see:
> options_eps_gen Linear eigensolve converged (13 eigenpairs) due to CONVERGED_TOL; iterations 2
> Problem: some of the first 10 relative errors are higher than the tolerance
>
> Problem: some of the first 10 relative errors are higher than the tolerance
>
> All requested eigenvalues computed up to the required tolerance:
> 0.00000, 0.00000, 0.00000, 199.28609, 415.65289, 570.21994, 1294.72406, 1295.67360,
> 3769.78800, 3771.15894
>
>
> So is it intended to write these 2 warnings?
> Anyway thanks a lot! :)
> Eric
>
> On 2024-03-07 02:24, Jose E. Roman wrote:
>> Pierre's diagnostic is right, but the suggested option is wrong: it should be -eps_target
>> Also, I would suggest using a larger value, such as -eps_target 0.1, otherwise the tolerance 1e-14 might not be attained.
>>
>> Jose
>>
>>
>>
>>> El 7 mar 2024, a las 8:01, Pierre Jolivet <pierre@joliv.et> escribió:
>>>
>>> This Message Is From an External Sender
>>> This message came from outside your organization.
>>> It seems your A is rank-deficient.
>>> If you slightly regularize the GEVP, e.g., -st_target 1.0E-6, you’ll get errors closer to 0.
>>>
>>> Thanks,
>>> Pierre
>>>
>>>
>>>> On 6 Mar 2024, at 8:57 PM, Eric Chamberland via petsc-users <petsc-users@mcs.anl.gov> wrote:
>>>>
>>>> This Message Is From an External Sender
>>>> This message came from outside your organization.
>>>> Hi,
>>>>
>>>> we have a simple generalized Hermitian problem (Kirchhoff plate
>>>> vibration) for which we are comparing SLEPc results with Matlab results.
>>>>
>>>> SLEPc computes eigenvalues correctly, as Matlab does.
>>>>
>>>> However, the output eigenvectors are not fully converged and we are
>>>> trying to understand where we have missed a convergence parameter or
>>>> anything else about eigenvectors.
>>>>
>>>> SLEPc warns us at the end of EPSSolve with this message:
>>>>
>>>> ---
>>>> Problem: some of the first 10 relative errors are higher than the
>>>> tolerance
>>>> ---
>>>>
>>>> And in fact, when we import the resulting vectors into Matlab,
>>>> "A*x-B*Lambda*x" isn't close to 0.
>>>>
>>>> Here are attached the EPS view output as the A and B matrices used.
>>>>
>>>> Any help or insights will be appreciated! :)
>>>>
>>>> Thanks,
>>>> Eric
>>>>
>>>> <epsview.txt><matrice0_gen.m><matrice1_gen.m>
>>>>
> --
> Eric Chamberland, ing., M. Ing
> Professionnel de recherche
> GIREF/Université Laval
> (418) 656-2131 poste 41 22 42
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