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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 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 <[email protected]> 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 <[email protected]> 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 <[email protected]> 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
