Thanks, Bruno and Jean-Paul. I will not use the TrilinosWrapper::SolverDirect in inverse_operator, replaced by an iterative solver. But Bruno, this example initializes a precondition by a matrix
preconditioner.initialize(system_matrix, data); While I can't get the entity of the matrix, I want to get the precondition directly from a linear_operator. SparseMatrix M; auto op_M = linear_operator(M); TrilinosWrapper::PreconditionILU prec_M(op_M); Or in other hands, Can I get the entity of a matrix from the linear_operator? For example: SparseMatrix A, B, C, D, E, F; linear_operator op_A, op_B, op_C, op_D, op_E, op_F; inverse_operator inv_C(op_C, solver, prec_C), inv_E(op_E, solver, prec_E); linear_operator op_G=op_A-op_B*inv_C*op_D-inv_E*op_F; Can I get the entity of matrix G by TrilinosWrapper::MPI::SparseMatrix G = op_G; or the precondition of op_G? auto prec_G = linear_operator(op_G, TrilinosWrapper::PreconditionILU); seems don't wok. Best, Chen 在2022年4月20日星期三 UTC+8 00:19:46<Jean-Paul Pelteret> 写道： > Dear Chen, > > Bruno pointed you to the exact example that I was going to. It is > certainly possible to use linear operators as preconditioners for solvers. > > It looks like support for TrilinosWrappers::SolverDirect has not yet been > implemented: > > https://github.com/dealii/dealii/blob/master/tests/lac/linear_operator_10.cc#L371-L414 > I cannot recall what the reason was — maybe the class is simply missing > some functions that are defined for the iterative solvers? > > As for one of your early questions which Bruno did already answer: I must > admit that I do not know if the PETSc linear algebra is compatible with > linear operators. We had to write a special TrilinosPayload > <https://dealii.org/current/doxygen/deal.II/classTrilinosWrappers_1_1internal_1_1LinearOperatorImplementation_1_1TrilinosPayload.html> > for > the Trilinos linear algebra classes in order for them to work correctly > (with the Trilinos solvers, at least), and such a wrapper doesn’t exist for > PETSc. But maybe it works just fine if you stick to the deal.II solvers? If > you try this out, it would be interesting to know if it works or not. > > Best, > J-P > > On 19. Apr 2022, at 17:27, Bruno Turcksin <[email protected]> wrote: > > Chen, > > I am not sure if TrilinosWrappers::SolverDirect is supported but for your > second point, you can use the linear_operator as a preconditioner. That's > exactly what's done here > <https://github.com/dealii/dealii/blob/master/tests/lac/step-40-linear_operator_06.cc#L220-L251> > for example. The preconditioner is wrapped in a LinearOperator and this > LinearOperator is then used as preconditioner. > > Best, > > Bruno > > On Tuesday, April 19, 2022 at 10:39:17 AM UTC-4 [email protected] wrote: > >> Hi everyone, >> >> More questions: >> 1. where can I find the supported linear solver of Trilinos of >> linear_operator? TrilinosWrappers::SolverDirect seems not to be supported >> by the linear_operator >> 2. Does linear_operator can be a preconditioner? for example, SparseMatrix >> A, B, C, D, E, F; Matrix G=A-B*C^{-1}*D-E^{-1}*F; So Matrix G can only >> represent by a linear_operator, not its entity. I want to get its inverse >> by inverse_operator using some linear solvers as: PreconditionILU >> prec_G(op_G); const auto op_G_inv = inverse_operator(G, Solver, prec_G); But >> it seems that the precondition of linear_operator is not supported. Is >> there any solution? >> >> best >> Chen >> >> 在2022年4月18日星期一 UTC+8 22:07:36<[email protected]> 写道： >> >>> Bruno Turcksin >>> Thank you! it really helpful! >>> >>> best >>> chen >>> 在2022年4月18日星期一 UTC+8 21:07:45<[email protected]> 写道： >>> >>>> Chen, >>>> >>>> Yes, LinearOperator does support Trilinos and PETSc matrices. >>>> LinearOperator even supports your own matrix type as long as you define >>>> vmult and Tvmult (see here >>>> <https://dealii.org/current/doxygen/deal.II/group__LAOperators.html#ga6b74b7ed76e4aeea2c67c0bbb03e3e24> >>>> ) >>>> >>>> Best, >>>> >>>> Bruno >>>> >>>> On Monday, April 18, 2022 at 4:19:42 AM UTC-4 [email protected] wrote: >>>> >>>>> Hi everyone, >>>>> >>>>> When solving a block matrix system, the LinearOperator is a useful >>>>> tool. My question is whether the LinearOpertor supports Matrix type (the >>>>> same as the Vector type) like PETSCWrapper::MPI::SparseMatrix or >>>>> TrilinosWrapper::MPI::SparseMatrix? >>>>> >>>>> Best >>>>> Chen >>>>> >>>> > -- > The deal.II project is located at http://www.dealii.org/ > For mailing list/forum options, see > https://groups.google.com/d/forum/dealii?hl=en > --- > You received this message because you are subscribed to the Google Groups > "deal.II User Group" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/dealii/6ee40751-54ae-402d-903e-ae745545387bn%40googlegroups.com > > <https://groups.google.com/d/msgid/dealii/6ee40751-54ae-402d-903e-ae745545387bn%40googlegroups.com?utm_medium=email&utm_source=footer> > . > > > -- The deal.II project is located at http://www.dealii.org/ For mailing list/forum options, see https://groups.google.com/d/forum/dealii?hl=en --- You received this message because you are subscribed to the Google Groups "deal.II User Group" group. 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