Re: [deal.II] Resolving with different RHS

Thank you both! On Tuesday, June 2, 2020 at 10:12:43 PM UTC+3, Jean-Paul Pelteret wrote: > > Hi Andreas, > > I concur with Simon. Additionally, if you’re using the Trilinos linear > algebra classes, then the TrilinosWrappers::SolverDirect solver will do the > same > > https://dealii.org/develope

Re: [deal.II] preconditioner for three block matrix

Dear Zeb, To expand on what Wolfgang said in his previous email, we have a page that provides some hints on how to formulate a question that you can then engage the community with. Please give it a read, and have another go at asking

Re: [deal.II] Resolving with different RHS

Hi Andreas, I concur with Simon. Additionally, if you’re using the Trilinos linear algebra classes, then the TrilinosWrappers::SolverDirect solver will do the same https://dealii.org/developer/doxygen/deal.II/classTrilinosWrappers_1_1SolverDirect.html#a6c0fecc921bc93f2c005e265cfbdd882

Re: [deal.II] preconditioner for three block matrix

On 6/2/20 2:58 AM, hussan zeb wrote: Dear Wolfgang Thanks for your reply , i want to solve for viscoelastic fluid Zeb, you'll have to be more specific. How about you show us the equations you want to solve, what others in the literature are doing, how you think that the solver/preconditioner

[deal.II] Re: Resolving with different RHS

Thanks a lot!! On Tuesday, June 2, 2020 at 1:21:37 PM UTC+3, Simon Sticko wrote: > > Hi, > a better option than computing the inverse is to factorize the matrix. > This can be done using the SparseDirectUMFPACK solver: > > > https://www.dealii.org/current/doxygen/deal.II/classSparseDirectUMFPACK.

[deal.II] Re: Resolving with different RHS

Hi, a better option than computing the inverse is to factorize the matrix. This can be done using the SparseDirectUMFPACK solver: https://www.dealii.org/current/doxygen/deal.II/classSparseDirectUMFPACK.html You might want to take a look at step 22, which uses this solver: https://www.dealii.org

[deal.II] Resolving with different RHS

Dear all, I have a problem where a Poisson-like equation has to be solved again and again in many time steps. At each timestep the LHS remains the same while the RHS changes (slightly). My current implementation is to use the standard SolverCG, passing the old solution as initial, which already

Re: [deal.II] preconditioner for three block matrix

Dear Wolfgang Thanks for your reply , i want to solve for viscoelastic fluid *''Oldryed-b fluid '' * *Best * *Zeb* On Mon, Jun 1, 2020 at 11:22 PM Wolfgang Bangerth wrote: > On 6/1/20 8:24 AM, hussan zeb wrote: > > > > how can solve preconditioner for 3x3 matrix inn step57 > > Hussan --