Re: [deal.II] How to access solution values at DoFs of a cell?

You are right. I only need values or grad values at the quadrature points. Thanks a lot. --Junchao Zhang On Fri, Jul 22, 2016 at 6:52 PM, Wolfgang Bangerth wrote: > On 07/22/2016 05:10 PM, Junchao Zhang wrote: > >> In matrix assembly, I need to access solution values of the previous >> time-

Re: [deal.II] How to access solution values at DoFs of a cell?

On 07/22/2016 05:10 PM, Junchao Zhang wrote: In matrix assembly, I need to access solution values of the previous time-step at DoFs of the current cell. Is my following code correct? I could not find an example. Thanks. std::vector local_dof_indices (dofs_per_cell); ... for(; cell!=endc

[deal.II] How to access solution values at DoFs of a cell?

Hi, In matrix assembly, I need to access solution values of the previous time-step at DoFs of the current cell. Is my following code correct? I could not find an example. Thanks. std::vector local_dof_indices (dofs_per_cell); ... for(; cell!=endc; ++cell) { if (cell->is_locally_owned())

[deal.II] Re: How to apply boundary constraints in time-dependent and adaptive code?

On Friday, July 22, 2016 at 4:16:47 PM UTC-5, Daniel Arndt wrote: > > Junchao, > > >>> The interpolated solution should already have the correct (old) boundary >>> conditions. >>> >> Is it true? As you see, I call >> constraints.distribute(interpolated_solution) to impose boundary >> constrain

[deal.II] Re: How to apply boundary constraints in time-dependent and adaptive code?

Junchao, >> The interpolated solution should already have the correct (old) boundary >> conditions. >> > Is it true? As you see, I call > constraints.distribute(interpolated_solution) to impose boundary > constraints, which are computed in setup_system() as follows > What I meant to say is tha

Re: [deal.II] Re: Decoupling FECollection and QCollection

Well, I guess it's a question of how one should interpret this sentence. Anyway, if you want to avoid calling reinit with extra parameters during assembling (might be simpler anyway) you can probably achieve the same thing by adding the same element twice to FECollection. For example: fe_colle

[deal.II] Re: How to apply boundary constraints in time-dependent and adaptive code?

On Friday, July 22, 2016 at 12:50:56 PM UTC-5, Daniel Arndt wrote: > > Junchao, > > For what matters here, you are just interesting in how to deal with > boundary constraints for a time-dependent problem. > > I am not quite sure what your problem is. You have time-dependent boundary > condition

[deal.II] Re: How to apply boundary constraints in time-dependent and adaptive code?

Junchao, For what matters here, you are just interesting in how to deal with boundary constraints for a time-dependent problem. I am not quite sure what your problem is. You have time-dependent boundary conditions so you want to use boundary conditions corresponding to the correct time step. Wh

Re: [deal.II] Re: Decoupling FECollection and QCollection

Dear Deepak, Its possible that the initial implementation of the functionality has changed, and that this part of the documentation was accidentally not updated. As best as I can tell, this sentence is referring to the default case where q_index and fe_index are not going to be prescribed (in w

Re: [deal.II] Re: Decoupling FECollection and QCollection

Dear Simon Thanks for the reply. I was guessing the same, but then this sentence from the documentation seems a bit ambiguous. Isn't it? "/The quadrature rules have to be added in the same order as for the FECollection

[deal.II] Re: Decoupling FECollection and QCollection

Hi, When you call reinit on hp::FEValues you can send in which of the elements in the collection you want to reinitialize with. That is, when you call reinit you call it as fe_values.reinit(cell, q_index, mapping_index, fe_index); where the additional integers specify which element in the colle

Re: [deal.II] Re: Amesos_Superludist with TrilinoWrappers bad performance

Marek, 2016-07-22 2:42 GMT-04:00 Vinetou Incucuna : > Therefore ad1) is split into small subsystems (approximately 2000 > unknowns for each core) and therefore the Amesos_Superludis should > have worked nicely? Yes SuperLU should work on this problem but I think that there is some confusion here.

Re: [deal.II] Re: Amesos_Superludist with TrilinoWrappers bad performance

On Fri, Jul 22, 2016, at 07:20 CDT, Vinetou Incucuna wrote: > Matthias, just to make things clears. What everything > should be build in release mode - deal.ii, trilinos (and > dependency libraries Blas, Lapack) > , SuperLU_Dist ? > I will give a try on Dofs renumbering. The deal.II library is

Re: [deal.II] Re: Amesos_Superludist with TrilinoWrappers bad performance

Matthias, just to make things clears. What everything should be build in release mode - deal.ii, trilinos (and dependency libraries Blas, Lapack) , SuperLU_Dist ? I will give a try on Dofs renumbering. Thank You M 2016-07-22 13:43 GMT+02:00 Jean-Paul Pelteret : > Also, have you tried optimisin

Re: [deal.II] Re: Amesos_Superludist with TrilinoWrappers bad performance

Also, have you tried optimising the bandwidth of the sparse system by renumbering the DoFs ? On Friday, July 22, 2016 at 12:30:01 PM UTC+2, Matthias Maier wrote: > > > I have the feeling, that my setup is the root cause

Re: [deal.II] Re: Amesos_Superludist with TrilinoWrappers bad performance

> I have the feeling, that my setup is the root cause of poor performance > of both solve and assemble (3s for assemble in release mode for 2000 dofs > is according to my opinion slow [17s in debug mode]). Have you run your computations against the debug library, or against the optimized release l

Re: [deal.II] Re: Amesos_Superludist with TrilinoWrappers bad performance

Hello, I have the feeling, that my setup is the root cause of poor performance of both solve and assemble (3s for assemble in release mode for 2000 dofs is according to my opinion slow [17s in debug mode]). Could You look at following stripped snippets of setup, solve and assemble, and give me ad