[deal.II] Re: How to compute convergence rate of L2 norm of error without exact solution? And how to compute convergence rate of in different golobally refinement?

Dear Prof. Arndt, I have used SolutionTransfer as you say, but if I set a phi_0 fixed, then project it into finite element space and get a vector phi_0_h, then I get phi_0_h/2, phi_0_h/4, phi_0_h/8 by using SolutionTransfer, but the norm of (phi_0_h- phi_0_h/2), (phi_0_h/2- phi_0_h/4),

[deal.II] Re: How to compute convergence rate of L2 norm of error without exact solution? And how to compute convergence rate of in different golobally refinement?

Dear Prof. Arndt, I have used SolutionTransfer as you say, but if I set a phi_0 fixed, then project it into finite element space and get a vector phi_0_h, then I get phi_0_h/2, phi_0_h/4, phi_0_h/8 by using SolutionTransfer, but the norm of (phi_0_h- phi_0_h/2), (phi_0_h/2- phi_0_h/4),

[deal.II] Re: How to compute convergence rate of L2 norm of error without exact solution? And how to compute convergence rate of in different golobally refinement?

Dear Prof.Arndt, Thank you very much! I understand what you say. It helps me a lot! Best, Chucui 在 2019年2月21日星期四 UTC+8下午7:31:20，Daniel Arndt写道： > > Chucui, > > > For Question 1, I write a code to compute the L2 norm of (solution_1 - >> solution_2): >> [...] >> >> Is that right? >> > You can

Re: [deal.II] How to compute convergence rate of L2 norm of error without exact solution? And how to compute convergence rate of in different golobally refinement?

Dear Jean-Paul, Thank you very much for your quick reply! I will read it now! Best, Chucui 在 2019年2月21日星期四 UTC+8下午5:17:17，Jean-Paul Pelteret写道： > > Hi Chucui, > > I can only offer you a very brief reply right now: You might want to look > into the ConvergenceTable >

[deal.II] Re: How to compute convergence rate of L2 norm of error without exact solution? And how to compute convergence rate of in different golobally refinement?

Hi, all, If there is no function to compute convergence above, I need to write the code by myself. For Question 1, I write a code to compute the L2 norm of (solution_1 - solution_2): template double StokesProblem::norm_compute (const Vector solu_1,

[deal.II] How to compute convergence rate of L2 norm of error without exact solution? And how to compute convergence rate of in different golobally refinement?

Hi all, I have 2 questions of computing convergence rate of L2 norm of error: 1. If I don't have exact solution, does deal.ii have functions to compute convergence rate directly? (Like VectorTools::integrate_difference, which deals with the problem with exact solution ) 2. If I want to

Re: [deal.II] different results when compute integration with adaptive mesh

Dear Jean-Paul, Thank you very much for you answer! It helps me a lot. The attached is the implemention of your idea, and the result is: Cycle 0: Number of active cells: 20 Number of degrees of freedom: 89 u_square: 0.0305621 grad_u_square: 0.256542 Cycle 1: Number of active

Re: [deal.II] different results when compute integration with adaptive mesh

Dear Jean-Paul, Thank you very much for your detailed answer! I will write it as you say right now and report the results as soon as possible ! Best, Chucui 在 2019年2月12日星期二 UTC+8下午3:26:34，Jean-Paul Pelteret写道： > > Dear Chucui, > > Too add to all of the other comments, you can "sanity check”

Re: [deal.II] Re: different results when compute integration with adaptive mesh

Dear Prof. Bangerth, Thanks very much for your quick answer! > Constraints are funny and sometimes require deep thought about what exactly > they mean. What happens if you don't apply constraints to the > cell_volume_matrix and cell_gradient_matrix -- i.e., you copy the elements 1:1 > into

Re: [deal.II] Re: different results when compute integration with adaptive mesh

Dear Prof Arndt, Thanks for your quick answer! > in the end you program is very similar to step-6. Do you observe the same behavior there as well? Yes, my code add several lines below to step-6.cc directly: ... SparseMatrix volume_matrix; SparseMatrix gradient_matrix; ...

Re: [deal.II] Re: different results when compute integration with adaptive mesh

Dear Prof. Bangerth: Thank you very much for your quick reply! When I apply hanging node constraints to my matrix, as the step-6 says: https://www.dealii.org/developer/doxygen/deal.II/step_6.html I make 4 steps: 1.Create a Constraints Class: ConstraintMatrix constraints; 2.Fill

[deal.II] Re: different results when compute integration with adaptive mesh

The attach is the code for refine global. 在 2019年2月11日星期一 UTC+8上午11:21:00，chucu...@gmail.com写道： > > Dear Prof. Bangerth, >> > > Thanks for your quick reply! > > > You mean you are wondering why the "grad u square" term grows with the > size of the problem but "u square" does not? > > Yes,

[deal.II] Re: different results when compute integration with adaptive mesh

> > Dear Prof. Bangerth, > Thanks for your quick reply! > You mean you are wondering why the "grad u square" term grows with the size of the problem but "u square" does not? Yes, that's what I am confused. Our u_exact have exact "grad u_exact square" and "u_exact square". And our

[deal.II] different results when compute integration with adaptive mesh

Hi all, I have a very simple question but cannot think out: I use step-6.cc to implement different adaptive mesh, and solve u with each mesh. Then I want to compute : [image: ask-7.JPG] But there is a big gup on the results of the integration of the square of grad u: Cycle 0: Number of

[deal.II] Re: Implement of adaptive mesh refinement cannot work in time-dependent problem.

Dear Prof. Arndt, Thank you very much! >when the solver fails to converge within 1000 iterations. This is just because my solver code is : template void StokesProblem::solve_preconditioner () { SolverControl solver_control (1000, 1e-8*system_rhs.l2_norm()); SolverGMRES >

[deal.II] Re: Implement of adaptive mesh refinement cannot work in time-dependent problem.

Dear Prof. Arndt, Thanks for your quick answer! In my deal.ii (version 8.5.1), the code also fails in the 9th time step. Shall I need to reinstall my deal.ii into the newest version? For the shortest test code, please give me some time. Because I have deleted about 2000 lines. If I delete

[deal.II] Re: Implement of adaptive mesh refinement cannot work in time-dependent problem.

Dear Prof. Wolfgang, Thank you very much for your quick answer! I have thinked about your answers and debuged my code these days, and my question No.1 is still unsolved, and question No.2 has been solved: question No.1 : how to destroy sp efficiently? (unsolved) As you say, I can destroy

[deal.II] Re: Implement of adaptive mesh refinement cannot work in time-dependent problem.

Dear Prof. Wolfgang, Thank you very much for your quick answer! And I have tried what you say, and I have some questions still: 1. > In your case, a > SparsityPattern is still used by some other object but is being destroyed. > You'll have to find out what other object that is -- likely a

Re: [deal.II] How to compute the cellwise error of the finite element solution without exact solution?

Dear Prof. Bangerth, Thank you very much! FEFieldFunction fe_function_finest (dof_handler_finest, solution_finest ); And I can use the fe_function_finest in function: VectorTools:: integrate_difference And now I have another question: I want to compute numerical solutions in different widths

[deal.II] Re: How to restart a time dependent code from its breakpoint?

Dear Jean-Paul and dear Stephen, Thank you for your reply! As the examples you set, and an answer I found: See "Use for serialization" in

Re: [deal.II] How to restart a time dependent code from its breakpoint?

Dear Jean-Paul, Thank you for your reply! As the examples you set, and an answer I found: See "Use for serialization" in

[deal.II] How to compute the cellwise error of the finite element solution without exact solution?

Dear all, If I don't have the exact solution, but I want to compute the L2 form of u_{h}-u_{finest} (i.e. see u_{finest} as the exact solution, and u_{finest} is the numerical solution with the finest mesh grid among the series we want to test, for example, the width of the unit meshgrid is h

Re: [deal.II] How to restart a time dependent code from its breakpoint?

Dear Jean-Paul, Thanks for your reply! And I am interested in 'the serialization capabilities', can you give me a little example or code to show me how it work. For me the ASPECT library

[deal.II] How to restart a time dependent code from its breakpoint?

Hi All, I am running a code where the system I want to solve is time-dependent, which means: [image: 快快快.JPG] So, I want to solve u_{n+1} by using u_{n} in each time step n. If my code is broken suddenly ,at time step n=1000 for example, how to restart it from time step t_n = 1001, not t_n=1?

Re: [deal.II] Re: After "make install", there are some Errors when install Deal.II-9.0.1

Dear Wolfgang, Thanks for your advice, and Matthias's. Thank you very much! > > > I don't think any of us has seen this error before. Can you try what > happens if you delete the build directory, re-create it, and then just > use the minimal command line >cmake /vol7/... > ? Make things

[deal.II] Re: After "make install", there are some Errors when install Deal.II-9.0.1

Dear Matthias, The newest result are still the same. After "make install" it shows: [ 82%] Built target obj_rol_debug Scanning dependencies of target step-3.release [ 82%] Building CXX object examples/CMakeFiles/step-3.release.dir/step-3/step-3.cc.o [ 82%] Linking CXX executable

Re: [deal.II] Re: After "make install", there are some Errors when install Deal.II-9.0.1

Dear Matthias, I am sorry to delete the originial file and configure it again, but everything seems not change. And attached is the newest detailed.log. Thank you very much! Best, Chucui 在 2018年10月19日星期五 UTC+8上午11:53:35，Matthias Maier写道： > > > On Thu, Oct 18, 2018, at 17:48 CDT, David Wells

[deal.II] After "make install", there are some Errors when install Deal.II-9.0.1

Dear all, I want to reinstall my deal.ii because I need to run some codes in parallel just like Step-40, step-55 and Step-32, and I choose deal.ii-9.0.1 The command lines I use are: $cmake ../dealii-9.0.1/dealii-9.0.1 -DDEAL_II_WITH_MPI=ON -DCMAKE_C_COMPILER=/usr/local/mpi3/bin/mpicc

[deal.II] Re: How to plot a function including "arctan" correctly?

Dear Wolfgang, Thank you very much! >> So, my questions are: >> 1.If I need to get >> >> 4.JPG >> >> >>in every time step, which means that phi_x and phi_y are updated in >> every time step, and the information of phi_x and phi_y are calculated >> from "phi" by using function:

[deal.II] Re: Behavior of FESystem with 2 vectors and 2 scalars

Dear Daniel， Thank you very much! My questions are all solved. Best, Chucui -- 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

[deal.II] Re: Behavior of FESystem with 2 vectors and 2 scalars

The attachment are 2 code files：LittleCase0-4.cc (for test), LittleCase0-5.cc (RT element). 在 2018年8月26日星期日 UTC+8下午8:32:40，chucu...@gmail.com写道： > > Hi, All, > > I have a question of behavior of FESystem with 2 vectors and 2 scalars, my > original problem is to solve: > > [image: 56.JPG] > for

[deal.II] Behavior of FESystem with 2 vectors and 2 scalars

Hi, All, I have a question of behavior of FESystem with 2 vectors and 2 scalars, my original problem is to solve: [image: 56.JPG] for \phi, \sigma, \mu, \gamma, I choose FESystem to describe the information of them FESystemfe; [...] fe (FE_DGQ(degree), 1,

[deal.II] If I define two FESystem , how to use "FEValuesExtractors" separately？

Hi, all I have a simple question: if I define two FESystem: [...] FESystemfe_1; FESystemfe_2; [...] fe_1 (FE_Q(degree), 1, FE_Q(degree), 1), fe_2 (FE_RaviartThomas(degree), 1), [...] when I need to use "FEValuesExtractors" separately, how to define

[deal.II] Re: implemention of periodic boundary condition

Dear Daniel and Wolfgang, Thank you very much! In fact, I only want the gradient of periodic, not the Dirichlet periodic boundary. I thought they are same in periodic boundary conditions before, i.e. all informations of the solution on the face pairs are same. Now, I get that I have made

[deal.II] Re: implemention of periodic boundary condition

Dear Daniel, Thank you very much! I can test my period boundary condition added truly. Your advision helps me a lot ! As my question is about periodic boundary condition like [image: 42.JPG] just like Dirichlet boundary condition. But if "periodic boundary condition" means that all

[deal.II] Re: implemention of periodic boundary condition

Dear Daniel, Thank you very much! I use code like this: constraints.distribute_local_to_global(local_matrix, local_dof_indices, system_matrix) as you say, and use codes like this constraints.distribute(solution); after every "solve()" step. and now, my LittleCase0-3.cc can run. Maybe a

[deal.II] Re: implemention of periodic boundary condition

Dear Jean-Paul, Thank you very much for your patience, when I print some information like this: template void Problem::run () { [...] setup_dofs (); std::cout << "test-1 "<< std::endl; VectorTools::project (dof_handler_0, constraints_phi,

[deal.II] Re: implemention of periodic boundary condition

Dear Daniel, I'm sorry to make this mistake, (and thank Jean-Paul very much). The newest code focus on build the sparsity pattern in "setup_dof()", while other parts (assemble_system(), assemble_rhs(), run() ) need to be left to make the code work and maintain the structure of 3 components of

[deal.II] Re: implemention of periodic boundary condition

Dear Daniel, Thank you very much! The LittleCase0-3.cc is my work case with the same problem as I say. Simply describe what this code work for: to solve from

[deal.II] Re: implemention of periodic boundary condition

Dear Daniel, Thank you very much for your rapid reply! I use overload as you say, and it can run before assemble_system, the relevant part of my code is template void Problem::run

[deal.II] Re: implemention of periodic boundary condition

Dear Daniel, Thank you very much for your rapid reply! I use overload as you say, and it can run before assemble_system, the relevant part of my code is template void Problem::run

[deal.II] Re: implemention of periodic boundary condition

Dear Jean-Paul, Thank you very much! I had read step-45, but still have some questions: 1. How to use function "DoFTools::make_periodicity_constraints() " only? if my code need not to compute parallel case. If I choose void DoFTools::make_periodicity_constraints ( const FaceIterator & face_1,

[deal.II] Re: implemention of periodic boundary condition

Hi All, I am working on this project and find some problems new: 1. Why the source code of function "GridTools::collect_periodic_faces" use " cell_iterator" rather than "active_cell_iterator"? As I need to refine my domain by triangulation.refine_global (7); in

[deal.II] Re: when make, something about libgfortran may be wrong

After cmake -DDEAL_II_DIR=~/dealii-8.5.1/deal.II, the results is

[deal.II] Re: when make, something about libgfortran may be wrong

And this is my code: #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include

Re: [deal.II] implement weak formulation of biharmonic equation

I want to implement grad(delta_u), but shape_grad_component() is function in Class FEValuesBase, and it can't be used in delta_u directly, so I want to let delta_u be an object in Class FECaluesBase. 在 2018年2月28日星期三 UTC+8上午8:51:11，Wolfgang Bangerth写道： > > On 02/27/2018 05:44 PM,

Re: [deal.II] implement weak formulation of biharmonic equation

delta_u.shape_value_component(j,k,d) = trace(hessian_phi_u); ^ make[2]: *** [CMakeFiles/practice4order39.dir/practice-4order-39.cc.o] Error 1 make[1]: *** [CMakeFiles/practice4order39.dir/all] Error 2 make: *** [all] Error 2 I wander if my idea is c

Re: [deal.II] implement weak formulation of biharmonic equation

Dear Timo, Thank you very much! And I correct what you say, then "make" can go, but "make run" have error, and I don't understand what it mean and how to do: yucan@ubuntu-csrc-b224:~/boost/deal.II/examples/practice-4order-39$ make run [ 50%] Built target practice4order39 [100%] Run with Debug

Re: [deal.II] implement weak formulation of biharmonic equation

Dear Timo, Thank you very much! And I correct what you say, then "make" can go, but "make run" have error, and I don't understand what it mean and how to do: yucan@ubuntu-csrc-b224:~/boost/deal.II/examples/practice-4order-39$ make run [ 50%] Built target practice4order39 [100%] Run with Debug

[deal.II] implement weak formulation of biharmonic equation

Dear all, I want to solve biharmonic equation problem with interior penalty method like step-39, but I need to rewrite weak formulation. In step-39, it use functions like LocalIntegrators::Laplace::cell_matrix