Re: [deal.II] how to treat the intersection point at the first and second kined bcs

2023-11-13 Thread ztdepyahoo
I mean one boundary has the first kind bc, while the second has neumann bc.  so What is the bc for the intersection nodes.  ztdepyahooztdepya...@gmail.com

Re: [deal.II] How to convert stiffness matrix in global degrees of freedom into stiffness matrix in global cells

2023-11-13 Thread Lance Zhang
Hello Wolfgang, thanks very much for your information. I got the point. Best regards Lance Wolfgang Bangerth 于 2023年11月13日周一 21:01写道: > > On 11/13/23 03:05, Lance Zhang wrote: > > > > I wonder whether the stiffness matrix could be converted to a matrix > > with rows = cell_numbers and

Re: [deal.II] How to convert stiffness matrix in global degrees of freedom into stiffness matrix in global cells

2023-11-13 Thread Wolfgang Bangerth
On 11/13/23 03:05, Lance Zhang wrote: I wonder whether the stiffness matrix could be converted to a matrix with rows = cell_numbers and columns = cell_numbers. Lance: I think I mentioned this before: You can't. The entries of the stiffness matrix are sums over contributions from different

[deal.II] deal.II Newsletter #269

2023-11-13 Thread 'Rene Gassmoeller' via deal.II User Group
Hello everyone! This is deal.II newsletter #269. It automatically reports recently merged features and discussions about the deal.II finite element library. ## Below you find a list of recently proposed or merged features: #16265: Look-up table for Hermite (proposed by ivweber)

Re: [deal.II] how to treat the intersection point at the first and second kined bcs

2023-11-13 Thread Wells, David
Hi there, People use many different boundary conditions with deal.II - e.g., step-22 sets the normal component of the normal stress to zero, whereas many other tutorial programs use Dirichlet or Neumann boundary conditions. Which two boundary conditions are you referring to? Best, David Wells

Re: [deal.II] Raviart-Thomas elements on shells in 3D

2023-11-13 Thread blais...@gmail.com
If you need any help, feel free to reach out to the deal.II community, we are always glad to help On Sunday, November 5, 2023 at 10:37:42 a.m. UTC-5 M. Bakry wrote: > Dear Wolfgang, > > thanks very much for your answer. I think I will give it a try when I > find some time. Non-C1 manifolds

Re: [deal.II] In example 40, the results are significantly different between the first-order and second-order finite element meshes

2023-11-13 Thread blais...@gmail.com
Changing to Fe1 really alters the solution, so consequently the kelly error estimator will also give you a different error estimation and thus a different mesh adaptation. If your mesh adaptation is based on an error estimator, altering the finite element interpolation order will alter the

Re: [deal.II] How to convert stiffness matrix in global degrees of freedom into stiffness matrix in global cells

2023-11-13 Thread Lance Zhang
Hello Wolfgang, thanks for your reply. I wonder whether the stiffness matrix could be converted to a matrix with rows = cell_numbers and columns = cell_numbers. I tried to write the gradient with rows = degree_of_freedom into with rows = cell_numbers. ### for (unsigned int i =