Re: [deal.II] Resolving with different RHS

ing of the class could > address that issue. > > Best, > Jean-Paul > > On 02 Jun 2020, at 12:53, Andreas Kyritsakis > wrote: > > Thanks a lot!! > > On Tuesday, June 2, 2020 at 1:21:37 PM UTC+3, Simon Sticko wrote: >> >> Hi, >> a better option t

[deal.II] Re: Resolving with different RHS

rrent/doxygen/deal.II/classSparseDirectUMFPACK.html > > You might want to take a look at step 22, which uses this solver: > > https://www.dealii.org/current/doxygen/deal.II/step_22.html > > Best, > Simon > > On Tuesday, June 2, 2020 at 12:04:38 PM UTC+2, Andreas Kyritsakis wrote: >> &g

[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] problem measure() for quads

Thank you very much Wolfgang. Yes I would like to propose a patch. How is it done? I am not familiar with the process. On Thursday, May 28, 2020 at 7:31:04 PM UTC+3, Wolfgang Bangerth wrote: > > On 5/28/20 3:08 AM, Andreas Kyritsakis wrote: > > > > I have a problem with

[deal.II] problem measure() for quads

remained the same extremely low, which might result in unnecessary computational effort. I wonder whether the tolerance can be increased to something more reasonable (e.g. 1.e-10) or there is something I am missing that suggests such a low tolerance. Best regards, Andreas Kyritsakis -- The

[deal.II] Bug Report in GridTools::get_active_neighbors()

Hello, This is to report what I think is a bug in GridTools::get_active_neighbors(). The following code should compile but it does not. #include #include #include #include using namespace dealii; template class Test{ public: Test(Triangulation *tria) : triangulation(triangulation), d

Re: [deal.II] Axisymmetric problems

Wolfgang, > How does GetDP do that? Is it a global flag that is set once? In GetDP the user defines in the input script an object called "Jacobian", which can be different for each domain region. When setting up an integral term in the weak formulation then, you have to specify which jacobian

Re: [deal.II] Axisymmetric problems

Hi Wolfgang, Thank you very much. Your answer was very helpful. > You're correct -- the mapping classes don't do that. I also think that they > shouldn't: They have a different purpose and at least at the moment I don't > quite see how that could be put into what the mappings are supposed to

Re: [deal.II] Associating a MappingManifold with a Manifold

pass it where required. The manifold that is used is the one associated to > the triangulation. You don’t need to associate it to the Mapping, since the > mapping is used on *all* objects of the triangulation, and it will know how > to construct the data from the underlying manifold object

[deal.II] Associating a MappingManifold with a Manifold

Hi, I want to use a real-to-reference-cell mapping which corresponds to cylindrical symmetry in 2D. In other words, the integration jacobian and the shape function gradients should contain the scale factor of the cylindrical coordinates. I tried to do it with the following code: QGauss<2> q

Re: [deal.II] Axisymmetric problems

Wolfgang, Thank you very much for your prompt response. You are right that one could just leave the mapping as a simple 2D and change the weak formulation. However I think that it is possible to solve an axisymmetric problem without touching the weak formulation. I have been working for quite

[deal.II] Axisymmetric problems

lem is solved (e.g. just the laplace/poisson equation in such a domain). Such problems are very common and a lot of people would benefit from such a tutorial. Can anyone help in this? Thank you very much, Andreas Kyritsakis -- The deal.II project is located at http://www.dealii.org/ For mailin