Re: [deal.II] inverse operation to AffineConstraints.condense() (recovering full system matrix)

This makes sense. What do you think is an appropriate data structure for the storage of the entries associated with the constrained dofs? A FullMatrix or a separate AffineConstraints? Later, I have to somehow merge this data structure with the condensed system matrix since I have to solve a

Re: [deal.II] create reference simplex in 2d (triangle) based on three vertices

. Juli 2023 um 17:14:14 UTC+2: Mathieu, You should be able to use GridGenerator::reference_cell ( https://www.dealii.org/current/doxygen/deal.II/namespaceGridGenerator.html#aeb9a83e353f8d69ce49ebdd191a3a51f ), and then move the vertices to your liking, e.g. by using GridTools::transform ( https

[deal.II] create reference simplex in 2d (triangle) based on three vertices

Hello everyone, I read the simplex support documentation and was wondering whether it is possible to create a triangle in 2d based on three vertices? The quadrilateral pendant is GridGenerator::general_cell(). Contrary to

[deal.II] turning off tbb dependency without recompiling deal.II ?

Hello everyone, my question is a follow-up on this question that I created some weeks ago. In a nutshell, I want to link deal.II against matlab, which results in a segmentation fault. #include #include "MatlabEngine.hpp"

Re: [deal.II] linking dealii (compiled with MPI) to MATLAB engine results in segmentation fault

Maier schrieb am Freitag, 23. Juni 2023 um 06:48:35 UTC+2: > In the debugger after you ran with the command »r« could you please try > to generate a back trace with »bt«? > > (gdb) r > ... > (gdb) bt > ... > > Best, > Matthias > > > > On Thu, Jun 22, 202

Re: [deal.II] linking dealii (compiled with MPI) to MATLAB engine results in segmentation fault

ebugger such as > gdb? If possible, the stacktrace for the segfault will be very > illuminating: > > $ gdb executable > > run > > bt > > Best, > Matthias > > > > On Thu, Jun 22, 2023, at 14:46 CDT, Mathieu wrote: > > > Thanks Matthias for clarification. >

Re: [deal.II] linking dealii (compiled with MPI) to MATLAB engine results in segmentation fault

ttwoch, 21. Juni 2023 um 23:53:06 UTC+2: On 6/21/23 11:42, Mathieu wrote: > > I compiled dealii with MPI and the cxx compiler found by cmake is from > openmpi-4.1.3. > I narrowed my program down and installed dealii without any dependencies > to use the default cxx compiler on

[deal.II] linking dealii (compiled with MPI) to MATLAB engine results in segmentation fault

Hello everyone, within my dealii program, I want to do some tasks using matlab functions, i.e., I want to call matlab functions/scripts from within my dealii (.cpp) program. To this end, I modified my top-level CMakeLists.txt, included the headers #include "MatlabDataArray.hpp" #include

Re: [deal.II] Re: evaluation FE function outside domain

larify one last thing: The gradient (deriv. with regards to x and y) of the above extrapolation is given by [ grad_T[0]; grad_T[1] ]. Correct? -Math Am Fr., 9. Juni 2023 um 17:39 Uhr schrieb Wolfgang Bangerth < bange...@colostate.edu>: > On 6/9/23 09:24, Mathieu wrote: > > >

Re: [deal.II] evaluation function and its gradient after rotating the triangulation

i 2023, 22:59: > On 6/9/23 12:52, Mathieu wrote: > > > > The fact that f^h is no longer separated changes the solution of my pde > > drastically: > > If I run my program with the analytical f or with f^h on the axis > parallel > > grid, the output is quite similar.

Re: [deal.II] evaluation function and its gradient after rotating the triangulation

workaround for this issue , right? Best, Math Wolfgang Bangerth schrieb am Fr., 9. Juni 2023, 17:45: > On 6/9/23 09:14, Mathieu wrote: > > > > I would have to refine the rotated grid roughly seven times to > approximate > > this decoupling accurately. > > Unfor

Re: [deal.II] Re: evaluation FE function outside domain

g Bangerth < bange...@colostate.edu>: > On 6/9/23 08:27, Mathieu wrote: > > > > Say, P=(Px,Py) is the point outside the domain, > > T=(Tx, Tx) the closest vertex at the boundary as computed above, > > and grad_T the gradient of the finite element function at T. >

Re: [deal.II] evaluation function and its gradient after rotating the triangulation

" No, it isn't. What you are plotting is the *interpolated* version of the function. As a consequence... ...this should not be a surprise unless you can convince that the *interpolated* function should be the same in both cases. This is a question about the function f(x,y) you use: Is it in the

Re: [deal.II] Re: evaluation FE function outside domain

value at P as f(P) = f(T) + grad_T[0]*(Px-Tx) + grad_T[1]*(Py-Ty). Is that reasonable? Thanks, Math Am Fr., 9. Juni 2023 um 00:49 Uhr schrieb Wolfgang Bangerth < bange...@colostate.edu>: > On 6/7/23 11:42, Mathieu wrote: > > A bilinear extrapolation seems to be a suitable fi

Re: [deal.II] Re: evaluation FE function outside domain

to the closest at the boundary of the triangulation and evaluate the gradient there. So, given P, how can I find the closest point at the boundary? Or would you choose a different point at the boundary? -Math Wolfgang Bangerth schrieb am Mi., 7. Juni 2023, 19:23: > On 6/7/23 10:57, Mathieu wr

Re: [deal.II] Re: evaluation FE function outside domain

e boundary. Any suggestions? Thank you, Math Wolfgang Bangerth schrieb am Mittwoch, 7. Juni 2023 um 16:33:32 UTC+2: > On 6/6/23 14:24, Mathieu wrote: > > > > for a post-processing step, I have to evaluate my temperature field at > some > > points outside the mesh clos

Re: [deal.II] Re: evaluation FE function outside domain

g to achieve? > > Best, > > Bruno > > On Monday, June 5, 2023 at 4:59:28 PM UTC-4 Mathieu wrote: > >> Hello everyone, >> >> I was wondering if deal.II has built-in functions to evaluate continuous >> finite element functions (FEQ) at points outside the mesh?

[deal.II] evaluation FE function outside domain

Hello everyone, I was wondering if deal.II has built-in functions to evaluate continuous finite element functions (FEQ) at points outside the mesh? E.g.: given a point P in 2d/3d, which is not contained in the 2d/3d mesh but close to the boundary, how could one evaluate (extrapolate) the FE

[deal.II] determine global dof index of a point

Hello everyone, I apologize for my simple question: Given a point, which is also a vertex (support point of FE_Q element), in real coordinates, is there a function that allows me to query the global dof index associated with that support point? I know all the cells at which these support point

[deal.II] find all vertices connected to a given vertex

Hello everyone, I have a 2d grid (no hanging nodes) where a scalar finite element field is defined on it (i.e., one degree of freedom per support point). For all vertices defined on that grid, I want to get the global dof indices of all connected vertices. E.g.: an vertex inside the grid has

[deal.II] Question on step-33

I am trying to implement a shallow water equation solver in Deal-ii. I took step-33 as basis and I have some questions with the MPI-parallelization. Apparently using the MPI parallelization has no effect in step-33, only on the solver. Only step-17 has a if (cell->subdomain_id() ==