Dear Daniel, I am sorry, my question truly was unclear. Let's say I solve a first equation for Velocity, and I would like to use this velocity in another equation for advection-diffusion of say Temperature. I would first set-up my DOF and FE system for my velocity equation and solve it and set-up by DOF and FE system for my Temperature. However, how would I be able to set up an additional space to store my velocity at the nodes that are related to my Temperature FESystem without introducing additional unknown in my temperature equations (Since velocity is known after all) and without assuming that both my temperature and velocity equation are numbered in the same exact fashion?
Best Bruno On Saturday, June 29, 2019 at 1:54:03 PM UTC-4, Daniel Arndt wrote: > > Bruno, > > Hello everyone, I hope you are well. >> I have a quick question which I cannot seem to wrap my hear around. I >> think it will sound confused, but anyway. >> Let's say I am solving for a scalar equation. I would have a >> triangulation, then a DoFHandler and a FESystem with a multiplicity of one. >> I can loop over the cells and assemble my equations. >> > If you only have a scalar equation, there is no need to use FESystem but > you can do that of course. > > >> Now, let's say I wanted to have an additional property that would be a >> vector defined at the nodes of my triangulation using the positions of the >> nodes. >> However, this vector would not be used to be interpolated at the gauss >> points, but would be use to cut the cells and do other geometric >> manipulations. >> I could define another DoFHandler , and FESystem, but then when I loop >> over the cells, there would be nothing to make sure that my DOF on both >> equations are numbered in the same way. >> However, I cannot defined another vector using the FESystem of my scalar >> equation, because the multiplicity is not the same. >> What would be the best way to proceed? >> > I am not quite sure to understand what you are asking for. The support > points only coincide for FE_Q(1) elements with the nodes of the > triangulation. > Normally, you would associate the entries of a Vector with the finite > element vector defined by the degrees of freedom (and the ansatz space), > but you can also store different information. > You are talking about two equations. What is the second equation and how > is it related to the first one? Can you give an example how you want to use > the Vectors? > > Best, > Daniel > -- 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 Groups "deal.II User Group" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/dealii/bf313a02-e47a-432b-8d7b-f3d4be42f8fc%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
