Menu

Discussion Forum

New Discussion
Filter

Note: This discussion is about an older version of the COMSOL Multiphysics® software. The information provided may be out of date.

Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.

Where are the points corresponding to DOFs?

Posted Jul 20, 2014, 11:53 p.m. EDT Geometry, Mesh, Parameters, Variables, & Functions, Results & Visualization Version 4.3b 0 Replies

Evgeni Sergeev
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Based on previous posts, it seems that:

1. Different dependent variables may use different points with respect to the element (Lagrange points or Gauss points perhaps).

2. Quoting Ivar from www.comsol.com/community/forums/general/thread/35948/#p99445 :
[...] A 2nd order discretization, is close to saying you add a virtual node between each mesh physical node [...]

3. This blog post essentially confirms the above www.comsol.com/blogs/meshing-considerations-linear-static-problems/ (and has diagrams).


Is there a way to determine what are the points corresponding to degrees of freedom in a given simulation?

I have just exported (Results > Export > Data > Solution 1, Lagrange points, Resolution: Fine) from an Electric Current 2D simulation and got the same number of points as the degrees of freedom reported by Comsol when solving. It looks like the grid of mesh nodes is subsampled when I select Resolution: Fine, but I just get the mesh nodes with Resolution: Normal.

Do these "Fine" Lagrange points correspond exactly with the DOF points, or is it just a coincidence that there is the same number of them?

More importantly, is this documented somewhere officially? (I need to know the DOF points to apply a post-processing solution accuracy/error estimation technique based on GCI.)
0 Replies Last Post Jul 20, 2014, 11:53 p.m. EDT
COMSOL Moderator

Hello Evgeni Sergeev

Your Discussion has gone 30 days without a reply. If you still need help with COMSOL and have an on-subscription license, please visit our Support Center for help.

If you do not hold an on-subscription license, you may find an answer in another Discussion or in the Knowledge Base.

Note that while COMSOL employees may participate in the discussion forum, COMSOL® software users who are on-subscription should submit their questions via the Support Center for a more comprehensive response from the Technical Support team.

Suggested Content