How to assign data only on the edges of a 3D mesh

General Discussion
1

Dear Freefem team, I hope all of you doing great. I was wondering if there is any way I can only give a number to the points on the edges of a 3D mesh. I noticed that ,in Freefem, we can use ThS= Th.gamma to get the surface of 3D mesh. Then the edges ThL can be get from ThS by ThS.gamma as well. Initially, I attempted interpolate the data from MeshL to 3D mesh. However, it seems doesn’t work. I am attaching the code here, which shows the steps I mentioned above. Thank you so much for you time.
FREE_FEM_01.zip (3.0 MB)

2

I Sorry a try your exemple, I see not problem,
And I do not understand what you want to do.

3

Dear frederic, thank you for your time. In the demo, we did not put the interpolation over there. Basically, what am trying to do is:" fespace Vh(Th,P0); Vh ThreeD; fespace VhL(ThL,P0) oneDedge;
oneDedge = 1; ThreeD = oneDedege; " I thought ThreeD will only have 1 on the edges, and any other place will give 0; However, ThreeD has 1 everywhere. Thank you.

4

OK, the big problem in you all is: the dof of Vh is the barycenter of tet so no way by this way.

You can use P0edge finite element with dof are the barycenter of edge.

5

Thank you, If there is any example I can find from online?

6

I will try to fluid a simple example, but a find bug buildBdMesh function
zcwang6.edp (562 Bytes)

I try to correct rapidly

7

Thank you Frederic !!

8

I fact, They no error except in my graphic interpretation.

This code build a finite element function on edge U3

value = 1 on edge on edge of the cube
value = 0 on all other edge of the mesh.

zcwang6-v2.edp (740 Bytes)

9

Thank you so much, sir.