[Libmesh-users] DG implementation

[Rossi, S. <sr...@em...>]

Dear all,
I’m trying to implement a DG formulation for solid mechanics using linear elements.

I’m currently using the following strategy:
I define my variables as MONOMIALS but in the assembly I pretend my FEType is LAGRANGE.
This gives me the correct values of the shape functions on the edges.
I was also able to use the L2_LAGRANGE family to achieve the same results.
Do you have any suggestions on which family I should use?

Additionally I noticed something wrong in the assembly.
When I use LAGRANGE fefamily my global rhs vector (for a 2D elasticity problem) looks like this

u_x_point0
u_y_point0

u_x_point1
u_y_point1

.
.
.

u_x_pointN
u_y_pointN

and the local vector is organized in the following manner

u_x_point0
u_x_point1
u_x_point2

u_y_point0
u_y_point1
u_y_point2

Does this still happen with other fefamilies? 
My routine for assembly of traction boundary conditions works with LAGRANGE fefamily. For a 2D square with 2 elements and a shear traction condition my rhs is

RHS!
Size	global =  8		local =  8
#	Value
0	0
1	0
2	0
3	3.125
4	0
5	3.125
6	0
7	0

When using MONOMIALS or L2_LAGRANGE ,  I think the contributions are in the wrong  places

RHS!
Size	global =  12		local =  12
#	Value
0	0
1	0
2	0
3	0
4	3.125
5	3.125
6	0
7	0
8	0
9	0
10	0
11	0

Does anyone have any suggestion?
Thank you very much for your help,

All the best,
Simone