grouping Planner and Line elements in dealii

[asim khan]

Dear users,

I am trying to implement my finite element model in dealii. the weak form of my problem is 

where as 

and Ti is some internal boundary in the domain. My idea was to implement it using the method use in the example 46 and followed as 

1) i made two seperate domains in gmash and marked the elements on the seleted edge with material_id =left and material_id=right.

2) I merged them to the single triangulation so the material id information is transfered to the new mesh with all outboundary id = 0

3) i want to loop over the cell with material id=left and check that if cell->face->neighbour-cell ->material_id=right 

than do the face integration on the face. but i did not found any function that can check neighbour-cell material id.

Is there any easy way to do this problem or any alternate suggestion.

and second thing I also wish to add some stiffness to some node. can i mark the node for this purpose to add some stiffness to stiffness matrix.

thanks in advance

asim khan