Nedelec elements

Question

I am trying to create the following matrix
$$ C_{i,j} = \begin{cases}
\pm 1 & \quad \text{if node $j$ is the head/tail of edge $i$,}
\
\quad 0 & \quad \text{otherwise}
\end{cases}
$$

This matrix depends on the global orientation of the Nedelec elements but I don't know how to extract these from the function space. Is this easily done?

Sorry about the poor LaTeXing but I can't seem to make it to have cases. Tried a bunch of ways and none of them work....

Answer 1

What do you mean by head and tail?

Comments

So I need the global tangential vector on each edge (this should come from the Nedelec space) then the head node would be the node at which the tangential vector is pointing to and the tail would be the other node.