Is it possible to access the edge matrices in FreeFEM++? How does do it in FreeFEM++?

What is edge matrices ?

if you want to have access of the edge numbering, the answer is yes.

```
mesh Th= square(10,10);
fespace Eh(Th,P0edge);// use a finite element on edge
for (k=0; k<Th.nt; ++k)
for (int e =0; e< 3;++e)
Eh(k,e) ; // number of edge e of triangle k
// the vertex of edges e1= (e+1)%3, e2= (e+2)%3 in triangle k.
```

Dear Prof. Hecht,

Thank you for your response, and my apologies for the very late reply to your comment.

The edge matrix corresponding to element K is given as follows:

E^K = [E^K_1, . . . , E^K_d] = [x^K_1 − x^K_0, . . . , x^K_d − x^K_0].

Here, the i-th column vector E^K_i = x^K_i −x^K_0, i=1,…,d, represents an edge of the triangle or element K.

Thank you.