[Getfem-users] Matricial diffusion coefficient values on elements

[marco trevisan]

Hello,
I have a 2D diffusion problem defined on a regular square mesh, and am
using the Matlab interface.
Since I need to model strong diffusion anisotropies along the domain,
I defined a diffusion matrix for each dof (the dofs correspond exactly
to the vertices of the sequare elements of the mesh- i.e. the
convexes). Now, when the integrals are calculated during the assembly
procedure, on each element is defined a coefficient which is the mean
value of the 4  values of the element vertices - am I right?
My question is, suppose we have a square element with four 2x2
matrices A,B,C,D, defined on the 4 dofs (vertices of the square) like
this:

A ------- B
 |            |
 |            |
C--------D

what is the matrix coefficient defined on the element? Is it (1/4)(A+B+C+D) ?
thank you again for your time and precious work.

Marco Trevisan