[ff3d-users] Newbie question

[Luigi Bardelli]

Hi all!
   I have just started using ff3d and I have a really newbie question:
if I write:

vector n=(10,10,10);
vector a=(0,0,0);
vector b=(300,300,300);
mesh MESH = structured(n,a,b);
scene SCENE = pov("empty.pov"); // empty.pov is empty...
                                // is scene needed?
solve(V) in MESH
{
  pde(V)
    dx(dx(V))+dy(dy(V))+dz(dz(V))=0;

  V=V1 on MESH zmax;
  V=V2 on MESH zmin;
}

I get the following:
Parsing the file ..........    done
Treating data
Building Mesh ... done
PDEOperatorSumExpression.cpp:56: Not implemented

And then aborts... If I use  dx(V)+dy(V)+dz(V)=0; it works.

I'm sure I'm missing something... can you help?
Thank you
    Luigi

(Running on Linux 2.6 with the today CVS)