Hi,

I am a bit confused with the following dxd(u) – based upon which mesh the derivative is calculated?

Tho=Th;

fespace Vh(Th,P2);

fespace Vho(Tho,P2);

Vh u;

Vho uo;

…

Tho=Th;

uo=u;

Th=movemesh (Th, …);

**dxd(u);** //first

u=u; // Is this just an interpolation?

**dxd(u);** // second

u[ ] = uo[ ]; // is this a Larangian update?

**dxd(u);** //third

Can I say the first dxd(u) is computed using the old mesh, and the second dxd(u) uses the new mesh, but the derivatives are the same? both of which are different to the third dxd(u)?

Best,

Yongxing.