[dune-pdelab] dim < dimWorld ?

[Christian Engwer]

Hi Bernd,

> One could fix this by declaring gradphi as a dimWorld-vector, but I
> don't think that this is what we want to do. We want to solve an
> equation like
> div_s D_s grad_s u_s = q_s
> where all _s are surface quantities. The vectors and tensors have a
> dimWorld coordinate representation, but I think that one would want
> to use the dim representations.

on the contrary, if you look into the sfem stuff, you consider a
problem in dimW, but assemble on the surface.

> So either jacobianInverseTransposed should map to a dim-coordinate
> vector, or one should have a method for projecting
> dimWorld-representations to dim-representations. What do you think?

you are mapping to global coordinates and these are dimW, so the
jacobian has to map to dimW aswell.

I agree that some (or most) operators will not work for surface
problems, but the necessary changes are simply to use the appropriate
vector sizes.

Christian