As one further step towards making LocalInterpolationRules
more like (local) functions, introduce a new method 'bind'
accepting a local finite element and a set of (local)
coefficients.  This method replaces the constructor
taking the same arguments. Instead, the local function object
now has to be default constructed.  This is just an
intermediate step, however.

Instead of hard-coding LocalGeodesicFEFunction.

MixedGFEAssembler is not part of an inheritance hierarchy.

It doesn't look like this code ever worked.

There is a generic mechanism for surface loads in form of the
NeumannEnergy class (to be replaced soon(TM) by something
even more generic).  This is what should be used, instead
of ad hoc implementations such as the one in SimoFoxEnergy.

Because it is an energy, not a local stiffness.

It was non-virtual by oversight.

Rather than a LocalFiniteElement.  This makes LocalGeodesicFEFunction
more like a dune-functions-style local function, which I think
it should be.

Rather than a LocalFiniteElement.  This makes LocalGeodesicFEFunction
more like a dune-functions-style local function, which I think
it should be.

I don't think it is worth keeping it, even if it may be
a bit faster than the general code.

The class LocalGfeTestFunctionBasis was removed in a recent commit,
and I forgot to remove a friend declaration for it.

This patch contains only whitespace changes.

Previously, some code was in Dune::GFE, some was in Dune::,
and a lot of it was in the global namespace.

I wrote them years ago mainly because I thought they should exist.
But they were never actually used them for anything, and I don't
really know were they could be used either.  Supposedly they
could be useful for implementing problems without a minimization
formulation, but that's not currently planned, and I don't know
what the precise requirements would be, either.

Since the code is short and almost trivial, and easily resurrected,
this commit removes the two files.  For newcomers this will mean
two less files to wonder about.

It is default-implemented in LocalDensity itself, and therefore
density implementations don't have to implement it themselves
unless they need to do something nonstandard.

Rather than just on the type for points in the domain.
The point type is not enough: For example, if the density involves
a coefficient function given as a GridView function, then the
density has to be able to bind the local coefficient function
to the correct element, for which it has to know the element type.

Integration domains can be elements (i.e., Codim<0>::Entity)
or Intersections.

The actual bind method will follow in a separate commit.

I suspect that calling the density through LocalDensity::operator()
doesn't work yet, because the GFE function derivatives are not
transformed correctly from the reference to the grid element.
Therefore that new method still aborts with a deliberate error
message, until I have the time to check.

This allows to fix the incorrect coordinate type that was expected
for evaluating the density.

Currently, densities only get the type used for coordinates
of the integration domain.  However, this is not enough:
The complete domain must be known, and this domain can be either
a grid element or a grid intersection.

As a first small step, this patch introduces ElementOrIntersection
as a template parameter of the CosseratShellDensity class.

This is one step towards turning SurfaceCosseratEnergy into a
generic SurfaceIntegralEnergy class.

They are unused -- all code uses the space-dependent parameters.

For my current clang 19.1.5 they are an error.

This can be used in makeComposedGridFunction to turn quaternion-valued
functions to matrix-type ones, and vice versa.

Previously, the writer requested an FE basis to represent the director
vectors.  With the help of ComposedGridViewFunction this patch allows
to avoid this extra basis, which makes for a much nicer interface
for CosseratVTKWriter.

The NonplanarCosseratShellEnergy class contains a reimplementation of
the energy density of CosseratShellDensity.  The code is much easier
to understand and maintain if the density implementation of
CosseratShellDensity is used instead.