[bugfix] Assemble Laplace matrix for the h1 seminorm using the correct space

Previously, the matrix was always assembled using a P1-basis, even if we used
it to measure errors of vectors pertaining to P2 or other spaces.  Nobody noticed
this, because the h1SemiNorm routine would not fail if the vector was larger
than the matrix.   Sigh...

[[Imported from SVN: r9770]]

dune/gfe/riemanniantrsolver.cc

@@ -112,11 +112,11 @@ setup(const GridType& grid,
     // //////////////////////////////////////////////////////////////////////////////////////
     //   Assemble a Laplace matrix to create a norm that's equivalent to the H1-norm
     // //////////////////////////////////////////////////////////////////////////////////////
-    typedef P1NodalBasis<typename GridType::LeafGridView,double> P1Basis;
-    P1Basis p1Basis(grid.leafGridView());
-    OperatorAssembler<P1Basis,P1Basis> operatorAssembler(p1Basis, p1Basis);
 
-    LaplaceAssembler<GridType, typename P1Basis::LocalFiniteElement, typename P1Basis::LocalFiniteElement> laplaceStiffness;
+    BasisType basis(grid.leafGridView());
+    OperatorAssembler<BasisType,BasisType> operatorAssembler(basis, basis);
+
+    LaplaceAssembler<GridType, typename BasisType::LocalFiniteElement, typename BasisType::LocalFiniteElement> laplaceStiffness;
     typedef Dune::BCRSMatrix<Dune::FieldMatrix<double,1,1> > ScalarMatrixType;
     ScalarMatrixType* A = new ScalarMatrixType;
 
@@ -151,8 +151,6 @@ setup(const GridType& grid,
     //   Create the transfer operators
     // ////////////////////////////////////
 
-    BasisType basis(grid_->leafGridView());
-
     for (size_t k=0; k<mmgStep->mgTransfer_.size(); k++)
         delete(mmgStep->mgTransfer_[k]);