Adjust to new base class interface

[[Imported from SVN: r12669]]

dune/elasticity/materials/geomexactstvenantkirchhoffmaterial.hh

@@ -67,7 +67,7 @@ public:
     }
 
     //! Evaluate the strain energy
-    ReturnType energy(const GridFunction& displace)
+    ReturnType energy(const GridFunction* displace)
     {
         ReturnType energy=0;
         const GridType& grid = this->basis_->getGridView().grid();
@@ -114,16 +114,16 @@ public:
             
         return 0.5*energy;
     }
-   
+
     //! Return the local assembler of the first derivative of the strain energy 
-    LocalLinearization& firstDerivative(const GridFunction& displace)
+    LocalLinearization& firstDerivative(GridFunction* displace)
     {
         localLinearization_->setConfiguration(displace);
         return *localLinearization_;
     }
 
     //! Return the local assembler of the second derivative of the strain energy 
-    LocalHessian& secondDerivative(const GridFunction& displace)
+    LocalHessian& secondDerivative(GridFunction* displace)
     {
         localHessian_->setConfiguration(displace);
         return *localHessian_;