model determins whether advection or diffusion is enabled.

dune/fem-dg/test/advdiff/Makefile.am

@@ -22,9 +22,6 @@ GRIDDIM  = 2
 DIMRANGE = 1
 FLUX = 1    # LLF 1, HLL 2
 
-ADVECTION=0
-DIFFUSION=1
-
 #USE_OMP=-fopenmp
 
 # INFO SPACE OPERATOR:
@@ -40,7 +37,6 @@ check_PROGRAMS = advdiff advdiffonep advdiff12 # quasiadvdiff quasiadvdiff12 pla
 
 AM_CPPFLAGS = $(USE_OMP) -I../../problems/advdiff  $(ALL_PKG_CPPFLAGS) -DGRIDDIM=$(GRIDDIM) \
 							-D$(GRIDTYPE) $(DUNEMPICPPFLAGS) \
-              -DADVECTION=$(ADVECTION)  -DDIFFUSION=$(DIFFUSION) \
 							-DDIMRANGE=$(DIMRANGE) -DFLUX=$(FLUX) -DPRIMALDG -DUSE_ASSERT_THROW
 AM_LDFLAGS = $(ALL_PKG_LDFLAGS) $(LAPACK_LDFLAGS) $(USE_OMP)
 

dune/fem-dg/test/advdiff/models.hh

@@ -88,6 +88,10 @@ template <class GridPartType,class ProblemImp>
 class HeatEqnModel : public DefaultModel < HeatEqnModelTraits< GridPartType > >
 {
 public:
+  // for heat equations advection is disabled 
+  static const bool hasAdvection = false ;
+  static const bool hasDiffusion = true  ;
+
   typedef ProblemImp ProblemType ;
 
   static const int ConstantVelocity = ProblemType :: ConstantVelocity;

dune/fem-dg/test/advdiff/problemcreator.hh

@@ -25,7 +25,7 @@ struct ProblemGenerator
                       Dune::Fem::FunctionSpace< double, double, GridType::dimension,
                       DIMRANGE>,
                       false > ProblemType;
-  //typedef HeatProblemType ProblemType;
+  // define problem type here if interface should be avoided
 
   template< class GridPart >
   struct Traits
@@ -33,6 +33,7 @@ struct ProblemGenerator
     typedef ProblemType  InitialDataType;
     typedef HeatEqnModel< GridPart, InitialDataType > ModelType;
     typedef LLFFlux< ModelType > FluxType;
+
     //typedef UpwindFlux< ModelType > FluxType;
     // choice of diffusion flux (see diffusionflux.hh for methods)
      static const Dune :: DGDiffusionFluxIdentifier PrimalDiffusionFluxId 

dune/fem-dg/test/advdiff/steppertraits.hh

@@ -63,27 +63,43 @@ private:
   typedef Dune :: DGDiffusionOperator< ModelType, FluxType,
                                        DiffusionFluxId, polynomialOrder >      DgDiffusionType;
 
+
+  // default is that both are enabled 
+  template < bool advection, bool diffusion >
+  struct OperatorChooser
+  {
+    typedef DgType          FullOperatorType;
+    typedef DgDiffusionType ImplicitOperatorType;
+    typedef DgAdvectionType ExplicitOperatorType;
+  };
+
+  // advection operator only, i.e. linear advection equation
+  template < bool advection >
+  struct OperatorChooser< advection, false >
+  {
+    typedef DgAdvectionType  FullOperatorType;
+    typedef FullOperatorType ImplicitOperatorType;
+    typedef FullOperatorType ExplicitOperatorType;
+  };
+
+  // diffusion operator only, i.e. for the heat equation 
+  template < bool diffusion >
+  struct OperatorChooser< false, diffusion >
+  {
+    typedef DgDiffusionType  FullOperatorType;
+    typedef FullOperatorType ImplicitOperatorType;
+    typedef FullOperatorType ExplicitOperatorType;
+  };
 public:
 
+  static const bool advection = ModelType :: hasAdvection ;
+  static const bool diffusion = ModelType :: hasDiffusion ;
 
-#if ADVECTION && DIFFUSION
-#warning "Using Advection-Diffusion Operator"
-  typedef DgType          FullOperatorType;
-  typedef DgDiffusionType ImplicitOperatorType;
-  typedef DgAdvectionType ExplicitOperatorType;
-#elif ADVECTION 
-#warning "Using Advection Operator"
-  typedef DgAdvectionType  FullOperatorType;
-  typedef FullOperatorType ImplicitOperatorType;
-  typedef FullOperatorType ExplicitOperatorType;
-#elif DIFFUSION 
-#warning "Using Diffusion Operator"
-  typedef DgDiffusionType  FullOperatorType;
-  typedef FullOperatorType ImplicitOperatorType;
-  typedef FullOperatorType ExplicitOperatorType;
-#else 
-#error "Either ADVECTION or DIFFUSSION has to be set" 
-#endif
+  typedef OperatorChooser< advection, diffusion > OperatorChooserType ;
+
+  typedef typename OperatorChooserType :: FullOperatorType      FullOperatorType;
+  typedef typename OperatorChooserType :: ImplicitOperatorType  ImplicitOperatorType;
+  typedef typename OperatorChooserType :: ExplicitOperatorType  ExplicitOperatorType;
 
   // The discrete function for the unknown solution is defined in the DgOperator
   typedef typename DgType :: DestinationType                         DiscreteFunctionType;