Added a template meta program, that checks whether a solver is a

direct solver.
Added a method to AMG to check whether it uses a direct solver on the
coarse level.

[[Imported from SVN: r1547]]

dune/istl/paamg/amg.hh

@@ -12,6 +12,7 @@
 #include <dune/istl/solvers.hh>
 #include <dune/istl/scalarproducts.hh>
 #include <dune/istl/superlu.hh>
+#include <dune/istl/solvertype.hh>
 #include <dune/common/typetraits.hh>
 #include <dune/common/exceptions.hh>
 
@@ -204,6 +205,12 @@ namespace Dune
         matrices_->recalculateGalerkin(NegateSet<typename PI::OwnerSet>());
       }
 
+      /**
+       * @brief Check whether the coarse solver used is a direct solver.
+       * @return True if the coarse level solver is a direct solver.
+       */
+      bool usesDirectCoarseLevelSolver() const;
+
     private:
       /** @brief Multigrid cycle on a level. */
       void mgc();
@@ -653,6 +660,12 @@ namespace Dune
     }
 
 
+    template<class M, class X, class S, class PI, class A>
+    bool AMG<M,X,S,PI,A>::usesDirectCoarseLevelSolver() const
+    {
+      return IsDirectSolver< CoarseSolver>::value;
+    }
+
     template<class M, class X, class S, class PI, class A>
     void AMG<M,X,S,PI,A>::mgc(){
       if(matrix == matrices_->matrices().coarsest() && levels()==maxlevels()) {

dune/istl/pardiso.hh

@@ -4,7 +4,7 @@
 #define DUNE_PARDISO_HH
 
 #include <dune/istl/preconditioners.hh>
-
+#include <dune/istl/solvertype.hh>
 /* Change this, if your Fortran compiler does not append underscores. */
 /* e.g. the AIX compiler:  #define F77_FUNC(func) func                */
 
@@ -209,11 +209,12 @@ namespace Dune {
     int num_procs_; //!< number of processors.
   };
 
-}
-
-
-
-
+  template<class M, class X, class Y>
+  struct IsDirectSolver<SeqPardiso<M,X,Y> >
+  {
+    enum { value=true};
+  };
 
 
+} // end namespace Dune
 #endif

dune/istl/solvertype.hh

+// -*- tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+// vi: set et ts=4 sw=2 sts=2:
+#ifndef DUNE_ISTL_SOLVERTYPE_HH
+#define DUNE_ISTL_SOLVERTYPE_HH
+
+/**
+ * @file
+ * @brief Templates characterizing the type of a solver.
+ */
+namespace Dune
+{
+  template<typename Solver>
+  struct IsDirectSolver
+  {
+    enum
+    {
+      /**
+       * @brief Whether this is a direct solver.
+       *
+       * If Solver is a direct solver, this is true.
+       */
+      value =false
+    };
+  };
+} // end namespace Dune
+#endif

dune/istl/superlu.hh

@@ -26,6 +26,7 @@
 #include <dune/common/fmatrix.hh>
 #include <dune/common/fvector.hh>
 #include <dune/common/stdstreams.hh>
+#include <dune/istl/solvertype.hh>
 
 namespace Dune
 {
@@ -447,6 +448,12 @@ namespace Dune
     StatFree(&stat);
   }
   /** @} */
+
+  template<typename T, typename A, int n, int m>
+  struct IsDirectSolver<SuperLU<BCRSMatrix<FieldMatrix<T,n,m>,A> > >
+  {
+    enum { value=true};
+  };
 }
 
 #endif // HAVE_SUPERLU