From: bangerth <bangerth@0785d39b-7218-0410-832d-ea1e28bc413d>
Date: Sat, 18 Dec 2010 05:00:38 +0000 (+0000)
Subject: Also introduce MGDoFAccessor<0,1,spacedim>.
X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a496c94679fc74b5f7d7c8ae443b8b55e40cffa2;p=dealii-svn.git

Also introduce MGDoFAccessor<0,1,spacedim>.

git-svn-id: https://svn.dealii.org/trunk@23000 0785d39b-7218-0410-832d-ea1e28bc413d
---

diff --git a/deal.II/include/deal.II/dofs/dof_accessor.h b/deal.II/include/deal.II/dofs/dof_accessor.h
index b74f47048e..d33b447bac 100644
--- a/deal.II/include/deal.II/dofs/dof_accessor.h
+++ b/deal.II/include/deal.II/dofs/dof_accessor.h
@@ -859,7 +859,7 @@ class DoFAccessor<0,DH<1,spacedim> > : public TriaAccessor<0,1,spacedim>
 				      * do anything useful here and so
 				      * may not actually be called.
 				      */
-    DoFAccessor (const Triangulation<1,spacedim> * =  0,
+    DoFAccessor (const Triangulation<1,spacedim> *,
 		 const int = 0,
 		 const int = 0,
 		 const DH<1,spacedim> * = 0);
diff --git a/deal.II/include/deal.II/multigrid/mg_dof_accessor.h b/deal.II/include/deal.II/multigrid/mg_dof_accessor.h
index 42a14d8942..438add06a8 100644
--- a/deal.II/include/deal.II/multigrid/mg_dof_accessor.h
+++ b/deal.II/include/deal.II/multigrid/mg_dof_accessor.h
@@ -338,6 +338,14 @@ class MGDoFAccessor : public internal::MGDoFAccessor::Inheritance<structdim,dim,
 				      * @}
 				      */
 
+				     /**
+				      * Return a handle on the
+				      * DoFHandler object which we
+				      * are using.
+				      */
+    const MGDoFHandler<dim,spacedim> &
+    get_mg_dof_handler () const;
+
 				     /**
 				      * Return an iterator pointing to
 				      * the the parent.
@@ -413,6 +421,161 @@ class MGDoFAccessor : public internal::MGDoFAccessor::Inheritance<structdim,dim,
 };
 
 
+
+/**
+ * Specialization of the general MGDoFAccessor class template for the
+ * case of zero-dimensional objects (a vertex) that are the face of a
+ * one-dimensional cell in spacedim space dimensions. Since vertices
+ * function differently than general faces, this class does a few
+ * things differently than the general template, but the interface
+ * should look the same.
+ *
+ * @author Wolfgang Bangerth, 2010
+ */
+template <int spacedim>
+class MGDoFAccessor<0,1,spacedim> : public internal::MGDoFAccessor::Inheritance<0,1,spacedim>::BaseClass
+{
+  public:
+				     /**
+				      * Declare a typedef to the base
+				      * class to make accessing some
+				      * of the exception classes
+				      * simpler.
+				      */
+    typedef
+    typename internal::MGDoFAccessor::Inheritance<0,1,spacedim>::BaseClass
+    BaseClass;
+
+				     /**
+				      * A typedef necessary for the
+				      * iterator classes.
+				      */
+    typedef MGDoFHandler<1,spacedim> AccessorData;
+
+				     /**
+				      * The dof handler type used by
+				      * this accessor.
+				      */
+    typedef MGDoFHandler<1, spacedim> Container;
+
+				     /**
+				      * @name Constructors
+				      */
+				     /**
+				      * @{
+				      */
+
+				     /**
+				      * Default constructor. Provides
+				      * an accessor that can't be
+				      * used.
+				      */
+    MGDoFAccessor ();
+
+				     /**
+				      * Constructor to be used if the
+				      * object here refers to a vertex
+				      * of a one-dimensional
+				      * triangulation, i.e. a face of
+				      * the triangulation.
+				      *
+				      * Since there is no mapping from
+				      * vertices to cells, an accessor
+				      * object for a point has no way
+				      * to figure out whether it is at
+				      * the boundary of the domain or
+				      * not. Consequently, the second
+				      * argument must be passed by the
+				      * object that generates this
+				      * accessor -- e.g. a 1d cell
+				      * that can figure out whether
+				      * its left or right vertex are
+				      * at the boundary.
+				      *
+				      * The third argument is the
+				      * global index of the vertex we
+				      * point to.
+				      *
+				      * The fourth argument is a
+				      * pointer to the MGDoFHandler
+				      * object.
+				      *
+				      * This iterator can only be
+				      * called for one-dimensional
+				      * triangulations.
+				      */
+    MGDoFAccessor (const Triangulation<1,spacedim> * tria,
+		   const typename TriaAccessor<0,1,spacedim>::VertexKind vertex_kind,
+		   const unsigned int    vertex_index,
+		   const MGDoFHandler<1,spacedim> * dof_handler);
+
+				     /**
+				      * Constructor. This constructor
+				      * exists in order to maintain
+				      * interface compatibility with
+				      * the other accessor
+				      * classes. However, it doesn't
+				      * do anything useful here and so
+				      * may not actually be called.
+				      */
+    MGDoFAccessor (const Triangulation<1,spacedim> * =  0,
+		   const int = 0,
+		   const int = 0,
+		   const MGDoFHandler<1,spacedim> * = 0);
+
+				     /**
+				      * Conversion constructor. This
+				      * constructor exists to make certain
+				      * constructs simpler to write in
+				      * dimension independent code. For
+				      * example, it allows assigning a face
+				      * iterator to a line iterator, an
+				      * operation that is useful in 2d but
+				      * doesn't make any sense in 3d. The
+				      * constructor here exists for the
+				      * purpose of making the code conform to
+				      * C++ but it will unconditionally abort;
+				      * in other words, assigning a face
+				      * iterator to a line iterator is better
+				      * put into an if-statement that checks
+				      * that the dimension is two, and assign
+				      * to a quad iterator in 3d (an operator
+				      * that, without this constructor would
+				      * be illegal if we happen to compile for
+				      * 2d).
+				      */
+    template <int structdim2, int dim2, int spacedim2>
+    MGDoFAccessor (const InvalidAccessor<structdim2,dim2,spacedim2> &);
+
+				     /**
+				      * Another conversion operator
+				      * between objects that don't
+				      * make sense, just like the
+				      * previous one.
+				      */
+    template <int structdim2, int dim2, int spacedim2>
+    MGDoFAccessor (const MGDoFAccessor<structdim2, dim2, spacedim2> &);
+
+
+				     /**
+				      * Another conversion operator
+				      * between objects that don't
+				      * make sense, just like the
+				      * previous one.
+				      */
+    template <int dim2, int spacedim2>
+    MGDoFAccessor (const MGDoFCellAccessor<dim2, spacedim2> &);
+
+  protected:
+				     /**
+				      * Store the address of the @p MGDoFHandler object
+				      * to be accessed.
+				      */
+    MGDoFHandler<1,spacedim> *mg_dof_handler;
+};
+
+
+
 /* -------------------------------------------------------------------------- */
 
 
diff --git a/deal.II/include/deal.II/multigrid/mg_dof_iterator_selector.h b/deal.II/include/deal.II/multigrid/mg_dof_iterator_selector.h
index bcbdc8fbfc..716a864cbb 100644
--- a/deal.II/include/deal.II/multigrid/mg_dof_iterator_selector.h
+++ b/deal.II/include/deal.II/multigrid/mg_dof_iterator_selector.h
@@ -45,8 +45,8 @@ namespace internal
     {
       public:
 	typedef dealii::MGDoFCellAccessor<1,spacedim> CellAccessor;
-	typedef InvalidAccessor<0,1,spacedim> FaceAccessor;
-	
+	typedef dealii::MGDoFAccessor<0,1,spacedim> FaceAccessor;
+
 	typedef TriaRawIterator   <CellAccessor> raw_line_iterator;
         typedef TriaIterator      <CellAccessor> line_iterator;
         typedef TriaActiveIterator<CellAccessor> active_line_iterator;
@@ -80,11 +80,11 @@ namespace internal
       public:
 	typedef dealii::MGDoFCellAccessor<2,spacedim> CellAccessor;
 	typedef dealii::MGDoFAccessor<1,2,spacedim> FaceAccessor;
-	
+
         typedef TriaRawIterator   <FaceAccessor> raw_line_iterator;
         typedef TriaIterator      <FaceAccessor> line_iterator;
         typedef TriaActiveIterator<FaceAccessor> active_line_iterator;
-    
+
         typedef TriaRawIterator   <CellAccessor> raw_quad_iterator;
         typedef TriaIterator      <CellAccessor> quad_iterator;
         typedef TriaActiveIterator<CellAccessor> active_quad_iterator;
@@ -99,7 +99,7 @@ namespace internal
 
         typedef raw_line_iterator    raw_face_iterator;
         typedef line_iterator        face_iterator;
-        typedef active_line_iterator active_face_iterator;    
+        typedef active_line_iterator active_face_iterator;
     };
 
 
@@ -133,7 +133,7 @@ namespace internal
 
         typedef raw_quad_iterator    raw_face_iterator;
         typedef quad_iterator        face_iterator;
-        typedef active_quad_iterator active_face_iterator;    
+        typedef active_quad_iterator active_face_iterator;
     };
   }
 }
diff --git a/deal.II/source/multigrid/mg_dof_accessor.cc b/deal.II/source/multigrid/mg_dof_accessor.cc
index b5efa2acfc..61007de2d5 100644
--- a/deal.II/source/multigrid/mg_dof_accessor.cc
+++ b/deal.II/source/multigrid/mg_dof_accessor.cc
@@ -65,6 +65,15 @@ MGDoFAccessor<structdim, dim, spacedim>::set_mg_dof_handler (MGDoFHandler<dim,sp
 
 
 
+template <int structdim, int dim, int spacedim>
+const MGDoFHandler<dim,spacedim> &
+MGDoFAccessor<structdim, dim, spacedim>::get_mg_dof_handler () const
+{
+  return *mg_dof_handler;
+}
+
+
+
 template <int structdim,int dim, int spacedim>
 unsigned int
 MGDoFAccessor<structdim, dim, spacedim>::mg_vertex_dof_index (const int level,
@@ -454,9 +463,78 @@ get_mg_dof_values (const int level,
 
 
 
+/*------------------------- Functions: MGDoFAccessor<0,1,spacedim> -----------------------*/
+
+template <int spacedim>
+inline
+MGDoFAccessor<0,1,spacedim>::MGDoFAccessor ()
+		:
+		BaseClass ()
+{
+  Assert (false, typename BaseClass::ExcInvalidObject());
+}
+
+
+
+template <int spacedim>
+inline
+MGDoFAccessor<0,1,spacedim>::
+MGDoFAccessor (const Triangulation<1,spacedim> *tria,
+	       const typename TriaAccessor<0,1,spacedim>::VertexKind vertex_kind,
+	       const unsigned int    vertex_index,
+	       const MGDoFHandler<1,spacedim> * dof_handler)
+		:
+		BaseClass (tria,
+			   vertex_kind,
+			   vertex_index),
+                mg_dof_handler(const_cast<MGDoFHandler<1,spacedim>*>(dof_handler))
+{}
+
+
+
+template <int spacedim>
+inline
+MGDoFAccessor<0,1,spacedim>::
+MGDoFAccessor (const Triangulation<1,spacedim> *,
+	       const int                 ,
+	       const int                 ,
+	       const MGDoFHandler<1,spacedim>     *)
+		:
+                mg_dof_handler(0)
+{
+  Assert (false,
+	  ExcMessage ("This constructor can not be called for face iterators in 1d."));
+}
+
+
+
+template <int spacedim>
+template <int structdim2, int dim2, int spacedim2>
+MGDoFAccessor<0,1,spacedim>::MGDoFAccessor (const InvalidAccessor<structdim2,dim2,spacedim2> &)
+{
+  Assert (false, typename BaseClass::ExcInvalidObject());
+}
 
 
 
+template <int spacedim>
+template <int structdim2, int dim2, int spacedim2>
+inline
+MGDoFAccessor<0,1,spacedim>::MGDoFAccessor (const MGDoFAccessor<structdim2, dim2, spacedim2> &)
+{
+  Assert (false, typename BaseClass::ExcInvalidObject());
+}
+
+
+
+template <int spacedim>
+template <int dim2, int spacedim2>
+inline
+MGDoFAccessor<0,1,spacedim>::MGDoFAccessor (const MGDoFCellAccessor<dim2, spacedim2> &)
+{
+  Assert (false, typename BaseClass::ExcInvalidObject());
+}
+
 
 
 /*------------------------- Functions: MGDoFCellAccessor -----------------------*/
@@ -538,25 +616,65 @@ MGDoFCellAccessor<dim, spacedim>::parent () const
 }
 
 
+namespace internal
+{
+  namespace MGDoFCellAccessor
+  {
+    template <int spacedim>
+    inline
+    typename internal::MGDoFHandler::Iterators<1,spacedim>::face_iterator
+    get_face (const dealii::MGDoFCellAccessor<1,spacedim> &cell,
+	      const unsigned int i,
+	      const internal::int2type<1>)
+    {
+      dealii::MGDoFAccessor<0,1,spacedim>
+	a (&cell.get_triangulation(),
+      	   ((i == 0) && cell.at_boundary(0)
+      	    ?
+      	    dealii::TriaAccessor<0, 1, spacedim>::left_vertex
+      	    :
+      	    ((i == 1) && cell.at_boundary(1)
+      	     ?
+      	     dealii::TriaAccessor<0, 1, spacedim>::right_vertex
+      	     :
+      	     dealii::TriaAccessor<0, 1, spacedim>::interior_vertex)),
+      	   cell.vertex_index(i),
+	   &cell.get_mg_dof_handler());
+      return typename internal::MGDoFHandler::Iterators<1,spacedim>::face_iterator(a);
+    }
+
+
+    template <int spacedim>
+    inline
+    typename internal::MGDoFHandler::Iterators<2,spacedim>::face_iterator
+    get_face (const dealii::MGDoFCellAccessor<2,spacedim> &cell,
+	      const unsigned int i,
+	      const internal::int2type<2>)
+    {
+      return cell.line(i);
+    }
+
+
+    template <int spacedim>
+    inline
+    typename internal::MGDoFHandler::Iterators<3,spacedim>::face_iterator
+    get_face (const dealii::MGDoFCellAccessor<3,spacedim> &cell,
+	      const unsigned int i,
+	      const internal::int2type<3>)
+    {
+      return cell.quad(i);
+    }
+  }
+}
+
+
 template <int dim, int spacedim>
 typename internal::MGDoFHandler::Iterators<dim,spacedim>::face_iterator
 MGDoFCellAccessor<dim,spacedim>::face (const unsigned int i) const
 {
-  switch (dim)
-    {
-      case 1:
-	    Assert (false, ExcImpossibleInDim(1));
-	    return
-	      typename internal::MGDoFHandler::Iterators<dim,spacedim>::face_iterator();
-      case 2:
-	    return this->line(i);
-      case 3:
-	    return this->quad(i);
-      default:
-	    Assert (false, ExcNotImplemented());
-	    return
-	      typename internal::MGDoFHandler::Iterators<dim,spacedim>::face_iterator();
-    }
+  Assert (i<GeometryInfo<dim>::faces_per_cell, ExcIndexRange (i, 0, GeometryInfo<dim>::faces_per_cell));
+
+  return internal::MGDoFCellAccessor::get_face (*this, i, internal::int2type<dim>());
 }
 
 
diff --git a/deal.II/source/multigrid/mg_dof_accessor.inst.in b/deal.II/source/multigrid/mg_dof_accessor.inst.in
index 4888f59abb..4fdcec74de 100644
--- a/deal.II/source/multigrid/mg_dof_accessor.inst.in
+++ b/deal.II/source/multigrid/mg_dof_accessor.inst.in
@@ -82,6 +82,9 @@ for (deal_II_dimension : DIMENSIONS)
 
 
 #if deal_II_dimension == 1
+  template class MGDoFAccessor<0, 1, 1>;
+  template class MGDoFAccessor<0, 1, 2>;
+
   template class MGDoFAccessor<1, 1, 1>;
   template class MGDoFAccessor<1, 1, 2>;